Weather456's Tropical Weather Blog

Tuesday 19th September Tropical and Subtropical Weather

By: Weather456, 12:22 PM GMT on September 19, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Western Periphery………..
Tuesday, September 19, 2006
11:00 UTC
07:29:38 AM AST


A frontal boundary that was once stationary, now consist of a warm front draped across the Southern Canada from 51N/82W to 45N/55W, and cold front that extends from 45N/55W to near Gordon, and curves northward to a gale low near 55N/25W. A stream of moisture is seen all along the two fronts from SE Canada to the Atlantic Ocean.

A well define frontal trough extends from Canada at 50N/78W across the entire United States sub-continent, to the Gulf of Mexico near the Texas/Mexican Border. Numerous scattered strong T-Storms accompanied by a possibilities of severe weather, accompanied the front and will spread into the Eastern Part of Canada and the United States. A surface trough is located along the trough between south of New Orleans, Louisiana and off the coast of Brownsville, Texas. A cut off low (surface) might form along the trough, in this area, so its an area of interest for me, just to see what will happen.

Just behind the trough is an upper air low, spining over Lake Superior, accompanied by cold polar air, reducing temperatures across the Northern Mid-West of the USA to near or below freezing in some spots (See figure 1).

An upper level ridge, centred on a closed high in the Central Gulf of Mexico at 25N/91W, is giving way to the frontal trough.

The interaction with the southern edge of the ridge and the upper air high is helping to enhance widespread strong T-Storms, across Mexico, the Bay of Campeche, Mexican Yucatan Peninsula, Belize, Guatemala, San Salvador, Honduras and Nicaragua. These areas should expect locally heavy rainfall of up to 4inches.

A very broad mid-upper level trough, extends across the Western Atlantic, from Bermuda to Florida and the Bahamas, is helping to generate some showers over the Florida Peninsula, Bermuda and the Bahamas. A mid-upper level low (95L) is located along the trough near 36N/70W. I no longer expect much of this, since it will be absorbed soon by a more intense trough its west.

A weak surface high (1018mbar) is centred near 25N/65W, between Puerto Rico and Bermuda.

Scattered showers are seen along the ITCZ spreading into Costa Rico, Panama, Northern Colombia and Venezuela. Some of the moisture surge is spreading north of the ITCZ into the Caribbean Sea and across some of the Islands.

A 250hpa, continues to sit over the Leeward Islands, and the dry sinking air should be coming to an end as surges from tropical waves, and the ITCZ start progressing west.


Figure 1: Temperatures Recorded at 5:36AST at cities located across North Dakota.

Weather456

Atlantic Ocean: 95L, Remnants of Lane, Helene, Gordon and an African Wave

By: Weather456, 12:21 PM GMT on September 18, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Western Periphery………..
18/09/06
08:06:19 AM AST


A cold front now extends from a developing low pressure system near 49N/90W, over the Great Lakes region to the Atlantic Ocean near 51N/52W. The front is accompanied by moderate-strong showers spreading across Southern Canada from Ontario to Newfoundland, the Great Lake States, and parts of the NE USA. Locally heavy rains with a chance of a thunderstorms or two are expected over the area.

A cold front extends from the same low pressure system near 49N/90W across much of Continental USA to the Texas/Mexican border where a 1008mbar low (the remnants of Lane) is located. As with yesterday, the frontal trough will be accompanied by severe weather (heavy rains, gusty winds, tornadoes and T-Storms), notable over southern Texas and northern Mexico, where the remnants of Lane is helping to produce heavy T-Showers with rainfall accumulations of 2-5inches in the past 24hrs.
If the low, along the front is able to enter the Gulf of Mexico intact, then there are some chances of tropical development, if conditions allow.

An upper level trough, accompanied by a waning front now extends from 30N/72W to 45N/68W, with a mid-upper level low (95L) along its axis near 35N. This low was once a true TUTT, but the circulation made it to the mid-layers. The system remains frontal, meaning its non tropical, but could become subtropical soon, then tropical later. Quicksat pass, buoys, visible imagery and 850mbar streamline winds, revealed a closed circulation with winds of 20-25knots. The same buoy measured a pressure of 1004mbars, so the lowest measured pressure stands at that. The low has limited convection due to hostile upper air winds and cool SSTs.

An upper level ridge that extends from the Texas/Mexican coastal border, across the Gulf of Mexico, north into the heart of the USA, is giving way to the frontal trough to its west and will move further to the east and south as the trough comes down. The ridge is also helping to create warm air temperatures across much the South-East USA and the North-East USA.

A surface trough extends from 30N/65W to the NW Caribbean Sea will produce scattered isolated T-Showers across Bermuda, the Central Bahamas, Cuba, Jamaica, the Caymans Islands and the Yucatan Peninsula, including Belize.

A tropical wave has moved inland over Central America.

Strong Showers and T-Storms will spread across Panama and Costa Rico in association with the ITCZ, expect locally heavy rain accumulation of up to 5inches (7inches in higher elevations).

Much of the Eastern and Central Caribbean Sea, remains cloud-free, and limited in convective activity due to dry, sinking, stable air, being channeled in by a mid-level high north of the Leeward Islands.

Weather456

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Eastern Periphery………..
18/09/06
04:30:15 PM AST


As of 5PM AST, Major Hurricane Helene was located near 23.9N/51.1W, movong to the WNW near 9mph. Helene is packing winds of 115mph and has a MCP of 960mbars. (Details Later)

As of 5PM AST, Hurricane Gordon was located near 37.8N/44.8W, moving to the ENE at 21mph. Gordon is packing winds of 90mph with a MCP of 977mbars.

The only tropical wave to speak about this afternoon is along 29W, void of all convection due to a dry environment created by a nearby TUTT.

Numerous scattered showers are seen along the ITCZ between 25W and the African Mainland, south of 15N. These showers maybe associated with a tropical wave accompanied by a broad area of low pressure based on 850mb streamline winds and visible imagery.

An upper level trough extends from Morocco to 15N/31W, with a TUTT spinning nearly stationary near 19N/31W. Showers and T-Storms are streaming into the Madeira Islands and Morocco from the Atlantic Ocean thanks to the trough.

The upper air trough sits between two upper air highs centred near 15N/43W and the other along the African Coast near 19N/18W.

Surface ridging centred on closed 850hpa high dominates most of the Eastern Atlantic, east of Helene's longitude.

A cold front extends from 42N/20W, towards Ireland, then recurved north-westward to a 990mbar gale low near 55N/11W. The gale is along a surface trough that extends to meet another 990mbar low near 60N/15W. The two lows are forecast to merge into one low pressure system, brining gusty T-Showers with high seas to Ireland and the UK, spreading into Norway, later in the week.

Another gale storm, located near 45W/50N, just south of Greenland. Mostly breezy weather with high choppy seas will be experience on the southern facing coastline of Greenland.

Weather456

Today's Discussion

By: Weather456, 2:32 PM GMT on September 17, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Western Periphery………..
17/09/06
08:59:40 AM AST


A stationary front continues to be draped across Southern Canada from 95W, to the North Atlantic Ocean near 60W. Isolated T-Showers are scattered along the front, notable very intense over Wisconsin and Lake Superior (U.S.A and Canadian Peripheries).

A cold front extends from New Brunswick, Canada to near 50N/35W. Numerous isolated T-Showers are seen along the front.

A frontal trough (a frontal system in association with a trough) extends from Arizona, across New Mexico, over the Texas Panhandle, north across much of the Central United States, coming to an end near 46N/95W. Numerous widespread severe T-showers extends from Texas (which is also associated with moisture from Lane, See Below) to Michigan.

The upper level trough that extended across the Eastern United States, as retreat more to the NE, and now extends from south of Nova Scotia, to 30N/78W. Along the trough is a TUTT located off the Atlantic Coast of New Jersey. The low is generating some moisture that will spread into the states of New York, Connecticut and Rode Island.

The remainder of the trough remains extremely dry due to dry sinking air that came down behind the trough and an area of high pressure centered over West Virgina. Mainly clear skies and near average temperatures will be expected from Northern Florida, all the way to Pennsylvania.

Ahead of the trough is a dying frontal boundary. There are two lows located along the system. One near 36N/70W, and the other (mainly extra topical) near 41N/60W. Widespread T-Showers, will spread across the Bahamas and Bermuda, in association with the old frontal system.

A broad upper air ridge/high is extending from Central Mexico, all the way north into the heart of continental United States. One western edge of the high, the remnants of Hurricane Lane, will interact with the first frontal system discussed above, to produce life threating rains of up to 50mm in 3hrs, across Texas and New Mexico. Please refer the local NWS, on issues of flood watches and warnings.

Most of the Gulf of Mexico remains tranquil and cloud-free due to dry sinking air moving down from the United Sates.

A tropical wave along 82W is interacting with the eastern edge of the upper level high to produce widespread T-showers across much of the NW Caribbean Sea from the Yucatan Peninsula to Jamaica, south to Honduras. The southern edge of the wave axis is along the ITCZ, helping to generate numerous widespread Showers along the remainder Central America and Colombia.
Rainfall totals along Central America and the NW Caribbean Sea, including Southern Florida and the Bahamas will be around 20-40mm in 3hrs.

On the flip side, cloud-free skies dominate most of the Eastern Caribbean Sea, east of 70W, due to large amounts of dry Saharan dust being channeled into the area by an upper air high to the north of Puerto Rico. Though an isolated stray shower or two could be expected over some areas.

Weather456

Could Tropical Or Subtropical Storm Isaac have Formed Today?

By: Weather456, 12:49 AM GMT on September 17, 2006

As part of one my daily discussion, I identified a low pressure system near 39N/66W, this morning:

Ahead of the trough is a frontal boundary, extending from the Florida Keys and Northern Bahamas to near 40N/65W. Numerous showers and T-Storms are all along front spreading into the Northern Bahaman Islands, Southern Florida Peninsula, Florida Keys and the Western End of Cuba. There are three features along the front:

(A) A 1010mbar low along the frontal boundary off the East Coast of The United States, is located near 34N/74W. Quiksat pass revealed a well-defined closed circulation with winds of 20-25knots and a couple of buoys located near the low reported 20knot sustain winds. The low is almost void of all convection due to the immense sinking dry air behind the frontal boundary, and wind shear is very hostile, of about 40+ knots.

(B) A 1008mbar low is located near 39N/66W, will most likely become extra topical soon. Quiksat pass, visible imagery and 850mbar streamline winds revealed a well-define closed circulation with winds of 35-40knots, mostly in the NW quadrant. 500mbar winds revealed a weak circulation in the mid-layers, but 850mbar (surface) winds revealed a stronger circulation at lower levels.


(C) A surface trough that was in the upper layers is accompanied by moderate to strong T-Storms, extending from 25N/75W to 31N/67.5W. Showers activity from the trough is spreading into the Central Bahaman Islands and more rain will be expected as the front begins to moves in.


Given the information, it does appear that this might have been a tropical or subtropical storm, but further investigation revealed it may have been an extra topical cyclone.

The low was frontal, and tropical systems are not. The low comprised of northward moving warm air overriding colder air to the north (warm front), and colder air digging under warmer air to the south (cold front). (See Image Below)

Sometimes extra topical systems can transition into something tropical or subtropical, under the right conditions.


Figure One: Extratropical Storms, are comprise of a northward moving warm front (warm air riding over colder air) and an eastward or southeastward moving cold front (cold air digging under warmer air). Tropical Systems are non-frontal (comprises of warm air rising leading to convective activity), therefore, it can be concluded that the system today was mainly a mid-latitude cyclone.


Figure Two: Visible Image of the low pressure system.

Western Atlantic Disucussion and Gordon and Helene

By: Weather456, 9:15 PM GMT on September 14, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Western Periphery………..
09/14/06
04:59:55 PM AST


A cold front, accompanied by moderate to strong convection extends from Western Greenland across the Labrador Sea, into Ontario near Great Lakes area.

An upper level trough extends from the Hudson Bay into the heart of Ontario is accompanied by intense shower and T-Storms activity. Locally heavy rain accumulations are expected over the area.

Surface ridging dominates most of South Eastern Canada and the North-East United States.

What's left of Florence has become a powerful gale/extra topical storm, moving away from the Newfoundland Atlantic Coast. The weather in the area should be improving tonight. The gale is packing winds of 50+ knots and has a MCP of 974mbars.

An upper level trough extends from the Great Lakes Area to the southernmost Gulf Coast States. Most of the showers and T-Storms activity is ahead of the trough in association with a cold front pushing off the East Coast from Virginia, to Florida, across the Gulf of Mexico to Texas. A 1011mbar low has develop along the front over Central Georgia. When this low moves out to sea, there are possibilities of development.

A broad upper level ridge, centred over Central Mexico extends out over the entire Gulf of Mexico to Florida, Cuba, the Caymans Islands and Honduras/Nicaragua.

A surface high (1015mbars) is cetered near 22N/79W.

A broad upper level trough extends from Bermuda, to the Southernmost Bahama Islands, Hispaniola, Cuba and Jamaica, ending over Central America.
A tropical wave along 76W, is interacting with the trough to help enhance a wide area of scattered showers across the Caribbean Sea and surrounding land masses.

Showers are seen along the ITCZ from Panama, Northern Colombia and Venezuela and Trinidad and Tobago.

Another wave is moving into the Eastern Caribbean Sea, producing isolated showers and T-Storms over Puerto Rico, the Northern Leeward Islands and Windward Islands.

Special From the Eastern Periphery
Major Hurricane Gordon, as of 5 PM AST, was located near 30.2N/54.9W, moving to NE near 12mph. The hurricane is packing winds of 120mph and has a MCP of 955mbars.

As of 5 PM AST, Tropical Storm Helene, was located near 14.2N/37.6W, moving to WNW near 16mph. Helene is packing winds of 45mph and a MCP of 1003mbars.

By Weather456

Tropical Atlantic Today

By: Weather456, 11:25 AM GMT on September 13, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Eastern Periphery………..
Wednesday, September 13, 2006
7:05 AM AST


Special From the Western Atlantic
Florence has become an extra topical gale comprising of the primary low (987mbars), a southern moving cold front to its south and a northern moving warm front to its east.
Places along Nova Scotia and Newfoundland, Canada, will experience gusty winds of up to 40-50knots, high surf, choppy waters and locally heavy rain.

A buoy located near Florence measured a sustain wind of 40knots this morning, other buoys are reporting 25, 30 and 35knot winds.

As of 5am AST, Hurricane Gordon was located near 25.N/57.9W, moving to the NNE near 8knots. The storm has winds of 75mph, with a MCP of 987mbars.

Continue………..
Two tropical waves along 50W and 40W, are associated with little or no convection.

As of 5amAST, Tropical Depression 8 was located 11.9N/26.7W, moving to the west near 14knots. The depression is packing winds of 35mph and a MCP of 1007mbars.(More details alter today)

Another low (1010mbars), located along 7W, is accompanied by isolated moderate convection along the ITCZ.

A large upper level low (TUTT), stands out clearly on water vapor imagery near 35N/45W. Scattered spotty showers accompany the low.

A 1026mbar high dominates most of the Eastern Atlantic with ridging seen across the Atlantic to near Gordon’s location, and gives an idea of where TD8 might end up in the future.

An upper level high dominated much of the eastern Atlantic. This high will help in the intensification of TD8, by providing some low wind shear and divergence aloft.

A cold front extends from near 38N/25W, to the Northern Tip of Portugal, then recurves north to a 973mbar gale near 55N/20W.

The gale is rather intense, with sustain winds of near 50knots. The low is moving to the north into the North Atlantic. The Atlantic Coast of Ireland and The United Kingdom (U.K.) will experience heavy squalls of showers, with gusty winds. Breezy, whitecapping conditions, with moderate choppy seas and very large long ocean swells are also expected, and nearby marine vessels should exercise extreme caution.

The Southern Coast of Iceland, should experience the same and a small craft advisory is in effect for vessels in the vicinity.

Weather456

Tropical Depression 8

By: Weather456, 9:05 PM GMT on September 12, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Tropical Depression 8………..
Tuesday, September 12, 2006
4:47 PM AST


Tropical Depression 8 is located near 12N/23.9W, moving to the W near 15mph. The storm is packing winds of 35mph and a MCP of 1007mbars.

The depression continues to become better organized with banding in almost all quadrants and well-establish convection around the low. The low also has well establish outflow/upper air divergence. If this trend continues, then TD 8 could be named, later tonight or tomorrow.

Surface Observation/Conditions
TD8 is currently moving over 80F degrees water, increasing westward to near 81-82F degrees.

The TD is producing some 5-10ft above normal waves around the Cape Verde Islands.

Scattered showers are also expected over some of the Islands, tonight decreasing as TD8 moves way.

Buoys and Ships
N/A

Forecast
TD8 will continue west along the southern edge of a High in the subtropics, then turn more north around 40-50W, along the westward edge of the ridge, where a wekaness is located.

As, with all tropical systems, so far out there, TD8 moving west across the Atlantic, is not out of the question, so, the best we can do is watch and wait.

TD8 will be under the influence of an Upper level high in the central Atlantic, providing low wind shear and divergence aloft for the system, and intensification is possible.

There is one obstacle in TD8’s future - An area of Saharan Dust to its north and west, but TD8 will most likely find away to overcome it, like Debby and Florence.

TD 8 Possible Tracks


Location of the High Pressure, dry air and low wind shear


Weather456

94L: Our Next Depression?

By: Weather456, 11:02 AM GMT on September 12, 2006

94L Update:
A tropical wave along 22W, accompanied by a 1008mbar low near 13N/20.5W is on the verge of becoming TD8. Quiksat pass, visible imagery loops, 850mb streamline winds, buoys and ships and land-based stations in the Verde islands, suggest 94L has a circulation that either closed or almost closed.

Visible appearance revealed outflow developing to the West, banding in almost every quadrant and well established convection around the low.

Though the low is missing on important ingredient - its winds. The winds in 94L are around 20-25knots, and this is suggested by buoys and stations in the Cape Verde Islands along with quiksat.

The system will be mostly under the influence of an upper air high that will provide low wind shear and divergence aloft leading to intensification.

The low will continue west along the southern periphery of a ridge of high pressure near 25-30W, then turn more north after that, providing that it strengthens.

Today's Tropical and Subtropical Weather Discussion: Florence, Gordon and African Low

By: Weather456, 10:04 PM GMT on September 11, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean and Surrounding Land Masses.............Western Periphery………..
Monday, September 11, 2006
5:37 PM AST


A surface high (1035mbars) is station over Southern Quebec, Canada.

Just on the southern edge of the high is an upper level low spinning over Minnesota, USA. The ULL along with a surface trough in association with a surface low over Wisconsin is generating scattered strong showers and T-Storms over the Mid-West States.

An upper level trough extends from Newfoundland near 50N/60W to new York State near 41N/79W. Numerous “dry showers” accompany this trough.

A cold front extends from New Mexico, across Texas to near 40N/95W, then becomes stationery and criss-crosses the SE United States, ending near the Georgian Coastline. With the exception of a few isolated showers, the front is mainly dry.

An upper level ridge centered over Central Mexico, is enhancing disorganized showers over the Central Gulf of Mexico and the Florida Panhandle.

A weak cyclonic flow is noted on water vapor imagery moving west over the Yucatan Peninsula, accompanied by scattered showers.

Numerous scatted showers are along Central America, Colombia and Venezuela, in association with the ITCZ.

An upper level high centered over the Windward Passage (between Cuba and Hispaniola), is helping to draw some moisture south from Florence and Gordon over the Leeward Islands and Puerto Rico, resulting in isolated showers and T-storms. A tropical wave along 61W, will also add to this moisture.

Tropical Storm Gordon is located near 21.6N/57.3W, moving to the NW near 9mph. The storm is packing winds of 45mph and a MCP of 1003mbars. Gordon will continue NW, then north and could become a hurricane in the long run.

Hurricane Florence is located near 34.4N/64.8W, moving to the NNE near 16mph. The storm is packing winds of 90mph and a MCP of 972mbars.

Hurricane Florence is in the process of being absorbed along a frontal boundary that extends from 32N/70W, to near 50N/62W.
The frontal system is very strong and ships all along the system from Florence to Canada, is reporting 30-35knot winds. One buoy near 49W/49N is reporting winds of 40knots.

African Low
A tropical along 17W, accompanied by a 1008mbar low near 12N/17W, and moderate convection has the potential to develop into a tropical system in upcoming days. Winds around the system is generally light, at around 5-15knots (these were reported by buoys directly under the low). There are no quiksat passes to reveal a possible low level circulation, but visible imagery and 850mbar streamline winds hint a possible circulation.

The system will be mostly under a the influence of an upper air high that will provide low wind shear and divergence aloft leading to intensification.

The low will continue west along the southern periphery of a ridge of high pressure near 25-30W, then turn more north after that, providing that it strengthens.

Weather456

Tropical Depression Seven and Hurricane Florence

By: Weather456, 10:46 AM GMT on September 11, 2006

Good Morningg Everyone:


Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Depression Seven………..
Monday, September 11, 2006
6:14 AM AST


As of 5amAST, Tropical Depression Seven was located at 20.5N/55.1W, moving WNW near 7mph. The storm is packing winds of 35mph and a MCP of 1010mbars.

The depression improved somewhat during the past 12hrs, with some banding developing on the southern eastern quadrant of the system. TD7 continues to main deep convection over the center of circulation and could become TS Gordon, later today or on Tuesday.

The system is very small compared to Florence.

The wind shear from Florence has decrease significantly from 30knots to near 10-15knots this morning, meaning TD7, has a good chance of becoming a strong tropical storm, and dry air is no longer an inhibiting factor for this system.

Surface Observation/Conditions
Though dry air and shear are no longer a problem, sea surface temperatures will be for this system. Florence took some heat content from the ocean as it churned its across the Atlantic, and if TD7, was to follow this path, then there might be some implications. However the system still has a chance because the SST’s in some spots are around 80-81degrees.

Given the size of the system, the wind field remains confined to small area and so are the waves, which are around 10ft above normal.

Buoys and Ships
One buoy (to the east of TD7), measured a pressure of 1016mbars and a south wind of 15knots. The buoy also reported cloudy skies, with light continuous rain.

Another buoy (FQXJ), to the NE of TD7, measured a pressure of 1014.7mbars and a SE wind of 25knots.

The buoys relatively close to TD7 cloud canopy, so that suggest that 30 knot force winds only extends out to a small area.

The buoys also reveals relatively high pressures around the system.

Forecast
TD7, in my opinion, will follow the weakness in the high that Florence created, for at least 48-60hrs. If the high fails to rebuilds after 72hrs, then it's safe to say TD7 will move out to sea (maybe threatening Bermuda), like Florence did.

Given the SST’s, dry air, wind shear and upper air divergence, I would say TD7 reaches at least 50mph, sometime along its track.

Wetaher456

Hurricane Florence
Tropical Depression Six formed from an area of low pressure midway between Africa and the Lesser Antilles on September 3. Initial strengthening of the depression was slow due to shearing wind conditions. Despite the moderate to high wind shear, it strengthened enough to become Tropical Storm Florence on the morning of September 5. After becoming a tropical storm, Florence's wind field began to expand greatly; at one point tropical storm-force winds extended outward up to 405 miles from the center. With a disorganized structure and multiple circulation centers, Florence remained a weak tropical storm for several days, even after external conditions became favorable for strengthening. Around the evening of September 8 it resolved to a single center and steady strengthening resumed - "science had prevailed", as one forecaster remarked[26]. On the morning of September 10, Florence reached hurricane strength. Large swells, rip tide, and undertow have been reported on Bermuda, the Leeward Islands, the Virgin Islands, and Hispaniola.

Current Storm Information
As of 5 a.m. AST (0900 UTC) September 11, Hurricane Florence is located within 20 nautical miles of 31.8°N 66.0°W, about 80 miles (125 km) SSW of Bermuda. Maximum sustained winds are 70 knots (80 mph, 130 km/h), with stronger gusts. Minimum central pressure is 976 mbar (28.82 inches), and the system is moving north near 12 mph (19 km/h). Florence is a large tropical cyclone; tropical storm-force winds currently extend outward up to 290 miles (465 km) from the center while hurricane-force winds extend outward up to 60 miles (95 km) from the center.

Rainfall totals of 5 to 8 inches (125 to 200 mm) are expected over Bermuda, with possible isolated rainfall of up to 10 inches (250 mm). Storm surges of 6 to 8 feet (1.8 to 2.4 metres) are possible along the coast of the island. Florence is expected to remain a Category 1 hurricane as it passes by Bermuda.

Wikipedia, the Free Encyclopedia

Hurricane Florence: Bermuda's Storm

By: Weather456, 12:55 PM GMT on September 10, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Hurricane Florence………..
Sunday, September 10, 2006
8:31 AM AST


As of 8amAST, Hurricane Florence was located at 28N/65.9W, moving NNW near 15mph. The storm is packing winds of 80mph and a MCP of 976mbars.

Tropical Storm Florence, overnight, gained enough organization to be upgraded to a Hurricane earlier this morning. The systems is rather large and well-define cloud structure and circulation. Great outflow is noted on the Eastern quadrant, which suggest that Florence is finally under the upper air anticyclone predicted. Banding clouds are seen in the southern quadrant of the system. Though it might be a little dry air affecting Florence, there seems to be an eye-like feature forming on Florence, that is if Florence has not form an eye already.

Surface Observation/Conditions
Florence is now moving over 80-81F waters.

Waves approaching the Island of Bermuda, will be on the increase today and on Monday. They will range from 15-20ft in some spots. There is a possibility of rip currents and beach erosion caused by coastal flooding in Bermuda. Some of these swells will reach the Eastern Coast of the United Sates also.

Rainfall totals according to the NHC will be around 5 to 8inches and 10inches in isolated spots on Bermuda.

Tropical Storm force winds will begin to affect Bermuda in 12hrs, followed by Hurricane force winds in 12-24hrs.

Buoys and Ships
No ship in there right mind would get close to a hurricane, and there is no buoy close enough.

Land-Based Stations at 8AM AST
Civil Air Terminal, Bermuda
Air Temperature: 27C
Atmospheric Pressure: 1011mbars (Falling)
Winds: East at 37km/hr
Weather Condition: Overcast

Forecast
The storm will continue NNW then N, around the western edge of a ridge of high pressure, then race off to the NE as it gets picked up by a trough.

The system will continue to intensify until it encounters high wind shear and cool waters near 35-40N.

Webcam From Bermuda


Weather456

East Atlantic Tropical and Subtropical Weather Discussion

By: Weather456, 9:33 PM GMT on September 09, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Storm Florence………..
Saturday, September 9, 2006
4:43 PM AST


A tropical wave located along 50W, with a 1013mbar low pressure area near 27N, is accompanied by scattered convection, generate by upper air winds. The wave is located on the outer edges of a dry upper level low that is creating hostile wind shear and very dry air around the low. There are no significant signs of organization at this time, but the low will be watch for development as it continues NW, then N and NNE out to sea in the upcoming days. A ship located to the north of the wave measured an east wind of 20knots a central pressure of 1017mbars.

Most of the North central Atlantic is dominated by surface ridging by a surface high pressure nearly stationary, located near 35N/45W. The rest of the Atlantic west of 50W is dominated by a large upper air high centered mid-way between Bermuda and Nova Scotia, Canada.

A Central Atlantic wave along 36W is associated with moderate isolated convection along the ITCZ.

Another wave accompanied by a 1012mbar low is located along 25W, near the Cape Verde Islands. The wave is accompanied by scattered showers and T-Storms mainly to the south of the low along the ITCZ, which extends as far north as 15N. The northern side of the low is mainly embedded in an area of African Saharan Dust. This wave is also a candidate for potential development next week.

A third low (1010mbar) is stationed near 2W over Burkina Faso, Western Africa.

Much of Western Africa is dominated by an Upper Air Anticyclone.

An Upper level Low is seen spinning nearly stationary in the Eastern Sub-Atlantic. The low is along an upper level trough that extends from 17N to the low at 28N, numerous scatted showers are generated by the low and trough and these might spread into the Madeira Islands.

A cold front extends from 35N/40W to a well define gale low (1000mbars) near 47N/25W. The gale is pretty strong, with associated winds of up to 45knots and gust up 50-55knots. The gale will continue NE towards the Ireland/United Kingdom area brining heavy rains and gust accompanied by high seas. Small craft should exercise caution in areas near the Gale, as a Marine Gale warning is in effect.

A surface high is station of the coast of Portugal.

A weak surface trough extends from Northern Spain, in the Bay of Biscay to southern Ireland. The trough will move into Ireland tonight brining some rain and occasional thundershowers.

A mainly stationary front extends from the gale north into the Norwegian Sea. Strong gusty showers and heavy seas will spread across the Northern United Kingdom, the Faroe Islands and Shetland Islands.

A powerful gale (980mbar seen spinning over Northern Russia, will bring potentially damaging 70knot winds and high snow accumulations to some areas.

A third gale is located east of Greenland, just north of Iceland.

A strong developing gale is moving through the Labrador Sea after emerging off of Newfoundland. The gale is heading for the southern tip of Greenland. Heavy rains and snow accumulation, with very gusty winds and high choppy seas are expected over the area.


Tropical Wave at 25W


East Atlantic Visible Imagery. To the Extreme Left is the Gale Over the Labrador Sea, just south of Greeland, centered is the low at 57N and to the far east is the gale over Russia.

Weather456

A new discussion on Florence will be posted tonight or on Sunday.

Tropical Storm Florence Becoming Better Organized

By: Weather456, 1:39 PM GMT on September 09, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Storm Florence………..
Saturday, September 9, 2006
9:07 AM AST
Updated: 10:40 AM AST


As of 11amAST, Tropical Storm Florence was located at 24.7N/63.7W, moving NW near 13mph. The storm is packing winds of 70mph and a MCP of 992mbars.

Florence has gain increased organization in the overnights and continues to organize at this moment. This morning visible imagery revealed banding developing in almost all quadrants and substantial outflow in the Eastern Semicircle of Florence’s cloud canopy.
The center of Florence (which was also exposed 24hrs ago), is now located in a tightly, well define CDO (Central Dense Overcast).

According to 85H Brightness Temperature Imagery from the Navy, Florence appears to be forming an eye-wall, and could become a hurricane later today or on Sunday.

Surface Observation/Conditions
Florence is now moving over 80-81F waters.

Wave heights of Florence spread out hundred of miles from the center and are in the 20-30ft range. Waves approaching the Northern facing sides of the Leeward Islands and Puerto Rico will be 10ft above normal and increasing as Florence moves north of the area, with a chance of rip currents. These wave will be higher as the approach Bermuda later Today and Sunday.

North Facing Coast of Puerto Rico and the Leeward Islands:
Light winds with a slight chop. Moderate long period swell.
Winds: WNW 7 to 9 knots
Seas: ENE 7 feet at 10 sec.
A small craft advisory is in effect also.

From the NHC 11am Advisory:
IN ADDITION...LARGE OCEAN SWELLS AND DANGEROUS SURF CONDITIONS...
INCLUDING STRONG RIP CURRENTS...ARE ALREADY AFFECTING BERMUDA...AS
WELL AS THE NORTHERN LEEWARD ISLANDS...THE VIRGIN ISLANDS...PUERTO
RICO...HISPANIOLA. THESE CONDITIONS WILL BEGIN TO AFFECT THE TURKS
AND CAICOS...THE BAHAMAS...AND THE EAST COAST OF THE UNITED STATES
OVER THE NEXT DAY OR TWO. SEE STATEMENTS FROM LOCAL WEATHER
SERVICE OFFICES FOR DETAILS ON COASTAL CONDITIONS.

There is also a chance of scattered showers from Florence southern side, given the area of such a large storm.

Bermuda should start to experience tropical storm conditions within 24hrs, and hurricane conditions (if Florence intensifies) in about 36-48hrs.

Buoys and Ships
Ship ZCGH at the SE tip of Florence measured a pressure of 1007mbars and a South wind of 20knots. The ship also reported heavy, intermittent rain.

Forecast
The storm will continue westward around the southern edge of a ridge of high pressure, then turn north around the western edge of the ridge. The turn might be enhance by the progression of an upper level trough draped across the Unites States of America entering the Atlantic. The trough will race her NE toward the Nova Scotia and Newfoundland area of Canada, as an extra topical storm.

Though the United States may be spared from Florence for now, the threat is still there for Bermuda. So Bermudans need to watch the situation carefully.

Florence will continue to be under the influence of an Upper Level High/Anticyclone/Ridge, that will support her until she reaches about 35-40N, where shear will increase.

Tropical Storm Florence:


Weather456

Tropical Storm Florence Tropical Discussion

By: Weather456, 12:05 PM GMT on September 08, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Storm Florence………..
Friday, September 8, 2006
7:50 AM AST
Updated: 6:54 PM AST


As of 5pmAST, Tropical Storm Florence was located at 23.9N/60.1W, moving NW near 15mph. The storm is packing winds of 50mph and a MCP of 1000mbars.

Florence has regained some of her organization after a brush with dry air and cool SST’s yesterday. Today's Visible Imagery showed an improved cloud structure and convection organization; and the latest quiksat wind pass showed a well-define large circulation associated with Florence.
Also seen in the morning hours between 6am and 11am, the clouds can be seen rotating around the LLC.

The Upper Level Low that was channeling dry into Florence’s circulation yesterday has moved further away, allowing much the dry air to be south of her. (See Diagram Below)

Surface Observation/Conditions
Florence is now moving over 80-81F waters. (See Map Below)

Wave heights of Florence spread out hundred of miles from the center and are in the 20-25ft range. Waves approaching the Northern facing sides of the Leeward Islands and Puerto Rico will be 10ft above normal and increasing as Florence moves north of the area. (See Map Below)

There is also a chance of scattered showers from Florence southern side in the Leeward Islands, given the area of such a large storm.

Buoys and Ships
Ship ZCGH in the east side of Florence’s cloud canopy has measured a pressure of 1011.3mbar, moderate intermittent rainfall and a SE wind of 25knots.

Forecast
As the cutoff low begin to move south more, wind shear from the trough should relax allowing some intensification to occur. When Florence moves westward it will become under the influence of an upper level ridge/anticyclone/high near 60-65W, allowing modest intensification to occur and Florence could become a Hurricane, later this week or early next week.

The storm will continue westward around the southern edge of a ridge of high pressure, then turn north around the western edge of the ridge. The turn might be enhance by the progression of an upper level trough draped across the Unites States of America.

Though the United States may be spared from Florence for now, the threat is still there for Bermuda. So Bermudans need to watch the situation carefully.


Water Vapor Imagery


Florence's associated wave heights


Sea Surface Temperatures under Florence

Weather456

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Part Two...Eastern Periphery……
Friday, September 8, 2006
12:05 PM AST


Most of the Central North Atlantic is dominated by surface ridging by a 1027mbar High near 35N/43W.

A tropical wave located along 45W, is accompanied by scattered showers mainly along the ITCZ.

Another tropical wave along 31W is associated with little or no convection due to an area of African Dust that the wave is embedded in.

A third wave that just emerged from the African Coast is accompanied by moderate to strong isolated convection and a 1010mbar low pressure area. A ship (9HOB7) measured a pressure of 1014mbar and a SW wind of 15knots.

A frontal boundary extends from near 35N/32W, to meet a gale low (1000mbars) near 55N. Another front extends from that low to Iceland in the North Atlantic. The front is accompanied by strong intense weather and will bring windy conditions, with choppy seas. A small craft advisory is in effect with long short periods of wind waves. Gale Warnings are in effect for Southern Iceland.

A gale low (1012mbar) located along 45N/18W, moving to the North in the open Atlantic. The gale, along with a High station over Parts of Europe will bring breezy weather of up to 35knots to the Atlantic Coast of France.

A stationary front is draped across parts of Northern Portugal and Spain and is accompanied by squally weather.

An Upper Level trough extends from 30N/30W to near 45N/18W, where a weak Upper Level Low is located in association with the surface gale mentioned earlier.

Another trough extends along 30W from 50N to 62N. This trough will accompany the front that will impact Iceland this weekend.

An Upper Level High dominates most of the Northern Western Africa area.

Weather456

Tropical Storm Florence Tropical Weather Discussion

By: Weather456, 7:24 PM GMT on September 07, 2006

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Tropical Storm Florence………..
Thursday, September 7, 2006
7:21 PM AST


As of 5pmAST, Tropical Storm Florence was located at 20.6N/54.9W, moving WNW near 14mph. The storm is packing winds of 50mph and a MCP of 1000mbars.

This afternoon Florence has gradually build back convection after an encounter with cool SST’s and dry air this morning. This system remains large and irregular with most of the convection to the north and east of the low level center.

The Upper Level Low that cutoff from the trough earlier this week continues to move SW away from Florence, putting Florence is some marginal-low wind shear. Wind shear is only going to continue to improve as Florence becomes under the influence of an Upper Air Anticyclone/Ridge/High pressure, spread across the Western North Atlantic.

Surface Observation/Conditions
In the past 12hrs, Florence has moved over water that are near/below 80dregrees.

Wave heights of Florence spread out hundred of miles from the center and are in the 20-25ft range. Waves approaching the Northern facing sides of the Leeward Islands and Puerto Rico will be 10ft above normal and increasing as Florence moves north of the area.

There is also a chance of scattered showers from Florence southern side, given the area of such a large storm.

Buoys and Ships
Buoy PCBV located inside the intense convection to the east of Florence measured a pressure of 1013mbar and a wind from the SE at 15knots.

Florence continues to move away from Ship MSJZ8. The sip is now reporting winds from the SE at 25knots a pressure of 1010.3mbars.

Forecast
As the cutoff low begin to move south more, wind shear from the trough should relax allowing some intensification to occur. When Florence moves westward it will become under the influence of an upper level ridge/anticyclone/high near 60-65W, allowing modest intensification to occur and Florence could become a Hurricane, later this week.

The storm will continue westward around the southern edge of a ridge of high pressure, then turn north around the western edge of the ridge. The turn might be enhance by the progression of an upper level trough draped across the Unites States of America.

Though the United States may be speared from Florence for now, the threat is still there for Bermuda. So Bermudans need to watch the situation carefully.


Sea Surface Temperatures of the North Atlantic Ocean.


Water Vapour Imagery

Wether456


Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Part One...Western Periphery……
Thursday, September 7, 2006
1:02 PM AST


Surface ridging dominates much of eastern Canada and Continental USA, west of 80W.
The ridging can be contributed to an upper level trough digging down into the U.S., bringing sinking cool air from polar Canada.

At the leading edge of the trough is a stalled out cold front extending from Mexico, through the Gulf of Mexico, over Florida and up the Atlantic Ocean to meet a 1010mbar surface low near 40N/53W. The low will continue NE bringing cloudy skies and chance of showers to parts of Newfoundland and Nova Scotia, Canada.

A 1012mbar low (92L), is located along the frontal boundary near 35N/74W, or just off the Coast of North Carolina. The low is bring cloudy skies and scattered showers to parts of North Carolina, and will spread into Virginia and up the East Coast of the U.S. in time.
Quiksat pass this morning revealed that 92L had a closed circulation, but winds under 25knots (30mph).

An waning Upper level low located in the Bay of Campeche will continue to move west and inland over Mexico. The Upper level low that was located over Mexico and extending into the SW U.S. has been forced out to sea over the Pacific Ocean by the trough mentioned earlier.

Central America has a little break in rain today, with only isolated showers expected, with the exception of Nicaragua and Panama, where a tropical wave interacting with the ITCZ has produce numerous scattered showers over the area. Locally heavy rain of 2+in are excepted.

Showers also extends along the ITCZ, over Northern Colombia, Venezuela and the Windward Islands.

Another tropical wave moving through the Caribbean sea will enhance showers over Hispaniola and Jamaica today.

An Upper level low to the NE of the Leeward Island is helping to enhance showers over the Leeward Islands and Puerto Rico. Showers from Florence during the week is also expected. Also isolated T-Storm will occur in some places.

Weather456

Weather456’s Tropical and Subtropical Weather Discussion for The North Atlantic Ocean.............Part Two...Eastern Periphery……
Thursday, September 7, 2006
3:26 PM AST


A cold front extends from near 43N/40W, to near Iceland, very intense squally weather with some snow accumulations are expected over Iceland. The intense weather will spread into Norway later on Friday and Saturday.

A surface ridge of High pressure centered near 35N/45W dominates most of the North Atlantic from 30W to 70W.

As of 11amAST, Tropical Storm Florence was located at 19.8N/53.4W, moving WNW near 8mph. The storm is packing winds of 50mph and a MCP of 1000mbars. (More Above)

A tropical wave along 41W, with numerous scattered showers seen along the ITCZ.

Another tropical wave is located along 26W. This wave accompanied by little or no convection, due to a large area of Saharan African Dust that sits in the East Atlantic, north of 15N, but east of 40W.

An Upper Level ridge continues to be station in the East Atlantic south of 25N.

Numerous scattered T-Storms over much of the West African Coast due to the ITCZ and a tropical wave that is about to emerge.

A cold front extends from 30N/25W to near 45N/13W, to meet a surface low near 20W. The front will enhance showers and gusty winds over Morocco, Portugal, Spain and France later today. The surface low will become a an Extratropical gale that will impact the U.K. later this week

A stalled out front extends from Southern Europe across the Mediterranean Sea into North Africa (Saharan Area). The front is typical accompanied by bad squally weather.

Weather456

Indian Ocean Tropical and Subtropical Weather Discussion

By: Weather456, 12:52 PM GMT on September 05, 2006

The Indian Ocean will begin to get active starting as of October, so this is a preview of My discussions that I will put on my Blog, during their season from October to April.

Also, discussions on the South Pacifc Ocean will be here.


Weather456’s Tropical and Subtropical Weather Discussion for Entire Indian Ocean, including the Arabian Sea and Bay of Bengal, and surrounding land areas and Madagascar.……..
Tuesday, September 5, 2006
12:13 PM UTC


A surface high is located over Central China accompanied by a front ahead, is creating a south west flow of moisture extending down into Burma and Bangladesh. Strong T-Storms are found along the frontal flow for most of Northern Southeast Asia.

A surface low, more like a tropical depression in the Atlantic basin, is station over Central North India, moving westward. The overland low/depression is accompanied by strong convection, which will spread over Subcontinent today.

Another surface low is located over the Arabian Peninsula, this low is more associated with a heat trough, brought about by continue heating of the land due to cloudless skies. Besides from a few spotty showers, clear skies dominated coastal Afghanistan and Pakistan.

A surface trough located over Ethiopia is accompanied by some spotty showers that will spread across some parts of Somalia and Yemen.

Extensive showers associated with the ITCZ extends across much of the Equatorial Indian Ocean from south of the Arabian Sea, across Southern India and Sri Lanka and into Indonesia and Malaysia, spreading up to Cambodia, Thailand and Vietnam, to meet the front over China discussed above.

An Upper Level high is located over Tanzania.

Two surface Highs dominate the Southern Indian Ocean, separated by a cold front pushing north (opposite from the Northern Hemisphere). The first High is located 30S/45E, and is responsible for bringing dry sinking air resulting in mostly clear skies over much of Southern Africa and Madagascar. The second is located 32S/105E, is doing much of the same but over Western Australia.



Weather456

My Atlantic Tropical Weather Discussion will be on Dr. Master's Blog later today.


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Weather456's Tropical Weather Blog

About Weather456

With a Bachelors Degree in Environmental Sciences (2009), began tracking tropical storms in 2002 and is now a private forecaster.