Caribbean Disturbance 92L Moving Over the Yucatan; Erin Forms Off of Africa

By: Dr. Jeff Masters , 2:40 PM GMT on August 15, 2013

The tropical wave in the Western Caribbean near the Yucatan Peninsula (92L) is growing more organized this morning, after an evening when it lost most of its heavy thunderstorm activity. Satellite loops show a modest-sized area of heavy thunderstorms that are increasing in intensity and areal coverage, but there are a no signs of a surface circulation. Winds at surface stations in the Western Caribbean also do not show a surface circulation. The highest surface wind reports this Thursday morning were at Western Caribbean buoy 42056 about 140 miles east southeast of Cozumel, which had east winds of 25 mph, gusting to 34 mph, at 10 am EDT. Wind shear is a moderate 10 - 20 knots over the the wave, which should allow slow development today until its west-northwest movement at 10 - 15 mph carries it over the Yucatan Peninsula Thursday afternoon. Four hurricane hunter flights were scheduled to fly into 92L today--an Air Force mission tasked to provide a center fix early this afternoon, two NOAA P-3 missions aimed at collecting real-time radar data to feed into the HWRF model, and a flight by the NOAA jet to collect dropsonde data around the periphery of 92L. However, all of these flights were cancelled, given that 92L did not organize as much as much as it could have.


Figure 1. MODIS satellite image of Invest 92L taken at 12:30 pm EDT Thursday August 15, 2013. Image credit: NASA.

Forecast for 92L
92L will trek across the Yucatan Peninsula Thursday evening and arrive in the Southern Gulf of Mexico on Friday, when it will have the opportunity to strengthen. The 06Z Thursday SHIPS model forecast predicts that 92L will remain in an area of low to moderate wind shear through Saturday, and ocean temperatures will be a favorable 29 - 30°C. The topography of the Southern Gulf of Mexico's Bay of Campeche can aid in getting a storm spinning more readily, but 92L may be far enough north that this influence will be negligible. Given all these factors, 92L should be able to become at least a tropical depression by Saturday, A trough of low pressure over the northern Gulf of Mexico will dip down by Saturday evening over the Central Gulf of Mexico, potentially increasing wind shear to a high 20 - 30 knots, stalling any further intensification. This trough may also be able to pull the storm northwards to a landfall between Eastern Louisiana and the Florida Panhandle, as the 00Z Thursday run of the European model is suggesting. This would bring a plenty of tropical moisture into the Southeast U.S., resulting in a large area of 4+" of rain. However, the other models show a more westerly track for 92L, with landfalls possible in Texas or Mexico south of the Texas border, and there is high uncertainty where 92L may go once it enters the Gulf of Mexico. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave 92L a 50% of developing by Saturday, and a 60% chance of developing by Tuesday.


Figure 2. MODIS satellite image of Tropical Storm Erin taken at 10:30 am EDT Thursday August 15, 2013. At the time, Erin had maximum sustained winds of 40 mph. Image credit: NASA.

Tropical Storm Erin
The season's fifth named storm of the year, Tropical Storm Erin, has formed over the far Eastern Atlantic off the coast of Africa. Erin is over warm waters of 27°C and is under a moderate 10 - 15 knots of wind shear, which should allow continued development today and Friday. Erin is a small storm, as seen on satellite loops. The 12Z Thursday SHIPS model forecast predicts that wind shear will be low to moderate for the next five days, which favors development. However, the waters beneath Erin will steadily cool to a marginal 26°C by Friday, and the atmosphere will steadily get drier, as the storm encounters the Saharan Air Layer (SAL), discouraging development. Erin's west-northwest motion will cut the storm off on Sunday from a moist source of air to its south--the semi-permanent band of tropical thunderstorms called the ITCZ (Inter-Tropical Convergence Zone.) The storm should weaken beginning on Sunday, which would result in Erin turning more to the west as the east-to-west blowing surface trade winds begin to dominate the steering of the shallower storm. We may see a situation like occurred for Tropical Storm Dorian in late July--intensification to a 60 mph tropical storm, followed by a slow decay and dissipation. The latest run of the GFS model calls for Erin to dissipate well before reaching the Lesser Antilles Islands.

Typhoon Utor dissipates
Typhoon Utor has dissipated after hitting Southeast China about 150 miles southwest of Hong Kong on Wednesday as a Category 1 storm with 90 mph winds. The typhoon is being blamed for 1 death in China, and sank a 21-person cargo ship off the coast. In the Philippines, where Utor hit as a Category 4 storm with 140 mph winds on Monday, 8 deaths are being blamed on the storm, and damage is estimated at $20 million.

Jeff Masters


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

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I see it coming yesterday and everyone bash and laugh at me

92l just didn't do anything even when it had great conditions to work with
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Quoting 33. moonlightcowboy:
It never ceases to confound me that those who never contribute anything resourceful or informative to the blog, always seem to be the very ones that offer only punitive remorse and disdain to those that do, regardless of whether those contributions were wrong or right - the results are always beneficial.

The object is to learn and participate positively. And, if one can hardly offer anything along those lines in a civil, community-type manner, those type of folks would serve themselves, and certainly the community, better if they just kept their unkind, demeaning and their obviously quite troubled inner-self expressed outwardly off the blog.

Unfortunately, it's not difficult to recognize these types. It's the same few I've watched for years with the same similar kind of attitude and response each and every time. My ignore list continues to grow. ;)



Great post, moonlightcowboy. Thanks for this.
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Quoting 16. HurricaneCamille:
92l poof

what a bust hahaha
And I thought it might be another Camille!
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Quoting 22. TampaSpin:
Not even clost to being accurate.


Agreed, Tim. I really like the CIMSS site and the various, diverse charting, but it never seems to even be close really to real time, unfortunately. It's a great site with great information, however.
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Quoting 29. LargoFl:
12z Nam is finished...................

Says 57 hrs. Not complete yet. Goes out to 84 hrs.
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Quoting 25. CybrTeddy:
No mention of possible development behind Erin? Otherwise, awesome update as usual Dr. Masters. We really need the fresh blog.
I like the updates its like a fresh new start
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Quoting 31. TropicalAnalystwx13:
90C is likely a tropical cyclone.

Pewa or td 1c
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Firing some deep convection as expected for DMAX, but looking a bit disorganized at this time.

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despite models killing off erin, i suspect she will be a problem down the road
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It never ceases to confound me that those who never contribute anything resourceful or informative to the blog, always seem to be the very ones that offer only punitive remorse and disdain to those that do. The thing is, regardless of whether the contributions are wrong or right, the results are always beneficial.

The object is to learn and participate positively. And, if one can hardly offer anything along those lines in a civil, community-type manner, those type of folks would serve themselves, and certainly the community, better if they just kept their unkind, demeaning and their obviously quite troubled inner-self expressed outwardly off the blog.

Fortunately, it's not difficult to recognize these types. It's the same few I've watched for years with the same similar kind of attitude and response each and every time. My ignore list continues to grow. ;)

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thanks for update doc

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90C is likely a tropical cyclone.

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Plan of the Day

000
NOUS42 KNHC 141729
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0130 PM EDT WED 14 AUGUST 2013
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 15/1100Z TO 16/1100Z AUGUST 2013
TCPOD NUMBER.....13-074 AMENDMENT

I. ATLANTIC REQUIREMENTS......MISSIONS ADDED
1. SUSPECT AREA - NEAR YUCATAN PENINISULA
FIGHT ONE -- TEAL 70 FLIGHT TWO -- NOAA 49
A. 15/1700Z A. 16/0000Z
B. AFXXX 01BBA INVEST B. NOAA9 02BBA SURV
C. 15/1430Z C. 15/1730Z
D. 19.0N 87.0W D. NA
E. 15/1630Z TO 15/2000Z E. NA
F. SFC TO 15,000 FT F. 41,000 TO 45,000 FT

FLIGHT THREE -- NOAA 43 FLIGHT FOUR -- NOAA 42
A. 15/2100Z A. 16/0900Z
B. NOAA3 03BBA RADAR B. NOAA2 O405A CYCLONE
C. 15/1800Z C. 16/0600Z
D. 19.8N 87.8W D. 21.6N 89.1W
E. 15/2000Z TO 16/0030Z E. 16/0730Z TO 16/1200Z
F. SFC TO 15,000 FT F. SFC TO 15,000 FT

FLIGHT FIVE -- TEAL 71
A. 16/1200Z, 1800Z
B. AFXXX 0504A CYCLONE
C. 16/0930Z
D. 22.0N 89.5W
E. 16/1130Z TO 16/1800Z
F. SFC TO 15,000 FT

2. OUTLOOK FOR SUCCEEDING DAY:
A. CONTINUE 6-HRLY FIXES IF SYSTEM REMAINS A THREAT.
B. A POSSIBLE G-IV MISSION AT 16/1730Z.
C. ANOTHER P-3 MISSION AT 16/1800Z

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.

$$
JWP

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12z Nam is finished...................
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Meteorologist Tim Buckley
51 minutes ago
Coolest high temp ever for this date is 76°, and I DON'T think we'll get that warm today. Clouds/rain should help us set a new record.
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Quoting 16. HurricaneCamille:
92l poof

what a bust hahaha
for now but really never write anything off cause there is always a chance they could do something

hopefully nothing
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Apparently recon's headed out:

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No mention of possible development behind Erin? Otherwise, awesome update as usual Dr. Masters. We really need the fresh blog.
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Quoting 2. SouthernIllinois:
Doc! Thanks! Hey how that weather in Ann Arbor treating you?? Been chilly here!! Nights are like the low 50's Doc Master's. That window opening weather and it's the middle of August in Southern Illinois. What is UP WITH THAT JEFF!!!!????

What does this mean for Autumn. For winter? Is this a harbinger?? OMG it is cold down here for this time of year. GOODNESS!!!!

Natalie :)


What I wouldn't give for some 50 degree nights :) We had a "cold front" come down last night dropping it from the 100s to the upper 80s so I guess I can't really complain.
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Great blog doc!
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I wanted to repost this from the last blog....


LOOK at the Shear on 92L....Just shows how hard SHEAR is to forecast at 12hrs ,,,,48hrs is like throwing darts....LOOK at these shear maps....Not even clost to being accurate.





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Not sure if there is a closed low, but there are two land stations reporting westerly winds south of 92L.
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moisture clouds are starting to form here on the gulf coast over me,I am waiting to see the sea breeze start to fire up..could be interesting around here later on.
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Quoting 3799. GrandCaymanMed:
For folks on the Gulf Coast, it is very good news that the ULL over the Gulf ripped 92L into 2 pieces, one headed north into FL and another west. This was depicted by the GFS a few runs back. In any case, I am HAPPY my forecast yesterday for 92L to streng materialize.

If then, move north in response to a trough and get into the GOM to attain hurricane strength will not it were not for the ULL over the GOM, 92L could easily have been a significant and dangerous hurricane headed for the Gulf Coast, something that would be very bad news.

Hopefully the remnant moisture from 92L can give parts of Texas some much needed rain in 3-5 days.

From last blog: maybe so but the real piece will be in sw gulf and commence fire there.
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Quoting 1. allancalderini:
Thanks Dr.Masters.


Already RIPin' Erin...OK. What about the blob in front of Erin?
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92l poof

what a bust hahaha
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Thanks for the new blog Doc! Sure hope Texas can get some rain out of 92L
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Quoting 2. SouthernIllinois:
Doc! Thanks! Hey how that weather in Ann Arbor treating you?? Been chilly here!! Nights are like the low 50's Doc Master's. That window opening weather and it's the middle of August in Southern Illinois. What is UP WITH THAT JEFF!!!!????

What does this mean for Autumn. For winter? Is this a harbinger?? OMG it is cold down here for this time of year. GOODNESS!!!!

Natalie :)


blah blah blah China record heat blah blah ice melting blah blah blah CO2
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Repost but with some updates:

For folks on the Gulf Coast, it is very good news that the ULL over the Gulf ripped 92L into 2 pieces, one headed north into FL and another west. This was depicted by the GFS a few runs back. In any case, I am HAPPY my forecast yesterday for 92L to strengthen, move north in response to a trough and get into the GOM to attain hurricane strength will not materialize.

If it were not for the ULL over the GOM, 92L could easily have been a significant and dangerous hurricane headed for the Gulf Coast, something that would be very bad news.

Hopefully the remnant moisture from 92L can give parts of Texas some much needed rain in 3-5 days. With that said, there is some chance of intensification in the BOC to a tropical storm, so based on these parameters (a trough pulling it north and then a ridge building back in), south Texas and northern Mexico may see heavy rain from a system that may be as weak as a tropical wave or as strong as a tropical storm.
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Carryover from last blog:

I think some people may be missing out on the fact that yesterday at this time the wave was in an area where the trade winds were blocked by the lower level ridge (155 iso in this:


pic, GEFS analysis for 6z yesterday); Notice the trade wind flow sharply lower in velocity on the wind barbs.

This was causing additional low level convergence along the wave axis and supported decent convection.

On the 6z GEFS analysis today, a much different look to the lower level flow is seen.



Notice the same 155 iso now pulled off to the N and the trade flow no longer being piled up in the W. Caribbean.

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BULLETIN
TROPICAL STORM ERIN ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052013
1100 AM AST THU AUG 15 2013

...ERIN MOVING AWAY FROM THE CAPE VERDE ISLANDS...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.4N 26.5W
ABOUT 115 MI...185 KM WSW OF BRAVA IN THE CAPE VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES





TROPICAL STORM ERIN DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052013
1100 AM AST THU AUG 15 2013

THE SATELLITE PRESENTATION OF THE CYCLONE HAS CONTINUED TO IMPROVE
OVER THE PAST FEW HOURS. INFRARED IMAGERY SHOWS VERY COLD CLOUD
TOPS SITUATED NEAR AND TO THE SOUTH OF THE ESTIMATED CENTER
POSITION...WITH A SMALL BANDING FEATURE EXTENDING TO THE SOUTHWEST.
THE INITIAL INTENSITY OF 35 KT IS SUPPORTED BY A BLEND OF THE
LATEST OBJECTIVE AND SUBJECTIVE DVORAK ESTIMATES AND A 1102 UTC
ASCAT-A PASS THAT SHOWED WINDS OF 32 KT. ERIN IS EXPECTED TO BE IN
AN ENVIRONMENT THAT SUPPORTS SOME STRENGTHENING DURING THE NEXT
COUPLE OF DAYS WITH SSTS OF 26-27C...LOW SHEAR...AND A MOIST
ENVIRONMENT. BY DAY 3...THE SYSTEM WILL BE MOVING INTO A DRIER AND
MORE STABLE ATMOSPHERIC ENVIRONMENT...WHICH SHOULD RESULT IN
WEAKENING. THE GLOBAL MODELS AND THE HWRF SHOW A WEAK OR
DISSIPATING SYSTEM BY DAY 5...HOWEVER THE SHIPS AND LGEM SHOW
LITTLE CHANGE IN INTENSITY OR EVEN STRENGTHENING. THE OFFICIAL
FORECAST LEANS A LITTLE TOWARD THE WEAKER SOLUTION AT DAYS 4 AND 5.

THE AFOREMENTIONED ASCAT PASS WAS ALSO HELPFUL IN LOCATING THE
CENTER OF ERIN...WHICH IS A LITTLE SOUTH AND WEST OF PREVIOUS
ESTIMATES. BASED ON A SOUTHWESTWARD ADJUSTMENT OF THE CENTER
POSITION THE INITIAL MOTION ESTIMATE IS 285/13. ERIN IS CURRENTLY
BEING STEERED BY A NARROW SUBTROPICAL RIDGE TO ITS NORTH...AND THE
GUIDANCE IS IN GOOD AGREEMENT ON THIS MOTION CONTINUING FOR THE
NEXT COUPLE OF DAYS. BY DAY 3...THE SPREAD IN THE GUIDANCE
INCREASES. ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE THE GFDL...
GFDL ENSEMBLE MEAN...ECMWF AND UKMET SHOW A NORTHWESTWARD OR
WEST-NORTHWESTWARD MOTION. THE FIM...GFS...GFS ENSEMBLE MEAN AND
HWRF ALL SHOW A WESTWARD TRACK...CONSISTENT WITH A SHALLOWER SYSTEM
BEING STEERED BY THE LOW-LEVEL FLOW. THE NHC FORECAST AT DAYS 3
THROUGH 5 CONTINUES TO FOLLOW THIS SOUTHERN CAMP OF MODELS AND IS
LARGELY AN UPDATE OF THE PREVIOUS NHC TRACK.


FORECAST POSITIONS AND MAX WINDS

INIT 15/1500Z 14.4N 26.5W 35 KT 40 MPH
12H 16/0000Z 15.0N 28.6W 40 KT 45 MPH
24H 16/1200Z 15.7N 31.2W 45 KT 50 MPH
36H 17/0000Z 16.7N 33.5W 45 KT 50 MPH
48H 17/1200Z 17.4N 35.8W 50 KT 60 MPH
72H 18/1200Z 18.0N 40.0W 50 KT 60 MPH
96H 19/1200Z 18.0N 44.5W 45 KT 50 MPH
120H 20/1200Z 18.0N 49.0W 35 KT 40 MPH

$$
FORECASTER BRENNAN
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Thank you Dr. Masters!
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Thank you Dr. Masters! I had a feeling a new entry would pop up soon
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Thanks for the Update :o0

Taco :o)
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Thanks.
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Thanks Dr. Masters!

Erin remains at 40mph at 11am advisory.

...ERIN MOVING AWAY FROM THE CAPE VERDE ISLANDS...

11:00 AM AST Thu Aug 15
Location: 14.4N 26.5W
Moving: WNW at 15 mph
Min pressure: 1006 mb
Max sustained: 40 mph
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Thanks Dr.Masters.
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather