Scientific Forecaster Discussion
fxus61 kcle 210617
Area forecast discussion
National Weather Service Cleveland Ohio
117 am EST Thu Nov 21 2019
high pressure over the region this evening will move east
towards the East Coast by morning. Meanwhile...low pressure over
the plains will move northeast towards the western lakes. The
low pressure area will move into Michigan by Thursday evening as
the training cold front moves into Northwest Ohio. The front
will cross the region by morning and high pressure will build
over the area by Friday evening. Low pressure will track
northeast through the Ohio Valley Saturday and Saturday night.
Near term /through today/...
there were no impactful changes made to the mid evening forecast
update. Widespread stratus continues to hang on across the
region tonight. Winds will start out this evening light and
variable but become southerly by early Thursday morning and
continue to increase through the morning hours.
quiet weather is expected tonight as high
pressure moves by to the east. A considerable amount of low
clouds will persist tonight under the low level inversion and
some light fog or haze may redevelop especially in the eastern
half of the area.
On Thursday...we can expect a warmer and breezy day with
increasing chances for rain as a cold front approaches the
region towards evening. Lingering low clouds should clear in
the morning but mid and high cloudiness will be overspreading
from the west. 850 mb temperatures warm considerably by morning
and should support high temperatures reaching well into the 50s.
For now we have raised temperatures a bit from the previous
forecast. Showers will likely move into the tol area toward noon
and not into the I-71 corridor until after 20-21z. Showers may
hold off reaching eri to yng until just before 00z.
The cold front will cross the area Thursday night with likely
probability of precipitation in the first part of the night. Probability of precipitation will diminish
especially after midnight in the west and before morning in the
east as drier and cooler air overspreads the region. Only liquid
precipitation is expected with overnight lows of 35-40.
Short term /tonight through Saturday night/...
upper level is quite active heading into the weekend with a vigorous
upper level low pressure system and associated shortwave swinging
through the local area. Large upper level ridge will build east
across the area Saturday and will then quickly retreat to the east
by Sunday. Another fast moving trough will swing east over the
region Sunday. All of these features will result in the first
surface low pressure system exiting to the east toward Maine Friday
followed by a large area of high pressure. Synoptic moisture
associated with the low pressure system will be well northeast of
the forecast area by Friday evening. Some lingering shower activity
will still exist across the southern tier counties and the east
during the afternoon Friday. The surface high will move east across
the area Friday night and be east of the area Saturday. A brief
period of fair weather will be associated with the high. More
moisture associated with the next upper level trough and surface low
pressure will move northeast into the area Saturday. Surface low is
expected to move east across the Ohio Valley and then northeast into
Central Lake Erie by Saturday evening. Some warm air advection will
take place in advance of the low pressure system followed by cold
air advection in the wake of the low Saturday night. 850 mb
temperatures will be between 0 and -4 c Friday morning but mid level
warming will take place as temperatures rise to between 4 and 6
degrees c by Saturday afternoon. As cold air advection returns area
should see a drop of 850 mb temperatures to around -6 c by Sunday.
Surface temperatures will be seasonable.
Long term /Sunday through Wednesday/...
very active weather pattern will continue through this forecast
period as a series of shortwave troughs and alternating ridges moves
east across the area. A weak upper level ridge will be present over
the region Sunday night followed by the upper level shortwave trough
and associated positive vorticity advection. A surface ridge will
also be present at the surface Monday. Amplification of the upper
level ridge will take place along the eastern Seaboard Tuesday night
as somewhat deep digging trough dives into the plains states and
lifts northeast across the Great Lakes Tuesday night into Wednesday.
A fairly strong surface low is progged to move northeast through the
central Great Lakes by Wednesday afternoon. This low will bring
another surge of warmer air Wednesday to the local area followed by
cold frontal passage Wednesday morning. Cold air advection will
take place in the wake of the frontal passage Wednesday afternoon.
Moisture with the actual cold front could be limited. As cold air
advection takes place, there is the possibility for the rain
changing over to snow late Wednesday.
Aviation /06z Thursday through Monday/...
a much more optimistic taf period vs. Previous forecast as
satellite and guidance trends show the stratus all but over the
the terminals tonight, aside for a few hours of lingering
MVFR/VFR stratus at Keri and possibly ktol. High clouds will
continue to overspread the area through the morning, with
lowering ceilings through the day. Rain chances will increase
during the second half of the period from west to east as a cold
front approaches the area. Southerly winds will increase through
the day and become southwest late in the period, with gusts in
the 20 to 30 kt range this afternoon, especially west.
Outlook...non-VFR possible Thursday night and Friday with
a deepening low pressure system is expected to move northeast
across the Great Lakes region on Thursday and Thursday night,
generating a strong wind field across all of the Great Lakes. A
Small Craft Advisory has been issued for all nearshore zones on
Lake Erie starting tomorrow afternoon. Southerly winds of
around 15 to 25 knots will increase to 20 to 25 knots as they
turn to the west and northwest with the cold frontal passage
Thursday night. With the west to northwest winds, significant
wave heights will increase to 6 to 10 feet with occasional waves
as high as 14 feet, especially for the eastern nearshore zones.
In addition to the Small Craft Advisory, a Gale Warning has
been issued for the open waters off of Erie County in
Pennsylvania and Chautauqua County in New York. Sustained west
to northwest winds of up to 35 knots with gusts up to 45 knots
will be possible. Significant wave heights of 9 to 12 feet with
occasional waves up to 15 feet are expected. The best chance
for gales will be between 05z and 10z Friday with sustained
winds quickly diminishing to below 25 knots by 16z Friday.
generally light tranquil winds expected tonight. As next storm
system approaches from the southwest and moves through the
central Great Lakes, winds will begin to increase from the south
tomorrow and continue to increase through the day Thursday. A
cold front will move east across the lake and winds will begin
to shift early Friday morning. Winds will approach gales on Lake
Erie Thursday night and begin to diminish Friday as the low
pressure system pulls out to the northeast. High pressure will
quickly build in from the west Friday night into Saturday. A
ridge of high pressure will build northeast across the region
Sunday causing winds to increase as gradient tightens ahead of
the next low pressure system over central Ontario, Canada
Monday. Cold front will move east across the lake late Monday.
Marine...Small Craft Advisory from 1 PM this afternoon to 7 PM EST
Friday for lez144>149.
Gale Warning from 11 PM this evening to 7 am EST Friday for
Small Craft Advisory from 1 PM this afternoon to 10 am EST
Friday for lez142-143.