Scientific Forecaster Discussion
fxus61 kcle 202037
Area forecast discussion
National Weather Service Cleveland Ohio
337 PM EST Wed Nov 20 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 Thursday night/...
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 /Friday 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 /18z Wednesday through Monday/...
low level temperature inversion and weak solar heating are
inhibiting mixing today so low level cloud cover will persist at
most locations with MVFR/VFR ceilings. 3-5 mile visibility in
br/haze has improved through the morning and most locations have
or will become p6sm for the afternoon. Very light winds will
continue into the evening hours as high pressure slowly moves
east across the region. Patchy light fog or thicker haze may
develop again after sunset so have included some mention of visibility
near 5 sm.
Conditions will improve Thursday morning as the frontal system
to the west draws closer and the pressure gradient increases
which will increase mixing. Low clouds should scatter along
with any haze/fog but high and mid clouds will increase from the
west with the approaching front.
Outlook...non-VFR possible Thursday and Friday with widespread
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