Area Forecast Discussion Issued by NWS Wilmington, OH
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000
FXUS61 KILN 261835
AFDILN
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
235 PM EDT Tue Mar 26 2024
.SYNOPSIS...
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Deep and potent surface low pressure in Wisconsin will continue
to move north into Lake Superior tonight as a cold front sweeps
east into the Ohio Valley. This pattern will continue to bring
gusty winds, showers and a few storms, and cooling temperatures
into Wednesday. High pressure will build into the Mississippi
and Ohio River Valleys on Wednesday and Thursday with dry
weather. A warm front will begin to develop across Indiana and
Ohio on Friday into Saturday as southerly flow transports
moisture into the area, leading to the next chance of showers
and thunderstorms.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Forecast thinking surrounding this evening`s rain chances and
wind/thunderstorm threats/potential has not changed much over
the last 4-6 hours. Clouds have been thick today, and winds very
gusty to 40-45 mph at times, especially on the fringe of rain
areas where evaporation of rain from the mid deck has augmented
wind gusts. Low level jet core has worked north of the forecast
area for the most part, but enough southward extension of 50kts
/h85/ into the area to continue to foster the gust potential.
Per HREF probabilities of 40 mph gusts, should see wind gusts
begin to lose their `edge` from south to north after about 3 or
4 PM. Thus, have the southern/eastern segment of the Special
Weather Statement expiring first at 4 PM, and holding onto to it
through 7 PM for areas of wind-prone west-central Ohio where
HREF probabilities and recent HRRR gust information suggests
gusts will hang on longer. Winds should drop back more
considerably after sunset as a cold front works across the area.
Not much destabilization has taken place in the forecast area as
of 1830Z, and this was expected with the stout cloud cover. We
are starting to see breaks in the clouds to the west, with
temperatures poking up some into the low 60s, and feel this will
happen across the Tri-State area/I-75 corridor between 3PM and
6PM, adding a little instability, pushing MLCAPE toward 300 J/Kg
as dewpoints hold in the lower 50s.Starting to see showers
slowly deepen across central Indiana, though movement has been
more north than east so far. As low level frontogenesis
increases to our west in the later afternoon hours, the showers
should conceal more into a north-south line or broken line of
deeper updrafts /perhaps thunderstorms though that remains in
question if lightning strikes will realized/. Either way - it
won`t really matter on potential impacts due to strong/extreme
low level wind fields. Despite the low level shear vector having
a considerable line-parallel component, there could still be
enough magnitude to vector to allow for shear-dominant line
segments to develop and transport brief strong/severe wind gusts
to the surface via weak/transient mesovortex development, or
just downward momentum transfer and evaporative accelerations.
While overall parameter space - and especially AI/ML guidance of
severe wind/tornado...and HREF calibrated probabilities of
thunder and accumulated 0-3km updraft helicity progs have all
diminished from 00Z to 12Z...the combination of a line of storms
in these very strong wind fields in and of itself suggests a
non-zero severe weather threat. Primary concern would be brief
wind gusts to 55 or 60 mph, and given persistent 0-1km curvature
of the hodograph and effective SRH of ~150 m2/s2, a brief/weak
tornado simply cannot be ruled out. Areas of west central Ohio
are under the greatest relative threat, but a conditional threat
extends southward into southeast Indiana and southwest Ohio for
a few hours. Main window of threat overall is 5PM-8PM, before
activity rapidly weakens.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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Post frontal low clouds should hang tough on Wednesday morning
as westerly winds usher in colder temperatures, but through the
day expect these clouds to scatter out to some degree with
temperatures a few degrees either side of normal.
Better clearing takes hold of the area on Wednesday night, with
temperatures falling below freezing.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
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It`ll likely be a tale of two different weather patterns through the
long term period -- a quiet one Thursday through Friday followed by
a much more unsettled pattern Saturday through the beginning of next
week, the latter of which will bring with it the potential for
several rounds of rain and storms.
For starters, the end of this workweek will close out on a
relatively tranquil note as sfc high pressure builds into the TN Vly
as the pronounced mid/upper level trof finally swings through the
Great Lakes/OH Vly regions. This will set the stage for NW flow to
become established, at least briefly, late Thursday/Thursday night,
with sfc ridging nudging E into the OH Vly as we progress into
Friday/Friday night. Several weak disturbances aloft will eject E
through this flattening flow Thursday night through Friday night,
bringing with it perhaps an increase in cloud cover. However,
despite better moisture transport developing eastward into the area,
LL moisture profiles should remain too meager to allow anything more
than ISO measurable pcpn locally through Friday night.
Near normal temps are on tap Thursday/Thursday night before slightly
warmer air (5-15 degrees above normal) builds in Friday/Friday night.
As we progress into the weekend, a somewhat unsettled weather
pattern looks likely to evolve, with several rounds of rain and/or
storms increasingly likely Saturday through at least Monday night.
While the details of this pattern are still to be resolved, there is
good deterministic and ensemble consensus on a wet pattern
developing this weekend into early next week. Several disturbances
should pivot about the nrn periphery of a midlevel ridge centered
over the nrn Gulf, promoting the development of several weak low
pressure waves/centers moving approximately W to E through the mid
MS and OH Rvr Vlys. The first of these should develop as early as
Saturday morning, with a corresponding enhanced LLJ allowing for
better moisture/mass transport ENE from MO through IL/IN/OH. There
will be a quasi-oscillating boundary that will become established
within the region for the better part of ~3 days, which will serve
as a focus for renewed/additional rounds of rain/storms each day
Saturday, Sunday, and Monday.
While ensemble guidance points toward higher probs of more
widespread rain/storm activity Saturday near/N of I-70, PoPs have
been broad-brushed at these time ranges to include a chance of
precip just about everywhere. This initial wave, upon its departure
Saturday night, may act to shift the aforementioned boundary S to
closer to/S of the OH Rvr as drier air briefly builds in behind the
first sfc wave Saturday night/early Sunday. However, renewed
convective development is likely on Sunday as additional S/W energy
pivots around the broad-scale ridge axis and into the OH Vly. This
will coincide with more aggressive moisture transport back N into
the region, with PWAT anomalies exceeding 150% of normal by Sunday
night. This should allow for another round of rain/storms (with some
low-end instby being shown on much of the prevailing guidance).
We should see a northward pivot in the boundary once again Sunday
night into Monday, with more of the local area becoming situated
squarely in the warm sector of the eastward-moving system, which
should eject through the central plains into the mid MS Rvr Vly by
Monday afternoon. Renewed rain/storm chances will occur once again
late Monday/Monday night with the better forcing and additional lift
spreading E ahead of/along the front, with drier conditions finally
returning by later Tuesday.
There are several items to watch regarding the pattern this weekend
into early next week -- most notably the repeated rounds of rain and
whether the heaviest activity from each "round" moves over the same
areas more than once. Still a bit too far out to isolate one
specific favored area/corridor for heavy rain, but it is mentioned
here for general awareness purposes, especially considering the
cumulative effect as we progress into Monday/Monday night. The other
item will be the potential for a few strong/severe storms late
Monday/Monday night. The overall setup, from a pattern recognition
perspective, certainly suggests that severe storms may develop
in/near the local area if the necessary ingredients come together.
And if a more wide-open warm sector is able to develop Monday
afternoon/evening, allowing for a better LL thermodynamic setup,
amidst seasonably strong deep-layer wind fields, a few strong to
severe storms could evolve. However, even with this said, there are
too many uncertainties in time and space at this juncture to include
in the HWO.-- End Changed Discussion --
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Plenty of aviation concerns with this TAF cycle as detailed
below...
1) Surface winds - have been strong out of the SSE this morning
with frequent gusts to around 35kts, locally higher. Short term
model guidance suggests that - while in general winds will start
to slowly decrease from south to north as the low level jet
axis shifts north, it will still remain very windy through the
afternoon as southerly winds continue 15 to 25kts, with gusts to
35kts at times. First to decrease will likely be CVG/LUK with
gusts losing some magnitude by later this afternoon, and
similarly ILN/LCK/CMH a few hours later. DAY may continue to
gust strongly into early evening. After sunset, winds will
diminish but still be gusty, turning southwest, and temporarily
west behind the cold front crossing the area. Several hours
after frontal passage, as winds weaken back < 10kts they will
drift back to southwesterly and then increase to around 10kts
after sunrise as they try to shift back to the west.
2) Low clouds - ceilings have been a mix of MVFR/VFR this
morning and will stay that this afternoon. Some light rain
moving north from Kentucky this afternoon may keep MVFR ceilings
in play for ILN/LCK/CMH a little longer than points west, which
should slowly ascend into VFR category through the night outside
of showers/storms. However, in the wake of the cold front,
cooling will lower cloud bases back into a mix of MVFR and VFR
on Tuesday morning.
3) Thunderstorms - expect scattered showers to continue to
slowly develop and congeal into a line or a broken line of
showers (with isolated lightning strikes) as it crosses the
terminals in the 23Z-03Z timeframe from west to east. While
precipitation is rather certain as this line works west to east
across the area, the presence of thunder is not owing to weak
instability, and thus have kept predominant SHRA with VCTS for
right now.
4) Visibilities - only in the heaviest part of the line of
showers are visibilities expected to drop, but there is
uncertainty right now on low it could go, so for right now have
focused any /MVFR/ visibility restrictions on the northern TAF
sites with the showers where they are more certain, and are more
likely to be heavier.
OUTLOOK...MVFR conditions are possible on Saturday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Binau
NEAR TERM...Binau
SHORT TERM...Binau
LONG TERM...KC
AVIATION...Binau