Area Forecast Discussion Issued by NWS Wilmington, OH
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000
FXUS61 KILN 140604
AFDILN
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
204 AM EDT Thu Mar 14 2024
.SYNOPSIS...
More warm weather and gusty winds are likely on Thursday ahead
of a low pressure and cold front which will cross the area on
Friday. With the gusty winds will come higher moisture, and
shower and thunderstorm chances will increase with most areas
seeing rain at some point from Thursday into Friday. Behind the
front the airmass will cool considerably as high pressure builds
into the area. Secondary cold fronts will swing through the
Great Lakes during the weekend into early next week, reinforcing
the cooler air and continuing the mostly dry weather from the
upcoming weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
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The overnight period is starting with quiet conditions, but a
turn to much more active weather will begin several hours from
now. A surface warm front extends west-to-east across far
northern Indiana and Ohio, and there is a secondary surface
boundary also noted in observations in southern Indiana. The
main issue overnight will be warm frontal processes aloft, with
a robust feed of theta-e at 925mb on SW flow. Isolated
convection is currently ongoing near the IL/IN border, and a
blossoming in coverage is expected in response to the increasing
moisture. This will bring showers and storms into the western
and northwestern sections of the ILN CWA generally after 08Z,
then progressing eastward across the northern sections of the
forecast area through 14Z. There are doubts about the southern
extent of this activity, and if the Tri-State Cincinnati area or
parts of southern Ohio / northeast Kentucky will even get any
precipitation from this first round. Confidence is highest for
areas further north and west. Model soundings suggest a healthy
near-surface inversion, but steep lapse rates and some deep
layer shear would suggest small hail could accompany the
elevated storms early this coming morning.
There remains considerable uncertainty with storm mode / timing
for the rest of tomorrow and tomorrow night, but by afternoon
and evening, the parameter space appears favorable for some
severe weather. The upcoming midnight shift will have a full
suite of 00Z data available to help assess this potential.
Previous discussion > Primary concern tonight will be with
shower and thunderstorm chances/coverage.
Ample sunshine and warm breezes across the ILN CWA early this
afternoon, and dew points have held steady in the lower 40s
which is keeping humidities in the 30-40% range, so with the
more sporadic wind gusts vs yesterday`s more widespread and
stronger winds, did not feel a need to message any fire weather
concerns into this evening on a larger scale.
After midnight, increasing theta-e advection aloft will drive
the potential for an arc of showers and perhaps a few elevated
storms from southwest to northeast across mainly the northwest
half of the ILN forecast area. This is not a high confidence
signal across the suite of convective allowing and global
ensemble members, however, thus chances along I-71 are
maintained in the 20-40% range. A better /spatial and forcing/
signal exists for showers and thunderstorms to develop tonight
in Illinois and cross Indiana on an ENE trajectory toward the
northwestern third of the ILN forecast area, arriving in the
hours before or just after sunrise in west central Ohio. Likely
elevated in nature, these are unlikely to be strong / severe but
do warrant the maintenance of higher rain chances that were
ongoing in the forecast already across west central Ohio in the
10Z-12Z timeframe.-- End Changed Discussion --
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.SHORT TERM /FRIDAY/...
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Expect the cluster of showers/storms mentioned above entering
west central Ohio around sunrise to continue on a east-northeast
trajectory toward central Ohio during the morning hours, but it
is at this point where the forecast begins to lose some degree
of certainty, and how long these hold together downstream over
central Ohio (or perhaps moving more into northern Ohio) remains
to be seen.
In general, as a potent mid level speed max ejects northeast
owing to height falls digging into the Rockies and with heights
rising downstream over the Ohio Valley, activity should have the
propensity to either weaken/diminish over central Ohio or lift
more north into northern Ohio as forcing diminishes immediately
over the ILN CWA, leaving somewhat of an open-warm- sector lull
across much of our forecast area from late morning into early
mid afternoon.
That being said, as this speed max and embedded shortwave
arrives into Indiana/Michigan during the afternoon, expect a
renewed storm cluster/MCS to develop across ILN/IN and move
rapidly toward MI/OH. There are some convective-allowing
solutions which develop a rather robust MCS that rides along the
synoptic warm front lying either just north of our area or
across our northern tier, taking on linear/bowing
characteristics. Some solutions ride this activity well north of
our area, but there is a general / overarching trend in most
guidance /backed up by machine learning probabilities based on
GEFS/HREF/ that our northern half of our forecast area is under
a threat for severe storms tomorrow that could - if things come
together - exceed current Level 1 /Marginal Risk/ categories
from the SPC. But the uncertainty tied to the coverage / track
of this cluster of storms, coupled with marginal thermodynamics
are likely playing a role here. What we do know is that low
level and deep level shear /hodograph curvature/ is rather
optimal for storm longevity and organization for any MCS or
discrete cells which may form, but there is some concern for the
level of moistening that can be maintained in an open warm
sector scenario. If dewpoints can`t ascend past the mid 50s -
which is being hinted by some of the CAMS which have handled low
level moisture more optimally this week - overall convection
may struggle to maintain intensity outside a more optimal setup
with regards to shear/warm front/synoptic forcing with the jet
streak. This situation will need to be watched closely, and if a
more robust storm cluster can get going in this kind of shear
environment across the northern half of the ILN forecast area,
all modes of severe weather including a tornado or two will be
in play.
After the potential afternoon-early evening storm threats, we
are not out of the woods as the passing jet streak will begin to
push low pressure and associated cold front southeast toward
our area later Thursday night into Friday morning, and another
wave of storms /likely focused more to the southwest of the ILN
CWA/ may impact areas along the Ohio River and points south
later in the night. While severe threats with this activity
would be less, there would still be ample low level shear in
play,as despite the more reduced instability by coming through
at such a late time of night.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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Showers and a chance of thunderstorms will continue into Friday
morning, but should be tapering off from the northwest through
late morning and into the afternoon as the cold front moves
southeast of our area. In the developing CAA behind the front,
highs on Friday will range from the mid 50 northwest to the mid
60s in the southeast. Surface high pressure will build briefly
into the lower Ohio and Tennessee Valleys Friday night into
Saturday. This will provide for drier conditions with highs on
Saturday in the mid 50s to lower 60s.
Mid level short wave energy, embedded in a broader upper level
trough, will drop down across the Great Lakes on Sunday, leading
to the potential for a few rain showers across our area.
Temperatures will continue to cool with highs on Sunday in the
mid 40s to mid 50s. A somewhat stronger secondary short wave
will rotate through the base of the trough and across the lower
Great Lakes and upper Ohio Valley on Monday. This will bring a
chance for mainly snow showers to the region as high on Monday
will only be in the upper 30s to lower 40s.
The upper level trough will shift off to the east and surface
high pressure will build into the region through mid week. This
will lead to drier conditions and slowly moderating
temperatures. Highs on Tuesday will be mostly in the 40s with
highs on Wednesday in the upper 40s to mid 50s.-- End Changed Discussion --
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
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Low level moist ascent with a developing warm front will bring
a threat of showers and thunderstorms through sunrise, mainly
near the KDAY terminal and northwest of the KCMH/KLCK terminals.
VFR conditions will persist outside of convection, but lower
MVFR visibilities, isolated IFR visibilities will be possible in
storms.
For later today, from mid morning into mid afternoon, models
continue to advertise the potential for a convective line
segment to traverse from west to east and affecting mainly
northern terminals. MVFR ceilings and MVFR/IFR visibilities will
be possible in stronger storms. Winds will increase from the
southwest between 10 and 15 knots with gusts up to 25 knots
possible.
For tonight, showers and thunderstorms will increase in
coverage from northwest to southeast as a cold front slips into
the region from the northwest. Low level convergence and upper
level support will provide the necessary lift for the more
widespread convection. Again, lower conditions will be possible
in the stronger storms (MVFR/IFR). More predominate lower
conditions will arrive behind the slow-moving cold front toward
12Z Friday.
OUTLOOK...MVFR to IFR conditions are likely Friday with a
lingering chance of thunderstorms over southern locations. MVFR
conditions possible Saturday night and again on Monday.-- End Changed Discussion --
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Binau
NEAR TERM...Binau/Hatzos
SHORT TERM...Binau
LONG TERM...Binau/JGL
AVIATION...Hickman