ILN issues Area Forecast Discussion (AFD) at Dec 15, 6:17 AM EST
249
FXUS61 KILN 151117
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
617 AM EST Sun Dec 15 2024
.SYNOPSIS...
A mild and soggy weather pattern will prevail through the first
half of the upcoming week, with drier and colder conditions
expected toward the end of the week. Until then, several systems
will bring widespread steady rain to the region, with above
normal temperatures through midweek.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Widespread steady rain has overspread the ILN FA this morning,
courtesy of large-scale forcing and robust moisture transport
and moisture/mass convergence on the nose of a 40-50kt H8 LLJ.
This rain will continue through daybreak before becoming more
scattered in nature toward 15z and beyond as the lift weakens.
In fact, latest indications show mainly ISO SHRA lingering in
the area by mid afternoon, particularly across the Tri-State
into SE IN where drier conditions should evolve late in the day.
Total rainfall through mid/late afternoon should generally be
on the order of 1/2 to 3/4 of an inch, with rainfall rates of
generally a tenth of an inch or less per hour through sunrise.
Although "drier" conditions will evolve for this evening,
sufficient LL moisture will remain entrenched locally amidst
lingering subtle lift, which may lead to the development of
some patchy drizzle this evening into tonight. At the very
least, ample LL saturation will yield low ceilings and some
misty conditions this evening/tonight.
Temperatures this afternoon will top out in the upper 40s to
lower 50s and shouldn't dip too much tonight, perhaps only a few
degrees.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
A brief respite will evolve tonight as midlevel ridging moves in,
although patchy fog and/or drizzle should develop across at
least parts of the area. The main item of interest for the short
term period is going to be the arrival of another round of
rain, this time during the daytime Monday.
Following the departure of the weakening closed low to the E
tonight, a deepening/digging trof in the upper midwest will put
the OH Vly in a favorable location for increasing large-scale
ascent/forcing with sufficient moisture/moisture transport NE
into the region on Monday. Although the next round of rain will
be fairly progressive, some brief moderate to locally heavy
rain rates will be possible, particularly near/S of the I-71
corridor. The activity on Monday should be more showery in
nature, with an initial surge of widespread showers after
daybreak into mid afternoon, with additional SCT activity
focusing along the eastward-advancing front during the evening.
Latest guidance, including ensemble datasets, suggest only
marginal potential for near/greater than 1" of rain on Monday
with greatest probs (still generally <20%) near/S of I-71,
particularly within a corridor near Switzerland Co IN to Ross Co
OH and point further S. Of course, the prospect of an inch of
rain typically wouldn't raise any eyebrows, but it will be
coming immediately on the heels of the widespread 1/2 to 3/4 of
an inch today, so soils are expected to become increasingly
soggy/saturated and less receptive to absorption should totals
(between right now and Monday evening) approach 2." This could
lead to some isolated runoff issues and, at the very least,
should cause some rises on area waterways. But at this juncture,
given the decrease in signal for a heavier (>= 1") swath of
rain, even across the SE third of the ILN FA, there is just not
enough of a signal to warrant a bigger concern for larger-
scale/widespread flooding concerns.
Drier conditions evolve toward later Monday evening following
the FROPA, with slightly cooler/drier air filtering in for
Monday night.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Negatively tilted trough associated with an active 500H wave train
pattern will be moving through the Great Lakes and Ontario with its
associated surface feature dragging an occluded/ cold front through
the Ohio Valley. The coldest 850mb air remains well north of the
CWA, however, we'll feel some subtle cold air advection on the
backside of the system and overnight lows drop into the mid 30s.
Tuesday arrives dry with highs in the 40s as we are in between
waves, however this lull is brief.
THe next disturbance begins to dig in and rain will move back into
the region by Tuesday overnight into Wednesday. Ensemble (and
deterministic) guidance has been struggling with this system. The
ECMWF consistently pushing the highest QPF footprint to our south,
along the KY/TN border with the GFS holding onto a more northerly
solution. It should be noted that tonight's 00z GFS has trended a
tad farther south, so that lends a bit more confidence to the
southerly solution. Sensibly speaking, much of the area will receive
rainfall as we head into Wednesday morning and through the day on
Wednesday (temps in the 40s-50s), but highest confidence will be for
areas along the Ohio River. PoPs decrease Wednesday evening behind a
much stronger cold front and we may even see some wintry mix as
things wind down. Along this line of thought, this system carries
cold air much farther south, and our 850mb temps might end up around
-10 to -14 range with Wednesday night surface temps dropping to the
20s.
Again, do want to mention that with Sat/Sun overnight rain, Monday
rain, and this potential additional rain (highest along the Ohio
River?) we'll need to keep an eye on any hydro concerns.
Thursday arrives much cooler, with highs only reaching the low to
mid 30s with perhaps some lingering flurries in the residual
cyclonic flow, but signal isn't strong enough to include in the
forecast just yet.
Yet another wave moves through the northerly flow as a clipper-type
system looks to move into the region near the end of the work week.
We're a bit far out for details currently, but the active pattern
does seem to be relentless!
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Any lingering VFR CIGs will quickly transition to MVFR, and
eventually IFR, area-wide within the first few hours of the TAF
period. The steadier/heavier pockets of RA will lead to MVFR
VSBYs from time-to-time. IFR CIGs are expected to settle into
the region for the daytime through tonight, with some LIFR CIGs
possible as well, especially for nrn sites, for the second half
of the period.
Sfc winds will be generally out of the SE at 10-12kts through
18z. These winds will gradually subside by/after 00z to less
than 10kts, going more southerly by the end of the period.
The solid shield of RA is becoming more showery in nature, with
SCT to numerous SHRA lingering about through about 15z, becoming
isolated thereafter. Some patchy DZ may develop by 00z and
linger into early Monday, but confidence was not yet high enough
to include in the fcst at this juncture. IFR/LIFR CIGs, with
MVFR/IFR VSBYs, will be possible by 06z Monday amidst patchy
BR/DZ, especially for KDAY/KCMH/KLCK.
OUTLOOK...MVFR to IFR conditions are likely Monday into Monday
night, and again on Wednesday. Some MVFR CIGs may linger into
Wednesday night.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...CA
AVIATION...KC
Source: ILN issues Area Forecast Discussion (AFD) at Dec 15, 6:17 AM EST (https://mesonet.agron.iastate.edu/p.php?pid=202412151117-KILN-FXUS61-AFDILN)
---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!