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000
FXUS63 KDVN 231105
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
605 AM CDT Tue Apr 23 2024

...12Z Aviation Update...

.KEY MESSAGES...

- Precipitation chances continue through today, along with rounds
  of blustery conditions.

- There is a low potential for a strong/severe storm this afternoon
  mainly east of the MS RVR in IL.

- Colder air returns midweek with frost possible Wednesday night in
  northern IL.

- Turning warmer and active by the end of the week through the
  upcoming weekend, with potential for rounds of showers and
  storms. Severe weather and heavy rain are possible.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 330 AM CDT Tue Apr 23 2024

Today...Short wave seen now on water vapor imagery acrs the northern
half on MN into the Dakotas, will look to shear acrs the
southwestern GRT LKS by this evening, with an associated sfc
reflection front sweeping acrs the CWA from the northwest and
crossing the MS RVR around 20-21z or so. This system is currently
inducing elevated H85-H7 MB F-gen forced band of showers and some
thunder acrs NE into northwestern MO ATTM, and this activity will
continue to develop some and move acrs the southern third or more of
the DVN CWA from dawn to midday, with dry airmass saturating enough
to produce a few swaths of a quarter inch to half inch of rainfall
acrs northeastern MO into west central IL.

Attention then turns to the front itself with possible narrow ribbon
of upper 40 to near 50 sfc DPTs pooling along it as it moves acrs
the area. With a pool of steep low to mid level lapse rates of 7+
C/km along the frontal forcing(Much steeper upstream post-frontally
over 9 C/km!) and shallow storm effective shear levels of 25-35 KTs
are in the low-topped supercell development mode. SBCAPEs may range
200-400 J/kg with the forcing/shear in the eastern CWA/IL side.
Thus a low chance for a strong to severe storm cell to possible make
it into the eastern fcst area this afternoon. Severe size hail and
gusty winds the main threats, but an isolated tornado not out of the
question. With the dry airmass in place and then getting re-enforced
post-frontally from the northwest, there is the possibility that
hardly anything develops locally as well.

Post-frontal fcst soundings show developing deep mixing up over H8
MB and inverted-V soundings developing. Thus with some cold air
advection(CAA) lag, this deep mixing with some sky clear out will
help zoom afternoon temps to projected high values in the mid 60s to
near 70 behind the cold front! Gradient NW wind gusts look to be at
least 35 MPH. Isolated to wdly sctrd showers and possible
thunderstorms will pop post-frontally acrs southern MN into WI, and
then try to drift southward toward the local area into the evening.
But most of these should decay diurnally and with post-frontal
processes and drying before they make it down much acrs the local
area. If they can hold together, they will be able to produce
enhanced wind gusts over 40 MPH utilizing the inverted-V soundings.

Tonight...Clearing with post-frontal CAA dragging temps down into
the low 40s south, to the mid 30s north. With north winds maintaining
5-10 KTs into Wed morning, will not mention frost in the north.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 330 AM CDT Tue Apr 23 2024

Wednesday and Thursday...Backdoor/western GRT LKS sfc ridge for a
sunny but cooler Wed with highs in the mid 50s northeast to low 60s
west. Wed night with high pressure continuing acrs the GRT LKS and
upper ridging amplifying acrs the plains, another clear cool night
with lows in the 30s to low 40s. The coldest temps in the low to mid
30s with longest light wind residency may foster some frost, and the
most likely areas for this will be acrs northwest IL. Warming and
dry Thu in ongoing/increasing southeasterly BL return flow regime,
highs back in the 60s. Developing/organizing high amplitude cyclonic
southwesterlies to lee of southwestern plains strong upper trof may
usher acrs the first salvo of an active weekend by late Thu night
into early Friday morning in the form of elevated WAA driven
shower/storm clusters into the southwestern CWA.

Friday...AI progs and recent ensemble synoptic scale forcing zones
suggest the prime severe set up this day will  look to take place
more off to the south and southwest of the DVN CWA acrs the
southeastern plains and MO/AR. But secondary strong to severe storms
with heavy rainfall still look on target for the local area Friday
and Friday night. Will maintain and build upon ongoing POPs and
product messaging.

Saturday through Monday...Again assessing the ensembles with
moisture feed and longer range projected thermodynamic/kinematic
overlays, Saturday may be a bit of a reprieve day until things come
together for a stormy Sunday and ominous set-up with classic looking
synoptic scale features for a severe weather outbreak somewhere acrs
the mid CONUS.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 558 AM CDT Tue Apr 23 2024

VFR level clouds continue to move across the area with isolated
light showers and a few storms southeast of the Quad
Cities. This while a more organized band of showers and a few
embedded thunderstorms move along south of I80 through late
morning. This shower area will affect mainly the BRL site with
MVFR CIGs and rain reduced VSBYs at times this morning,
possibly clipping the MLI site with light rain but more likely
staying just off to the south or maintaining at VFR levels.
Clearing with a sfc wind switch from southwesterly this morning
to the northwest this afternoon. The northwest sfc winds may
gust up to 30+ KTs into early evening behind the FROPA before
decreasing as the evening progresses. Will bank on isolated to
sctrd showers/storms along the frontal passage to stay mainly
east of the TAF sites Tue afternoon, but they may get close to
MLI.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...12
LONG TERM...12
AVIATION...12