Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 182320
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
620 PM CDT Mon Mar 18 2024

.KEY MESSAGES...

-  Warmer temperatures, dry air and windy conditions are expected
  Tuesday and will produce another enhanced fire danger to the area.

- Pattern becomes active through the end of the week as passing
  system`s bring precipitation chances to the area. We continue
  to see the freezing line near or in the area as well as cold
  air aloft suggesting that we could have some spring snow
  chances.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 239 PM CDT Mon Mar 18 2024

Tonight...Large sfc ridge sliding southward acrs the
central/southern plains and MO RVR Valley, while elongated vort
complex almost sheared out and channeled was noticed acrs northern
Alberta. This upper vort energy will clipper it`s way down acrs the
GRT LKS on Tue, shunting an associated sfc front through the area by
early afternoon. As the sfc ridge moves off and this upper wave
system digs down acrs the upper MS RVR Valley, anti-cyclonic LLVL
flow will go cyclonic southwesterly and really tightens. This with
west-northwest low level jet(LLJ) flow increasing to 35-45+ KTs will
make for high low to mid level wind fields acrs the area by late
tonight. Enough pre-frontal mixing indicated on BUFKIT soundings to
drive sfc wind momentum with gusts 35 to 40 MPH, especially acrs the
southwest half of the DVN CWA. With the cellular and patchy CU
eroding for a mainly clear night and ongoing low sfc DPTs in place,
temps should drop off after dark down in the 20s. Then expect a late
night non-diurnal temp trend before dawn as the southwesterly pre-
frontal winds increase and start to gust.

Tuesday...Looks like a dry FROPA by late morning to midday sweeping
acrs the local area. A temporary sfc wind dip along this process,
then post-frontal winds will veer to the northwest during the
afternoon with gusts up to 35 MPH. This Tue afternoon period with
sfc RH`s dropping well down in the 30s and mild mixed up sfc temps
in the 50s and even some lower 60s in the south, will be the
enhanced fire danger window with Grassland Fire Danger Index(GFDI)
readings in the very high range. While not quite high enough for Red
Flag Warning headlines, still enough to cover and alert the fire
danger in several other products.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 239 PM CDT Mon Mar 18 2024

Wednesday...A cool day with mid to upper MS RVR Valley sfc ridging
and incoming pressure gradient inducing NNW sfc winds of 10-20 MPH
until they decrease by late afternoon. LLVL cool baroclinicity aligns
parallel under NW-to-SE steering flow aloft and will look to
tighten from the northwest high plains to the OH RVR Valley. With
the potential for a weak upper wave or trof to ripple down along
this thermal ribbon and the local area looking to be on the cool
side, we may some periods of flurries or light snow at times getting
milked out of any stratocu deck streaming acrs the area especially
Wed night. May be initially virga with the low to mid level dry air
in place, bu then a few flakes may be realized at the sfc with the
ongoing elevated F-gen/isentropic lift. Wed highs in the upper 30s
to low 40s.

Thursday and Friday...Latest run ensembles and blends still suggest
a bit more organized and vigorous short wave/clipper type system to
propagate along the ongoing baroclinic storm track, with some
decent sfc reflection low pressure development rolling in near or
acrs the local area late Thu night into Friday morning. This feature
to bring rain,rain-snow mix, and probably all wet snow looking at
the vertical thermal profiles by Thu night. Before hand,
southeasterly return flow ahead of the clipper should bring about a
bit of a sfc temp warm up with highs in the mid to upper 40s acrs
the southwest half of the DVN CWA. Current indications suggest there
will be cool enough vertical profiles north of I-80 trending a rain-
snow mix into all snow as the night progresses into, with some light
snow acumms possible especially on elevated surfaces. Several model
blends and ensembles show a 75th percentile of 1-3 inches of snow
along the Hwy 20 corridor by Friday morning. There may also be a
wintry mix transition zone off to the south of the snow before we
get more into a regular rain supporting airmass south of I-80. Still
plenty of details to be worked out. Would think Friday a mostly
cloudy post-frontal day and some worry the loaded blend of temps may
be a bit optimistic on the mild side.

Saturday and Sunday...Current ensemble trends suggest Saturday to be
a lull day in between systems, while some type of longer wave
troffiness and rounding upper jet energy organize upstream acrs the
western CONUS. As there are long range signs of a mild moist
conveyor streaming up off the western Gulf to lee of the trof
complex, precip chances may really ramp up from late Sat night or
Sunday into early next week. But with the spread between solutions
and ensembles, very low confidence in QPF amounts, placements and
types at this juncture in the game. The one consistent signal is
that there may be a significant storm system traversing somewhere
acrs the mid CONUS early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 614 PM CDT Mon Mar 18 2024

Wind will dominate an otherwise VFR TAF period through Tuesday.
Winds tonight will be west to northwest at 10 to 20 kts early
this evening, but will decrease under 10 kts west by 01Z through
midnight. An approaching clipper system passing to our north
will bring increasing southwest winds after midnight, with
surface winds southwest at 14 to 22kts by 09z. In this period,
winds aloft will be much higher, and LLWS is forecast at 2000 ft
AGL, where winds are west to southwest at 40-45 kts. This LLWS
should continue though 14Z Tuesday, before the LLWS decays and
northwest winds at the surface shift to northwest at 12 to 20
kts.

&&

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

&&

$$

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


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