Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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782
FXUS63 KDVN 041128
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
528 AM CST Mon Nov 4 2024

.KEY MESSAGES...

- Another round of moderate to heavy rainfall is expected
  tonight with the highest amounts along and east of the
  Mississippi River (1-2"+).

- There is a Marginal Risk for a few severe storms tonight to
  the south of I-80.

- Drier and more seasonable weather is forecast by the middle
  to end of the week with highs in the 50s.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 330 AM CST Mon Nov 4 2024

Early AM: The well advertised active pattern will continue into
Tuesday with two more rounds of rain expected through this
period. The first of which is currently impacting approximately
the southeast half of the outlook area from near the Quad Cities
and points to the east and south. The deeper convection with
this early morning round will remain south of the area across
central/northern Missouri into central Illinois. With PWATs
between 1.20-1.50" still anticipate efficient rainfall on the
northern edge of this batch of rain that has exhibited some
pockets of heavier rain associated with convective elements
embedded within the larger stratiform shield. However, the
quick NE movement should hold amounts to 0.25-0.50" or less even
in the eastern counties. Central to western sections will see
little to no additional rainfall through the morning hours.

We then look to catch a break in the widespread rain for much
of the day as the area is void of a surface front or upper wave
to initiate additional showers and storms. It will be very mild
for this time of year with highs in the mid 60s to near 70
degrees!

The deep upper trough across the Southwest U.S. is forecast to
edge into the southern Plains later today, which will coincide
with peak daytime heating and lead to a severe thunderstorm
outbreak across portions of Oklahoma, Missouri, and Arkansas.
This cluster of deep convection will quickly grow upscale with a
reinvigorated low to mid-level jet (50-60+ kts at 850mb)
directing the associated heavy stratiform portion of the cluster
northward into portions of eastern Iowa and northwest Illinois
by tonight. As mentioned for the past several days, the
atmosphere will become anomalously moist with PWATs and IVT
values peaking near the NAEFS and ECMWF ensemble 99th
percentile to climatological max.

Additional Heavy Rain Tonight: The enhanced IVT will act as a
fire hose of moisture, advecting the narrow corridor of heavy
rain and embedded storms up into portions of the outlook area
tonight, most likely between 6 PM to midnight. Model ensemble
consensus (NBM and HREF) is for the heaviest rain (2"+) to fall
east and southeast of the Quad Cities, which aligns with the
highest forecast IVT values. Fortunately, this part of the
forecast area missed out on the heaviest rain with the initial
round Saturday night into Sunday AM, making the soil conditions
more receptive to absorbing this final round of significant
moisture; the main concerns in the hardest hit locations are
ponding of water in low-lying and poor drainage areas, along
with quick rises on area creeks, streams, and tributary rivers.

Thunderstorm Potential: A warm and very humid air mass
(dewpoints in the lower 60s) will advect into the region from
the south, out ahead of the approaching line of convection set
to move into the southern forecast area by early tonight. SPC
has maintained a Marginal Risk for severe storms to the south of
I-80 with the primary threat damaging wind gusts and a low
potential for a brief tornado. It will be a typical out of
season high-shear low-CAPE environmental setup. With the
convection coming in at night, surface-based CAPE will be
meager. However, the highly sheared environment may compensate
for the weak instability, providing a mechanism for QLCS
organization and potential for localized strong wind gusts and
possibly a brief spin up tornado.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 330 AM CST Mon Nov 4 2024

The surface low will continue to lift northeastward during the day
Tuesday, so some lingering showers and perhaps an isolated
thunderstorm will be possible during the morning hours. As the
low deepens to the north across Wisconsin, we can expect gusty
SW winds to develop, reaching 30-35+ mph during the afternoon.
An area of high pressure will take control over the region
Wednesday through Friday. The next decent chance for rain comes
in Friday night into Saturday (40-60%). High temperatures
Wednesday through Saturday will be in the upper 50s to near 60,
with lows in 30s/40s.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 515 AM CST Mon Nov 4 2024

A humid air mass will lead to periods of MVFR/IFR ceilings
early this morning as the rain gradually diminishes; there
could be a brief window of VFR/MVFR ceilings for the afternoon
with little precip across the region. Then heading into
tonight, another round of widespread rain with embedded
thunderstorms will move into eastern Iowa and northwest
Illinois. The rain may become heavy at times, especially at BRL
and MLI, and be accompanied by gusty winds and reduced
visibilities to 1-3 SM. Low ceilings are expected through the
overnight with IFR likely at CID and DBQ.

&&

.CLIMATE...
Issued at 225 PM CDT Sat Nov 2 2024

Record Daily Precipitation Amounts:

November 4:
KBRL: 1.61/1935
KDBQ: 1.61/2022
KMLI: 1.51/2022

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Schultz/Uttech
AVIATION...Uttech
CLIMATE...Schultz