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145
FXUS63 KDVN 030525
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1225 AM CDT Fri May 3 2024

.KEY MESSAGES...

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-  Upper level pattern remains active, with periodic chances for
   showers and storms through next week.
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&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 302 PM CDT Thu May 2 2024

Early afternoon surface analysis showed a weak area low
pressure centered across west central Iowa, wit ha warm front
nearly right along the Interstate 80 corridor and a cold front
across southwest Iowa to eastern Kansas. Rain showers and storms
from WAA processes have wained significantly in the last few
hours, though some remained mainly in southeast Iowa nearer to
some stronger forcing aloft. Elsewhere, skies featured a mix of
clouds and sun to dense overcast with temperatures ranging from
the low 60s (east central Iowa) to upper 70s (northwest
Illinois).

Look for the surface low, warm front and cold front to progress
northeast across the region over the next 12-18 hours. A passing
shortwave currently over southeast Kansas and southwest Missouri
will interact with this system and increase lift across the region,
leading to renewed shower and thunderstorm development this
afternoon and evening. This is favored ahead of the front mainly
along and east of the Mississippi River where temperatures are
warmer and higher instability exists. Latest CAMs favor instability
in this area climbing to around 1000-2000 J/kg thanks to steep low-
level lapse rates, along with sufficient deep layer shear around 25-
35 kts for organization. Damaging winds and large hail would be the
primary threats with storms, with a tornado threat possible if any
storms can latch on to the warm front or remnant outflow boundaries.
Latest

In addition to the severe threat, PWATs across the region ahead of
the cold front remain high around 1.25-1.50". This will ensure
thunderstorms capable of producing torrential rains in a short
amount of time, especially over areas that seeing training storms.
The primary areas of concern are urban areas and locations in
southeast Iowa (a Flood Watch is in effect here due to the heavy
rains from this morning), west central Illinois and northeast
Missouri thanks to their heavy rains from the past week. Elsewhere,
soil conditions remain near normal to anomalously dry per CPC
analysis, which favors the ground being able to soak up a majority
of the rainfall.

Once the cold front front passes through the area tonight,
conditions will improve for the end of the work week with high
pressure quickly passing across the area. Areas of mist/fog may be
possible Friday morning mainly in east central Iowa where leftover
moisture from this morning`s rains persist. Elsewhere, skies will be
mostly sunny with continued above normal highs in the 70s
expected.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 302 PM CDT Thu May 2 2024

The weather will remain active going into early next week as a
trough over the eastern Rockies and strong closed low just north
of Montana sends several disturbances into the area. Each day
through next Thursday will feature at least a slight chance of
precipitation.

The first definite chance of precip comes Saturday morning and
afternoon as a complex of showers and storms moves across the area
with a weak front and shortwave aloft. At this time the primary
threat looks to be lightning and heavy rain with PWATs climbing back
to around 1.50". Severe chances are low with increasing cloud cover
hampering instability and unfavorable lapse rates.

Conditions will dry out to close the weekend with precipitation
chances returning for Tuesday with another round of AM showers and
storms expected. There is quite a bit of uncertainty with this
system as guidance varies on the frontal timing and availible
moisture, so look for additional changes to this period in subsequent
forecast packages.

Temperatures look to remain above normal with highs in the 70s/near
80 and lows in the 50s/60s. As the previous AFD mentioned, outside
of the rain chances it will be a nice week!

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
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Issued at 1220 AM CDT Fri May 3 2024

A cold front has now moved through all TAF sites and is slowly
making its way through Illinois as of 5Z. A band of light rain
showers is still moving east slowly through far eastern Iowa and
northwest Illinois. This is light, and mostly associated with
visibility of 6SM or better, and variable cigs between 600 ft
and 2500 ft. This rain and cigs will end by 07z at sites along
the Mississippi River, and is already done at CID. Clearing is
expected between 08z west and 11Z east, and with that, some
ground fog formation is possible, especially in Iowa where
heavier rain totals fell in the past 24 hours. This fog would
burn off by mid morning if it forms, with prevailing VFR
weather in light winds the remainder of the day, which will
trend toward east/southeast by mid morning.
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&&

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

$$

SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Ervin