516
FXUS63 KDVN 022003
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
303 PM CDT Thu May 2 2024

.KEY MESSAGES...

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

-  There is the risk for heavy rain and a Marginal Risk for
   Severe Weather today and into this evening.

&&

.SHORT TERM /THROUGH FRIDAY/...
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 /FRIDAY 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 /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1233 PM CDT Thu May 2 2024

An active TAF period is in store for the area thanks to a nearby
cold front and an approaching disturbance aloft. Rain showers
currently in the KCID/KDBQ vicinities will give way to renewed
shower and storm development areawide in the next 2-4 hours,
with impacts expected mainly expected at KMLI/KBRL (TEMPO groups
have been included in this forecast). Conditions will
deteriorate to MVFR, with heavier showers and storms bringing
brief drops to IFR. There is a low risk that these storms will
be severe, with the primary risks being variable wind gusts
around 40-45 kts and large hail. These storms will move east by
03.00z, with leftover MVFR rain showers and ceilings along the
front persisting through the evening hours. Conditions will
improve to VFR after 03.06z, with gusty winds decreasing and
veering to the north.

For Friday morning, latest CAMs are hinting at fog development
at KCID/KDBQ thanks to leftover moisture from rains from this
morning. However, this is low confidence, so have only
introduced a brief drop to MVFR visibilities. Look for more
detail in this from later shifts.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Flood Watch until midnight CDT tonight for IAZ076-077-087-088-
     098.
IL...None.
MO...None.

&&

$$

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