612
FXUS63 KDVN 230547
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1247 AM CDT Thu May 23 2024

.KEY MESSAGES...

- Dry conditions for most today, with seasonable temperatures
  and comfortable humidity.

- Active weather returns by Friday and again early next week
  with increasing shower and thunderstorm chances. There is a
  Marginal Risk (level 1 of 5) for severe weather on Friday.

- The Cedar, Iowa, Skunk, and the Wapsi rivers are expected to
  rise with some sites going into flood in the next 3-4 days
  due to the recent 2-5 inch rainfall upstream.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 1205 PM CDT Wed May 22 2024

A beautiful early afternoon was unfolding across all of eastern
Iowa, northwest Illinois and far northeast Missouri; a nice
welcome after yesterday`s active weather. Skies featured mostly
sunny skies with temperatures as of noon ranging from the mid
60s to near 70. It was breezy as well with west to northwest
winds gusting around 20-30 MPH.

15z surface analysis showed a strong surface low just north of the
arrowhead of Minnesota, with high pressure in place across the
central Plains. The pressure gradient between the low and high was
rather tight and, along with deep boundary layer mixing, was
responsible for our gusty winds early this afternoon.

Over the next 24 hours, our weather will be influenced by the the
surface high as it slowly moves across the Plains into the mid-
Mississippi River Valley. Gusty winds will subside late this
afternoon and evening, becoming light & variable tonight into much
of Thursday. Skies will feature only a few clouds, allowing for more
of a diurnal swing to our temperatures compared to previous
days. Look for lows tonight in the low to mid 50s (some upper
40s possible in valleys and low-lying areas), with highs
Thursday recovering into the upper 70s to lower 80s ahead of
strengthening ridging aloft.

Will make note of a low chance of a shower or storm along and
north of the Hwy 30 corridor this afternoon with a lobe of CVA
moving through the area. However, this is low confidence given a
lack of moisture in place across the area.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 159 PM CDT Wed May 22 2024

Thursday night through Friday night...

Our next chance of showers and thunderstorms arrives early Friday
into the evening as a cold front moves across the Midwest. This will
be in tandem with a negatively tilted shortwave and increasing
diffluence aloft, increasing overall lift. Deep layer shear will be
high in the 35-50 kt range with CAPE climbing into the 1500-2500
J/kg range, increasing potential for organized convection. Storms
will also be capable of producing heavy rain as PWATs climb into the
1.25-1.50" range. Unfortunately, guidance is not in agreement of
timing of the front this far out, and confidence on pinpointing where
storms will fire is low. This is why there is a rather broad Level 1
(marginal) risk of severe thunderstorms for this period, which at
time includes all of the DVN CWA.

Saturday...

High pressure will provide a dry start to the holiday weekend. Look
for near normal highs in the low to mid 70s, and lows Saturday
morning in the upper 40s to mid 50s.

Saturday Night Through Memorial Day...

Active weather returns as we head into Memorial Day with several
shortwaves on track to move across the area. Ensembles including
the NBM paint higher chances (50-70%) Saturday night with good
agreement amongst deterministic guidance on more widespread
showers and storms. Exact details on storm hazards at this time
are low, though heavy rain is possible with a robust Gulf
connection and PWATs climbing above 1.50" across portions of the
area. Chances lower heading into early next week but remain
persistent through Tuesday (30-50%). Expect more details in the
coming days.

With the potential for precipitation, temperatures look to hold
around or just below normal for Memorial Day.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1247 AM CDT Thu May 23 2024

VFR conditions are expected throughout the TAF period. Southerly
winds will be in place as an area of high pressure settles
across the Ohio River valley. Some daytime cumulus clouds are
expected to develop late this morning through the afternoon, along
and north of Interstate 80, with ceilings around 5 to 6 kft.

&&

.HYDROLOGY...
Issued at 1030 PM CDT Wed May 22 2024

Watch/Warnings:

Issued a Flood Watch for Cedar River at Cedar Rapids for
potential to reach into the minor flood category in about 36 to
48 hours.

Canceled the flood warning for the English River at Kalona. It
crested near 14.2 feet earlier this afternoon and fell below
flood stage during the late afternoon. It will continue to
fall.

Most of the river forecasts are starting to be based on routed
flow. Some attenuation is still possible as the crest wave makes
its way through the river systems over the next two to seven
days. Because of this, confidence in some forecasts, especially
those forecast to reach flood stage or a respective flood stage
category beyond day 4, remain lower.

Continued the watches for the Wapsi at DeWitt and the Cedar at
Conesville which have over 2 days before reaching flood stage.
Warnings continue at Anamosa, Marengo, and Sigourney with no
category changes.

Overall, this evenings crest forecasts have come in slightly
slower and at or lower than prior forecast levels. Fore example,
the Skunk River at Sigourney is now a half foot lower with a
forecast crest a half foot over the Major stage.

Forecast adjustments and possible additional watches/warnings
will be made Thursday morning. Stay tuned.

&&

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

&&

$$

SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Schultz
HYDROLOGY...14