167
FXUS63 KDVN 041055
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
555 AM CDT Sat May 4 2024

.KEY MESSAGES...

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

- The Storm Prediction Center has a Marginal Risk (level 1 of 5)
  for severe storms on today for portions of the area.

- A potent dynamic system arriving Monday night to Tuesday could
  bring a more significant severe threat.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 225 AM CDT Sat May 4 2024

A large MCS is poised to enter western Iowa early this morning,
and is rapidly moving east/northeast. This has been severe in
Nebraska, but will be quickly moving out of the marginally
unstable air and should become predominantly stratiform rain in
the next 4 hours prior to sunrise as it moves through Iowa and
southern Minnesota. For us, skies will become high overcast
before sunrise, and winds will continue to increase from the
south/southeast. Some showers may near our northwest prior to
12Z, but this looks to hold off until then, and move into our
northwestern 1/3 of the CWA before 10 AM. While in a dissipating
stage, some thunder is possible, and will keep it`s mention in
grids.

During the late morning to early afternoon, coverage of rain in
Iowa will wane, allowing some decent heating to occur in the
east 1/2 of the CWA. the NBM supports highs in the upper 70s to
around 80 today along and east of the Mississippi River, with
dew point temperatures rising to the low 60s just ahead of the
front. Modest CAPE of 500 to 1200 is forecast by most CAMs this
afternoon in our east 1/2. The surface cold front should
reinitiate convection near the Mississippi River. NBM pops came
in today ~90% with the fropa, but with about 1/2 of the CAMs
failing to convect today, I`m inclined to limit pops to 80% in
the narrow fropa timing this afternoon. Anyhow, SPC is
maintaining the Marginal Lvl 1 risk for mainly wind and hail.
This is a low risk, but will be highest with the storms that
form along the front this afternoon.

By early evening, storms will have exited the area to the east,
with rapid clearing and a chilly night in the upper 30s to mid
40s in store.

Sunday, with cool air in place, a pleasant spring
day is forecast, with some diurnal cumulus dotting the sky as
well. Highs are forecast to reach the upper 60s to lower 70s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 225 AM CDT Sat May 4 2024

A broad, energetic pattern is set to begin spreading WAA rain
and thunder into the area as soon as Monday, with widespread
showers and thunderstorms expected Monday night into Tuesday.

This Monday night into Tuesday period continues to be shown as a
large/synoptic, strongly forced system, and there`s been a
consistent signal for a very strong jet streak within the
Midwest. Those broad scale factors continue to give an
indication that this may be a widespread severe weather
producer, and our CWA may be included in that. We will begin
messaging this chance today in the HWO.

A warm and breezy pattern is in store on the east side of this
broad potent trof next week. Highs in the 70s to lower 80s are
expected through Wednesday. Following that, the upper trof is
set to deepen, and place the warm air well south of the upper
Midwest, resulting a cooler, cloudier forecast in the 60s to
lower 70s to end the week. This could bring additional showers
and possibly thunder to the region as well, given the cold air
aloft and time of year over moist soil. The QPF in this period
should not be overly heavy, given no connection to the Gulf of
Mexico, but spotty rains over 0.50 appear possible in the
frequent shower chances to end the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 551 AM CDT Sat May 4 2024

An approaching area of showers and thunderstorms will reach eastern
Iowa TAF sites of CID and DBQ between 13 and 15Z this morning.
Visibilities in thunder may drop to 3-5 miles in heavy rain, but
overall the intensity of this cluster of storms is expected to
weaken. Some MVFR cigs are possible as the rain decays in
northeast Iowa this morning. There will be two periods of
rain/thunder potential, one in the morning west, and the other
in the mid to late afternoon along and east of the Mississippi
River. Some of the afternoon storms could offer a strong wind
gust, and brief IFR conditions.

Tonight, clearing is expected with northwest winds blowing 12 to
20 kts.

&&

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

&&

$$

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