270
FXUS63 KDVN 041850
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
150 PM 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 Slight Risk (level 2 of 5)
  for severe thunderstorms across much of northwest Illinois for
  this afternoon and early evening, and a Marginal Risk (level
  1 of 5) to the west. The primary threats are strong wind gusts
  and hail.

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

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 145 PM CDT Sat May 4 2024

This Afternoon and Evening

A cold front currently located from near Decorah, Iowa to
Kirksville, MO will steadily progress eastward through the
outlook area this afternoon and evening, serving as the focus
for scattered storm development. Low-level moisture advection
via southerly flow has pushed dewpoints into the low/mid 60s
ahead of the front, and locations along and east of the
Mississippi River have had periods of filtered sun with temps
warming into the mid/upper 70s.

Trends with latest CAMs has been for a little lower coverage of
storms this afternoon and early evening, so have lowered rain
chances a bit. The best chances (40-70%) for storms are
expected in counties along/east of the Mississippi River between
3 - 6 PM. Overall the environmental setup (500-1500 J/kg MLCAPE
and ~30 kts deep layer shear) looks supportive of a few strong
to severe storms with the weaker shear as a limiting factor.
The strongest cells that pop up could produce wind gusts of 50
to 60 mph and hail up to quarter size, with this likely to
occur on an isolated basis.

Tonight and Sunday

A drier and much cooler post-frontal air mass ushers in tonight
with forecast lows in the upper 30s NW to upper 40s east/southeast.
Sunday will be very nice with highs in the upper 60s to low 70s
and fairly light winds through the day.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 145 PM 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. SPC has a Day 4
Slight Risk for severe weather encompassing the entire outlook
area. Latest CSU ML probabilities for severe weather also
highlight the local forecast area, with the max values to our
southeast over central to southern Illinois into Indiana.

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 /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1200 PM CDT Sat May 4 2024

A cold front will move through eastern Iowa and northwest
Illinois this afternoon and evening, leading to periods of MVFR
ceilings. The morning round of showers and storms has quickly
diminished, but redevelopment of scattered showers/storms is
anticipated by mid afternoon. The coverage of storms will likely
remain scattered and the higher chances for thunder are at
MLI/BRL, which was mentioned in a TEMPO. A return to VFR is
anticipated this evening/early tonight with breezy NW winds
through 6 PM - 9 PM before subsiding.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Ervin/Uttech
AVIATION...Uttech