772
FXUS63 KDVN 220522
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1222 AM CDT Sun Sep 22 2024

.KEY MESSAGES...

- Much cooler for Sunday and Monday with highs in the mid 60s
  to lower 70s, which is slightly below normal.

- Dry conditions are expected to prevail Tuesday through
  Thursday with high temperatures in the low to mid 70s.

&&

.UPDATE...
Issued at 1217 AM CDT Sun Sep 22 2024

A large area of rain, with some embedded thunder will continue
to move east over the south 1/2 of the area through early
Sunday. The movement is slow, but this should eventually make
it`s way through our entire area by 12Z. Rainfall amounts should
be very light north of a Cedar Rapids to Quad Cities to
Princeton Illinois line, and generally 0.25 to 1 inch farther
south.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 200 PM CDT Sat Sep 21 2024

An area of scattered showers and isolated storms has worked from
west to east through mostly the southern half of the outlook
area this morning into the early afternoon, leading to localized
downpours and gusty winds of 25-35 mph. This activity was likely
enhanced by a gravity wave propagating through the region as
shown on GOES visible satellite imagery and coincided with the
earlier uptick in areal coverage. The rain and widespread cloud
cover, especially south of I-80, has lowered temperatures to the
low/mid 70s across the south and southwest forecast area, while
locations to the north and east are in the upper 80s to near 90
degrees. For the remainder of this afternoon into this evening,
redevelopment of isolated showers and storms are possible but
with low coverage anticipated and much of the area likely to
stay dry. The prospects for severe weather remain low due to
waning instability heading into early tonight and only modest
deep layer shear around 25-30 kts per the 12Z HREF; SPC has
maintained the Marginal Risk (level 1 of 5) across the NW
portion of the forecast area.

A better chance for scattered showers/storms comes in late
tonight as convection initiating this afternoon over central
Iowa, and extending down into Kansas, slowly spreads ENE in
tandem with a surface cold front sagging in from the NW.
Additional rounds of rain with embedded thunder are expected
overnight into Sunday morning (highest chances southeast of
Dubuque to Iowa City ~80%). Rain amounts will vary quite a bit
across the region due to the spotty nature of the rain, but on
average anticipate 0.25 - 0.75 of an inch.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 200 PM CDT Sat Sep 21 2024

Sunday - Monday: An upper wave will move through the area, with
showers and isolated storms likely to linger through Sunday AM
before diminishing during the afternoon. An increasing northeast
wind and cold advection will keep temperatures steady in the
60s to low 70s both Sunday and Monday.

The upper trough will influence our area into Tuesday, with
some shower chances continuing in the southern CWA. As dry air
arrives, the overnight lows will drop to the upper 40s to lower
50s, making for chilly mornings more typical of early fall.
Slow moderation is forecast by late week, along with a slight
chance for rainfall. Late week forecast highs are in the 70s,
and lows in the 50s.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1217 AM CDT Sun Sep 22 2024

A cold front is now moving into eastern Iowa, with winds
shifting to northwest overnight. While VFR conditions are
currently found, an area of rain and embedded thunder over
southern Iowa (south of Interstate 80) will bring wet weather
overnight, especially at BRL. After 15Z Sunday, dry air will
return to lower levels, resulting in VFR weather again spreading
over the region, and mainly dry weather, though some spotty
rains may still be taking place.

&&

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

&&

$$

UPDATE...Ervin
SHORT TERM...Uttech
LONG TERM...Ervin
AVIATION...Ervin