264
FXUS63 KDVN 121038
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
538 AM CDT Sun May 12 2024

.KEY MESSAGES...

- Today will be the warmest day of the next 7 with highs in the
  80s. Scattered showers and isolated storms are possible late
  this afternoon into tonight.

- Periods of showers and thunderstorms are likely on Monday with
  the heaviest rainfall amounts anticipated south of I-80.

- Zonal flow aloft across the Western to Central U.S. will
  result in active weather continuing through the next week.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 245 AM CDT Sun May 12 2024

Today

Warm and breezy today as low pressure tracks across Lake
Superior. Steady SW winds, gusting near 25 mph, will advect much
warmer air into the region with highs reaching the low to mid
80s. Humidity will remain comfortable with dewpoints reaching
the upper 40s to lower 50s, which will limit afternoon/evening
instability. We are still looking at chances for scattered
showers and isolated storms late afternoon/evening into tonight.
Coverage through the afternoon and evening may remain
relatively low (20-30%) due to lack of a focused trigger.

HREF has surface-based CAPE peaking around 1000 J/kg with deep
layer shear under 30 kts. Therefore do not anticipate severe
weather, but a few of the stronger cells could produce localized
wind gusts over 40 mph due to a dry sub-cloud layer shown on
forecast soundings. A weak cold front dropping in from the NW
tonight may lead to slightly higher coverage of rain (30-50%),
mainly across northwest and western counties.


Monday

An upper low on the northern periphery of the subtropical
jet is forecast to slowly track from the Southern Rockies to
the Lower to Mid Mississippi Valley early in the week. This will
keep the local area on the cooler side of the surface low.
However, a slower arrival of the system should allow temps to
reach into the 70s across the east, with cooler 60s in the
west. Occasional showers with isolated storms are expected from
Monday morning into Monday night. Dewpoints will continue to
trend upward from the weekend, reaching the lower 60s by Monday
afternoon which will contribute to 1000-1500 J/kg of SBCAPE. So
there is a potential for thunderstorms, especially in areas that
can squeeze out some breaks in the clouds. Deep layer shear is
weak, limiting the severe risk and SPC has kept the area in a
general thunder outlook.

NBM chances for measurable rain range from near 60% in the far
NW corner of the outlook area to ~90% south of I-80. The 24 hour
probability for 0.50" or more of rain has remained consistent,
peaking between 50-70% south of I-80 and dropping down to
20-30% near Highway 20.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 245 AM CDT Sun May 12 2024

Tuesday: Shower chances will continue at least through the
morning hours as the vertically stacked system tracks across
central and southern Illinois. Otherwise, we`ll have breezy NE
winds and seasonable temps in the upper 60s to low 70s.

Wednesday - Saturday: Ridging aloft and surface high pressure
is forecast to build in later Tuesday into Wednesday, leading to
a break in the wet weather. The next system to impact the
region arrives by late Wednesday into Thursday, bringing another
round of widespread rain to the outlook area. Once again there
is uncertainty on how quickly this system pushes to our east.
The NBM has a chance for rain (30-40%) continuing through
Friday which is reasonable given the model discrepancies.
Forecast temperatures late in the week are near to slightly
above normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 530 AM CDT Sun May 12 2024

VFR is expected today with SW winds increasing by mid/late
morning. There is a chance for scattered showers and isolated
thunderstorms this evening into tonight. Due to low confidence
on areal coverage, mentioned showers in PROB30 groups for CID
and DBQ late in the period.

&&

.HYDROLOGY...
Issued at 833 PM CDT Sat May 11 2024

Latest forecast this evening for the Wapsipinicon River near De
Witt has a slower rise by several tenths of a foot. However,
minor flooding is still expected but a little later now on
Tuesday May 14th. Given how the initial crest was lower and
attenuation of routed flow confidence is dropping, confidence is
low in just how high above flood stage the river will get. Will
continue the Flood Warning with this issuance.

In addition, the forecasts on the Cedar and Iowa Rivers have
lowered at Conesville and Marengo. Both sites now just touch
flood stage on Wednesday. Will continue the flood watches for
now, but if trends continue in the coming days the flood watches
may need to be cancelled.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Uttech
AVIATION...Uttech
HYDROLOGY...Gross