683
FXUS63 KDVN 111030
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
530 AM CDT Sat May 11 2024

.KEY MESSAGES...

- Nice weather to start the weekend with dry conditions and
  temperatures in the 70s today!

- Warmest day in the next week will be Sunday with highs in the
  80s; isolated to scattered storms are possible late Sunday
  afternoon into Sunday night.

- The pattern will remain active next week as zonal flow aloft
  guides a series of shortwaves through the Midwest.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 318 AM CDT Sat May 11 2024

Today: Seasonably warm with plenty of sunshine and highs in the
low/mid 70s. NW winds will increase late morning into the
afternoon, gusting 20-30 mph.

Sunday: Low pressure passing near Lake Superior will pull warm
and more moist air northward into the local area with forecast
highs into the low to mid 80s. With dewpoints only in the 50s,
humidity will remain comfortable and instability will peak
around 1000 J/kg (per HREF SBCAPE). Deep layer shear is also on
the low side at 20-30 kts, which will limit storm organization.
Most CAMs develop isolated convection during the late afternoon
and evening, with coverage increasing into Sunday night (30-50%).
A dry sub-cloud layer shown on forecast soundings Sunday
afternoon and evening would be supportive of gusty winds with
the strongest cells, potentially over 40 mph.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 318 AM CDT Sat May 11 2024

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 and more
stable side of the surface low. Rain is likely to spread in
from SW to NE during the morning and afternoon. NBM chances for
measurable rain range from near 50% 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 reaches 50-70% south of I-80 and drops
down to 20% near Highway 20. The NBM may still be running too
warm for max temps due to the likelihood for widespread clouds
and rain; these may need to be lowered by several degrees in
later updates.

Tuesday - Friday: There remains uncertainty with how fast the
rain moves out on Tuesday. The ECMWF lingers the rain through
the morning across the south half of the outlook area, while
the GFS/CMC shift it to the SE more quickly. Our current
forecast is leaning towards the latter scenario. Then it looks
like we will get a break from the rain later Tuesday through
Wednesday before the next shortwave trough and associated cold
front arrive by Wednesday night into Thursday. Late week temps
are forecast to be slightly above normal in the low/mid 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 523 AM CDT Sat May 11 2024

High pressure will lead to prevailing VFR through tonight.
NW winds will increase during the mid to late morning and gust
between 20-25 kts through the afternoon. No precipitation is
expected through the period.

&&

.HYDROLOGY...
Issued at 955 PM CDT Fri May 10 2024

The Flood Warning continues for the Wapsipinicon River near De
Witt. The initial crest has come in considerably lower and
below flood stage, so the river is now expected to go into
Minor flooding on the evening of Monday, May 13th when the
second crest due to routed flow occurs. Given how the initial
crest was lower and attenuation of routed flow confidence is
dropping a bit on the river reaching flood stage.

The overall situation with the Cedar and Iowa Rivers is more
uncertain. Flood watches remain in effect for Marengo on the
Iowa river, and the Cedar River near Conesville. The Iowa
River at Marengo is forecast to go into Minor flooding Sunday
evening May 12, while the Cedar River near Conesville is
forecast to go into Minor flooding early Tuesday morning, May
14.

Rainfall over the next 72 hours and where it occurs will be the
deciding factor as to whether or not the Cedar and Iowa Rivers
will reach flood stage near Conesville and at Marengo
respectively. If the rainfall is lighter than expected then
river forecasts may be lowered. However, if rainfall is heavier
than expected then river forecasts may be raised.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Uttech
AVIATION...Uttech
HYDROLOGY...McClure