602
FXUS63 KDVN 041955
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
255 PM CDT Thu Jul 4 2024

.KEY MESSAGES...

- There is a marginal risk (level 1 out of 5) of severe storms
  along and north of Interstate 80. There is a slight risk
  (level 2 out of 5) for Buchanan County.

- Wrap around rain showers are possible through the day on
  Friday.

- Several rounds of showers and storms are possible in or near
  the area Saturday night through Monday.

- Moderate to Major River Flooding continues, with further
  changes to river forecasts expected as we transition from
  predicted rainfall to observed rainfall over the next 36 hrs.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 255 PM CDT Thu Jul 4 2024

At 1 PM, scattered showers are moving eastward across far
eastern Iowa into northwest Illinois. These showers are
producing light rainfall at times. Temperatures range from 75
degrees at KAWG and KCID to 80 degrees at KMQB. Dewpoints across
the area are in the upper 60s to lower 70s.

Scattered showers are forecast to exit to the east by mid afternoon
as shortwave exits into eastern Illinois with some clear skies
behind the showers resulting in a few hours of warming across the
area. Convective Allowing Models (CAMs) show CAPE
increasing to 500 to 1500 J/KG into this evening ahead of a
shortwave that will move across the area after 00 UTC. Models show
sufficient shear across the area for severe thunderstorms with 45 to
55 knots across the area this evening. The marginal risk (level 1
out of 5) has been shrunk to along and north of Interstate 80 today.
There is a slight risk (level 2 out of 5) for Buchanan County. CAMS
show storms developing in north central Iowa by late
afternoon ahead of a cold front and moving southeastward across our
eastern Iowa counties after 7 PM and then exiting our northwest
Illinois counties after 1 AM. There is still some uncertainty in the
southward extent of showers and storms tonight so for now the best
chances are along and north of Interstate 80. Think that the main
threats are hail and damaging wind gusts. Models show the cold front
exiting the area prior to 12 UTC on Friday. Low temperatures tonight
are in the mid 60s across the area.

The 500 mb trough and closed low are forecast to slowly move
eastward through the day on Friday from northeast Iowa into Lake
Michigan by 00 UTC Saturday. This will result in 20 percent chance
of wrap around rain showers through the day on Friday as cooler air
aloft and lift allow showers to grow quickly.  High temperatures on
Friday are forecast to be in the mid to upper 70s. Gusty west winds
are forecast to develop Friday morning with speeds of 10 to 15 MPH
and gusts up to 25 MPH.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 255 PM CDT Thu Jul 4 2024

Dry conditions are expected late Friday night through Saturday,
as the upper low moves east of the area and high pressure
builds in behind it.

Saturday night through Monday, the high will then exit east
with a trough setting up in the plains. Several waves will move
across the region during this period. The first wave with
better precip chances clips our NW half of the CWA Saturday
night into Sunday. The second comes over Sunday night into
Monday and then a third with the cold frontal passage later on
Monday. There are some timing and placement differences, but the
higher POPs in the general time frames mentioned above seem to
be on track. Temperatures will average slightly below normal
with highs in the upper 70s to low 80s through Tuesday.

Tuesday into Wednesday looks to be mostly dry with low end POPs
returning for Wednesday afternoon.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1236 PM CDT Thu Jul 4 2024

A disturbance continues to lift northeastward across eastern
Iowa early this afternoon. All TAF sites in eastern Iowa are VFR
with ceilings between 6 to 10kft. Light showers are forecast to
move across the area through mid afternoon with MVFR ceilings
and visibilities possible in the strongest showers. Placed a
tempo group at KCID, KDBQ, and KMLI to account for these
showers.

The focus then shifts to a line of storms that is forecast to
develop and move from west to east between 02 and 08 UTC.
Placed a prob30 group at all TAFs for a two hour windows as
the line moves across the area. There is lower confidence in
the intensity of these storms and the coverage especially for
KBRL. Winds will switch to the west behind a cold front after 06
UTC with gusts winds developing after 12 UTC Friday.

&&

.HYDROLOGY...
Issued at 255 PM CDT Thu Jul 4 2024

The forecast crests along the Mississippi River have been
delayed and are now showing a longer duration crest at several
locations due to some rainfall and forecast rainfall upstream.
Most of the crest values have been steady or only minor changes.
Major flooding will be seen across much of the Mississippi
River with long duration crests occurring after July 7th. Keokuk
is expected to get to the Major Flood stage near the 7th or
8th, and Gregory Landing is expected to crest in its Moderate
flood category.

Tributary Rivers:

Over the next 7 days, Moderate flooding will continue on the
Wapsi at Dewitt and minor flooding will continue at Conesville
on the Cedar River.

Wapello on the Iowa River is expected to drop out of flood late
Sunday. At Oakville, backwater from the Mississippi will keep
the level high, in minor flooding, through July 11.

Current projections for additional rainfall through July 10th
appear to be spotty with widespread heavy rain not anticipated
at this time.

&&

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

&&

$$

SHORT TERM...Cousins
LONG TERM...14
AVIATION...Cousins
HYDROLOGY...14