366
FXUS63 KDVN 051735
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1235 PM CDT Fri Jul 5 2024

.KEY MESSAGES...

- Isolated to scattered showers today.

- Periodic chances for rain/storms through early next week with
  temperatures near to a little below normal.

- Moderate to Major River Flooding continues.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 315 AM CDT Fri Jul 5 2024

Last of the low level WAA band of showers and storms is exiting
our NW Illinois counties early this morning. Light winds and
abundant moisture aided by recent rainfall will lead to some
fog, dense in some areas particularly across portions of
E Iowa north of I-80 and NW Illinois north of I-88 per obs,
reports and Nighttime Microphysics satellite imagery. The fog may
persist until winds begin to pick up from the west toward
daybreak as the front passes. Otherwise, focus for later today
will shift to an upper level low on water vapor imagery over
Minnesota. As this low tracks eastward today it will usher in a
surface cold front. Attendant wrap around cool advection and a
bump in the surface gradient will contribute to at times breezy NW
winds today and burgeoning stratocumulus. Cyclonic vorticity
advection will also foster isolated to scattered showers,
burgeoning this afternoon as steepening low level lapse rates
coincident with peak diurnal heating allow parcels to tap the tall
skinny SBCAPE profiles. This could lead to a few brief/pulse
storms as hinted at in ECMWF lightning flash density forecast.
With WBZ heights progged sub 10kft AGL can`t totally rule out some
brief small hail with the strongest cores. The shower activity
will diminish this evening with the loss of diurnal heating and
NVA building in.

Highs today will be modulated by the extent of solar insolation.
The greatest duration is anticipated across our southern
counties pushing highs in the upper 70s to lower 80s, while the
lowest duration far north/west should limit highs there to
around 70 or the lower 70s. Lows tonight under clear to partly
cloudy skies will generally be in the upper 50s to lower 60s.
A few mid 50s are possible portions of NE Iowa, with any
duration of BL decoupling and clear skies being in closer proximity
to surface ridging.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 315 AM CDT Fri Jul 5 2024

The active pattern is expected to continue through early next
week. A developing broad longwave trough over the Northern
Plains/Upper Midwest will shuttle several shortwaves through
the region leading to periodic chances for showers and storms.
Sunday into Monday looks to be the period that harbors the
greatest shower/storm potential aided by diurnally building
instability and a stronger mid level wave. At this time not
seeing any anomalously high PWAT or excessive rainfall signal
in NAEFS or ENS, which is good news given the ongoing moderate
to major river flooding. There`s also signs that we could be
looking at a drier pattern evolving mid month, as the
deterministic and ensembles are starting to agree on a more
amplified western CONUS ridge and an eastern CONUS trough.
Between northwest flow and potential of the ridge spilling over
at times into the central CONUS, a drier pattern may evolve
while some periods of typical summer warmth/heat possible with
any ridging episodes. This is eluded to in the very recent
8-14 day outlooks from CPC and also the most recent Weeks 3-4
outlooks.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1232 PM CDT Fri Jul 5 2024

An upper level disturbance rotating through eastern Iowa and
northern Illinois will bring isolated to scattered SHRA through
00z/06. A rogue TSRA cannot be ruled out but the probability of
that occurring is 10 percent and thus was not included in the
18z TAFs. Outside of the SHRA VFR conditions can be expected.
After 01z/06 VFR conditions will be seen as high pressure builds
into the Midwest.

&&

.HYDROLOGY...
Issued at 1141 AM CDT Fri Jul 5 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
in timing. Major flooding is forecast along most of the
Mississippi River. 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
Wapsipinicon River at Dewitt and minor flooding will continue
at Conesville on the Cedar River. A flood watch remains in
effect for the Cedar River at Cedar Rapids due to rises from
routed flow and forecast rainfall.

Wapello on the Iowa River is expected to drop below minor flood
stage this afternoon. At Oakville, backwater from the
Mississippi will keep the level high, in minor flooding, through
July 11.

Within banks rises are occurring on the English River at Kalona
and on the North Skunk River at Sigourney.

Over the next seven days widespread heavy rain is not expected.

&&

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

&&

$$

SHORT TERM...Cousins/McClure
LONG TERM...McClure
AVIATION...08
HYDROLOGY...Cousins