746
FXUS63 KDVN 171905
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
205 PM CDT Wed Jul 17 2024

.KEY MESSAGES...

- Pleasant and dry conditions tonight, with well below normal
  temperatures.

- Much welcomed dry weather through the rest of the work week
  and into the weekend.

- Moderate to major river flooding continues on the Mississippi
  River. The Rock River is now expected to see moderate
  flooding by the end of the week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 205 PM CDT Wed Jul 17 2024

A large 1023mb surface high to move over the Midwest overnight
tonight bringing a rather dry and cool airmass to the region.
Taking a look at 12z upper air data, the 850mb temp at INL was 6C or
near its 10th percentile per SPC sounding climatology.
This air will advect into WI overnight tonight, with RAP 850mb temps
dropping into 7-9C range locally. This also will be near the 10th
percentile of our soundings here at DVN. So long story short, it
will be a very nice and cool night for July standards.
In fact, with clearing skies and light winds, temperatures and
dewpoints will drop into the low to mid 50s. This will be within
shouting distance to record lows for the 18th. See climate section
below for details.

Thursday...surface high to be centered over the region, with some
more fair wx Cu developing in the afternoon. Highs will top out in
the upper 70s.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 205 PM CDT Wed Jul 17 2024

Comfortable and dry conditions are expected Friday and Saturday, as
surface high pressure drifts east into IN/OH/MI. An upper level wave
will drop southeast into the Great Plains Saturday afternoon and
evening, bringing an increase in clouds. Better moisture and lift
will be just to our west and have kept PoPs below mention through
Saturday. The NBM and the LREF 100 member ensemble probabilities of
measurable QPF also support this. Small slight chance PoPs in
our far western counties are seen Sunday and Monday, as the open
upper wave rotates just to our west. Moisture will be the
limiting factor. Most of the area should remain dry through the
weekend and into next week.

Looking ahead, the upper air pattern remains unfavorable for any
widespread rainfall. A few weak waves early in the week may bring
some chances for rain, but the threat for any strong storms remains
low. Temperatures will be near seasonable, with highs in the 80s and
lows in the 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1133 AM CDT Wed Jul 17 2024

VFR conditions are expected through the TAF cycle. Some fair
weather cumulus clouds will expand across the eastern IA and
northern IL this afternoon, but remain SCT above 3kft.
Decreasing clouds and winds under 5 kts will be seen after
sunset.

&&

.HYDROLOGY...
Issued at 1125 AM CDT Wed Jul 17 2024

The Mississippi River has crested at all sites, with some reaches
continuing to experience somewhat stalled falls or steady trends
over the next few days due to recent bouts of heavy rain, local run-
off, and tributary input. L&D 19 at Keokuk and Gregory Landing will
even experience secondary rises into the weekend.

Tributary Rivers:

The recent rounds of heavy rain on the Rock River basin will
continue to produce significant rises on the Rock, but after
assessing the extent of run-off and upstream flow trends, Joslin and
Moline are now projected to remain below the Major flood stage. The
Rock at Como will be in Minor flood through Friday evening.

The Pecatonica River is projected to rise into Minor flood at
Freeport IL Friday night.

The lower Wapsipinicon River near Dewitt, IA performed a secondary
crest around 11.2 feet yesterday/Tuesday evening, but is now
dropping below flood stage. With the dry weather into the weekend,
the Wapsi is now expected to remain in the decline mode and remain
below the flood stage.

Backwater effects from the Mississippi River will keep the lower
Iowa River just below flood stage through early next week.

Further south, torrential rainfall and run-off from Monday night may
produce a large rise to action stage on the La Moine River near
Colmar in west central IL by Thursday. But the extent and speed is
still somewhat uncertain and will have to watch river rise trends
over the next 24 hours.

&&

.CLIMATE...
Issued at 205 PM CDT Wed Jul 17 2024

Record Low Temperatures:

July 18:
KBRL: 53 in 1924
KCID: 49 in 2009
KDBQ: 51 in 1979
KMLI: 54 in 2014


&&

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

&&

$$

SHORT TERM...Gross
LONG TERM...Gross
AVIATION...Gross
HYDROLOGY...12
CLIMATE...Gross