368
FXUS63 KDVN 181727
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1227 PM CDT Thu Jul 18 2024

.KEY MESSAGES...

- Much welcomed dry weather through the rest of the work week
  and into the weekend, followed by low slight chance to chance
  pops diurnally Sunday and Monday.

- 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 237 AM CDT Thu Jul 18 2024

Ahhh... Clear skies and temperatures in the lower to mid 50s are
widespread over the Cornbelt this morning.  As stated on the
previous AFD, we could approach some record lows this morning in a
few locations.

Today and tonight, the 1024mb high pressure will be centered right
over our area, resulting in very light winds and temperatures in the
mid to upper 70s, despite plenty of sunshine.  This free Canadian air
vacation looks to last at least through Saturday, with only a slight
rise in temperatures expected in the period.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 237 AM CDT Thu Jul 18 2024

While surface high pressure remains in the Midwest through Sunday, a
weak upper low is forecast to slowly drop into the Plains, and shift
east into Iowa for Sunday and Monday, as it weakens. At the very
least, this will allow for more of a diurnal increase in cloud cover
each day, but should also allow for a isolated to scattered shower /
storm chance.  The flow aloft will be weak, and moisture depth
appears limited. Thus, these pop/drop showers should not move
quickly, and would only offer an isolated rainfall potential.

Temperatures will be warming only modestly during this period, with
dew point temperatures rising to only the lower to mid 60s, which is
largely driven by evapotranspiration as opposed to moist advection.
Highs in the lower to mid 80s are forecast Monday through Thursday.
Lows in the lower to mid 60s are expected.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1212 PM CDT Thu Jul 18 2024

VFR conditions expected through the TAF cycle. Scattered fair wx
Cu between 3500-5000ft will dissipate after sunset. Surface high
center will be east of the terminals after midnight tonight.
Additional Cu can be expected Friday afternoon.


&&

.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.

&&

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

&&

$$

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