425
FXUS63 KDVN 071029
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
529 AM CDT Sun Jul 7 2024

...Updated for 12z Aviation...

.KEY MESSAGES...

- Active/unsettled through early week with periodic showers and
  storms.

- Depending on the track, the remnants of tropical cyclone Beryl
  could bring rain to far south/east portions of the service
  area Tuesday night into Wednesday.

- Temperatures generally near normal through much of next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 333 AM CDT Sun Jul 7 2024

Broad mid/upper level troughing extends from the Northern Rockies
to the western Great Lakes early this morning. Embedded within
was a pronounced shortwave over eastern North Dakota and western
Minnesota. Additional smaller perturbations with some convective
augmentation were noted in water vapor imagery shifting east
from the Missouri River Valley, and also lifting from south
central to northeast Iowa. These lower amplitude waves will
continue to foster chances for showers and storms today,
initially greatest coverage north/west of the Quad Cities but
evolving near QC metro to southeast Iowa later this morning into
early PM. Sub-severe gusty winds are possible with outflows,
and with convective augmentation of shortwaves we may have to
also watch for some wake low potential. We could see a period of
decreasing coverage of showers/storms by mid to late afternoon
if timing of the waves holds. This evening/tonight, additional
shortwave energy noted upstream across portions of eastern
Colorado/ Nebraska will shift eastward through the mean trough
axis bringing a renewed increase in shower/storm coverage aided
by vorticity advection and a strengthening 20-30 kt LLJ and
attendant warm/moist advection. Deep layer shear looks marginal
at 20-25 kt 0-6km to preclude an organized severe weather
threat, however given progged steep low level lapse rates and
around 1000-1500 j/kg of CAPE 0-1km we may need to keep an eye
out for some gusty winds potentially near severe especially if
shear can be augmented by the approaching wave to foster more
robust updraft potential. 00z HRRR neural network interestingly
does highlight some very low probabilities of 50+ kt wind gusts
south/west of the Quad Cities 22z-02z, and 00z HREF ensemble max
gusts show potential for 50-60 kt. Low confidence on occurring
but something to monitor for should the kinematic and thermodynamic
environment become conducive. Localized heavy rain amounts of 1
inch or more are possible with any slower moving or repeated storms.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 333 AM CDT Sun Jul 7 2024

We continue with an unsettled/active early week period, as the
positively-tilted mid/upper level trough progresses eastward
toward the western Great Lakes by Tuesday. A series of
shortwaves will continue to traverse the region along the SW to
NE oriented flow aloft. These disturbances coupled with a SW
LLJ and forcing along a slow moving cold front will foster
periodic showers and storms, especially near and east of the
Mississippi River into Tuesday. Locally heavy rains are possible
with any repeated or slow moving activity, while the organized
severe weather threat appears low.

The progression of the broad mid/upper level trough will play
a pivotal role in determining whether or not we see any rain
and potentially gusty winds from the remnants of TC Beryl
Tuesday night into Wednesday. The latest forecast from NHC and
super ensemble mean track would take the remnant low from south
of St Louis to northwest Ohio Wednesday into Thursday. The
surface low tracks from the operational GFS, GEFS mean, and
several members of ECMWF ensemble however, show a track further
north/west, and closer to the western edge of the NHC forecast
cone into northwest Illinois (not something we`re used to
seeing!). To try and account for some potential of a more
north/west track we`ve collaborated with eastern neighboring
offices blending in some CONSAll guidance with NBM to give PoPs
a bit of an increase across far SE portions of the service area
Tuesday night into Wednesday, although staying in the chance
(30-40%) category for now. We`ll continue to monitor the track
of Beryl closely in the next 48+ hours, so stay tuned for
updates.

Heading into late next week and next weekend, the ensemble
guidance supports ridging across the Intermountain West and
Mid-Atlantic with weak troughing from the western Great Lakes
to the Lower Mississippi Valley. This will keep some chances
for precipitation, although nothing too widespread/organized and
perhaps more isolated diurnally driven. Temperatures should
remain near normal into late next week, but by next weekend and
just beyond there are some signs that the western ridge /heat
dome/ may try to build toward the region leading to greater
summer heat potential.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 525 AM CDT Sun Jul 7 2024

VFR conditions will largely dominate, but there will be scattered
shra/tsra throughout the TAF period accompanied by MVFR to IFR
conditions (mainly for visibility). Outside of outflow near
storms winds will generally be light from a southerly direction.

&&

.HYDROLOGY...
Issued at 110 PM CDT Sat Jul 6 2024

Rainfall amounts were less than expected. Therefore, the Mississippi
River is currently cresting at and upstream of Bellevue, IA. The
crest may take 1 to as much as 3 days to pass.  Fulton and Camanche
are forecast to begin cresting Sunday afternoon, with Le Claire,
Rock Island, and Gladstone seeing the crest begin late on Monday.
The remainder of the sites south of the Quad Cities are
expected to crest Tuesday through Friday. Major flooding is
occurring or expected to occur along the Mississippi River from
Dubuque to Keokuk.

Tributary Rivers:

Moderate flooding will continue on the Wapsipinicon River at Dewitt
through Tuesday. It is forecast to briefly drop into Minor Flood
Category midweek, before rising back to Moderate Flood stage on
Thursday.

On the Cedar River at Conesville, minor flooding will continue. It
will see a secondary crest near 14.5 feet late this coming week.

The Iowa River at Oakville is seeing high water levels due to
backwater affects from the Mississippi River. It is forecast to
remain near 11.8 through midweek and then rise to near 12 feet.

A flood watch remains in effect for the Cedar River at Cedar Rapids.
It is forecast to briefly reach the 12 foot flood stage late Monday
afternoon. Confidence remains low.

&&

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

&&

$$

SHORT TERM...McClure
LONG TERM...McClure
AVIATION...McClure
HYDROLOGY...14