135
FXUS63 KDVN 090831
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
331 AM CDT Tue Jul 9 2024

.KEY MESSAGES...

- Chance of showers today for areas along and east of the MS RVR
  from the remnants of TS Beryl. Heavy rain is not anticipated.

- Increasing rain chances (30-50%) Wednesday afternoon/evening
  across much of the area. Severe weather is not expected.
  Additional diurnally driven showers/storms are possible
  Thursday and Saturday.

- Increasing heat and humidity levels beginning Friday and into
  next week. Heat indices well into the 90s and even low 100s
  are forecast Sunday and Monday.

- Moderate to major river flooding continues on the Mississippi
  River with most sites crested or cresting in the coming days.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 312 AM CDT Tue Jul 9 2024

Early morning water vapor loops and radar mosaics show tropical
depression Beryl centered across southwest AR, with its
stratiform precip shield slowly lifting north over southeast MO
and southern IL. The lightning activity associated with Beryl
has been displaced from its center and mostly confined to
western TN attim. A quick look at rainfall amounts in the past 6
hours in AR, show an impressive 2.61" fell from 00-06z at Adams
Field in Little Rock. A little further north of there at 00z, the
PW from the 00z SGF sounding was 1.73" which is near the 90th
percentile per SPC sounding climatology.

Latest NHC track for Beryl has the system moving into southern
IL and into northern IN by 12z Wed. The 00z deterministic and
ensemble runs suggest that the far southeast portions of the CWA
still may receive some rain today, but the heavier QPF will
to our south and east. The local probability matched mean (LPMM)
of the 00z HREF has 3-5" QPF running from near St. Louis, to
Decatur, IL, to Kankakee. For our area, the probability of 1" or
greater rain amounts is only 30% in McDonough and Putnam
counties. Needless to say, rain amounts east of the MS RVR are
forecast between a quarter and a half inch or less.

Regarding temps today, with an expansive cirrus shield and 850mb
temps slightly cooler have lowered highs by a degree or two
which is now closer to the NBM with readings topping out in the
upper 70s/low 80s. Clouds will clear late tonight from west to
east with lows dropping into the low to mid 60s.


&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 312 AM CDT Tue Jul 9 2024

Wednesday...the upper level pattern turns northwesterly, with
the large ridge remaining over the western CONUS. A strong
shortwave will dive south into Iowa bringing an increase in
clouds and precipitation chances. The 00z runs and the latest
RAP have come in a little wetter with this system and PoPs have
increased into the 30-50% range. With CAPE building through the
day in the 1500-2000 J/Kg range and PWs increasing to 1.5"
expect scattered showers and a few thunderstorms to develop in
the afternoon. Shear will be the limiting factor for any severe
risk, but some heavy downpours and small hail may occur in any
of the stronger cells.

Thursday-Saturday...additional weak waves will move through the
flow bringing low diurnally driven chances of precipitation
Thursday and Saturday. Highs will be a few degrees warmer each
day reaching the upper 80s/low 90s by Saturday.

Sunday-Monday...thermal ridge slides east into the forecast area
with 850mb temps rising into the 23-26C range. This will boost
temps into the 90s and combined with dewpoints in the low 70s
(perhaps even higher due to mature corn crop), will push
afternoon heat indices into the upper 90s and low 100s. With the
storm track expected just to our north during this period, heat
headlines may need to be considered for early next week if
forecast trends continue.


&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1218 AM CDT Tue Jul 9 2024

VFR conditions to prevail for most if not all of the TAF cycle
at the terminals. Some guidance was hinting at some MVFR/IFR
fog to develop prior to sunrise at all sites, but with the
expected cirrus shield from TS Beryl overhead, feel this will
not be as widespread as some models indicate. In any case,
introduced some brief MVFR vsbys at CID/MLI/BRL, where recent
rains have moistened the BL. After sunrise, high clouds will
remain, with winds remaining under 6 kts.

&&

.HYDROLOGY...
Issued at 124 PM CDT Mon Jul 8 2024

Precipitation in the next few days, especially in Iowa, is expected
to be dry or very light. Thus, routed flow will continue on all of
our rivers.

The Mississippi River is currently cresting at major levels upstream
of Camanche, IA, and near crest through Illinois City.  The crest
may take 1 to as much as 3 days to pass. From Le Claire to
Burlington, the respective crests will commence within the next 1 to
2 days.

Keokuk is now forecast to crest within Moderate Flood category
beginning Friday.  Gregory Landing is forecast to remain near 19.5
feet through the week.

Tributary Rivers:


The Cedar River at Cedar Rapids crested below flood stage and will
fall over the next several days.

On the Cedar River at Conesville, minor flooding will continue. It
will see a secondary crest near 14.4 feet Wednesday night into
Thursday.

The Wapsipinicon River at Dewitt is forecast to remain in
moderate flooding category through late on Friday.

The Iowa River at Oakville is seeing high water levels due to
backwater affects from the Mississippi River. It is forecast to
remain near 11.4 or 11.5 feet through midweek and then rise to near
12.1 feet late Thursday into Friday.

&&

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

&&

$$

SHORT TERM...Gross
LONG TERM...Gross
AVIATION...Gross
HYDROLOGY...Gunkel