482
FXUS63 KDVN 262010
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
310 PM CDT Wed Jun 26 2024

.KEY MESSAGES...

- Quiet weather across the area through Thursday with lower
  dewpoints and humidity.

- Thunderstorms are possible Friday into Friday night. There is
  a Slight Risk for severe thunderstorms along and west of the
  Mississippi  River with a Marginal Risk to the east. There
  will also be the threat for heavy rainfall.

- There is another round of showers and storms Monday through
  Tuesday.

- Temperatures will be near to slightly below normal through
  Monday before another warming tend begins.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 126 PM CDT Wed Jun 26 2024

A cool front has exited into Missouri and Illinois with
dewpoints behind the front dropping into the mid to upper 50s.
Temperatures have rebounded quickly in the wake of clouds and
morning showers and isolated storms. At 2 PM, temperatures
range from 82 degrees at Macomb to 90 degrees at Monticello.

High pressure is forecast to move across the area tonight into
Thursday and bring quiet weather and a respite from the heat
and humidity. Skies will be clear overnight and allow
temperatures to cool into the lower to mid 60s across the area.

As high pressure shifts to the east on Thursday, clouds are
forecast to move into the area during the afternoon hours ahead
of a storm system in the Plains. High temperatures on Thursday
will range from the upper 70s in counties along the Highway 20
corridor to the lower 70s in the counties along and south of
Interstate 80.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 126 PM CDT Wed Jun 26 2024

Amplified zonal flow will continue across the continental US through
the long term period with tamped down ridging centered over the
southern Plains. This will result in chances for showers and
storms early Friday into Saturday morning and again Monday into
Tuesday.

Thursday night, models depict a subtle shortwave trough at 500 moving
across the area Friday morning. This would mainly be elevated
thunderstorms in a decaying stage with lower values of
CAPE across the area. In the wake of the morning activity, a
warm front is forecast to move across the area during the
afternoon. This will help to promote airmass recover across the
area. Moisture and CAPE builds during this time as well as
increasing deep layer shear. The Storm Prediction Center has a
Slight or level 2 out of 5 Risk of severe storms with a Marginal
Risk to the east of the River. In addition to the severe
threat, models are showing precipitable water values ranging
from 2.00 to 2.25 so heavy rain will be possible with any storms
that move across the area. The threat for showers and storms
continues into Saturday morning.

High pressure at the surface and aloft is forecast to build
into the area for the remainder of the weekend and pull cooler
air into the region. High temperatures on Sunday will be in the
70s across the area.

Models show another storm system moving into the Upper Midwest
Monday night into Tuesday with once again deeper moisture
available as precipitable water ranges from 2.00 to 2.25 inches
and CAPE builds across the area. This will bring the potential
for another round of storms with heavy rain. It is to early to
determine the several potential at this time.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1238 PM CDT Wed Jun 26 2024

High pressure is forecast to move across the area through the
TAF period resulting in VFR conditions. Clouds will begin to
build into the area late in the period ahead of a storm system
that is approaching the area from the west. Northerly winds will
be gusty this afternoon but decrease to around 5 knots after 00
UTC.

&&

.HYDROLOGY...
Issued at 1207 PM CDT Wed Jun 26 2024

Changes...

Flood warnings have been issued for the Mississippi River from
Keokuk, IA down through Gregory Landing, MO. The flood warning
for Gladstone, IL (L/D 18) has been raised to the major
category.

Flood warnings have been issued for the Cedar River for Cedar
Bluff and Conesville, IA.

Flood warnings have been issued for the Iowa River from Wapello
to Oakville, IA.

Discussion...

The Mississippi continues to rise with multiple locations
expected to reach flood stage by Friday. The flood crest is still
north of La Crosse, WI so much of the Mississippi will likely
remain above flood stage through the middle of July. Crests on
the Mississippi north of L/D 15 look to occur around the Forth
of July. South of L/D 15 crests will occur after the Forth of
July.

There is a high to very high probability that the Mississippi
will reach major flood stage before cresting from L/D 15 down
through L/D 17 in the July 3-10 time frame.

On the Cedar River the Crest is currently located in the Cedar
Falls area with crests occurring in Vinton, Palo and Cedar
Rapids areas in the Friday to Saturday time frame.

Water from the Cedar River will bring the lower Iowa River above
flood stage downstream from the confluence with the Cedar River.
Right now the Iowa River at Columbus Junction is not forecast to
reach flood stage. That may change depending upon where and how
much rainfall occurs late Thursday night into Friday night.

More rainfall is expected Thursday night through Saturday which
will have the potential to be heavy. This rainfall is not
included in the current river forecasts. As such, one should
expect changes to the crest forecasts based on the forecast QPF.

Outlook...

The overall weather pattern looks to remain quite active through
the Forth of July and potentially into the middle of July. The
MJO which has been weak to non-existent for much of June is
forecast to strengthen over the next 10 days and is forecast to
move from phase 2 to phase 4 over the next two weeks. Phase 3
and 4 of the MJO climatologically correlates to above normal
rainfall for the upper Midwest and Mid-Mississippi Valley.
Indeed the Climate Prediction Center has a 40-50 percent
probability of above normal precipitation July 3-9.

&&

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

&&

$$

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