772
FXUS63 KDVN 261935
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
235 PM CDT Sun May 26 2024

.KEY MESSAGES...

- There is a potential for strong to severe storms Monday
  afternoon.

- A change in the flow pattern aloft will bring a period of
  quiet weather to the area for part of the coming work week.

- Several weak disturbances in the flow aloft will bring a risk
  of rain to the area again next weekend.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 233 PM CDT Sun May 26 2024

Isolated showers or storms are possible through sunset as the
atmosphere continue to recover from the morning rain. Mid-level
lapse rates are fairly stable but steeper lapse rates are beginning
to arrive in concert with the upper low and vort max.

With peak heating (roughly 3-5 PM in the warm season), storms may
still fire mid to late afternoon with areas east of the Mississippi
favored. Overall coverage looks to be low (15 to 30 percent) with
any convection dissipating quickly with sunset. The potential is
there for a couple of strong storms to develop that would pose a
risk of hail and locally gusty winds.

After sunset dry conditions will be seen for the entire area.

On Monday the next upper level disturbance will arrive around mid-
day. This disturbance is expected to generate diurnal showers and
storms for the afternoon and potentially into Monday evening. With
lapse rates steepening through the day, the potential is there for
some strong to severe storms during the afternoon. If severe storms
develop the primary risk looks to be damaging winds with hail a
secondary risk.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 233 PM CDT Sun May 26 2024

Monday night and Tuesday
Assessment...medium confidence

There may or may not be some lingering showers and storms until
sunset Monday evening. Overall, much of the area will be dry Monday
night.

On Tuesday another upper level disturbance will move through in the
flow aloft. Although the forcing is weak the relatively wet ground
should provide enough moisture through evapotranspiration to induce
diurnal showers and thunderstorms Tuesday afternoon.

Overall coverage will be on the low side (20-30 percent) with areas
along and north of I-80 being favored.

Tuesday night through Thursday night
Assessment...high confidence

The model consensus has dry conditions across the area Tuesday night
through Thursday as an upper level high builds into the Midwest.
Temperatures will slowly trend to and then slightly above normal.

Thursday night will be interesting. The deterministic runs and more
ensemble members are indicating dry conditions. While the model
consensus still does not show this, pops have been lowered into the
20-25 percent range and confined to areas west of the Mississippi.

Friday through Sunday
Assessment...medium confidence

Given the overall trend with deterministic runs and the respective
ensemble runs of the models, pops are slowly being lowered during
the day Friday. If this trend continues over the next several days,
the prospects of Friday morning being dry would increase
considerably that may extend into Friday afternoon.

Based on the trends of the deterministic runs and ensembles, Friday
night into Saturday generally looks to be the most likely time to
see another round of rain. While the overall areal coverage is only
30-40 percent the time frame of Friday night into Saturday looks to
be the favored time for rain.

Saturday night rain may linger into the evening hours before slowly
dissipating. Interestingly, there is another weak upper level
disturbance in the flow aloft arriving on Sunday. Although the
forcing is weak, if sufficient moisture is available there would be
a low risk (20-30 percent) for showers and a some thunderstorms.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1232 PM CDT Sun May 26 2024

Some isolated to possibly scattered SHRA/TSRA may occur through
02z/27 across eastern Iowa and northern Illinois. However the
probability of a TAF site being impacted is 10 percent at best.
Otherwise IFR/MVFR conditions will slowly improve to VFR through
03z/27 from southwest to northeast. After 03z/27 expect VFR
conditions as high pressure builds into the Midwest. After
18z/27 and upper level disturbance is expected to generate
isolated to scattered SHRA/TSRA.

&&

.HYDROLOGY...
Issued at 1232 PM CDT Sun May 26 2024

Swaths of 1-2 inches of rain occurred overnight and early this
morning in the headwaters and portions of the channels of the
Wapsipinicon, Cedar and Iowa River basins. This will prolong
high water levels and minor to major flooding on these rivers
from the main channels to the confluence of the Cedar and Iowa
Rivers, and Iowa and Wapsipinicon Rivers with the Mississippi
River. This routed water will also lead to further rises on the
mainstem Mississippi River, with many locations nearing action
stage through midweek from Dubuque (DBQI4) down through Muscatine
(MUSI4) while minor flooding is expected in many locations from
Keithsburg (KHBI4) to Gregory Landing (GGYM7). Please refer to
the latest Flood Statements and Flood Warnings for more details.

The forecast will have chances for sporadic rains over the next
couple of days, but significant rainfall is not expected.
Beyond, it looks to turn more active heading into the first
week of June. The Climate Prediction Center has the area favored
for near normal rainfall June 2-8.

&&

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

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...08
HYDROLOGY...McClure