204
FXUS63 KDVN 151958
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
258 PM CDT Thu Aug 15 2024

.KEY MESSAGES...

- A severe risk remains for the 6 pm to 11 pm timeframe with all
  modes of severe weather possible if storms develop.

- A pattern change will bring mainly quiet weather to the area
  Saturday night through next Thursday. Temperatures look to
  be near normal.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 258 PM CDT Thu Aug 15 2024

Tonight, uncertainty remains with possible storm development
after 6 pm in western parts of the CWA. Trends of the HRRR have
been to delay the time of development, which is now showing
closer to 6 or 7 in our western CWA. The NAMNEST has only shown
some activity in the far SW after 8 pm. MUCAPE values of 2 to 3K
J/kg build into the area late this afternoon and evening. This,
along with mid level lapse rates over 7 C/km and moderate shear,
will all some supercells to be possible with strong winds,
hail, and tornadoes all a threat. The caveat is whether the
clouds that have been over the area most of the day will clear
in time for needed heating for development. Some temps in the
low 80s are seen in south central IA as of 2 pm. Moisture is
plentiful, with dew points in the lower and middle 70s area
wide. Due to these uncertainties, kept POPs in the chance
category. As for timing, it looks like areas west of the MS
River will see activity from 6 pm to 10 PM, with the eastern CWA
seeing it 9 pm to about midnight or 1 am. Overnight, any
showers or storms will exit to the east. Some patchy fog is
possible overnight, but left mention out of grids for now. Lows
will be in the 60s.

Friday, a secondary cold front will sweep across the area as
the surface low moves across northern WI. Sunshine will prevail
south of Highway 30, while clouds and even some shower and
thunderstorm chances will be possible to the north. SPC has NW
IL in a marginal risk area for wind gusts and hail. Highs will
top out in the lower 80s north to upper 80s south.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 258 PM CDT Thu Aug 15 2024

Largely quiet weather dominates the Quad Cities CWA in the long
term as the upper low currently situated over the ND/MN border
slowly migrates east over the next several days putting the area
into northwest flow. Temperatures are expected to sit generally
right around average through Tuesday with highs in the upper
70s/lower 80s and lows in the upper 50s/lower 60s. Temperatures,
combined with manageable humidity levels (especially early next
week), should make for overall pleasant weather. The focus over
this weekend will be on the upper low Saturday as it pushes
into Lower Michigan, which could provide enough forcing for a
few wrap-around showers over the far eastern portions of our
area. The most favored time for shower activity comes during the
daytime hours on Saturday. Still, generally low chances (<35%)
of precipitation exist, so not expecting anything in the way of
widespread rainfall.

Shower chances diminish Sunday and beyond as the upper low exits
and high pressure builds in. Mid-level ridging builds in by midweek
which will nudge temperatures back up into the upper 80s late
week.

Siemianowski

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1239 PM CDT Thu Aug 15 2024

IFR to MVFR ceilings with low clouds will continue this
afternoon with some breaks towards the late afternoon and
evening. If some clearing is realized, some showers and
thunderstorms are expected to develop and traverse the area
during the evening hours. This would bring some MVFR conditions
in storms, but otherwise VFR conditions should prevail. MLI and
BRL will have the best chance for seeing showers or storms so
introduced a prob30. CID might see some storms near 00Z before
they more east, but opted to leave mention out due to the
uncertainty of development and placement. Overnight some
visibility reduction into MVFR category may be seen, but left
mention out of TAFs at this time.

&&

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

&&

$$

SHORT TERM...14
LONG TERM...Siemianowski
AVIATION...14