364
FXUS63 KDVN 270838
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
338 AM CDT Fri Sep 27 2024

.KEY MESSAGES...

- Gusty northeast winds are expected today, up around 30 mph at
  times through the afternoon.

- Temperatures this weekend will be warm by late September
  standards and it will become more humid.

- A return to cooler, more seasonable weather is forecast for
  the first few days of October behind a cold front.


&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 315 AM CDT Fri Sep 27 2024

Today: SPC mesoanalysis and GOES WV imagery showed a large cut-
off upper low centered over the Lower Mississippi Valley near
western Tennessee and northwest Arkansas. Hurricane Helene has
been moving quickly to the north tonight, already into southeast
Georgia. It has now weakened to a Category 1 after making
landfall earlier tonight as a Category 4. The tropical low will
phase with the cut-off mid-level low positioned slightly to the
west. The surface low will gradually pivot from the southeast
into Kentucky, increasing the surface pressure gradient across
eastern Iowa and northwest Illinois. Expect increasing NE to NNE
winds with gusts between 25 - 35 mph (highest east of the
Mississippi River). The gusty winds and dry conditions will
lead to an elevated fire weather threat in cured agricultural
fields, which is slightly favored east of the Mississippi River
due to higher winds.

Tonight - Saturday: The majority of the rain associated with
the transitioning tropical to post-tropical system is forecast
to hold southeast of the area. However, continual moisture
advection via ESE flow aloft may support a brief period of
mainly light rain (20-40%) across the far east-central to
southeast counties late tonight into Saturday morning. Any
rainfall amounts would be light, if anything occurs at all. For
temperatures, expect highs to range from the mid 70s to lower
80s today and Saturday, warmest in the west and coolest in the
east.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 315 AM CDT Fri Sep 27 2024

A weakening post-tropical Helene will stay to our southeast over
the weekend as ridging aloft builds into the Midwest. We can
expect highs in the upper 70s to lower 80s for most of eastern
Iowa and northwest Illinois for Sunday - Monday. Moisture will
also increase for Sunday and Monday with dewpoints in the upper
50s to lower 60s. A cold front will move through the Midwest
Monday into Tuesday AM, ushering in a more fall-like airmass.
Highs in the 60s/lower 70s and lows in the 40s/50s are forecast
for Tuesday and Wednesday, right on schedule as we turn the
calendar to October!

The extended period of abnormally dry conditions will continue
through at least this upcoming Thursday with high pressure
building in behind the early week cold front. The NBM is showing
dry conditions through Friday, and the GEFS and EPS have very
low probabilities for measurable rainfall through this same period
(less than 20% for most locations).

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1250 AM CDT Fri Sep 27 2024

Gusty NE to NNE winds will develop Friday morning as the tropical
system "Helene" shifts northwestward into the Ohio Valley. The
strongest winds are expected at MLI and BRL with peak gusts of
25 to 30 kts possible. VFR will prevail through the period with
no precipitation expected.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Uttech
AVIATION...Uttech