-- Discussion containing changed information from previous version are highlighted. --
042
FXUS63 KDVN 251039
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
539 AM CDT Wed Sep 25 2024

.KEY MESSAGES...

- Warmer than normal temperatures through the weekend then below
  normal next week.

- Higher than normal uncertainty regarding rain chances late
  week and into early next week. Recent trends suggest the
  probability of dry versus rain is about 70/30.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 221 AM CDT Wed Sep 25 2024

Some very patchy fog is possible around sunrise that may briefly
impact the morning commute. Otherwise, expect dry and pleasant
conditions with highs in the 70s today. The quiet and dry conditions
will continue tonight with light winds. Patchy fog is possible again
late tonight that may continue through sunrise Thursday.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 221 AM CDT Wed Sep 25 2024

Thursday through Monday night
Assessment...high confidence on above normal temperatures. Low
confidence on rain.

As mentioned yesterday there will a a Fujiwara effect between the
remnants of Helene and the cutoff upper low. The trend being
depicted over the past 24 hours now suggests that the remnants of
Helene will be absorbed by the cutoff low. The key is where is the
upper low located which will dictate the rain chances for around
here. What is certain is that high level moisture in the form of
clouds will impact the area which could cool temperatures down.

The global models vary with the location of the upper low but are
generally depicting an area from west Tennessee into western
Kentucky. This location is further to the east compared to 24 hours
ago. NHC guidance on Helene does bring the remnants to near the
confluence of the Mississippi and Ohio Rivers by Saturday evening.

The ensembles from the various global models are interesting. There
are 2 members of the GEFS that bring rain into the area Friday into
Saturday night while the other members are considerably further to
the south and east.

All ensemble members from the CMCE/ICON-EPS keep the entire area
dry. As for the ECMWF EPS, a majority of the members keep any rain
well removed to the south and east of the area. There are a couple
of members that have the QPF mean just getting into the far eastern
and southeast areas on Saturday.

If the forecasted position of the cutoff upper low of near the
confluence of the Mississippi and Ohio Rivers is correct, there is a
70-80 percent chance that most of the time period from Thursday
through Monday night will remain dry.

As expected the model consensus is slowly drying out the forecast
and further drying out is expected over the next 24 hours.

Right now the model consensus has dry conditions Thursday through
Friday morning. There is a 20 percent chance of rain south of a
Princeton, IL to Memphis, MO line Friday afternoon but Friday
afternoon has a 70 percent probability of being dry everywhere.

The most likely time period for any rain looks to be in the Friday
night/Saturday time frame. The current model consensus has a 20-40
percent chance of rain with the highest chances in the far east and
south.

As for the Saturday night through Monday night time frame, the model
consensus has 20-30 percent rain chances generally south of a
Freeport, IL to Ottumwa, IA line. The exception is Monday/Monday
night when there is a 20 percent chance of rain everywhere. The rain
chances in the Monday/Monday night time period are tied to the
passing of a cold front through the area.

Tuesday
Assessment...high confidence on dry conditions

The model consensus has dry and cooler than normal temperatures for
the area as a Canadian high builds into the Midwest. Temperatures
may struggle to reach 70 degrees for the daytime high.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
-- Changed Discussion --
Issued at 537 AM CDT Wed Sep 25 2024

Very patchy shallow fog with IFR/LIFR conditions will be seen
through 14z/25. Otherwise expect VFR conditions through 06z/26.
After 06z/26 light winds will bring the risk of patchy shallow
fog with IFR/LIFR conditions.
-- End Changed Discussion --

&&

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

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...08