040
FXUS63 KLOT 140059
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
759 PM CDT Fri Sep 13 2024

.KEY MESSAGES...

- Outside of a small chance for a few showers west of I-39 this
  weekend, dry conditions and summer-like warmth will persist
  through at least next week.

&&

.UPDATE...
Issued at 759 PM CDT Fri Sep 13 2024

Minor update made earlier this evening to add isolated showers
for locations south of a Peru to Lafayette line. Otherwise, no
changes to going forecast with dry and mild conditions
continuing under partly cloudy skies for the remainder of the
cwa.

Radar depicts isolated showers occurring along the ILX/LOT
border region this evening, along a NW-SE moisture gradient
within in a region of weak DCVA and warm advection north of the
decaying circulation of post-tropical cyclone Francine. High-
res guidance indicates a gradual weakening of 25 kt southeast
850 mb flow tonight, as well as diurnal weakening of marginal
low-level instability. Expectation is that isolated showers will
become even less numerous over the next couple of hours, with
dry weather from late evening through the overnight hours.
Focus for isolated/widely scattered diurnal showers then shifts
to western IL Saturday afternoon, particularly along/west of the
I-39 corridor.

Ratzer

&&

.DISCUSSION...
Issued at 154 PM CDT Fri Sep 13 2024

Post Tropical Cyclone Francine will continue to decay across
the mid-Mississippi River Valley through this weekend. Periods
of associated mid to upper-level cloud cover will filter over
the area during this time. An axis of Gulf moisture advecting
around the system will bring of ribbon of higher moisture into
western Illinois on Saturday that may support isolated showers
and perhaps a stray lightning strike during the afternoon. Have
maintained some 10-15% PoPs west of I-39 as a couple weak
inverted trough axes may provide subtle forcing during the
afternoon, but overall conditions favor a dry forecast for the
area through the weekend.

Ongoing tropical activity in the southeastern states and a
prominent ridge over the Great Lakes region has continued to
foster mid-level blocking across the central and eastern CONUS.
With another tropical system poised to develop off the Carolinas
early next week before drifting N/NNW across the Mid-Atlantic,
the overall flow will remain more or less blocked. This should
keep our area firmly situated on the western extent of an
expansive and persistent surface ridge. Beyond the small chance
for a few showers this weekend, the forecast will remain dry
through next week. Daytime highs in the mid to locally upper 80s
and lows in the upper 50s to mid 60s will be common amid
southeast to easterly winds. Worsening drought conditions will
therefore be the main focus through the forecast period with
nearly our entire forecast area in D0 (abnormally dry) status
and a couple small areas now in D1 (moderate drought) status.

Kluber

&&

.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 613 PM CDT Fri Sep 13 2024

No significant aviation weather concerns through the TAF period.

Forecast area remains on the western periphery of high
pressure, surface and aloft, centered over the eastern Great
Lakes region. Low-level east winds and subsidence within the
region of high pressure (northeast of decaying tropical remnants
off to our south) will make for persistent VFR conditions and
modest east winds through the period. A few spotty showers along
the northern edge of the tropical system will remain well south
and west of the terminals.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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