401
FXUS63 KILX 150035
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
735 PM CDT Tue May 14 2024

.KEY MESSAGES...

- Showers and thunderstorms bringing more rainfall to central Illinois.
  East of I-57 has a 50-80% chance of receiving another inch of
  precipitation by tomorrow morning.

- Localized flooding concerns exist for areas that thunderstorms
  overachieve this evening and overnight. Runoff could cause
  streams and creeks to rise.

- The next opportunity for showers and thunderstorms comes
  Thursday into Friday. (50-75% chance of showers & t`storms)

&&

.UPDATE...
Issued at 735 PM CDT Tue May 14 2024

Latest water vapor imagery shows the upper low just southwest of
St. Louis early this evening, with the surface reflection across
the far south tip of Illinois. Showers remain fairly scattered,
concentrated near and north of I-72/Danville. While the activity
across the northern periphery will continue to diminish with
sunset, showers near and east of I-57 will remain possible through
the night as the surface low wobbles into southern Indiana.
Lightning has been rather sparse, mainly south of I-70 closer to
the surface low. Heavier rain concerns mentioned earlier have been
materializing more over southwest Indiana, and if they were to
occur in our forecast area, they likely would be along a weak
surface boundary that shows up on surface obs and Evansville radar
imagery from near Robinson southwest to Fairfield. However,
showers along that boundary have not been too robust at this point.

Evening forecast updates have mainly been to update the rain
trends through Wednesday, and back off some on the thunder
potential.

Geelhart

&&

.DISCUSSION...
Issued at 306 PM CDT Tue May 14 2024

There is a low pressure system slowly moving across the CWA this
afternoon. It will continue transversing through the evening and
overnight hours, and should exit eastern Illinois by 2-3 AM (07-
08z). Showers and thunderstorms rotate around the low pressure
center east-northeastward across the CWA. Forecast soundings from
the NAM show weak, but long, skinny CAPE for the areas along and
east of I-57. PWAT values are forecast to be 1.25-1.5 inches. The
HREF LPMM is showing some localized areas of 2-4 inches of
precipitation along the IL/IN border and south of I-70. There is a
widespread 50-80% chance for an additional inch of rainfall for this
area by early tomorrow morning.

The area where there could be some concern for any localized flash
flooding appears to be south of I-70. FFG based off of VWX radar is
quite high with the 3 hour FFG being 2.2-2.5 inches. Some of the
showers that are out there have seemed to be overachievers. The MRMS
QPE is showing a 3 hour accumulation in the band of stronger showers
in Greene and Calhoun counties of around 1.5 inches. MRMS seems to
be in line with true observations. Outside of the CWA, where the
stronger band I previously mentioned is, the 24 hour MRMS matches
with reports LSX have received. The runoff precipitation could cause
the local streams and creeks to rise.

The week isn`t a complete wash out but there also isn`t long period
of dry weather. There is going to be rain periodically through the
extended forecast as multiple shortwaves make their way through the
region. The next round of rain comes on Thursday and the scattered
showers and thunderstorms will continue through Saturday. Then the
next substantial chance could arrive Tuesday.

Copple

&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 621 PM CDT Tue May 14 2024

MVFR ceilings have been fairly patchy as of late, but should
expand as the sun goes down across areas east of a KBMI-KSPI line.
HREF probabilities of ceilings below 3,000 feet increase to
around 60-80% by 05Z, with similar numbers for IFR conditions as
well. KPIA mostly stays out of the fray, but will include a TEMPO
period for some MVFR ceilings from about 10-12Z. A steady
increase in ceiling heights is expected beginning late morning,
and most sites should be VFR again by 19-20Z.

Geelhart

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$