Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 151608
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
1108 AM CDT Fri Mar 15 2024

.KEY MESSAGES...

- High probability (greater than 50% chance) of wind gusts over
  30mph everywhere north of I-70 on Saturday.

- A brief shot of cold weather will arrive early next week with a
  60-100% chance of low temperatures dipping into the 20s across
  all of central and southeast Illinois both Sunday night and
  Monday night.

- Next rain chance will hold off until the end of next week.

&&

.UPDATE...
Issued at 1101 AM CDT Fri Mar 15 2024

The forecast remains well on track for this afternoon. Satellite
trends show diminishing cloud cover, while regional sfc obs
indicate slowing winds. This all thanks to subsidence/high
pressure behind yesterday`s storm system. Nevertheless, still
tracking a swift-moving disturbance digging toward the Great
Lakes, which will bring a breezy conditions Saturday and much
cooler temperatures Sunday.

MJA

&&

.SHORT TERM...(Today through Saturday)
Issued at 237 AM CDT Fri Mar 15 2024

07z/2am surface analysis shows a cold front sinking southward
toward the Ohio River while widespread post-frontal cloudiness
lingers across central Illinois. HRRR/RAP forecasts suggest skies
will become partly to mostly sunny northwest of the Illinois River
around Galesburg by sunrise...then further E/SE to the I-55
corridor by midday and across the remainder of the KILX CWA by
mid-afternoon. Northeasterly winds will initially gust 20-25mph,
but will decrease this afternoon as a ridge of high pressure
currently extending from the Northern Rockies to Ontario builds
southward into the region. High temperatures will be considerably
cooler than yesterday in the middle to upper 50s. As the high
drifts overhead and winds become light, low temperatures tonight
will dip into the middle 30s. The ridge will quickly shift E/SE
into the Ohio River Valley on Saturday as a stronger cold front
drops out of Canada. Given the tightening pressure gradient
between the retreating high and approaching front, gusty W/SW
winds will develop. NAM forecast soundings indicate deep-layer
mixing up to 5000-6000ft, which will tap into a 40-45kt 925mb jet
ahead of the boundary. 00z Mar 15 HREF shows a high probability
(greater than 50% chance) of gusts exceeding 30mph everywhere
north of I-70...with a 40-60% of gusts over 35mph east of I-55 and
north of I-70 Saturday afternoon. With a good deal of sunshine
and strong W/SW flow, temperatures will rebound into the lower to
middle 60s.


Barnes

.LONG TERM...(Sunday through Thursday)
Issued at 237 AM CDT Fri Mar 15 2024

Strong cold front will drop through the region Saturday
night...introducing a period of below normal temperatures early
next week. GFS shows 1000-500mb thicknesses dropping as low as
516dm by Monday morning, which will translate to the chilliest
weather central Illinois has experienced in weeks. High temperatures
will drop into the 40s on Sunday, then may struggle to even reach
40 degrees in many spots on Monday. Overnight low temperatures
both Sunday night and Monday night will drop below freezing. 12z
Mar 15 LREF indicates a high probability (60-100% chance) of temps
below 30 degrees both nights...with lower probabilities (30-50%
chance) of readings below 25F along/north of I-72 Sunday night and
along/east of I-55 Monday night. Anyone with tender vegetation
emerging outside, will need to take protective measures both
nights.

The cool airmass will be short-lived however, as rising upper
heights and a return to S/SW flow will help boost high
temperatures back into the 50s Tuesday through Thursday. Dry
weather will prevail through much of the extended until a weak
system pivots into the region and brings a few showers by
Thursday.

Barnes

&&

.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 524 AM CDT Fri Mar 15 2024

MVFR ceilings have scattered along/west of I-55 early this
morning, but persist further east. With boundary layer winds from
the NE and plenty of upstream low clouds northeastward to Lake
Michigan, think KDEC/KCMI will maintain MVFR until later this
morning when winds begin to back to N/NW. Have scattered the low
ceilings at both sites at 15z accordingly. After that, VFR
conditions will prevail at all terminals through the remainder of
the 12z TAF period. Winds will initially be N/NE with gusts of
15-20kt, then will back to NW and decrease to 10kt or less by late
afternoon. Winds will then back to SW tonight.

Barnes

&&

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

$$


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