385
FXUS63 KLOT 222009
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
309 PM CDT TUE APR 22 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS CONTINUE TO BE IN THE FORECAST
TONIGHT, WITH A MARGINAL RISK FOR SEVERE STORMS LATE THIS
AFTERNOON/THIS EVENING.
- WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED INLAND THROUGH
WEEK'S END, THEN TURNING MORE SEASONABLE FOR THE WEEKEND.
- CHANCES FOR SEVERE STORMS RETURN EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 309 PM CDT TUE APR 22 2025
THROUGH WEDNESDAY:
ZONAL FLOW ALOFT EXISTS ACROSS THE AREA TODAY, WITH UPPER LEVEL
LOWS ACROSS NORTHERN MN AND QUEBEC CURRENTLY. AT THE SURFACE, A
WARM FRONT IS LIFTING NORTHEAST ACROSS NORTHERN IL THIS
AFTERNOON...USHERING IN WARMER AND MORE HUMID AIR INTO THE
AREA. EXPECT SHOWERS AND THUNDERSTORMS TO MOVE IN/REDEVELOP
ACROSS THE FORECAST AREA BY LATE AFTERNOON. BELIEVE THE GREATEST
THREAT FOR STORMS IN THE CHICAGO METRO TO BE FROM 6 PM TO 8 PM
THIS EVENING. INSTABILITY (CAPE OF NEAR 1000 J/KG) AND SHEAR
(0-6 KM BULK SHEAR NEAR 30 KTS) WILL PROVIDE THE RISK FOR SOME
SEVERE STORMS THROUGH THIS EVENING. THE SPC CURRENTLY HAS MUCH
OF LOT AREA IN A MARGINAL RISK FOR TONIGHT (EXCEPT THE SE).
SHOWERS AND ISOLATED STORMS WILL BE POSSIBLE OFF AND ON THROUGH
THE NIGHT ACROSS NORTHERN IL, WITH THE BEST CHANCE FOR A SECOND
ROUND FROM 3 AM TO 7 AM.
FOR WEDNESDAY, SHOWERS AND STORMS WILL LINGER IN THE VICINITY OF
A BOUNDARY NEAR THE IL/WI BORDER. EXPECT ACTIVITY TO BE MOSTLY
IN WI, AND GENERALLY, SEVERE STORMS ARE NOT EXPECTED TOMORROW.
HOWEVER, SOME MODELS HAVE CAPES NEAR 1000 J/KG AND DEEP SHEAR AT
25-30 KTS, SO IT'S NOT OUT OF THE QUESTION. CURRENTLY, NORTHERN
IL IS NOT OUTLOOKED FOR SEVERE WEATHER BY THE SPC. HIGHS
TOMORROW SHOULD BE IN THE MID TO UPPER 70S INLAND.
KNUTSVIG
WEDNESDAY NIGHT THROUGH TUESDAY:
WARM TEMPS WILL CONTINUE THROUGH THE WEEK WITH THE NEXT
WEATHER-MAKER COMING ON FRIDAY. SHOWERS AND ISOLATED STORMS ARE
GENERALLY EXPECTED, WITH SEVERE STORMS NOT EXPECTED CURRENTLY.
AFTER A RETURN TO COOLER TEMPERATURES OVER THE WEEKEND, EXPECT A
CHANCE FOR SEVERE STORMS POSSIBLY AS EARLY AS MONDAY.
KNUTSVIG
AVIATION /18Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 107 PM CDT TUE APR 22 2025
FORECAST CONCERNS FOR THE TERMINALS...
- PERIODS OF SCATTERED SHOWERS AND THUNDERSTORMS FROM LATE THIS
AFTERNOON THROUGH EARLY WEDNESDAY MORNING.
- BREEZY SOUTHWEST WINDS THIS AFTERNOON GUSTING 20-25 KT.
SHOWER/THUNDERSTORM ACTIVITY OVER SOUTHEAST WI/FAR NORTHEAST IL
IS ANTICIPATED TO MOVE OFF TO THE EAST, WITH A LULL IN STORM
ACTIVITY ANTICIPATED FOR MUCH OF THE EARLY TO MID AFTERNOON.
SCATTERED SHOWERS AND STORMS AHEAD OF A SUBTLE WAVE MOVING
ACROSS IA ARE PROJECTED TO ARRIVE IN NORTHEASTERN IL/FAR
NORTHWEST IN LATER THIS AFTERNOON. CONFIDENCE IN COVERAGE AND
PLACEMENT OF LIGHTNING STRIKES IS MODEST, BUT WE SHOULD SEE AN
INCREASE IN SHOWER DEVELOPMENT IN THE 23Z-01Z TIME FRAME.
CONFIDENCE IS LOW IN EXACT PLACEMENT OF A WEST-EAST BOUNDARY
DURING THE OVERNIGHT AND EARLY MORNING HOURS WHICH IS
ANTICIPATED TO ACT AS A FOCUS FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. IN ADDITION, SOME SPREAD IN TIMING OF STORM
DEVELOPMENT EXISTS AS WELL. WE OPTED FOR A PROB30 GROUP COVERING
THE MOST LIKELY EARLY MORNING TIME FRAME FOR NOW, BUT SOME
ADJUSTMENT IN THESE TIMES MAY OCCUR.
WINDS ARE ANTICIPATED TO SHIFT TO A MORE SOUTH-SOUTHWESTERLY
DIRECTION THROUGH 19Z, WITH SOME GUSTS UP TO 25 KT OR SO THROUGH
THE AFTERNOON. LOOK FOR SOUTHWESTERLY WINDS OF 10 KT OR LESS
THIS EVENING AND OVERNIGHT, BECOMING SOUTH-SOUTHEAST IN THE
MORNING WITH GUSTY AND ERRATIC WINDS A POSSIBILITY NEAR
THUNDERSTORMS.
NWS CENTRAL IL
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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