508
FXUS63 KLOT 222347
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
647 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 /00Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 647 PM CDT TUE APR 22 2025
KEY AVIATION MESSAGES FOR THE CURRENT TAF PERIOD:
- PERIODS OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
WEDNESDAY MORNING
SHOWERS AND THUNDERSTORMS ARE GRADUALLY STARTING TO MOVE IN
FROM THE WEST ALONG A WEST-TO-EAST FRONTAL BOUNDARY THAT BECOMES
QUASI-STATIONARY THROUGH THE TAF PERIOD. HI-RES GUIDANCE
CONTINUES TO DEPICT PERIODS OF SHOWERS AND STORMS THROUGH THE
TAF WINDOW, BUT THAT ALSO MEANS THAT THERE WILL BE BREAKS IN
PRECIP AS WELL WHICH LOWERS CONFIDENCE IN THE EXACT TIMING AT
ANY GIVEN SHOWER/STORM. THE WINDOW FOR THUNDER WAS KEPT AS A
PROB30 IN THE TAFS FOR THE CURRENT EXPECTATIONS FOR STORMS THIS
EVENING AS WELL AS AGAIN TOMORROW MORNING WITH ANY ADJUSTMENTS
TO TIMING HAPPENING TACTICALLY. SHOWERS MAY LINGER INTO THE
AFTERNOON, BUT GENERALLY BE ON A DOWNWARD TREND AS THE AXIS OF
BETTER MOISTURE SHIFTS NORTH.
WINDS REMAIN SOUTHWEST THROUGH THE NIGHT AS GUSTS AROUND 20
KNOTS SLOWLY DIMINISH AFTER SUNSET. WINDS WILL REMAIN AROUND 10
KNOTS THROUGH THE DAY ON WEDNESDAY. THEY ARE EXPECTED TO BE
MOSTLY OUT OF THE SOUTH-SOUTHEAST, THOUGH THERE COULD BE A BRIEF
WINDOW WHERE THEY FLIP TO THE SOUTHWEST IN THE AFTERNOON.
DK/NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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