946
FXUS63 KIWX 041913
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
313 PM EDT MON MAY 4 2026
KEY MESSAGES
- THERE IS A MARGINAL TO SLIGHT RISK FOR SEVERE STORMS THIS
EVENING AND TONIGHT (5PM TO 1AM EDT). EXPECT DAMAGING WINDS TO
60 MPH, HAIL UP TO AROUND 1 INCH IN DIAMETER WITH SEVERE
STORMS. AN ISOLATED TORNADO CANNOT BE RULED OUT. HEAVY RAIN
AND FLOODING IS POSSIBLE INTO THE OVERNIGHT HOURS.
- MORE WIDESPREAD RAIN IS EXPECTED TUESDAY, WITH CHANCES FOR
NON- SEVERE THUNDERSTORMS IN THE AFTERNOON. HIGHS WILL BE IN
THE 50S AND 60S, WARMEST ALONG AND SOUTH OF US 24.
- CHANCES FOR RAIN WEDNESDAY AND FRIDAY, WITH ISOLATED
THUNDERSTORMS POSSIBLE ON FRIDAY AFTERNOON. HIGHS WILL BE IN
THE 50S, LOW 60S. LOWS WILL BE IN THE MID TO UPPER 30S
WEDNESDAY NIGHT, AND THE 40S THURSDAY AND FRIDAY NIGHT.
DISCUSSION
ISSUED AT 311 PM EDT MON MAY 4 2026
THIS EVENING-TONIGHT'S MARGINAL RISK FOR SEVERE WEATHER WAS UPGRADED
TO A SLIGHT RISK FOR PORTIONS OF THE AREA. CONFIDENCE IN SEVERE
WEATHER OCCURRING IS MEDIUM. THERE ARE SOME UNCERTAINTIES WITH
REGARDS TO THE START TIME OF THE EVENT. MUCH OF THE GUIDANCE
INITIATES STORMS CLOSEST TO 7-8 PM EDT, BUT THERE ARE STILL SEVERAL
MODELS THAT BEGIN CLOSER TO 5-6 PM EDT. A LOT WILL DEPEND ON THE
AVAILABLE MOISTURE-WHICH COULD LIMIT DEVELOPMENT INITIALLY (WELL
MIXED BOUNDARY LAYER FROM FULL SUN EARLIER TODAY). A DECENT CU FIELD
HAS DEVELOPED FOR AREAS WEST OR JUST ALONG I 69 AS OF THIS WRITING.
DEWPOINTS ARE IN THE MID-UPPER 40S AND LOW 50S, DRIEST FURTHER NORTH
IN MI/NW OHIO. THIS IS LOWER THAN WHAT THE EARLIER TIMED MODELS
SUGGEST (NAM/RAP)--VALUES ARE CLOSER IN LINE TO THE HRRR. IF THE
HRRR IS RIGHT, DEVELOPMENT MAY BE CLOSER TO 8 PM EDT WHEN THE BETTER
MOISTURE ARRIVES (STILL ONLY MID 50S) WITH STRENGTHENING OF THE LLJ.
MAIN FOCUS FOR CONVECTION WILL BE A MID-LEVEL WAVE RIDING UP FROM
THE SOUTHWEST THIS EVENING (AFOREMENTIONED "WARM-FRONT-LIKE" FEATURE
IN PREV. AFD)-THEN THE COLD FRONT THAT DROPS FROM NW TO SE THROUGH
THE OVERNIGHT. THE MAIN THREAT WITH ANY SEVERE STORMS WOULD BE
DAMAGING WIND GUSTS GIVEN INVERTED-V TYPE SOUNDINGS. LARGE HAIL IS
ALSO POSSIBLE WITH 25-35 KNOTS OF 0-6KM SHEAR AND MID LEVEL LAPSE
RATES AROUND 7C/KM (COULD BE SLIGHTLY HIGHER FURTHER SOUTH OF US 30
THIS EVENING PER THE NAM). HEAVY RAIN AND PONDING OF WATER ON THE
ROADS IS A THREAT IN ANY THUNDERSTORMS, HOWEVER OVERNIGHT THERE
COULD BE SOME MINOR FLOODING IN AREAS THAT RECEIVE REPEATED STORM
ACTIVITY (FROM BOTH THE EARLIER WAVE AHEAD OF THE COLD FRONT AND
THEN THE COLD FRONT ITSELF).
SPC DID ADD A 2 PERCENT TORNADO RISK WITH THE INCREASED LOW LEVEL
SHEAR (DECENT HODOGRAPHS)...HOWEVER IT'S CONDITIONAL ON MOISTURE
PROFILES AS WELL (WHICH IS OUR GREATEST UNCERTAINTY). IF WE GET THE
DEEPER MOISTURE WE COULD SEE LCL'S IN THE 500-1000 M RANGE (MORE
FAVORABLE FOR TOR RISK). PER THEIR DISCUSSION, THEY WILL RE-
EVALUATE THE MOISTURE QUALITY FOR THE TOR RISK.
OTHERWISE, COLD FRONT CONTINUES EASTWARD THROUGH TUESDAY, STALLING
NEAR US 24, WITH SURFACE LOW RIDING UP ALONG/SOUTHEAST OF IT THROUGH
THE AFTERNOON. RAIN WILL BE FAIRLY WIDESPREAD (ESPECIALLY ALONG THIS
CORRIDOR), WITH CHANCES FOR A FEW THUNDERSTORMS (NON-SEVERE). AS THE
SURFACE LOW DRIFTS E-SE THROUGH WEDNESDAY, EXPECT DWINDLING CHANCES.
DRY CONDITIONS THU, THEN CHANCES FOR RAIN AND A FEW STORMS RETURN
FRI INTO THE WEEKEND. HIGHS WED-FRI WILL BE IN THE 50S, LOW 60S.
OVERNIGHT LOWS WILL BE IN THE MID-UPPER 30S WED NIGHT (COLDEST
ALONG/NORTH OF I 80-90) WITH LIGHT WINDS-SO THERE COULD BE SOME
FROST POTENTIAL. WARMER SAT-SUN WITH HIGHS IN THE MID-UPPER 60S, LOW
70S.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 142 PM EDT MON MAY 4 2026
A WARM FRONTAL FEATURE MOVES NORTHWARD FROM CENTRAL IN/IL AREA THIS
AFTERNOON INTO THE EVENING AHEAD OF A COLD FRONT SLIDING SOUTHEAST
FROM THE WESTERN GREAT LAKES. THESE FEATURES BRING CHANCES FOR
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING WITH
DAMAGING WIND, HAIL, A LOW CHANCE FOR A TORNADO AS THE MAIN THREATS.
IN ANY THUNDERSTORM, HEAVY RAIN CAN LEAD TO THE VISIBILITY AND
CEILINGS DROPPING DOWN INTO MVFR CONDITIONS. THE TENDENCY FOR THESE
STORMS WILL BE TO GO FROM A SEVERE THREAT TO A HEAVY RAIN THREAT AS
WE MOVE INTO THE OVERNIGHT PERIOD.
WINDS ARE EXPECTED TO BE SOUTH OF THE SOUTHWEST THIS AFTERNOON INTO
TONIGHT BEFORE BECOMING MORE NORTHWESTERLY. GUSTS TODAY TO 30 KTS
CALM DOWN TONIGHT AND WEAKER WINDS OCCUR ON TUESDAY WITH THE FRONT
SLIDING THROUGH. ADDITIONALLY, SOME LLWS WILL BE POSSIBLE
TONIGHT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ043-
046.
DISCUSSION...MCD
AVIATION...ROLLER
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