888
FXUS63 KIWX 071043
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
643 AM EDT THU MAY 7 2026
KEY MESSAGES
- FROST ADVISORY EARLY TODAY FAR SOUTHERN LOWER MICHIGAN.
- SCATTERED TO NUMEROUS SHOWERS AT TIMES THROUGH SUNDAY.
- A GRADUAL WARMING TREND THE REST OF THE WEEK WITH HIGHS AROUND
70 BY SATURDAY.
DISCUSSION
ISSUED AT 345 AM EDT THU MAY 7 2026
CHILLY TEMPERATURES WERE OVER THE REGION EARLY THIS MORNING
WHERE PATCHY TO AREAS OF FROST ARE EXPECTED. A FROST ADVISORY
REMAINS IN EFFECT OVER ALL OF FAR SOUTHWEST LOWER MICHIGAN
WHERE SOME CLOUDS OVER MOST AREAS WERE STILL HOLDING
TEMPERATURES ABOVE 40 DEGREES AS OF 3 AM EDT.
A LARGE UPPER LOW WAS OVER SOUTHERN HUDSON BAY. 500 MB HEIGHT
ANOMALIES WERE IN THE VICINITY OF NEGATIVE 400 METERS PER GFS.
IMPULSES ASSOCIATED WITH THIS SYSTEM WERE HELPING TO GENERATE
LIGHT SHOWERS. A STRONG IMPULSE WILL TOP THE UPPER LEVEL RIDGE
EARLY NEXT WEEK AND BRING SHOWERS AND A SLIGHT CHANCE FOR
THUNDERSTORMS FROM TUESDAY INTO WEDNESDAY.
THE ATMOSPHERIC ENVIRONMENT WILL HAVE VERY LIMITED INSTABILITY
ALL OF THE WAY THROUGH THE MIDDLE OF NEXT WEEK WITH MAXIMUM CAPE
VALUES GENERALLY LESS THEN 400 J/KG. LOW-TOPPED CONVECTION IS
LIKELY, BUT ELS WILL BE QUITE LOW - GENERALLY UNDER 15K. NO
SEVERE THUNDERSTORMS ARE EXPECTED.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 640 AM EDT THU MAY 7 2026
PRIMARILY VFR CONDITIONS EXPECTED THROUGH THIS FORECAST VALID
PERIOD, WITH POSSIBLE EXCEPTION BEING ANY HEAVIER SHOWER
ACTIVITY LATER THIS AFTERNOON/EVENING.
AN UPPER LEVEL SHORT WAVE ACROSS NORTHEAST IOWA WILL DIG ACROSS
THE SOUTHERN GREAT LAKES REGION THROUGH MID AFTERNOON, BUT WILL
HAVE MEAGER MOISTURE TO WORK WITH. AS THIS SHORT WAVE BEGINS TO
PULL OFF TO THE EAST, A ZONE OF STRONGER ISENTROPIC ASCENT AND
MOISTURE ADVECTION WILL TRY TO SHIFT INTO NORTHERN INDIANA WITH
WARM-FRONT LIKE FEATURE ACROSS NORTHERN ILLINOIS. DRY SUBCLOUD
LAYERS SHOULD LIMIT INSTABILITY BUT GIVEN STRENGTH OF LOW LEVEL
FRONTOGENESIS FORCING AND POTENTIAL OF SOME VERY WEAK SFC-BASED
INSTABILITY LATE AFTERNOON/EARLY EVENING, WOULD EXPECT SCATTERED
SHOWER DEVELOPMENT IN POSSIBLY A NARROW CORRIDOR FROM NE IL
INTO NORTHERN IN. BOTH TERMINALS APPEAR VULNERABLE TO SOME
WINDOW FOR SHOWER POTENTIAL, WITH THE WINDOW LOOKING TO BE OF
SHORTER DURATION AT KSBN LATE AFTERNOON/EARLY EVENING BEFORE
STRONGER 925-850MB FGEN FORCING SLIPS TO THE SOUTH. CANNOT
COMPLETELY DISCOUNT SOME ISOLATED THUNDER GIVEN STRENGTH OF
FRONTAL FORCING AND WEAK INSTABILITY, BUT CONFIDENCE IN THUNDER
AT TERMINALS IS VERY LOW. POTENTIAL OF SHOWERS SHOULD DIMINISH
AT KFWA CLOSER TO MIDNIGHT TONIGHT AS FORCING MECHANISMS DROP
SOUTH OF THE TERMINAL. OTHERWISE, BOUNDARY LAYER AVERAGED WINDS
THIS AFTERNOON OF AROUND 15 KNOTS COULD PROMOTE SOME GUSTS INTO
THE 15 TO 20 KNOT RANGE AT BOTH KSBN AND KFWA DURING PEAK
MIXING HOURS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ078>081-177-
277.
MARINE...NONE.
DISCUSSION...SKIPPER
AVIATION...MARSILI
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