377
FXUS63 KIWX 120535
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
135 AM EDT SUN APR 12 2026
KEY MESSAGES
- 20% TO 40% CHANCE OF SHOWERS TONIGHT ALONG THE SOUTHERN
MICHIGAN STATE LINE.
- VERY WARM AND BREEZY ON SUNDAY. SOUTHWESTERLY WIND GUSTS OF 30
MPH AND HIGHS WELL INTO THE 70S.
- INCREASING CHANCE OF RAIN SUNDAY EVENING (40% CHANCE) THROUGH
MONDAY MORNING (60% CHANCE) BUT REMAINING WARM.
DISCUSSION
ISSUED AT 149 PM EDT SAT APR 11 2026
HIGH PRESSURE TODAY GIVES WAY TO AN INCOMING DISTURBANCE CURRENTLY
OVER NORTHERN MISSOURI. THIS FEATURE LIFTS NORTHEAST TONIGHT ATOP A
STRONG SOUTHEAST US UPPER-LEVEL RIDGE RESULTING IN A 20% TO 40%
CHANCE OF SHOWERS TONIGHT ALONG THE SOUTHERN MI BORDER. A SPECIAL
SOUNDING FROM THE STUDENTS AT VALPARAISO UNIVERSITY LATE THIS
MORNING REVEALED A STRONG SUBSIDENCE INVERSION AND PLENTY OF DRY
AIR; PWAT OF 0.45". UPSTREAM DEW POINTS IN THE MID-40S ARE BETTER
THAN OUR LOCAL DEW POINT THIS HOUR, THUS, IMPROVED MOISTURE
ADVECTION AND FORCING WILL BE NEEDED PRIOR TO RAIN REACHING THE
GROUND.
WARM AND BREEZY SUNDAY, WITH SOUTHWESTERLY WIND GUSTS OF 30
MPH, AS THE PRESSURE GRADIENT TIGHTENS AGAINST SURFACE HIGH
PRESSURE OFF THE ATLANTIC COAST. RAIN CHANCES INCREASE IN THE
EVENING FROM WEST TO EAST AS ANOTHER SHORTWAVE MOVES THROUGH.
THIS ACTIVITY, LINGERING INTO MONDAY MORNING, DOES NOT APPEAR TO
POSE A SEVERE WEATHER RISK OWING TO AN ABSENCE OF INSTABILITY.
INSTABILITY IMPROVES MONDAY NIGHT, WITH THE BEST COLOCATION OF
SEVERE WEATHER INGREDIENTS NOTED OVER SOUTHEAST WI. UPSTREAM
ACTIVITY FOR ANY SEVERE STORMS THAT DRIFT EAST.
TUESDAY EVENING CONTINUES TO BE THE PRIMARY PERIOD OF INTEREST FOR
SEVERE STORMS. A SHORTWAVE TROUGH OVER THE CENTRAL PLAINS AND
ASSOCIATED SURFACE LOW DEEPEN WHILE AN ELONGATED FRONT DRAPES
ACROSS OUR AREA. INSTABILITY IN EXCESS OF 1,500 J/KG LOCALLY ALONG
WITH 45 KNOTS OF SHEAR ARE FAVORABLE INDICATORS THAT ANY STORMS
THAT FIRE OVER ILLINOIS CAN TRACK EAST INTO OUR AREA. BOUNDARY-
PARALLEL FLOW RAISES THE RISK OF TRAINING THUNDERSTORMS PRODUCING
HEAVY RAINFALL AS WELL.
WET WEATHER LINGERS INTO WEDNESDAY AND THURSDAY UNTIL THE PARENT
TROUGH FINALLY SHIFTS EAST. A STRONG UPPER-LEVEL RIDGE PERSISTS OVER
THE SOUTHEAST US KEEPING TEMPERATURES VERY WARM.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 129 AM EDT SUN APR 12 2026
LOW LEVEL WARM MOIST ADVECTION IS AIDING THE DEVELOPMENT OF SOME
SCATTERED SHOWERS ACROSS LOWER MICHIGAN EARLY THIS MORNING. LOW
LEVEL FLOW TRAJECTORIES ARE NOT IDEAL ACROSS NORTHERN INDIANA
TODAY FOR SIGNIFICANT MOISTURE TRANSPORT HOWEVER, AS AXIS OF
RICHER LEVEL MOISTURE SHOULD BE FAVORED JUST BACK TO THE WEST
ACROSS THE MID MS RIVER VALLEY. AN UPPER LEVEL SHORT WAVE ACROSS
THE SOUTHERN PLAINS EARLY THIS MORNING WILL EJECT NORTHEAST AND
REACH THE WESTERN GREAT LAKES TONIGHT. WITH A MORE FAVORABLE
SHORT WAVE TRACK AND WEAK INSTABILITY AXIS SETTING UP ACROSS NW
IN INTO S LOWER MI, CANNOT COMPLETELY RULE OUT ISOLATED SHOWER
OR STORM IN KSBN VICINITY THIS AFTERNOON/EARLY EVENING, BUT
BETTER CHANCES ARE EXPECTED LATER THIS EVENING AS PRIMARY LOW
LEVEL MOISTURE AXIS SHIFTS ACROSS THE SOUTHERN GREAT LAKES. THIS
PRECIP POTENTIAL WILL BE ADDRESSED IN GREATER DETAIL WITH THE
12Z TAFS. OTHERWISE TODAY, IT WILL BECOME WINDY IN THE
DEVELOPING WARM SECTOR ACROSS NORTHERN INDIANA WITH SOUTH-
SOUTHWEST GUSTS TO 30 KNOTS AT TIMES. A LOW LEVEL JET SHIFTING
EAST ACROSS THE AREA TONIGHT WILL LIKELY KEEP THESE WINDY
CONDITIONS IN PLACE TONIGHT. IN ADDITION, A BRIEF PERIOD OF LOW
LEVEL WIND SHEAR HAS BEEN MAINTAINED THIS MORNING BEFORE
STRONGER LOW LEVEL WINDS BEGIN TO MIX TO THE SURFACE MID
MORNING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 8 AM EDT MONDAY
FOR LMZ043-046.
DISCUSSION...BROWN
AVIATION...MARSILI
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