307
FXUS63 KIWX 251937
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
337 PM EDT SAT APR 25 2026
KEY MESSAGES
- DRY AND SEASONABLE THROUGH THE WEEKEND WITH TEMPERATURES IN THE
MID 60S TO NEAR 70 DEGREES.
- CONFIDENCE IS INCREASING THAT THERE COULD BE SEVERE WEATHER
LATE MONDAY AFTERNOON THROUGH MONDAY NIGHT. DAMAGING WINDS
AND EMBEDDED TORNADOES WILL BE THE MAIN THREATS. THERE IS ALSO
POTENTIAL FOR HEAVY RAIN AND FLOODING AFTER SUNSET ON MONDAY.
- COOLER AIR IS AHEAD NEXT WEEK TO BEGIN MAY! HIGHS ONLY IN THE
50S AND 60S AND LOWS AS COLD AS THE MID 30S WILL BE POSSIBLE
BY THE MIDDLE TO END OF NEXT WEEK. NEAR FREEZING TEMPERATURES
AT NIGHT MAY DAMAGE EARLY SEASON CROPS AND PLANTS!
DISCUSSION
ISSUED AT 336 PM EDT SAT APR 25 2026
TODAY IS ABOUT AS QUIET OF A DAY AS YOU CAN GET ACROSS THE UPPER
GREAT LAKES IN APRIL WITH MOSTLY SUNNY SKIES, LIGHT NORTHERLY WINDS,
AND TEMPERATURES IN THE 60S THIS AFTERNOON. THANKS TO AN UPPER LEVEL
RIDGE, ANOTHER PLEASANT DAY IS AHEAD SUNDAY WITH NEARLY
IDENTICAL CONDITIONS (ALBEIT A BIT MORE CLOUD COVER, ESPECIALLY
IN THE MORNING). SEASONABLE TEMPERATURES PERSIST WITH CAA FROM
PREVAILING NORTHERLY WINDS.
CONFIDENCE IS INCREASING THAT THERE COULD BE SEVERE WEATHER LATE
MONDAY AFTERNOON THROUGH MONDAY NIGHT. A SERIES OF STRONG 500 MB
SHORTWAVES WILL EJECT OUT OF THE COLORADO ROCKIES LATE SUNDAY, WITH
A LOW PRESSURE SYSTEM DEVELOPING ACROSS THE CENTRAL PLAINS AND
DEEPENING AS IT LIFTS INTO THE UPPER MIDWEST BY MONDAY EVENING. A
WARM FRONT IS EXPECTED TO LIFT NORTHWARD THROUGH OUR AREA DURING THE
DAY MONDAY, WITH BREEZY SOUTHWESTERLY WINDS AND WAA BOOSTING HIGHS
TO THE UPPER 70S TO NEAR 80 DEGREES. MOISTURE RETURN FROM THE GULF
WILL ALSO BOOST DEWPOINTS INTO THE LOW TO MID 60S MONDAY AFTERNOON.
CLUSTERS OF STORMS OR A MORE ORGANIZED QLCS SHOULD DEVELOP AND MOVE
THROUGH IOWA, MISSOURI, AND ILLINOIS DURING THE AFTERNOON ON MONDAY.
THE CURRENT THINKING IS THAT THIS CONVECTION WILL SUSTAIN ITSELF
INTO OUR FORECAST AREA BY MONDAY EVENING INTO MONDAY NIGHT, ALTHOUGH
UNCERTAINTY REMAINS ON JUST HOW FAR EAST IT WILL BE ABLE TO MAINTAIN
SEVERE STATUS. AN ENHANCED RISK FOR SEVERE WEATHER DOES CLIP OUR FAR
SOUTHWEST (WHITE COUNTY, IN), WITH A SLIGHT RISK ACROSS MUCH OF
NORTHERN INDIANA. MODEL RUNS TODAY HAVE SLIGHTLY SPED UP THE TIMING
OF THE WARM FRONT DURING THE DAY MONDAY, WHICH WOULD MEAN OUR AREA
ENDS UP IN A MORE FAVORABLE ENVIRONMENT FOR SEVERE WEATHER; GUIDANCE
FROM THE NAM AND GFS SHOW CONVECTION GETTING INTO FAR WESTERN
INDIANA BETWEEN 21-00Z WHILE THE ECMWF CONTINUES TO DELAY IT UNTIL
06Z. WE WILL LIKELY BE ABLE TO DISCERN EXACT TIMING IN THE NEXT 24
HOURS OR SO AS MODELS HONE IN ON A CONSENSUS, HOWEVER, I DO THINK
THAT THE BEST WINDOW FOR SEVERE WEATHER WILL BE FROM 6 PM EDT MONDAY
TO 2 AM EDT TUESDAY. THE BEST POTENTIAL FOR SEVERE WEATHER WILL
LIKELY BE WEST OF US 31. THIS MAY END UP BEING A HIGH SHEAR, LOW
CAPE SETUP ON MONDAY AS INSTABILITY IS EXPECTED TO DIMINISH AFTER
DARK. DESPITE A LOSS OF INSTABILITY AFTER SUNSET (ONLY 500-1000 J/KG
MUCAPE), THERE DOES APPEAR TO BE A DECENT SETUP GIVEN ~40 KTS OF
BULK SHEAR AND ~150 M2/S2 OF 0-1 KM SRH. ALL HAZARDS WILL BE
POSSIBLE IF SEVERE WEATHER OCCURS MONDAY EVENING INTO MONDAY NIGHT,
INCLUDING DAMAGING WINDS, LARGE HAIL, AND TORNADOES. THERE IS ALSO
POTENTIAL FOR HEAVY RAIN AND EFFICIENT RAINFALL RATES OVER 2"/HR.
WITH PWATS NEAR 1.50" (WHICH IS AROUND THE 99TH PERCENTILE
CLIMATOLOGY FOR APRIL 27TH), AMPLE LOW LEVEL MOISTURE, AND FORECAST
SOUNDING DEPICTING A DEEP, WARM CLOUD LAYER, FLOODING WILL BE
POSSIBLE LATE IN THE DAY ON MONDAY. TOTAL QPF ACROSS OUR FORECAST
AREA IS EXPECTED TO BE BETWEEN 0.50" TO 1.50" BY EARLY TUESDAY
MORNING.
AN UNSEASONABLY COOL AIRMASS WILL FILTER INTO THE GREAT LAKES REGION
BY THE MIDDLE TO END OF NEXT WEEK AS AN UPPER LEVEL LOW DEVELOPS
OVER THE NORTHEAST. WITH DOMINANT NORTHERLY FLOW, THE CLIMATE
PREDICTION CENTER HAS 60-70% PROBABILITIES FOR COOLER THAN
NORMAL TEMPERATURES BY THE END OF APRIL INTO EARLY MAY. HIGHS
ONLY IN THE 50S AND 60S AND LOWS AS COLD AS THE MID 30S WILL BE
POSSIBLE BY THE MIDDLE TO END OF NEXT WEEK. THE GROWING SEASON
HAS ALREADY BEGUN FOR OUR FORECAST AREA AS OF MID-APRIL. NEAR
FREEZING TEMPERATURES AT NIGHT MAY DAMAGE EARLY SEASON CROPS AND
PLANTS!
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 123 PM EDT SAT APR 25 2026
WITH RIDGING REMAINING ACROSS THE AREA POST-COLD FRONT FROM
YESTERDAY, THE AREA IS SET TO BE AFFECTED BY FORMING LOW LEVEL
INVERSIONS OVERNIGHT. GIVEN LOW LEVEL MOISTURE FROM RECENT RAIN,
AND THE COMBINATION OF TIMES OF FOG AND STRATUS ACROSS THE AREA
LAST NIGHT, WE'LL HAVE TO WATCH OUT FOR STRATUS/FOG FORMATION
AGAIN TONIGHT. WITH HIGH PRESSURE MOVING SOUTHEASTWARD, NORTH OF
THE AREA, EAST WINDS TAKE HOLD LATE TONIGHT. THIS WOULD TEND TO
INDICATE THAT THE AREA TO WATCH WILL BE IN THE I-69 CORRIDOR TO
START. AT THIS POINT, AVIATION GUIDANCE IS JUST TAKING MVFR CIGS
TO SBN SO CONFIDENCE IS LOW ON WHETHER OR NOT THEY HAVE SOME
TIME IN MVFR CIGS. NAM BUFKIT SOUNDINGS APPEAR TO KEEP FOG OUT
OF BOTH AREAS WITH FWA NEVER DECOUPLING. THIS WOULD MAKE STRATUS
MORE POSSIBLE AND THAT SEEMS TO BE WHAT AVIATION GUIDANCE
INDICATES. THERE'S MORE CONFIDENCE IN STATUS AT FWA AND THINK
MVFR IS A GOOD PLACE TO START WITH THIS ISSUANCE. IT IS POSSIBLE
WE END UP WITH FUEL ALTERNATE AND THAT THE TIME FRAME OF THESE
MVFR CIGS IS SLIGHTLY ADJUSTED SO CONFIDENCE IN THIS IS
RELATIVELY LOW.
AS MENTIONED BEFORE, THE EASTWARD MOVEMENT OF HIGH PRESSURE TO OUR
NORTH ALLOWS WINDS TO VEER FROM NORTHERLY TO EASTERLY OVERNIGHT.
INITIAL 10 KT SUSTAINED WINDS LIGHTEN UP OVERNIGHT. WHILE 10 KT
SUSTAINED WINDS ARE POSSIBLE ON SUNDAY, GUSTS STRUGGLE TO REACH 25
KTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...SKIPPER
AVIATION...JOHNSON
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