344
FXUS63 KIWX 261026
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
626 AM EDT THU MAR 26 2026
KEY MESSAGES
- VERY WARM TODAY WITH HIGHS IN THE 70S AND 80S. A 50-60% CHANCE
FOR 80 DEGREE HIGHS EXISTS MAINLY SOUTH OF US-24. COOLER AIR
IS ACROSS THE AREA BETWEEN TONIGHT AND SATURDAY NIGHT.
- THERE IS A 90% CHANCE FOR SHOWERS AND STORMS THIS EVENING.
STORMS COULD BE SEVERE WITH DAMAGING WIND GUSTS, LARGE HAIL,
HEAVY RAIN AND TORNADOES. THE GREATEST SEVERE WEATHER THREAT
IS BETWEEN 5PM AND 12AM ET. DRIER THROUGH THE WEEKEND.
- CHANCES FOR RAIN RETURN MIDWEEK INTO THE END OF NEXT WEEK.
DISCUSSION
ISSUED AT 237 AM EDT THU MAR 26 2026
BEHIND THIS MORNING'S SYSTEM, THE MAIN QUESTION WILL BE ABOUT IF
WE CAN GENERATE ANY INSTABILITY AHEAD OF THE EVENING
THUNDERSTORM CHANCE. A FRONTAL BOUNDARY IS ALREADY ATTEMPTING TO
SAUNTER SOUTHWARD AROUND 21Z OR SO AND SO STRATUS WILL BE HOT ON
ANY THUNDERSTORMS TAIL SHOULD THEY FORM ALONG OR JUST AHEAD OF
THE COLD FRONT. SOUNDINGS INDICATE THERE IS A CAP, WHICH APPEARS
TO HOLD FOR THE MORNING INTO THE AFTERNOON AND PROBABLY HOLDS
ON UNTIL LARGE SCALE ASCENT CAN GET HERE. THE HRRR SEEMS TO
SPROUT AREAS OF SHOWERS/STORMS AS AREAS OF A THERMAL GRADIENT
PUSH THROUGH, BUT THE BETTER LARGE SCALE ASCENT WAITS TO ARRIVE
AROUND 21Z. WE'LL ALSO HAVE TO LOOK FOR DIFFERENTIAL HEATING
BOUNDARIES THAT COULD BE THE FOCUS FOR ANY PRE-FRONTAL
CONVECTION WHICH COULD HAVE A MORE DISCRETE STORM MODE.
STRONG EFFECTIVE SHEAR GREATER THAN 30 KTS PAIRS WITH 1 TO 2
THOUSAND J/KG OF CAPE TO CREATE AN ENVIRONMENT CONDUCIVE TO SEVERE
THUNDERSTORMS. THE EML RE-ESTABLISHES ITSELF ACROSS THE AREA DURING
THE MIDDAY AND AFTERNOON HOURS, ESPECIALLY SOUTH OF US-30 AND WEST
OF I-69. INITIAL SHEAR ORIENTATION IS BOUNDARY-PERPENDICULAR
ALLOWING CELLS TO HAVE THE POTENTIAL TO BE DISCRETE. GIVEN HELICITY
VALUES OVER 200 UNITS, INITIAL STORMS WILL BE ABLE TO PRODUCE BOTH A
TORNADO AND, WITH THE OTHER SEVERE PARAMETERS, LARGE HAIL. THERE IS
SOME UNCERTAINTY HOW LONG SHEAR REMAINS BOUNDARY-PERPENDICULAR SO AS
THERE MAY BE A TENDENCY FOR STORMS TO CONGEAL AS SHEAR BECOMES
BOUNDARY-PARALLEL OVERTIME, THERE STILL COULD BE ENOUGH TURNING TO
ALLOW EMBEDDED VORTICIES WITHIN THE LINE FOR MORE OF A QLCS LOOK.
THIS LINE CONTINUES SHIFTING SOUTHEASTWARD AND AS DEW POINTS REACH
60+ DEGREES AND 850 MB DEW POINTS SURPASS 10C, HEAVY RAIN WILL BE
POSSIBLE. TRAINING OF STORMS WILL BE POSSIBLE, BUT IT DOESN'T LOOK
MBE VECTORS WILL ALLOW BACKBUILDING SO FLOODING MAY BE LESS OF A
FACTOR WITH LOWER STORM COVERAGE AND WITH THE LINE MOVING SOUTHWARD
STEADILY. THE LINE LOOKS TO VACATE OUR AREA BY 3 TO 4Z, BUT WILL
LIKELY HAVE SOME STRATIFORM RAIN FOLLOWING ON ITS BACKSIDE. THERE
HAS BEEN SOME INDICATE, TOO, THAT COLD AIR COULD CATCH UP TO CREATE
FLURRIES, BUT THE INGREDIENTS AREN'T REALLY THERE FOR AN ANAFRONTAL
SETUP.
CLOUDS DISSIPATE FRIDAY AFTERNOON AS SURFACE HIGH PRESSURE PUSHES IN
BEHIND A STRONG VORT MAX, WHICH PUSHES THROUGH BEHIND THE DEPARTING
COLD FRONT. HIGHS FALL BACK TO THE 40S FOR FRIDAY AND SATURDAY WITH
30S FOR LOWS THURSDAY NIGHT AND SATURDAY NIGHT, 20S FOR LOWS FRIDAY
NIGHT.
THEN, FOR SUNDAY AND MONDAY, A TROUGH PUSHES IN ATOP THE RIDGE IN
THE WEST SUPPRESSING IT. AS A RESULT, A WARM FRONT DEVELOPS NORTH OF
THE AREA BY MONDAY. HIGHS REACH THE 70S FOR THE NEXT WORK WEEK AS
WARM ADVECTION RETURNS. STRONG GULF MOISTURE ADVECTION ENSUES AND
SKIES CLOUD UP. AS THE WARM FRONT SAGS BACK SOUTHWARD WITH A STRONG
HIGH PRESSURE SYSTEM MOVING INTO SOUTHERN CANADA, WAVES OF SHOWERS
AND THUNDERSTORMS WILL BECOME POSSIBLE. THE PLACEMENT OF THIS
BAROCLINIC ZONE WILL DECIDE WHERE STORMS FORM. IT COULD BE JUST
NORTH OF OUR AREA. AN ATTEMPT TO PUSH A COLD FRONT THROUGH THE AREA
IS MADE FOR THE END OF NEXT WEEK, BUT THAT COULD STALL AROUND OUR
AREA AND CAUSE TIMES OF RAIN AND ADDITIONAL STORMS.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 622 AM EDT THU MAR 26 2026
THE COUPLE AREAS OF CONCERN FOR THESE TAFS WILL BE THE THUNDERSTORMS
THAT GET UNDERWAY LATER THIS AFTERNOON AND EVENING AS WELL AS THE
STRATUS DECK THAT FORMS BEHIND THEM. AS A 700 MB SHORTWAVE
APPROACHES THE AREA FROM N IL AROUND 21Z, ENOUGH LARGE SCALE ASCENT
IS EXPECTED TO BE PRESENT TO BREAK THE CAP AND CAUSED THUNDERSTORMS
TO ERUPT ACROSS THE AREA UP UNTIL AROUND 3 OR 4Z. MODEL TRENDS HAVE
ADJUSTED SLIGHTLY SOUTHWARD AND QUICKER OVERNIGHT WITH THE STRONG
LINE OF CONVECTION AND ANY PRE-FRONTAL STORM INITIATION THAT OCCURS
AND SO THAT COULD PUSH IT OUT OF THE AREA QUICKER. THUNDERSTORMS ARE
EXPECTED TO HAVE THE POTENTIAL TO CREATE HEAVY RAIN AND SO VISBY
REDUCTIONS INTO IFR AND LIFR WILL BE VERY POSSIBLE. CIGS ARE
EXPECTED TO BE IN MVFR OR IFR AS THIS HAPPENS. ONCE THUNDERSTORMS
LEAVE EXPECT A MODERATION INTO MVFR EVEN BY LATER FRIDAY NIGHT/EARLY
FRIDAY MORNING.
ADDITIONALLY, GUSTY WINDS 25 TO 30 KTS WILL BE POSSIBLE THIS
AFTERNOON AS MIXING SLOWLY COMMENCES.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EDT FRIDAY FOR
LMZ043-046.
DISCUSSION...ROLLER
AVIATION...ROLLER
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