716
FXUS63 KIWX 251822
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
222 PM EDT WED MAR 25 2026
KEY MESSAGES
- VERY WARM ON THURSDAY WITH HIGHS IN THE 80S SOUTH OF US 24,
WITH MOST OTHER LOCATIONS SEEING HIGHS IN THE 70S. SHARPLY
COLDER THURSDAY NIGHT AND FRIDAY.
- THERE IS AN 80% TO 90% CHANCE FOR SHOWERS AND STORMS THURSDAY
EVENING. STORMS COULD BE SEVERE WITH DAMAGING WIND GUSTS,
LARGE HAIL, HEAVY RAIN AND TORNADOES. THE GREATEST SEVERE
WEATHER THREAT IS BETWEEN 5PM AND 11PM EDT.
DISCUSSION
ISSUED AT 212 PM EDT WED MAR 25 2026
PERSISTENT, LARGE UPPER-LEVEL RIDGING REMAINS IN PLACE OVER MUCH OF
THE SOUTHWEST AND SOUTH-CENTRAL US. ENERGETIC FLOW SPILLS ATOP THIS
RIDGE AND OVER THE GREAT LAKES. WITHIN THIS FLOW IS A SHARP UPPER-
LEVEL LOW THAT FLOATS THROUGH TONIGHT BRINGING A 30-60% CHANCE
OF SHOWERS (AND PERHAPS A RUMBLE OF THUNDER) TO AREAS PRIMARILY
SOUTH OF US 30. ABUNDANT LOW-LEVEL DRY AIR WILL CUT INTO
RAINFALL AMOUNTS WHILE MEAGER MUCAPE OF LESS THAN 500 J/KG
RAISES QUESTIONS ABOUT THE RISK OF THUNDER. WITH THE FREEZING
LAYER NEAR 10K FT, CANNOT RULE OUT INSTANCES OF PEA-SIZE HAIL
FROM THE TALLEST CORES TONIGHT.
OF GREATER INTEREST IS THE RISK OF SEVERE THUNDERSTORMS THURSDAY
EVENING. WARM, MOIST ADVECTION IS SET TO PREVAIL TONIGHT
RESULTING IN NEAR-STEADY TEMPERATURES IN THE 50S EARLY THURSDAY
MORNING WITH DEW POINTS RISING INTO THE 50S AND APPROACHING 60.
A WARM FRONT IS FORECAST TO STALL EAST-WEST ACROSS FAR SOUTHERN
MICHIGAN. HOW QUICKLY THIS FRONT GETS SHUNTED SOUTH BY
DEEPENING CANADIAN LOW PRESSURE IS CRITICAL FOR HOW
THUNDERSTORMS EVOLVE. A STRONG CAP NEEDS TO BE OVERCOME AS
WELL.
THE GENERAL THINKING CONTINUES TO BE THAT ISOLATED
THUNDERSTORMS DEVELOP OVER NORTHERN ILLINOIS AND QUICKLY CONGEAL
INTO A LINE THAT DROPS SOUTHEAST THROUGH THE FORECAST AREA. THE
WINDOW OF OPPORTUNITY REMAINS ABOUT 5P TO 11P EDT, WITH
DAMAGING WIND AND HEAVY RAIN THE PRIMARY HAZARDS FROM LINE
SEGMENTS. ANY DISCRETE STORMS THAT DEVELOP WITHIN THE WARM
SECTOR COULD PRODUCE LARGE HAIL AND EVEN A TORNADO. MUCAPE IN
EXCESS OF 1,000 J/KG AND 0-6KM SHEAR OF 55-60 KNOTS BOLSTER
FORECAST CONFIDENCE, WHILE THE TRIGGER TO BREAK THE CAP IS
LIKELY THE COMBINATION OF AN INCOMING COLD FRONT AND A
STRENGTHENING LOW- LEVEL JET ACROSS CENTRAL IL. RAIN RATES OF 1"
PER HOUR AND BOUNDARY-PARALLEL FLOW WILL RAISE THE CONCERN FOR
FLOODING AS THE NIGHT PROGRESSES, BUT FORWARD SPEED OF THE COLD
FRONT MAY LIMIT THIS RISK OVERALL. DRY CONDITIONS PREVAIL FOR
MOST OF THE AREA BY DAYBREAK FRIDAY.
SHARPLY COOLER ON FRIDAY, ESPECIALLY ALONG THE LAKESHORE WHERE
NORTHERLY FLOW MAY KEEP THOSE COMMUNITIES LOCKED INTO THE 30S ALL
DAY AS HIGH PRESSURE BECOMES CENTERED OVER WESTERN IOWA. RETURN FLOW
SATURDAY OFFERS SLIGHT IMPROVEMENT INTO THE 40S. WARMER SUNDAY AND
THROUGH AT LEAST THE START OF NEXT WEEK AS HIGH PRESSURE OVER THE
SOUTHEAST US PROMOTES WARMING ALONG WITH INCREASED CHANCES FOR
SHOWERS AND STORMS.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 150 PM EDT WED MAR 25 2026
DEAMPLIFYING MID/UPPER LEVEL FLOW PATTERN WILL RESULT IN
STRENGTHENING WARM/MOIST ADVECTION TONIGHT. THIS WARM/MOIST
ADVECTION SHOULD LEAD TO ENOUGH ELEVATED INSTABILITY FOR
ISOLATED-SCATTERED SHOWERS AND STORMS LATE TONIGHT, PARTICULARLY
ALONG AND SOUTH OF US 30. HAVE MAINTAINED PROB30 MENTION AT KFWA
TO COVER THIS POTENTIAL, BUT CONFIDENCE REMAINS TOO LOW TO
INCLUDE THUNDER AT THIS TIME. NEAR TERM GUIDANCE STILL CONTINUES
TO SUGGEST SOME IFR CIG POTENTIAL AT KSBN AT THE NOSE OF THIS
STRONGER LOW LEVEL MOISTURE ADVECTION, BUT CONFIDENCE IN MVFR
CIGS REMAINS HIGHER THAN IFR. GREATER CONVECTIVE POTENTIAL IS
EXPECTED TO HOLD OFF UNTIL AFTER THIS FORECAST VALID PERIOD LATE
THURSDAY AFTERNOON INTO THURSDAY EVENING AS CAPPED CONDITIONS
HOLD FOR A TIME. SOUTH WINDS WILL STRENGTHEN FOR THURSDAY
AFTERNOON DUE TO BETTER MIXING PROFILES, WITH GUSTS TO AROUND 25
KNOTS EXPECTED TOWARD END OF THIS PERIOD AT KFWA.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LMZ043-046.
DISCUSSION...BROWN
AVIATION...MARSILI
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