018
FXUS63 KIWX 132351
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
751 PM EDT FRI MAR 13 2026
KEY MESSAGES
- A STRONG STORM SYSTEM WILL BRING RAIN AND THUNDERSTORMS LATE
SUNDAY INTO SUNDAY NIGHT. SEVERE WEATHER IS POSSIBLE SUNDAY
AFTERNOON INTO SUNDAY NIGHT.
- ACCUMULATING SNOW IS EXPECTED MONDAY INTO TUESDAY, MAINLY IN
NORTHWEST IN AND SOUTHWEST MI.
- TEMPERATURES MID 60S TO NEAR 70 ON SUNDAY WILL CRASH INTO THE
20S BY MONDAY. TUESDAY MORNING WIND CHILLS NEAR ZERO.
DISCUSSION
ISSUED AT 126 PM EDT FRI MAR 13 2026
THE 990 MB LOW PRESSURE SYSTEM TRAVERSING ACROSS THE GREAT LAKES
TODAY DEPARTS TONIGHT TAKING THE STRONG 60-65 KT LOW LEVEL JET WITH
IT. GIVEN THE STRONG PRESSURE GRADIENT AND MIXING UP TO AROUND 850-
800 MB, AT LEAST WIND ADVISORY WINDS OF AROUND 45 MPH OR GREATER
LASTS UNTIL AT LEAST 00Z AND QUITE POSSIBLY FOR 1 TO 4 MORE HOURS IN
NW OH.
THIS TRANSITIONS TO A DRY DAY FOR SATURDAY AS MID LEVEL HEIGHTS RISE
AND SURFACE HIGH PRESSURE PASSES THROUGH THE AREA. WITH THE COLD
FRONT THAT WENT THROUGH THIS MORNING, EXPECT HIGH TEMPERATURES TO BE
AROUND 5 DEGREES COOLER FOR SATURDAY WITH 40S ACROSS MOST OF THE
BOARD.
AS WE HEAD TOWARDS SUNDAY, A PACIFIC WAVE DEEPENS OVER THE ROCKIES
AND A PHASED UPPER JET AND PV HOOK LOOK CONTINUES TO HELP DEEPEN THE
LOW PRESSURE SYSTEM AS IT MOVES THROUGH THE AREA QUICKLY SUNDAY
EVENING/NIGHT. THE THETA-E PLUME ARRIVES AROUND 12Z SUNDAY WITH
AROUND 50 DEGREE DEW POINTS AT THE SURFACE. GIVEN THE ARRIVAL OF THE
PLUME, THERE COULD BE SOME CLOUDS AROUND AND SO WE'LL HAVE TO SEE
WHAT STATE INSTABILITY IS IN FOR A SEVERE WEATHER CHANCE DURING THE
AFTERNOON AND EVENING. A STRONG EML GETS IN HERE DURING THE LATE
NIGHT TO EARLY MORNING HOURS WITH AROUND 8C/KM MID LEVEL LAPSE
RATES. THERE APPEARS TO BE SOME WEAKENING OF IT BY THE TIME WE GET
TO THE AFTERNOON WITH MORE LIKE 6.5 TO 7.5 C/KM MID LEVEL LAPSE
RATES, BUT THAT'S ADEQUATE ENOUGH TO STILL CAUSING SEVERE HAIL AS A
SEVERE OUTCOME IF ANY ISOLATED CELLS ARE ABLE TO FORM OUT IN FRONT
OF THE COLD FRONT. ISOLATED CELLS ARE NOT A GIVEN, THOUGH, BECAUSE
IT APPEARS THAT THE WARM SECTOR IS RATHER DRY AND COULD BE CAPPED
UNTIL THE COLD FRONT ARRIVES. IF WE ARE ABLE TO REMAIN DRY AND MIXED
IN THE WARM SECTOR, WE COULD SEE 35 TO 45 MPH GUSTS THERE AS WELL.
EFFECTIVE SHEAR APPEARS RATHER BORDERLINE WITH POCKETS OF 30 KTS
AROUND THE AREA, BUT THE EFFECTIVE HELICITY IS ALSO ONE THAT COULD
CONTRIBUTE TO EMBEDDED VORTICIES IN WHAT APPEARS TO BE A SQUALL
LINE OR QLCS TYPE OF EVENT. THIS WOULD ALLOW DAMAGING WINDS AND
A TORNADO TO ALSO BE A THREAT ALONG THAT LINE. STORM MOTION
WILL PROBABLY FACTOR INTO THE DAMAGING WIND POTENTIAL GIVEN THAT
WE'LL START WITH 40 TO 50 KT MOTIONS AND THIS RAMPS UP TO 60 TO
90 MOTIONS (USING BUNKERS MOTIONS) BY THE END OF THE EVENT.
GIVEN THE UNCERTAINTY ABOUT IF ISOLATED CELLS CAN FORM IN FRONT
OF THE LINE THE ONSET TIME IS IN QUESTION. AT THIS POINT, THE
COLD FRONT MOVES THROUGH THE AREA BY AROUND 9Z.
COLD AIR IS ABLE TO COME IN ON THE BACK SIDE OF THIS VIGOROUS LOW
PRESSURE SYSTEM TO THE TUNE OF -15 TO -20C AT 850 MB. WIND
CHILLS FALL TO THE SINGLE DIGITS MONDAY NIGHT AND EARLY TUESDAY.
THERE COULD BE SOME LIGHT SNOW ASSOCIATED WITH THE UPPER LOW OR
ON THE BACKSIDE OF THE FRONT IF THE COLD AIR ARRIVES QUICKLY
ENOUGH, BUT IT'S MORE THE LAKE EFFECT SNOW ASPECT THAT WILL
LIKELY BRING ACCUMULATING SNOW TO THE AREA. WITH THE LAKE
TEMPERATURE BEING AROUND 40F OR SO, THIS SHOULD ALLOW 20 TO 25
DEGREE DELTA T VALUES STARTING AROUND 12Z MONDAY AND CONTINUING
THROUGH 00Z TUESDAY EVENING. INVERSION HEIGHTS MAY ONLY BE
AROUND 3 KFT HIGH MONDAY MORNING, BUT WITH THE ARRIVAL OF THE
COLD AIR, WILL RISE TO BETWEEN 6 TO 8 KFT BY AROUND MIDDAY
MONDAY, WHICH INDICATES HIGH END SNOWFALL. THESE INVERSION
HEIGHTS BEGIN TO COME BACK DOWN MIDDAY TUESDAY AND TUESDAY
AFTERNOON. THE INITIAL ENVIRONMENT HAS THE CLOUD LAYER RISING
INTO THE DGZ WHICH IS GOOD FOR STRONGER SLRS. HOWEVER, WE BEGIN
TO LOSE LOW LEVEL MOISTURE MONDAY AFTERNOON AND WE GET VERY COLD
MONDAY NIGHT SO THAT WILL MAKE SLRS WEAKER FOR SNOW. STILL SOME
TIME FOR CHANGES IN THE MAJOR PIECES HERE, BUT THE ECMWF, GFS,
AND NBM ALL INDICATE THAT AT LEAST ADVISORY SNOWFALL IS POSSIBLE
DURING THIS PERIOD. FOR OUR GRID POPULATION PERIOD THROUGH 00Z
MON EVENING, I HAVE 2 TO 5 INCHES OF SNOW, HIGHEST CLOSER TO THE
LAKE. BOTH MONDAY AND TUESDAY APPEAR TO HAVE GUSTY WINDS AS
WELL.
WARM ADVECTION IS QUICK TO RETURN TUESDAY NIGHT AND THERE COULD BE
SOME COMBINATION OF RAIN AND SNOW WITH THIS. OFTEN TIMES THIS KIND
OF SET UP LEADS TO AN ONSET SNOW TO RAIN TRANSITION. TEMPERATURES
CONTINUE TO TREND WARMER AND ALLOW MORE 50 DEGREE HIGHS TO RETURN BY
THE END OF THE WEEK. MODELS ALSO TRY TO BRING ANOTHER TROUGH IN BY
THE OF THE WORK WEEK, BUT THEY VARY ON HOW DEEP OR TRANSIENT THE
TROUGH IS MEANING THE SYSTEM COULD ALSO PASS BY TO OUR NORTH.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 746 PM EDT FRI MAR 13 2026
SYNOPTIC NORTHWESTERLY WINDS HAVE BEEN GRADUALLY WEAKENING OVER
THE LAST SEVERAL HOURS AND WILL CONTINUE TO DO SO THIS EVENING.
A FEW REMAINING GUSTS UP TO 35 TO 45 MPH WILL BE POSSIBLE
THROUGH 04Z FOR BOTH TAF SITES. OTHERWISE, VFR CONDITIONS WILL
PREVAIL THROUGH THE REMAINDER OF THIS TAF PERIOD.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LMZ043-046.
DISCUSSION...ROLLER
AVIATION...ANDERSEN
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