779
FXUS63 KIWX 280548
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
148 AM EDT MON APR 28 2025
KEY MESSAGES
- THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA LATE MONDAY NIGHT
INTO EARLY TUESDAY MORNING. ISOLATED STRONG TO SEVERE STORMS
ARE POSSIBLE WEST OF I 69, WITH THE MAIN THREAT DAMAGING
WINDS. CONFIDENCE IS LOW AS STORMS WILL BE WEAKENING AND THEY
ARRIVE AROUND 1-2 AM ET WHEN CONDITIONS ARE LESS FAVORABLE.
- SCATTERED STRONG TO SEVERE STORMS ARE POSSIBLE TUESDAY
AFTERNOON AND EVENING. THE BEST POTENTIAL WILL BE EAST OF
IN-15, WITH THE MAIN THREATS DAMAGING WINDS AND LARGE HAIL. A
TORNADO OR TWO ARE POSSIBLE. CONFIDENCE IN SEVERE WEATHER
POTENTIAL IS MEDIUM.
- RAIN THREATS RETURN WEDNESDAY AND CONTINUE INTO LATE WEEK, BUT
THE THUNDER THREAT LOOKS RESTRICTED TO THURSDAY WITH A LOW
SEVERE STORM THREAT AS WELL.
- DRIER AND COOLER WEATHER LOOKS TO RETURN NEXT WEEKEND.
DISCUSSION
ISSUED AT 225 PM EDT SUN APR 27 2025
SURFACE HIGH PRESSURE SHIFTS EAST AND STALLS ALONG THE WESTERN
ATLANTIC STALLING THE PATTERN TO AN EXTENT. MEANWHILE, A TROUGH
SHIFTS EASTWARD AND IS PUSHED NORTHWARD INTO THE GREAT LAKES/
SOUTHERN CANADA AND A WARM ADVECTION WING ARRIVES MONDAY. THIS
INCREASES THE HIGHS ON MONDAY AND INCREASES DEW POINTS MONDAY NIGHT
AND TUESDAY MORNING INTO THE 60S. THIS MOISTURE STREAM PUSHES TROUGH
BETWEEN MONDAY NIGHT AND TUESDAY MORNING AND THERE IS SOME
INSTABILITY TO WORK WITH IN MODELS WITH SOME SURFACE BASED
CONTRIBUTION. NOW THERE DISCREPANCIES IN THE TIMING OF THE SHEAR
DURING THIS TIME. WHEN THE MOISTURE STREAM ARRIVES IN THE WEST 6Z IT
MAY BE THAT THAT'S WHEN THE SHEAR DECREASES AND PERHAPS THINGS
WEAKEN AND GO OUTFLOW DOMINANT. THE MAIN QUESTION WILL BE WHAT
HAPPENS EAST OF IN-15 OR THE I-69 CORRIDOR ON TUESDAY WHERE THE COLD
FRONT IS BEING MODELED TO END UP. IS THERE DEBRIS CLOUDS LEFT BEHIND
THAT AFFECTS THE RESULTANT INSTABILITY, ESPECIALLY IF THE COLD FRONT
MIGHT BE COMING THROUGH EARLIER IN THE AFTERNOON SO THAT THERE'S
LESS TIME IN PEAK HEATING TO RECOVER. WE HAVE THE SHEAR FOR A
TORNADO POTENTIAL MONDAY NIGHT INTO EARLY TUESDAY MORNING (MAYBE 2AM
TO 10AM), BUT GIVEN THE NIGHT TIME ARRIVAL, INSTABILITY WILL BE KEY.
THERE'S STILL A SMALL CHANCE THAT TUESDAY AFTERNOON (MAYBE 1PM TO
9PM) SEES A TORNADO, BUT BY THIS TIME, SHEAR IS LESSENED AND THERE'S
QUESTIONS ABOUT IF INSTABILITY CAN RECOVER IN TIME. SEVERE HAIL ALSO
HAS A CHANCE WITH MID LEVEL LAPSE RATES BETWEEN 6.5 TO 8 C/KM AT
TIMES AND DEPENDING ON INSTABILITY. DAMAGING WIND IS ALSO A THREAT.
TRAINING CELLS MAY RESULT IN FLOODING IF THE STORMS THAT TRAIN
BECOME STRONG ENOUGH TO PRODUCE HEAVY ENOUGH RAIN RATES. PWATS ARE 2
SDS ABOVE NORMAL SO THAT'S IN HEAVY RAIN'S FAVOR.
THEN, AS A CYCLONIC WAVE BREAK OCCURS AND AN UPPER LOW PARKS
OVER THE SOUTHWESTERN US, A TROUGH COMES INTO THE WESTERN US AND
BRINGS THAT ENERGY TOWARDS THE AREA FOR WEDNESDAY
AFTERNOON/NIGHT. THIS IS AS THE SURFACE BOUNDARY FROM THE
MONDAY/TUESDAY EVENING STALLS JUST SOUTH OF OUR AREA. CHANCES
FOR SCATTERED RAIN LOOKS TO CONTINUE WEDNESDAY EVENING THROUGH
THURSDAY. WHEN THE UPPER LOW CENTER PASSES BY TO OUR NORTHWEST,
PERHAPS THERE MAY BE A TIMEFRAME WHERE THE WARM SECTOR PASSES
THROUGH THAT THUNDER COULD BE POSSIBLE, BUT SEVERE WEATHER
APPEARS TO BE LESS LIKELY. THE MAIN THREAT FROM ALL OF THIS
WOULD BE POTENTIAL FLOODING FROM THE REPEATED RAIN FALL CHANCES.
THE TROUGH FINALLY TAKES THIS MOISTURE OUT OF HERE BY FRIDAY EVENING
AS HIGH PRESSURE NOSES INTO THE AREA BRINGING A RETURN TO DRIER
WEATHER. WE'LL HAVE TO WATCH FOR FROST ON SATURDAY AND SUNDAY
MORNINGS WITH UPPER 30S FORECAST AT THIS POINT FOR THE AREA AS
MORNING LOWS.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 141 AM EDT MON APR 28 2025
VFR CONDITIONS WITH LIGHT SOUTHEAST WINDS TO START THE PERIOD.
AS WE HEAD INTO THE AFTERNOON WINDS SHIFT MORE SOUTHWARD,
INCREASING TO 13-15 KNOTS WITH GUSTS TO AROUND 25 KNOTS.
GUSTINESS WILL PERSIST BEHIND A WARM FRONT TUESDAY NIGHT BUT
MAY BECOME LESS FREQUENT INTO TUE AM AS WE DECOUPLE, WITH LLWS
TO 45-50 KNOTS AT BOTH SITES STARTING AROUND 3-4Z. CHANCES FOR
RAIN AND POSSIBLY A FEW THUNDERSTORMS CLOSER TO 9-12Z TUE AM,
JUST BEYOND THIS TAF PERIOD. CONFIDENCE IS LOW AT THIS TIME AS
MODELS ARE CONFLICTED WITH REGARDS TO TIMING THE APPROACH OF A
COLD FRONT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 PM EDT
TUESDAY FOR LMZ043-046.
DISCUSSION...ROLLER
AVIATION...MCD
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