526
FXUS63 KIWX 281905
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
305 PM EDT MON APR 28 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA LATE
TONIGHT INTO EARLY TUESDAY MORNING. SEVERE STORMS ARE NOT
EXPECTED.
- SCATTERED THUNDERSTORMS ARE POSSIBLE TUESDAY AFTERNOON INTO
EARLY TUESDAY EVENING. THE BEST POTENTIAL FOR STRONG TO SEVERE
THUNDERSTORMS WILL BE EAST OF IN-15, WITH THE MAIN THREATS
BEING DAMAGING WINDS AND LARGE HAIL. THE SEVERE WEATHER
THREAT IS CONDITIONAL AND CONFIDENCE THAT SEVERE WEATHER
HAPPENS IS LOW TO MEDIUM.
- RAIN THREATS RETURN WEDNESDAY AND CONTINUE INTO LATE WEEK WITH
AFTERNOON THUNDERSTORMS POSSIBLE BETWEEN WEDNESDAY NIGHT AND
THURSDAY NIGHT.
- DRIER AND COOLER WEATHER LOOKS TO RETURN THIS WEEKEND.
DISCUSSION
ISSUED AT 254 PM EDT MON APR 28 2025
AN AREA OF LOW PRESSURE MOVES FROM THE DAKOTAS TO THE NORTHERN GREAT
LAKES AREA BETWEEN TODAY AND TONIGHT AS A LARGE TROUGH GETS SHEARED
OUT ACROSS THE PLAINS STATES. LOCALLY, A WARM FROM FRONT ASSOCIATED
WITH THE AFORMENTIONED LOW PRESSURE SYSTEM IS PUSHED NORTHWARD
THROUGH THE AREA THIS EVENING. THIS ALLOWS BETTER 60 DEGREE DEW
POINTS TO CREEP INTO THE AREA BETWEEN 8PM THIS EVENING THROUGH 8PM
TUESDAY. MEANWHILE, THE BETTER MOISTURE AXIS WORKS INTO THE AREA
JUST BEFORE 6Z TONIGHT THROUGH TUESDAY AFTERNOON OUT IN FRONT OF A
COLD FRONT MOVING THROUGH THE AREA. THERE IS 1500 J/KG OF MUCAPE AND
AROUND 750 J/KG OF SBCAPE FORECAST TO BE MOVING THROUGH THE AREA
WITH THE ARRIVAL OF THE MOISTURE AXIS AND BETTER SHEAR BEGINS TO
POKE INTO THE AREA BETWEEN 9 AND 12Z. DURING THE OVERNIGHT HOURS,
IT'S OFTEN WHAT'S LEFT OF CONVECTION FROM THE NORTH THAT DETERMINES
WHAT SORT OF SEVERE POTENTIAL ARRIVES WITH OVERNIGHT CONVECTION IN
OUR NECK OF THE WOODS. WITH CONVECTIVE INHIBITION AND SOME QUESTION
ABOUT A TRIGGER FOR STORMS IN THE NORTHERN PLAINS, WHAT ARRIVES HERE
CONTAINS SOME UNCERTAINTY. THE BETTER LOW LEVEL TURNING OF WINDS IS
ACTUALLY WITH THE OVERNIGHT CHANCE, BUT WITHOUT THE BETTER HEATING
WITH SOME QUESTION ABOUT IF WE'LL EVEN SEE STORMS DURING THAT TIME,
THE TORNADO THREAT IS LOW. CANNOT RULE OUT A STRONG WIND OR HAIL
THREAT WITH ANY CONVECTION THAT DOES ARRIVE DURING THE OVERNIGHT
INTO THE MORNING THOUGH AS MID LEVEL LAPSE RATES REACH AROUND 8C/KM
WITH THE EML. THE COLD FRONT ARRIVES DURING THE LATE MORNING IN OUR
EXTREME NORTHWEST AND MAY BE ABLE TO SPARK SOME SHOWERS AND STORMS
DURING THE AFTERNOON (MAYBE 1 OR 2PM AT THE EARLIEST), BUT WHAT THE
OVERNIGHT CONVECTION LEAVES BEHIND DEBRIS CLOUD-WISE WILL HELP
DETERMINE WHAT INSTABILITY IS AROUND FOR STORMS TO USE FOR THE
AFTERNOON. THE ULTIMATE RESTING PLACE FOR THE OUTFLOW/COLD POOL
BOUNDARY WILL ALSO BE KEY. THE EML APPEARS TO BE WASHED OUT AND MID
LEVEL LAPSE RATES ARE REDUCED FOR THE AFTERNOON. THE DCAPE VALUES
ARE ALSO UNDERWHELMING. EVEN SHEAR VALUES APPEAR REDUCED WITH 30 TO
MAYBE 40 KTS OF EFFECTIVE SHEAR AND MARGINAL TO WEAK HELICITY
VALUES. SOME OF THESE VALUES COULD BE CONVECTIVELY IMPACTED BY THE
MODEL CARRYING THROUGH THE CONVECTION/OUTFLOW BOUNDARY. IT STILL
APPEARS THAT EAST OF IN-15 OR SOUTH OF US-24 WILL BE THE MAIN AREA
OF CONCERN SHOULD THINGS BE ABLE TO REFIRE. IT SHOULD BE OUT OF THE
AREA BY AROUND 00Z OR 01Z.
THE COLD FRONT ENDS UP DRAPED TO OUR SOUTH ON A WEST TO EAST PLANE
WEDNESDAY MORNING WITH SURFACE HIGH PRESSURE TO OUR NORTH. WE'LL
WAITING FOR THE SOUTHERN PART OF THE SHEARED ENERGY, WHICH HAS
CUTOFF FROM THE FLOW, TO BE CAPTURED BY THE NEXT ARRIVING TROUGH AND
BROUGHT TO THE AREA WEDNESDAY NIGHT. WITH AN AREA OF LOW PRESSURE
PASSING BY TO OUR NORTHWEST, WE'LL BE IN THE WARM SECTOR FOR THE
MORNING INTO THE AFTERNOON AND SO WE'LL PROBABLY HAVE SOME THUNDER,
BUT THERE REMAINS SOME UNCERTAINTY ON SEVERE WEATHER POTENTIAL. SOME
LINGERING RAIN MAY CONTINUE THROUGH FRIDAY WHEN THE FINAL AREA OF
DEFORMATION/FINAL TROUGH SWINGS THROUGH.
THE SURFACE HIGH PRESSURE FINALLY NOSES IN ON SATURDAY AND DRIES
THINGS OUT FOR THE WEEKEND. WE CURRENTLY HAVE UPPER 30S FOR HIGHS
SATURDAY MORNING SO WE'LL NEED TO WATCH FOR FROST FORMATION THEN,
BUT THE LATE DEPARTURE OF THE MOISTURE AND ARRIVAL OF THE SURFACE
HIGH MAY KEEP US OUT OF THE FROST. TIMING WILL BE KEY.
ONE INTERESTING ASPECT OF THIS FORECAST IS THAT BLOCKING BEGINS TO
SET UP ACROSS THE ATLANTIC SO THAT BY DAY 7 (MAY 4TH OR 5TH), STRONG
ANOMALOUSLY POSITIVE HEIGHTS BUILD OVER GREENLAND. A STRONG RIDGE
SETS UP ACROSS THE SOUTHEASTERN US AND A TROUGH SETS UP ACROSS THE
WESTERN CONUS. ON THE EARLY SIDE OF THIS BLOCK BEING SET UP,
THERE COULD BE SOME RAIN CHANCES, BUT THE LONGER THIS LASTS, THE
GREATER CHANCE THAT ANTECEDENT CONDITIONS COULD KEEP THE AREA
DRY FROM POP SHOWERS AND STORMS.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1242 PM EDT MON APR 28 2025
VFR CONDITIONS WILL PERSIST THIS AFTERNOON INTO TONIGHT WITH
SOUTHERLY FLOW ON THE INCREASE. GUSTS 20-25 KTS WILL BE COMMON
WITH LLJ DEVELOPMENT MID EVENING INTO EARLY TUESDAY LEADING TO
LLWS ACROSS NORTHERN IN. LOW CONFIDENCE REMAINS ON WHETHER
WEAKENED CONVECTION HOLDS TOGETHER INTO THE TERMINALS TUESDAY
MORNING. HELD ONTO THE PROB30 MENTION FOR A BRIEF
SHOWER/STORM CHANCE DURING THIS TIME.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ043-046.
DISCUSSION...ROLLER
AVIATION...STEINWEDEL
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