331  
FXUS63 KIWX 271614  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
1214 PM EDT THU MAR 27 2025  
   
KEY MESSAGES  
 
- LOW CHANCES (20-35%) OF RAIN SHOWERS TODAY MAINLY SOUTH OF US  
ROUTE 30 ACROSS NORTHERN INDIANA.  
 
- GREATER CHANCES OF RAIN (60-80%) ARRIVE LATE TONIGHT INTO EARLY  
FRIDAY WITH A FEW THUNDERSTORMS POSSIBLE.  
 
- NOTABLY WARMER FRIDAY THROUGH THE WEEKEND WITH SHOWERS AND SOME  
THUNDERSTORMS. GREATEST CHANCE OF THUNDERSTORMS LATE SUNDAY  
AFTERNOON INTO SUNDAY EVENING.  
 
- WINDY ON FRIDAY WITH SOUTHWEST WIND GUSTS AS HIGH AS 40 MPH  
POSSIBLE IN THE AFTERNOON.  
 
- SHARPLY COLDER MONDAY.  
 
 
   
DISCUSSION  
 
ISSUED AT 350 AM EDT THU MAR 27 2025  
 
LOW LEVEL WARM ADVECTION WILL STRENGTHEN TODAY AS A LOW LEVEL RIDGE  
AXIS BUILDS IN FROM THE WEST. FRONTOGENETIC LOW/MID LEVEL FLOW IN  
WAKE OF THIS LOW LEVEL RIDGE AXIS AND SOME ELEVATED MOISTURE  
RETURN WILL ALLOW FOR THE POTENTIAL OF SOME ISOLATED TO  
SCATTERED LIGHT SHOWERS. PRIMARY LOW LEVEL THETA-E GRADIENT  
SHOULD REMAIN ANCHORED WELL BACK TO THE SOUTHWEST TODAY WITH A  
RELATIVELY DRY SUB-CLOUD LAYER PERSISTING. BASED ON  
GUIDANCE/OBSERVATIONAL TRENDS, HAVE CONTINUED TREND OF PREVIOUS  
FORECAST IN CUTTING BACK NORTHWARD/EASTWARD EXTENT OF POPS  
TODAY. A WEAK MID LEVEL DISTURBANCE TRACKING ACROSS THE GREAT  
LAKES REGION COULD ACTIVATE A SECONDARY FRONTAL ZONE FOR ANOTHER  
AREA OF WEAKER FGEN FORCING ACROSS LOWER MICHIGAN, AND  
PARTICULARLY ACROSS WEST CENTRAL LOWER MICHIGAN. ANY PRECIP WITH  
THIS FORCING WOULD LIKELY BE OF THE TRACE VARIETY HOWEVER.  
 
IN TERMS OF TEMPERATURES TODAY, DEPARTING COLD POOL TO THE  
EASTERN GREAT LAKES EARLY THIS MORNING HAS ALLOWED FOR SOME  
THINNING OF MID LEVEL CLOUDS ACROSS BULK OF THE AREA, ALTHOUGH  
EXPECTING THESE CLOUDS TO FILL BACK IN ACROSS THE WEST AS THE  
FGEN FORCING BECOMES MORE PRONOUNCED LATER DAY. THIS COULD SET  
UP BEST INSOLATION TODAY FOR AREAS EAST OF I-69 AND INTO  
NORTHWEST OHIO WHERE THE POTENTIAL EXISTS FOR HIGHS INTO THE  
UPPER 50S. ELSEWHERE, MODEST WARM ADVECTION WILL BE PARTIALLY  
OFFSET BY BETTER CLOUD COVER WHICH SHOULD KEEP HIGHS IN THE MID  
50S (POSSIBLY LOW 50S IN AREAS OF THICKER CLOUDS FAR WEST-  
SOUTHWEST).  
 
SOME ISOLATED SHOWERS/SPRINKLES MAY LINGER SOUTH OF US ROUTE 24 INTO  
THIS EVENING, BUT STILL EXPECTING GREATER RAIN SHOWER COVERAGE  
DURING THE OVERNIGHT HOURS AS MORE SUBSTANTIAL LOW LEVEL MOISTURE  
GRADIENT SURGES EAST-NORTHEAST FROM THE MID MS VALLEY. OTHER THAN  
STRONGER ADVECTIVE FORCING WITH DEVELOPING WARM FRONTAL BOUNDARY  
LATE TONIGHT INTO FRIDAY, LARGE SCALE MID/UPPER LEVEL SUPPORT IS  
RATHER MEAGER. THE HIGHER THETA-E LOW LEVEL AIR WILL ALSO BE  
ACCOMPANIED BY SOME STEEPER MID LEVEL LAPSE RATES TONIGHT,  
PARTICULARLY INTO EARLY FRIDAY MORNING WHEN A FEW STORMS ARE  
POSSIBLE.  
 
SHOWERS AND A FEW EMBEDDED STORMS WILL CONTINUE THROUGH LATE FRIDAY  
MORNING/EARLY PM BEFORE ENDING AS THE AREA GETS INTO WARM SECTOR.  
FORECAST SOUNDINGS SUGGEST TOP OF BOUNDARY LAYER WINDS AROUND 40-45  
KNOTS WHICH WOULD BE SUPPORTIVE OF SFC WIND GUSTS AS HIGH AS 40  
MPH FRIDAY AFTERNOON ACROSS NORTHERN INDIANA. PROBABILISTIC  
GUIDANCE FROM HIGHER RES SHORT-TERM GUIDANCE SUGGESTS 50-70%  
PROBS OF WIND GUSTS TO 40 MPH BUT SHARPLY DECREASING TO 10-20%  
FOR WIND GUSTS IN EXCESS OF 45 MPH. IT WILL BE WARM ON FRIDAY  
WITH HIGHS RANGING FROM UPPER 60S FAR NORTH TO MID 70S SOUTH.  
 
LULL IN PRECIP CHANCES STILL LOOKS PLAUSIBLE FRIDAY NIGHT INTO EARLY  
SATURDAY AM. BY LATER SATURDAY MORNING, SOUTHWARD SAGGING SFC FRONT  
ACROSS SOUTHERN GREAT LAKES AND RENEWED AREA OF MOISTURE TRANSPORT  
WORKING INTO THE SOUTH FROM THE OHIO VALLEY COULD BE TWO SEPARATE  
FOCAL POINTS FOR RENEWED SHOWER CHANCES. OTHERWISE, IT WILL REMAIN  
MILD ON SATURDAY WITH HIGHS UPPER 60S/LOWER 70S.  
 
A STRONGER SHORT WAVE TROUGH IS STILL EXPECTED TO EMERGE FROM  
CENTRAL CONUS SATURDAY NIGHT INTO SUNDAY. STALLED LOW LEVEL  
BAROCLINIC ZONE AND GOOD FLOW DOWNSTREAM OF THIS FEATURE SHOULD  
SUPPORT ADDITIONAL SHOWERS AND THUNDERSTORMS SUNDAY, WITH PERHAPS A  
WINDOW OF SOME STRONG/SEVERE POTENTIAL GIVEN POTENTIAL OF SOME  
BETTER MID LEVEL LAPSE RATES ADVECTING IN DURING THE AFTERNOON.  
SHEAR PROFILES LOOK SUPPORTIVE OF SOME SEVERE POTENTIAL, BUT  
NORTHWARD EXTENT OF BETTER SFC/NEAR SFC BASED INSTABILITY APPEARS TO  
BE A LIMITING FACTOR AT THIS FORECAST DISTANCE. CONFIDENCE IN  
DETAILS IN MASS FIELDS IS STILL SOMEWHAT LOW GIVEN A WIDE SPREAD IN  
DETERMINISTIC/ENSEMBLE SOLUTIONS WITH SPEED/DEPTH OF MID LEVEL  
TROUGH, BUT GIVEN CONSENSUS LOW LEVEL HEIGHT MINIMUM TRACK AND  
CLIMATOLOGICALLY FAVORED PLACEMENT OF STALLED BAROCLINIC ZONE  
ACROSS FAR NORTHERN INDIANA, STILL FEEL THAT APPROXIMATELY  
SOUTHERN HALF OF THE AREA WOULD HAVE BEST CHANCE FOR STRONG  
STORM POTENTIAL IN A WINDOW FROM LATER SUNDAY AFTERNOON INTO  
SUNDAY EVENING.  
 
STRONG LARGE SCALE FRONTAL RESPONSE WILL KEEP RAIN SHOWERS INTO  
SUNDAY NIGHT/EARLY MONDAY MORNING AS CONDITIONS TURNS SHARPLY  
COLDER. THIS COLDER AIR WILL BE SHORT-LIVED AS A SERIES OF  
ADDITIONAL EASTERN PACIFIC WAVES TO LIKELY BRING MORE  
SHOWERS/POSSIBLE STORMS MIDDLE/LATE NEXT WORK WEEK AS TEMPERATURES  
MODERATE BACK ABOVE NORMAL.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/  
 
ISSUED AT 1213 PM EDT THU MAR 27 2025  
 
VFR/DRY CONDITIONS PERSIST THIS AFTERNOON AND EVENING WITH A  
BKN-OVC CLOUD DECK GENERALLY IN THE 5-10 KFT RANGE. ELEVATED  
SHOWERS, AND PERHAPS A FEW THUNDERSTORMS, ARE THEN ON TARGET TO  
DEVELOP ACROSS NORTHERN IN LATER TONIGHT INTO FRIDAY MORNING IN  
ADVANCE OF A WARM FRONT LIFTING THROUGH THE TERMINALS AROUND  
MIDDAY. ONGOING TOP DOWN SATURATION LIKELY ALLOWS FLIGHT  
CONDITIONS TO LOWER INTO MVFR FOR A TIME FRIDAY MORNING, WITH A  
BRIEF PERIOD OF IFR ALSO POSSIBLE.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...MARSILI  
AVIATION...STEINWEDEL  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab IN Page
The Nexlab OH Page
The Nexlab MI Page
Main Text Page