572  
FXUS63 KIWX 271109  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
709 AM EDT SUN APR 27 2025  
   
KEY MESSAGES  
 
- DRY CONDITIONS TODAY INTO MONDAY WITH PARTLY TO MOSTLY CLEAR  
SKIES. HIGHS TODAY WILL BE IN THE 60S, THEN RISE INTO THE 70S  
MONDAY. LOWS TONIGHT IN THE 40S, THEN IN THE 60S MONDAY  
NIGHT.  
 
- THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA LATE MONDAY NIGHT  
INTO EARLY TUESDAY MORNING. ISOLATED TRONG 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 SOUTHEAST OF I 69,  
WITH THE MAIN THREATS DAMAGING WINDS AND LARGE HAIL. ISOLATED  
TORNADOES ARE POSSIBLE. CONFIDENCE IN SEVERE WEATHER POTENTIAL  
IS MEDIUM.  
 
 
   
DISCUSSION  
 
ISSUED AT 317 AM EDT SUN APR 27 2025  
 
COLD START THIS MORNING WITH A FEW LOCATIONS ACROSS THE  
NORTHWEST PORTIONS OF THE CWA CURRENTLY AS OF 3 AM EDT DOWN TO  
AROUND 33 DEGREES THIS MORNING. KSBN WAS REPORTING 36 DEGREES.  
WILL SEE TEMPERATURES REBOUND LATER TODAY WITH RIDGING PUSHING  
EASTWARD INTO THE REGION AND LIGHT WINDS TURNING MORE  
SOUTHEASTERLY. DRIER AIRMASS STILL IN PLACE WITH DEW POINTS IN  
THE UPPER 30S TO LOW 40S. HIGHS IN THE 60S ACROSS THE AREA  
TODAY.  
 
MONDAY WE START TO SEE SOUTHERLY WINDS INCREASING, GUSTS UP TO  
35 MPH POSSIBLE, WHICH WILL START TO BRING AN INFLUX OF  
MOISTURE WITH DEW POINTS INCREASING INTO THE UPPER 40S TO UPPER  
50S BY MONDAY AFTERNOON. THIS IS AHEAD OF A SURFACE LOW PRESSURE  
SYSTEM THAT PULLS OUT OF THE FOUR-CORNERS REGION AND MOVES  
NORTHEASTWARD TOWARDS THE GREAT LAKES REGION BY TUESDAY. HIGHS  
ON MONDAY WILL BE WARMER YET WITH TEMPERATURES IN THE 70S WITH A  
FEW LOCATIONS IN OUR SOUTHWEST PARTS OF THE CWA PERHAPS GETTING  
INTO THE LOWER 80S. THAT LOW PRESSURE SYSTEM WILL BRING SEVERE  
WEATHER TO EASTERN IA, NORTHERN IL, AND SOUTHERN WI ON MONDAY  
AFTERNOON AND EVENING. FURTHER INFLUX OF MOISTURE WILL CONTINUE  
AHEAD OF THE COLD FRONT INTO THE AREA LATE MONDAY NIGHT INTO  
EARLY TUESDAY AND SURFACE DEW POINTS WILL GET INTO THE 60S BY  
TUESDAY MORNING.  
 
THE RECENT GUIDANCE HAS BEEN INDICATING THAT THE COLD FRONT  
WILL APPROACH OUR AREA A BIT EARLIER THAN ORIGINALLY THOUGHT.  
ARRIVING BY EARLY TUESDAY MORNING. THIS WILL INCREASE CHANCES  
OF SHOWERS AND THUNDERSTORMS TO ENTER THE WESTERN PORTIONS OF  
THE CWA AROUND 1-2 AM EDT TUESDAY. A STRONG STORM WOULD STILL BE  
POSSIBLE AS THE FRONT ARRIVES BUT WITH THE NIGHTTIME ARRIVAL  
WILL HELP TO MITIGATE THE STRENGTH OF THE STORMS. THE EARLIER  
FRONTAL PASSAGE WILL ALSO KEEP A MAJORITY OF THE AREA IN A NOT  
SO IDEAL DIURNAL HEATING SETUP AND FURTHERMORE CAUSE INCREASED  
CLOUD COVER ACROSS THE AREA WHICH WILL HELP TO MITIGATE DIRECT  
SOLAR INSOLATION AND SUBSEQUENT SURFACE WARMING. MU CAPE VALUES  
ON TUESDAY AFTERNOON WILL BE AROUND 1000-1500 J/KG, MID LEVEL  
LAPSE RATES AROUND 6-7 DEG/KM, AND BULK SHEAR VALUES OF 30 TO  
35 KTS. THESE INGREDIENTS DO MAKE FOR THE POTENTIAL FOR SOME  
ORGANIZED SEVERE THREATS INCLUDING STRONG GUSTY WINDS AND HAIL.  
A FEW ISOLATED TORNADOES WOULD NOT BE OUT OF THE QUESTION AS  
HELICITY VALUES SOUTHEAST PORTIONS OF THE CWA WILL BE AROUND  
100 M2/S2. SPC DAY 3 CONVECTIVE OUTLOOK DOES CURRENTLY HAVE OUR  
SOUTHWEST PORTIONS OF THE CWA IN A SLIGHT RISK ON TUESDAY.  
 
THE COLD FRONTAL BOUNDARY WILL PUSH SOUTHEAST BY EARLY  
WEDNESDAY MORNING BUT WILL BECOME MORE ORIENTATED IN A EAST TO  
WEST DIRECTION OVER THE SOUTHERN PORTIONS OF THE AREA AND BECOME  
MORE OF A QUASI-STATIONARY BOUNDARY BEFORE PUSHING BACK  
NORTHWARD AS A WARM FRONTAL BOUNDARY ON WEDNESDAY BRINGING  
ISENTROPIC SHOWERS AND A FEW AFTERNOON THUNDERSTORMS ON  
WEDNESDAY. ANY STORMS ARE NOT EXPECTED TO BE SEVERE AT THIS TIME.  
HIGHS ON WEDNESDAY WILL BE IN THE 60S ACROSS THE AREA WITH THE  
WARMER TEMPERATURES FOR THE SOUTHERN HALF OF THE AREA WHERE A  
FEW LOCATIONS MAY SEE LOW 70S.  
 
THE BOUNDARY PUSHES FURTHER NORTHWARD ON THURSDAY AGAIN WITH  
INCREASED CHANCES OF RAIN SHOWERS AND EMBEDDED THUNDERSTORMS,  
WITH THE BETTER CHANCES FOR T-STORMS ON THURSDAY AFTERNOON.  
HIGH TEMPERATURES WARM BACK INTO THE UPPER 60S AND LOW 70S  
ALBEIT TEMPORARILY AS TROUGHING OVER THE CENTRAL CONUS PUSHES  
EASTWARD AND BRINGS COOLER TEMPERATURES AND DRIER CONDITIONS TO  
THE AREA INTO THE WEEKEND. FRIDAY THROUGH SUNDAY HIGH  
TEMPERATURES WILL ONLY BE IN THE LOW TO MID 60S.  
 
 
   
AVIATION /12Z TAFS THROUGH 12Z MONDAY/  
 
ISSUED AT 657 AM EDT SUN APR 27 2025  
 
VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE PERIOD,  
WITH CALM WINDS THIS MORNING STRENGTHENING SLIGHTLY FROM THE  
E-SE THROUGH THE AFTERNOON AND EVENING. MOSTLY CLEAR OUTSIDE OF  
PERIODS OF SCATTERED HIGH CLOUDS.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...FROST ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING FOR  
INZ005>008-012-014-103-104-116-203-204.  
OH...NONE.  
MI...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ078>081-177-  
277.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...ANDERSEN  
AVIATION...MCD  
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