459
FXUS63 KIWX 121034 AAA
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
539 AM EDT TUE AUG 12 2025
KEY MESSAGES
- REMAINING HOT AND HUMID TODAY, AND AGAIN THIS WEEKEND. PEAK
AFTERNOON HEAT INDICES THIS WEEKEND WILL BE WELL INTO THE 90S.
- BETTER CHANCES (50-70%) FOR SHOWERS AND STORMS ARRIVE MID
AFTERNOON TUESDAY THROUGH TUESDAY EVENING. ANY STORMS WILL
CARRY A THREAT FOR LOCALLY HEAVY RAINFALL AND GUSTY WINDS.
DISCUSSION
ISSUED AT 329 AM EDT TUE AUG 12 2025
RIDGING HAS CONTINUED TO MOVE EAST TO SOUTHEAST AND THIS ALLOWED
FOR SOME CONVECTION TO DEVELOP OVER THE NORTHWEST PERIPHERY OF
THE RIDGE INTO BERRIEN COUNTY EARLIER THIS MORNING. THIS
ACTIVITY HAS SINCE MOVED NORTHEAST INTO CENTRAL MI. A BREAK IN
THE ACTIVITY OVER THE NEXT 5-7 HOURS BEFORE THE COLD FRONT
ASSOCIATED WITH A TROUGH PUSHING INTO THE GREAT LAKES REGION
TODAY.
BETTER CHANCES OF SHOWERS/THUNDERSTORMS WITH 50-70%
CHANCE LATER TODAY STARTING OVER OUR NORTHWESTERN PORTIONS OF
THE CWA AFTER ABOUT 1 PM EDT AND THEN SPREADING SOUTHEASTWARD
INTO THE REMAINING AREAS OF THE FORECAST AREA THIS EVENING. SPC
DOES CURRENTLY HAVE OUR ENTIRE AREA IN A MARGINAL RISK FOR SEVERE
THUNDERSTORMS TODAY. LOCALIZED HEAVY RAINS ARE POSSIBLE WITH THE
EFFICIENT RAINFALL PRODUCTION WITH PWATS NEAR 1.75 INCHES WITHIN
THIS HUMID AIRMASS AND THE SLOWER STORM MOTION ALONG THE FRONTAL
BOUNDARY. THE OTHER MAIN THREAT WOULD BE THE GUSTY OUTFLOW WINDS
ESPECIALLY WITH ANY PRECIPITATION LOADING. SOME OF THE GUSTS GETTING
TO AROUND 40-50 MPH WOULD NOT BE SURPRISING. HIGHS TODAY IN THE
UPPER 80S TO EVEN A FEW LOCATIONS IN THE LOW 90S. DEW POINTS WILL BE
IN THE LOW TO MID 70S.
THE COOL FRONT AND ANY ACCOMPANIED SHOWERS AND EMBEDDED
THUNDERSTORMS WILL MOVE SOUTHEAST THROUGH THE REMAINDER OF THE
AREA BY MIDDAY WEDNESDAY, BUT NOT BEFORE OUR FAR SOUTHEAST
LOCATIONS SUCH AS LIMA, OH WILL HAVE CONTINUED CHANCES OF
SHOWERS AND THUNDERSTORMS. HOWEVER, AT THIS TIME THE DIURNAL
TIMING SHOULD KEEP ANY STORMS FAIRLY TAMED. DRIER AND A BIT
COOLER AIRMASS WILL USHER INTO THE AREA IN THE WAKE OF THE
FRONTAL PASSAGE AND ON WEDNESDAY HIGHS WILL ONLY BE IN THE LOW
TO MID 80S AND HUMIDITY LEVELS AND CLOUD COVER WILL BEGIN TO
DECREASE THROUGH THE DAY. THURSDAY WILL SEE SIMILAR COMFORTABLE
CONDITIONS AND MOSTLY SUNNY SKIES.
RIDGING BUILDING OVER THE SOUTHERN CONUS WILL BEGIN TO PUSH
NORTHWARD AND WE WILL SEE A BIT WARMER TEMPERATURES AND
INCREASING HUMIDITIES BEGIN TO MOVE INTO THE AREA ON FRIDAY.
HIGHS ON FRIDAY IN THE MID TO UPPER 80S. WHILE THIS WEEKEND WE
WILL SEE TEMPERATURES GET BACK INTO THE UPPER 80S TO LOWER 90S
ALONG WITH DEW POINTS BACK IN THE 70S TO MAKE FOR ANOTHER BOUT
OF MUGGY WEATHER. THERE IS STILL A BIT OF UNCERTAINTY AS TO HOW
LONG THIS NEXT SURGE OF HEAT REMAINS BUT SOME INDICATIONS THAT A
TROUGH BEGINS TO BUILD INTO THE GREAT LAKES REGION WHICH COULD
MODERATE TEMPERATURES ONCE AGAIN, BUT HIGH AMPLITUDE BROAD
RIDGING DOES LOOK TO BUILD OVER THE CENTRAL CONUS EVEN WELL UP
INTO CENTRAL CANADA. IT REALLY WILL DEPEND ON EXACTLY WHERE THE
RIDGING SETS UP BUT IF WE ARE LUCKY WE MAY HAVE THE TROUGHING
SET UP OVER OUR AREA KEEPING US A BIT COOLER, HOWEVER THIS COULD
PUT US INTO A ACTIVE CONVECTIVE PATTERN AT LEAST FOR OUR EASTERN
SECTIONS OF THE CWA. WILL NEED TO KEEP AN EYE ON THIS IN
COMING DAYS TO SEE EXACTLY HOW THE SYNOPTIC PATTERN EVOLVES.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 536 AM EDT TUE AUG 12 2025
FEW CHANGES NEEDED FOR THE 12Z TAFS. THE CURRENT FORECAST IS
STILLON TRACK WITH DRY CONDTIONS THIS MORNING BEFORE RAIN/STORMS
ARRIVE LATER IN THE DAY. PREDOMINANTLY VFR CONDITIONS ARE
EXPECTED AT THE TAF SITES TODAY, ESPECIALLY THIS MORNING AS
CLOUDS SLOWLY MOVE IN. A STALLED FRONTAL BOUNDARY TO OUR WEST
WILL SLOWLY EDGE EAST/SOUTHEASTWARD AND BRING CHANCES FOR
RAIN/STORMS TO THE FORECAST AREA TODAY. RIGHT NOW, MUCH OF THE
STORM ACTIVITY REMAINS CONFINED TO NORTHERN ILLINOIS. CHANCES
FOR RAIN/STORMS ACROSS THE FORECAST AREA INCREASE FROM WEST TO
EAST THIS AFTERNOON. RAIN/STORMS SHOULD ARRIVE TO KSBN BETWEEN
18Z-21Z AND TO KFWA AFTER 21Z THIS AFTERNOON, WITH MEDIUM
CONFIDENCE IN MVFR CEILINGS AND VISIBILITIES (MAYBE IFR BRIEFLY
WITH ANY STRONGER STORMS/HEAVY RAIN). RAIN/STORMS WILL LIKELY
LINGER INTO THE EARLY OVERNIGHT HOURS BEFORE DIMINISHING BEFORE
DAYBREAK WEDNESDAY. WINDS WILL BE OUT OF THE SOUTHWEST TODAY
BETWEEN 5-15 KTS (ON THE STRONGER SIDE OF THIS RANGE BY THE
AFTERNOON).
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...ANDERSEN
AVIATION...JOHNSON
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