264
FXUS63 KIWX 091059
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
659 AM EDT WED SEP 9 2026
KEY MESSAGES
- A WARM AND MORE HUMID AIRMASS WILL BE IN PLACE INTO EARLY
THURSDAY. CLOUD COVER AND PRECIPITATION MAY CAUSE LARGE
VARIATIONS IN TEMPERATURES WEDNESDAY.
- THERE IS A 30% TO 60% CHANCE OF SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH EARLY THURSDAY MORNING. THERE IS A MARGINAL
RISK FOR ISOLATED SEVERE STORMS BETWEEN 3-9 PM ET THIS EVE,
MAINLY ALONG AND SOUTH OF US 24. HEAVY RAIN, LIGHTNING, AND
ISOLATED DAMAGING WIND GUSTS ARE THE PRIMARY THREATS IN THE
STRONGEST STORMS
- THERE IS A MODERATE SWIM RISK FOR NORTHERN BERRIEN COUNTY, MI
BEACHES ALONG LAKE MI TODAY, AND FOR ALL OF BERRIEN COUNTY, MI
AND LA PORTE COUNTY, IN THURSDAY. BREAKING WAVES AND CURRENTS
ARE EXPECTED.
DISCUSSION
ISSUED AT 428 AM EDT WED SEP 9 2026
A PRE-FRONTAL TROUGH WILL CROSS THE AREA FROM WEST TO EAST TODAY,
BRINGING CHANCES FOR SHOWERS AND A FEW THUNDERSTORMS. SPC HAS AREAS
GENERALLY ALONG AND SOUTH OF US 24 IN A MARGINAL RISK FOR ISOLATED
STRONG-SEVERE STORMS, BUT CONFIDENCE IN THIS OCCURRING IS LOW. IF
STRONGER STORMS DO DEVELOP, THEY WILL NOT BE WIDESPREAD. THE MAIN
THREAT WOULD BE DAMAGING WINDS, FREQUENT LIGHTNING, AND HEAVY
DOWNPOURS. AREA IN THE MARGINAL RISK SHOULD HAVE BETTER INSTABILITY
AS THE FEATURE MOVES THROUGH TOWARDS THE MID-LATE AFTERNOON HOURS
(1500 J/KG), WITH ABOUT 20-30 KNOTS OF 0-6 KM AGL SHEAR (BETTER
SHEAR ARRIVES IN THE LATE AFTERNOON, BUT IT'S DISJOINTED FROM THE
BETTER INSTABILITY). PLENTY OF MOISTURE AROUND WITH DEWPOINTS IN THE
60S, 70S. HIGH TEMPERATURES WILL BE IN THE LOW TO MID 80S
ALONG/NORTH OF US 24, AND THE UPPER 80S FURTHER SOUTH. HEAT INDICES
IN THE SOUTHERN AREAS COULD REACH INTO THE LOW-MID 90S DURING PEAK
HEATING THIS AFTERNOON.
SOUTHERLY WINDS WILL STRENGTHEN SLIGHTLY OUT OF THE SOUTHWEST
THROUGH THE DAY, WITH A PERIOD OF WESTERLY FLOW POSSIBLE BRIEFLY
BEHIND THE PASSING TROUGH. WAVES ON LAKE MI AROUND ST. JOSEPH,
MI NORTHWARD MAY CLIMB TO AROUND 2-3 FEET BY MID AFTERNOON, AND
AROUND 1-2 FEET FURTHER SOUTH. HAVE A MODERATE SWIM RISK FOR
LAKE MI BEACHES ALONG THE NORTHERN BERRIEN COUNTY, MI SHORELINE
TODAY (INCLUDING SILVER BEACH COUNTY PARK AND TISCORNIA PARK).
WAVES REACH AROUND 2-3 FEET FOR SOUTHERN BERRIEN COUNTY, MI AND
LA PORTE COUNTY, IN BY THURSDAY AS WELL WITH NORTHERLY FLOW
PICKING UP SLIGHTLY TONIGHT INTO THU. HAVE A MODERATE SWIM RISK
FOR BOTH COUNTIES ACCORDINGLY. TODAY, A MODERATE TO STRONG SOUTH
TO NORTH FLOWING LONGSHORE CURRENT IS EXPECTED, WHICH WILL LEAD
TO STRONG STRUCTURAL CURRENTS ON THE SOUTH SIDE OF
PIERS/BREAKWALLS. RIP CURRENTS ARE POSSIBLE WITHIN THE SANDBARS.
ALL CURRENT TYPES ARE POSSIBLE ON THURSDAY.
BECOMING COOLER AND LESS HUMID BEHIND A PASSING COLD FRONT ON
THURSDAY. CHANCES (30-50%) FOR SHOWERS AND THUNDERSTORMS REMAIN
MAINLY ALONG/SOUTH OF US 30 DURING THIS PERIOD. SEVERE WEATHER IS
NOT EXPECTED. IT'S POSSIBLE THAT THE FRONT REACHES FURTHER SOUTH AT
A QUICKER PACE THAN CURRENTLY FORECAST, WHICH WOULD REDUCE POPS FOR
THURSDAY ALL TOGETHER. HIGHS WILL BE AROUND 80 DEGREES, WITH LOWS IN
THE 50S, LOW 60S.
WHILE WE WILL STILL HAVE WEAK UPPER TROUGH OVERHEAD ON FRIDAY (SOME
MODELS SUGGEST MORE RIDING), SURFACE HIGH PRESSURE REMAINS IN
CONTROL WITH EASTERLY FLOW IN THE LOW LEVELS. MOST OF THE GUIDANCE
REMAINS DRY IN THIS PERIOD, WITH THE EXCEPTION BEING THE FAR SOUTH
WHERE SOME MODELS PRODUCE LIGHT PRECIP. LEFT OUT FOR NOW GIVEN LOW
CONFIDENCE. HIGHS WILL BE AROUND 80 DEGREES, WITH LOWS IN THE 50S,
LOW 60S.
HIGHS WARM BACK INTO LOW-MID 80S FOR THE WEEKEND INTO MONDAY, WITH
AN UPPER LEVEL RIDGE FRIDAY NIGHT BECOMING MORE ZONAL WITH TIME,
LEAVING US SUSCEPTIBLE TO SHORTWAVES KICKING OFF SHOWERS AND STORMS.
HAVE LOW CHANCES (20-30%) EACH DAY THROUGH THE PERIOD. BETTER
POTENTIAL (30-50% CHANCES) ARRIVE MID-LATE WEEK AS AN UPPER LEVEL
LOW DROPS INTO THE NORTHERN PLAINS AND A BROAD SURFACE LOW
DEVELOPING NEAR IA DEEPENS AND LIFTS INTO ONTARIO/QUEBEC. THIS WILL
BRING A COLD FRONT THROUGH SOMETIME BETWEEN TUE-WED. HIGHS REMAIN IN
THE UPPER 70S, LOW-MID 80S, COOLEST WEDNESDAY.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 652 AM EDT WED SEP 9 2026
PREDOMINANTLY VFR CONDITIONS AT THE TERMINALS WITH A PRE-FRONTAL
THROUGH MOVING THROUGH. MVFR PERIODS ARE POSSIBLE WITH ANY
HEAVIER SHOWERS/ISOLATED STORMS TODAY, FIRST AT KSBN THIS
MORNING THEN AT KFWA LATE MORNING INTO THE AFTERNOON. ADDED A
CHANCE FOR THUNDER AT KFWA AROUND 18-22Z, AND HAVE SHOWERS PRIOR
TO THAT WITH POTENTIAL FOR CEILINGS AROUND 2500 FT. UPSTREAM OBS
DO SHOW SOME LOWER CEILINGS, BUT UNCERTAIN IF THEY WILL SURVIVE
AS THE TROUGH MOVES EASTWARD. S-SE WINDS (CALM RIGHT NOW AT
KFWA) INITIALLY BECOME MORE WESTERLY THROUGH THE PERIOD. THERE
COULD BE A RUMBLE OF THUNDER AT KSBN THROUGH EARLY AFTERNOON,
BUT CONFIDENCE WAS TOO LOW TO INCLUDE RIGHT NOW (TRENDS WEST
HAVE BEEN ON THE DECREASE). BR/FG IS POSSIBLE AT BOTH SITES, BUT
ESPECIALLY KFWA LATE TONIGHT INTO THU AM, BUT CONFIDENCE WAS TOO
LOW TO INCLUDE A FORMAL MENTION IN THE TAF. MOST LIKELY TIME
WOULD BE 9-12Z.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MCD
AVIATION...MCD
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