479
FXUS63 KIWX 160943
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
543 AM EDT FRI OCT 16 2026
KEY MESSAGES
- TURNING MUCH COOLER AND WINDY FOR TODAY WITH LAKE EFFECT RAIN
SHOWERS EXPECTED. THE STRONGEST WIND GUSTS ARE EXPECTED
DOWNWIND OF LAKE MICHIGAN ACROSS BERRIEN AND LA PORTE COUNTIES
WHERE GUSTS TO 45 MPH ARE LIKELY FRIDAY AFTERNOON AND
EVENING. A WIND ADVISORY HAS BEEN HOISTED AS A RESULT.
- CHANCES FOR FROST ARE BEST ON SATURDAY NIGHT, HOWEVER SOME
FROST CANNOT BE RULED OUT TONIGHT.
- AFTER BELOW NORMAL TEMPERATURES THIS WEEKEND, TEMPERATURES
WILL WARM BACK ABOVE NORMAL EARLY NEXT WEEK. ADDITIONALLY, DRY
WEATHER LOOKS TO PERSIST THROUGH MUCH OF NEXT WEEK.
DISCUSSION
ISSUED AT 257 AM EDT FRI OCT 16 2026
AS A MID LEVEL TROUGH DIGS ACROSS THE CENTRAL US, AN UPPER LOW GETS
SHOVED NORTHEASTWARD PUSHING A SURFACE LOW INTO SOUTHEAST
CANADA/NORTHEAST US. AT THE SAME TIME, A 1040 MB SURFACE HIGH SLIDES
SOUTHEASTWARD INTO THE CENTRAL CONUS. THE PRESENCE OF THIS STRONG
SURFACE HIGH OFTEN INDICATES THE ARRIVAL OF A COOLER AIRMASS AND
THAT IS THE CASE THIS TIME. GIVEN OUR DEPARTURE OF ABOVE NORMAL
TEMPERATURES AND THE ARRIVAL OF THIS COOL AIRMASS, WE'LL HAVE SOME
HAZARDS TO CONTEND WITH TODAY AND THIS WEEKEND. FIRST, YESTERDAY'S
COLD FRONT SHIFTS EASTWARD AND THE VIGOROUS VORT MAX ASSOCIATED WITH
THE MID LEVEL TROUGH DIVES THROUGH LK MI LATE THIS AFTERNOON INTO
THIS EVENING. GIVEN THE WARM LAKE AND THE 850 MB TEMPS DIPPING TO
AROUND OR BELOW 0C, LAKE ENHANCEMENT IS EXPECTED TO CAUSE RAIN.
A SURFACE TROUGH IS EXPECTED TO SWING THROUGH THE SOUTHEAST
AREA OF LK MI AROUND 18Z WITH AMPLE LOW LEVEL MOISTURE, LOW
LEVEL WIND CONVERGENCE, AND BUILDING LAKE ENHANCED INSTABILITY.
GIVEN THE MOVEMENT OF THIS TROUGH AND SWIVELING TRAJECTORIES
FROM NORTHWEST TO NORTH, THE AREA WITH THE BEST CHANCE TO SEE
"HIGHER" QPF IS SOUTHERN BERRIEN INTO LAPORTE WHERE 0.25 TO 0.5"
IS FORECAST, TAPERING OFF THE FARTHER AWAY FROM THE LAKE YOU
ARE. THE HEAVIEST OF THE RAIN APPEARS TO GET INTO BERRIEN COUNTY
MIDDAY (15 OR 16Z) AND CONTINUES SWIVELING SOUTHWARD THROUGH
THE AFTERNOON AND INTO THE EVENING. THE OTHER HAZARD IS WIND
GUSTS, WHICH LOOK TO GET UNDERWAY ALONG LK MI- ADJACENT
LOCATIONS AROUND 19 OR 20Z BEFORE PULLING AWAY AROUND 3Z. GIVEN
THE SURFACE TROUGH, THERE COULD BE SOME ISENTROPIC DOWNGLIDE
ENOUGH TO WORK AN ISOLATED 45 KT GUST DOWN TO THE SURFACE.
OTHERWISE, IT APPEARS THAT FREQUENT GUSTS BETWEEN 30 AND 40 MPH
WILL BE POSSIBLE DURING THAT TIME AS LOW LEVEL LAPSE RATES
BECOME CONDUCIVE. THE STRONGEST OF THE GUSTS ARE ADJACENT TO THE
LAKE, TAPERING OFF THE FARTHER AWAY YOU GET. THIS IS WHY THE
WIND ADVISORY WAS HOISTED FOR LK MI- ADJACENT LOCALES.
THE MENTION OF THE COLD AIR ALSO BRINGS TO MIND THE CHANCE FOR
FROST. ESPECIALLY WITH OVERNIGHT LOWS DROPPING INTO THE 30S FROM
FROM TONIGHT/SAT AM TO SUNDAY NIGHT/MON AM AND POTENTIALLY
AGAIN TUE AM. THE MAIN ISSUE WITH FRIDAY NIGHT/SAT AM IS THE
GRADIENT WHICH COULD KEEP WINDS STRONG ENOUGH TO ELIMINATE
FORMATION OF FROST. A LESSER POSSIBILITY IS LAKE CLOUDS HANG ON,
BUT WOULD PROBABLY LEAN TOWARDS SUBSIDENCE ON THE EASTERN SIDE
OF THE LAKE CLOUDS REMOVING THEM. CLOUDS APPEAR TO ALREADY BE
DISSIPATING ON THE NAM BY AROUND 6 TO 9Z FOR MAYBE ALL OF OUR
COUNTIES (LOWEST CONFIDENCE ON LAPORTE TO WHITE COUNTY LINE).
THIS WOULD GIVE AREAS ALONG OR ABOUT IN-15 NORTH OF US-24 ON
INTO MI THE BEST CHANCE TO SEE FROST TONIGHT. SURFACE HIGH
PRESSURE CONTINUES TO POKE INTO THE AREA SATURDAY MORNING WITH
THE STRONGER GRADIENT LURKING TO OUR NORTH. SO, CLOUD COVER
APPEARS LESS OF FACTOR. IT'S OFTEN THAT AS RETURN FLOW BEGINS TO
OCCUR THAT WE GET OUR BEST FROST CHANCES AS WINDS SLACKEN, BUT
THE BOUNDARY LAYER IS ABLE TO GET BACK TO WHAT IT WAS THE
PREVIOUS NIGHT OR POTENTIALLY COLDER. SO, SATURDAY NIGHT HAS THE
BEST CHANCE FOR FROST. THERE IS ALSO THE POSSIBILITY OF A
FREEZE PRIMARILY ALONG AND SOUTH OF US-24 SUN AM WITH A COUPLE
HOURS OF TEMPS RIGHT AROUND THERE THEN.
SURFACE HIGH PRESSURE THEN BECOMES STAGNANT ACROSS THE EASTERN CONUS
AS BLOCKING BUILDS ACROSS THE ATLANTIC. THE NAO/AO BOTH DROP
NEGATIVE DURING THIS TIME. THE UPPER JET ALSO RETREATS BACK UP INTO
CANADA. A SLOW MOVING TROUGH MOVES INTO THE WESTERN CONUS, BUT TAKES
ITS TIME ARRIVING INTO THE AREA POTENTIALLY CONTINUING TO PROVIDE
DRY WEATHER INTO NEXT WEEKEND. TEMPERATURES TREND WARMER WITH HIGHS
RETURNING TO THE 70S DURING THE NEXT WORK WEEK AND LOWS WARMING
SLOWLY THROUGH THE 40S.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 543 AM EDT FRI OCT 16 2026
POST-FRONTAL COLD ADVECTION WILL KEEP MAINLY MVFR CIGS AND GUSTY
WEST-NORTHWEST WINDS GOING TODAY. A DIGGING UPPER LEVEL TROUGH AND
ASSOCIATED SECONDARY LOW LEVEL TROUGH SINK SOUTH THROUGH THE AREA
THIS AFTERNOON BRINGING INCREASING CHANCES FOR SHOWERS AND VIS
RESTRICTIONS, PARTICULARLY AT KSBN WHERE THERE WILL BE LAKE
ENHANCEMENT. THIS TRANSITIONS TO PURE LAKE EFFECT THIS EVENING AT
KSBN WITH ADDITIONAL SHOWER CHANCES AND HIGH MVFR CIGS. WINDS REMAIN
GUSTY AND VEER MORE NORTHERLY OTHERWISE LATER THIS AFTERNOON AND
EVENING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR INZ103-203.
OH...NONE.
MI...WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM EDT THIS
EVENING FOR MIZ177-277.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LMZ043-
046.
GALE WARNING FROM 11 AM THIS MORNING TO 2 AM EDT SATURDAY FOR
LMZ043-046.
DISCUSSION...ROLLER
AVIATION...STEINWEDEL
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