862
FXUS63 KIWX 070843
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
343 AM EST FRI NOV 7 2025
KEY MESSAGES
- A BAND OF RAIN SHOWERS (ALONG WITH POSSIBLY A RUMBLE OF
THUNDER) WILL TRACK ACROSS THE REGION THIS MORNING. THERE IS A
HIGH PROBABILITY (GREATER THAN 90 PERCENT) THAT MOST
LOCATIONS WILL SEE AT LEAST ONE TENTH OF AN INCH OF RAINFALL.
- MORE WIDESPREAD RAIN IS EXPECTED SATURDAY NIGHT INTO EARLY
SUNDAY, ESPECIALLY NORTH OF US-24. RAIN MAY MIX WITH OR CHANGE
ENTIRELY TO SNOW WITH SOME ACCUMULATIONS POSSIBLE.
- TURNING SHARPLY COLDER SUNDAY NIGHT WITH LAKE EFFECT SNOW
DEVELOPING SUNDAY NIGHT THROUGH MONDAY. WHILE DETAILS REMAIN
UNCERTAIN ON THE TIMING, PLACEMENT, AND INTENSITY OF THESE
LAKE EFFECT BANDS, THE POTENTIAL EXISTS FOR SEVERAL INCHES OF
ACCUMULATION IN FAVORED CORRIDORS FROM SUNDAY NIGHT THROUGH
MONDAY.
DISCUSSION
ISSUED AT 343 AM EST FRI NOV 7 2025
AN AREA OF INCREASING CONVERGENCE AND LIFT EXTENDING FROM NW
LOWER MI TO CENTRAL IL, WAS WELL DEPICTED ON RADAR AS AN
EXPANDING AREA OF SHOWERS AND EVEN SOME OCCASIONAL LIGHTNING
STRIKES. THIS WILL TRAVERSE THE AREA THIS MORNING, LIKELY
CLEARING SE PARTS OF THE AREA BY 18Z. THE FAST MOVEMENT WILL
LIMIT OVERALL QPF, BUT MOST LOCATIONS SHOULD SEE BETWEEN 1 AND 2
TENTHS OF AN INCH, WITH ANY AREAS THAT SEE A THUNDERSTORM MAYBE
PUSHING A QUARTER INCH. AS THE SHOWERS END, AN AREA OF CLOUDS
WILL LINGER FOR A FEW HOURS BEFORE SUBSIDENCE ALLOWS FOR
CLEARING SKIES AND A CHANCE FOR TEMPERATURES TO REBOUND INTO
THE LOW TO MID 60S. ANOTHER WEAK TROUGH DIVES SOUTH TONIGHT WITH
SOME MODELS TRYING TO SPIT OUT SOME LIGHT PRECIP NEAR LK MI,
BUT THE MOISTURE AXIS SEEMS TO WAIT TILL LATE TONIGHT AND BY THE
TIME IT TRIES TO GET ITS ACT TOGETHER IT IS NEARLY OUT OF THE
AREA. WILL MAINTAIN SOME SLGT CHC TO LOW CHC POPS, BUT SUSPECT
THESE MAY GET WHITTLED AWAY IN THE NEXT FORECAST.
VERY ACTIVE PATTERN KICKS INTO FULL GEAR SATURDAY INTO EARLY
NEXT WEEK AS SEVERAL FEATURES RESULT IN A SOMEWHAT COMPLICATED
FORECAST. A CLIPPER TYPE WAVE WILL DIVE INTO SE NEBRASKA BY 12Z
SAT AND THEN TRANSLATE EAST AND NORTHEAST INTO THE AREA BY 6Z
SUN. MODELS ARE STRUGGLING ON DEEPENING OF THIS FEATURE AS A
120-130 KT JET STREAK ROUNDS THE BASE OF THE WAVE. HIGH
CONFIDENCE EXISTS ON A LARGE AREA OF PRECIP, MAINLY IN THE FORM
OF RAIN, EXISTING ALONG AND NORTH OF THE LOW TRACK. CONFIDENCE
QUICKLY DROPS WITH REGARDS TO HOW FAST COLD AIR BEGINS TO WRAP
INTO LOCATIONS NW OF THE LOW TRACK, POSSIBLY CHANGING ANY RAIN
TO A RAIN/SNOW MIX OR ALL SNOW LATE SAT NIGHT INTO SUN MORNING.
STRONG FGEN FORCING IS NOTED ON THE NW SIDE WHICH COULD HELP
OVERCOME WET BULB TEMPS IN THE MID TO MAYBE UPPER 30S. GRIDS
STILL REFLECT A MIX FOR THE TIME BEING GIVEN WE ARE STILL A FEW
DAYS OUT, BUT TRENDS WILL NEED TO BE WATCHED. SOME LAKE RESPONSE
WILL OCCUR SUNDAY AS 850 MB TEMPS BEGIN TO FALL FURTHER AND
INCREASING DELTA TS GET THE LAKE EFFECT MACHINE WARMED UP. WHILE
POPS ARE RATHER EXTENSIVE SUNDAY, THEY ARE LIKELY TO NEED
REFINEMENT AS INLAND EXTENSION AND DURATION MAY NOT BE AS MUCH
AS NOTED. WITH HIGHS STILL MANAGING TO GET ABOVE FREEZING AND
"WARM" GROUND TEMPS ANY SNOW SHOULD MELT OFF THAT MANAGES TO
FALL.
MODELS ALSO CONTINUE TO STRUGGLE ON THE EVOLUTION OF THE MAIN
LES BAND SUNDAY NIGHT INTO AT LEAST MONDAY AS ANOTHER TROUGH
DIVES SOUTH IN ASSOCIATION WITH A DEEP UPPER LOW WHICH WILL
BREAK AWAY FROM JAMES BAY. SEVERAL HINTS FOR A MESOLOW EVOLUTION
ARE SUGGESTED, WHICH WILL MAKE PREDICTING ANY POSSIBLE SNOW
AMOUNTS 3 DAYS OUT RATHER DIFFICULT GIVEN THE TRANSITORY NATURE
OF THE BAND. THERE WILL BE PLENTY OF INSTABILITY AND MOISTURE TO
WORK WITH, AS WELL AS A FAVORABLE TIME FRAME (HOURS OF DARKNESS
INTO EARLY MONDAY) TO ALLOW BETTER CHANCES FOR ACCUMULATIONS TO
STICK AROUND AND MAYBE CREATE SOME SLICK SPOTS ON ROADS IN THE
HEAVIER SNOWSHOWERS. IN ADDITION, HIGHS MONDAY MAY STRUGGLE TO
REACH THE MID 30S, ALSO ALLOWING THE SNOW TO POSSIBLY STICK
AROUND. WHILE CLOSER TO THE LAKE THE SNOW MAY BE FLUFFIER IN
NATURE, SUFFICIENT WATER CONTENT COULD CAUSE SOME TREE BRANCH
DAMAGE ON TREES STILL HOLDING ANY LEAVES. CURRENT FORECAST
DEPICTS THE POTENTIAL OF SEVERAL INCHES OF SNOW IN NW LAPORTE
COUNTY WITH LIGHTER AMOUNTS AWAY FROM THE LAKE. IT IS FAR TO
EARLY TO FOCUS ON SPECIFIC AMOUNTS YET GIVEN ALL THE VARIABLE.
A NW FLOW WILL PERSIST INTO TUESDAY WITH SOME LIGHT RAIN/SNOW
SHOWERS POSSIBLE BEFORE THE MAIN TROUGH PULLS AWAY AND ALLOWS
FOR A TREND TO DRIER AND SLOWLY MODERATING CONDITIONS.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1250 AM EST FRI NOV 7 2025
VFR CONDITIONS DETERIORATING TO MVFR LATE TONIGHT INTO EARLY FRI
AM AS AN OCCLUDING FRONT MOVES THROUGH THE AREA. A PERIOD OF
IFR CONDITIONS IS POSSIBLE AROUND FRONTAL PASSAGE/JUST
AFTERWARDS (12-15Z AT KSBN/14-18Z KFWA), BUT CONFIDENCE IS LOW.
LIGHT RAIN SHOWERS WILL ALSO ACCOMPANY THE FRONT-POTENTIALLY
WITH A RUMBLE OF THUNDER. SOUTHERLY WINDS WILL GUST TO AROUND
25KTS THROUGH THE MORNING, THEN SHIFT TO THE WEST-SOUTHWEST
THROUGH THE AFTERNOON (NORTHWEST AT KSBN AFTER 2Z). LLWS TO
45-50 KNOTS IS LIKELY AHEAD OF THE SYSTEM (PARTICULARLY AT KFWA
WHERE GUSTS ARE LIKELY TO BE MORE INTERMITTENT UNTIL MORNING).
AS OF THIS WRITING THE PRECIPITATION EXTENDS FROM NORTHERN LAKE
MI SOUTHWESTWARD INTO KORD/KMQB. LIGHTNING IS BEST FURTHER
SOUTH, HOWEVER MAY NEED TO AMEND KSBN TO ADD POTENTIAL FOR
-TSRA/VCTS DEPENDING ON HOW THINGS EVOLVE THE NEXT COUPLE HOURS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST SATURDAY FOR LMZ043-046.
DISCUSSION...FISHER
AVIATION...MCD
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