185
FXUS63 KIWX 061728
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1228 PM EST THU NOV 6 2025
KEY MESSAGES
- SEASONABLE TEMPERATURES EXPECTED INTO FRIDAY. A PERIOD OF RAIN
SHOWERS IS EXPECTED LATE TONIGHT INTO FRIDAY.
- MORE WIDESPREAD SHOWERS ARE EXPECTED SATURDAY AFTERNOON INTO
SUNDAY MORNING, POSSIBLY MIXING WITH A FEW SNOW FLAKES BEFORE
ENDING.
- SHARPLY COLDER AIR ARRIVES BY SUNDAY NIGHT AND LINGERS INTO
EARLY TUESDAY. LAKE EFFECT SNOW SHOWERS POSSIBLE SUNDAY NIGHT
INTO MONDAY.
DISCUSSION
ISSUED AT 355 AM EST THU NOV 6 2025
THE TRAIN OF UPPER LEVEL SYSTEMS REMAINS ACTIVE THROUGH THE NEXT
SEVERAL DAYS. THE AREA IS PRESENTLY UNDER THE CONTROL OF WEAK
RIDGING THAT WILL ALLOW FOR DRY CONDITIONS THROUGH AT LEAST THIS
EVENING, BEFORE THE NEXT WAVE QUICKLY ARRIVES LATE TONIGHT INTO
FRIDAY. CAMS ALL SEEM TO BE IN DECENT AGREEMENT ON A ZONE OF
INCREASED CONVERGENCE AND A BIT OF AN UPTICK IN LOW LEVEL
MOISTURE AHEAD OF THE SYSTEM TO BRING A ROUGHLY 2 TO 4 HOUR
PERIOD OF SHOWERS STARTING LATE TONIGHT (9Z OR SO IN THE NW) AND
THEN PROGRESSING RAPIDLY EAST AND CLEARING THE AREA BY 18Z.
OVERALL QPF AMOUNTS STILL NOT OVERLY IMPRESSIVE, BUT MOST
LOCATIONS SHOULD SEE A TENTH OR 2 BEFORE IT DEPARTS. WINDS WILL
BEGIN TO INCREASE AGAIN THIS EVENING INTO THE OVERNIGHT HOURS
(ALTHOUGH NOT AS STRONG AS THE PAST SYSTEM). THE LATE PASSAGE OF
THE FRONT WILL ALLOW TEMPERATURES FRIDAY TO STILL REACH THE LOW
TO MID 60S.
SATURDAY WILL BE THE CALM BEFORE THE STORM WITH MORE SEASONABLE
TEMPERATURES IN THE 50S AND DRY CONDITIONS. THIS WILL QUICKLY
CHANGE AS A SHORTWAVE RAPIDLY TRANSLATES FROM THE PACIFIC NW NOW
INTO WESTERN IL BY 00Z SUN. STRONG JET DYNAMICS WILL INDUCE A
SFC LOW THAT WILL TRACK QUICKLY ACROSS THE FORECAST AREA SAT
NIGHT INTO EARLY SUNDAY BRINGING A ROUND OF SHOWERS WITH IT. AS
THIS PASSES THROUGH, A DEEP 510 DM OR SO UPPER LOW OVER JAMES
BAY WILL SEND AN EVEN STRONGER TROUGH QUICKLY SOUTH, ACCOMPANIED
BY THE COLDEST AIR SO FAR THIS FALL. AS THE COLD AIR BEGINS TO
ARRIVE, A RAIN/SNOW MIX IS POSSIBLE LATE SAT NIGHT INTO SUNDAY
MORNING AS 850 MB TEMPS DROP BELOW ZERO AND 1000-850 MB
THICKNESS VALUES APPROACH 1300 M IN THE FAR NW TOWARDS 12Z SUN
AND THEN PROGRESS SE FROM THERE. SFC WET-BULB TEMPS WILL LIKELY
STILL BE IN THE MID TO UPPER 30S, PREVENTING A FULL SWITCH OVER
UNTIL LATER SUNDAY WHEN THE BRUNT OF THE COLD AIR ARRIVES. THE
BEST CHANCE FOR LAKE EFFECT SNOW SHOWERS WILL COME SUNDAY NIGHT
INTO MONDAY EVENING. CONFIDENCE DOES LOWER WITH REGARDS TO
EXACTLY WHAT LOCATIONS WILL BE IMPACTED THE MOST AND IF ANY WET
SNOW ACCUMULATIONS WILL OCCUR. OUTSIDE OF THE SNOW SHOWERS,
HIGHS WILL ONLY BE IN THE 30S WITH LOWS IN THE 20S. ONCE WE GET
INTO TUESDAY AND BEYOND, THE PATTERN WILL CALM DOWN CONSIDERABLY
WITH TEMPERATURES SLOWLY MODERATING THROUGH THE REMAINDER OF THE
PERIOD.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1225 PM EST THU NOV 6 2025
A LOW LEVEL RIDGE AXIS WILL DEPART TO THE EAST TODAY, ALLOWING
FOR SOUTHERLY FLOW THROUGH THE REMAINDER OF THE DAY. AS
BOUNDARY LAYER WINDS STRENGTHEN A BIT LATE THIS AFTERNOON, SOME
GUSTS TO AROUND 15 KNOTS ARE POSSIBLE BEFORE THESE GUSTS EASE
EARLY EVENING. LOW LEVEL FLOW WILL THEN STRENGTHEN THIS EVENING
IN ADVANCE OF THE NEXT SHORT WAVE TROUGH ACROSS THE MID MS
VALLEY. LOW LEVEL HEIGHT GRADIENT SHOULD STRENGTHEN THIS EVENING
AND THERE COULD BE JUST ENOUGH LOW LEVEL MIXING TO SUPPORT GUSTS
TO 20 TO 25 KNOTS DURING THE OVERNIGHT HOURS. DEVELOPMENT OF A
LOW LEVEL JET SHOULD SUPPORT LLWS CONDITIONS IN THE 05Z-12Z
TIMEFRAME AND WILL MAINTAIN THIS MENTION FROM THE PREVIOUS TAF
ISSUANCE. PRE-FRONTAL MOISTURE AND STEEPENING MID LEVEL LAPSE
RATES WILL SUPPORT SHOWER DEVELOPMENT TO THE WEST OF THE
TERMINALS LATER THIS AFTERNOON, AND THESE RAIN SHOWERS SHOULD
SHIFT ACROSS THE TERMINALS LATE TONIGHT INTO FRIDAY MORNING.
ISOLATED THUNDER IS POSSIBLE, BUT CONFIDENCE REMAINS TOO LOW
FOR TAF INCLUSION AT THIS TIME. CIGS MAY DETERIORATE BRIEFLY TO
BELOW 2K FEET EARLY FRIDAY IN ASSOCIATION WITH THE BEST PRE-
FRONTAL MOISTURE AND IN VICINITY OF THE COLD FRONT, BUT WILL
CARRY CIGS JUST ABOVE FUEL ALTERNATE CRITERIA WITH THE 18Z TAFS.
GUSTY WESTERLY POST-FRONTAL WINDS ARE EXPECTED ON FRIDAY
(GUSTING TO AROUND 25 KNOTS) WITH CONDITIONS IMPROVING TO VFR
FROM WEST TO EAST AS DRIER LOW LEVEL AIR BUILDS IN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM EST
SATURDAY FOR LMZ043-046.
DISCUSSION...FISHER
AVIATION...MARSILI
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