506
FXUS63 KIWX 230611
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
111 AM EST MON FEB 23 2026
KEY MESSAGES
- WINTER WEATHER ADVISORIES ARE IN EFFECT FOR LAKE EFFECT SNOW
FOR PORTIONS OF NORTHWEST AND NORTH CENTRAL INDIANA ALONG WITH
SOUTHWEST LOWER MICHIGAN.
- ADDITIONAL LAKE EFFECT SNOW ACCUMULATIONS TONIGHT INTO EARLY
MONDAY OF 2 TO 5 INCHES EXPECTED, WITH LOCALLY HIGHER AMOUNTS
POSSIBLE ACROSS BERRIEN AND LAPORTE COUNTIES. IMPACTS TO THE
MONDAY MORNING COMMUTE ARE LIKELY.
- RAIN AND SNOW CHANCES RETURN FOR WEDNESDAY AND THURSDAY BUT
CONFIDENCE IN EXACT DETAILS SUCH AS PRECIP AMOUNTS AND TYPES
REMAIN LOW. TEMPERATURES TREND WARMER LATER IN THE WORK WEEK
BEHIND THIS SYSTEM.
DISCUSSION
ISSUED AT 310 PM EST SUN FEB 22 2026
WINTER WEATHER ADVISORIES HAVE BEEN EXTENDED INTO STARKE AND
MARSHALL COUNTIES DUE TO THE POTENTIAL OF HEAVIER LAKE EFFECT SNOW
SHOWERS LATER TONIGHT INTO EARLY MONDAY. OTHERWISE, ALL HEADLINES
REMAIN AS IS WITH THE AFTERNOON PACKAGE.
A LARGER SCALE UPPER LEVEL LOW WILL CONTINUE TO SHIFT EASTWARD TO
THE MID ATLANTIC TONIGHT WHILE CONTINUING TO ACQUIRE A NEGATIVE
TILT. UPSTREAM OF THE LOCAL AREA, ANOTHER MORE COMPACT UPPER
LEVEL SHORT WAVE WILL DROP ACROSS THE WESTERN/SOUTHERN GREAT
LAKES THROUGH EARLY EVENING. MUCH COLDER LOW LEVEL AIR WILL
CONTINUE TO WORK INTO NORTHWEST INDIANA AS THIS OCCURS. LAKE
EFFECT/ENHANCED SNOW SHOWERS HAVE DIMINISHED IN INTENSITY THIS
AFTERNOON AFTER STRONGER BANDING AFFECTED SOUTHWEST LOWER
MICHIGAN INTO ELKHART/KOSCIUSKO/NOBLE COUNTIES. THIS LOW LEVEL
FGEN CONTRIBUTION HAS BEEN MORE PROGRESSIVE TO THE SOUTHEAST AND
WEAKENED THIS AFTERNOON.
THE CONCERN HEADING INTO TONIGHT WILL BE A SHARPENING LAKE AGGREGATE
TROUGH IN RESPONSE TO THE LOW LEVEL COLD CORE WORKING SOUTH ACROSS
THE WESTERN GREAT LAKES. A MORE MERIDIONAL FLOW SETUP AND OPTIMAL
FETCH RAISES THE CONCERN FOR A MORE DOMINANT BAND SETUP, ESPECIALLY
LATE TONIGHT/EARLY MONDAY. LAKE EFFECT PARAMETERS ARE NOT
OVERWHELMING IN TERMS OF DEPTH OF CONVECTIVE BOUNDARY LAYER AND
INVERSION HEIGHTS. ONE POSITIVE FACTOR FOR MORE INTENSE BANDING
TONIGHT WHICH PLAYED SOME ROLE EARLIER TODAY WAS A BROADER
SCALE LOW LEVEL FGEN SIGNAL (950-925MB). THE COMBINATION OF THE
COLD CORE DROPPING SOUTH ACROSS THE WESTERN GREAT LAKES AND
RESIDUAL MORE MODIFIED AIR FROM COLLECTIVE GREAT LAKES INFLUENCE
SHOULD ALLOW ANOTHER STRONG LOW LEVEL FGEN AXIS TO POSSIBLY
ENHANCE LAKE EFFECT BANDING TONIGHT. THIS FGEN FORCING MAY BE
MORE TRANSITORY IN NORTHEAST TO SOUTHWEST FASHION THIS EVENING
AS A VORT LOBE ON NORTHERN PERIPHERY OF THE DEPARTING LONGWAVE
TROUGH ROTATES BACK TO WEST, ALLOWING A WEAK LOW LEVEL THERMAL
RIDGE ACROSS EASTERN GREAT LAKES TO SHIFT WEST INTO SE LOWER
MICHIGAN. RAP NEAR TERM PROGS SUGGEST THIS MORE TRANSITORY FGEN
FORCING COULD BECOME MORE ANCHORED ACROSS NW INDIANA LATE
TONIGHT/EARLY MONDAY. THE OTHER CONCERN IS THAT IF THIS FGEN
FORCING CAN ENHANCE A MORE DOMINANT BAND OR BANDS, THIS WOULD
ALLOW FOR STRONG LIFT IN A SHALLOW BASED DENDRITIC GROWTH ZONE
FOR HIGH SNOW TO LIQUID RATIOS OF 20-30:1.
ONE ITEM OF HIGH UNCERTAINTY IS THE POTENTIAL ORIENTATION OF ANY
DOMINANT BANDING LATE TONIGHT, WHETHER IT WOULD BE STRICTLY NORTH TO
SOUTH ORIENTED ACROSS NW INDIANA/FAR SW LOWER MI OR POSSIBLY
EXHIBIT SOME ARCING BACK TO THE SOUTHEAST IN RESPONSE TO THE
FGEN ENHANCEMENT. GIVEN THE ABOVE FACTORS AND THE POTENTIAL
IMPACTS TO MONDAY MORNING COMMUTE, DID EXTEND THE WINTER WEATHER
ADVISORY INTO STARKE/MARSHALL COUNTIES. LOCATIONS FARTHER TO
THE EAST INCLUDING KOSCIUSKO/ELKHART SHOULD BE MORE IN THE
TRANSITORY PORTION OF THIS EVOLUTION, WITH BRIEF HEAVIER SNOW
RATES POSSIBLE THIS EVENING BEFORE FOCUS SHIFTS TO THE WEST. FOR
MOST OF WINTER WEATHER ADVISORY AREA, HAVE KEPT 2-5" ADDITIONAL
WITH LOCALLY HIGHER AMOUNT POTENTIAL. 12Z HREF OUTPUT CONTINUES
TO SUGGEST THIS POTENTIAL OF LOCALLY HIGHER AMOUNTS COULD BE
MAXIMIZED SW BERRIEN CO, INTO LAPORTE CO. LAKE EFFECT SNOW WILL
GRADUALLY DIMINISH MIDDAY MONDAY INTO THE AFTERNOON AS
INVERSION HEIGHTS LOWER AND MID LEVEL DRYING OCCURS WITH
APPROACH OF LOW LEVEL RIDGE AXIS.
TEMPERATURES WILL MODERATE TOWARD MIDWEEK (MID 30S TO LOWER 40S BY
WED) IN ADVANCE OF THE FIRST PIECE OF SHEARED EASTERN PACIFIC ENERGY
WHICH EMANATES FROM CUT-OFF NEGATIVE UPPER HEIGHT ANOMALY OFF THE
PACIFIC NW COAST. WINDY CONDITIONS ARE EXPECTED TO DEVELOP TUESDAY
IN RESPONSE AHEAD OF ASSOCIATED COLD FRONT, WITH AN EVENTUAL
SOUTHWARD SAGGING FRONTAL BOUNDARY STALLING ACROSS THE SOUTHERN
GREAT LAKES ON WEDNESDAY. THIS STALLED BOUNDARY COULD SET THE
STAGE FOR FAVORABLE STORM TRACK OF NEXT MORE SIGNIFICANT SHORT
WAVE KICKING OUT OF THE EASTERN PACIFIC CUT-OFF FROM LATE
WEDNESDAY INTO THURSDAY. GFS DETERMINISTIC REMAINS MORE
AMPLIFIED WITH MID/UPPER TROUGH AND THUS A RESULTANT HIGHER
IMPACT MIXED PRECIP SYSTEM FOR LATE WED/THU. UKMET/EC/CANADIAN
ALL HAVE TRENDED TO A BIT WEAKER WITH THIS TROUGH AND THUS MORE
SUPPRESSED WITH MIXED PRECIP POTENTIAL. GIVEN INITIAL SHEARED
NATURE OF THIS SYSTEM AND TIMING UNCERTAINTY WITH THE INGESTION
INTO MAIN BELT OF WESTERLIES, DIFFICULT AT THIS FORECAST
DISTANCE TO RESOLVE GUIDANCE SPREAD. IT IS INTERESTING TO NOTE
HOWEVER, THE GEFS MEAN FIELDS DO INDICATE MORE SUPPRESSION THAN
THE GFS OPERATIONAL RUN. THIS WILL BE A SYSTEM THAT WILL BE
MONITORED IN NEXT SEVERAL FORECAST CYCLES FOR POTENTIAL IMPACTS
ACROSS PORTIONS OF THE AREA LATE WED/THU.
LOOKING AHEAD, CONFIDENCE REMAINS MEDIUM TO HIGH IN WARMING TEMPS
FRIDAY/SATURDAY BEFORE ADDITIONAL POTENTIAL W-NW FLOW WAVES DRAG
ANOTHER FRONT SOUTH INTO THE REGION. CONFIDENCE IS ON THE LOW SIDE
IN SOUTHWARD EXTENT OF COLD AIR PENETRATION LATE NEXT WEEKEND INTO
EARLY NEXT WEEK GIVEN EXPECTED LOW AMPLITUDE NATURE OF FLOW.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1258 AM EST MON FEB 23 2026
PREDOMINANTLY MVFR CONDITIONS EXPECTED AT THE TAF SITES, WITH
KSBN DROPPING TO IFR VISIBILITIES AT TIMES WITHIN A HEAVIER LAKE
EFFECT SNOW BAND. KFWA IS MOST LIKELY TO JUMP TO VFR AT TIMES
THROUGH THE OVERNIGHT, AND THEN AGAIN MONDAY AFTERNOON.
UNCERTAINTY EXISTS REGARDING EVOLUTION OF LAKE EFFECT SNOW
SHOWERS ONGOING AT THE MOMENT. AS OF THIS WRITING, THERE APPEAR
TO BE TWO DOMINANT BANDS EMERGING. ONE IS EXTENDING DOWN THE
LONG AXIS OF LAKE MI (NEARLY HUGGING THE WESTERN MI SHORELINE)
AND EXTENDING BETWEEN KSBN/KEKM DOWN TO KASW. THE OTHER (LESS
ORGANIZED) BAND ALONG THE WI/IL SHORELINE INTO KMGC/K65/KASW AND
INTO KFWA. WINDS ARE N-NW, WITH A MORE NORTHERLY FETCH ALONG
THE WEST MI SHORELINE AND MORE NORTHWESTERLY FETCH TOWARDS
CHICAGO/MILWAUKEE. A TROUGH IS SHIFTING DOWN ACROSS CENTRAL-
LOWER MI AND WILL CROSS THE TERMINALS OVERNIGHT. MODELS ARE
STILL SHOWING DIFFERENT POSSIBILITIES WITH REGARDS TO HOW THE
MORE DOMINANT BAND EVOLVES-WITH SOME CONGEALING THE BANDS AND
RAPIDLY SHIFTING SOUTHWEST AS THEY RAPIDLY DIMINISH-AND THEN
OTHERS KEEPING A LINGERING BAND FOR A LONGER TIME NEAR KSBN THAT
GRADUALLY MOVES SOUTHWEST AND MERGES WITH THE OTHER.
FOR NOW ASSUMED A MIXED SOLUTION, KEEPING IFR POTENTIAL UNTIL
10Z AT KSBN AND INTERMITTENT MVFR VISIBILITIES/VIS AT KFWA
UNTIL 9Z BEFORE THE TROUGH AXIS MOVES THROUGH. HAVE SNOW SHOWERS
OVERALL AT BOTH TERMINALS UNTIL 18Z TOMORROW (BOTH LES/TROUGH
INDUCED). KSBN STILL HAS THE POTENTIAL TO DROP TO LIFR AT TIMES
IF THE MORE INTENSE BAND STRENGTHENS AND PARKS OVER KSBN-BUT
WASN'T CONFIDENT ENOUGH TO INCLUDE IN TAF GIVEN MOST OBS
BETWEEN 1-4SM IN THE BAND AS OF THIS WRITING.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER WEATHER ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
INZ005.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR INZ012-014-103-104-203-204.
OH...NONE.
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ078-177-277.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...MCD
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