570
FXUS63 KIWX 212034
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
334 PM EST SAT FEB 21 2026
KEY MESSAGES
- A COMBINATION OF SYSTEM SNOW AND LAKE ENHANCED SNOW WILL BRING
SOME LIGHT SNOW ACCUMULATIONS THROUGH SUNDAY, WITH GREATEST
ACCUMULATIONS OF 1 TO 3 INCHES DOWNWIND OF LAKE MICHIGAN.
- A PERIOD OF MORE ORGANIZATION OF LAKE EFFECT SNOW BANDS IS
EXPECTED SUNDAY NIGHT INTO EARLY MONDAY MORNING. THIS PERIOD REPRESENTS
THE GREATEST POTENTIAL FOR THE HIGHER SNOWFALL RATES AND
IMPACTS TO TRAVEL. A WINTER WEATHER ADVISORY IS IN EFFECT LATE
TONIGHT THROUGH EARLY MONDAY AFTERNOON FOR CASS MI, BERRIEN
MI, LAPORTE IN, AND ST. JOSEPH IN COUNTIES.
- ADDITIONAL RAIN AND SNOW CHANCES FOR WEDNESDAY AND THURSDAY
BUT EXTENT OF THESE CHANCES AND PRECIP TYPES REMAIN OF LOW
CONFIDENCE.
- TEMPERATURES TREND WARMER LATE WORK WEEK.
DISCUSSION
ISSUED AT 330 PM EST SAT FEB 21 2026
A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR CASS MI/BERRIEN/ST.
JOSEPH IN/LAPORTE COUNTIES FROM 06Z TONIGHT TO 18Z MONDAY. THIS
EVENT WILL HAVE A FEW DIFFERENT PHASES. THERE IS LOWER CONFIDENCE IN
NOTABLE IMPACTS TONIGHT INTO SUNDAY WITH LIGHT SYSTEM/LAKE ENHANCED
SNOW. THE POTENTIAL OF HIGHER SNOWFALL RATES AND GREATER
IMPACTS STILL LOOKS TO BE SUNDAY EVENING INTO MONDAY AM.
UPSTREAM FLOW IS HIGHLY PERTURBED THIS AFTERNOON WITH AN INITIAL
UPPER VORT MAX LIFTING ACROSS NORTHERN ILLINOIS. VORTICITY ADVECTION
DOWNSTREAM OF THIS FEATURE IS YIELDING SOME ELEVATED RETURNS PER
REGIONAL RADAR MOSAIC. A RELATIVELY DRY 3-7K FOOT LAYER IS
LIMITING PRECIP IN ASSOCIATION WITH THIS FORCING. DEPTH OF THIS
DRY LAYER MAY BE SMALL ENOUGH TO ALLOW SOME SEEDER FEEDER
PROCESS AND A FEW FLURRIES THROUGH LATE AFTERNOON. ON THE HEELS
OF THIS LEAD WAVE WILL BE ANOTHER STRONGER UPPER VORT MAX WHICH
IS EXPECTED TO DIG ACROSS TN VALLEY OVERNIGHT TONIGHT AS AN
UPPER SPEED MAX ROUNDS THE BASE OF THE TROUGH. AS THIS OCCURS,
THE UPPER TROUGH IS EXPECTED TO EVOLVE FROM POSITIVELY TILTED TO
NEGATIVELY TILTED INTO SUNDAY WHICH WILL MAINTAIN INFLUENCE
FROM THIS TROUGH ACROSS THE GREAT LAKES THROUGH THE DAY. LOW
LEVEL COLD ADVECTION WILL INCREASE, ESPECIALLY THIS EVENING INTO
THE OVERNIGHT. THIS WILL ALLOW FOR INCREASE IN POTENTIAL OF
LIGHT SYSTEM SNOW TO BE ACCOMPANIED BY SOME LAKE ENHANCEMENT
INTO SUNDAY MORNING. STRONGER SYNOPTIC FORCING SHOULD BE
DISPLACED SOUTH AND EAST OF THE LOCAL AREA, SO ONLY LIGHT SNOW
AMOUNTS ARE EXPECTED TONIGHT INTO SUNDAY (GENERALLY 1-3") AS
LAKE ENHANCEMENT WILL BE SOMEWHAT LIMITED BY MODEST LAKE INDUCED
INSTABILITY DEPTHS. PERHAPS SOME COMPENSATION TO SOUTHWARD
DISPLACED SYNOPTIC FORCING FOR SOME SYSTEM SNOW WILL BE
SOUTHWESTWARD SAGGING LOW LEVEL BAROCLINIC ZONE TONIGHT ARISING
FROM COLLECTIVE WARMING INFLUENCE OF GREAT LAKES. THIS SHOULD
YIELD A FEW AXES OF LOW LEVEL FGEN FORCING AS THIS MODIFIED LOW
LEVEL AIR ENCOUNTERS COLDER AIR ADVECTING IN ACROSS THE WESTERN
GREAT LAKES. OTHERWISE, IT WILL BECOME WINDY FOR SUNDAY WITH
AFTERNOON GUSTS INTO THE 25 TO 35 MPH RANGE. TEMPS SHOULD LEVEL
OUT FOR THE PM HOURS OR PERHAPS DROP A FEW DEGREES.
ALL INDICATIONS STILL POINT TO THE SUNDAY EVENING INTO MONDAY
MORNING FOR THE POTENTIAL GREATER IMPACTS WITH LAKE EFFECT SNOW.
FLOW BECOMES MORE MERIDIONAL IN NATURE WITH BETTER LAKE TO LAKE
SUPERIOR CONNECTION. STRONGER LOW LEVEL COLD ADVECTION SUNDAY NIGHT
INTO EARLY MONDAY SHOULD SHARPEN LAKE AGGREGATE TROUGHING WITH AT
LEAST A POTENTIAL OF A MORE DOMINANT BAND SETTING UP THIS PERIOD.
HREF PROBS SUGGEST A BETTER POTENTIAL (ALBEIT LOW POTENTIAL) OF
SNOWFALL RATES GREATER THAN 1" PER HOUR SUNDAY NIGHT. WITH AN
INITIAL PHASE OF LIGHT SNOW LATE TONIGHT INTO SUNDAY, FOLLOWED BY
POTENTIALLY MORE IMPACTFUL PERIOD SUNDAY NIGHT/EARLY MONDAY, OPTED
TO HOIST A WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH MONDAY
EARLY AFTERNOON WITH EMPHASIS ON 2ND HALF OF THIS EVENT FOR
GREATER IMPACT POTENTIAL.
LOW LEVEL RIDGE AXIS QUICKLY TRACKS ACROSS THE AREA MONDAY NIGHT
SETTING UP A STRONGER SOUTHERLY RETURN FLOW SITUATION FOR TUESDAY,
AND A RETURN OF WINDY CONDITIONS. A RATHER INTERESTING SYNOPTIC
SETUP LOOKS TO BE IN STORE FOR THE WEDNESDAY-THURSDAY PERIOD. A CUT-
OFF NEGATIVE UPPER HEIGHT ANOMALY OFF PACIFIC NORTHWEST COAST, LOOKS
TO EJECT IN A COUPLE OF DIFFERENT PIECES INTO PRIMARY
WESTERLIES. THE FIRST OF THESE WAVES LOOKS TO EJECT NORTH OF THE
AREA LIKELY DRIVING A FRONTAL BOUNDARY SOUTHWARD ACROSS THE
SOUTHERN GREAT LAKES. THE 2ND OF THESE POTENTIAL DISTURBANCES
WILL BE ONE TO WATCH FOR LATE WEDNESDAY INTO THURSDAY.
PREDICTABILITY IN THIS TYPE OF SYNOPTIC PATTERN REGARDING EXACT
TRACK/DEPTH IS ON THE LOW SIDE, BUT THERE SHOULD BE A PRE-
EXISTING STRONG FRONTAL BOUNDARY IN PLACE FROM PREVIOUS 2 DAY
SYNOPTIC EVOLUTION. BLENDED POPS HAVE NUDGED UPWARD THIS CYCLE
LATE WEDNESDAY INTO THURSDAY WHICH APPEARS REASONABLE.
LOOKING AHEAD TO LATE WEEK AND NEXT WEEKEND, SOME MODERATION IN
TEMPS IS LIKELY BUT LOCAL AREA COULD BE PRONE TO ADDITIONAL SHOTS OF
COLD AIR TOWARD END OF THIS PERIOD GIVEN LOW LEVEL BAROCLINIC ZONE
WILL NOT BE LOCATED TOO FAR NORTH OF THE LOCAL AREA VIA
MAINTENANCE OF LONGWAVE EASTERN PACIFIC RIDGING.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1246 PM EST SAT FEB 21 2026
A PERIOD OF LIGHT SNOW WILL OVERSPREAD THE AREA AFTER 00Z, FIRST
AT KSBN AND LATER TONIGHT AT KFWA. MVFR CONDITIONS DUE TO CIGS
ARE ALREADY ONGOING AND WILL PERSIST INTO THE OVERNIGHT HOURS
WITH A TRANSITION TO LOW END MVFR AND EVEN IFR CIGS/VSBYS NEAR
OR AFTER 12Z SUN. SOME FINE TUNING WILL BE NEEDED IN COMING
ISSUANCES.
IWX WATCHES/WARNINGS/ADVISORIES
IN...WINTER WEATHER ADVISORY FROM 1 AM EST /MIDNIGHT CST/ SUNDAY TO
1 PM EST /NOON CST/ MONDAY FOR INZ103-104-203-204.
OH...NONE.
MI...WINTER WEATHER ADVISORY FROM 1 AM SUNDAY TO 1 PM EST MONDAY
FOR MIZ078-177-277.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...FISHER
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