467
FXUS63 KIWX 190554
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1254 AM EST WED FEB 19 2025
KEY MESSAGES
- SCATTERED, LIGHT, LAKE EFFECT SNOW SHOWERS AND FLURRIES WILL
CONTINUE INTO TONIGHT AND WEDNESDAY NEAR LAKE MICHIGAN. AN
ADDITIONAL DUSTING TO 1 INCH POSSIBLE.
- A PERIOD OF LIGHT SYSTEM SNOW EXPECTED WEDNESDAY NIGHT INTO EARLY
THURSDAY MORNING. ACCUMULATIONS UP TO 1" POSSIBLE.
- LAKE EFFECT SNOW EXPECTED LATE WEDNESDAY NIGHT INTO THURSDAY
IN NORTHWEST FLOW PRONE AREAS DOWNWIND OF LAKE MICHIGAN.
DIFFICULT TRAVEL POSSIBLE IN THESE AREAS.
DISCUSSION
ISSUED AT 235 PM EST TUE FEB 18 2025
COLD NORTHWEST FLOW WILL KEEP SCATTERED LAKE EFFECT SNOW
SHOWERS/FLURRIES IN THE FORECAST NEAR LAKE MI INTO TONIGHT AND
WEDNESDAY, THOUGH GENERALLY CONSTRICTING MORE TO THE IMMEDIATE
SHORELINE WITH TIME AS LOW LEVEL FLOW TRAJECTORIES DIMINISH. THE
DRY NATURE TO THIS AIR MASS, AND THE RESULTING SHALLOW/WEAK
SATURATION NEAR THE TOP (OR JUST ABOVE) THE DGZ, LIKELY KEEPS
ADDITIONAL ACCUMS ON THE LIGHT SIDE (DUSTING-1"). NOT AS COLD
WITH LIGHTER WINDS OTHERWISE INTO TONIGHT THANKS TO LINGERING
LAKE CLOUDS, AND AN INCREASE IN MID-HIGH LEVEL CLOUD COVER ON
THE NORTHERN FRINGE OF A TN/OH VALLEY STORM SYSTEM.
AN UPPER LEVEL LOW WILL PIVOT THROUGH LATE WEDNESDAY AFTERNOON INTO
EARLY THURSDAY MORNING WITH INCREASING CONFIDENCE IN A PERIOD OF
LIGHT SYSTEM SNOW. DECENT MID-UPPER LEVEL QG ASCENT WILL ACCOMPANY
THIS WAVE OVER STEEPENING LOW LEVEL LAPSE RATES SUPPORTIVE OF
A PERIOD OF SNOW, THOUGH THE OVERALL DEARTH OF MOISTURE LIKELY
KEEPS A LID ON ACCUMS (GENERALLY A HALF INCH TO INCH, STICKING
ON UNTREATED PAVEMENT GIVEN CHILLY TEMPS).
THE LAKE RESPONSE HAS THE POTENTIAL TO STACK UP SOME SNOW IN FAVORED
NW FLOW SNOW BELTS LATE WEDNESDAY NIGHT INTO THURSDAY IN WAKE OF THE
UPPER LOW. PROS INCLUDE A LAKE SUPERIOR CONNECTION, 700 MB DELTA T'S
PUSHING THE MID 20S, LAKE INDUCED INVERSION HEIGHTS TOPPING OUT
AT 8-10 KFT, SYNOPTIC SCALE SEEDING, GOOD SATURATION WITH RESPECT
TO ICE WITHIN THE CLOUD LAYER RESIDING IN PORTION OF THE DGZ,
AND SIGNALS OF LAKE AGGREGATE THERMAL TROUGHING/CONVERGENCE
EMERGING DURING THIS TIME FOR A MORE SIGNIFICANT BANDING
POTENTIAL. BERRIEN/NRN LAPORTE/ST JOE IN/ELKHART/CASS MI ARE ALL
IN PLAY FOR HEADLINE LEVEL SNOW/IMPACTS, WITH SOME POTENTIAL
FOR IMPACTS FARTHER SOUTH TOWARD THE US 30 CORRIDOR IN IN ON
THURSDAY GIVEN POTENTIAL SEEDING AND INCREASED FLOW. THERE
REMAIN LINGERING UNCERTAINTIES HOWEVER REGARDING FLOW
TRAJECTORIES AND MOISTURE QUALITY THAT WILL ULTIMATELY DICTATE
WHERE MORE ORGANIZED LE BANDING SETS UP DURING THIS TIME.
SOMETHING TO MONITOR GOING FORWARD.
THE PATTERN FRIDAY THROUGH EARLY NEXT WEEK THEN FAVORS A WELCOMED
TREND TOWARD MILDER (NEAR NORMAL) TEMPERATURES GIVEN A TRANSITION TO
A MORE MODIFIED WEST-NORTHWEST FLOW REGIME.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1249 AM EST WED FEB 19 2025
LAKE EFFECT SNOW SHOWERS ARE EXPECTED TO PERSIST OVERNIGHT WITH
OCCASIONAL MVFR VSBYS/CIGS AT KSBN. A LEAD SHORT WAVE IN
SOUTHWEST UPPER FLOW IN ADVANCE OF LARGER SCALE UPPER TROUGH
ACROSS CENTRAL CONUS MAY ENHANCED LAKE EFFECT SNOW SHOWERS LATE
MORNING INTO MID AFTERNOON AT KSBN WITH A PERIOD OF IFR VSBYS
POSSIBLE AT TIMES. THE PRIMARY UPPER LEVEL TROUGH WILL KICK
EASTWARD TONIGHT PROVIDING BOTH SYSTEM SNOW TO NORTHERN INDIANA
AND A PERIOD OF POTENTIALLY MORE ROBUST LAKE EFFECT SNOW
SHOWERS. CURRENT THINKING IS THE HEAVIEST LAKE EFFECT SNOW
SHOWERS AT KSBN WILL BE TOWARD END OF THIS FORECAST VALID PERIOD
AND INTO EARLY THURSDAY MORNING. SYSTEM SNOW IS ALSO EXPECTED TO
OVERSPREAD TERMINALS IN THE EVENING HOURS WITH IFR VSBYS
POSSIBLE. ACCUMULATIONS AROUND AN INCH ARE POSSIBLE AT KFWA WITH
THIS SYSTEM, ALTHOUGH WILL NEED TO MONITOR FOR POTENTIAL OF SOME
LOCALIZED BANDING BRINGING LOCALLY HIGHER AMOUNTS TO NE INDIANA.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...STEINWEDEL
AVIATION...MARSILI
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