384
FXUS63 KIWX 131852
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
152 PM EST MON JAN 13 2025
KEY MESSAGES
- REMAINING COLD THROUGH MID WEEK WITH TIMES OF BELOW ZERO WIND CHILLS
OUTSIDE OF LAKE EFFECT CLOUDS.
- SCATTERED TO NUMEROUS LAKE EFFECT SNOW SHOWERS CONTINUE
TONIGHT THROUGH TUESDAY NIGHT, MAINLY ALONG AND NORTH OF THE
TOLL ROAD. LIGHT ACCUMULATIONS AND SLIPPERY TRAVEL POSSIBLE,
ESPECIALLY LATE TONIGHT INTO TUESDAY.
- A PERIOD OF LIGHT SYSTEM SNOW TUESDAY MORNING INTO EARLY
TUESDAY AFTERNOON, BEST CHANCES (60-70%) SOUTH OF US 30 IN
INDIANA WHERE SLIPPERY TRAVEL WILL BE POSSIBLE.
- A BRIEF THAW BY FRIDAY WITH TEMPERATURES ABOVE FREEZING.
- ANOTHER PUSH OF ARCTIC AIR EXPECTED BY EARLY NEXT WEEK, LIKELY
THE COLDEST OF THE WINTER SEASON SO FAR.
DISCUSSION
ISSUED AT 152 PM EST MON JAN 13 2025
VORT LOBE OVER NORTHERN MN WILL OPEN SOUTHEAST THROUGH THE LOWER
GREAT LAKES LATE TONIGHT INTO TUESDAY BRINGING A REINFORCING SHOT OF
COLD AIR AND SNOW CHANCES. STRONG DCVA, CAA, AND A BRIEF INCREASE
TO INVERSION HEIGHTS SHOULD INVIGORATE THE LAKE RESPONSE ON
TUESDAY IN WNW FLOW LAKE BELTS. A SUBTLE IMPULSE UNDERCUTTING
THE INCOMING TROUGH WILL ALSO ALLOW A NARROW BAND OF SYNOPTIC
SCALE SNOW TO TRACK QUICKLY ACROSS CENTRAL IL/IN WITH UP TO AN
INCH OF FLUFFY SNOW IN THIS COLD REGIME (HIGH SLR ENVIRONMENT).
THIS ACTIVITY COULD CLIP AREAS MAINLY SOUTH OF US 30 IN IN MID
MORNING THROUGH EARLY AFTERNOON, WITH AT LEAST SCATTERED SNOW
SHOWERS/FLURRIES AROUND FOR THE ENTIRE AREA DURING THE DAY
GIVEN THE PASSAGE OF THE UPPER TROUGH AND FURTHER INLAND PUSH OF
THE LAKE MODIFIED BOUNDARY LAYER. OVERALL DRY NATURE TO THIS
AIRMASS WILL LIMIT ACCUMS, BUT STILL COULD SEE SOME MINOR TRAVEL
DISRUPTIONS, ESPECIALLY CLOSER TO LAKE MI.
TIMES OF BELOW ZERO WIND CHILLS OUTSIDE THE LAKE PLUME THROUGH THE
MIDDLE OF THE WEEK WILL GIVE WAY TO A BRIEF WARMING TREND THURSDAY
INTO FRIDAY AS MID LEVEL HEIGHTS REBOUND AND LOW LEVEL WINDS BACK
SOUTHWESTERLY BY FRIDAY. MAINLY DRY AS WELL DURING THESE PERIODS
WITH LATEST GUIDANCE IN DECENT AGREEMENT IN A CLIPPER SYSTEM
MAINLY MISSING TO THE NORTHEAST ON THURSDAY.
ANOTHER ROUND OF ARCTIC AIR, LIKELY THE COLDEST OF THE WINTER
SEASON, APPEARS LIKELY BY EARLY NEXT WEEK AS AN EXPANSIVE UPPER
LEVEL TROUGH RETURNS IN RESPONSE TO RENEWED RIDGING OVER THE GULF OF
ALASKA. ENSEMBLES DEFINITELY AGREE ON THIS EVOLUTION WITH 50-70%
PROBS FOR ADVISORY LEVEL WIND CHILLS (<=-15F) AT SOME POINT DURING
THIS STRETCH. A BAROCLINIC WAVE TRACKS THROUGH IN THIS TRANSITION
WITH CHANCES (40-60%) FOR RAIN AND SNOW FRIDAY NIGHT INTO SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1216 PM EST MON JAN 13 2025
GENERAL MVFR FLIGHT RULE THIS PERIOD. LAKE STRATOCU PLUME
PERSISTS OFF LAKE MICHIGAN INVOF KSBN AND JUST ENOUGH MOISTURE
DEPTH WITHIN SHALLOW POST ARCTIC BOUNDARY TO SUPPORT LIGHT SNOW
WHICH SHOULD PERSIST FOR ANOTHER HOUR OR TWO BEFORE MORE
VIGOROUS DRY ENTRAINMENT OCCURS. OTHERWISE VEERING TO WRLY LOW
LEVEL FLOW THROUGH THIS AFTN EXPECTED TO ALLOW LAKE CLOUD PLUME
TO EDGE SOUTH FOR A TIME INTO THE KFWA VCNTY LATE DAY.
UPSTREAM DISTURBANCE OVER NRN MN WILL SWING ACROSS THE TERMINALS
TUE MORNING WITH A PERIOD OF LIGHT SNOW AND IFR CONDITIONS FOR A
TIME. SOME UNCERTAINTY/SPREAD IN ARRIVAL TIME AND GIVEN LATE
PERIOD TIMING WILL AWAIT LATER GUIDANCE BEFORE INCLUSION.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR LMZ043-046.
DISCUSSION...STEINWEDEL
AVIATION...T
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