013
FXUS63 KIWX 172325
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
625 PM EST MON FEB 17 2025
KEY MESSAGES
- VERY COLD CONDITIONS WILL PERSIST THROUGH THE WEEK WITH HIGHS
IN THE TEENS TO LOWER 20S AND OVERNIGHT LOWS MAINLY IN THE
SINGLE DIGITS TO LOWER TEENS.
- SNOW ACCUMULATION CHANCES THIS WEEK EXIST MAINLY DUE TO LAKE
EFFECT TONIGHT INTO TUESDAY AND WEDNESDAY NIGHT INTO AT LEAST
THURSDAY.
- TEMPERATURES TRENDING BACK ABOVE FREEZING BY THE END OF THE
UPCOMING WEEKEND.
DISCUSSION
ISSUED AT 214 PM EST MON FEB 17 2025
WESTERLY FETCH ACROSS LK MI HAS KEPT THE BULK OF THE LES ACTIVITY
NORTH OF OUR AREA TODAY. OBSERVATIONS ACROSS FAR SOUTHERN LOWER MI
INDICATED SOME LIGHT SNOW AND VSBY RESTRICTS (ESPECIALLY AT KBEH)
THIS MORNING MOST LIKELY DUE TO BLOWING SNOW (GUSTS 25 TO 30 KTS)
AND ALSO FINE NATURE OF THE SNOW. FETCH WILL BEGIN TO MORE NW
OVERNIGHT INTO TUESDAY AND THEN NNW TUE NIGHT INTO WED AS A
COMBINATION OF A WEAK MID LEVEL TROUGH PUSHES SOUTH AND OVERALL FLOW
BEGINS TO ADJUST IN RESPONSE TO A DEEPER UPPER LOW. DGZ IS IN THE
LOWEST LAYERS AS IS THE BEST LIFT. HOWEVER, A DRY SUB LAYER STILL
EXISTS WITH INVERSION HEIGHTS 4K TO 5KFT AND EQUILIBRIUM LEVELS
5K TO 6KFT. FORECAST GENERALLY ON TRACK WITH CHANCES FOR SNOW
SHOWERS SHIFTING BACK INTO FAVORED NW FLOW COUNTIES. OVERALL
FLOW NOT THAT STRONG SO NOT ANTICIPATING MUCH INLAND
PENETRATION. OVERALL SETUP APPEARS TO BE MULTI BAND VS SINGLE AS
CONVERGENCE IS RATHER LIMITED. MAY BE SOME SUBTLE INDICATIONS
TUESDAY AFTERNOON FOR SOME INCREASED CONVERGENCE THAT COULD
YIELD 1 OR 2 SOMEWHAT STRONGER BANDS. FOR NOW, ACCUMULATIONS
SHOULD BE MINOR (1" OR LESS). THE SNOW SHOWERS MAY LINGER INTO
EARLY WEDNESDAY, MAINLY OVER LAPORTE COUNTY BUT LITTLE IF ANY
ACCUMULATION IS EXPECTED.
DEEPENING UPPER LOW IS STILL SET TO RAPIDLY PASS ACROSS THE AREA WED
NIGHT INTO THURSDAY. MODEL SIGNALS STILL THERE FOR A TOUCH OF LIGHT
SNOW WEDNESDAY AFTERNOON THAT MIGHT BRING A FEW TENTHS OF SNOW TO
THE AREA. SOMEWHAT GREATER CONCERN FOR A MORE PRONOUNCED LAKE
EFFECT BAND SETTING UP WED NIGHT INTO THURSDAY WITH 925 MB
STREAMLINES AND 850 MB OMEGA FIELDS ALL SUGGESTING STRONG
CONVERGENCE DOWN THE LONG (MAJOR) AXIS OF LAKE MI AS WELL AS A
CONNECTION TO LAKE SUPERIOR. THESE BANDS CAN BE PROLIFIC SNOW
PRODUCERS AND EXTEND WELL INLAND. A LOT OF DETAILS TO SORT OUT
IN THE COMING DAYS WITH FINAL TRACK OF UPPER LEVEL AND SFC
FEATURES ALL KEY TO THE FINAL ALIGNMENT OF THE BAND. ALSO,
UNLIKE THE CURRENT LES SETUP, THE DGZ WILL CLIMB TO A MORE
TYPICAL LEVEL AND MAY RESIDE NEAR THE TOP OF OR JUST ABOVE THE
BEST LIFT. ALSO, QUALITY/DEPTH OF THE MOISTURE MAY BE SOMEWHAT
LIMITED. POPS AND POTENTIAL SNOW AMOUNTS REMAIN VERY
CONSERVATIVE AT THIS POINT, BUT SOMETHING TO MONITOR.
TEMPERATURES WILL REMAIN WELL BELOW NORMAL MUCH OF THE UPCOMING WEEK
WITH INDICATIONS OF WARMER, CLOSER TO NORMAL LEVELS STILL ON TRACK
FOR LATE THIS WEEKEND INTO NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 616 PM EST MON FEB 17 2025
A VERY COLD BUT SHALLOW AIRMASS WAS OVER THE REGION. LAKE EFFECT
SNOW SHOWERS HAD A SHORT TRAJECTORY OVER LAKE MICHIGAN WITH A
280 FETCH. WINDS SHOULD VEER MORE TO THE NORTHWEST AND ALLOW A
MORE FAVORABLE FETCH TO DEVELOP WITH MORE FAVORABLE CONDITIONS
FOR SNOW SHOWERS AT SBN. FOR THIS TAF CYCLE AT SBN, WENT WITH
MVFR VISIBILITIES FOR AN EXTENDED PERIOD. IT IS LIKELY NARROW
BANDS OF HEAVIER SNOW WILL DEVELOP AND MAY LOWER VISIBILITIES
BELOW 3SM AT SBN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EST TUESDAY FOR LMZ043-046.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST TUESDAY FOR LMZ043-
046.
DISCUSSION...FISHER
AVIATION...SKIPPER
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