948
FXUS63 KIWX 201906
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
206 PM EST MON JAN 20 2025
KEY MESSAGES
- THE COLD WEATHER ADVISORY REMAINS IN EFFECT UNTIL 10 AM EST
WEDNESDAY AREA-WIDE. WIND CHILLS AS LOW AS 25 BELOW ZERO WILL
BE POSSIBLE TUESDAY MORNING, ESPECIALLY IN AN AREA BETWEEN
LAPORTE AND GOSHEN.
- ADDITIONAL LAKE EFFECT SNOW ACCUMULATIONS OF 1 TO 4 INCHES ARE
EXPECTED IN SOUTHWEST LOWER MICHIGAN. THE WINTER WEATHER
ADVISORY FOR BERRIEN AND CASS COUNTIES REMAINS IN EFFECT UNTIL
7 AM EST TUESDAY.
- MAINLY DRY WITH TEMPERATURES RETURNING TO AROUND NORMAL BY
THIS WEEKEND.
DISCUSSION
ISSUED AT 202 PM EST MON JAN 20 2025
AN INSTABILITY TROUGH SWINGS THROUGH INTO THIS EVENING. THE WARM
ADVECTION PERIOD OUT IN FRONT BUMPS SURFACE TEMPERATURES TO AROUND
10F DEGREES THIS AFTERNOON BEFORE TEMPERATURES START DROPPING THIS
EVENING. AN AREA OF COLD ADVECTION MOVES THROUGH TUESDAY MORNING AND
THEN WINDS CALM DOWN A FEW MPH DURING THE AFTERNOON SO THAT WINDS
TUESDAY ARE EXPECTED TO BE CALMER THAN TODAY'S WINDS. WITH THE
COOLER LOW LEVEL TEMPERATURES AND SOME WINDS TO WORK WITH, WIND
CHILLS MAY BE ABLE TO APPROACH -25F VALUES, ESPECIALLY IN AN AREA
BETWEEN LAPORTE AND ELKHART. ONE THING THAT BRINGS A LITTLE LESS
CONFIDENCE IS THE CLOUDS THAT MOVE THROUGH OVERNIGHT AND THE LACK OF
DECOUPLING ALLOWING FOR MINIMAL RADIATIONAL COOLING. AS SUCH, WILL
INCREASE THE RANGE OF POSSIBLE WIND CHILLS, BUT STILL THINK MUCH OF
THE AREA REMAINS BELOW WARNING THRESHOLD. WINDS THEN PICK UP ON
WEDNESDAY AS THE TROUGH VACATES THE AREA AND WARM ADVECTION ENSUES.
MID/UPPER CLOUD COVER LOOKS TO APPROACH THE AREA TOWARDS THE LATTER
PORTION OF THE NIGHT TUESDAY NIGHT. ONE OUTCOME THAT IS POSSIBLE FOR
TEMPERATURES IS THAT THEY DROP TUESDAY EVENING AND THEN LEVEL OUT
FOR THE REST OF THE NIGHT. AFTER THE FINAL CHANCE FOR COLD WEATHER
ADVISORY WIND CHILLS WEDNESDAY MORNING, TEMPERATURES ARE ABLE
TO WARM BACK INTO THE TEENS AND LOW 20S ABOVE ZERO ON WEDNESDAY.
THE BEST CHANCE SEE US TICK BACK ABOVE FREEZING IS THIS
WEEKEND.
AS FOR LAKE EFFECT SNOW, GENERALLY WEST WINDS TODAY BECOME
SOUTHWESTERLY BY LATER TUESDAY. THE BEST COLUMNAR MOISTURE MOVES
THROUGH THIS EVENING BEFORE A SLOW DISSIPATION OF MOISTURE OCCURS UP
TO AROUND 00Z TUESDAY EVENING, WHICH IS ALSO WHEN NEGATIVE THETA-E
LAPSE RATES PUSH NORTHWARD. INVERSION HEIGHTS RISE BACK TO ABOVE
7000 FT THIS EVENING BEFORE SLOWLY FALLING BACK BELOW 6000 FT
TUESDAY AFTERNOON. GIVEN THESE PARAMETERS, AM FINE HOLDING WITH THE
CURRENT EXPIRATION TIMES AND LOCATIONS FOR THE WINTER WEATHER
ADVISORY.
FOR THIS EVENING INTO TONIGHT, THE AREA OF WARM ADVECTION WITH THE
DGZ ESSENTIALLY IN THE GROUND SHOULD ALLOW FOR A PERIOD OF FLURRIES
OR LIGHT SNOW SHOWERS TO MOVE THROUGH SOUTH OF US-6 TONIGHT INTO
EARLY TUESDAY MORNING, WHEN IT'S VACATING OUR OH COUNTIES. MODEL
TIME SECTIONS INDICATE AN AREA OF OMEGA AROUND 6Z BETWEEN MONTICELLO
AND MIAMI COUNTY, BUT THIS OMEGA SIGNATURE DROPS OFF IN THE I-69
CORRIDOR. THIS AMOUNT OF OMEGA IN THAT WESTERN AREA MAY BE ENOUGH TO
CAUSE BRIEF VISIBILITY REDUCTIONS.
ANOTHER OPPORTUNITY FOR SNOW ARRIVES THURSDAY AS A FRONTAL
SYSTEM MOVES THROUGH. GIVEN THE FRONTAL FORCING AND WITH SOME
MOISTURE ISSUES, WILL CONTINUE WITH ISOLATED TO SCATTERED POPS.
THERE HAS BEEN SOME SIGNAL FOR A SYSTEM TO MOVE THROUGH DURING
THE WEEKEND, BUT THE HANDLING OF THE WAVE SHEARING OUT INTO THE
SOUTHWEST AND THE UPPER RIDGE IN THE SOUTHEAST MAY RESTRICT THE
SOUTHWARD EXTENT OF PRECIPITATION INTO THIS AREA.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1149 AM EST MON JAN 20 2025
WINDS HAVE BACKED ENOUGH OVER NORTHWEST INDIANA TO ALLOW LAKE
CLOUDS AND SNOW SHOWERS TO MOVE NORTH OF THE SBN TERMINAL. TO
THE SOUTH, A LARGE HIGH PRESSURE AREA HAD SETTLED OVER KY. THE
FLOW NORTH OF THIS SYSTEM WAS KEEPING BRISK WINDS OVER NORTHERN
INDIANA. WINDS SOUTHWEST TO WEST SHOULD PREVAIL THROUGH THE END
OF THE TAF PERIOD. THE AIRMASS APPEARS TOO DRY TO SUPPORT ANY
CLOUDS, SO HAVE KEPT VFR CONDITIONS WITH CLEAR SKIES AND
UNRESTRICTED VISIBILITIES.
IWX WATCHES/WARNINGS/ADVISORIES
IN...COLD WEATHER ADVISORY UNTIL 10 AM EST /9 AM CST/ WEDNESDAY FOR
INZ005>009-012>015-017-018-020-022>027-032>034-103-104-
116-203-204-216.
OH...COLD WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR OHZ001-002-
004-005-015-016-024-025.
MI...COLD WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR MIZ078>081-
177-277.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ078-177-
277.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-046.
HEAVY FREEZING SPRAY WARNING UNTIL 5 PM EST TUESDAY FOR LMZ043-
046.
DISCUSSION...ROLLER
AVIATION...SKIPPER
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