694
FXUS63 KIWX 182336
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
636 PM EST THU DEC 18 2025
KEY MESSAGES
- WINDY AT TIMES THROUGH FRIDAY. WINDS: 20 TO 30 MPH WITH GUSTS TO
45. STRONGEST WINDS WITH THE FRONT AND JUST BEHIND THE FRONT.
- NUMEROUS SHOWERS INTO EARLY TONIGHT. RAINFALL AMOUNTS < 1". NO
FLOODING.
- FLASH FREEZE 8PM (WEST OF I-69) TO 2AM (EAST OF I-69). SOME
SECONDARY ROADS MAY BECOME ICY IN SPOTS.
- MILD AND MAINLY DRY TUESDAY THROUGH CHRISTMAS. HIGHS IN THE
40S TO LOWER 50S.
DISCUSSION
ISSUED AT 1208 PM EST THU DEC 18 2025
MILD AIR HAS SPREAD NORTH ACROSS THE ENTIRE FORECAST AREA WITH
TEMPERATURES IN THE 40S AND 50S. BANDS OF SHOWERS WILL CONTINUE TO
DEVELOP THIS AFTERNOON OVER AND TO THE WEST OF THE FORECAST AREA.
THESE SHOWERS WERE ASSOCIATED WITH A DEEP 986MB LOW OVER THE
ARROWHEAD REGION OF MN (FAR NORTHEAST MN). FORECAST CHALLENGES
INCLUDE TIMING OF THE COLD FRONT, TYPE IF ANY WIND HEADLINES,
ANY WINTRY MIX OF PRECIPITATION AND THE POTENTIAL FOR A FLASH
FREEZE. THE COLD AIR UPSTREAM HAS BEEN LAGGING SOMEWHAT BEHIND
THE SURFACE FRONT WHICH SHOULD HELP LIMIT ANY CHANCES FOR
FREEZING PRECIPITATION.
ALL INDICATIONS POINT TOWARD AN EVENT BELOW WIND ADVISORY CRITERIA.
THE STRONGEST WIND GUSTS SHOULD BE FROM THE WEST AT 20 TO 30 MPH
WITH GUSTS TO 45 MPH, ESPECIALLY WITH THE PASSAGE OF THE FRONT. DO
NOT PLAN TO ISSUE A WIND ADVISORY, BUT RATHER HANDLE THIS EVENT WITH
AN SPECIAL WEATHER STATEMENT AS THE FRONT NEARS. ONGOING UPSTREAM
OBSERVATIONS AND GFS LAMP GUIDANCE SUPPORT THE ABOVE. LOWS TONIGHT
ARE EXPECTED TO FALL INTO THE TEENS WITH HIGHS FRIDAY ONLY AROUND
25. THE LATEST TIMING FOR THE COLD FRONT IS AROUND MIDNIGHT EST
AT SOUTH BEND AND ABOUT 2AM EST OVER NORTHWEST OHIO.
UPSTREAM TELECONNECTIONS STRONGLY FAVOR A BRIEF INTRUSION OF
COLD AIR FOLLOWED BY MILD AIR RAPIDLY RETURNING TO THE AREA.
HIGHS FRIDAY SHOULD BE NEAR 25 - BUT HIGHS SATURDAY SHOULD BE
15 TO 20 DEGREES WARMER (LOWER 40S). AFTER A BRIEF ARCTIC
INTRUSION SUNDAY, THE MILD PATTERN WILL RETURN WITH A VENGEANCE.
THE LATEST GFS SHOWS BASICALLY A HIGHLY BLOCKED PATTERN IN THE
HIGH LATITUDES WITH UPPER RIDGES OVER THE ALEUTIAN ISLANDS,
CENTRAL AND EAST CONUS, AND OVER ICELAND. THE GFS 500 MB HEIGHT
ANOMALY IS VERY INDICATIVE OF THIS MILD PATTERN WITH BLOCKS
EXCEEDING 400 METERS (PER GFS OVER ALASKA AND ICELAND).
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 623 PM EST THU DEC 18 2025
COUPLE OF COLD FRONTAL BOUNDARIES WILL MOVE THROUGH OVER THE
NEXT SEVERAL HOURS. CURRENTLY, THE FIRST BOUNDARY IS MOVING
THROUGH THE AREA AND IS ASSOCIATED WITH A BAND OF CONVECTIVE
SHOWERS AND GUSTY SOUTHERLY WINDS. THE MAIN BOUNDARY THAT WILL
USHER IN MUCH COLDER AIR WILL BEGIN TO PUSH THROUGH AFTER 23Z
THU. EXPECTATION IS FOR MVFR CIGS TO CONTINUE THROUGH THE
REMAINDER OF THIS TAF PERIOD FOR BOTH SITES, HOWEVER THERE WILL
BE PERIODS OF SOME VSBY REDUCTIONS INTO IFR CATS DUE TO SNOW
SHOWERS AND MIST FOR BOTH SITES. FOR KFWA BETWEEN 01Z AND 04Z
FRI WITH MODERATE TO LIGHT RAINFALL AND MIST AND FOR KSBN BETWEEN
08Z AND 14Z FRI DUE TO LIGHT SNOWSHOWERS AND MIST. GUSTY WINDS
WILL ALSO CONTINUE THROUGH THE TAF PERIOD WITH SOUTHERLY WINDS
VEERING MORE WESTERLY AFTER ABOUT 01Z TO 03Z WITH THE INCREASED
CAA. GUSTS UP TO 35 KTS WILL BE POSSIBLE WITH SOME LOW LEVEL
WIND SHEAR EARLY ON ESPECIALLY FOR KFWA WITH THIS CONVECTIVE
SHOWER BOUNDARY PUSHING THROUGH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...GALE WARNING UNTIL 1 PM EST FRIDAY FOR LMZ043-046.
DISCUSSION...SKIPPER
AVIATION...ANDERSEN/STEINWEDEL
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