563
FXUS63 KIWX 151822
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
122 PM EST MON DEC 15 2025
KEY MESSAGES
- MODERATING TEMPERATURES AND BREEZY AT TIMES THROUGH THURSDAY.
- PERIODS OF RAIN LATE WEDNESDAY NIGHT INTO THURSDAY, POSSIBLY
MIXING OR ENDING AS SNOW SHOWERS THURSDAY NIGHT INTO FRIDAY.
- WINDY AND BRIEFLY COLDER CONDITIONS ON FRIDAY.
DISCUSSION
ISSUED AT 122 PM EST MON DEC 15 2025
WARMING TEMPS REMAIN THE STORY THROUGH THURSDAY AS PACIFIC AIR
FLOODS THE LOWER 48 UNDER A MORE PROGRESSIVE, QUASI-ZONAL, FLOW
REGIME. SEVERAL SHORTWAVES WILL TRACK EAST WITHIN THIS FLOW, WITH A
TUESDAY NIGHT IMPULSE THROUGH THE NORTHERN GREAT LAKES SENDING A
WEAKENING FRONT INTO THE AREA EARLY WEDNESDAY. HEIGHT FALLS AND
ASCENT WITH THE UPPER WAVE DOES CLIP THE AREA, THOUGH MOST OF THIS
FORCING WILL GO TO MID-UPPER LEVEL SATURATION WITH A DRY FORECAST
RETAINED GIVEN A NOTABLE DRY LAYER BELOW ROUGHLY 700 MB.
THE NEXT PACIFIC WAVE WILL BE MUCH MORE AMPLIFIED ENCOURAGING
CYCLOGENESIS EAST THROUGH THE NORTHERN GREAT LAKES THURSDAY
INTO THURSDAY NIGHT. THIS WILL DRAW SOME GULF MOISTURE NORTHWARD
WITH PERIODS OF RAIN ANTICIPATED ALONG AND IN ADVANCE OF A
TRAILING COLD FRONT DURING THE DAY ON THURSDAY. A BRIEF SHOT OF
GUSTY WINDS AND CHANCES FOR SNOW SHOWERS THEN SWING THROUGH ON
THE BACKSIDE OF THE LOW INTO THURSDAY NIGHT AND FRIDAY.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1150 AM EST MON DEC 15 2025
A STRONG WARM ADVECTION PATTERN IS UNDERWAY ACROSS NORTHERN
INDIANA LATE THIS MORNING. WHILE SFC WINDS HAVE BEEN STEADILY
INCREASING, GUSTS OF 20+ KNOTS HAVE BEEN SHORT-LIVED TO THIS
POINT. THESE SOUTHWEST WINDS ARE COMING FROM AN AREA WITH AN
EXTENSIVE SNOWPACK, SO LOW LEVEL MIXING IS TAKING SOME TIME TO
MATERIALIZE. OVER NEXT HOUR OR TWO WOULD EXPECT GUSTS TO BECOME
MORE FREQUENT IN THE 20 TO 25 KNOT RANGE AT THE TERMINALS. A
WEAKENING LOW LEVEL GRADIENT AND LOSS OF DAYTIME MIXING SHOULD
SLACKEN WINDS SHARPLY AFTER 22Z. ANOTHER SFC LOW ASSOCIATED WITH
A NORTHERN STREAM SHORT WAVE SHOULD TRACK ACROSS SOUTH CENTRAL
CANADA ON TUESDAY, WITH MAIN EFFECT FOR LOCAL AREA TO SLIGHTLY
INCREASE SOUTHWESTERLY GRADIENT ONCE AGAIN. IN TERMS OF CLOUDS,
SOME INCREASED LOW LEVEL MOISTURE SHOULD DROP SOUTHEAST FROM THE
WESTERN GREAT LAKES THIS EVENING IN ASSOCIATION WITH WARM FRONT,
BUT GREATER CONFIDENCE IN MVFR CIGS STILL APPEARS TO BE NORTH OF
THE TERMINALS ACROSS MICHIGAN AND WILL MAINTAIN VFR FORECAST.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
DISCUSSION...STEINWEDEL
AVIATION...MARSILI
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