236
FXUS63 KIWX 200743
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
243 AM EST SAT DEC 20 2025
KEY MESSAGES
- BREEZY TODAY WITH SOUTHERLY WINDS GUSTS AS HIGH AS 30 TO 35
MPH. WINDS SHIFT TO BECOME WEST/NORTHWEST THIS EVENING AND
SLOWLY SUBSIDE THROUGH SUNDAY MORNING.
- NEXT CHANCE FOR RAIN/SNOW ARRIVES MONDAY AFTERNOON INTO TUESDAY.
ADDITIONAL RAIN CHANCES POSSIBLE AROUND CHRISTMAS.
- BRIEFLY COLDER ON SUNDAY WITH HIGHS IN THE UPPER 20S TO LOW
30S BEFORE A WARMING TREND ENSUES NEXT WEEK IN THE LEAD UP TO
CHRISTMAS. HIGH TEMPERATURES ON CHRISTMAS DAY WILL BE NEAR
RECORD LEVELS IN THE UPPER 50S TO LOW 60S!
DISCUSSION
ISSUED AT 243 AM EST SAT DEC 20 2025
A TIGHTENING PRESSURE GRADIENT BETWEEN HIGH PRESSURE CENTERED OVER
THE SOUTHEAST US AND A DEEPENING LOW PRESSURE OVER THE NORTHERN
PLAINS WILL MAKE FOR BREEZY CONDITIONS THROUGH THE EVENING. THE
TRICKIEST PART OF THE FORECAST FOR TODAY IS REGARDING HOW MUCH
THE ATMOSPHERE MIXES OUT AND DESTABILIZES TODAY AHEAD OF AN
INCOMING COLD FRONT (SOUNDINGS SHOW A FAIRLY DEEP AND PERSISTENT
INVERSION NEAR THE SURFACE TODAY). A STRONG LOW LEVEL JET (60+
KT AT 850MB) COULD ALLOW FOR GUSTY SOUTHERLY WINDS TO MIX DOWN
TO THE SURFACE TODAY, ESPECIALLY THIS AFTERNOON AND EVENING. WAA
IS A TOUGHER ENVIRONMENT TO GET SUFFICIENT MIXING DOWN TO THE
SURFACE, SO GIVEN THIS UNCERTAINTY, HAVE STUCK WITH WIND GUSTS
AS HIGH AS 30 TO 35 MPH TODAY. ALTHOUGH, I WOULDN'T BE SURPRISED
IF SPORADIC HIGHER GUSTS ARE REALIZED. THE COLD FRONT COMES
THROUGH THIS EVENING; IT WILL BE A MAINLY DRY FRONT WITH THE
EXCEPTION BEING A FEW ISOLATED SHOWERS POSSIBLE NEAR LAKE
MICHIGAN IN SOUTHWEST LOWER MICHIGAN. ONCE THE FRONT IS THROUGH,
WINDS SHIFT TO BECOME WEST/NORTHWEST AND WILL GRADUALLY SUBSIDE
THROUGH SUNDAY MORNING. ANOTHER COLD NIGHT IS AHEAD AS LOWS
SUNDAY MORNING WILL BE AROUND 20 DEGREES WITH WIND CHILLS IN THE
SINGLE DIGITS TO LOW TEENS.
SUNDAY WILL BE A DRY DAY AS SURFACE HIGH PRESSURE BUILDS IN
OVERHEAD. THE NEXT CHANCES FOR RAIN/SNOW ARRIVE MONDAY AFTERNOON
THROUGH TUESDAY MORNING WITH A QUICK CLIPPER SYSTEM. WITH
TEMPERATURES LIKELY IN THE MID TO UPPER 30S WHEN THIS SYSTEM COMES
THROUGH, WE WILL HAVE TO WATCH THE PRECIPITATION TYPE CLOSELY. THE
GFS IS HINTING AT A POSSIBLE FREEZING DRIZZLE SETUP, HOWEVER, THE
NBM HAS A RAIN/SNOW MIX. A WARM FRONT COMES THROUGH OVERNIGHT MONDAY
INTO EARLY TUESDAY, SO IT IS ALSO POSSIBLE THAT THIS SETUP STARTS AS
FREEZING DRIZZLE AND TRANSITIONS TO JUST A COLD RAIN. DEPENDING ON
PAVEMENT TEMPERATURES, ROADS COULD BE SLICK FOR THE TUESDAY MORNING
COMMUTE.
FOR THOSE HOPING FOR A WHITE CHRISTMAS, UNFORTUNATELY, ALL OF THE
COLD AND SNOW WE EXPERIENCED DURING THE FIRST HALF DECEMBER DOES NOT
APPEAR TO BE RETURNING ANYTIME SOON. THERE IS HIGH CONFIDENCE THAT A
WARMING TREND IS AHEAD TO FINISH OUT THE LAST FULL WEEK OF DECEMBER.
A DOMINANT UPPER LEVEL RIDGE DEVELOPS ACROSS THE CENTRAL PLAINS AND
BRINGS ABOVE AVERAGE WARMTH ACROSS MUCH OF THE CONUS FOR CHRISTMAS.
FOR OUR AREA, NEAR RECORD HIGHS IN THE UPPER 50S TO LOW 60S APPEAR
LIKELY (ESPECIALLY SOUTH OF US 30) FOR CHRISTMAS. WITH ALL OF THIS
WARMTH COMES THE POTENTIAL FOR RAIN AROUND CHRISTMAS AS A LOW
PRESSURE SYSTEM COULD DEVELOP OVER THE GREAT LAKES. CHANCES FOR RAIN
AS OF NOW APPEAR HIGHEST OVERNIGHT CHRISTMAS EVE HEADING INTO EARLY
CHRISTMAS DAY. STAY TUNED!
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1255 AM EST SAT DEC 20 2025
VFR CONDITIONS ARE EXPECTED AT THE TERMINALS THIS PERIOD WITH
MAINLY LLWS AND MID-HIGH LEVEL CLOUDS TO CONTEND WITH. WARM AIR
ADVECTION UNDERWAY TODAY WITH A LLJ BRINGING IN STRONGER WINDS
ALOFT (60KTS). UNCERTAINTY EXISTS WITH REGARDS TO HOW MUCH
MIXING OCCURS TODAY (SUSPECT MORE STABLE GIVEN WAA AND CLOUDS),
SO PERHAPS A GUST UP TO AROUND 35 KNOTS IS POSSIBLE DURING THE
AFTERNOON HOURS. FOR NOW LIMITED TO AROUND 30 KNOTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
LMZ043-046.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ043-046.
DISCUSSION...JOHNSON
AVIATION...MCD
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