602
FXUS63 KIND 161629
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1129 AM EST TUE DEC 16 2025
KEY MESSAGES
- WIDESPREAD MODERATE RAIN LIKELY THURSDAY WITH MINOR FLOODING
POSSIBLE.
- GUSTY WINDS THURSDAY EVENING/NIGHT.
- FLASH FREEZE THREAT THURSDAY NIGHT/EARLY FRIDAY AS TEMPERATURES
COULD FALL 30 DEGREES IN 12 HRS.
- ABOVE NORMAL TEMPERATURES EXPECTED NEXT WEEKEND INTO CHRISTMAS
WEEK.
FORECAST UPDATE
ISSUED AT 1127 AM EST TUE DEC 16 2025
SOME ADJUSTMENTS WERE MADE TO THE FORECAST TODAY. FIRST WAS
TEMPERATURES THIS MORNING AS IT HAS WARMED SLIGHTLY FASTER THAN
FORECASTED. HOWEVER STILL EXPECTING HIGHS IN THE MID 30S TO LOW 40S
THIS AFTERNOON. HAVE ALSO REMOVED THE FREEZING DRIZZLE/ DRIZZLE
MENTION FROM THE GRIDS THIS EVENING AS CONFIDENCE HAS LOWERED AND
LOOKING MORE LIKELY IT'LL BE DRY ENOUGH THROUGH THE COLUMN. STILL
CAN'T SAY SOME LIGHT PRECIPITATION IS IMPOSSIBLE UNDER LOW CLOUDS SO
HAVE INSTEAD PUT IN SLIGHT CHANCE FOR SPRINKLES/FLURRIES THIS
EVENING.
SHORT TERM (TODAY AND TONIGHT)
ISSUED AT 246 AM EST TUE DEC 16 2025
A STRONG SURFACE LOW IS CURRENTLY MOVING EASTWARD OVER SOUTH CENTRAL
CANADA. SOUTHWESTERLY FLOW IS EXPECTED TO INCREASE AS THE SYSTEM
PASSES JUST NORTH OF LAKE SUPERIOR THIS AFTERNOON. WARM AIR
ADVECTION WILL BE PRESENT THROUGH THE DAY TODAY, AND INTO TONIGHT,
AS A LOW-LEVEL JET GRADUALLY INTENSIFIES.
SATELLITE IMAGERY SHOWS AN EXTENSIVE AREA OF STRATUS FROM ABOUT THE
SOUTHWEST TIP OF INDIANA THROUGH SOUTHERN ILLINOIS AND THEN INTO
MISSOURI. GUIDANCE HAS NOT BEEN HANDLING THIS STRATUS DECK WELL, BUT
A FEW CAMS ARE HINTING AT IT REACHING PORTIONS OF OUR AREA BY
MORNING. IT MAY BE PRESENT TO SOME EXTENT THROUGHOUT THE DAY,
ESPECIALLY SOUTH AND EAST. ADDITIONALLY, THERE ARE SOME INDICATIONS
THAT SOME DRIZZLE MAY DEVELOP THIS EVENING AS THE LOW-LEVEL JET
INTENSIFIES FURTHER.
TEMPERATURES TODAY ARE DEPENDENT ON THE SNOW PACK AND POTENTIAL
CLOUD COVER. DESPITE ONGOING WARM AIR ADVECTION, SNOW COVER WILL
PROVIDE AN EFFECTIVE COUNTER BALANCE. SNOW, WITH ITS HIGH ALBEDO,
ACTS TO REFLECT INCOMING SOLAR RADIATION ALLOWING FOR COOLER
TEMPERATURES. ADDITIONALLY, ANY CLOUD COVER WILL FURTHER LIMIT THE
EFFECTIVENESS OF SOLAR RADIATION. THE COLD AIR OVER THE SNOW WILL
LIKELY STRENGTHEN THE BOUNDARY LAYER INVERSION WHICH LIMITS MIXING,
FURTHER REDUCING HOW MUCH WARMING CAN OCCUR. THAT BEING SAID, WE'VE
LOWERED TEMPERATURES FROM GUIDANCE ACROSS THE PORTIONS OF THE CWA
WITH THE DEEPER SNOWPACK.
ONGOING WARM AIR ADVECTION AND INEFFECTIVE RADIATIONAL COOLING MAY
KEEP LOWS NEAR 30 TONIGHT...QUITE WARM COMPARED TO WHAT WE'VE BEEN
SEEING. BY LATE TONIGHT, THE LOW OVER CANADA SHOULD BE DEPART
EASTWARD WITH SURFACE HIGH PRESSURE SETTLING OVER THE MIDWEST US.
WINDS MAY DIMINISH ENOUGH BY MORNING TO ALLOW FOR A BRIEF PERIOD OF
EFFICIENT COOLING ACROSS NORTHWESTERN PORTIONS OF THE AREA. MOISTURE
ADVECTED NORTHWARD BY THE LLJ MAY LEAD TO PATCHY FOG POTENTIAL
WEDNESDAY MORNING. SHOULD WINDS REMAIN ELEVATED, THEN A LOW STRATUS
DECK IS MORE LIKELY THAN FOG. WE'LL LIMIT THE MENTION OF FOG TO
PATCHY FOR NOW.
LONG TERM (WEDNESDAY THROUGH MONDAY)
ISSUED AT 246 AM EST TUE DEC 16 2025
OVERALL, ACTIVE, CHANGEABLE WEATHER IS EXPECTED FROM WEDNESDAY
THROUGH MONDAY. THIS IS DUE TO MODERATE WAVES PASSING WITHIN THE
FLOW ALOFT, HOWEVER, NO INTRUSIONS OF TRULY ARCTIC AIR ARE EXPECTED.
ON WEDNESDAY, RIDGING WILL BE IN PLACE OVER INDIANA WHILE A NEARLY
ZONAL FLOW WILL REMAIN ALOFT. THIS WILL LEAD TO ANOTHER DAY OF DRY
AND WARMING WEATHER. FORECAST SOUNDINGS HERE REVEAL THE EXPECTED
PRESENCE OF HIGH CLOUD ALOFT DUE TO UPPER LEVEL SATURATION, THUS
PARTLY SUNNY. SOUTHERLY LOWER LEVEL FLOW SHOULD ALLOW FOR HIGHS TO
REACH INTO THE 40S.
ON WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...A QUICK MOVING WAVE WILL
PUSH OUT OF THE NORTHERN PLAINS AND PUSH TOWARD INDIANA ON THURSDAY
BEFORE EXITING THE STATE LATE THURSDAY NIGHT. SEVERAL LOWER LEVEL
FEATURES ALSO ARE IN PLAY. A STRONG WARM FRONT WILL SURGE NORTHWARD
ON WEDNESDAY NIGHT, SETTING UP A STRONG WARM AIR ADVECTION PATTERN
AND FORECAST SOUNDING BEGIN TO TREND TOWARD SATURATION. BEST
ISENTROPIC LIFT DOES NOT APPEAR TO ARRIVE UNTIL THURSDAY AS FORECAST
SOUNDINGS TREND TOWARD SATURATION AT THAT TIME, WITH PWATS NEAR 1
INCH. PTYPE WILL BE RAIN WITHIN THE WARM SECTOR AS LEVELS BELOW
725MB OR LOWER (MY USAGE HERE, LOWER MEANING CLOSER TO THE SURFACE)
WILL BE ABOVE FREEZING. BEST CHANCES WILL BE DURING THE AFTERNOON
AND EVENING AS THE COLD FRONT PASSES. THUS EXPECT HIGHEST POPS AT
THAT TIME.
MUCH COLDER AND DRY AIR WILL ARRIVE IN THE WAKE OF THE FRONT ON
THURSDAY NIGHT. HERE, FORECAST SOUNDINGS TREND TOWARD A DRY COLUMN
AS SUBSIDENCE COMES INTO PLAY. THAT WILL BEGIN OUR NEXT STRETCH OF
DRY WEATHER.
FRIDAY THROUGH MONDAY...MAINLY DRY WEATHER WILL BE EXPECTED DURING
THIS PERIOD, HOWEVER A WEAKER UPPER SHORT WAVE IS SUGGESTED TO PASS
ON SATURDAY NIGHT WITHIN THE QUICK FLOW ALOFT. BEST FORCING DYNAMICS
FOR THIS FEATURE STAY ACROSS THE GREAT LAKES, WELL NORTH OF INDIANA
AND FORECAST SOUNDINGS DO NOT REVEAL DEEP SATURATION AT THAT TIME. A
WEAK COLD FRONT WILL PASS WITH THIS FEATURE ON SATURDAY NIGHT BUT
AGAIN THE BEST FORCING REMAINS NORTH. THE NBM MAY INCLUDE SOME LOW
CHANCE POPS AT THAT TIME, BUT CONFIDENCE IS LOW FOR THAT OUTCOME.
HIGH PRESSURE IS EXPECTED TO BE PRESENT ON EACH SIDE OF THIS COLD
FRONT, ON FRIDAY AND SATURDAY AND AGAIN ON SUNDAY INTO MONDAY,
BRINING DRY WEATHER WITH SLIGHTLY ABOVE NORMAL TEMPERATURES.
LOOKING AHEAD TOWARD DEC 25, MODELS CONTINUE TO TREND TOWARD ANOTHER
QUICK MOVING COLD FRONT PASSAGE ON DEC 24, WITH PTYPE SUGGESTED AS
RAIN. WARMER, ABOVE NORMAL TEMPERATURE APPEAR TO BE SUGGESTED WITH
NO SIGNAL PRESENT FOR A NEW SNOW EVENT.
AVIATION (12Z TAF ISSUANCE)
ISSUED AT 632 AM EST TUE DEC 16 2025
IMPACTS:
- MVFR STRATUS AT HUF, BMG, POSSIBLY IND
- LOW-LEVEL WIND SHEAR AFTER 00Z
DISCUSSION:
A TROUGH PASSING OVER THE NORTHERN GREAT LAKES WILL PROMOTE
INCREASING SOUTHWESTERLY FLOW THROUGH THE TAF PERIOD. BY TONIGHT, A
STRONG LOW-LEVEL JET IS EXPECTED WHICH WILL RESULT IN SOME LOW-LEVEL
WIND SHEAR AT ALL TERMINALS. AT THE SURFACE, SW WINDS AROUND OR A
LITTLE ABOVE 10KT ARE EXPECTED AS WELL. A FEW GUSTS AROUND 20KT
CANNOT BE RULED OUT THIS AFTERNOON.
MOISTURE ADVECTION NORTHERN BY THE LOW-LEVEL JET IS ALREADY ONGOING
FROM ABOUT VINCENNES SOUTHWARD, SEEN ON SATELLITE AS AN EXTENSIVE
AREA OF LOW STRATUS. THERE ARE SOME INDICATIONS WITHIN GUIDANCE THAT
THESE CLOUDS MAKE IT DEEPER INTO INDIANA THIS MORNING. UPSTREAM
OBSERVATIONS SHOW MVFR CEILINGS IN THE 2000-2500FT RANGE. GUIDANCE
SHOWS SIMILAR CEILINGS ACROSS INDIANA, PERHAPS DROPPING AS LOW AS
2000FT DUE TO A COOLER BOUNDARY LAYER WITH NORTHWARD EXTENT. STRATUS
SHOULD BEGIN TO EXIT EASTWARD BY MID AFTERNOON.
TONIGHT MAY SEE SOME ADDITIONAL STRATUS, PERHAPS DRIZZLE AS WELL,
LIFT NORTHWARD AS THE AFOREMENTIONED TROUGH MAKES ITS CLOSEST
APPROACH. LOW CONFIDENCE ON MVFR CEILINGS RETURNING, BUT HIGHER
CONFIDENCE IN THICK MID TO UPPER-LEVEL CLOUD COVER. CLOUDS DIMINISH
ON WEDNESDAY AS THE SYSTEM LIFTS NORTHEASTWARD.
IND WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...KF
SHORT TERM...ECKHOFF
LONG TERM...PUMA
AVIATION...ECKHOFF
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