378
FXUS63 KARX 141949
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
149 PM CST SUN DEC 14 2025
KEY MESSAGES
- WHILE APPARENT TEMPERATURES STAYING BELOW ZERO TONIGHT,
GRADUAL WARMING TO START THE WEEK WITH HIGH CONFIDENCE FOR
ABOVE FREEZING SURFACE TEMPERATURES COME TUESDAY.
- INITIAL MOSTLY RAIN WEDNESDAY NIGHT POTENTIALLY SWITCHES OVER
TO WIDESPREAD SNOW THROUGH THURSDAY. FREEZING RAIN APPEARS
UNLIKELY.
DISCUSSION
ISSUED AT 113 PM CST SUN DEC 14 2025
GRADUAL WARMING TO START THE WEEK:
WHILE TODAY'S SUN ANGLE IS JUST 0.1 DEGREE ABOVE THE ANNUAL
MINIMUM AND ALBEDO IS HIGH, APPARENT TEMPERATURES HAVE RISEN
CONCURRENT WITH DAYTIME HEATING INTO THE SINGLE DIGITS BELOW
ZERO FOR MUCH OF THE FORECAST AREA. ULTIMATELY, THE LOCAL
WARMING TREND CAN BE ATTRIBUTED TO THE MAIN PLUME OF
ANOMALOUSLY COLD LOW LEVEL ARCTIC AIR EXITING SOUTH THROUGH THE
MID MISSISSIPPI RIVER VALLEY ON EARLY AFTERNOON ACARS.
CONCURRENT WAA ALSO INITIALLY ADVECTING EAST THROUGH THE
CENTRAL PLAINS.
A SYNOPTIC UPPER LEVEL RIDGE OVER THE ROCKY MOUNTAIN WEST ON GOES
WATER VAPOR IMAGERY EARLY THIS AFTERNOON IS UNDER THE INFLUENCE
OF A PERIPHERAL UPPER LEVEL JET STREAK PERTURBATION ACCORDING
TO GOES DERIVED 250-350MB WINDS. THE RESULTANT SOUTHEAST SHUNT
TO THE RIDGE AXIS OVERNIGHT THROUGH MONDAY MORNING DRIVES AN
ACCOMPANYING LOW LEVEL TROUGH ALONG THE INTERNATIONAL BORDER
INTO THE NORTHERN GREAT LAKES OVERNIGHT INTO EARLY MONDAY
MORNING. THE RESULTANT TIGHTENED LOW LEVEL ISOHEIGHT GRADIENT
WILL STRENGTHEN SURFACE WINDS LOCALLY. THEREFORE, WHILE WELCOMING
OVERNIGHT SURFACE WARMING INTO THE TEENS, APPARENT TEMPERATURES
EXPECTED TO REMAIN BELOW ZERO UNTIL DIURNAL HEATING MONDAY.
CURRENT CLUSTER AND INDIVIDUAL ENSEMBLE CONFIDENCE KEEPS THE
SYNOPTIC PATTERN QUASI-ZONAL THROUGH MIDWEEK, STABILIZING LOCAL
SURFACE TEMPERATURES MOSTLY FROM THE 20S TO 30S FOR DAYTIME HIGHS
AND TEENS TO 20S FOR OVERNIGHT LOWS THROUGH WEDNESDAY. A COLD FRONT
ON THURSDAY RETURNS A BLAST OF ARCTIC AIR WITH ENSEMBLE CONFIDENCE
FOR NEAR FREEZING TEMPERATURES BY DAYBREAK COOLING TO BELOW ZERO
THROUGH THURSDAY NIGHT. SOLUTION TO THIS MIDWEEK WAVE LEAVES QUESTIONS
FOR EXACT TEMPERATURES LOCALLY INTO NEXT WEEKEND AS ENSEMBLE
CLUSTER CONFIDENCE IN MID LEVEL HEIGHTS DEPICTS A HEIGHT GRADIENT
ALONG AND NORTH OF THE FORECAST AREA WITH POTENTIAL ROLLING OPEN
WAVES ALONG THE INTERNATIONAL BORDER.
PRECIPITATION CHANCES MIDWEEK:
WIDESPREAD MIXED PRECIPTIATION CHANCES REACH THE UPPER MISSISSIPPI
RIVER VALLEY WEDNESDAY NIGHT INTO THURSDAY MORNING FROM A SYNOPTIC
TROUGH PHASING THROUGH THE CENTRAL CONUS. ENSEMBLE IQR SPREAD FOR
LOCATION OF THE MAIN LOW CENTER REMAINS NORTH OF THE FORECAST
AREA, MERIDIONALLY SPANNING THE HEIGHT OF NORTH DAKOTA. HOWEVER,
INTERACTION WITH SUPPLEMENTARY CYCLOGENESIS FARTHER SOUTH AIDED
BY A STRONGER MID LEVEL SYNOPTIC ENSEMBLE SOLUTION IS DRIVING
MODERATE PROBABILITIES (60-80%) FOR 0.1" OF QPF LOCALLY IN 24
HOURS. TIMING AND LOCATION OF PHASING WILL ALSO DICTATE LOCAL
SCENARIOS, AS A LATER PHASING HAS ADVECTED THE HIGHEST PROBABILITIES
FOR PRECIPITATION SLIGHTLY FARTHER EAST THROUGH CENTRAL IOWA.
EXPECT A MIX OF RAIN AND SNOW AS INITIAL ABOVE FREEZING
TEMPERATURES QUICKLY COOL THROUGH THE LEVELS, LEAVING LIMITED
WINDOW FOR FROZEN PRECIPITATION. THE HIGHEST PROBABILITIES FOR
1" (10:1 SLR) OF SNOWFALL HAVE SLIGHTLY SHIFTED NORTH OF THE
FORECAST AREA IN MOST RECENT LREF RUNS (14.12Z) TIED TO THE MAIN
LOCATION OF THE QUASI-ZONAL SURFACE LOW. HOWEVER MORE WIDESPREAD
LOWER PROBABILITIES (<30%) CAN BE ATTRIBUTED TO SLIGHTLY LONGER
DURATION IN PRECIPITATION THROUGH THURSDAY MORNING FROM THE
SOUTHERN STREAM OF CYCLOGENESIS AND KICK OF COLD ARCTIC AIR.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1140 AM CST SUN DEC 14 2025
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH INCREASING
MIDDLE AND UPPER-LEVEL CLOUDS THIS EVENING AND OVERNIGHT. WINDS
WILL INCREASE INTO THE EVENING AND OVERNIGHT TO AROUND 12-18
KTS WITH GUSTS OF AROUND 25-30 KTS WEST OF THE MISSISSIPPI
RIVER. WITH AN INCREASING LOW-LEVEL WIND FIELD OF 45 TO 55 KTS
IN RAP/HRRR/NAM SOUNDINGS AT AROUND 2KFT, HAVE OPTED TO INCLUDE
SOME LLWS MENTION AFTER 05Z MONDAY AT KLSE DUE TO LOWER
MAGNITUDE GUSTS TONIGHT. WITH KRST LIKELY GUSTING HIGHER, HAVE
NOT INCLUDED ANY LLWS MENTION. WINDS WILL DIMINISH SOME DURING
THE MORNING HOURS ON MONDAY TO AROUND 8-12 KTS.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...NAYLOR
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