521
FXUS63 KARX 231201
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
601 AM CST TUE DEC 23 2025
KEY MESSAGES
- SEASONABLY WARM THROUGH THE WEEK WITH HIGHS RUNNING NEARLY 10
DEGREES ABOVE NORMAL, BUT COLDER AIR LURKS ON THE HORIZON FOR
SUNDAY AND MONDAY WITH TEMPERATURES FALLING BY 20-25 DEGREES.
- ASIDE FROM THE RISK FOR DRIZZLE WEDNESDAY AFTERNOON, THE
CHRISTMAS EVE/CHRISTMAS FORECAST IS SHAPING UP TO BE DRY AND
WARM.
- NEXT CHANCE OF WIDESPREAD PRECIPITATION COMES THURSDAY NIGHT/
FRIDAY MORNING. THERE IS AN INCREASING RISK FOR FREEZING RAIN
ALONG THE NORTH OF I-94, BUT CONFIDENCE IN LOCATION OF THE
PRECIPITATION AND TEMPERATURES REMAINS IN FLUX.
DISCUSSION
ISSUED AT 200 AM CST TUE DEC 23 2025
TODAY/TONIGHT: BRIEF COOL DOWN TONIGHT BUT STILL WARM
A DECAYING SURFACE CYCLONE IS LIFTING THROUGH THE AREA OVERNIGHT
WITH THE PARENT UPPER LEVEL SHORTWAVE BEGINNING TO OUTRUN THE
LOW. WHILE WINDS SWITCH TO THE NORTHWEST IN ITS WAKE BY SUNRISE,
THE MAIN PUSH OF COLDER AIR LINGERS UP IN NORTH DAKOTA AND DOES
NOT ARRIVE UNTIL THIS EVENING. THEREFORE, EXPECT HIGHS FOR
TODAY TO BE SIMILAR TO YESTERDAY UNDER A MIX OF SUN AND CLOUDS.
EVEN THE COLDER AIR DOES NOT STICK AROUND LONG. SURFACE RIDGING
TRANSLATES THROUGH THE REGION OVERNIGHT AND RETURN SOUTHEASTERLY
FLOW ARRIVES BY SUNRISE ON WEDNESDAY, SETTING THE STAGE FOR A
WARM HOLIDAY PERIOD.
CHRISTMAS EVE/DAY: MOSTLY DRY AND WARM
A SHALLOW 700-500-MB WAVE CRESTS THE MEAN LONGWAVE TROUGH THAT
IS BRINGING US THIS STRETCH OF WARMER AND DRIER WEATHER. IN
DOING SO, A RIBBON OF SURFACE-850-MB MOISTURE IS PROGGED TO LIFT
THROUGH EASTERN IOWA AND INTO SOUTHERN WISCONSIN BY WEDNESDAY
AFTERNOON AND EVENING. IN ADDITION TO BRINGING MORE CLOUDS,
THERE LOOKS TO BE ENOUGH ISENTROPIC UPGLIDE WITHIN THE NEARLY
1-KM DEEP LOWER TROPOSPHERIC MOISTURE PLUME TO GENERATE DRIZZLE,
MAINLY ALONG AND SOUTH OF I-90 IN THE LOCAL FORECAST AREA. THE
LOW CLOUDS AND TIME OF DAY SHOULD LIMIT THE RISK FOR ANY
FREEZING DRIZZLE, BUT IT REMAINS A FRINGE SOLUTION (<10%) THAT A
FEW LOCALES COULD SEE SOME SLICK SPOTS. QPF AMOUNTS ARE QUITE
LIGHT (A FEW HUNDRETHS AT THE MOST), BUT GIVEN THE LOW QPF
AMOUNTS, DID HAVE TO MANUALLY PUSH THE NBM POPS HIGHER TO HAVE
DRIZZLE MENTIONED IN THE FORECAST.
THE DRIZZLE PUSHES OUT WEDNESDAY NIGHT AS THE FLOW TURNS
NORTHERLY IN THE WAKE OF THE PASSING MID TO UPPER TROPOSPHERIC
WAVE. ONCE AGAIN, GIVEN THE LOW AMPLITUDE NATURE OF THE TROUGH,
THE FLOW REVERTS BACK TO THE EAST-SOUTHEAST BY THURSDAY
AFTERNOON. BETWEEN THE DRIZZLE AND CLOUDS, THE WARMEST SURFACE
AIR MASS REMAINS REMAINS WELL SOUTH OF THE REGION, BUT WE REMAIN
UNDER THE INFLUENCE OF THE WARMER 925-700-MB AIR THAT KEEPS OUR
TEMPERATURES 5-10 DEGREES ABOVE NORMAL FOR THE CHRISTMAS
HOLIDAY (AVERAGE HIGHS IN THE MID-20S TO LOW 30S, FORECAST HIGHS
IN THE MID TO UPPER 30S).
THURSDAY NIGHT - FRIDAY MORNING: WINTRY MIX POTENTIAL
THE NEXT NOTABLE CHANCE OF PRECIPITATION THURSDAY NIGHT INTO
FRIDAY MORNING POSES A CHALLENGE TO THE FORECAST WITH REGARDS TO
THE EXTENT OF ANY FREEZING RAIN/DRIZZLE. TRENDS OVER THE LAST
FEW DAYS ARE FAVORING THE NORTHERN AND SOUTHERN STREAM MID-
TROPOSPHERIC WAVES TO REMAIN EVER SO SLIGHTLY OUT OF PHASE AS
THEY TRANSECT THE REGION, RESULTING IN COLDER AIR REMAINING
NEAR THE SURFACE UNDER AN ESE FLOW REGIME. AS THE SURFACE TO
850-MB LOW LIFTS NORTHEASTWARD FROM KANSAS, HIGHER THETA-E AIR
AND ISENTROPIC ASCENT OVERSPREADS THIS COOLER BOUNDARY LAYER
AIRMASS AND SETS THE STAGE FOR FREEZING RAIN. WITH THE FORECAST
TRENDING COOLER, THE RISK FOR MENTIONABLE FREEZING RAIN IS
CREEPING SOUTHWARD AND NOW INCLUDES THE I-94 CORRIDOR WITH THE
LATEST NBM RUNS.
THIS RISK COULD SPREAD EVEN FURTHER SOUTH IF WE FAIL TO SEE
TEMPERATURES RECOVER AS FAST DURING THE DAY ON THURSDAY, WITH
5-10% OF THE LREF MEMBERS BRINGING THE FREEZING RAIN RISK AS FAR
SOUTHWEST AS ROCHESTER AND LA CROSSE. THIS IS A SCENARIO THAT
BEARS CLOSE WATCHING AS WE GET CLOSER TO THE EVENT. IN ADDITION
TO THE EXACT SURFACE TEMPERATURES, GIVEN THE EVOLVING STRUCTURE
OF THE CYCLONE AS IT LIFTS THROUGH THE REGION, THE PLACEMENT OF
THE PRECIPITATION SHIELD IS A LOWER CONFIDENCE ASPECT OF THIS
FORECAST AND RESULTING IN LOWER POPS FROM THE NBM. OVERALL
LIQUID PRECIPITATION AMOUNTS DO LOOK TO BE LIGHT REGARDLESS,
BUT AS RECENT EVENTS HAVE SHOWN, IT DOES NOT TAKE MUCH ICING TO
CAUSE SIGNIFICANT TRAVEL IMPACTS.
WARM END TO THE WEEK, COLD TO START NEXT WEEK
WITH THE OVERALL PATTERN AMPLIFYING THROUGH THE END OF THE
WEEK, FRIDAY AND SATURDAY LOOK TO BE OUR WARMEST DAYS WITH MANY
LOCALES CRACKING THE 40 DEGREE MARK. IN FACT, ABOUT 10% OF THE
LONGER RANGE ENSEMBLE MEMBERS HAVE AREAS ALONG THE SAME LATITUDE
AS DUBUQUE CLOSING IN ON 50 DEGREES. THE LONGWAVE PATTERN
FINALLY SHIFTS LATE SATURDAY AND A STRONG COLD FRONT RACES
THROUGH THE REGION, SENDING TEMPERATURES TUMBLING INTO THE
SINGLE DIGITS FOR LOWS BY MONDAY MORNING. WHETHER WE SEE ANY
PRECIPITATION WITH THIS COLD FRONTAL PASSAGE IS LOWER CONFIDENCE
ASPECT OF THIS FORECAST DEPENDENT ON HOW QUICKLY THE ATTENDANT
SURFACE CYCLONE CAN MATURE.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 529 AM CST TUE DEC 23 2025
IFR CEILINGS SAGGING SOUTHEAST THROUGH CENTRAL MINNESOTA RAISE
AVIATION IMPACT CONCERNS LOCALLY ALTHOUGH OVERALL CONFIDENCE IS
LOW AS DRIER AIR LOCALLY EXPECTED TO LIFT IMPACTS.
DRIZZLE CHANCES INCREASE WEDNESDAY AFTERNOON/EVENING, PRIMARILY
AFFECTING SMALLER AIRPORTS IN SOUTHERN WISCONSIN. SUBSEQUENT
IMPACTS FROM PRECIPITATION, POTENTIALLY FREEZING RAIN, THURSDAY
NIGHT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...JAR
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