860
FXUS63 KARX 191143
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
543 AM CST THU FEB 19 2026
KEY MESSAGES
- A COMPACT, BUT POTENT, BAND OF SNOW AFFECTS MAINLY NORTHEAST
IOWA INTO SOUTHWEST WISCONSIN TONIGHT INTO FRIDAY MORNING.
THERE IS A 20- 40% CHANCE THAT THE HEAVIEST SNOW RATES EXCEED
1"/HR PER HOUR AND TOTAL SNOW AMOUNTS COULD EXCEED 6" IN A FEW
LOCALES (20-30% CHANCE).
- THE EXACT PLACEMENT AND SNOW AMOUNTS REMAIN A CHALLENGE OF THE
FORECAST. THE NORTHERN SIDE OF THE SNOW BAND IS ESPECIALLY
SENSITIVE AS THERE WILL BE A SHARP CUTOFF IN SNOW AMOUNTS AND
IMPACTS OVER JUST A FEW MILES.
- "COLDER", AKA NEAR OR SLIGHTLY BELOW NORMAL, TEMPERATURES MOVE
IN FOR THE END OF THE WEEK AND EARLY NEXT WEEK. THESE
TEMPERATURES LOOK TO REBOUND SOMEWHAT FOR NEXT TUE/WED.
- LIGHT SNOW MOVES THROUGH FOR THE WEEKEND, OTHERWISE NO MAJOR
WEATHER SYSTEMS OF NOTE ARE ON THE DOCKET THROUGH AT LEAST THE
MIDDLE PART OF NEXT WEEK.
DISCUSSION
ISSUED AT 241 AM CST THU FEB 19 2026
TONIGHT - FRIDAY MORNING: SNOW BAND DETAILS
THE UPPER LEVEL SHORTWAVE RESPONSIBLE FOR OUR BAND OF MODERATE
TO HEAVY SNOW LATER TONIGHT INTO FRIDAY MORNING MADE LANDFALL
ACROSS THE NORTHERN CALIFORNIA COAST ABOUT 6-12 HOURS AGO AND IS
NOW BEING SAMPLED BY THE UPPER AIR NETWORK. THIS HAS RESULTED
IN THE PREVIOUSLY DIVERSE SUITE OF SOLUTIONS CONVERGING QUICKLY
ON THE SOUTHEASTWARD SIDE OF THE ENSEMBLE ENVELOPE, TAKING THE
SNOW BAND ACROSS NORTHEAST IOWA AND INTO SOUTHWESTERN WISCONSIN.
THIS PV LOBE, VERY EVIDENT IN WATER VAPOR IMAGERY, IS
PROGRESSING RAPIDLY ALONG THE SOUTHERN FLANK OF THE MEAN
LONGWAVE TROUGH AND REACHES THE HIGH PLAINS BY MIDDAY AND THE
MID-MISSOURI RIVER VALLEY THIS EVENING. A LEE CYCLONE ALREADY
TAKING SHAPE ALONG THE COLORADO FRONT RANGE PEELS OFF ACROSS
KANSAS AND THE LOWER MISSOURI RIVER VALLEY THIS MORNING,
REACHING AROUND KEOKUK, IA BY THIS EVENING AND INTO LOWER LAKE
MICHIGAN BY SUNRISE FRIDAY.
A STOUT DEFORMATION ZONE/FRONTOGENESIS BAND DEVELOPS ALONG THE
NORTHWEST FLANK OF THE LOW WITHIN A REGION OF ENHANCED UPPER
TROPOSPHERIC DIVERGENCE IN THE LEFT FRONT QUADRANT OF A 170-KT
JET STREAK. AMPLE GULF MOISTURE IS PROGGED TO WRAP AROUND THE
LOW WITH UPPER LEVEL SPECIFIC HUMIDITY VALUES AROUND THE 90TH
PERCENTILE OF CLIMATOLOGY. THE MEAN QPF FORECAST WITHIN THIS
BAND IS OVER HALF AN INCH WITH 20-30% OF THE ENSEMBLE MEMBERS
PAINTING A NARROW CORRIDOR OF PRECIPITATION VALUES AROUND OR
JUST OVER 1". THE QUESTION OF COURSE IS: WHERE WILL THE SNOW
FALL AND HOW MUCH?
STARTING WITH THE POSITION OF THE BAND--THE 00Z ENSEMBLES HAVE
COME INTO MUCH BETTER AGREEMENT WITH THE PREVIOUSLY NOTED
SOUTHEASTWARD SHIFT IN THE QPF/SNOW AXIS, AND HAVE TRENDED THE
OFFICIAL FORECAST IN LINE WITH THIS SHIFT. THIS PLACES THE
CORRIDOR OF HEAVIEST SNOW ALONG A ROUGH LINE FROM INDEPENDENCE,
IA TO BOSCOBEL, WI AND THEN TOWARDS WISCONSIN DELLS. THIS
CORRIDOR IS STILL LIKELY TO WOBBLE OVER THE NEXT 12-18 HOURS
GIVEN THE FAST MOTION AND DYNAMIC NATURE OF THE WAVE. THERE WILL
BE A SHARP CUTOFF IN SNOW AMOUNTS ON EITHER SIDE OF THIS SNOW
BAND, PARTICULARLY THE NORTHERN SIDE WHERE INDIVIDUAL MODELS
SHOW SNOW AMOUNTS GOING FROM 6" TO DRY IN THE SPAN OF 10 TO 15
MILES.
NOW, HOW MUCH SNOW COULD FALL WITHIN THIS DEFORMATION BAND IS A
BIT TRICKIER TO UNPACK. ON FACE VALUE, THE QPF AMOUNTS FROM THE
VARIOUS DETERMINISTIC AND ENSEMBLE MEMBERS IS RATHER SCARY. THE
OMEGA PROFILES THROUGH THE DGZ RESEMBLE A CLASSIC CROSS-HAIRS
SOUNDING WITH AN IMPRESSIVE MAXIMUM NEAR OR SLIGHTLY UNDER THE
DGZ. HOWEVER, THE SNOW SYSTEM IS FAST HITTING--IN AND OUT IN
ABOUT 6-9 HOURS. TO ACHIEVE THE HIGHER END SNOW AMOUNTS PROGGED
BY SOME OF THE GUIDANCE, WE WOULD NEED TO SEE 1-2" SNOWFALL
RATES FOR NEARLY THE ENTIRETY OF THE EVENT. HISTORICALLY, THIS
RARELY HAPPENS IN THESE ENVIRONMENTS CHARACTERIZED BY HIGHER
LIQUID CONTENT AND LOWER SNOW RATIOS. THE DGZ IS ALSO NOT OVERLY
DEEP (50-100 MB), ANOTHER LIMITING FACTOR FOR EXCESSIVE SNOW
AMOUNTS. IT WILL STILL SNOW QUITE HEAVILY FOR A PERIOD AND THERE
IS A 20-30 PERCENT CHANCE THAT A GIVEN LOCATION IN NORTHEAST
IOWA AND SOUTHWEST WISCONSIN SEES 6 INCHES OF SNOW, BUT SOME OF
THE OUTLIER SOLUTIONS OF 10-15 INCHES JUST SEEM VERY FAR FETCHED
GIVEN THE SETUP.
THERE IS ALSO THE POSSIBILITY OF SEEING FREEZING DRIZZLE NORTH
OF THIS SNOW BAND AS SHOWN IN SOME SOUNDINGS THAT LOSE ICE WITH
LIFT STILL PRESENT, BUT THE WINDOW OF OPPORTUNITY FOR THIS TO
OCCUR IS RATHER NARROW AND CONFIDENCE IS ONLY ABOUT 10-20% IN
THERE BEING ANY IMPACTS. WILL NEED TO MONITOR TRENDS THROUGHOUT
THE DAY AND SEE IF THIS RISK BECOMES MORE DEFINED.
WE'RE NOW AT 24 HOURS FROM THE EVENT, SO WHILE THE FORECAST
REMAINS FLUID AND SUBJECT TO CHANGE, HAVE GONE AHEAD AND ISSUED
A WINTER WEATHER ADVISORY FOR WHERE CONFIDENCE IS HIGHEST FOR
IMPACTFUL SNOW. THERE WILL LIKELY BE ADJUSTMENTS MADE TO THE
FOOTPRINT OF THE ADVISORY THROUGHOUT THE DAY/EVENING AND THE
POSSIBILITY OF A NARROW WARNING NEEDED IF CONFIDENCE INCREASES
FOR A 6+ INCH BAND.
THE WEEKEND: COLDER, LIGHT SNOW
POLAR AIR LURKING OVER THE WESTERN DAKOTAS THIS MORNING FINALLY
STARTS TO FILTER SOUTHEAST IN THE WAKE OF TONIGHT'S SYSTEM, BUT
GIVEN THE COMPLEX UPPER LEVEL TROUGH PATTERN AND AN UPSTREAM
TROUGH DEEPENING AS IT MOVES ACROSS THE ROCKIES, THERE WILL NOT
BE A COHESIVE PUSH TO BRING THIS COLDER AIR INTO THE REGION
UNTIL LATER IN THE WEEKEND AS THE TROUGH MOVES THROUGH. THE END
RESULT WILL BE A STEADILY COOLING FOR FRIDAY THROUGH SUNDAY,
WITH HIGHS IN THE LOW TO MID 20S FOR SUNDAY AND LOWS MONDAY
MORNING IN THE SINGLE DIGITS. THE PASSAGE OF THIS AFOREMENTIONED
UPPER LEVEL TROUGH IS ALSO THE FOCUS FOR A ROUND OF LIGHT SNOW
SATURDAY NIGHT AND SUNDAY. IMPACTS AT THIS TIME LOOK TO BE LIGHT
(1-2" OF SNOW AT THE MOST) AND MAINLY EAST OF THE MISSISSIPPI
RIVER.
EARLY NEXT WEEK: WARMING AND MOSTLY DRY
SYNOPTIC LONGWAVE RIDGING ACROSS THE WESTERN CONUS FLATTENS AND
SHIFTS EASTWARD FOR THE START OF NEXT WEEK, WHICH WILL HAVE THE
EFFECT OF SHUNTING OUR COOLER AIR BACK TO THE NORTH. HOWEVER,
HOW THIS RIDGE BREAKS DOWN REMAINS LESS CERTAIN AND WILL PLAY A
ROLE IN OUR TEMPERATURE AND PRECIPITATION FORECAST FOR MIDWEEK
AND BEYOND. THERE IS GOOD AGREEMENT THAT A PACIFIC AIRMASS
SPREADS ACROSS THE HIGH PLAINS AND INTO THE REGION FOR TUESDAY,
RESULTING IN HIGH TEMPERATURES RETURNING TO THE MID 30S TO
AROUND 40 (POSSIBLY INFLUENCED BY WHERE WE HAVE SNOW ON THE
GROUND). THE INTERQUARTILE TEMPERATURE SPREAD INCREASES TO 10-15
DEGREES BEYOND TUESDAY (20-25 DEGREES FOR THE 10TH TO 90TH
PERCENTILES), A FUNCTION OF HOW QUICKLY THE RIDGE FLATTENS AND
HOW FAR SOUTH IT SINKS LATER IN THE WEEK.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 540 AM CST THU FEB 19 2026
MVFR TO HIGH IFR STRATUS LINGERS FOR MUCH OF THE AREA NORTH OF
AN OVS TO OLZ LINE THIS MORNING. CURRENT TRENDS INDICATE LITTLE
IN THE WAY OF IMPROVEMENTS PRIOR TO OUR NEXT SYSTEM ARRIVING
THIS EVENING, WHICH WILL BRING CONTINUED WIDESPREAD MVFR TO IFR
CONDITIONS WITH VISIBILITY REDUCTIONS OF LESS THAN 1SM IN HEAVY
SNOW AFFECTING SITES ALONG A SOMEWHAT NARROW LINE FROM OLZ TO
OVS TO DLL OVERNIGHT. THIS SNOW STARTS TO CLEAR AT THE END OF
THE TAF PERIOD AND CONTINUES TO EXIT FRIDAY MORNING. WINDS WILL
BE LIGHT FROM THE WEST TO NORTH THIS MORNING, INCREASING FROM
THE NNE THIS EVENING AT 5 TO 15 KTS, WITH GUSTS UP TO 25-30 KTS
OVERNIGHT AS WINDS BACK TO THE NORTHWEST.
ARX WATCHES/WARNINGS/ADVISORIES
WI...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 AM CST
FRIDAY FOR WIZ042>044-053>055-061.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 AM CST
FRIDAY FOR IAZ011-029-030.
DISCUSSION...SKOW
AVIATION...SKOW
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