Area Forecast Discussion
Issued by NWS La Crosse, WI

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635
FXUS63 KARX 021741
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1141 AM CST TUE FEB 2 2016

.UPDATE...
ISSUED AT 1141 AM CST TUE FEB 2 2016

CURRENT RADAR/SURFACE OBSERVATIONS SHOWING HEAVY SNOW BAND MOVING
ALONG/NORTH OF THE I-90 CORRIDOR AT PRESENT. A LOT OF 3 TO 6 INCH
REPORTS COMING IN UNDER THE HEAVY SNOW BAND. MESO MODELS ARE
SHOWING THIS BAND WILL CONTINUE TO LIFT NORTH WITH HEAVIEST
DEFORMATION BANDED SNOW EXTENDING FROM APPROXIMATELY ROCHESTER MN
TO NEILSVILLE WI GOING INTO THIS AFTERNOON/TONIGHT. SOUTH OF
THIS...WILL LIKELY SEE TAPERING TREND IN THE ACCUMULATING SNOW
WITH EVEN SOME DRIZZLE/FREEZING DRIZZLE WORKING IN AS DRY SLOT OF
THE STORM ROTATES IN FROM THE SOUTHWEST. MAY NEED TO DO SOME
REVAMPING ON POPS SNOW TOTALS AND MAKE HEADLINE ADJUSTMENTS GOING
INTO THIS AFTERNOON. WILL CONTINUE TO CLOSELY MONITOR THE
EVOLUTION OF THE STORM SYSTEM.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST TUE FEB 2 2016

ALL EYES FOCUSED DIRECTLY ON THE IMPENDING WINTER STORM. LEADING
EDGE OF THE FRONTOGENETIC DRIVEN RADAR RETURNS ALREADY INTO
NORTHERN WI AND SOUTHERN WI. NOTHING REACHING THE GROUND INITIALLY
AS THERE IS A DRY LOWER LAYER THAT HAS TO BE OVERCOME FIRST. THE
MAIN DYNAMICALLY DRIVEN SNOW IS STILL WELL TO THE SOUTH IN
KS/MO/NE AND SOUTHERN IA. BUT THAT AREA IS QUICKLY MOVING
NORTHEAST AS THE MAIN UPPER SYSTEM CONTINUES TO CHURN NORTHEAST
ACROSS THE PLAINS. IMPRESSIVE JET ROUNDING THE BASE OF THE TROUGH
WITH THE INITIAL SHORT WAVE EMBEDDED IN THE CLOSED CIRCULATION.
BROAD UPPER DIFLUENCE SEEN IN BOTH SATELLITE IMAGERY AND MODEL
PLAN VIEW GRAPHICS. SYSTEM IS EXPECTED TO REACH ITS PEAK STRENGTH
AS IT MOVES INTO WESTERN IA AROUND SUNSET. UPWARD LIFT IS
INCREDIBLY STRONG WITH OMEGA ACTUALLY WRAPPING AROUND THE COLOR
SCALE ON OUR DISPLAYS. PERUSAL OF CONVECTIVE POTENTIAL INDICATES
BOTH UPRIGHT AND SLANTWISE COMPONENTS AVAILABLE DURING THE PEAK
FROM AFTERNOON INTO EARLY EVENING...SO CANNOT COMPLETELY RULE OUT
A RUMBLE OR TWO OF THUNDER AS WELL. WILL NOT ADD IT TO THE
FORECAST JUST YET...

THE RECENT TREND OF A SLIGHTLY MORE NORTHERLY TRACK IS STILL
THERE...WITH MORE WARMER AIR SNEAKING INTO THE SOUTHERN PORTIONS
OF OUR SERVICE AREA. THIS COULD PUT A LITTLE OF A DENT INTO THE
EVENTUAL SNOWFALL AMOUNTS...WITH SOME OF THE PRECIPITATION FALLING
AS RAIN. HAVE CONTINUED THE TREND THAT PREVIOUS SHIFTS STARTED BY
HAVING A WINTRY MIX IN THE SOUTHEAST THIRD OF OUR AREA. BUT
DESPITE THE PRESENCE OF THE WARMER AIR AND THE SLIGHT SHIFT...
STILL THINK IMPRESSIVE SNOW ACCUMULATIONS WILL BE SEEN. WHEN IT
DOES SNOW...CONVECTIVE POTENTIAL AND STRONG LIFT SUGGEST IT WILL
SNOW PRETTY HARD...WITH 1-2 INCH RATES FOR AT LEAST A FEW HOURS AT
EACH LOCATION.

ONCE THE INITIAL SURGE OF HEAVY SNOW BEGINS TO TAPER OFF...AND THE
MAIN DEFORMATION AREA SHIFTS A BIT TO THE NORTH...WE COULD HAVE A
PERIOD WHERE ONLY LIGHT SNOW PREVAILS. BUT THERE IS A SECONDARY
SHORT WAVE TROUGH THAT WILL ROTATE AROUND THE MAIN SYSTEM AND WILL
PASS ACROSS THE AREA DURING THE EVENING AND OVERNIGHT HOURS. THIS
WILL PROVIDE ANOTHER PERIOD OF SIGNIFICANT LIFT...AND COULD DROP
SEVERAL MORE INCHES OF SNOW. THIS DOUBLE-BARREL EFFECT SHOULD HELP
US REACH THE FORECAST SNOW TOTALS OF 6 TO AS MUCH AS 12 INCHES.

REFER TO THE LATEST STATEMENTS AND WARNINGS FOR DETAILS ON THE
SNOW AS IT AFFECTS THE AREA TODAY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 307 AM CST TUE FEB 2 2016

SNOW MAY LINGER INTO EARLY WEDNESDAY AS THE SYSTEM WEAKENS AND
MOVES AWAY. THE AREA WILL BE IN NORTHWEST FLOW BEHIND IT...AND THE
NEXT WEAK DISTURBANCE WILL ZIP THROUGH ON THURSDAY. MOISTURE WILL
BE LIMITED...BUT THERE SHOULD BE AT LEAST A SMALL CHANCE FOR SOME
LIGHT SNOW. ANOTHER ONE WILL FOLLOW FOR FRIDAY NIGHT INTO
SATURDAY.

OVERALL TRENDS SUGGEST TEMPERATURES WILL BE PRETTY MUCH NEAR
NORMAL. BUT THERE IS A SIGNIFICANT TROUGH THAT IS EXPECTED TO MOVE
INTO THE REGION FROM NORTHWEST CANADA ON SUNDAY. TEMPERATURES LOOK
TO WARM NICELY AHEAD OF IT WITH THE CORE OF THE SYSTEM PASSING TO
THE NORTH OF OUR AREA. BUT THIS TROUGH WILL CONTINUE TO AMPLIFY
ACROSS THE EASTERN PART OF THE COUNTRY BY EARLY NEXT WEEK...
ALLOWING A SURGE OF COLD ARCTIC AIR TO DROP IN BEHIND IT. LOWS
COULD BE BELOW ZERO AGAIN TUESDAY AND WEDNESDAY MORNING...WITH
HIGHS ONLY IN THE SINGLE DIGITS AND TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1141 AM CST TUE FEB 2 2016

WITH HEAVY SNOW AXIS WORKING THROUGH THE AREA CURRENTLY...BOTH
KRST/KLSE REPORTING BELOW 1/4SM THIS PAST HOUR.

EXPECT KRST TO REMAIN IN MODERATE/HEAVY SNOW BAND FOR THE REST OF
THIS AFTERNOON INTO TONIGHT...SLOWLY TAPERING OFF AFTER MIDNIGHT.
GUSTY NORTHEAST WINDS WILL SWITCH TO THE NORTH AND REMAIN QUITE
STRONG FROM 06Z ON FOR SOME BLOWING SNOW AS WELL. RIGHT
NOW...LOOKS LIKE 10-12 INCHES TOTAL SNOWFALL FOR THE AIRPORT
BEFORE TAPERING OFF BY 12Z. OTHERWISE...PLAN ON LIFR CONDITIONS
THROUGH TONIGHT...WITH SOME IMPROVEMENT AROUND 14Z INTO IFR.

FOR KLSE...LOOKS LIKE WORST OF THE HEAVY/ACCUMULATING SNOW WILL
WORK NORTH OF THE AREA BY 22Z...PERHAPS TRANSITIONING OVER TO A
MIX OF FZDZ/-SN THROUGH MIDNIGHT...THEN BECOMING MOSTLY SNOW AGAIN
AFTER 08Z. LOOK FOR THE SNOW TO TAPER OFF AFTER 12Z.
OTHERWISE...PLAN ON LIFR CONDITIONS...IMPROVING TO IFR AFTER
22Z...REMAINING THERE THROUGH 18Z WED.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR WIZ017-029-
     032>034-041>044-053>055-061.

MN...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR MNZ079-086>088-
     094>096.

IA...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR IAZ008>011-018-
     019-029-030.

&&

$$

UPDATE...DAS
SHORT TERM...MW
LONG TERM...MW
AVIATION...DAS



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