Winter Storm in Minnesota, February 15 to 16, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
240 PM CST WED FEB 15 2006

.SHORT TERM...TONIGHT THROUGH SATURDAY

FOCUS CONTINUES TO BE ON THE IMPENDING WINTER STORM TONIGHT THROUGH
THURSDAY NIGHT...THEN TEMPERATURES FRIDAY THROUGH SATURDAY.

SURFACE ANALYSIS THIS AFTERNOON HAS A LARGE AREA OF HIGH PRESSURE
EXTENDING FROM THE NORTHERN PLAINS INTO THE GREAT LAKES REGION.
MEANWHILE...A WAVE OF LOW PRESSURE WAS LOCATED OVER EASTERN KS WITH
A QUASI-STATIONARY FRONT EXTENDING NORTHEAST THROUGH SOUTHERN
IL/CENTRAL IN. DERIVED PW GOES PRODUCT SHOWING INCREASING GULF
MOISTURE STREAMING NORTHWARD AHEAD OF THE LOW VIA 30-35KT 925MB WIND
PER PROFILERS. MOISTURE TRANSPORT/ISENTROPIC LIFT CONTINUES TO
SATURATE THE COLUMN NORTH OF THE QUASI-STATIONARY BOUNDARY JUST TO
OUR SOUTH. IN FACT...RADARS SHOWING A RAPID EXPANSION OF ECHOES IN
THIS LIFT REGION ALONG THE WI/IL BORDER. GROUND OBSERVATIONS SHOWING
LOWEST CLOUD BASES/BOTTOM OF VIRGA AROUND 60KFT AT THIS TIME. WATER
VAPOR SATELLITE IMAGERY SHOWING ANOTHER...MORE POTENT SHORTWAVE
TROUGH MOVING INTO THE CENTRAL ROCKIES. THIS WAVE WAS PRODUCING
BROAD AREA OF 1-2SM -SN OVER WESTERN NEB/SD IN ADVANCE OF THE WAVE.
THIS WILL BE THE MAIN SNOW MAKER FOR TOMORROW FOR OUR REGION.

12Z 15FEB06 GFS/NAM MASS FIELDS VERIFYING FAIRLY WELL AT 18Z WHEN
COMPARED AGAINST SATELLITE DATA. MODELS REMAIN IN GOOD AGREEMENT
THROUGH THE PERIOD WITH HANDLING OF THE STORM TRACK...AND COLD AIR
INTRUSION BEHIND THE SYSTEM THURSDAY NIGHT THROUGH SATURDAY.

FOR TONIGHT...MID LEVEL WAVE/SURFACE LOW PRESSURE OVER EASTERN KS
RIPPLES NORTHEAST ALONG THE STALLED FRONTAL BOUNDARY/BAROCLINIC
RIBBON INTO NORTHERN IN BY THU 12Z. MAIN MOISTURE/LIFT ASSOCIATED
WITH THIS FEATURE STAYS SOUTH AND EAST OF THE AREA. HOWEVER...
STRONG ISENTROPIC LIFT AS EVIDENCED ON 280K SURFACE ON THE NAM
INCREASES FROM WEST TO EAST AS NEXT MORE POTENT WAVE PUSHES INTO THE
CENTRAL/SOUTHERN PLAINS. THIS WILL WORK ON ALREADY FAIRLY DEEP
SATURATED COLUMN LEFT BEHIND FROM THE LEAD WAVE. SO...WILL SEE
BASICALLY A CONTINUOUS -SN ALL THROUGH THE NIGHT ACROSS MUCH OF THE
AREA. 1-2 POSSIBLE ACROSS THE SOUTH AND CENTRAL PARTS OF FORECAST
AREA WITH AROUND A HALF INCH ACROSS FAR NORTH WHERE DRIER AIR WILL
RESIDE.

RAPID SURFACE CYCLOGENESIS TAKES PLACE OVER NORTHEAST MO BY MID
THURSDAY MORNING...THEREBY INCREASING THE LIFT ACROSS OUR AREA. THE
LOW CONTINUES TO LIFT NORTHEAST ACROSS NORTHERN IL THROUGH THE DAY.
TAKING A LOOK AT A CROSS SECTION OF THE MODELED ATMOSPHERE FROM
NORTH TO SOUTH ACROSS THE FORECAST AREA REVEALS BEST LIFT OCCURING
BETWEEN 9 AM AND 3 PM. IN FACT...STRONG FN VECTOR CONVERGENCE AND
-EPV SIGNALS SUGGESTING SLANTWISE-UPRIGHT CONVECTIVE BANDING ACROSS
SOUTHERN AND CENTRAL PORTIONS OF THE FORECAST AREA DURING THIS TIME
PERIOD. 2 INCH PER HOUR SNOWFALL RATES LIKELY UNDER THIS SIGNAL WITH
THE POTENTIAL OF THUNDER-SNOW. WILL STICK WITH 10-14 SNOW AMOUNTS
THROUGH THURSDAY EVENING SOUTH OF A LINE FROM ROCHESTER MN THOUGH
BLACK RIVER FALLS AND NEILSVILLE WI...TAPERING TO 6-8 NORTH OF THIS
LINE. IN ADDITION...WITH AVERAGED 15:1 SNOW:LIQUID RATIO AND AND
WINDS INCREASING INTO THE 15-25 MPH RANGE WITH HIGHER GUSTS...AREA
WILL SEE SOME SUBSTANTIAL BLOWING AROUND OF THE SNOW BY THURSDAY
AFTERNOON...LASTING THROUGH THURSDAY EVENING AS THE SNOWFALL TAPERS
OFF WITH THE LOW SHIFTING EAST.

FOCUS THEN SHIFTS TO THE ARCTIC AIR INTRUSION BEHIND THE LOW
FRIDAY THROUGH SATURDAY. COLDEST CORE OF 1000-900MB TEMPERATURES
(-25 TO -30C) INVADES THE REGION EARLY SATURDAY MORNING AS ARCTIC
HIGH MOVES OVERHEAD. HIGHS ON FRIDAY ONLY EXPECTED TO CLIMB INTO THE
SINGLE DIGITS WITH FRIDAY OVERNIGHT LOWS DIPPING INTO THE -6 TO -12F
RANGE. THE ARCTIC HIGH BEGINS TO SLIP INTO THE OHIO RIVER VALLEY
LATE SATURDAY WITH RETURN FLOW BEGINNING ACROSS THE AREA.
HOWEVER...DEEP SNOW PACK AND COLD START SATURDAY MORNING WILL
INHIBIT ANY SUBSTANTIAL MODERATION OF TEMPERATURES./DAS

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY

MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SUNDAY NIGHT
THROUGH MONDAY NIGHT. BOTH THE 00Z WEDNESDAY GFS AND ECMWF ARE IN
GOOD AGREEMENT WITH WEST TO NORTHWEST FLOW THROUGH PERIOD. NO MAJOR
DIFFERENCES SEEN BETWEEN BOTH MODELS THROUGH PERIOD. CONFIDENCE IN
FORECAST THROUGH PERIOD IS MODERATE. WEAK SHORTWAVE TROUGH EMBEDDED
IN NORTHWEST FLOW ALOFT MOVES QUICKLY INTO THE UPPER MIDWEST AND
GREAT LAKES REGION SUNDAY NIGHT AND INTO MONDAY. WEAK LIFT AND
MOISTURE STARVED SYSTEM WILL ALLOW FOR A SMALL CHANCE FOR SUNDAY
NIGHT INTO MONDAY.  HAVE REDUCED CHANCES OF PRECIPITATION SUNDAY
NIGHT INTO MONDAY NIGHT. ARCTIC SURFACE RIDGE BUILDS INTO THE
CENTRAL UNITED STATES AND DOMINATES REGION BY MIDDLE OF NEXT WEEK.
BOTH 00Z WEDNESDAY GFS AND ECMWF BOTH INDICATING COLD ARCTIC AIR
MASS OVER FORECAST AREA THROUGH WEDNESDAY...AS 850MB TEMPERATURES
HOVER AROUND MINUS 18 DEGREES CELSIUS BY 00Z WEDNESDAY. HAVE LOWERED
TEMPERATURES ACROSS FORECAST AREA THROUGH PERIOD./DTJ

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
     THURSDAY NIGHT FOR WIZ017-WIZ029-WIZ032-WIZ033-WIZ034-
     WIZ041-WIZ042-WIZ043-WIZ044-WIZ053-WIZ054-WIZ055-WIZ061.

MN...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
     THURSDAY NIGHT FOR MNZ079-MNZ086-MNZ087-MNZ088-MNZ094-
     MNZ095-MNZ096.

IA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
     THURSDAY NIGHT FOR IAZ008-IAZ009-IAZ010-IAZ011-IAZ018-
     IAZ019-IAZ029-IAZ030.

&&

DAS/DTJ

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE LA CROSSE WI
331 PM CST WED FEB 15 2006

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-161200-
ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE-
FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-
LA CROSSE-MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU-
VERNON-WABASHA-WINNESHIEK-WINONA-
331 PM CST WED FEB 15 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST IOWA...
SOUTHEAST MINNESOTA...AND SOUTHWEST INTO CENTRAL WISCONSIN.

.DAY ONE...TONIGHT

CLOUDS WILL CONTINUE TO THICKEN OVER THE AREA THIS EVENING...AHEAD
OF THE FIRST UPPER DISTURBANCE EJECTING OUT OF THE STORM SYSTEM
DEEPENING OVER THE CENTRAL ROCKIES. LIGHT SNOW WILL SPREAD ACROSS
MUCH OF THE AREA LATER THIS EVENING AND OVERNIGHT AS THIS
DISTURBANCE MOVES ACROSS THE REGION. AN INCH OR TWO OF ACCUMULATION
IS EXPECTED BY EARLY THURSDAY MORNING...MAINLY SOUTH OF LAKE CITY
MINNESOTA TO MONDOVI AND NEILLSVILLE WISCONSIN...AND NORTH OF
FAYETTE IOWA TO PRAIRIE DU CHIEN AND RICHLAND CENTER WISCONSIN.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A STRONG SURFACE AND UPPER LEVEL STORM SYSTEM IS EXPECTED TO BE
LOCATED OVER THE OKLAHOMA PAN-HANDLE AREA THURSDAY MORNING. AS THIS
STORM SYSTEM LIFTS TOWARD SOUTHERN LAKE MICHIGAN ON THURSDAY...A
BAND OF HEAVY SNOW NORTH OF THE TRACK OF THE LOW WILL SPREAD ACROSS
SOUTHERN MINNESOTA...NORTHERN IOWA AND MUCH OF WISCONSIN. MODERATE
TO HEAVY SNOW...FALLING AT THE RATE OF 1 TO 2 INCHES PER HOUR...IS
EXPECTED DURING THE LATE MORNING THROUGH MID AFTERNOON HOURS ON
THURSDAY. THE SNOW WILL TAPER OFF THURSDAY EVENING AS THE LOW PULLS
INTO MICHIGAN.

THROUGH THURSDAY EVENING...A SWATH OF 6 TO 10 INCHES OF SNOW IS
EXPECTED TO FALL ACROSS THE AREA...AND WILL CAUSE CONSIDERABLE
TRAVEL PROBLEMS. LOCALLY HIGHER AMOUNTS OF UP TO A FOOT ARE ALSO
POSSIBLE...ESPECIALLY EAST OF LA CROSSE INTO CENTRAL WISCONSIN.
STRONG NORTHWEST WINDS ON THE BACKSIDE OF THE LOW WILL CAUSE SOME
BLOWING AND DRIFTING SNOW THURSDAY AFTERNOON AND EVENING WHICH WILL
CREATE ADDITIONAL HAZARDOUS TRAVEL CONDITIONS. THE BLOWING AND
DRIFTING SNOW WILL MAINLY BE ACROSS THE OPEN AREAS WEST OF THE
MISSISSIPPI RIVER...AND OVER THE RIDGE-TOPS.

WINTER STORM WARNINGS ARE IN EFFECT FOR MUCH OF THE REGION STARTING
TONIGHT AND CONTINUING INTO THURSDAY NIGHT.

DURING THE WEEKEND...A VERY COLD AIR MASS WILL SETTLE OVER THE AREA.
SUB-ZERO LOWS ARE EXPECTED FRIDAY NIGHT THRU SUNDAY NIGHT...WITH
WIND CHILL VALUES OF 15 BELOW TO 25 BELOW POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED. REPORTS OF SNOWFALL AMOUNTS
AND SNOWFALL RATES WOULD BE GREATLY APPRECIATED LATER TONIGHT
THROUGH THURSDAY AND INTO THURSDAY EVENING.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

RRS/THOMPSON