Winter Storm in Wisconsin, March 12 to 13, 2006

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
602 PM CST SUN MAR 12 2006

.UPDATE...
HEAVIEST AND LARGEST BAND OF PCPN...MAINLY CONSISTING OF SNOW
ACRS SODAK AND W CNTRL MN AND TRANSITIONING TO RAIN/SNOW/SLEET
MIX IN E CNTRL MN...CURRENTLY STRETCHING FROM JUST SW OF HURON
SODAK TO WILLMAR TO NEAR HINCKLEY. THIS RGN OF PCPN MATCHES UP
WELL WITH THE 550 MB WAA AND FRONTOGENESIS PATTERNS FROM BOTH THE
21Z RUC AND THE 18Z 40-KM NAM. FOLLOWING THESE TWO MDL FCSTS AT
THIS LEVEL SHOWS A GRADUAL WEAKENING AND NEWRD MOVEMENT OF THESE
FEATURES THRU THE REMAINDER OF THE EVE. BY CONTRAST...THE WAA AND
FRONTOGENESIS FIELDS AT LOWER LEVELS /NAMELY 600 AND 700 MB/
REMAIN STRONG THRU APPROX MIDNGT ACRS CNTRL THIRD OF MN AND PARTS
OF W CNTRL WI...ALTHO A SIMILAR WEAKENING OCCURS WITH THESE
FEATURES AS WELL AFTER THIS TIME FRAME. ONE THING THAT MAY COME
INTO PLAY AFTER MIDNGT IS A FAIRLY WELL DEVELOPED S/WV TROF
EVIDENT IN WV IMAGERY IN SWRN CO ATTM. 21Z RUC TAKES THIS ACRS KS
AND INTO WRN IA BY 09Z...HOWEVER...EXTRAPOLATION OF THE
WAA/FRONTOGENESIS FIELDS AFTER 09Z SHOWS THE MAJORITY OF THIS
FORCING MISSES THE FA. NEVERTHELESS...THIS WILL HAVE TO BE
SOMETHING THAT IS WATCHED CLOSELY.

&&

.PREV DISCUSSION... /ISSUED 309 PM CST SUN MAR 12 2006/

DISCUSSION...TONIGHT THROUGH WEDNESDAY

RAPID INTENSIFICATION OF THE SURFACE CYCLONE OVER THE CENTRAL PLAINS
IS OCCURRING THIS AFTERNOON AS THE LEAD SHORTWAVE EJECTS OUT OF THE
BASE OF THE SOUTHERN ROCKIES TROUGH. NAM AND GFS ARE NOW UNANIMOUS
IN THEIR EJECTION OF THE ASSOCIATED SURFACE LOW NORTHEAST ACROSS
CENTRAL IOWA AND SOUTHERN WISCONSIN. AN IMPRESSIVE WARM AIR
ADVECTION REGIME IS BECOMING ESTABLISHED ACROSS SOUTHERN MINNESOTA
THIS AFTERNOON. THIS WARM AIR ADVECTION WILL SHIFT NORTH AND
OVERCOME MUCH OF CENTRAL MINNESOTA LATE THIS AFTERNOON AND EVENING.
DEFINITELY HAVE A PRIME SET UP FOR FORCING THIS EVENING ACROSS THE
MIDSECTION OF THE CWA...WITH A BULLSEYE OF H5-H3 Q VECTOR
CONVERGENCE PROGGED TO INTERSECT A LAYER OF NOTABLE 2D
FRONTOGENESIS. ALSO HAVE CONFIRMATION FROM GFS/NAM FORECAST
700MB-600MB -FN VECTOR DIVERGENCE AXIS...WHICH IS ORIENTED ALONG A
CANBY TO MINNEAPOLIS TO BALDWIN WISCONSIN LINE. OVER THE CENTRAL
PORTION OF THE FORECAST AREA...A CROSS SECTION SHOWS A LAYER OF NEAR
NEGATIVE TO NEGATIVE SATURATED EPV...WHICH ILLUSTRATES THE
INSTABILITY OF THIS SYSTEM. ALSO HAVE STRONG FULL WIND FRONTOGENESIS
FORECAST BELOW THIS LAYER. WITH ALL OF THESE FEATURES COMING
TOGETHER...HAVE CONFIDENCE A SWATH OF HEAVY SNOW WILL BISECT THE
FORECAST AREA...WITH FORCING AND INSTABILITY PARAMETERS POINTING TO
POTENTIAL FOR 1-2 INCH PER HOUR ACCUMULATIONS.

WILL LIKELY SEE A BRIEF SNOW-FREE PERIOD LATE THIS AFTERNOON AND
EVENING ACROSS SOUTH CENTRAL MINNESOTA...WHERE BOTH 12Z/18Z RUNS ARE
INDICATING A DRY SLOT WILL SURGE NORTHEAST IN ADVANCE OF THE 700 MB
LOW. THIS SHOULD FILL BACK IN WITH SNOW AFTER 06Z TONIGHT AS THE LOW
SHIFTS EAST AND A DEFORMATION AXIS SETS UP FROM SOUTHWEST TO
NORTHEAST ACROSS THE MID PORTION OF THE CWA. ALSO SEEING STRONG
PACKING OF THE -10C TO -12C ISOTHERMS AT 700 MB. HAVE PLACED A BAND
OF 6-10 INCH STORM TOTALS FROM GRANITE FALLS...THROUGH THE TWIN
CITIES...TO RICE LAKE WISCONSIN. THIS IS SUPPORTED BY THE
AFOREMENTIONED INTENSE FORCING...WHICH COMBINE WITH SPECIFIC
HUMIDITIES OF 2-3 G/KG DURING A 6-12 HOUR PERIOD OF LIFT. THE COBB
METHOD IS YIELDING OVER 12 INCHES FOR A GOOD PORTION OF THE WARNING
AREA...BUT BELIEVE IT IS ON THE HIGH SIDE DUE TO ITS INFLATED SNOW
RATIOS.

HAVE EXPANDED THE WARNING SLIGHTLY FARTHER NORTH TO CATCH THE
NORTHERN PORTION OF THE DEVELOPING DEFORMATION ZONE. HAVE ALSO
CHANGED IT TO A WINTER WEATHER WARNING DUE TO THE ANTICIPATED
EFFECTS OF INCREASING NORTHERLY WINDS...WHICH WILL ENTER THE BRISK
CATEGORY OVERNIGHT...AND LIKELY LEAD TO BLOWING AND DRIFTING. BOTH
NORTHWEST AND SOUTHEAST FRINGES OF THE FORECAST AREA HAVE BEEN
INCLUDED IN WINTER WEATHER ADVISORIES...WHERE SLIGHTLY LESSER
SNOWFALL AMOUNTS IN THE 3 TO 5 INCH RANGE ARE ANTICIPATED.

WITH THE 700MB LOW STILL FORECAST TO BE CENTERED ACROSS THE EASTERN
HALF OF THE FORECAST AREA AT 12Z MONDAY...HAVE EXTENDED THE WINTER
WEATHER PRODUCTS UP TO 18Z. THIS SHOULD ALSO COVER ANY
BLOWING/DRIFTING THAT OCCURS DURING THE MORNING.

LONGER TERM...WEDNESDAY NIGHT THROUGH SUNDAY

POTENTIAL FOR ANOTHER ROUND OF SNOW ACROSS THE CWA WEDNESDAY NIGHT
AND EARLY THURSDAY. GFS AND ECMWF ARE PRETTY MUCH ON THE SAME PAGE
WITH THE MOVEMENT OF THE SURFACE LOW ACROSS IA WITH THE GFS A LITTLE
FASTER. WILL HAVE POPS IN THE 30 TO 50 PERCENT RANGE NORTH TO SOUTH.
A DRY PERIOD THEN ANTICIPATED LATE THURSDAY INTO SATURDAY WITH
SEASONAL TEMPERATURES. NEXT WEATHER MAKERS POTENTIAL ARRIVES INTO
THE CWA ON SUNDAY BUT VERY DIFFERENT SOLUTIONS HAVE EVOLVED BY THEN
BETWEEN THE ECMWF AND GFS AND WILL KEEP THE COLLABORATED POPS IN
PLACE.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR ANOKA-BENTON-
     BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-GOODHUE-
     HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-
     MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-RAMSEY-
     REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-SWIFT-
     WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE COUNTY(IES).

     WINTER WEATHER ADVISORY UNTIL 12 PM CST MONDAY FOR DOUGLAS-
     FARIBAULT-FREEBORN-POPE-STEELE-STEVENS-TODD-WASECA
     COUNTY(IES).

WI...WINTER STORM WARNING UNTIL 12 PM CST MONDAY FOR BARRON-CHIPPEWA-
     DUNN-PIERCE-POLK-RUSK-ST. CROIX COUNTY(IES).

     WINTER WEATHER ADVISORY UNTIL 12 PM CST MONDAY FOR EAU CLAIRE-
     PEPIN COUNTY(IES).

&&

KAT/SCHMIT/RAH

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
239 PM CST SUN MAR 12 2006

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-131200-
ANOKA-BARRON-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-
DOUGLAS-DUNN-EAU CLAIRE-FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-
KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-
MILLE LACS-MORRISON-NICOLLET-PEPIN-PIERCE-POLK-POPE-RAMSEY-REDWOOD-
RENVILLE-RICE-RUSK-SCOTT-SHERBURNE-SIBLEY-ST CROIX-STEARNS-STEELE-
STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE-
239 PM CST SUN MAR 12 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SNOW ACROSS SOUTHERN MINNESOTA WILL SPREAD NORTHWARD ACROSS
CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN DURING THE REMAINDER
OF THE AFTERNOON AND EARLY EVENING. HEAVY SNOW ACCUMULATIONS OF 6
TO 9 INCHES ARE EXPECTED TONIGHT FROM MADISON...REDWOOD FALLS AND
FAIRMONT ON NORTHEAST THROUGH ST CLOUD...LITTLE FALLS...THE TWIN
CITIES...CAMBRIDGE...MORA...AS WELL AS...ELLSWORTH...MENOMONIE...
BALSAM LAKE...RICE LAKE AND LADYSMITH IN WEST CENTRAL WISCONSIN. IN
ADDITION TO THE SNOW...BRISK NORTHERLY WINDS WILL DEVELOP TONIGHT
CAUSING BLOWING AND DRIFTING SNOW.

THREE TO 6 INCHES OF SNOW ARE EXPECTED IN THE MORRIS AND
ALEXANDRIA AREAS TONIGHT AS WELL AS FROM BLUE EARTH AND ALBERT LEA
ON NORTHEAST THROUGH EAU CLAIRE. THERE WILL ALSO BE INCREASING
NORTHERLY WINDS IN THESE AREAS OVERNIGHT WITH SOME BLOWING AND
DRIFTING SNOW.

SEE THE LATEST WINTER WEATHER MESSAGE FROM THE CHANHASSEN/TWIN CITIES
NATIONAL WEATHER SERVICE OFFICE FOR SPECIFIC DETAILS ON THE WINTER
STORM WARNINGS AND ADVISORIES COVERING CENTRAL AND SOUTHERN MINNESOTA
AND WEST CENTRAL WISCONSIN.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SNOW AND BRISK NORTHERLY WINDS WILL CONTINUE EARLY MONDAY THEN
SUBSIDE IN THE AFTERNOON. ADDITIONAL SNOW ACCUMULATIONS ARE LIKELY
EARLY MONDAY...ESPECIALLY OVER EAST CENTRAL MINNESOTA AND WEST
CENTRAL WISCONSIN. THIS WILL MEAN THAT A FEW LOCATIONS WILL LIKELY
END UP WITH AROUND A FOOT OF SNOW.

ANOTHER STRONG WEATHER SYSTEM IS EXPECTED TO BRING MORE SNOW TO
THE REGION FROM WEDNESDAY INTO THURSDAY MORNING. KEEP UP ON THE
LATEST FORECAST CONCERNING THIS WEATHER SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS AND SNOWFALL OBSERVERS ARE HIGHLY ENCOURAGED TO CALL
IN THEIR SNOWFALL AMOUNTS.

RAH