FXUS63 KDLH 241052
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
452 AM CST THU DEC 24 2009
.DISCUSSION...WINTER STORM/BLIZZARD IS THE MAIN FOCUS TODAY.
QUITE A MORNING ACROSS THE NORTHLAND...AS THE FIRST BATCH OF SNOW
LIFTS RAPIDLY THROUGH THE CWA. SNOW CONTINUED TO COME DOWN HARD AS
OF 430 AM...WITH SEVERAL WAVES OF SNOW REPLENISHING AS THEY LIFT
TO THE NORTH. A COMBINATION OF THREE DISTINCT VORT MAXES LIFTING
INTO THE EASTERN DAKOTAS AND MINNESOTA WAS TAPPING INTO A DEEP
MOISTURE PLUME/CONVEYOR BELT LIFTING INTO MN FROM THE WESTERN GULF
OF MEXICO. THE RESULT WAS BROAD...LARGE SCALE DIVERGENCE AND
PERSISTENT SNOWFALL. SNOWFALL AMOUNTS WERE PRETTY MINIMAL DURING
THE EARLY MORNING...BUT SO FAR WE HAVE HAD ABOUT 3 INCHES AT OUR
OFFICE. WHILE THERE WAS A DISCRETE BREAK IN THE SNOW BANDS...MORE
CONVECTIVE LOOKING SNOWFALL WAS LIFTING THROUGH THE TWIN CITIES AT
THIS TIME. SOME SNOWFALL RATES THIS MORNING HAVE BEEN CLOSE TO AN
INCH AN HOUR...BUT LOCAL RATES OF MORE THAN AN INCH AN HOUR COULD
OCCUR IF THE MORE CONVECTIVE PRECIPITATION HOLDS TOGETHER AS
EXPECTED. THE SNOW SHOULD GRADUALLY DIMINISH SOMEWHAT AS THE
MORNING WEARS ON...AND WE FEEL THERE WILL MAY BE A LET UP IN THE
HEAVIER SNOWFALL RATES TOWARD MIDDAY FOR MANY AREAS. WINDS NEAR
LAKE SUPERIOR HAVE BEEN FAIRLY STRONG THIS MORNING...BUT WE SHOULD
SEE A DIMINISHING TREND WITH REGARD TO WINDS ON LAKE SUPERIOR
DURING THE DAY AS WELL.
MANY AREAS ARE EXPECTED TO RECEIVE BETWEEN 4 AND 8 INCHES BY MID
TO LATE AFTERNOON. BASED ON THE NATURE OF THE EXPECTED CONVECTIVE
SNOW BURSTS THAT MAY BE LIFTING UP INTO THE AREA THIS
MORNING...AMOUNTS COULD BE HIGHLY VARIABLE. WE COULD SEE SOME
AMOUNTS ALREADY EXCEEDING 8 INCHES BY LATE AFTERNOON. THE MOST
LIKELY AREAS WOULD BE FROM EAST CENTRAL MINNESOTA AND FAR NW
WI...INTO THE TWIN PORTS AND THE NORTH SHORE. STRONG EASTERLY
WINDS...FORCED UP THE SAWTOOTH RANGE ON THE NORTH SHORE WILL
CERTAINLY CONTRIBUTE TO HIGHER AMOUNTS IN THE HIGHER TERRAIN NEAR
LAKE SUPERIOR.
WHILE THE HEAVY SNOWFALL TODAY WILL DEFINITELY BE A BIG
STORY...AN EVEN BIGGER STORY WILL BE THE DEVELOPMENT OF A FULL
FLEDGED BLIZZARD ACROSS THE WESTERN TIP OF LAKE SUPERIOR TONIGHT
AND ON CHRISTMAS DAY. AS THE NORTHERN AND SOUTHERN STREAM UPPER
LOWS PHASE OVER IOWA TONIGHT...THE COMBINED STORM IS EXPECTED TO
STRENGTHEN. THE STRENGTHENING LOW PRESSURE SYSTEM WILL BRING AN
INCREASED ISALLOBARIC COMPONENT DOWN THE LONG PORTION OF THE LAKE.
HAVE INCREASED WINDS NEAR LAKE SUPERIOR TO 30 TO 40 MPH...AND
MENTIONED SOME 50 MPH WIND GUSTS POSSIBLE AT THE HEAD OF THE
LAKES. WE STRONGLY FEEL THAT TRAVEL WILL BE NEARLY IMPOSSIBLE FROM
MIDNIGHT TONIGHT INTO CHRISTMAS DAY AND POSSIBLY CHRISTMAS NIGHT
AT THE HEAD OF THE LAKES. THE ONE MAJOR CONCERN IS THE POTENTIAL
FOR PEOPLE TO LET THEIR GUARD DOWN IF THERE IS A LULL IN THE
PRECIPITATION AND STRONG WINDS DURING THE DAY TODAY. FOR THIS
REASON...WE HAVE STRONGLY DETAILED THE MENTION OF TWO DISTINCT
PHASES OF THIS STORM...THE BATCH MOVING THROUGH THIS MORNING...AND
THE NEXT MAJOR BATCH MOVING THROUGH TONIGHT WITH INTENSE EAST
WINDS. WE FEEL THAT WHITEOUT CONDITIONS WILL BE LIKELY BY MIDNIGHT
TONIGHT...CONTINUING INTO AT LEAST CHRISTMAS DAY.
THE MODELS ARE GENERALLY IN GOOD AGREEMENT...WITH MODEL QPF
RANGING FROM 1.25 INCHES FOR DULUTH THROUGH SATURDAY MORNING...TO
AROUND 2.5 INCHES ON THE NAM. THE ECMWF IS CLOSE TO 1.50 INCHES.
WILL CONTINUE WITH GOING TOTAL SNOWFALL AMOUNTS...WITH A GRAND
TOTAL OF MORE THAN 20 INCHES POSSIBLE ALONG THE NORTH SHORE. MUCH
OF THE REST OF THE AREA WILL SEE A FOOT OF SNOW OR BETTER AS WELL.
THE ONLY PLACES EXPECTED TO SEE A BIT LESS ARE IN PORTIONS OF NW
WI...WHICH MAY SEE SOMEWHAT LOWER AMOUNTS DUE TO SOME SLEET OR
FREEZING RAIN MIXING IN FOR A TIME.
THE UPPER LOW WILL THEN PINWHEEL THROUGH THE WESTERN GREAT LAKES
FOR MUCH OF THE WEEKEND...BEFORE GRADUALLY PUSHING OFF BY EARLY
NEXT WEEK. THINGS WILL QUIET DOWN CONSIDERABLY BY NEXT WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
SNOW HAS MOVED INTO NW WI...AND MUCH OF CTR MN AS OF 6Z. CIGS AND
VSBYS QUICKLY DROP TO THE IFR AND LIFR RANGE FROM SOUTH TO NORTH...AS
MAJOR WINTER STORM BEGINS TO AFFECT THE REGION. THE SNOW WILL BE
HEAVIEST IN THE EARLY MORNING HOURS...WITH A BREAK LATE THUR
MORNING INTO THE AFTERNOON...BEFORE ANOTHER ROUND OF HEAVIER SNOW
MOVES INTO NE MN AND NW WI AROUND 00Z FRI. WINDS WILL BE NORTHEAST
AND GUSTY...ESP AT KDLH WHERE BLSN IS LIKELY THROUGH MUCH OF THE
TAF PD.
&&
.POINT TEMPS/POPS...
DLH 30 28 30 17 / 100 100 100 90
INL 26 24 25 14 / 100 100 100 90
BRD 28 26 29 17 / 100 100 100 90
HYR 31 30 33 20 / 100 100 100 70
ASX 32 30 32 19 / 100 100 100 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 6 AM CST SATURDAY FOR MNZ010>012-018-
019-021-025-026-033>036-038.
BLIZZARD WARNING UNTIL 6 AM CST SATURDAY FOR MNZ020-037.
WI...WINTER STORM WARNING UNTIL 6 AM CST SATURDAY FOR WIZ002>004-
006>009.
BLIZZARD WARNING UNTIL 6 AM CST SATURDAY FOR WIZ001.
LS...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LSZ121-
140>148.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM CST FRIDAY FOR
LSZ121-140>148.
&&
$$
DAP/GRANING/GRANING
