FXUS63 KDLH 080204
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
804 PM CST MON DEC 7 2009
.UPDATE...SNOW SHOWERS HAVE FORMED OVER NE DOUGLAS COUNTY AND THE
BAYFIELD PENINSULA THANKS TO NW FLOW OVER LAKE SUPERIOR AND LOW
LEVEL CONVERGENCE. THESE SNOW SHOWERS WILL DIMINISH AS THE EVENING
PROGRESSES AS THE WIND BECOMES WESTERLY. ADJUSTED MIN TEMPS WHERE
NEEDED AS LACK OF CLOUD COVER ACROSS THE NORTHERN HALF OF THE FA
HAS ALLOWED TEMPS TO DROP BELOW PREVIOUS FORECAST MIN TEMP RANGE.
ALSO TWEAKED WIND AND SKY COVER.
&&
.PREV DISCUSSION... /ISSUED 612 PM CST MON DEC 7 2009/
AVIATION...00Z TAFS.
AS HIGH PRESSURE BUILDS INTO NE MN AND NW WI...SOME CLEARING HAS
OCCURRED EXCEPT AT KBRD AND KHYR WHERE SOME CLOUDS LINGER. VFR
WILL GIVE WAY TO MVFR BY 18Z AT KBRD AND KHYR...20Z AND LATER
ELSEWHERE. APPEARS THE SNOW WILL HOLD OFF UNTIL THEN.
PREV DISCUSSION... /ISSUED 243 PM CST MON DEC 7 2009/
FIRST MAJOR WINTER STORM TO AFFECT NORTHLAND...
DISCUSSION...CONCERN FOR SHORT TERM IS WINTER STORM TUESDAY AND
WEDNESDAY WITH LAKE EFFECT SNOW IN NW WI WED NIGHT AND THU. LONG
TERM CONCERN IS VERY COLD AIR PUSHING INTO REGION.
CURRENT SURFACE ANALYSIS AND WEB CAMS INDICATE SNOW SHOWERS STILL
FALLING ALONG SNOW BELT AREAS IN NW WI BUT ARE TAPERING OFF. THE
SNOW WILL END BY THIS EVENING AS THE WINDS CONTINUE TO SWITCH TO
THE NORTHWEST. THE REST OF THE AREA ONLY SEES LIGHT SNOW/
THERE WILL BE A BREAK TONIGHT ACROSS THE REGION BEFORE THE MAIN
SHOW COMES IN TUESDAY. MODELS HAVE DIFFERENT SOLUTIONS TO MOVEMENT
OF SYSTEM OVER NEXT 48 HOURS. NAM HAS LOW CENTER EAST OF MKC 00Z
WED...CENTRAL LAKE MICHIGAN 12Z WED...AND NEAR SSM 18Z WED. THE
GFS AND ECMWF HAS LOW PRESSURE NEAR KS-OK BORDER AT 00Z WED...NEAR
CHI AT 12Z WED AND IN THE EASTERN LAKE HURON BY 18Z WED. THE
ENSEMBLES ALSO LEAN TOWARD THIS SOLUTION. WILL GO WITH THIS
SOLUTION FOR FCST BASED ON RECENT PERFORMANCE AND NCEP AND LOCAL
DISCUSSIONS. WILL UPGRADE WATCH AREA TO WARNING AND ADD WINTER
WEATHER ADVISORY TO AITKIN COUNTY. IT LOOKS LIKE BEST SNOW FALL
WILL BE ACROSS NW WI COUNTIES. BASED ON FRONTOGENESIS...MOISTURE
CONTENT...AND FORECAST MOVEMENT OF SYSTEM...SYNOPTIC SNOW WILL
BEGIN SPREADING INTO FORECAST AREA FROM SOUTH TUESDAY AFTERNOON.
THE LOW WILL DEEPEN RAPIDLY AS IT MOVES NORTHEAST TUESDAY NIGHT
AND WEDNESDAY. THE BEST FRONTOGENESIS WILL DEVELOP TUE EVENING AND
CONTINUE INTO WED MORNING ACROSS THE WARNING AREA WHICH WILL
DEVELOP THE HEAVIEST SNOWFALL ACROSS THAT AREA.
THE HEAVY SNOW WILL END RAPIDLY ACROSS THE IRON RANGE AND THE
INLAND AREAS OF THE ARROWHEAD AS THE UPLIFT DECREASES. WINDS WILL
INCREASE OFF LAKE SUPERIOR EARLY WED MORNING AND CONTINUE TO
REMAIN WINDY DURING THE DAY. THE MAJOR PORTION OF THE SYNOPTIC SNOW
WILL CONTINUE ACROSS NW WI ON WEDNESDAY. LAKE EFFECT SNOW WILL
BEGIN LATE WEDNESDAY AND CONTINUE INTO EARLY THURSDAY AS THE MUCH
COLDER AIR FLOWS ACROSS THE LAKE.
SNOWFALL AMOUNTS WILL RANGE FROM 3-5 INCHES IN AITKIN COUNTY...4-8
INCHES ACROSS IRON RANGE AND ARROWHEAD...8-12 INCHES ACROSS TWIN
PORTS AND NORTH SHORE...9-14 INCHES IN NW WI EXCLUDING THE SOUTH
SHORE. ALONG THE SOUTH SHORE OF THE LAKE...AMOUNTS WILL RANGE FROM
12-18 INCHES ESPECIALLY ALONG THE GOGEBIC RANGE.
MUCH COLDER AIR PUSHES INTO THE FORECAST AREA WEDNESDAY NIGHT AND
THURSDAY AND CONTINUE INTO THE END OF THE WEEK.
EXTENDED...EXTENDED...THUR NIGHT THROUGH MONDAY...
COLD WEATHER EXPECTED AS LARGE POLAR VORTEX EXPANDS SOUTHWARD FROM
NORTHWEST TERRITORIES. INITIAL SFC SYSTEM OVER ERN GT LAKES WILL
PULL FIRST DOSE OF FRESH ARCTIC AIR SOUTH INTO CWA. FRIDAY MAY SEE
SOME MODERATION IN TEMPS BEFORE MORE SIGNIFICANT POOL OF ARCTIC AIR
ARRIVES FOR THE WEEKEND. SHOULD SEE SOME REDEVELOPMENT OF LES ALONG
ERN WISC SNOWBELT DURING THE WEEKEND. SHOULD SEE COLDEST MIN TEMPS
THIS SEASON SOMETIME THIS WEEKEND/EARLY NEXT WEEK.
AVIATION...18Z TAF ISSUANCE...
MAINLY MVFR/LOW VFR THIS PERIOD AS CLOUDS REMAIN ACROSS CWA TODAY
WITHIN COLD AIR. COND PRESS DEFICITS HINT THAT SOME LOWERING OF THE
CEILING WILL CONTINUE TO OCCUR NEAR BRD THIS
AFTERNOON/EVENING..MAY AFFECT DLH/HYR OVERNIGHT/EARLY TUESDAY.
OTHERWISE...DETERIORATING CONDITIONS WILL DEVELOP TUESDAY
AFTERNOON AT SRN TERMINALS.
&&
.POINT TEMPS/POPS...
DLH 1 20 8 17 / 10 80 100 100
INL -7 12 -2 9 / 10 30 30 30
BRD 4 16 6 10 / 10 70 70 40
HYR 8 22 16 19 / 10 70 100 100
ASX 11 23 19 22 / 70 70 100 100
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING FROM NOON TUESDAY TO 6 AM CST THURSDAY FOR
MNZ012-019>021-037-038.
WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 6 PM CST WEDNESDAY
FOR MNZ035-036.
WI...WINTER STORM WARNING FROM NOON TUESDAY TO 6 AM CST THURSDAY FOR
WIZ001>004-006>009.
LS...SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 PM CST THURSDAY FOR
LSZ121-140>148.
&&
$$
GSF
