FXUS63 KDLH 090544
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1144 PM CST TUE DEC 8 2009
.AVIATION...06Z TAFS.
NO REAL CHANGE FROM PRIOR AVIATION DISCUSSION FOR ALL TAF SITES
EXCEPT KHYR. SOME IFR CONDITIONS AT KHYR WITH OCCASIONAL LIFR IN
HEAVIER SNOW BANDS THROUGH 18Z.
&&
.PREV DISCUSSION... /ISSUED 940 PM CST TUE DEC 8 2009/
UPDATE...ADJUSTMENTS MADE TO EVENING SNOW AS A 6 INCH REPORT
ALREADY RECEIVED FROM BAYFIELD COUNTY S OF CORNUCOPIA. LES BANDS
CONTINUE FROM JUST E OF SUPERIOR WI ALONG THE SHORE TO PORT WING.
ANOTHER BAND FROM WASHBURN TO NEAR IRON RIVER WI. MASSAGED TEMPS A
BIT IN MOST LOCATIONS. REST OF THE FORECAST UNCHANGED.
PREV DISCUSSION... /ISSUED 658 PM CST TUE DEC 8 2009/
AVIATION...00Z TAFS.
CIGS WILL DROP FROM VFR NEAR THE CANADIAN BORDER TO MVFR FROM KBRD
TO KHYR. HEAVIEST SNOW WILL BE NEAR THE SOUTH SHORE OF LAKE
SUPERIOR WHERE LAKE EFFECT BANDS NEAR KSUW AND KASX WILL CONTINUE.
LOOK FOR THE MVFR TO OVERSPREAD THE REST OF NE MN WITH IFR
EVENTUALLY REACHING NW WI TO EAST CENTRAL MN BETWEEN 03 AND 06Z.
PREV DISCUSSION... /ISSUED 402 PM CST TUE DEC 8 2009/
SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...
MAJOR WINTER STORM IS BEGINNING TO PRODUCE ACCUMULATING SNOW
ACROSS THE FORECAST AREA LATE THIS AFTERNOON...MAINLY SOUTH OF A
BRAINERD TO DULUTH LINE AS OF 330 PM. IN ADDITION..TWO LAKE EFFECT
BANDS HAVE ALSO FINALLY SPREAD ONSHORE..AFFECTING HIGHWAYS 2/53
JUST EAST OF SUPERIOR..AND BAYFIELD/ASHLAND.
THE INITIAL SNOW IS ASSOCIATED WITH A LEAD IMPULSE OUT AHEAD OF
THE PRIMARY UPPER LEVEL WAVE NOW COMING ACROSS WRN KANSAS. LATEST
MODEL GUIDANCE HAS CLOSED TO A SOLUTION BRINGING THE MAIN SURFACE
LOW FROM JUST SOUTHEAST OF KANSAS CITY TO SOUTHERN LAKE MICHIGAN
BY WED MORNING. THIS SOLUTION IS SLIGHTLY TO THE WEST OF PREVIOUS
GUIDANCE..BUT RESULTS IN THE NEED FOR FEW CHANGES TO THE GOING
FORECAST.
SNOW WILL CONTINUE TO INCREASE IN INTENSITY ACROSS TH SRN CWA THIS
EVENING..AND SPREAD NEWD ACROSS THE REMAINDER OF THE AREA
OVERNIGHT. A BAND OF 3-6 INCHES OF FLUFFY ACCUMS IS EXPECTED FROM
BRAINERD..TO COTTON AND THE BOUNDARY WATERS..WITH 6-9 INCHES
ACROSS THE I35/HIGHWAY 61 CORRIDOR IN MINNESOTA. A GENERAL 8-12 IS
EXPECTED OVER NW WI..WITH 12-18 TOTALS IN THE LAKE EFFECT AREAS OF
THE SOUTH SHORE.
EXCEPTIONALLY COLD AIR MASS FOR SUCH A BIG SNOW EVENT WILL ALSO
RESULT IN INCREASED DENDRITIC GROWTH AND SNOW EFFICIENCY..DESPITE
MUCH OF THE DULUTH CWA BEING REMOVED RATHER FAR TO THE NW FROM THE
PATH OF THE SFC LOW.
SNOW SHUD DIMINISH TO FLURRIES FROM WEST TO EAST BEGINNING MIDDAY
WED OUT WEST AND MOST OTHER AREAS BY LATE WED AFTERNOON. EXCEPTION
WILL BE THE LAKE EFFECT ZONES WHERE WINTER STORM CONDITIONS WILL
PERSIST FOR MUCH OF WED NIGHT.
HAVE LOWERED TEMPS WED NIGHT/THUR RATHER CONSIDERABLY FROM PREVIOUS
FORECAST IN LINE WITH NEW GUIDANCE AND FRESH SNOW COVER. TEMPS IN
THE MINUS SINGLE DIGITS AND TEENS WILL COMBINE WITH DIMINISHING
NORTHWEST/WEST WINDS TO PRODUCE WIND CHILLS IN THE MINUS 20S AND
30S THURS MORNING AND WE MAY NEED A WIND CHILL ADVISORY FOR THIS
TIME FRAME.
LONG TERM...THURSDAY THROUGH TUESDAY...
EARLY PART OF THE EXTENDED WILL BE RELATIVELY QUIET...BUT COLD AS
THE CWA REMAINS SOUTH OF AN UPPER LOW. THE GFS AND ECMWF QUICKLY
DIVERGE BY FRIDAY-SATURDAY. THE ECMWF IS MUCH FURTHER NORTH WITH THE
UPPER LOW...PLACING IT IN NORTHERN SK...WHERE THE GFS IS FURTHER
SOUTH IN SOUTHERN MB. A WEAK LOW WILL SLIDE THROUGH THE NORTHLAND
FRIDAY NIGHT INTO SATURDAY. WE HAVE SMALL POPS FOR THAT FEATURE
ATTM...BUT WILL HAVE TO WATCH CLOSELY FOR AN INCREASE AS A DECENT
THERMAL GRADIENT EXISTS.
BIG DIFFERENCES IN THE MODELS CONTINUE SATURDAY NIGHT INTO
SUNDAY...WITH THE GFS FORECASTING MUCH COLDER TEMPERATURES. NO MAJOR
STORMS FOR THE REST OF THE EXTENDED...WITH TEMPS AT OR BELOW NORMAL.
AVIATION...12/08 18Z TAF ISSUANCE
LOW PRESSURE WILL BE MOVING THROUGH THE SOUTHERN PLAINS...THEN
HEAD NORTH TOWARD SOUTHERN LAKE MICHIGAN BY WEDNESDAY MORNING. THE
LOW WILL CONTINUE NORTHEAST DURING THE DAY WEDNESDAY. SNOW WILL BE
SPREADING NORTH THROUGH MUCH OF THE NORTHLAND...REACHING THE
BORDER COUNTRY LATE THIS EVENING. THE SNOW WAS ALREADY SPREADING
THROUGH CENTRAL MINNESOTA AND INTO NORTHERN WISCONSIN. VSBYS WILL
BE DROPPING TO 1 TO 3 MILES...THEN EVENTUALLY TO A HALF TO A MILE
FOR THE KBRD TO KDLH TO KBFW AREAS AND POINTS SOUTHEAST. IFR OR
LOW MVFR CONDITIONS WILL BE THE RULE TONIGHT INTO WEDNESDAY FOR
MOST AREAS...EXCEPT FOR THE FAR NORTHWEST. WINDS WILL BE
INCREASING AS WELL...ESPECIALLY AROUND LAKE SUPERIOR. BLOWING SNOW
WILL BE AN ISSUE.
MARINE...
LOW PRESSURE WILL INTENSIFY SIGNIFICANTLY TONIGHT AND WEDNESDAY
WHILE MOVING FROM KANSAS TO SOUTHERN LAKE MICHIGAN. A VERY STRONG
NORTHERLY PRESSURE GRADIENT WILL DEVELOP ACROSS WESTERN LAKE
SUPERIOR TONIGHT/WEDNESDAY/WEDNESDAY NIGHT. IN ADDITION..VERY COLD
ARCTIC AIR IN PLACE AND STILL WARM WATER TEMPS FROM 40-44 DEGREES
FAHRENHEIT WILL RESULT IN UNSTABLE CONDITIONS AND VERY STRONG
GALE FORCE NORTH WINDS ACROSS ALL OF WESTERN LAKE SUPERIOR. THE
PEAK OF THE STORM IS EXPECTED FROM EARLY WEDNESDAY MORNING INTO
WEDNESDAY NIGHT WITH SUSTAINED NORTH WINDS FROM 30-40 KNOTS AND
GUSTS TO 55 KNOTS.
&&
.POINT TEMPS/POPS...
DLH 4 11 -6 7 / 100 100 10 10
INL -3 3 -14 0 / 70 60 10 10
BRD 1 7 -9 6 / 100 80 10 10
HYR 11 17 -4 5 / 100 100 30 10
ASX 12 20 3 8 / 100 100 70 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
MNZ012-019-034>036.
WINTER STORM WARNING UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
MNZ020-021-037-038.
WI...WINTER STORM WARNING UNTIL MIDNIGHT CST WEDNESDAY NIGHT FOR
WIZ006>009.
WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR WIZ001>004.
LS...SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 PM CST THURSDAY
FOR LSZ121-140>148.
GALE WARNING UNTIL 6 PM CST WEDNESDAY FOR LSZ121-140>148.
&&
$$
GSF/GSF/GSF
