FXUS63 KDLH 300328
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
927 PM CST SUN NOV 29 2009
.DISCUSSION...
UPDATED GRIDS TO DIMINISH WINDS TONIGHT OVER LAND...AND INCREASE
SOME OVER LAKE SUPERIOR. WE ALSO INCREASED SKY COVER FOR MOST
AREAS...AS THE CLEARING LINE IS MOVING SLOWLY WEST TO EAST.
WE ALSO INCREASED POPS SOME ON MONDAY DUE TO SOME FORECAST
FGEN/WAA. LATEST NAM HIGHLIGHTS OUR EASTERN AREAS IN THE AFTERNOON
WITH QPF TO A TENTH OF AN INCH IN SPOTS.
&&
.PREV DISCUSSION... /ISSUED 535 PM CST SUN NOV 29 2009/
AVIATION...FOR 00Z NOV 30TH TAFS
A DECK OF CLOUDS...WITH MOST BASES BETWEEN 2500-3500 FEET COVERED
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN. THERE WERE A FEW
POCKETS OF LOWER CEILINGS AROUND 1500FT. THE CLOUD WAS ERODING FROM
THE NORTHWEST...AND KINL WILL SCATTER OUT THIS EVENING AS SURFACE
RIDGING MOVES IN. THE CLOUD WILL BE SLOW TO ERODE ELSEWHERE. ANOTHER
AREA OF LOW PRESSURE WILL QUICKLY MOVE IN ON MONDAY...AND SPREAD AN
AREA OF FLURRIES OR LIGHT SNOW ACROSS MAINLY NORTHERN AREAS. THERE
COULD BE A NARROW BAND OF HEAVIER SNOW THAT TRANSLATES THROUGH THE
NORTHLAND...BUT AT THIS TIME...IT TOO DIFFICULT TO TELL WHERE THIS
BAND WILL SET UP.
PREV DISCUSSION... /ISSUED 345 PM CST SUN NOV 29 2009/
DISCUSSION...
PACIFIC AIR IS STILL WITH US...RIDGING SHOULD END ANY LEFT-OVER
SNOW SHOWERS THIS EVENING...BUT WILL DO LITTLE TO REMOVE CLOUDS
TONIGHT. WARM AIR WILL RETURN...FIRST WITH A SHOT OF VERY LIGHT
WET SNOW OR A MIX...THEN RISING TEMPERATURES MONDAY. A SHORT SHOT
OF FRONTOGENESIS THE MIDDLE OF MONDAY AFTERNOON MAY ENHANCE SNOW
SOUTH OF THE GOGEBIC RANGE...BUT THE EXISTENCE OF THAT SHORT-LIVED
STRUCTURE IS STILL IN DOUBT. CONTINUED WARMING WILL OCCUR AT
LOWER LEVELS...WITH THE PRECIPITATION TO OUR EAST AND TEMPERATURES
KEPT FROM FALLING VERY FAR MONDAY NIGHT. THERE SHOULD BE SOME
PRETTY GOOD WARMING AHEAD OF A RAPIDLY DEEPENING STORM TUESDAY.
RAIN AND SNOW SHOWERS WILL LIKELY BE CONFINED TO THE CANADIAN
BORDER...WITH A PRETTY DECENT SNOWSTORM TO THE NORTH. THE COLD
FRONT WITH THIS LOW SHOULD ONCE AND FOR ALL REMOVE PACIFIC AIR
FROM OUR AREA AS IT SCOOTS THROUGH TUESDAY EVENING. ALL THE RECENT
MODEL RUNS AGREE VERY CLOSELY ON THIS WHOLE SCENARIO. BEHIND THE
FRONT...THERE IS A RISK OF QUITE A WINDSTORM LATE TUESDAY NIGHT
AND WEDNESDAY. EVEN AS THE VERY TIGHT GRADIENT AND ISALLOBARIC
VECTORS SUBSIDE...A DEEP AND STEEP LAPSE RATE WILL KEEP THE WINDS
QUITE STRONG AS MOMENTUM TRANSFER WITH HIGHER AND HIGHER LEVELS
CONTINUES LATE WEDNESDAY AND WEDNESDAY EVENING. AGAIN...ALL THIS
WILL RESULT IN VERY LITTLE PRECIPITATION ACROSS OUR AREA. THE
COOLING ALOFT WILL BE MORE DRAMATIC THAN AT THE SURFACE LATE
TUESDAY NIGHT AND WEDNESDAY...AND WITH THE PACIFIC AIR REMOVED...A
LONG IMPORTANT COOLING TREND WILL BEGIN.
THE EXTENDED FORECAST PERIOD LOOKS TO START OUT MAINLY DRY BUT COLD
FOR MOST AREAS OF OUR FCST AREA...AS A LARGE UPPER LEVEL LOW DIGS
SOUTH OUT OF CANADA AND OVER THE MIDWEST THURSDAY INTO FRIDAY.
HOWEVER WITH COLD TEMPS AND FAVORABLE WIND DIRECTION...LAKE EFFECT
SNOW IS LIKELY FOR THE SNOWBELT REGION OF NWRN WI WED NIGHT THROUGH
FRIDAY. HOWEVER BY THE WEEKEND...A SFC HIGH WILL HAVE MOVED OVER
THE UPPER MIDWEST...RESULTING IN MODIFIED TEMPS AND A
WEST/SOUTHWESTERLY WIND FLOW AT THE SFC...WHICH SHOULD END THE LAKE
EFFECT SNOW ACROSS THE OUR WI ZONES.
AVIATION...11/29/18Z ISSUANCE...
A LOW CLOUD DECK WITH IFR/MVFR CIGS WILL LINGER OVER THE
NORTHLAND THROUGH EARLY THIS EVENING. HOWEVER THERE WILL BE AREAS
WHERE THE LOW CLOUDS SCATTER OUT...ESPECIALLY ACROSS NWRN WI AND
DOWNSLOPE OF THE SAWTOOTH RANGE. THE LOW COULD DECK SHOULD SCATTER
OUT EVERYWHERE AROUND 03Z MONDAY...EXCEPT ACROSS NWRN WI WHERE THE
LOW CLOUDS COULD PERSIST UNTIL 06Z TO 10Z. BECAUSE THE CLOUDS ARE
EXPECTED TO SCATTER OUT...THERE MAY BE ENOUGH RADIATIONAL COOLING
TO RESULT IN PATCHY FOG WITH MVFR/IFR VSBYS LATE TONIGHT AND EARLY
MONDAY MORNING. A QUICK MOVING CLIPPER SYSTEM FROM CANADA WILL
BRING INCREASING MID-LEVEL CLOUDS TO OUR FCST AREA LATE
TONIGHT...WITH LOW CLOUDS EXPECTED TO INCREASE ACROSS THE AREA ON
MONDAY. SNOW SHOWERS WITH REDUCED VSBYS ARE POSSIBLE ACROSS OUR
NWRN ZONES MONDAY MORNING AS WELL...WHICH WILL SPREAD SOUTHEAST IN
THE AFTERNOON.
&&
.POINT TEMPS/POPS...
DLH 22 35 27 38 / 10 50 10 10
INL 21 33 22 33 / 10 50 10 20
BRD 24 37 26 43 / 10 20 10 10
HYR 21 35 21 42 / 10 40 10 10
ASX 25 35 24 41 / 10 50 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
MELDE
