FXUS63 KDLH 050843
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
243 AM CST SUN FEB 5 2012

.SHORT TERM...

TODAY THROUGH MONDAY AFTERNOON...

MORNING LOW CLOUDS AND PATCHY FOG AGAIN TODAY...AND ABOVE AVERAGE
TEMPERATURES THROUGH MONDAY WILL BE THE MAIN FOCUS OF ATTENTION
DURING THE SHORT TERM.

A BLOCKING PATTERN REMAINS IN PLACE ACROSS MUCH OF THE WRN U.S.
AS AN UPPER LEVEL HIGH PRESSURE OVER THE NRN ROCKIES CONTINUES TO
SIT JUST NORTH OF A WEAKENING UPPER LOW...GETTING THE SQUEEZE-PLAY
AS IT TRIES TO MOVE EWD THROUGH THE MID MS VALLEY...BETWEEN A NRLY
S/W DROPPING SOUTH FROM THE GREAT LAKES AND A STRONG SUB-TROPICAL
JET STREAMING NEWD FROM MEXICO. AT THE SURFACE...MUCH OF THE MID
SECTION OF THE COUNTRY IS BEING DOMINATED BY AN AREA OF HIGH
PRESSURE...WITH A COUPLE SFC TROUGHS MOVING INTO THE EAST
COAST...AND ANOTHER JUST OFF THE PAC NW COAST.

THIS PATTERN WILL ALLOW THE VERY MILD WEATHER CONDITIONS TO
PERSIST THROUGH TOMORROW FOR ALL OF THE NORTHLAND. THE UPPER RIDGE
WILL HAVE CONSIDERABLY WARM AIR ASSOCIATED WITH IT. 925MB TEMPS
ARE FORECAST TO BE +4 TO +6 DEG C TODAY...AND WITH MIXING HEIGHTS
AROUND 1K FT THIS AFTERNOON...SHOULD HAVE NO PROBLEMS MIXING DOWN
THIS AIR AND WARMING INTO THE UPPER 30S AND LOWER 40S TODAY. THE
RECORD HIGH IN DULUTH TODAY IS 45. WE COULD APPROACH THAT RECORD
THIS AFTERNOON...BUT THINK THE LIMITED AMT OF SUN IN THE MORNING
COMBINED WITH THE STILL RELATIVE LOW SUN ANGLE EVEN WITH MOSTLY
SUNNY SKIES IN THE AFTERNOON...SHOULD REMAIN SAFE WITH THAT 2005
RECORD.

ATTM...MUCH OF NE MN IS COVERED IN LOW CLOUDS AND PATCHY FOG.
MOST OF NW WI IS STILL SEEING CLEAR SKIES. EXPECTING MOST OF THE
CLEAR AREAS...EXCEPT AROUND THE PERIPHERY OF THE LAKE TO FILL IN
BY 12Z THIS MORNING. THE WARMER AIR ALOFT ADVECTING IN FROM THE NW
ASSOCIATED WITH THE UPPER RIDGE IS ALLOWING A FAIRLY STRONG LOW
LEVEL INVERSION TO FORM...WHICH IS AIDING IN THE DEVELOPMENT AND
SUSTAINABILITY OF THIS CLOUD SHIELD AND THE PATCHY FOG. WILL
LIKELY SEE A FEW VSBYS DOWN TO 1/2MI OR LESS AT TIMES THIS
MORNING. ALTHOUGH WIDESPREAD/LONG-LASTING DENSE FOG IS NOT
ANTICIPATED...SO NO ADVISORIES ARE EXPECTED EITHER. SHOULD SEE THE
FOG LIFT BY 15Z AND CLOUDS BURN OFF BY 17/18Z.

A COLD UPPER TROUGH WILL BEGIN TO DROP SOUTH OUT OF NRN CANADA
MONDAY AND BEGIN TO USHER IN ADDITIONAL CLOUD COVER AND PRODUCE A
FEW FLURRIES ACROSS THE NRN COUNTIES BY LATE MON
AFTERNOON/EVENING. TEMPERATURES WILL ONLY REACH INTO THE UPPER 20S
ACROSS THE NORTH MONDAY UNDER MORE CLOUDS...WHILE AREAS TO THE
SOUTH WITH MORE SUN WILL WARM INTO THE UPPER 30S/LOWER 40S.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY...

A VERY DRY POLAR FRONT MOVES STRAIGHT SOUTH THROUGH THE AREA EARLY
MONDAY EVENING...LOW LEVEL EQUIVALENT POTENTIAL TEMPERATURE
PACKING IMPLIES THE EFFECTIVE AIR MASS CHANGE REACHING DULUTH MID-
EVENING AND GOING THROUGH MILLE LACS LAKE AND BEYOND THE SAND
HILLS ABOUT MIDNIGHT MONDAY NIGHT. BEHIND THE FRONT...LOW LEVEL
WINDS ARE ONSHORE WITH LITTLE IF ANY DIRECTIONAL SHEAR ACROSS THE
COASTAL COUNTIES OF NORTHWEST WISCONSIN AND PLENTY OF TEMPERATURE
DIFFERENCE BETWEEN THE RAPIDLY COOLING COLUMN AND THE OPEN LAKE.
THIS ARGUES FOR SUBSTANTIAL LAKE-EFFECT SHOWERS FORMING AND MOVING
ONSHORE EXCEPT THE INCOMING AIR MASS IS EXTREMELY DRY...SO WE
LIMITED OUR FORECAST FOR THOSE COUNTIES TO HIGH-END SCATTERED ALL
THE WAY WEST TO THE SUPERIOR AREA MONDAY NIGHT AND EARLY TUESDAY.
AS THE POLAR HIGH MOVES SOUTH THROUGH THE DAKOTAS AND THE SURFACE
RIDGE CROSSES THE SOUTHERN LAKE SHORE...WINDS RAPIDLY BACK AND
DECREASE...MOVING SHOWERS OFFSHORE TUESDAY AFTERNOON. THIS 18 HOUR
WINDOW FOR LAKE-EFFECT SHOWERS BARELY GIVES THEM ENOUGH TIME TO
FORM AND GET ESTABLISHED...THAT IS WHY WE HAVE NOT YET GONE WITH
LIKELY WORDING.

THE NEXT EVENT IS THE PASSAGE OF AN ARCTIC FRONT...ONLY THE
SECOND SO FAR THIS WINTER...THURSDAY NIGHT. THE MODELS SEEM TO BE
GOING BACK AND FORTH ON THIS...WITH THE LATEST GFS BEING QUITE
AGGRESSIVE WITH THE COOLING...WITH ITS UPPER RIDGING OVER DAVIS
STRAIGHT. THE EUROPEAN IS NOT AS STRONG WITH THAT DAVIS STRAIGHT
RIDGING...SO IT TENDS TO KEEP THE COLDEST AIR JUST TO OUR NORTH
AND EAST. EARLIER EUROPEAN RUNS FLIP-FLOPPED ON THE DAVIS STRAIGHT
SITUATION...WITH EXTREMELY HARSH COOLING...AS COLD AS -35C AT 850
MB OVER US FRIDAY AND SATURDAY. ALL THE MODELS CONTINUE TO BE
SURPRISINGLY DRY WITH THE ARCTIC FRONT PASSAGE...BUT THE MOST
RECENT GFS DOES BRING THE CORE OF THE COLD AIR DIRECTLY SOUTHWARD
TOWARD US RATHER THAN BACK DOORING IT INTO OUR AREA FROM THE
NORTHEAST...ALLOWING A LOW TO RAPIDLY DEVELOP OVER LAKE SUPERIOR
AND SUGGESTING A BRIEF SHOT OF SNOW SHOWERS WHICH MIGHT GIVE ABOUT
AN INCH OF SNOW TO MANY AREAS. WE LEAVE OPEN THE POSSIBILITY OF
LAKE-EFFECT SHOWERS BUT WE NEED TO SEE IF LOW LEVEL WINDS WILL BE
BRIEFLY ONSHORE AS THE EUROPEAN HINTS AT OR WILL REMAIN OUT OF THE
WEST. THE EUROPEAN TRIES TO WARM US UP...AGAIN WITH LITTLE IF ANY
MOISTURE DURING THE COMING WEEKEND WHILE THE GFS WAITS UNTIL
SUNDAY NIGHT.

&&

.AVIATION...06Z TAFS...
IFR CIGS WILL OVERSPREAD THE AREA AS CLOUDS MOVE IN FROM THE W AND
FROM THE E. SOME QUESTION ON BR/FG POTENTIAL...BUT MODELS INSIST
ON FORMATION AT ALL LOCATIONS AND HAVE A MENTION UNTIL 15Z. AFTER
15Z...VFR WITH LOW CLOUDS AND BR QUICKLY ERODING.

&&

.POINT TEMPS/POPS...
DLH 39 22 34 8 / 0 0 10 10
INL 39 16 26 -2 / 0 0 10 0
BRD 40 22 35 9 / 0 0 0 10
HYR 41 24 39 13 / 0 0 10 20
ASX 42 25 38 13 / 0 0 10 40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...TENTINGER
LONG TERM....EOM
AVIATION...GSF


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