Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 231633 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1033 AM CST MON FEB 23 2015

.UPDATE...
ISSUED AT 1033 AM CST MON FEB 23 2015
COLD ARCTIC HIGH PRESSURE IS CENTERED ALONG THE IA/MO BORDER AS OF
MID MORNING..WITH SURFACE PRESSURE GRADIENT RAPIDLY TIGHTENING
ACROSS THE DULUTH CWA AS NEXT UPSTREAM WAVE RAPDILY APPROACHES
FROM MANITOBA. ISALLOBARIC COMPONENT DRIVEN BY 6-8 MB/3 HOUR
PRESSURE FALLS ACCOMPANYING THIS SYSTEM WILL AID IN SW WINDS
STRENGTHENING SIGNFICANTLY BY MID AFTERNOON IN MOST AREAS..ALONG
WITH WELL-DEFINED AREA OF LIGHT SNOW CURRENTLY EVIDENT ON CANADIAN
RADARS MOVING INTO THE NW CWA AFTER 3 PM.

DESPITE INCREASING WINDS..LOW LEVEL WARM ADVECTION WILL BE VERY
STRONG THE NEXT 6-12 HOURS..RESULTING IN SIGNIFICANT WARMING INTO
THE SINGLE DIGITS/TEENS ABOVE ZERO IN MOST AREAS. THUS..WIND
CHILLS ARE EXPECTED TO RISE RAPIDLY ABOVE ANY HIGHLIGHT THRESHOLDS
IN THE NEXT HOUR..AND THE WIND CHILL WARNING/ADVISORY WAS ALLOWED
TO EXPIRE AS SCHEDULED AT 10 AM.

OVERALL FORECAST IS IN PRETTY GOOD SHAPE..WITH THE ONLY MINOR
ADJUSTMENTS TO TIMING ON THE LIGHT SNOW THIS AFTERNOON AND ALSO TO
ADJUST POPS UP A BIT. WE ALSO ADJUSTED SNOW AMOUNTS UPWARD JUST A
TAD FOR TONIGHT. RAPID MOVEMENT OF THE SYSTEM WILL MAKE THE PERIOD
OF ACCUMULATING SNOW ONLY A FEW HOURS LONG AT ANY ONE
LOCATION..BUT WITH FAIRLY HIGH SNOW RATIOS A FEW AREAS COULD
RECEIVE OVER 2 INCHES ESPECIALLY TO THE NORTH/EAST OF THE TWIN
PORTS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 320 AM CST MON FEB 23 2015

AT 315 PM...A LARGE AREA OF SURFACE HIGH PRESSURE WAS CENTERED
OVER CENTRAL IOWA. THERE WAS A LARGE SURFACE LOW PRESSURE SYSTEM
IN NORTHERN CANADA. THE NORTHLAND HAD CLEAR SKIES AND LIGHT WEST
TO SOUTHWEST WINDS. TEMPERATURES HAD PLUMMETED TO ABOUT -15 TO -30
DEGREES OVER THE FORECAST AREA...WITH THE COLDEST TEMPERATURES
OVER FAR NORTHERN MINNESOTA. THERE WERE WIDESPREAD WIND CHILLS OF
-25 TO -40 DEGREES WHEREVER LIGHT WINDS WERE REPORTED.

THIS MORNING...SOUTHWEST WINDS WILL DEVELOP AND INCREASE LATER
THIS MORNING IN RESPONSE TO THE APPROACHING LARGE LOW PRESSURE
SYSTEM IN NORTHERN CANADA. DESPITE THE INCREASING WIND
SPEEDS...WIND CHILL CONDITIONS WILL QUICKLY IMPROVE IN THE HOURS
AFTER SUNRISE. THE AIR TEMPERATURE WILL QUICKLY RISE BECAUSE OF
THE SUNNY SKIES AND SW FLOW. THE WIND CHILL WARNINGS AND
ADVISORIES ARE SET TO EXPIRE AT 10 AM...AND THAT STILL LOOKS LIKE
A GOOD ENDING TIME.

THIS AFTERNOON...STRONG AND GUSTY SW FLOW WILL DEVELOP AS THAT
LOW CONTINUES TO MOVE SOUTH FROM NORTHERN CANADA TO THE SW SIDE OF
HUDSON BAY. THE NAM12/GFS/RAP13 MODEL SOUNDINGS INDICATE THE
LIKELIHOOD OF WIDESPREAD WIND GUSTS OF 25 TO 35 MPH DURING THE
MIDDLE AFTERNOON THROUGH EARLY EVENING. THERE IS THE POTENTIAL FOR
STRAY WIND GUSTS OF MORE THAN 35 MPH. THERE WILL BE INCREASING
CLOUD COVER FROM THE NORTH WITH THE APPROACHING SYSTEM AND
POTENT SHORTWAVE. HIGH TEMPERATURES SHOULD CLIMB TO THE LOW TEENS
TO NEAR 20 DEGREES. THE WARMER CONDITIONS WILL OVER THE WESTERN
FORECAST AREA.

LATE THIS AFTERNOON AND TONIGHT...THE LOW WILL MOVE FROM FAR
NORTHWESTERN ONTARIO TO FAR NORTHEASTERN ONTARIO OVERNIGHT. A
POTENT SHORTWAVE WILL DIVE FROM MANITOBA AND ONTARIO SOUTH THROUGH
THE NORTHLAND. THE SHORTWAVE WILL LATER BE FOLLOWED BY A STRONG
ARCTIC COLD FRONT THAT WILL MOVE THROUGH THE NORTHLAND LATE
TONIGHT. THE SHORTWAVE AND COLD FRONT WILL LIKELY SPREAD LIGHT
SNOW THROUGH THE NORTHLAND...FROM NORTH TO SOUTH...LATE THIS
AFTERNOON THROUGH TONIGHT. THE COMBINATION OF THE GUSTY WIND AND
LIGHT SNOW COULD RESULT IN PATCHY BLOWING SNOW AND REDUCED
SIGNIFICANTLY VISIBILITY...ESPECIALLY IN MORE OPEN COUNTRY. SOME
AREAS COULD GET UP TO AROUND 1 INCH OF SNOWFALL.

TUESDAY...THE LOW...WHICH WILL BE OVER FAR NE ONTARIO BY SUNRISE
TUESDAY...WILL THEN MOVE TO THE FAR SOUTHERN TIP OF JAMES BAY BY
THE END OF THE AFTERNOON. ITS COLD FRONT WILL FINISH MOVING SOUTH
THROUGH THE NORTHLAND DURING THE MORNING. THERE COULD BE LINGERING
LIGHT SNOW...ESPECIALLY IN THE MORNING AND OVER NW WISCONSIN AND
THE ARROWHEAD. MODEL SOUNDINGS INDICATE THERE COULD BE DEEP MIXING
WHICH COULD DRAW DOWN STRONG WINDS. WIDESPREAD NW WINDS OF 15 TO
25 MPH WITH GUSTS AS HIGH AS 35 MPH WILL DEVELOP BY THE LATE
MORNING. THE SKIES SHOULD GRADUALLY CLEAR THROUGH THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM CST MON FEB 23 2015

A ZONAL FLOW...COMBINED WITH BUILDING SFC HIGH PRESSURE OVER THE
UPPER PLAINS...WILL BRING BELOW NORMAL TEMPERATURES AND OVERALL
DRY CONDITIONS THROUGH THE WORK WEEK. A FEW FAST MOVING SHORT
WAVES EMBEDDED IN THE NW FLOW WILL BRING PERIODS OF CLOUDS AND
FLURRIES...BUT NO ACCUM IS EXPECTED AT THIS TIME. A RETURN FLOW
WILL DEVELOP AND BRING A BRIEF WARMING TREND FOR THE WEEKEND.

FOCUS TURNS TO A NEGATIVELY TILTED LONG WAVE TROUGH THAT MOVES
INTO THE WESTERN CONUS/ROCKIES THROUGH THE WEEKEND. THE LATEST
ECM/GFS ARE SUGGESTING THAT THE UPPER STREAM TROUGH MOVES INTO THE
ONTARIO/MINNESOTA REGION SUNDAY...ALLOWING FOR A STRONG THERMAL
GRADIENT TO DEVELOP IN THE CONFLUENT FLOW OVER THE CENTRAL
CONUS/OHIO RIVER VALLEY. MODELS ARE ALSO IN AGREEMENT THAT A SHORT
WAVE ROUNDS THE BASE OF THE TROUGH...TRANSLATING ALONG THE THERMAL
BOUNDARY INTO THE CENTRAL PLAINS AND EVENTUALLY GREAT LAKES REGION
EARLY NEXT WEEK. A CORRIDOR OF SNOW...POTENTIALLY HEAVY...WILL BE
FOUND ON THE NORTHERN FLANK OF THE THERMAL GRADIENT/FRONTOGENESIS.
AT THIS TIME LONG RANGE MODELS ARE SHOWING THE MOISTURE/SNOW
REACHES AS FAR NORTH AS SOUTHERN MN AND WIS. HOWEVER...THIS SYSTEM
IS VERY FAR OUT IN THE LONG RANGE SO TIMING AND TRACK ARE OPEN TO
QUITE A BIT OF UNCERTAINTY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 602 AM CST MON FEB 23 2015

VFR CONDITIONS WILL PREVAIL THROUGH THE DAY. SOUTHWEST WINDS WILL
STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT TODAY. EXPECT GUSTS TO
DEVELOP AROUND 16Z..WITH FREQUENT GUSTS AROUND 30KT THROUGH THE
AFTERNOON AND INTO THE EARLY EVENING. CEILINGS WILL LOWER TO MVFR
WITH LIGHT SNOW SHOWERS WITH THE FRONTAL PASSAGE OVERNIGHT. WINDS
WILL SUBSIDE BRIEFLY AS THE FRONT PASSES...THEN INCREASING OUT OF
THE NORTHWEST LATE IN THE NIGHT.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  13  12  19 -12 /  10  70  30   0
INL  18  11  12 -21 /  50  80  30   0
BRD  18  17  21  -9 /  10  40  20   0
HYR  12  10  23 -11 /   0  60  40  10
ASX  13  12  22  -7 /  10  70  40  10

&&

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

$$



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