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000
FXUS63 KDLH 081022
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
422 AM CST SUN DEC 8 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 421 CST SUN DEC 8 2013

CENTER OF ARCTIC HIGH PRESSURE RIDGE HAS SHIFTED TO CENTRAL
WISCONSIN EARLY THIS MORNING. WINDS ARE STRONGEST ACROSS NORTHEAST
MINNESOTA WHERE WSW GRADIENT IN RETURN FLOW IS STARTING TO TIGHTEN
UP..BUT OVERALL WINDS ARE QUITE LIGHT. HOWEVER..WITH AIR TEMPS
FROM -25 TO -35..VERY LITTLE WIND IS REQUIRED FOR WIND CHILLS NEAR
-40F. GOING WIND CHILL ADVISORY WILL CONTINUE THRU LATE
MORNING..AT WHICH TIME RAPIDLY THICKENING CLOUD COVER AND WARM
ADVECTION SHOULD RESULT IN CESSATION OF WIND CHILLS COLDER THAN
-25F.

APPROACHING UPSTREAM IMPULSE IS ALREADY SPREADING LIGHT SNOW INTO
CENTRAL/SOUTHERN MINNESOTA..AND LIGHT SNOW SHOULD SPREAD INTO THE
SOUTHERN SECTIONS OF THE DULUTH CWA BY AROUND 6 AM..AND THEN
RAPIDLY NORTHEASTWARD FROM THERE THRU THE REMAINDER OF THE MORNING
AND MIDDAY HOURS. WHILE A 12-15 HOUR PERIOD OF LIGHT SNOW IS
EXPECTED OVER THE EASTERN HALF TO TWO-THIRDS OF THE CWA..RATES
WILL LIKELY BE RATHER ANEMIC..AND SHOULD GENERALLY LIMIT OVERALL
AMOUNTS. LATEST MODEL GUIDANCE CONTINUES TO BE QUITE CONSISTENT
WITH THIS MESSAGE WITH RATHER WEAK QPF..AND ONLY MODEST VERTICAL
MOTION FIELDS OWING TO STABILITY. IN ADDITION..MODEL FORECAST
SOUNDINGS INDICATE A QUASI-ISOTHERMAL LAYER FROM 925-600 MB IN THE
-18C TO -22C RANGE ALONG THE I35 CORRIDOR AND POINTS EAST..WHICH
IS ACTUALLY TOO COLD FOR DENDRITIC CRYSTAL GROWTH AND INTO THE
PLATES/SOLID COLUMNS REGIME..AND THIS IDEA SEEMS TO BE SUPPORTED
BY UPSTREAM DUAL-POL RADAR OBSERVATIONS. OVERALL..THIS SHOULD ACT
TO LIMIT ACCUMULATIONS. SOME LAKE ENHANCEMENT ALONG THE NORTH
SHORE WITH SOUTHERLY WINDS COULD LEAD TO SOME LOCALLY HEAVIER
AMOUNTS..AND SIMPLE LONG DURATION OF THE EVENT OVER PORTIONS OF NW
WI COULD ALSO LEAD TO A FEW LOCAL AMOUNTS GREATER THAN 5 INCHES
THERE. IN GENERAL..ENSEMBLE MEANS FROM THE SREF FOR ALL SITES
ALONG/EAST OF THE I35/NORTH SHORE RIBBON ARE CLUSTERED BETWEEN 3
AND 5 INCHES..WITH A SPREAD FROM ROUGHLY 2 TO 7 INCHES. THE
ADVISORY WE INHERITED FROM THE DAYSHIFT LOOKS IN GOOD SHAPE WITH
ONLY A FEW MINOR ADJUSTMENTS..INCLUDING A SLIGHT WESTWARD
EXPANSION OF THE ADVISORY AREA TO INCLUDE ALL OF NW WISCONSIN THRU
12Z MONDAY MORNING.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 421 CST SUN DEC 8 2013

THE NORTHLAND WILL REMAIN IN NORTHWEST FLOW ALOFT THROUGH MOST OF
THE PERIOD...WITH IT BECOMING A BIT MORE WESTERLY LATE. SEVERAL
SHORTWAVES WILL MOVE THROUGH AND BRING PERIODIC CHANCES FOR LIGHT
SNOW...WITH PRESENT INDICATIONS OF MOSTLY LIGHT ACCUMULATIONS WITH
EACH DISTURBANCE. THE MODELS ARE IN DECENT AGREEMENT THROUGH MID
WEEK...THEN THEY START TO DIVERGE...SO CONFIDENCE BEYOND WEDNESDAY
IS LOWER THAN AVERAGE.

ONE WAVE WILL BE MOVING THROUGH MONDAY NIGHT INTO TUESDAY MORNING
WITH DECENT FORCING ASSOCIATED WITH IT. IT IS MOVING QUICKLY...AND
WE BUMPED UP POPS FURTHER. MODELS STILL APPEAR TO BE UNDERDOING
THEIR QPF AND WE EXPECT A GENERAL 1-2 INCH SNOWFALL.

HIGH PRESSURE MOVING IN MID-WEEK WILL PROVIDE DRY CONDITIONS FOR
MOST AREAS UNTIL LATE IN THE WORK WEEK WHEN SEVERAL WAVES WILL BRING
CHANCES FOR LIGHT SNOW.

THE THREAT FOR SIGNIFICANT SNOWFALL FROM LAKE PROCESSES DOES NOT
LOOK VERY HIGH AT THIS POINT THROUGH THE PERIOD DUE TO MAINLY
WESTERLY FLOW. THERE MAY BE A PERIOD OR TWO WHERE A PASSING
SHORTWAVE MODULATES THE FLOW ENOUGH TO FOCUS A BRIEF PERIOD OF
MODERATE SNOW...BUT IT IS TOO DIFFICULT TO PINPOINT THAT AT THIS
TIME.

IT WILL REMAIN COLD THROUGH THE PERIOD...ESPECIALLY INTO THURSDAY.
THERE WILL LIKELY BE A NEED FOR ADDITIONAL WIND CHILL HEADLINES AT
TIMES. THE ECMWF/GFS DO SHOW A WARMUP JUST BEYOND THE EXTENDED
PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1145 PM CST SAT DEC 7 2013

A VERY COLD AND DRY AIR MASS WILL ALLOW VFR CONDITIONS TO PERSIST
ACROSS THE REGION THROUGH THE NIGHT. FOCUS TURNS TO LOW CLOUDS
AND SNOW SHOWERS THAN WILL NORTH OVER THE REGION THROUGH THE
AFTERNOON. EXPECTING MVFR CIGS AND FLURRIES TO REACH KBRD/KHYR
AROUND 14Z-16Z...FOLLOWED BY PREVAILING LIGHT SNOW AND PERIODS OF
IFR AFTER 18Z. THE LOW CLOUDS WILL REACH THE KHIB/KINL AREAS LATER
IN THE AFTERNOON...MAINLY AFTER 20Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH   9  -1   4  -9 /  90  90  10  40
INL   6  -5  -3 -15 /  60  60  20  50
BRD   8  -4  -1  -6 /  80  80  10  40
HYR  11   3   3 -12 / 100 100  10  40
ASX  12   7   8  -3 / 100 100  30  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 11 AM CST THIS MORNING FOR MNZ010>012-
     018>021-025-026-033>038.

     WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST MONDAY FOR
     MNZ020-021.

WI...WIND CHILL ADVISORY UNTIL 11 AM CST THIS MORNING FOR WIZ001>004-
     006>009.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ001>004-
     006>009.

LS...NONE.
&&

$$

SHORT TERM...MILLER
LONG TERM...MELDE
AVIATION...MELDE