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000
FXUS63 KDLH 111025
AFDDLH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
425 AM CST WED DEC 11 2013

.SYNOPSIS...
ISSUED AT 423 AM CST WED DEC 11 2013

REGION REMAINS UNDERNEATH THE INFLUENCE OF ANOMALOUS HUDSON BAY
VORTEX WITH LARGE SFC HIGH BUILDING IN FROM THE WEST. NW BDRY LYR
FLOW IS KEEPING LAKE CLOUDS ACROSS SOUTH SHORE EAST OF KSUW. LATEST
RAP13 INDICATES 85/70H LAYER HUMIDITY CONTINUES TO LOWER AS
SUBSIDENCE ON SYNOPTIC SCALE INCREASES. ENOUGH FETCH IS OCCURRING
OVER LAKE SUPERIOR INTO BAYFIELD PENINSULA AND POINTS EAST TO KEEP
SNSH OCCURRING IN SOME LOCATIONS. SFC TEMPS NOT AS LOW AS PREVIOUS
NIGHTS AND WIND FAIRLY LIGHT SO WIND CHILL VALUES ARE REMAINING IN
THE 30 TO 35 BELOW RANGE IN MANY LOCATIONS...WITH A FEW AS LOW AS 37
BELOW IN PAST 3 HRS. A FEW LOWER VALUES ARE OCCURRING JUST WEST OF
CWA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 423 AM  CST WED DEC 11 2013

TODAY...LARGE SFC HIGH WILL MOVE SOUTH OF THE REGION TODAY. OTHER
THAN LAKE CLOUDS/SNSH CONTINUING OVER SOUTH SHORE/GOGEBIC
RANGE...THE PATTERN WILL REMAIN VERY COLD AND DRY. MAX TEMPS LOWER
THAN YESTERDAY AS 925/850 THERMAL TROUGH ADVECTS ACROSS THE CWA.
MAIN CHANGE FROM PREVIOUS FCST WAS TO DROP WIND CHILL WARNING AFTER
16Z. DESPITE VERY COLD TEMPS TODAY THE LATEST FCST TEMP/WIND VALUES
IS NOT SUPPORTING PREVIOUS VALUES.

TONIGHT/TOMORROW...MDLS IN AGREEMENT THAT A MID LVL SHORTWAVE WILL
MOVE SOUTH OF THE REGION. AHEAD OF THE SYSTEM INCREASING LOW/MID LVL
FRONTOGENESIS WILL SPREAD ACROSS THE SWRN CWA LATE THIS EVENING.
INCREASED POPS BASED ON LATEST THERMAL LIFT AND WOULD SUSPECT THAT
EVEN HIGHER POPS MAY BE NEEDED IN NEXT FCST UPDATE. LET FLURRIES
LINGER OVER SRN/SERN CWA THRU 18Z TOMORROW DUE TO PRESENCE OF UPPER
JET AXIS OVERHEAD AND RESIDUAL MID LVL FRONTOGENESIS. TEMPS TONIGHT
WILL EXHIBIT A NON DIURNAL TREND AS THE APPROACHING WAA REGIME AND
CLOUDS/PRECIP ALLOW TEMPS TO STEADY AND EVEN RISE IN MANY LOCATIONS
AFTER MID TO LATE EVENING. THIS WILL ALSO RAISE SOME DOUBT AS TO THE
VALIDITY OF THE EXISTING WIND CHILL ADVISORY. WILL LET NEXT SHIFT
DECIDE IF THE ADVISORY CAN BE LOWERED OR CONFINED TO ARROWHEAD.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 423 AM CST WED DEC 11 2013

BELOW NORMAL TEMPERATURES AND AN UNSTABLE NW FLOW WILL PERSIST
THROUGH THE EXTENDED. MODELS ARE IN GOOD AGREEMENT THAT A DIGGING
SHORT WAVE TRANSLATES ACROSS THE WRN LAKE SUPERIOR REGION
SATURDAY...BRINGING CHC FOR LIGHT SNOW. HAVE INCREASED POPS DURING
THIS TIME WITH THE BEST CHC FOR A FEW INCHES OF NEW SNOW ALONG THE
NORTH SHORE OF LAKE SUPERIOR AS SRLY BOUNDARY LAYER WINDS DEVELOP
AHEAD OF THE SFC REFLECTION LOW. ANOTHER SHOT OF ARCTIC AIR WILL
FOLLOW THE VORT SAT NIGHT/SUNDAY WITH H85 TEMPS RETURNING TO THE
NEGATIVE 20S C. A CLIPPER WILL DROP OVER THE REGION DURING THE
MONDAY/TUESDAY TIME FRAME BRINGING A CHC FOR SNOW ALONG WITH A BRIEF
SLIGHT-WARM UP. HOWEVER...LONG RANGE MODELS ARE SUGGESTING A VERY
LARGE ARCTIC AIR MASS SETTLES OVER SRN CANADA BY NEXT
WEEK...THREATENING TO SINK OVER THE NORTHLAND THROUGH THE CHRISTMAS
HOLIDAY.



&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM CST TUE DEC 10 2013

VFR CONDITIONS ARE EXPECTED ACROSS THE NORTHLAND THROUGHOUT THE
TAF PERIOD. DUE TO THE VERY COLD AIR...VERY LOCALIZED AND BRIEF
REDUCTIONS IN VSBY/CIGS TO MVFR AND IFR WILL BE POSSIBLE AT TIMES.
BUT FOR THE MOST PART IT SHOULD BE VFR.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  -3 -11  10  -3 /   0  20  10  30
INL  -6 -21   7 -18 /   0  10  10  20
BRD  -3 -12  15  -3 /   0  40  10  20
HYR  -3 -14  13  -1 /   0  40  20  30
ASX  -1  -7  13   1 /  30  20  30  40

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL WARNING UNTIL 10 AM CST THIS MORNING FOR MNZ010>012-
     018>021-025-026-033>038.

     WIND CHILL ADVISORY FROM 10 AM THIS MORNING TO 6 AM CST THURSDAY
     FOR MNZ010>012-018>021-025-026-033>038.

WI...WIND CHILL WARNING UNTIL 10 AM CST THIS MORNING FOR WIZ001>004-
     006>009.

     WIND CHILL ADVISORY FROM 10 AM THIS MORNING TO 6 AM CST THURSDAY
     FOR WIZ001>004-006>009.

LS...SMALL CRAFT ADVISORY UNTIL 4 AM CST THURSDAY FOR LSZ121-140>148.

&&

$$

SYNOPSIS...CANNON
SHORT TERM...CANNON
LONG TERM...GRANING
AVIATION...DAP