FXUS63 KDLH 052045
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
245 PM CST SAT DEC 5 2009
.DISCUSSION...
THRU TUE...
COL AREA CURRENTLY OVR CWA WITH LIGHT WINDS AND PSUN SKIES. SHARP
UPR LVL TROF ROTATING ARND ERN CN VORTEX GENERATING A FEW -SHSN
OR FLURRIES WHEREVER THERE IS SUFFICIENT CLD CVR. BAND OF HEAVIER
SN ALG W SIDE OF BAYFIELD PEN HAS BEEN WEAKENING OVR PAST FEW HRS
AND SHUD CONT DOING SO THRU THE EARLY EVE. SOME WEAK LES WILL CONT
ALG S SHORE THRU MON NITE AS LOLVL WINDS RETAIN A NLY COMPONENT.
TUE WILL SEE A COMMENCEMENT OF THE MAIN EVENT FOR THE WEEK AS MAJ
SFC LOW EMERGES FROM THE SRN ROCKIES AND BEGINS AN EWD TREK ACRS
SRN KS/NRN OK. MODELS IN RATHER GOOD AGMT THRU LATE TUE. FCST WILL
SHOW AN INCRS FROM SLGT TO HIGH CHC POPS DURING THE DAY ON TUE.
GLFMEX BEGINS TO OPEN UP ABT THAT TIME...BUT WITH A LOW TRACK ACRS
CENT MS VLY TWRD LWR MI...AXIS OF MAX SNOWFALL SHUD REMAIN S OF
OUR CWA.
TUE NITE THRU SAT...
NRN BRANCH OF POLAR WESTERLIES DOMINATES THE REGION THIS PERIOD.
ALTHOUGH MID LVL HEIGHTS WILL RISE SOMEWHAT BY THE END OF THE
WEEK...ANOMALOUS 85H TEMPS ARE EXPECTED THROUGHOUT THE WEEK. THE
RESULT IS A COLD WEEK WITH TEMPS BELOW NORMAL. MAIN BAROCLINIC
ZONE...OR STORM TRACK...REMAINS SUPPRESSED TO THE SOUTH OF CWA
ALONG A SRN PLAINS TO CORN BELT TO ERN GT LAKES PATH. THIS SHOULD
KEEP HEAVIEST SNOW AXIS FROM CYCLONE DEVELOPMENT SOUTH OF REGION.
STRONG AGREEMENT EXISTS BETWEEN EC/GFS ON EVOLUTION OF MAIN SFC
LOW TUES/WED. MAIN CHALLENGE WILL BE DETERMINING EXTENT OF
SNOWFALL ACROSS SERN HALF OF CWA FROM SYNOPTIC SYSTEM TO THE
SOUTH...AND QUANTIFICATION OF LAKE EFFECT SNOW AS BDRY LYR WINDS
SWING INTO MORE FAVORABLE TRAJECTORY TUES NIGHT/WED. SYNOPTIC
SCALE LIQUID QPF AT THIS POINT SUGGESTS ABOUT
.10" NEAR TWIN PORTS...CLOSER TO .25" OVER SERN CRNR OF CWA.
ALTHOUGH ITS TOO EARLY TO DETERMINE EXACT SNOW/LIQUID
RATIO...CLIMATOLOGICAL LSR OF APPROX 16:1 WOULD GIVE SEVERAL INCHES
OVER TWIN PORTS AND SOME 3 TO 5 INCHES POSSIBLE OVER SERN PART OF
CWA. AGAIN...UNTIL TRACK IS MORE CERTAIN AND LAKE EFFECT
CONSIDERATIONS ARE MORE SPECIFIC...WILL NEED TO WAIT BEFORE NAILING
DOWN MORE SPECIFIC SNOW ACCUMULATIONS.
&&
.AVIATION...18Z TAF ISSUANCE...
MAINLY VFR LATE THIS AFTERNOON AT HYR/DLH/BRD WHILE HIB AND INL HAVE
MVFR CLGS. CONFIDENCE NOT HIGH ON REDEVELOPMENT OF LOW CLOUD DECK
OVERNIGHT SO KEPT FCST CONSERVATIVE WITH REGARD TO CEILINGS
LOWERING. LATEST SREF PROBABILITY FCST OF MVFR CEILINGS DECREASES
THROUGH THE PERIOD AT MOST SITES EXCEPT PERHAPS INL/HIB EARLY
SUNDAY. WILL USE THIS AS A HEDGE AND BRINK CEILINGS DOWN AT BOTH
LOCATIONS.
&&
.POINT TEMPS/POPS...
DLH 10 20 9 19 / 10 10 10 10
INL 6 16 4 15 / 10 10 10 10
BRD 8 20 7 20 / 10 10 10 10
HYR 11 24 7 22 / 10 10 20 10
ASX 16 25 13 24 / 30 30 30 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
04/CANNON
