FXUS63 KDLH 031533 AAB
AFDDLH
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
933 AM CST THU DEC 3 2009
.UPDATE...ADDED ISOLATED/SCATTERED SNOW SHOWERS ACROSS THE CWA.
ACCUMULATION WILL BE VERY LIGHT...A COUPLE OF TENTHS OR SO. WEAK
VORT PUSHING SOUTH THROUGH THE IRON RANGE IS SQUEAKING OUT THE
LITTLE MOISTURE IN THE STRATUS. MANY AREAS WILL SEE FLURRIES WITH A
VERY SHALLOW MOIST LAYER.
WE WILL CONTINUE THE LAKE EFFECT SNOW ADVISORY FOR THIS UPDATE.
HIGHEST SNOW TOTALS REPORTED WERE 2.0 AT UPSON OVERNIGHT IN IRON
COUNTY AND 3.2 NEAR CLAM LAKE...NEAR THE BAYFIELD/ASHLAND COUNTY
BORDER. WINDS ARE SHIFTING AROUND TO THE NNW...WHICH WILL NOW
FAVOR IRON COUNTY. LATEST SATELLITE OBSERVATIONS INDICATE THAT
SLIGHTLY DEEPER SATURATION (850-700) IS FILLING IN OVER WESTERN
LAKE SUPERIOR...THOUGH IT WILL STILL REMAIN BORDERLINE. LIGHT SNOW
HAS NOW BEGUN TO FALL AT PHILLIPS IN PRICE COUNTY AND NEIGHBORING
VILAS COUNTY.
SO FAR...THE CLOUD LAYER HAS BEEN A BIT SHALLOW TO PRODUCE MORE
THAN THE 1-3 INCHES SEEN SO FAR. SFC-850 DELTA T'S REMAIN MODERATE
WITH SHIP OBS REPORTING 6-7C SFC TEMP...AND 850 TEMPS 10C OR SO.
HAVE LOWERED AMOUNTS A BIT...STILL LOOKING AT AN ADDITIONAL 1-3
INCHES...CAN STILL POSSIBLY BRING SOME 4-5 INCH TOTALS...THOUGH
CONFIDENCE IS CERTAINLY LOWER AT THIS POINT. /DONOFRIO
&&
.PREV DISCUSSION... /ISSUED 532 AM CST THU DEC 3 2009/
AVIATION...12/3 12Z TAFS
MVFR CEILINGS...WITH A FEW POCKETS OF IFR...WILL CONTINUE THROUGH
MOST OF THE PERIOD. AN UPPER LEVEL AREA OF LOW PRESSURE WILL
CONTINUE TO DOMINATE THE WEATHER...ALONG WITH PLENTY OF LOW LEVEL
MOISTURE. THE MVFR CEILINGS...ALONG WITH AREAS OF FLURRIES OR
LIGHT SNOW WILL CONTINUE. A FEW OF THE SNOW SHOWERS WILL REDUCE
VSBYS TO 2-3SM. AREAS ALONG THE SOUTH SHORE OF LAKE SUPERIOR WILL
SEE HEAVIER SNOW SHOWERS...ESPECIALLY EAST OF KASX TOWARD KIWD. /MELDE
PREV DISCUSSION... /ISSUED 330 AM CST THU DEC 3 2009/
DISCUSSION...
LES ALONG SOUTH SHORE HAS GRADUALLY SHIFTED EWRD FROM
DOUGLAS/BAYFIELD COUNTIES INTO ASHLAND COUNTY EARLY THIS MORNING AS
WINDS BACK. EXPECT THIS TREND TO CONTINUE THIS MORNING. WL CONTINUE
LES ADVISORY FOR MORE ACCUMULATING SNOW IN ASHLAND AND IRON
COUNTIES. REPORTS SLIM ATTM...BUT EARLIER REPORT OF HALF INCH AT
GILE. WEB CAM AT HURLEY APPEARS TO BE AN INCH OR SO OF NEW SNOW.
ASX AWOS REPORT LIGHT SNOW WITH VSBY AS LOW AS 3/4SM. WITH A GOOD FETCH...
ABOUT A -10 TO -12 DEGREE DELTA T BETWEEN LAKE AND 850 MB
INCREASING SHEAR AND RISING INVERSION HGTS...LES WILL GET
ORGANIZED THIS MORNING AND CONTINUE THROUGH THE DAY. WILL STAY
WITH THE 4-7" AMOUNTS.
ELSEWHERE- LITTLE CHANGE IN THE PATTERN WITH UPPER LOW/CYCLONIC
FLOW OVR THE REGION BRINGING WAVES THROUGH. TIMING DIFFICULT AND
LIKE THE BROADBRUSH SNOWSHOWER TECHNIQUE THROUGH FRIDAY.
IN PAST 2 HOURS MORE ECHOES SHOWING UP ON RADAR FROM IRON RANGE AND
SOUTH...IN RESPONSE TO NEXT WAVE COMING SOUTH OUT OF CANADA.
NO CHANGE TO TEMPS...MORE SEASONABLE WITH DAYTIME HIGHS IN
20S...LOWS IN THE TEENS. /CLC
EXTENDED...FRIDAY NIGHT THROUGH WEDNESDAY
MODELS ARE IN OK AGREEMENT EARLY...THEN DIVERGE SIGNIFICANTLY BEYOND
THE FIRST 24 HOURS OF THE EXTENDED PERIOD. THE DIFFERENCES ARISE IN
HOW THE GFS/ECMWF HANDLE THE SHORTWAVE/UPPER LOW THAT DROPS SOUTH TO
SOUTHWEST THROUGH ONTARIO. THE ECMWF WEAKENS THIS FEATURE...AND
MOVES IT EAST ON SUNDAY...WHERE THE GFS DROPS IT FURTHER WEST AND
KEEPS THE CLOSED LOW OVER THE DAKOTAS. WE DID NOT MAKE TOO MANY
CHANGES TO THE EXTENDED...BUT DID ADJUST/ADD SOME POPS FROM FRIDAY
NIGHT THROUGH SUNDAY. WE ADDED SOME POPS TO THE NORTH SHORE...DOWN
INTO THE TWIN PORTS ON SATURDAY WITH BOTH MODELS SHOWING WEAK
ONSHORE WINDS IN THESE AREAS. WE ALSO ADDED SOME POPS TO THE SOUTH
SHORE SATURDAY NIGHT INTO SUNDAY FOR SOME LES. OVERALL...WE LEANED
TOWARD THE ECMWF EARLY IN THE PERIOD. THE GFS ENSEMBLE MEAN WAS DID
NOT SHOW REAL GOOD AGREEMENT WITH THE OPERATIONAL RUN. CHANGES
BEYOND SUNDAY WERE VERY SMALL OR NIL DUE TO TOO MUCH MODEL
UNCERTAINTY. /MELDE
&&
.POINT TEMPS/POPS...
DLH 23 12 24 16 / 20 20 30 20
INL 20 12 23 10 / 20 40 30 10
BRD 25 12 22 15 / 20 20 20 10
HYR 25 14 23 15 / 20 20 20 10
ASX 26 18 26 17 / 40 20 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM CST THIS EVENING FOR
WIZ003-004.
LS...SMALL CRAFT ADVISORY UNTIL 4 AM CST SATURDAY FOR LSZ146-147.
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LSZ121-148.
&&
$$
