FXUS63 KDLH 050304 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
904 PM CST THU DEC 4 2008

.UPDATE...BUMPED UP MIN TEMPS WITH WAA UNDERWAY AND CI SHIELD
APPROACHING FROM THE NW AHEAD OF CLIPPER SYSTEM. REMOVED POPS
ALONG THE SOUTH SHORE AS SFC WIND IS WSW AND AFOREMENTIONED WAA.
DID LEAVE A MENTION OF FLURRIES HOWEVER.

&&

.PREV DISCUSSION... /ISSUED 318 PM CST THU DEC 4 2008/

DISCUSSION...MAIN FORECAST CHALLENGES ARE ENDING LES EVENT AND
CLIPPER SYSTEM FOR FRIDAY NIGHT. AFTERNOON WATER VAPOR LOOP SHOWS
DEEP COLD CORE TROUGH CONTINUING TO SINK SOUTHEAST OVER THE UPPER
MIDWEST/WESTERN GREAT LAKES. SURFACE WINDS HAVE BACKED
WESTERLY...AND WILL CONTINUE TO DO SO THIS EVENING AS THE UPPER
TROUGH PUSHES EASTWARD. AS A RESULT...LAKE EFFECT SNOW BANDS
SHOULD CONTINUE TO MIGRATE EASTWARD...OUT OF THE FA...DESPITE
CONTINUED COLD AIRMASS IN PLACE OVER WESTERN LAKE SUPERIOR /H85
TEMPS AROUND -20C ATTM/. LET WARNING EXPIRE AS SCHEDULED
ACCORDINGLY. OTHERWISE...CONVECTIVE CLOUD STREETS ALONG WITH SCT
FLURRIES/SHSN WILL DIMINISH THIS EVENING AND OVERNIGHT...SETTING
UP A COLD NIGHT FOR THE NORTHLAND. WINDS OF 5 TO 10 MPH ALONG WITH
SFC LOWS REACHING THE SINGLE DIGITS ABOVE AND BELOW ZERO WILL
RESULT IN WIND CHILLS IN THE 10 TO 20 BELOW ZERO RANGE FOR LATE
TONIGHT AND FRIDAY MORNING. SHOULD SEE A FAIRLY GOOD RECOVERY OF
TEMPS FRIDAY AHEAD OF NEXT APPROACHING ALBERTA CLIPPER SYSTEM.

FORECAST ATTENTION THEN TURNS POSITIVELY TILTED TROUGH DIVING
SOUTHEAST FRIDAY EVENING THROUGH THE OVERNIGHT ACROSS THE DLH FA.
THIS SYSTEM LOOKS TO BRING GENERALLY 1 TO 3 INCHES TO THE
NORTHLAND...WITH THE HIGHEST AMOUNTS INTO NORTHWEST WISCONSIN WHERE
STRONGEST 2-D FGEN OCCURS LATE FRIDAY NIGHT PER NAM. GUSTY WINDS
ALONG WITH THIS EVENT BEING THE FIRST WIDESPREAD ACCUMULATING SNOW
WILL MAKE FOR SOME TRAVEL PROBLEMS INTO SATURDAY MORNING. A LES
EVENT LOOKS LIKELY ONCE AGAIN FOR THE SOUTH SHORE WITH A GUSTY
NORTHWEST WINDS...AND H85 TEMPS DROPPING TO NEAR -20C SATURDAY
THROUGH SATURDAY NIGHT.

EXTENDED...SUNDAY THROUGH THURSDAY
EXTENDED PERIOD WILL BEGIN WITH BRIEF RIDGING ON SUNDAY...WITH LAKE
EFFECT SNOWS DIMINISHING OVER NW WISCONSIN...AND DRY WEATHER
ELSEWHERE. WAA AND ISENTROPIC LIFT WILL BRING INCREASING CLOUDS AND
SNOW CHANCES BY SUNDAY NIGHT INTO MONDAY...GENERALLY FROM WEST TO
EAST. WHILE DEEP MOISTURE WILL BE LIMITED...SOME LIGHT TO MODERATE
SNOW ACCUMULATIONS CERTAINLY APPEAR POSSIBLE. WEAK HIGH PRESSURE
WILL THEN RETURN LATE MONDAY INTO EARLY TUESDAY...EXCEPT FOR SOME
LINGERING LIGHT SNOW OVER OUR EASTERN ZONES. ANOTHER CLIPPER SYSTEM
WILL BRING A ROUND OF LIGHT SNOW TO MUCH OF THE REGION ON
WEDNESDAY...BEFORE A MORE POTENT SYSTEM APPROACHES FROM THE
SOUTHWEST LATE WEDNESDAY INTO THURSDAY. MODELS ARE IN A BIT OF
DISAGREEMENT...BUT GENERALLY PREFER THE GFS AND GFS
ENSEMBLES...WHICH DO NOT SUPPORT SIGNIFICANT PHASING OF THE NORTHERN
AND SOUTHERN BRANCHES OF THE JET OVER THE PLAINS. THIS WOULD
EFFECTIVELY KEEP THE LOW WEAKER AND A TAD FURTHER SOUTH.
OTHERWISE...COLD AND BELOW NORMAL TEMPERATURES WILL PREVAIL THROUGH
THE PERIOD WITH A DEEP H5 TROUGH CENTERED NEAR HUDSON BAY. THE
COLDEST TEMPERATURES ARE LIKELY WEDNESDAY INTO THURSDAY...WITH H85
TEMPS OF -20C TO -24C. HOWEVER....THE GFS SUGGESTS TEMPERATURES WILL
BEGIN TO WARM SLIGHTLY BY LATE THURSDAY AND BEYOND AS THE THE TROUGH
SLOWLY PUSHES OFF TO THE NORTH AND EAST. WE BELIEVE THIS MAY BE A
BIT FAST...ESPECIALLY WHEN CONSIDERING OTHER MODEL GUIDANCE...AND
ONLY WARMED TEMPERATURES SLIGHTLY.

AVIATION...LOW VFR AND MVFR CEILINGS WILL PREVAIL THROUGH 18Z
FRIDAY. SCATTERED SNOW SHOWERS WILL ALSO PERSIST THROUGH 00Z THIS
EVENING...AND MAY ALSO BRING VSBYS AS LOW AS 2SM. THE RUC13 AND
NAM12 SUGGEST A TEMPORARY RISE IN CEILING HEIGHTS AND MAINLY
SCATTERED CLOUDS FOR SOUTHERN AREAS INCLUDING KBRD DURING THE
EVENING HOURS...FROM 00Z TO 06Z...BEFORE MVFR AGAIN BECOMES MORE
PREVALENT AFTER 06Z. WARM AIR ADVECTION WILL SPREAD MID LEVEL CLOUDS
INTO THE REGION ON FRIDAY MORNING...AHEAD OF AN APPROACHING
SHORTWAVE...BUT CEILINGS WILL REMAIN MOSTLY LOW VFR THROUGH
18Z...BEFORE DETERIORATING TO MVFR FROM NORTHWEST TO SOUTHEAST IN
LOW CLOUDS AND LIGHT SNOW FRIDAY AFTERNOON.

&&

POINT TEMPS/POPS...
DLH 4 18 11 16 / 10 20 80 30
INL 4 15 1 8 / 10 40 80 20
BRD 3 21 14 17 / 10 20 80 20
HYR 4 19 13 20 / 10 10 80 40
ASX 7 18 11 19 / 10 20 80 50

&&

.DLH WATCHES/WARNINGS/ADVISORIES...

MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST FRIDAY FOR LSZ121-LSZ146-
LSZ147-LSZ148.


$$

GSF



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