Small Craft Advisory 799, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
512 AM AKST MON DEC 5 2011

.SHORT TERM...THE FRONTAL BAND SLOWLY MOVING SOUTHEAST OVER THE
NORTHEAST GULF COAST AND THE PANHANDLE THROUGH MONDAY AND MONDAY
EVENING. STRONG FLOW IN THE MID TO UPPER LEVELS IS CREATING A LEE
LOW IN THE SOUTHERN YUKON AND DOWN SLOPE WARMING EARLIER WITH
TEMPERATURES TO THE LOWER 50S. THE LOW PRESSURE HAS INCREASED THE
PRESSURE GRADIENT AND LYNN CANAL...AND THE HAINES AND SKAGWAY
REGIONS HAVE BEEN HOWLING THIS MORNING WITH GUSTS TO 50 TO 60 MPH.
STRONG WIND HEADLINES ARE IN EFFECT THERE...THE WINDS SHOULD BE
DECREASING THROUGH THE MORNING.

 THE PRECIPITABLE WATER WITH THE BAND IS OVER NEAR AN INCH AND
RAINFALL AMOUNTS HAVE HAD A GOODLY AMOUNT FALLING OUT. HAVE GONE
WITH SOME LOCALLY HEAVY RAINS THROUGH THE MORNING. AS THE BAND
MOVES SOUTHEAST THE THERE LOOKS TO BE A SHARP CUT OFF OF THE
PRECIPITATION FOLLOWED BY CLEARING. DO EXPECT SOME COOLING
TONIGHT OVER THE NORTHERN PANHANDLE AS COLDER AIR IS FILTERING IN
FROM THE NORTHWEST.

.LONG TERM...LARGE SCALE RIDGING WILL GENERALLY REMAIN OVER THE
ERN PAC THRU NEXT WEEKEND...WITH A LARGER TROF TEMPORARILY
KNOCKING THE RIDGE DOWN AROUND LATE WEEK OVER OUR AREA. MAIN
WEATHER SYSTEMS OF CONCERN WILL BE A MODERATE STRENGTH BUT
WEAKENING OCCLUDED FRONT MOVING IN FOR THU/FRI...THEN A STRONGER
OCCLUDED FRONT FOR THE SUN/MON TIME FRAME THAT WILL BE SIMILAR TO
THE FRONT CURRENTLY AFFECTING THE AREA. MODEL TIMING ON BOTH THE
THU AND SUN/MON FRONTS DIFFERS SOME...ENOUGH TO WARRANT USING A
COMPROMISE SOLUTION LIKE HPC USED. BASICALLY LEFT PRESSURE FIELD
AS IS UNTIL 00Z FRI...WHEN HPC WAS USED FROM THAT TIME OUT TO DAY
8.

 FOR TUE INTO WED...SOME COOLER AIR WILL MOVE IN FROM THE NW.
AIRMASS SOURCE IS NOT ALL THAT COLD RIGHT NOW OVER INTERIOR AK
BUT WILL COOL SOME ONCE CLEARING OCCURS THERE AND OVER THE YUKON
AREA DURING SHORT TERM. MAX TEMPS WILL DROP TO NEAR NORMAL VALUES
FOR TUE. WILL HAVE CLOUDS AROUND WITH WLY ONSHORE FLOW IN
850-700 MB LAYER TUE BUT THEY SHOULD BEGIN TO CLEAR OUT LATER TUE
NIGHT AS FLOW BECOMES MORE NLY. THIS WILL ALLOW GOOD RADIATIONAL
COOLING AS WINDS ARE EXPECTED TO BE FAIRLY LIGHT TUE NIGHT. WED
LOOKS TO BE COLDEST DAY WITH LIGHT WINDS AND MEAGER DECEMBER
SUNSHINE NOT WARMING SFC LAYER MUCH DURING THE DAY.

 THE COLD AIR WILL BE SHALLOW THOUGH...AND IT WILL MODERATE
QUICKLY AS THE FRONT MOVES IN FOR THU. DEPENDING ON TIMING OF
FRONT AND INCREASED WINDS AHEAD OF IT...TEMPS WILL LIKELY BOTTOM
OUT WED EVENING THEN WARM OVERNIGHT INTO THU. PRECIP FROM THIS
FRONT SHOULD REACH THE NE GULF AREA WED NIGHT THEN THE MAIN
PANHANDLE AREA THU. WILL PROBABLY SEE SOME SNOW AT ONSET OF
PRECIP OVER NRN AND FAR ERN INNER CHANNELS...BUT IT SHOULD CHANGE
TO RAIN FAIRLY FAST AS MODERATE TO STRONG SLY FLOW WILL DEVELOP
AHEAD OF THE FRONT.

 AFTER THIS FRONT MOVES THRU...ONLY SLIGHT COOLING IS EXPECTED
BEHIND IT FOR FRI INTO THE WEEKEND. THE SUN/MON FRONT WILL LIKELY
WARM THINGS UP AGAIN AND BRING POTENTIALLY HEAVY RAINFALL TO THE
AREA ALONG WITH FAIRLY STRONG WINDS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 6 AM AKST EARLY THIS MORNING FOR AKZ018-019.
MARINE...GALE WARNING FOR PKZ012-022-031-042-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-013-021-032>036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ053.

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BEZENEK/RWT