Small Craft Advisory 992, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKST SUN DEC 6 2009

.ANALYSIS AND UPPER LEVELS...HIGH AMPLITUDE PATTERN REMAINS IN
PLACE WITH STRONG BLOCKING RIDGE EXTENDING FROM NORTHEAST PACIFIC
TO EASTERN MAINLAND ALASKA AND A TROUGH FROM EASTERN RUSSIA
SOUTHWARD ACROSS THE BERING AND NORTH PACIFIC TO ABOUT 30N LATITUDE.
A 135 KT JET IS FLOWING SE TO NW ACROSS THE ALASKA PENINSULA AND
AROUND THE HIGH AMPLITUDE RIDGE.

AN ESTIMATED 958 MB LOW IS JUST SOUTH OF THE CENTRAL ALEUTIANS WITH
AN ASSOCIATED OCCLUSION STRETCHING SOUTHWARD UNDER THE JET STREAM.
WIDESPREAD STORM FORCE WINDS ARE LOCATED FROM THE NORTH PACIFIC TO
THE BERING SEA WITH HURRICANE GUSTS ALONG THE CHAIN NOT TOO UNCOMMON.

.MODEL DISCUSSION...MODELS ARE IN VERY GOOD AGREEMENT THROUGH
TUESDAY AND FORECAST CONFIDENCE IS HIGH.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
MID TO HIGH LEVEL CLOUDS STILL PERSIST ACROSS SOUTHCENTRAL ALASKA
TODAY BUT AS THE UPPER LEVEL RIDGE AXIS SHIFTS WEST OVER THE NEXT 24
HOURS AS WELL AS SURFACE HIGH PRESSURE  BUILDING OVER THE NORTH GULF
COAST...WE SHOULD START TO SEE THOSE CLOUDS ERODE. ABNORMALLY WARM
AIR ALOFT WILL REMAIN OVER THE REGION THROUGH AT LEAST MID WEEK
RESULTING IN AN INCREDIBLE TEMPERATURE INVERSION WITH TEMPERATURES
BELOW FREEZING AT THE SURFACE BUT WELL INTO THE MID 40S AT BETWEEN
2000 AND 5000 FT. AS THE MID CLOUDS ERODE AWAY...HAVE TO CONSIDER THE
POSSIBILITY OF FOG OR STRATUS DEVELOPING OVERNIGHT UNDER THAT STRONG
INVERSION. AT THIS POINT...THINKING IS THAT IT WILL BE MAINLY ALONG
THE INLET AND NOT WIDESPREAD IF IT DOES DEVELOP.

CONDITIONS REMAIN STAGNANT THROUGH AT LEAST MID WEEK...POSSIBLY NOT
UNTIL THE WEEKEND WHEN THE COLD AIR RETURNS. MODELS HAVE THE RIDGE
AXIS FINALLY SHIFT BACK TO THE WEST ALLOWING A VERY COLD AIRMASS FROM
NORTHERN CANADA TO SPILL SOUTHWEST IN TO THE ALASKA MAINLAND.

SOUTHWEST INTERIOR...THE SOUTHEAST FLOW ACROSS THE ALASKA RANGE IS
RESULTING IN VERY STRONG WINDS AND WARM TEMPERATURES FROM BRISTOL BAY
UP TO THE KUSKOKWIM VALLEY. WIDESPREAD GUSTS TO 50 MPH CAN BE FOUND
IN THIS REGION WITH LOCAL GUSTS AS HIGH AS 65 MPH THROUGH CHANNELED
TERRAIN. THIS WILL CONTINUE THROUGH THE NIGHT AND EARLY MONDAY WHEN
THE UPPER LEVEL SUPPORT SHIFTS WEST AND THE AFFECTS OF THE HIGH
PRESSURE SPREAD OVER THE REGION. CONDITIONS WILL SLOWLY IMPROVE
THROUGH THE WEEK WITH A SLOW DRYING TREND IN ADDITION TO THE
DIMINISHED WINDS.

BERING SEA/ALEUTIANS...THE ACTIVE WEATHER REMAINS OUT WEST WHERE THE
WIND IS SCREAMING AROUND THE LARGE OCCLUDED LOW. GUSTS AS HIGH AS 78
MPH TODAY HAVE BEEN REPORTED AT DUTCH HARBOR WITH FREQUENT GUSTS TO
65 MPH. HIGH WIND WARNINGS FOR THE ALASKA PENINSULA AND EASTERN
ALEUTIANS WILL REMAIN IN AFFECT WHILE A HIGH WIND WATCH FOR THE
PRIBILOFS WILL BE ISSUED WITH THIS AFTERNOONS PACKAGE. A SHORT WAVE
FLOWING TO THE NORTH ALONG THE JET STREAM WILL HELP FOCUS THE WIND
ALONG THE BOUNDARY MONDAY AFTERNOON. WILL ALSO HAVE TO CONSIDER A
WATCH FOR THE WESTERN CAPES UP TO THE KUSKOKWIM DELTA AS GUSTS TO 75
MPH MAY BE POSSIBLE IN THIS REGION AS WELL.

CONDITIONS IMPROVE RAPIDLY LATE MONDAY NIGHT AS ALL OF THE ENERGY
MOVES NORTH. ANOTHER GALE FORCE STORM AND ASSOCIATED BOUNDARY SETS UP
ALONG THE CENTRAL ALEUTIANS WEDNESDAY BUT NOTHING NEARLY AS POTENT AS
THE CURRENT SYSTEM.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 181 185.
         HIGH WIND WATCH 191.
MARINE...STORM WARNING...150 155 160 165 170 172 179 180 185.
         GALE WARNING...132 138 140 171 175 176.
FIRE WEATHER...NONE.

AB DEC 09