Small Craft Advisory 972, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST SUN DEC 7 2008

RETRANSMISSION

.ANALYSIS AND UPPER LEVELS...

MASSIVE UPPER LEVEL RIDGE BETWEEN KAMCHATKA AND THE CENTRAL ALEUTIANS
EXTENDS NORTH TO THE POLE AND SOUTH TO 30 N THIS MORNING. A BROAD
UPPER TROUGH EXTENDS FROM THE CENTRAL ALEUTIANS TO NEAR YAKUTAT...
WITH AN EMBEDDED CUT-OFF LOW WELL SOUTH OF NIKOLSKI. A WEAKER UPPER
LOW IS OVER THE NORTHERN GULF. AT THE SURFACE...A LOW OVER NORTHERN
KAMCHATKA IS ASSOCIATED WITH A WEATHER FRONT JUST WEST OF
SHEMYA...HIGH PRESSURE IS ENTRENCHED OVER THE CENTRAL ALEUTIANS AND
BERING...AND A WEAK LOW IS OVER THE KENAI PENINSULA. A LOW CURRENTLY
650 NM SOUTH OF COLD BAY WILL BE THE WEATHER MAKER FOR MOST OF THE
FORECAST AREA FOR THE NEXT SEVERAL DAYS.

.MODEL DISCUSSION...MODELS AGREE THAT THE UPPER RIDGE WILL BREAK DOWN
AND THE LOW SOUTH OF NIKOLSKI WILL MOVE TOWARD THE AKPEN AND KODIAK
ISLAND. THE UKMET AND GFS HAVE THE LOW MOVING ACROSS SOUTHERN KODIAK
INTO THE AKPEN MON NIGHT...WHILE THE NAM MOVES THE LOW INTO THE
CENTRAL GULF. THE EC MOVES THE LOW EAST OF KODIAK ISLAND AND INTO THE
KENAI. SINCE THE EC HAS BEEN MOST CONSISTENT OVER THE PAST SEVERAL
RUNS THE FORECAST IS BASED ON ITS COMPROMISE SOLUTION.

.SHORT TERM FORECAST...

IN THE WEST A WEATHER FRONT WILL BRING GALES AND SMALL CRAFT ADVISORY
WINDS TO THE WESTERN ISLANDS TODAY AND TONIGHT BEFORE DISSIPATING
OVER THE CENTRAL ALEUTIANS. RAIN WILL CHANGE TO SNOW SHOWERS WHICH
PERSIST THROUGH WED. THE EASTERN ISLANDS WILL BE UNDER THE INFLUENCE
OF THE WESTERN FLANK OF THE NORTHERN GULF LOW. THIS WILL KEEP FOG AND
A MIX OF RAIN AND SNOW AND ISOLATED PATCHES OF FREEZING RAIN OVER THE
AREA TODAY. BY TONIGHT NORTHEAST FLOW AHEAD OF THE NIKOLSKI LOW WILL
SPREAD RAIN ALONG WITH GALE FORCE WINDS TO THE EASTERN ISLANDS THAT
WILL PERSIST INTO MON NIGHT. AT THAT TIME COLDER AIR AND NORTHWEST
FLOW WILL ALLOW FOR SNOW SHOWERS TO SPREAD ACROSS THE ENTIRE BERING
AND CONTINUE INTO MID WEEK.

FOR SOUTHWEST AK THE WESTERN FLANK OF THE GULF LOW WILL KEEP SOME
SNOW SHOWERS OVER THE AREA TODAY...AFTER PATCHY FREEZING RAIN.
CONDITIONS WILL IMPROVE BY LATE AFTERNOON WITH AT LEAST PARTIAL
CLEARING TONIGHT. AS THE LOW SOUTH OF NIKOLSKI MOVES INTO THE WESTERN
GULF MON AFTERNOON...RAIN SHOWERS WILL CROSS THE ALEUTIAN RANGE INTO
THE BRISTOL BAY ZONE..CHANGING TO SNOW SHOWERS OVER THE KUSKOKWIM
VALLEY TUE. THE KUSKOKWIM DELTA WILL REMAIN NORTHWEST OF THE
PRECIPITATION AREA THROUGH MID WEEK.

SOUTH AND EAST OF THE AK RANGE...WARM AIR ALOFT OVER COLDER SURFACE
CONDITIONS WILL CREATE AREAS OF LIGHT FREEZING RAIN THIS MORNING OVER
ANCHORAGE AND THE MATANUSKA VALLEY. AS THE GULF LOW DISSIPATES AND
MOVES EAST THIS AFTERNOON...IT WILL DRAW COLDER AIR ALOFT INTO THE
AREA AND CHANGE THE FREEZING RAIN TO SNOW SHOWERS THAT DIMINISH
TONIGHT. MEANWHILE LIGHT AMOUNTS OF SNOW WILL FALL OVER THE COPPER
RIVER BASIN THROUGH MON. ON MON THE LOW MOVING TOWARD KODIAK ISLAND
WILL BRING RAIN TO THE ISLAND AND HEAVIER AMOUNTS TO THE GULF
COAST...ALONG WITH STORM FORCE WINDS TO ALL ZONES ALONG THE COAST.
SNOW WILL REACH SOUTH CENTRAL TUE INTO WED.

.LONG TERM FORECAST...

IN THE WEST A DRYING RIDGE WILL MOVE RAPIDLY ACROSS THE BERING ON
THU. THE NEXT SIGNIFICANT PACIFIC LOW WILL THEN BRING STORMS TO THE
ENTIRE BERING FOR THE END OF THE WEEK. SOUTHWEST AK WILL HAVE A FEW
SHOWERS AHEAD OF THE RIDGE...AND THEN PARTIAL CLEARING FOR THE
REMAINDER OF THE WEEK. SOUTH AND EAST OF THE AK RANGE...SNOW SHOWERS
WILL AFFECT THE AREA THROUGH THU. A LOW MOVING FROM SE AK WILL THEN
BRING MORE PRECIPITATION TO COASTAL SECTIONS AND THE COPPER RIVER FOR
THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORMS 120 130 132 138
         GALES 125 140 141 150 155 160 165 170 172 175 176 185
         HEAVY FREEZING SPRAY WARNING 160 180 185
FIRE WEATHER...NONE

DS DEC 08