Small Craft Advisory 154, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST THU FEB 21 2008

.MODEL DISCUSSION AND UPPER LEVELS...
MODELS IN GOOD AGREEEMENT TODAY. LOOKS AS THOUGH THE GFS/NAM HAS BEEN
HANDLING THE SYSTEMS TODAY RATHER WELL. THE BIG SYSTEMS ARE ALL
PORTRAYED RATHER WELL OVER THE NEXT WEEK. HOWEVER...JUST THE EXACT
POSITIONS ARE IN SLIGHT DISAGREEMENT. THE GFS IS A LITTLE SLOWER AND
KEEPS IT FARTHER SOUTH FOR A LOW IN THE GULF SUNDAY BUT IS FASTER
WITH A LOW RIDING UP TO KAMCHATKA MONDAY NIGHT. IN THE UPPER
LEVELS...A RIDGE IS BUILDING IN THE BERING WITH A CLOSED LOW OVER
KODIAK. THE LOW OVER KODIAK TO ROLL INTO THE CENTRAL GULF AS THE HIGH
BUILDS OVER THE EASTERN BERING SATURDAY AND SUNDAY. THE HIGH BECOME
THE MOST DOMINANT FEATURE AS UPPER LOWS REMAIN IN THE WESTERN BERING
THROUGH NEXT WEEK. THE HIGH IS PUSHED NORTH TO SIBERIA TUESDAY
ALLOWING THE CLOSED LOW IN THE GULF TO SEND A SHORT WAVE EAST AND
BRING MORE WEATHER TO THE SOUTH CENTRAL AND EASTERN BERING TUESDAY
INTO WEDNESDAY. THE HIGH PRESSURE RIDGE DOES REMAIN OVER THE CENTRAL
BERING THOUGH.

.ANALYSIS...
LOW OVER KODIAK ISLAND WITH HIGH PRESSURE OVER THE WESTERN BERING.
THIS IS CREATING STRONG NORTHERLY WINDS OVER THE EASTERN BERING AND
WESTERN COAST OF ALASKA. COMBINED WITH SNOW SHOWERS...SOME LOCAL
AREAS EXPERIENCING BLIZZARD CONDITIONS. THE WINDS AND SNOW SHOWERS
ARE EXPECTED TO DIMINISH LATER TONIGHT WITH BLIZZARD CONDITIONS
ENDING. THE LOW WILL WEAKEN TONIGHT AND DISSIPATE TOMORROW OVER THE
WESTERN GULF. THEREFORE...WINDS WILL BE ON THE DECLINE. A STRONG
FRONT WILL WORK TO THE WESTERN ALEUTIANS IN THE MEANTIME WHILE THE
HIGH PRESSURE MOVES OVER THE CENTRAL AND EASTERN BERING.

IN THE MEANTIME...A STRONG FRONT ALONG THE NORTHERN GULF COAST
CREATING STRONG WINDS. NOT QUITE WARNING CRITERIA...BUT WILL BE
STRONG WITH THE FRONT THROUGH THE EVENING. PRECIP PATTERN WILL
STRONGLY RESEMBLE A DOWNSLOPE EFFECT OVER THE ANCHORAGE AND PALMER
AREAS DURING THIS EPISODE. THE FRONT TO ROLL THROUGH LATE TONIGHT
EARLY TOMORROW WITH PRECIP SPREADING INLAND.

.SHORT TERM FORECAST...
BERING SEA AND ALEUTIANS...
STRONG NORTHERLY FLOW OVER THE EASTERN ALEUTIANS DUE TO THE HIGH OVER
THE WESTERN BERING AND LOW OVER KODIAK. COMBINED WITH SNOW
SHOWERS...SOME LOCAL AREAS RECEIVING BLIZZARD CONDITIONS. THE LOW
OVER KODIAK TO WEAKEN TONIGHT AND DISSIPATE TOMORROW AS THE HIGH
MOVES OVER THE CENTRAL AND EASTERN BERING. THEREFORE...WINDS AND LOW
VISIBILITIES TO DISSIPATE TONIGHT AND TOMORROW MORNING. IN THE
MEANTIME...A LOW WORKS TO THE WESTERN ALEUTIANS WITH A STRONG FRONT.
STORM FORCE WINDS TO REACH THE WESTERN ALEUTIANS WITH THIS FRONT. THE
LOW TO WEAKEN SATURDAY AS IT MOVES AWAY FROM THE JET WHICH REMAINS
NEAR 40N. THE FRONT ALSO DIMINISHES AS WELL. WITH HIGH PRESSURE
ESTABLISHED PRECIP TO REMAIN WEST OF DUTCH HARBOR. THE FRONT REMAINS
IN THE AREA THROUGH SUNDAY MORNING...BEFORE ANOTHER STRONGER LOW
PUSHES TO THE WESTERN ALEUTIANS SUNDAY AFTERNOON. THE FRONT WORKS TO
ADAK AND THAT IS IT BY SUNDAY NIGHT.

WEST OF THE ALASKA RANGE...
STRONG NORTHERLY WINDS ALONG THE COAST AND INTO THE ALASKA PENINSULA
ASSOCIATED WITH THE HIGH OVER THE WESTERN BERING AND LOW OVER KODIAK.
COMBINED WITH SNOW SHOWERS...SOME LOCAL AREAS RECEIVING BLIZZARD
CONDITIONS ALONG THE KUSKO COAST. THESE WINDS TO DIMINISH TONIGHT AND
TOMORROW. ONCE THESE LEAVE THE AREA TOMORROW AFTERNOON...LINGERING
SHOWERS WILL REMAIN ALONG THE MOUNTAINS INTO SATURDAY BEFORE HIGH
PRESSURE SETTLES OVER THE AREA. THEN COLD AND DRY FOR THE REMAINDER
OF THE WEEKEND.

SOUTH AND EAST OF THE ALASKA RANGE...
LOW SITTING OVER KODIAK TODAY WITH A STRONG FRONT ALONG THE NORTHERN
COAST. STRONG SOUTHEAST FLOW OVER THE NORTHERN GULF AND SOUTH
CENTRAL. THIS IS CREATING A LOW OF AREAS WITH STRONG GAP FLOWS.
PRECIP IS IN A TYPICAL DOWNSLOPE PATTERN. THE FRONT TO PUSH THROUGH
TOMORROW MORNING WITH PRECIP SPREADING INLAND. WINDS SHOULD DISSIPATE
AT THIS TIME AS WELL. AT THE SAME TIME...THE LOW OVER KODIAK WILL BE
DIMINISHING TONIGHT AND DISSIPATE OVER THE WESTERN GULF TOMORROW.
SOME LINGERING SHOWERS OVER THE AREA ON SATURDAY. ANOTHER LOW TO MOVE
INTO THE SOUTHEAST GULF SATURDAY NIGHT BUT LITTLE EFFECT ON THE AREA
OTHER THAN SHOWERS IN THE GULF AND NEARBY WESTERN GULF COASTAL
LOCATIONS.

.LONG TERM FORECAST...
00Z ECMWF AND 12Z GFS IN GOOD AGREEMENT THROUGHOUT THE FORECAST. BOTH
MODELS HANDLING THE REX BLOCK OVER THE BERING WELL FOR THIS WEEKEND.
THE HIGH CENTER MOVES TO THE BERING STRAIT EARLY NEXT WEEK. THIS WILL
ALLOW SOME WEATHER TO REACH THE CENTRAL BERING BY MID WEEK.
HOWEVER...HIGH PRESSURE TO KEEP MOST OF THE WEATHER OVER THE GULF AND
BERING AND OUTSIDE OF THE MAINLAND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING ZONES 155 AND 181
MARINE...STORM 176
         GALE 120 155 170 175
FIRE WEATHER...NONE

JN FEB 08