Gale Warning 602, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKDT SAT OCT 25 2008

.ANALYSIS AND UPPER LEVELS...
A RELATIVELY TRANQUIL SETUP OVER THE FORECAST AREA THIS MORNING. A
BROAD MID TO UPPER TROUGH IS PRESENT...ROUNDED OUT BY THE JET STREAM
GOING SOUTHEAST FROM SIBERIA TO THE WESTERN ALEUTIANS AND TO
40N...THEN HEADING NORTHEAST TO SOUTHEAST ALASKA. COLDER THAN NORMAL
TEMPERATURES ENCOMPASS NEARLY THE ENTIRE FORECAST AREA. LOOKING A
BIT CLOSER...A 1010 MB SURFACE LOW IS PRESENT THIS MORNING JUST
NORTH OF DUTCH HARBOR. THIS LOW DISSIPATES TODAY AS IT ABSORBED INTO
A STRONGER LOW FORMING IN THE FAR SOUTHERN GULF ALONG THE JET STREAM.
ALSO OF INTEREST IS A WEAK SHORTWAVE IN SOUTHWEST FLOW BRINGING SOME
LIGHT WARM ADVECTIVE SNOW TO THE COOK INLET REGION AND BRISTOL BAY
AREA TODAY.

.MODEL DISCUSSION...
MODELS ARE IN DECENT AGREEMENT OVERALL. MODELS HAVE COME INTO FAIRLY
GOOD AGREEMENT ON THE SIGNIFICANT LOW MOVING NORTHEAST THROUGH THE
GULF THROUGH THE SHORT TERM. THERE ARE STILL SOME SMALL ISSUES WITH
THE SPEED OF THE LOW AND THE EXACT TRACK.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
WARM ADVECTION UP COOK INLET ALONG WITH SOUTHWEST UP INLET BREEZES
KEPT TEMPERATURES FROM GETTING NEARLY AS COLD AS THEY COULD HAVE
FROM PALMER TO ANCHORAGE AND THE KENAI PENINSULA. TEMPERATURES DID
HOWEVER DIP BELOW ZERO OVER PORTIONS OF THE SUSITNA VALLEY AND
COPPER RIVER BASIN. FOR TODAY AND THIS EVENING...SOME LIGHT SNOW
WILL ACCOMPANY THIS WARM ADVECTION FROM THE SOUTHWEST...WITH SNOW
POSSIBLE MAINLY FROM THE TALKEETNA AND CHUGACH MOUNTAINS WEST.

A FAIRLY STRONG LOW PRESSURE IS DEVELOPING THIS MORNING IN THE NORTH
PACIFIC. THIS LOW WILL STRENGTHEN TO 986 MB THIS AFTERNOON AS IT
MOVES TO 350 NM SOUTH OF KODIAK CITY. THE LOW THEN GRADUALLY WEAKENS
AS IT MOVES TO JUST SOUTHEAST OF CORDOVA LATE SUNDAY NIGHT AND
STALLS OUT. STRONG 55 KT WINDS ARE EXPECTED WITH A FRONT MOVING OUT
AHEAD OF THE LOW...WITH THE STORM FORCE WINDS ENCOMPASSING MUCH OF
THE GULF ABSENT THE INNER WATERS TONIGHT AND SUNDAY. AREAS WEST AND
NORTH OF A LINE FROM THE MIDDLE OF THE KENAI PENINSULA TO ANCHORAGE
TO GULKANA SHOULD REMAIN DRY FROM THIS SYSTEM. ONE OF THE MORE
SIGNIFICANTLY AFFECTED AREAS WILL BE KODIAK WHICH WILL SEE STRONG
NORTHEAST WINDS AND A RAIN SNOW MIX AS THE LOW PASSES SOUTHEAST OF
KODIAK. CORDOVA AND VALDEZ WILL HAVE A STRONG OFFSHORE PRESSURE
GRADIENT AND WITH VERY COLD AIR OVER THE COPPER RIVER BASIN...WILL
HAVE TO WATCH FOR LOCALLY GUSTY WINDS SUNDAY AND MONDAY FOR
CHANNELED TERRAIN FROM VALDEZ TO CORDOVA. COLD ADVECTION WILL RETURN
FOR ALL OF SOUTHCENTRAL SUNDAY AND MONDAY AS THE FLOW SHIFTS
OFFSHORE OVER THE AREA IN RESPONSE TO THE NORTHEASTWARD MOVEMENT OF
THE LOW TOWARD CORDOVA. VERY COLD TEMPERATURES WILL PERSIST INTO
TUESDAY AT LEAST.

SOUTHWEST MAINLAND...
COMPLEX SETUP OVER THE SOUTHWEST MAINLAND TODAY. A WEAK FRONT
EXTENDS EAST INTO BRISTOL BAY FROM A LOW NEAR DUTCH
HARBOR...BRINGING SOME LIGHT SNOW TO THE AREA. MEANWHILE...A WEAK
SYSTEM AROUND NORTON SOUND IS GRAZING THE KUSKOKWIM VALLEY WITH SOME
LIGHT SNOW THERE AS WELL. THE CORRIDOR FROM THE KUSKOKWIM DELTA TO
THE NUSHAGAK HILLS IS IN A COL IN BETWEEN THE SYSTEMS. EVERYTHING
WILL BASICALLY TRANSITION INTO NORTHERLY FLOW THIS AFTERNOON AND
TONIGHT IN RESPONSE TO THE STRONG LOW MOVING TOWARD KODIAK FROM THE
SOUTH. HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE WEST ON
MONDAY WITH VERY COLD TEMPERATURES CONTINUING ESPECIALLY IN THE
KUSKOKWIM VALLEY.

BERING SEA/ALEUTIANS...
A WEAK LOW JUST NORTH OF DUTCH HARBOR THIS MORNING WILL DISSIPATE
TODAY AS IT IS ABSORBED INTO THE STRONGER LOW MOVING NORTH TOWARD
KODIAK. A PROGRESSIVE RIDGE OF HIGH PRESSURE OVER THE WESTERN
BERING/ALEUTIANS TODAY WILL MOVE EAST TO THE CENTRAL
BERING/ALEUTIANS ON SUNDAY AND TO THE ALASKA PENINSULA MONDAY. COOL
TEMPERATURES ALONG WITH A FEW SHOWERS WILL CONTINUE FOR AREAS ALONG
AND EAST OF THE RIDGE OF HIGH PRESSURE. A STRONG FRONT WILL MOVE
INTO THE WESTERN BERING/ALEUTIANS SUNDAY AND SUNDAY NIGHT. THIS
SYSTEM WILL PROGRESS EAST THROUGH THE BERING/ALEUTIANS THROUGH
TUESDAY...BRINGING GENERALLY GALE FORCE WINDS AND WARMER
TEMPERATURES WITH RAIN.

.LONG TERM FORECAST...
A BLOCKING AREA OF HIGH PRESSURE IS EXPECTED TO PERSIST OVER THE
MAINLAND THROUGH THE REST OF THE WEEK WITH GENERALLY DRY AND COLD
CONDITIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING ZONES 120 130 132 150 351 352.
         GALE WARNING ZONES 138 176.
FIRE WEATHER...NONE.

FOISY OCT 08