Small Craft Advisory 491, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT SUN JUN 3 2007

.MODEL DISCUSSION...
CURRENT MODELS IN FAIR AGREEMENT THROUGH TUESDAY. HOWEVER...THERE ARE
SOME MINOR DIFFERENCES WITH STRENGTH AND EXACTNESS. HAVE DECIDED TO
GO MORE WITH THE NAM/00Z GFS SOLUTION FOR THIS PERIOD. SOME
UNCERTAINTY EXISTS FOR A LOW THAT WILL DEVELOP IN THE GULF TUESDAY.
ALL THE MODELS AND ENSEMBLE MEMBERS FAIRLY CONSISTENT ON THE LOW IN
THE CENTRAL ALEUTIANS INTO THURSDAY. AFTER THURSDAY THOUGH...MUCH
UNCERTAINTY WITH ANY FEATURE OVER THE ALASKA AREA.

.SURFACE ANALYSIS AND FORECAST THROUGH TONIGHT...
LOW DROPPING INTO THE NORTHWEST BERING THIS AFTERNOON WITH ANOTHER
LOW DEVELOPING SOUTH OF ADAK. SOME PRECIPITATION AND SMALL CRAFT
ADVISORY WINDS ASSOCIATED WITH THESE FEATURES THROUGH TONIGHT OVER
THE WESTERN AND CENTRAL ALEUTIANS. IN ADDITION...A LOW IS DEEPENING
OVER THE NORTHEAST PACIFIC NEAR 35N 140W. OVER THE ALASKAN
MAINLAND...A COUPLE OF SHORT WAVE TROUGHS MOVING THROUGH THE AREA.
ONE IS PUSHING THROUGH WESTERN ALASKA THIS MORNING WITH ANOTHER
QUICKLY LEAVING SOUTH CENTRAL THIS AFTERNOON AND THROUGH WESTERN
ALASKA THIS EVENING. THIS WILL BRING ISOLATED TO SCATTERED SHOWERS TO
MANY AREAS. THE ONLY SLIGHT CHANCE FOR CONVECTION IS OVER THE
NORTHERN KUSKOKWIM VALLEY THIS LATE AFTERNOON AND EVENING.

.UPPER LEVELS...
CURRENTLY THERE IS A LARGE TROUGH EXTENDING FROM NORTHWEST TO
SOUTHEAST ACROSS THE BERING SEA TOWARD THE NORTHEAST PACIFIC SOUTH OF
THE GULF. A LARGE AMPLITUDE RIDGE IS OVER THE PLAINS OF THE LOWER 48
EXTENDING BACK TO THE YUKON. ADDITIONALLY...A LOW IS ANCHORED NEAR
NORTHERN RUSSIA WITH ANOTHER OVER THE NORTHERN ATLANTIC AS WELL. THE
LOW OVER THE ATLANTIC MOVES NEAR HUDSON BAY BY TUESDAY WITH THE
TROUGH OVER THE BERING BECOMING MORE OF A CLOSED FEATURE AT THIS
TIME. THE STRENGTH OF THESE TWO FEATURES CUTS OFF THE RIDGE OVER THE
YUKON AND SENDS A CLOSED HIGH TO THE BEAUFORT SEA. THIS MEAN PATTERN
REMAINS ROUGHLY THE SAME THROUGH THE WEEK. MORE OR LESS THE EC AND
UKMET AGREE EXCEPT THE HUDSON BAY LOW DRIFTS FARTHER WEST LATE IN THE
WEEK IN THEIR SCENARIOS. THE MESS IS IN THE DETAILS OF EACH SHORT
WAVE WORKING AROUND THIS UPPER LEVEL PATTERN.

.SHORT TERM FORECAST...
.EAST OF THE ALASKA RANGE...
LOW PRESSURE SYSTEM MOVING INTO THE GULF LATE TONIGHT WITH A FRONT
PUSHING TO PRINCE WILLIAM SOUND MONDAY MORNING. A SHORT WAVE AHEAD OF
THE FRONT TO BRING A SHOT OF SCATTERED PRECIPITATION TO SOUTH CENTRAL
LATE TONIGHT AND EARLY MONDAY MORNING. IN ADDITION...ENOUGH WARMING
AHEAD OF THE FRONT FOR AN UNSTABLE AIR MASS. MAY SEE SOME
THUNDERSTORMS MONDAY AFTERNOON AHEAD OF THE FRONT. THE FRONT WILL
BRING A BURST OF STRONG WIND WITH A RIDGE BUILDING ALONG THE COAST
BEHIND IT. THE FRONT IS SUPPORTED BY A STRONG JET. SMALL CRAFT TO
GALE FORCE WINDS ACROSS THE NORTHERN GULF TO POINTS INLAND WILL BE
ASSOCIATED WITH FRONT. STRONG WINDS WILL ALSO PUSH THROUGH EAST WEST
GAPS MONDAY EVENING. THE PRESSURE GRADIENT RELAXES A BIT MONDAY NIGHT
BUT RE-ESTABLISH TUESDAY FOR CONTINUED GAP WINDS THROUGH WEDNESDAY.
HOWEVER...WIND GUSTS WILL NOT LIKELY BE AS STRONG AS THE ONES
EXPECTED WITH THE FRONT MONDAY EVENING. THE FRONT WILL SWING TO
KODIAK MONDAY EVENING WITH STRONG WINDS AS WELL. THE LOW WILL WEAKEN
MONDAY NIGHT AND THEN DISSIPATE TUESDAY AS A RIDGE BUILDS OVER THE
GULF. PRECIPITATION WILL BE BRIEF WITH THE FRONT...BUT HEAVY AT
TIMES. AFTER THE FRONT...MOST PRECIPITATION WILL BE SHOWERS ALONG THE
COAST THROUGH TUESDAY. MOSTLY DRY CONDITIONS WILL BE PRESENT
WEDNESDAY EXCEPT A WEAK FRONT WILL APPROACH KODIAK.

.WEST OF THE ALASKA RANGE...
HIGH PRESSURE OVER THE EASTERN BERING AND SOUTHWEST ALASKA TO BE
PUSHED NORTH AS THE LOW IN THE GULF MOVES TO KODIAK MONDAY AFTERNOON.
IN ADDITION...THE LOW SOUTH OF THE CENTRAL ALEUTIANS DEEPENS AND
MOVES CLOSER TO THE CHAIN. THE FRONT FROM THE GULF LOW TO SPREAD OVER
SOUTHWEST ALASKA MONDAY NIGHT. WARMING AHEAD OF THE FRONT WILL ALSO
MEAN A FEW THUNDERSTORMS ARE POSSIBLE MONDAY AFTERNOON OVER SOUTHWEST
ALASKA. SOME MODERATE WINDS TO PUSH WITH THE FRONT MONDAY NIGHT.
HOWEVER...THE FRONT WILL WEAKEN AS IT MOVES TO THE KUSKOKWIM VALLEY
MONDAY MORNING. BY MONDAY MORNING...THE LOW OVER THE CENTRAL
ALEUTIANS TO BEGIN SLOWLY MOVING EAST THROUGH WEDNESDAY. WITH HIGH
PRESSURE TO THE NORTH...MODERATE EASTERLY WINDS WILL BE OVER THE
BERING. AFTER THE FRONTAL PASSAGE MONDAY NIGHT...MOST ACTIVITY WILL
BE DIURNAL SHOWER ACTIVITY OVER THE MAINLAND. A FRONT FROM THE
CENTRAL ALEUTIAN LOW TO MOVE FROM DUTCH TOWARD THE ALASKA PENINSULA
TUESDAY AFTERNOON THROUGH WEDNESDAY WITH SOME ORGANIZED
PRECIPITATION.

.LONG TERM FORECAST...
WITH THE UNCERTAINTY...THE OVERALL PATTERN SUGGESTS UNSETTLED WEATHER
THROUGH THE GULF...BERING...AND ALEUTIAN CHAIN. WARMER AND SOMEWHAT
DRIER WEATHER OVER THE INTERIOR. THIS WOULD POSSIBLY LEAD TO SOME
CONVECTIONS WITH A THERMAL TROUGH DEVELOPING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 130
FIRE WEATHER...NONE

JN JUN 07