Small Craft Advisory 888, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
447 AM AKST SUN NOV 9 2014

.ANALYSIS AND UPPER LEVELS...THE CENTRAL BERING SEA HAS AN UPPER
LEVEL CLOSED LOW WITH THE SURFACE BEING REFLECTED WITH A 950 MB
LOW LOCATED NORTH OF ADAK THIS MORNING. THE STRONGEST WINDS ARE ON
THE BACKSIDE OF THE LOW WITH GUSTY WIND EXTENDING INTO THE SHEMYA
REGION. THE SURFACE OBSERVATIONS THIS MORNING HAVE SLIGHTLY
DIMINISHED AT SHEMYA WITH WIND GUSTS REPORTED UP TO 58 MPH. THE
SATELLITE IMAGERY IS SHOWING SHOWERY PRECIPITATION WITH THIS LOW
ALONG THE WESTERN/CENTRAL ALEUTIANS. THESE SHOWERS ARE SPILLING
OVER INTO THE BERING SEA. THE FRONTAL BOUNDARY ASSOCIATED WITH
THIS LOW PRESSURE SYSTEM HAS MOVED INLAND OVER THE SOUTHWEST
ALASKA REGION EXTENDING THROUGH THE KODIAK ISLAND AREA. THE
SURFACE OBSERVATIONS OVER THE SOUTHWEST REGION HAVE BEEN REPORTING
RAIN SHOWERS WITH SOUTHEASTERLY WINDS WITH GUSTS RANGING FROM 30
TO 40 MPH. THE GULF OF ALASKA HAS AN UPPER LEVEL RIDGE POSITIONED
OVER THE CENTRAL GULF WITH WEAK WINDS UNDER THE RIDGE WITH SOME
MARINE STRATUS. THERE IS A 140 KNOT SOUTH TO NORTH MERIDIONAL JET
STREAK OVER THE ALASKA PENINSULA WITH THE SATELLITE IMAGERY
SHOWING A LARGE SWATH OF MOISTURE SPREADING NORTHWARD INTO KODIAK
ISLAND.

.MODEL DISCUSSION...ALL THE MODELS HAVE INITIALIZED WELL WITH THE
GFS/EC BEING THE PREFERRED MODELS OVER THE BERING SEA. WHILE THE
NAM BEING THE MODEL OF CHOICE FOR THE GULF OF ALASKA THROUGH
SOUTHCENTRAL ALASKA. THE FORECAST CONFIDENCE REMAINS HIGH THROUGH
MONDAY.

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
THERE IS A WEAK SHORTWAVE TROUGH MOVING THROUGH THE PRINCE
WILLIAM SOUND EXTENDING WESTWARD THROUGH THE MATSU VALLEY AREA
THIS MORNING. RADAR IS SHOWING SHOWERY PRECIPITATION WITH THE
ECHOES MOVING NORTHWARD WITH THE SHOWERS CONTINUING TO MOVE
INLAND. THE CHUGACH AND KENAI MOUNTAINS ARE GETTING STRONG
EASTERLY FLOW WHICH IS RESULTING IN DOWNSLOPE DRYING OVER THE
ANCHORAGE BOWL THROUGH THE WESTERN KENAI PENINSULA...BUT THE 500
MB LEVEL IS SHOWING SOUTHERLY WINDS...THIS MAY OFFSET THE LOWER
LEVELS WHICH MAY ALLOW MOISTURE TO ADVECT INTO THE ANCHORAGE BOWL.
THIS WILL RESULT IN THE POSSIBILITY FOR SCATTERED RAIN SHOWERS
FOR THE EARLY MORNING. BY THE AFTERNOON THERE WILL BE A
DISSIPATING WEATHER FRONT THROUGH THE KODIAK ISLAND REGION
EXTENDING INTO THE ALASKA PENINSULA. THIS WILL BRING MORE MOISTURE
WITH STEADY RAIN ALONG THE SOUTH EASTERN KENAI PENINSULA AND THE
SOUTHERN COOK INLET...WITH CONTINUED SCATTERED RAIN SHOWERS
FARTHER NORTH EXTENDING INTO THE ANCHORAGE BOWL FOR THIS
AFTERNOON. BY MONDAY THE FLOW WILL BECOME MORE SOUTHERLY WITH THE
CROSS BARRIER FLOW WEAKENING...WHICH WILL INCREASE THE CHANCES FOR
MORE PRECIPITATION MAKING IT INTO THE ANCHORAGE BOWL AND FARTHER
INLAND AREAS. DUE TO THE GRADIENT STRENGTHENING THE MATANUSKA AND
KNIK WINDS WILL BECOME GUSTY THIS AFTERNOON THROUGH TONIGHT BEFORE
THE WINDS START TO DIMINISH THROUGH THE REGION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 THROUGH 3)...

A NORTH PACIFIC DISTURBANCE WILL CONTINUE TO SPREAD RAIN...MIXED
WITH SOME SNOW ACROSS THE LOWER KUSKOKWIM VALLEY...THROUGH TONIGHT
WITH GENERAL CLEARING FROM WEST TO EAST. STRONG SOUTHEAST WINDS
WILL GRADUALLY WEAKEN THIS EVENING AND TONIGHT. THEREAFTER...A
MORE SHOWERY REGIME WILL DEVELOP UNTIL ANOTHER WIDESPREAD RAIN
EVENT DEVELOPS TUESDAY AFTERNOON INTO WEDNESDAY MORNING.
TEMPERATURES WILL CONTINUE TO REMAIN ABOVE AVERAGE AS STRONG
SOUTHERLY FLOW FROM THE CENTRAL PACIFIC CONTINUES TO TRACK OVER
THE REGION.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 THROUGH 3)...

THE LARGE SPRAWLING WESTERN BERING LOW WILL CONTINUE TO SLOWLY
WEAKEN AND FILL...WITH WIDESPREAD AREAS OF SHOWERS OVERSPREADING
THE BERING AND ALEUTIANS. STRONG WEST SOUTHWEST WINDS ACROSS THE
WESTERN AND CENTRAL ALEUTIANS WILL GRADUALLY WEAKEN THROUGH
MONDAY. SHOWERS WILL GRADUALLY DIMINISH IN COVERAGE THROUGH MONDAY
BEFORE ANOTHER LOW BRINGS WIDESPREAD RAIN TO THE EASTERN
ALEUTIANS.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...
A VERTICALLY STACKED LOW OVER THE NORTHERN BERING WILL CONTINUE
TO WEAKEN THROUGH MID WEEK...AS THE UPPER LEVEL TROUGH CONTINUES
TO ELONGATE AND DIVE SOUTH INTO THE NORTH PACIFIC. FURTHER
EAST...AN AMPLIFYING RIDGE BEGINS TO BUILD FROM THE PANHANDLE
THROUGH THE ALCAN BORDER...AND PERSISTS THROUGH NEXT WEEKEND. THIS
BLOCKING RIDGE WILL KEEP A SERIES OF WEAK BERING AND NORTH PACIFIC
LOWS CONFINED TO THE BERING SEA AND SOUTHWEST MAINLAND. MODELS
HAVE ALL BEEN CAPTURING THIS FEATURE WELL OVER THE PAST FEW
DAYS...CONTINUING TO INCREASE CONFIDENCE IN CLEARING OVER
SOUTHCENTRAL AND THE GULF COAST WITH A WARMING AND DRYING TREND
THROUGH THE LATER PART OF THE WEEK. AFTER FRIDAY...WE BEGIN TO
LOSE CERTAINTY AS MODEL AGREEMENT BEGINS TO WANE WHEN A SIBERIAN
LOW MERGES INTO THE TROUGH OVER THE BERING.

OVER THE BERING SEA AND WESTERN GULF...EXPECT CLOUDY AND SHOWERY
CONDITIONS TO CONTINUE THROUGH MID WEEK WITH WINDS SLOWLY
DIMINISHING THROUGH EARLY NEXT WEEK. GALE FORCE WINDS FROM THE
BERING LOW WILL FINALLY BEGIN TO DIMINISH OVER THE WESTERN
BERING/ALEUTIANS ON TUESDAY. THE WESTERN ALEUTIANS WILL SEE A
QUICK BREAK FROM THE WINDS AND PRECIP ON WEDNESDAY...AS WEAK
RIDGING PASSES THROUGH FROM THE WEST. HOWEVER...A FRONTAL SYSTEM
WILL QUICKLY APPROACH THE WESTERN ALEUTIANS FROM THE WEST BY
THURSDAY...BRINGING PRECIP AND GUSTY WINDS BACK TO THE AREA
THROUGH THE BEGINNING OF THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 120 130 132 136 139 150 165 170 173 174 175 176 177
              178 179 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...PD
SOUTHCENTRAL ALASKA...PD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA
LONG TERM...TP/DEK