Small Craft Advisory 466, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
144 PM AKDT THU JUN 12 2014

.ANALYSIS AND UPPER LEVELS...

A WEAK FRONTAL SYSTEM STRETCHING ACROSS SOUTHWEST ALASKA TO OVER
THE WESTERN GULF BROUGHT SOME LIGHT RAIN TO SW ALASKA...WESTERN
SUSITNA VALLEY...AND THE KENAI PEN. MARINE STRATUS ALSO DEVELOPED
OVER COOK INLET AND BROUGHT LOW CEILINGS AS FAR NORTH AS THE
ANCHORAGE BOWL THIS MORNING. THE THERMAL TROUGH OVER THE INTERIOR
WAS SHOWING SIGNS OF STRENGTHENING THIS AFTERNOON UNDER RELATIVELY
FAIR SKIES. A WEAKENING LOW WAS EVIDENT OVER THE EASTERN BERING
SEA WITH A SECONDARY LOW DEVELOPMENT SOUTH OF THE EASTERN
ALEUTIANS.

&&

.MODEL DISCUSSION...

MODELS OVERALL ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM OVER
SOUTHCENTRAL AND THE GULF. FURTHER WEST MODELS ARE IN RELATIVELY
GOOD AGREEMENT THROUGH SAT AFTERNOON. THE ECMWF AND GEM GLOBAL
DIG OUT THE UPPER TROUGH AND MOVE THE UPPER CENTER SOUTH OF THE
ALEUTIANS ON SUN. IN RESPONSE...A SURFACE CENTER DEVELOPS OVER THE
NE PACIFIC AND MOVES SOUTH OF THE EASTERN AK PEN SUN AFTERNOON.
THE GFS/NAM ARE SLOWER ON MOVING THE UPPER CENTER SOUTH OF THE
ALEUTIANS AND PUT MORE EMPHASIS ON THE SURFACE DEVELOPMENT IN THE
PROXIMITY OF THE UPPER CENTER. THE ECMWF HAS SHOWN GREATER RUN TO
RUN CONSISTENCY WITH THIS FEATURE. SO WILL LEAN TOWARD A BLEND OF
THE OFFICIAL AND 12Z EC RUN WITH THIS FORECAST PACKAGE.

SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
A WEAK FRONT OVER THE WESTERN GULF THIS MORNING MOVES NORTH AND
WEAKENS THROUGH THIS EVENING. A SECONDARY FRONT ASSOCIATED A
DEVELOPING LOW SOUTH OF THE AK PEN SPREADS RAIN FROM KODIAK
ISLAND TO OVER SOUTHCENTRAL TONIGHT. THE BRUNT OF THE RAIN WILL
LIKELY BE ALONG THE COAST AND SOUTHEAST EXPOSURES. THERE WILL
LIKELY BE A LITTLE BIT OF A MOISTURE SURGE UP THE INLET TONIGHT
WHICH COULD BRING A LITTLE MORE WIDESPREAD RAIN INTO THE ANCHORAGE
BOWL BEFORE THE FLOW ALOFT SHIFTS EAST AND THE DOWNSLOPE KICKS IN.
RAIN WILL LIKELY CONTINUE ALONG THE COAST THROUGH FRI WHILE
BECOMING MORE SHOWERY INLAND. CHANCES OF SHOWERS/RAIN WILL
CONTINUE INTO THROUGH THE WEEKEND AS EASTERLY WAVES MOVE ACROSS
THE MAINLAND. BY NATURE EASTERLY WAVES CAN BE DIFFICULT TO
FORECAST...HOWEVER THE MODELS ARE HINTING AT A POTENTIAL FOR A
MORE WIDESPREAD RAIN FROM COPPER RIVER BASIN TO THE ANCHORAGE BOWL
ON SAT. PRESSURE GRADIENTS BUILDING ALONG THE NORTH GULF THIS
AFTERNOON IN COMBINATION WITH A STRENGTHENING INTERIOR THERMAL
TROUGH WILL PRODUCE GUSTY SOUTH WINDS ALONG THE COPPER RIVER THIS
AFTERNOON AND EVENING. WINDS IN ADVANCE OF THE FRONT MOVING INTO
THE GULF TONIGHT WILL BRING GALES TO THE NORTH AND WESTERN
GULF...WINDS THEN WEAKENING ON FRI.

SOUTHWEST ALASKA...
RAIN WILL LIKELY CONTINUE OVER THE AREA TONIGHT AS FRONT WEAKENS
AS IT MOVES NORTH AND THE WESTERN EDGE OF A FRONT MOVING INTO THE
GULF TONIGHT IMPACTS BRISTOL BAY. RAIN SHOULD GIVE WAY TO SOME
CLOUD BREAKS AND SHOWERS FRI AND SAT AS THE FLOW BECOMES MORE
NORTHWESTERLY.

BERING SEA/ALEUTIANS...THE LOW OVER THE CENTRAL BERING SEA WILL
BRING RAIN SHOWERS TO THE CENTRAL AND EASTERN ALEUTIANS TODAY
BEFORE GRADUALLY TAPERING OFF FROM WEST TO EAST LATE TONIGHT INTO
FRIDAY. ONCE THE LOW PUSHES INTO THE GULF...COLD AIR WILL DROP
SOUTH FROM THE ARCTIC AND FROM RUSSIA...STRENGTHENING THE PERSISTENT
LONGWAVE TROUGH OVER THE BERING SEA. WITH THE COLDER AIR ALOFT AND
WARMER TEMPERATURES OVER THE CENTRAL AND ALEUTIAN ISLANDS...CONVECTIVE
SHOWERS WILL BE POSSIBLE THROUGH THE REMAINDER OF THE SHORT TERM.

LONG TERM FORECAST (SUN THROUGH THU)...
DETERMINISTIC AND ENSEMBLE MEMBERS ARE IN GOOD AGREEMENT THROUGH
MONDAY AFTERNOON WITH AN AMPLIFIED TROUGH EXTENDING FROM THE
CENTRAL ALEUTIANS ACROSS SOUTHCENTRAL ALASKA AND INTO THE
PANHANDLE. THE MODELS DIFFER ON THE STRENGTH OF A PACIFIC NORTH
AMERICAN RIDGE OVER THE WEST COAST OF THE CONUS...WHICH WILL
IMPACT THE EXACT TRACK AND PLACEMENT OF THE TROUGH. REGARDLESS OF
THE SOLUTION...IT LOOKS LIKE A WET AND COOL PERIOD REMAINS LIKELY
WITH MULTIPLE SHORT WAVES BEING EJECTED OVER SOUTHERN ALASKA AND A
COLD UPPER LOW SLOWLY MEANDERING THROUGH THE REGION.

AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 130 131 132 138 150 351 352.
FIRE WEATHER...NONE.
&&

RMC JUN 14