Small Craft Advisory 443, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
412 PM AKDT SAT MAY 23 2015

.ANALYSIS AND UPPER LEVELS...
THE AMPLIFIED RIDGE WHICH HAS BEEN HOLDING OVER THE GULF/EASTERN
ALASKA OVER THE LAST WEEK OR SO HAS MOVED A LITTLE BIT TO THE
EAST. THIS HAS ALLOWED A COUPLE OF TROUGHS STRETCHING SE ACROSS
SW ALASKA AND WESTERN GULF TO PUSH THE MEAN BAROCLINIC ZONE
FURTHER EAST AND BRING CLOUDS AND RAIN ACROSS THE KENAI PENINSULA
AND COOK INLET REGION. THE FURTHER WEST MOST TROUGH IS BRINGING
LIGHT RAIN ACROSS THE SW MAINLAND...MOST NOTABLY THE BRISTOL BAY
REGION. WIDESPREAD CLOUDINESS WITH AREAS OF RAIN CONTINUES ACROSS
MUCH OF THE REMAINDER THE THE BERING SEA...ALEUTIANS...AND AK PEN.
STRONG SOUTHERLY WINDS ARE EVIDENT ACROSS THE AK PEN AND EASTERN
BERING SEA WITH BRISK WESTERLY WINDS ACROSS THE ALEUTIANS. OLD
TYPHOON DOLPHIN OVER THE WEST CENTRAL BERING SEA HAS BOTTOMED OUT
AND SHOULD BE SLOWLY WEAKENING. THE FIRE WEATHER THREAT CONTINUES
HIGH ACROSS MUCH OF THE COPPER RIVER BASIN THIS EVENING AS
GENERALLY SUNNY SKIES AND WARM TEMPS ARE EXPECTED THIS AFTERNOON.
IN ADDITION TO THE DRY CONDITIONS...PRESSURE RISES ALONG THE COAST
AND FALLS WITH THE THERMAL TROUGH OVER THE INTERIOR IS INCREASING
SOUTHERLY WINDS ACROSS THE BASIN THIS EVENING.

&&

.MODEL DISCUSSION (SHORT TERM)...
THE MODELS ARE REASONABLE AND IN FAIRLY GOOD AGREEMENT WITH THE
SURFACE/UPPER LEVEL FEATURES AS WELL AS THE PRECIPITATION PATTERN
THROUGH MONDAY. ALL CONTINUE TO TO SHOW A WEAKENING OF THE GULF
HIGH AND AN INCREASE IN COOL AND MOIST SOUTHERLY FLOW MOVING INTO
SOUTH CENTRAL. OUT WEST...MODELS AGREE ON THE WEAKENING AND
LIFTING NORTH OF THE CURRENT BERING SEA LOW (OLD TYPHOON DOLPHIN)
AND THE STRENGTHENING OF A NEW CENTER MOVING SOUTH OF KAMCHATKA
TONIGHT AND INTO THE BERING SEA SUN NIGHT/MON. OVERALL FORECAST
CONFIDENCE REMAINS ABOVE AVERAGE THROUGH MONDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

A MOIST AND STABLE AIR MASS CONTINUES TO PUSH NORTH AND EAST
ACROSS SOUTHCENTRAL ALASKA. LIGHT RAIN WILL CONTINUE AND/OR
DEVELOP THROUGH THE OVERNIGHT HOURS ESPECIALLY ACROSS MUCH OF THE
KENAI PENINSULA...ANCHORAGE...AND THE MAT-SU VALLEY. THESE
CONDITIONS WILL GRADUALLY IMPROVE SUNDAY ESPECIALLY FROM ANCHORAGE
SOUTH BEFORE LIGHT RAIN IS LIKELY TO DEVELOP AGAIN OVERNIGHT
SUNDAY NIGHT TOWARD ANCHORAGE AT LEAST FOR A BRIEF TIME. BY
MONDAY...A BIT MORE INSTABILITY WILL OVERSPREAD THE REGION AND
WITH PLENTIFUL MOISTURE PRESENT WILL RESULT IN WIDESPREAD
SCATTERED TO NUMEROUS RAIN SHOWERS ACROSS THE SOUTHCENTRAL
MAINLAND FOR MEMORIAL DAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

LOW PRESSURE ACROSS THE WESTERN BERING PUSHES A FRONT INTO THE
SOUTHWEST MAINLAND TONIGHT. GUSTY SOUTHEASTERLY FLOW ALONG THE
BOUNDARY WILL TAPER OFF AFTER MIDNIGHT. NUMEROUS PREFRONTAL RAIN
SHOWERS ALONG THE WEST COAST WILL SPREAD EAST OVERNIGHT AS THE
MAIN FRONT MOVES INLAND. ON SUNDAY...THE FRONT STALLS ACROSS THE
REGION AND WEAKENS THROUGH MONDAY. SCATTERED RAIN SHOWERS CONTINUE
INTO THE BEGINNING OF THE WEEK AS ANOTHER UPPER LEVEL LOW DEVELOPING
NEAR KODIAK MOVES A SHORTWAVE INTO BRISTOL BAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE STACKED LOW PRESSURE SYSTEM ACROSS THE BERING SLOWLY MOVES A
FRONT FROM THE EASTERN BERING INTO THE SOUTHWEST MAINLAND
TONIGHT. BEHIND THIS SYSTEM...A SHORTWAVE QUICKLY MOVES ACROSS THE
WESTERN BERING TONIGHT AND MERGES WITH THE MAIN UPPER LOW. GUSTY
GRADIENT WINDS ARE EXPECTED TO INCREASE ACROSS THE WESTERN HALF OF
THE ALEUTIANS THIS EVENING AND THEN TAPER OFF ON SUNDAY AS THE
MAIN LOW MOVES INTO THE NORTHERN BERING. THE NEXT STRONG LOW
DEVELOPS SUNDAY NIGHT MOVING INTO THE WESTERN BERING EARLY MONDAY.
THIS SYSTEM SPINS IN PLACE ON MONDAY SENDING ANOTHER FRONT TOWARD
THE CENTRAL BERING.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

MODELS REMAIN IN AGREEMENT THAT A RIDGE OF VARYING STRENGTH WILL
PERSIST OVER MUCH OF THE EASTERN AK MAINLAND THROUGH NEXT WEEK.
SOUTHERLY FLOW ALONG THE WESTERN FLANK OF THE HIGH WILL BRING
RAIN TO THE NORTH GULF COAST AND SOME INLAND SHOWERS THROUGH TUE.
AS THE RIDGE INCREASES IN STRENGTH IT WILL CUT OFF THE ONSHORE
FLOW AND PRECIPITATION TUE NIGHT THROUGH THU. A SLIGHT WEAKENING
OF THE RIDGE WILL AGAIN ALLOW ONSHORE FLOW TO BRING RAIN TO THE
COAST AND SHOWERS TO INLAND AREAS AT THE END OF THE WEEK.

A BROAD AREA OF LOW PRESSURE WILL PERSIST OVER THE BERING. THIS
WILL KEEP RAIN AND SHOWERS OVER THE ALEUTIANS AND SW AK THROUGH
NEXT WEEK...ENHANCED AT THE END OF THE WEEK AS A LOW AND
ASSOCIATED FRONT MOVE JUST SOUTH OF THE CHAIN.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 173 175 176 177 178 180 181.
FIRE WEATHER...RED FLAG WARNING 141.

&&

SYNOPSIS AND MODEL DISCUSSION...BC
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DS