Gale Warning 450, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
130 PM AKDT SUN JUN 30 2013

.ANALYSIS AND UPPER LEVELS...
THE LAST VESTIGES OF THE PERSISTENT HIGH PRESSURE ARE CONFINED TO THE
FAR EASTERN INTERIOR...AS MOST OF THE MAINLAND HAS NOW COME UNDER THE
INFLUENCE OF A LARGE VERTICALLY-STACKED LOW IN THE CENTRAL BERING
SEA. COPIOUS LOW-LEVEL MOISTURE TRAPPED AROUND COOK INLET AND PRINCE
WILLIAM SOUND IS NOW BEGINNING TO EXPERIENCE MOIST SOUTHWEST FLOW
AHEAD OF THE FRONT...THUS WILL NOT SEE MUCH IN THE WAY OF CLEARING
SKIES TODAY BEFORE RAIN MOVES IN TOMORROW. OUT WEST...THE INITIAL
WEATHER FRONT THAT BROUGHT RAIN TO THE SOUTHWEST MAINLAND COAST HAS
WEAKENED AND PUSHED INLAND. FURTHER WEST...A ROBUST 160 KT JET STREAK
SUPPORTING THE UPPER LOW HAS HELPED TO FORM A SECONDARY FRONT IN THE
EASTERN BERING SEA THAT IS PREPARING TO MOVE INLAND AND BRING ANOTHER
ROUND OF RAIN AND WIND TO THE MAINLAND. THIS FRONT WILL REMAIN INTACT
LONGER AND WILL BE A KEY PLAYER IN THE WEATHER OVER THE NEXT 36 HOURS
ACROSS SOUTH CENTRAL PORTIONS OF THE STATE IN ADDITION TO THE
SOUTHWEST COAST.

.MODEL DISCUSSION...
MODELS REMAIN IN ABOVE AVERAGE OVERALL AGREEMENT. THE UPPER LOW
MOVING INTO THE NORTHERN BERING SEA WILL STALL AS THE LONGWAVE TROUGH
BECOMES MORE ESTABLISHED OVERNIGHT. THIS WILL RESULT IN A
STEADY-STATE PATTERN FOR THE SHORT-TERM FORECAST PERIOD THAT FEATURES
BROAD SOUTHWEST FLOW ACROSS MUCH OF THE STATE...WITH NUMEROUS
EMBEDDED SHORTWAVE TROUGHS PINWHEELING AROUND THE PARENT LOW. THIS
SETS THE STAGE FOR MOST OF SOUTHERN ALASKA TO EXPERIENCE CLOUDY
CONDITIONS AND PERIODS OF RAIN THROUGH AT LEAST THE MIDDLE OF THE
WEEK.

.SHORT TERM FORECAST...
SOUTHCENTRAL...WINDS ARE ALREADY INCREASING THROUGH TURNAGAIN ARM AS
THE PRESSURE GRADIENT ACROSS THE AREA BEGINS TO TIGHTEN. RAIN
ASSOCIATED WITH THE FRONT IS IN THE PROCESS OF OVERTAKING KODIAK
ISLAND...AND WILL MOVE UP THE KENAI PENINSULA OVERNIGHT BEFORE
REACHING ANCHORAGE AND THE MAT-SU MONDAY MORNING. A GENERALLY
NORTH-SOUTH ORIENTATION TO THE FRONT WILL BE FAVORABLE FOR WINDS IN
TURNAGAIN ARM TO CURVE INTO SOUTH AND WEST ANCHORAGE TONIGHT INTO
TOMORROW MORNING. ALL MODELS SUGGEST A PERIOD DURING THE DAY MONDAY
WHEN A WEAK SURFACE LOW WILL FORM NEAR LOWER COOK INLET AND MOVE
NORTHWARD. THIS SHOULD RE-ORIENT THE PRESSURE GRADIENT ENOUGH TO END
THE SOUTHERLY WINDS IN ANCHORAGE BRIEFLY...BEFORE RESUMING LATE
MONDAY AFTERNOON AS THE AFOREMENTIONED LOW MOVES OFF TO THE NORTH.
THIS SAME SMALL FEATURE WILL LIKELY ALSO ENABLE A BIT OF DOWNSLOPE
DRYING IN THE USUAL AREAS (WESTERN KENAI UP THROUGH ANCHORAGE TO THE
MATANUSKA VALLEY) ON MONDAY BEFORE SOUTHWEST FLOW AGAIN RESUMES WITH
MORE SHOWERY PRECIPITATION MONDAY EVENING. FURTHER EAST...THE FRONT
CRAWLING EASTWARD WILL DEVELOP A FAIRLY WEAK RIDGE OF HIGH PRESSURE
ALONG THE COASTAL MOUNTAINS. THIS WILL BRING GUSTY WINDS INTO PARTS
OF THE COPPER RIVER BASIN THROUGH MONDAY EVENING...THUS HAVE EXTENDED
THE THREAT FOR DANGEROUS FIRE WEATHER CONDITIONS THROUGH TOMORROW.

SOUTHWEST MAINLAND...A SECOND ROUND OF WIDESPREAD RAIN IS JUST NOW
PUSHING ONSHORE THE DELTA COAST. THIS WILL BRING WIDESPREAD RAIN TO
VIRTUALLY ALL PARTS OF THE REGION. AS THE UPPER LOW BECOMES
STATIONARY OVER THE NORTHERN BERING SEA BY TOMORROW...SOUTHWEST FLOW
WITH NUMEROUS EMBEDDED SHORTWAVES WILL BRING ROUNDS OF GUSTY
SOUTHERLY WIND AND RAIN TO BOTH THE COASTLINES AND LOCATIONS INLAND
THROUGH WEDNESDAY.

BERING SEA AND ALEUTIANS...WITH THE FRONT MOVING INTO THE MAINLAND
MOST OF THE AREA IS NOW EXPERIENCING WINDS OUT OF THE SOUTHWEST WITH
SCATTERED TO NUMEROUS RAIN SHOWERS. THE STRONGEST WINDS ARE ON THE
SOUTH SIDE OF THE LOW PRESSURE CENTER ITSELF...CURRENTLY AFFECTING
THE CENTRAL ALEUTIANS AND SOUTHERN BERING SEA. WINDS WILL DIMINISH
THROUGH MIDWEEK...BUT COOLER THAN NORMAL TEMPERATURES AND RAIN
SHOWERS WILL CONTINUE ACROSS THE AREA.

.LONG TERM FORECAST...
A STRONG BLOCKING RIDGE OVER THE WEST COAST OF NORTH AMERICA WILL
REMAIN PLACE THROUGH AT LEAST NEXT WEEKEND. FOR ALASKA...THIS MEANS
THE LONGWAVE TROUGH OVER THE BERING SEA WILL REMAIN IN PLACE DURING
THE SAME PERIOD. THUS EXPECT COOL AND CLOUDY CONDITIONS ACROSS MOST
PARTS OF THE STATE TO CONTINUE THROUGHOUT THE COMING WEEK...WITH
MULTIPLE CHANCES FOR RAIN AT VIRTUALLY ALL LOCATIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 130 170 172 179
FIRE WEATHER...RED FLAG WARNING 141

DIXON JUN 13