Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 131400
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
600 AM AKDT SAT SEP 13 2014

.ANALYSIS AND UPPER LEVELS...
THE NEGATIVE TILTED RIDGE REMAINS OVER SOUTHEAST ALASKA EXTENDING
TO THE NORTHWEST THROUGH BARROW. SATELLITE IMAGERY SHOWS THE
STRONG CLOSED UPPER LEVEL LOW SOUTHWEST OF SAINT GEORGE. THE UPPER
LOW IS STACKED WITH A 963 MB LOW CENTER. A SWATH OF RAIN IS
WRAPPED AROUND THE OCCLUDED LOW. THE SURFACE OBSERVATIONS ALONG
THE CENTRAL ALEUTIANS ARE REPORTING STRONG WESTERLY WINDS WITH
GUSTS TO 50 TO 60 MPH RANGE THIS MORNING. TO THE EAST OF THE MAIN
LOW A FRONT PUSHED THROUGH THE NORTHERN GULF OF ALASKA BRINGING HEAVY
PRECIPITATION ALONG THE EASTERN KENAI PENINSULA...PRINCE WILLIAM
SOUND AND NORTHEASTERN GULF COAST. GUSTY WINDS CONTINUE THROUGH
CHANNELED TERRAIN AND HAVE DIMINISHED UNDER HIGH WIND CRITERIA FOR
THE TURNAGIAN ARM AND HIGHER ELEVATIONS.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT WITH THE OCCLUDED LOW IN THE
CENTRAL BERING SEA. THE ECMWF/NAM VERIFIED WELL WITH THE 12Z
SURFACE POSITION AND STRENGTH OF THE STORM. THIS STORM IS
PROJECTED TO MOVE INTO THE BRISTOL BAY BY SUNDAY. THE ECMWF HAS
THE LOW MOVING INLAND NEAR DILLINGHAM EARLY MONDAY MORNING AND THE
GFS IS TRACKING THE LOW FARTHER NORTH THROUGH THE KUSKOKWIM DELTA.
THE MODELS HAVE A FRONTAL BOUNDARY MOVING THROUGH THE NORTHERN
GULF THIS MORNING BEFORE MOVING INLAND AND FALLING APART OVER THE
WEEKEND. THE NAM IS HANDLING THE QPF BETTER THAN THE OTHER MODELS.
THE NAM WAS THE PREFERRED MODEL FOR THE SOUTHCENTRAL ALASKA/GULF
AND THE ECMWF/NAM MODELS FOR THE SOUTHWEST ALASKA/BERING SEA
REGION. THE FORECAST CONFIDENCE IS GOOD FOR THE WEEKEND.

&&

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
THE FRONTAL BOUNDARY WILL PUSH THROUGH THE NORTHERN GULF THIS
MORNING BEFORE MOVING INLAND AND DISSIPATING. THIS WILL BRING THE
HEAVIEST RAINFALL OVER THE EASTERN KENAI PENINSULA AND NORTHERN
GULF COASTLINE. THE PRECIPITATION WILL TAPER OFF AS THE FRONT
MOVES THROUGH THE REGION TODAY. THE FLOOD ADVISORY REMAINS IN
EFFECT FOR THE EASTERN KENAI PENINSULA UNTIL 3 PM AKDT TODAY FOR
SMALL STREAMS...RIVERS IN AND AROUND SEWARD. UP TO THREE INCHES
OF RAIN HAVE ALREADY FALLEN WITH ADDITIONAL RAINFALL UP TO TWO
INCHES IS EXPECTED OVER THE AREA THROUGH THIS AFTERNOON. THE
RESURRECTION RIVER AT EXIT GLACIER BRIDGE IS AT MINOR FLOOD STAGE
THIS MORNING. THE HIGH WIND WARNING IS CANCELLED FOR THE TURNAGAIN
ARM AND HIGHER ELEVATIONS WITH THE GRADIENT WEAKENING THIS MORNING.


SOUTHWEST ALASKA...
THE OCCLUDED LOW NEAR THE PRIBILOF ISLANDS WILL TRACK TOWARDS
BRISTOL BAY BY SATURDAY EVENING BRINGING GUSTY GALE FORCE WINDS
ALONG THE SOUTHWEST ALASKA COASTLINE FOR THE WEEKEND. THIS WILL
BRING MORE WIDESPREAD CLOUDS AND RAIN TO THE REGION THROUGH THE
EARLY PART OF NEXT WEEK WITH THE OCCLUDED LOW TRACKING INLAND
NEAR DILLINGHAM BY SUNDAY.

BERING SEA/ALEUTIANS...
THE OCCLUDED LOW IN THE CENTRAL BERING SEA WILL DROP FARTHER SOUTH
OF THE PRIBILOF ISLAND BRINGING STRONG GUSTY WINDS TO THE CENTRAL
ALEUTIANS. THE HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 AM
AKDT THIS MORNING FOR THE CENTRAL ALEUTIANS INCLUDING ATKA AND
ADAK. THE WINDS WILL DIMINISH GRADUALLY AS THE LOW MOVES EASTWARD
TOWARDS BRISTOL BAY. THIS STORM IS BRINGING STORM/GALE FORCE WINDS
TO THE MAJORITY OF THE BERING SEA WITH SHOWERY PRECIPITATION.

&&

.LONG TERM FORECAST...
MODELS HAVE COME INTO BETTER AGREEMENT OVER THE PAST 24 HOURS ON
THE EVOLUTION OF THE BERING LOW BY EARLY NEXT WEEK...WITH THE GFS
FINALLY FALLING IN LINE WITH THE EC SOLUTION IN BRINGING THE LOW
TOWARDS BRISTOL BAY. THE MODELS ARE IN SLIGHT DISAGREEMENT WITH
LOCATION OF LOW WHEN IT MOVES ONSHORE. THE ECMWF MODEL TRACKS THE
LOW INLAND NEAR DILLINGHAM. THE GFS TAKES THE LOW INLAND NEAR
KUSKOKWIM DELTA ON MONDAY. THE END RESULT WILL BE A CONTINUATION
OF THE WET PATTERN ACROSS THE SOUTHCENTRAL ALASKA REGION WITH
MOIST SOUTHERLY ONSHORE FLOW. MEANWHILE...A SHOWERY PATTERN WILL
PREVAIL OVER MUCH OF THE BERING BENEATH THE BROAD UPPER TROUGH.

AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING 187.
         FLOOD ADVISORY 125.
MARINE...GALE 119 125 150 155 160 165 171 177 179 180 411 412 414.
         STORM 170 172 173 174 175 176 413.
FIRE WEATHER...NONE.

&&

$$

PLD/CB SEP 14



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