Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 282141
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
141 PM AKDT MON JUL 28 2014

.ANALYSIS AND UPPER LEVELS...
THE MAIN PATTERN CONSISTS OF AN UPPER LEVEL RIDGE OVER THE
CENTRAL/EASTERN BERING SEA AND A TROUGH OVER MAINLAND ALASKA AND
THE GULF. THERE IS ANOTHER TROUGH WEST OF OF THE RIDGE OVER THE
WESTERN BERING AND KAMCHATKA PENINSULA. WITHIN THE MAINLAND TROUGH
THERE IS AN UPPER LEVEL LOW OVER SOUTHERN ALASKA RAPIDLY MOVING
SOUTH.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH 84 HOURS WITH
JUST A FEW DIFFERENCES IN MINOR DETAILS. AS A RESULT OF THIS...THE
FORECAST CONFIDENCE IS ABOVE NORMAL FOR THE AFTERNOON PACKAGE.

&&

.SHORT TERM FORECAST...

FOR SOUTH CENTRAL ALASKA...THE UPPER LOW OVER THE AREA WILL
RAPIDLY PUSH INTO THE GULF OF ALASKA THROUGH TUESDAY MORNING.
DECENT RATES OF PRECIPITATION ARE EXPECTED FROM THE
MATANUSKA/SUSITNA VALLEYS THROUGH THE COOK INLET AREA TONIGHT.
TOTAL RAINFALL AMOUNTS WILL BE LIMITED DUE TO THE FAST MOVEMENT
OF THE LOW. ON TUESDAY THE BERING RIDGE WILL ASSERT ITSELF INTO
THE AREA AND DRY CONDITIONS AREA EXPECTED THROUGH THURSDAY. SOME
"WRAP AROUND" MOISTURE FROM THE GULF LOW WILL PUSH INTO THE COPPER
RIVER BASIN AND EASTERN PRINCE WILLIAM SOUND AREA TUESDAY AND
TUESDAY NIGHT FOR SOME SHOWERS/RAIN...THEN ON WEDNESDAY THE RIDGE
WILL PUSH EAST INTO THOSE AREAS AS WELL.

FOR SOUTHWEST ALASKA...SHOWERS WILL CONTINUE TONIGHT THEN TAPER
OFF ON TUESDAY AS THE UPPER LOW OVER THE AREA PUSHES TO THE
SOUTH...ENDING BY TUESDAY EVENING. THEN THE EASTERN BERING RIDGE
WILL BUILD STRONGLY OVER THE AREA THROUGH THURSDAY...KEEPING
CONDITIONS DRY.

FOR THE BERING SEA/ALEUTIANS...THE UPPER LEVEL RIDGE WILL HOLD
OVER THE CENTRAL/EASTERN BERING/ALEUTIANS THROUGH THURSDAY. A
SERIES OF FRONTS ASSOCIATED WITH THE KAMCHATKA/WESTERN BERING LOW
WILL PUSH UP THE WEST SIDE OF THE RIDGE THROUGH THURSDAY...WITH
PRECIPITATION AND SOUTHEASTERLY WINDS POSSIBLY PUSHING AS FAR EAST
AS ATKA.

&&

.LONG TERM FORECAST...
OMEGA BLOCKING CENTERED OVER THE NORTHERN BERING SEA WILL
CONTINUE TO DRIVE THE SENSIBLE WEATHER ACROSS MOST OF ALASKA
REGION ON FRIDAY. MUCH OF SOUTHERN ALASKA WILL REMAIN UNDER THE
INFLUENCE OF WEAK SHORTWAVE RIDGING...WHICH WILL KEEP MOST OF THE
AREA SLIGHTLY WARMER THAN AVERAGE...WITH SHOWERS RELEGATED TO THE
MOUNTAINS. SOUTHWEST ALASKA WILL REMAIN ALONG THE PERIPHERY OF THE
BLOCKING HIGH OVER THE BERING AND TROUGHING ACROSS THE NORTH
SLOPE...WITH RAIN AND SHOWER THREATS ALONG THE QUASISTATIONARY
FRONT. RIDGING WILL REMAIN PERSISTENT ACROSS THE BERING THROUGH
THE WEEKEND...BUT UNCERTAINTY ARISES ACROSS SOUTHERN ALASKA BY
SUNDAY. THE ECMWF CONTINUES TO HINT AT NORTHERN STREAM ENERGY
DIVING INTO THE GULF AND INTERACTING WITH THE CURRENT CLOSED
LOW...WHILE THE CANADIAN GDPS AND GFS BUILD THE BERING RIDGE INTO
SOUTHERN ALASKA. THE CURRENT FORECAST WILL TAKE A MIDDLE GROUND
APPROACH...HIGHLIGHTING THE POTENTIAL FOR INCREASING PRECIPITATION
CHANCES BY SUNDAY AND MONDAY...AND NEAR CLIMATOLOGICAL
TEMPERATURES.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.
&&

$$

LUDWIG/JA JUL 14


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