Area Forecast Discussion - SouthCentral and SouthWest


FXAK68 PAFC 010320
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
720 PM AKDT THU JUL 31 2014
.ANALYSIS AND UPPER LEVELS...
AN OMEGA BLOCK REMAINS OVER THE AREA. THE UPPER LEVEL HIGH IS
CENTERED OVER THE NORTHERN BERING SEA WITH AN UPPER LOW CENTERED
JUST TO THE WEST OF THE WESTERN ALEUTIANS AND ANOTHER LOW OVER
CENTERED OVER THE SOUTHWEST GULF OF ALASKA. A WEAK WEATHER SYSTEM
IS "ROUNDING" THE HIGH AND PUSHING MOISTURE (SLOWLY) INTO
SOUTHWEST ALASKA FROM THE NORTHWEST.

&&
.MODEL DISCUSSION...
FORECAST CONFIDENCE WITH THE AFTERNOON PACKAGE IS HIGHER
THAN NORMAL. THE NUMERICAL MODELS ARE ONCE AGAIN IN GOOD
AGREEMENT AS A STABLE BLOCKING PATTERN MAKES THEIR JOB EASIER.
SOME DISCREPANCIES BEGIN TO SHOW UP ON SUNDAY AS THE BLOCK LOOKS
LIKE IT WILL BEGIN TO WEAKEN. 

&&
.SHORT TERM FORECAST...

FOR SOUTH CENTRAL ALASKA...THE BLOCKING PATTERN WILL FOR THE MOST
PART KEEP SOUTHERN ALASKA DRY THROUGH SATURDAY. ONE EXCEPTION IS
SOME DIURNAL SHOWERS OVER THE MOUNTAINS...THOUGH THESE SHOULD BE
QUITE LIMITED WITH THE UPPER RIDGE OVERHEAD. ANOTHER EXCEPTION IS
THE SUSITNA VALLEY AREA AS SOME MOISTURE PUSHES AROUND THE HIGH
INTO THAT AREA FROM THE NORTHWEST LATER FRIDAY INTO SATURDAY. THIS
WILL THEN RETREAT NORTHWARD ON SUNDAY. 

LATE SATURDAY SUNDAY THE GULF LOW WILL BEGIN TO PUSH NORTHWARD.
THIS WILL BRING A (RATHER WEAK) WEATHER FRONT WITH IT.
PRECIPITATION FROM THIS FRONT WILL LIKELY REACH KODIAK ISLAND LATE
SATURDAY...PUSHING INTO THE GULF COAST SUNDAY MORNING...AND
POSSIBLY INTO INLAND AREAS LATER SUNDAY.

FOR SOUTHWEST ALASKA...MOISTURE IS SLIDING OVER THE RIDGE INTO THE
AREA FROM THE NORTHWEST. EASTWARD PROGRESSION OF PRECIPITATION
WILL STALL PROBABLY JUST WEST OF DILLINGHAM...AND SOUTH OF NUSHAGAK
HILLS. THUS THE WEATHER WILL BE DIVIDED FOR THE NEXT FEW DAYS WITH
SHOWERS OVER THE NORTHWEST PORTION OF THE AREA AND DRY CONDITIONS
IN THE BRISTOL BAY AREA. ON SUNDAY AS THE GULF LOW MOVES NORTH THE
SYSTEM OVER THE NORTHWEST PORTION OF THE AREA WILL DISSIPATE...BUT
MOISTURE MOVING UP FROM THE SOUTH WILL BEGIN TO PUSH INTO
SOUTHWEST ALASKA.

FOR THE BERING SEA/ALEUTIANS...HIGH PRESSURE WILL REMAIN OVER THE
BERING SEA THROUGH SUNDAY...SLOWLY MOVING TO THE NORTHWEST THROUGH
SATURDAY THEN BEGINNING TO WEAKEN AND SHRINK IN SIZE ON SUNDAY.
THE UPPER LOW TO THE WEST OF THE ALEUTIANS WILL SLOWLY DRIFT
NORTH AND WEAKEN THROUGH SATURDAY THEN BE EJECTED NORTHWARD ON
SUNDAY BY ANOTHER UPPER LOW PUSHING OUT OF SIBERIA.

&&
.LONG TERM FORECAST...

THE OMEGA BLOCKING OVER THE BERING SEA WILL CONTINUE TO RETROGRADE 
TO THE SOUTH THROUGH THE EARLY PART OF NEXT WEEK. STRATUS AND FOG
WILL PERSIST WITH LIGHT WINDS THROUGH MONDAY. AN UPPER LEVEL WEAK
SHORTWAVE TROUGH WILL DROP DOWN FROM THE UPPER KUSKOKWIM VALLEY
INTO THE SOUTHWEST ALASKA REGION BY MONDAY. THIS WILL BRING
INCREASED CLOUDS AND SHOWERS THROUGHOUT THE AREA. AN UPPER LEVEL
LOW WILL START TO ENTER THE SOUTHWESTERN GULF OF ALASKA BY
MONDAY. AN INVERTED TROUGH ASSOCIATED WITH THIS LOW WILL EXTEND
THROUGH THE ALASKA PENINSULA AND THROUGH THE ALASKA RANGE. THIS
WILL BRING NORTHEASTERLY WINDS AND INCREASED CLOUD COVER WITH RAIN
ALONG THE COASTLINE AND SPREADING INLAND THROUGH THE EARLY PART OF
NEXT WEEK.


&&

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

$$

LUDWIG/PD JUL 14