292 
FXAK68 PAFC 041245
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKDT FRI OCT 4 2013

.ANALYSIS AND UPPER LEVELS...
PRESSURES AT THE CENTER OF THE WESTERN GULF SURFACE LOW CONTINUE TO
LEVEL AS DYNAMIC SUPPORT HAS ONCE AGAIN RUN OUT. THE UPPER TROUGH
EASES SLOWLY EASTWARD IN THE GULF WITH THE REMAINING SURFACE LOW
AMALGAMATING INTO A BROAD COMPLEX CENTER UNDER THE UPPER LOW. WIND
SPEEDS IN THE JET STREAK DOWNSTREAM OF THE LONG-WAVE APPROACH 140 KT.
ENTERING THE BACKSIDE OF THE TROUGH...A WEAKER JET STREAK CONTINUES
PUSHING THE PROGRESSIVE PATTERN. RAIN SHOWERS PERSIST IN THE GULF...
ALTHOUGH THE FRONT IS RAPIDLY WEAKENING EARLY THIS MORNING.
YESTERDAY'S COASTAL JET HAS WOUND DOWN WITH THE ENERGY SHIFTING
UNDERNEATH THE BACKSIDE JET BEHIND THE LOW BRINGING THE STRONGEST
SUSTAINED WINDS FROM BRISTOL BAY THROUGH THE SOUTHERN GULF. 

FURTHER OUT WEST...A MUCH DEEPER SYSTEM APPROACHES THE WESTERN BERING
SEA OVER KAMCHATKA AND LOOKS TO BE THE NEXT FOCUS FOR ACTIVE WEATHER
OVER THE GREAT LAND. 
 
.MODEL DISCUSSION...
GUIDANCE IN GOOD AGREEMENT WITH THE CURRENT LOW BECOMING COMPLEX IN
THE GULF AND SLOWLY WEAKENING TODAY. THE AGREEMENT REMAINS THROUGH
THE WEEK AS A LARGE KAMCHATKA LOW SWINGS A FRONT OVER THE BERING SEA
ONTO THE MAINLAND BY LATE FRIDAY NIGHT/EARLY SATURDAY MORNING. THE
UPPER TROUGH SHIFTING OVER THE BERING SEA LOOKS TO CONTROL THE ACTIVE
WEATHER PATTERN INTO EARLY NEXT WITH SEVERAL EMBEDDED DISTURBANCES
PROPAGATING THROUGH THE SOUTHWESTERLY FLOW ALOFT.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...SHOWERS IN THE GULF SHOULD CONTINUE TO TAPER
AND SHIFT SOUTH AS THE SURFACE LOW WEAKENS FLOW TRANSITIONS TO A
DRIER OFFSHORE SETUP. CLOUDS WILL BE ON THE DECREASE TODAY AS THE
GULF LOW WEAKENS AND PULLS AWAY. THE WEEKEND WILL SEE MOSTLY DRY
CONDITIONS WITH SEASONABLE TEMPERATURES WITH THE AREA BETWEEN
SYSTEMS. A FRONTAL BOUNDARY WILL PUSH IN FROM THE WEST ON SUNDAY
RETURNING THE CHANCES FOR PRECIPITATION AND USHERING A PERIOD OF
ACTIVE WEATHER.

SOUTHWEST ALASKA...GUSTY NORTHERLY FLOW CONTINUES ON THE BACKSIDE OF
THE DEPARTING LOW PRESSURE. WINDS WILL SLOWLY TAPER TODAY AS THE
SYSTEM MOVES EAST IN THE GULF AND HIGH PRESSURE SLIDES IN AHEAD OF AN
APPROACHING FRONT WHICH WILL BRING GUSTY SOUTHERLY WINDS AND RAIN
BEGINNING EARLY SATURDAY MORNING AND MOVING INTO THE MAINLAND THROUGH
SUNDAY. 

BERING SEA AND ALEUTIANS...GUSTY NORTHERLY WINDS AND SHOWERS OVER THE
EASTERN ALEUTIANS AND ALASKA PENINSULA WILL TAPER OFF TODAY AS HIGH
PRESSURE BUILDS ACROSS THE REGION. A WARM/COLD FRONT COMBO WILL CROSS
THE BERING SEA TODAY RAMPING UP WINDS FROM THE SOUTH AHEAD OF THE
FRONT FOLLOWED BY A THREE TO SIX HOUR PERIOD OF RAIN WITH WINDS
SHIFTING TO THE WEST BEHIND THE COLD FRONT. GUSTY WESTERLY WINDS WILL
CONTINUE THROUGH THE WEEKEND.  

.LONG TERM FORECAST...
THE EXTENDED FORECAST WILL BE SHAPED BY THE UPPER LOW ENTERING THE
BERING SEA. A SIGNIFICANT BASAL SHORTWAVE WILL APPROACH THE ALASKA
PENINSULA EARLY NEXT WEEK ALONG WITH A SIGNIFICANT SLUG OF MOISTURE
WHICH WILL OVERSPREAD MUCH OF THE SOUTHCENTRAL AS WELL AS BRING
ANOTHER SHOT OF WINDS TO THE COAST AND CHANNELED TERRAIN AREAS. THE
PLANETARY LONG-WAVE NUMBER REMAINS HIGH...THEN TREND OF LOW TO
MODERATE AMPLITUDE WAVES IN A FAST ZONAL FLOW WILL KEEP THE
PROGRESSIVE PATTERN ROLLING. 


.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 170 172 173 174 175 176 177 178 179 180 181 185
FIRE WEATHER...NONE

MTL OCT 13