000 FXAK68 PAFC 241429 AFDAFC AREA FORECAST DISCUSSION SOUTHCENTRAL AND SOUTHWEST ALASKA 500 AM AKST TUE NOV 24 2009 .ANALYSIS AND UPPER LEVELS... IN THE UPPER-LVLS A TROF IS DRAPED THROUGH THE EASTERN BERING AND SW AK...WITH TRANSITORY RIDGING OVER THE CENTRAL ALEUTIANS AND WEAK RIDGING BACK THROUGH SE AK AND THE E COPPER RIVER BASIN. AN UPPER-LOW IS CENTERED OVER THE N CENTRAL BERING...AND THE NORTH CENTRAL PACIFIC. AT THE SURFACE A STORM-FORCE LOW IS NEARING THE FAR WESTERN ALEUTIANS AND BERING AS IT MOVES EAST. A WEAK SURFACE LOW IS MOVING PAST THE PRIBILOFS AND DISSIPATING AS IT APPROACHES THE KUSKOKWIM DELTA COAST. FINALLY A DEEP LOW IS MOVING NORTH TOWARDS THE GULF OF AK. .MODEL DISCUSSION... MODELS SATISFACTORILY CAPTURE THE SURFACE FEATURES ACROSS THE AOR THROUGH THURSDAY. THE MORNING PACKAGE LEANED ON THE GFS SOLUTION BASED ON ACCEPTABLE INITIALIZATION AND CONTINUITY. THE LOW OVER THE NORTH CENTRAL PACIFIC WILL ADVANCE NORTH INTO THE CENTRAL GULF WEDNESDAY...WITH A SECONDARY AREA OF LOW PRESSURE DEVELOPING OVER THE FAR NORTHERN GULF NEAR MIDDLETON ISLAND EARLY WEDNESDAY MORNING. MODELS ADEQUATELY HANDLE THE LOW PRESSURE SYSTEM APPROACHING THE WESTERN ALEUTIANS AS IT MOVES THROUGH THE SOUTHERN BERING...BUT DIFFERENCES ARISE REGARDING THE FORMATION AND SUBSEQUENT MOVEMENT OF A TRIPLE POINT LOW ON THURSDAY MORNING OFF THE SOUTHERN AKPEN. THE NAM APPEARS THE OUTLIER WITH ROTATING THIS FEATURE SOUTH OF KODIAK INTO THE HEART OF THE GULF...WITH OTHER SOLUTIONS CLUSTERED FURTHER WEST UP THE S AKPEN INTO BRISTOL BAY. LONG-RANGE...THE GFS/EC ARE RATHER SIMILAR IN CAPTURING THE PATTERN....WHEREAS IN THE WEST THERE ARE LARGER DIFFERENCES. LONG-RANGE FORECASTS TREND TOWARDS THE EC. .SHORT TERM FORECAST... .SOUTHCENTRAL... RAIN/SNOW SHOWERS CONTINUE IN THE SOUTHERLY FLOW OVER PRINCE WILLIAM SOUND...THOUGH DRYING OUT OVER THE SOUTHERN MAINLAND...AS THE REMNANT FRONT WASHES OUT OVER THE SUSITNA VALLEY TUESDAY. STEADIER PRECIPITATION IN STORE FOR SOUTHCENTRAL ON WEDNESDAY AS THE NEXT LOW ROTATES UP THE GULF...PARTICULARLY OVER THE KENAI PENINSULA AND KODIAK ISLAND. STRONG NORTH TO WEST WINDS ALONG THE WESTERN PERIPHERY OF THE LOW WILL SUPPORT BLOWING SNOW ALONG WITH FALLING SNOW FOR KODIAK TUESDAY NIGHT INTO EARLY WEDNESDAY. THE SECONDARY AREA OF LOW PRESSURE PROGGED TO DEVELOP OVER THE NORTHERN GULF COUPLED WITH A SHORTWAVE THAT WILL APPROACH FROM THE ALEUTIAN RANGE LOOKS TO SET UP A DEFORMATION ZONE OF MOISTURE THAT MAY SQUEEZE OUT PERIODS OF SNOW OVER THE ANCHORAGE BOWL AND MAT-SU VALLEYS ON WEDNESDAY AS WELL. REMNANTS OF THIS SYSTEM MOVE ASHORE WEDNESDAY NIGHT...WITH ANY PRECIPITATION TAPERING TO SNOW SHOWERS. MOISTURE FROM TRIPLE POINT LOW DEVELOPING NEAR THE S AKPEN LOOKS TO BRING ANOTHER ROUND OF RAIN/SNOW INTO THE KENAI PENINSULA AND KODIAK FOR THURSDAY. .SOUTHWEST... PERIODS OF SNOW SHOWERS THROUGH THE KUSKOKWIM VALLEY/DELTA AND BRISTOL BAY AS SHORTWAVES ROTATE THROUGH THE UPPER-LVL FLOW. STEADIER SNOW IN STORE AS THE BERING LOW AND ASSOCIATED TRIPLE POINT SPREAD DEEPER MOISTURE INTO THE SW MAINLAND ON THURSDAY. .BERING SEA/ALEUTIANS... ENHANCED SNOW SHOWER ACTIVITY FOR THE PRIBILOFS AS WAVE OF LOW PRESSURE MOVES THROUGH. OTHERWISE STEADIER RAIN AND SNOW FOR THE ALEUTIAN ISLANDS AS THE DEEP LOW CONTINUES TO ADVANCE EAST. STRONG PRESSURE GRADIENT WITH THE LOW WILL BRING SOLID STORM-FORCE WINDS...WITH POSSIBLE HIGHER GUSTS TO THE CENTRAL ALEUTIANS ISLANDS AND MARINE ZONES BOTH AHEAD AND BEHIND THE LOW WEDNESDAY AND THURSDAY. .LONG TERM FORECAST... NO REAL CHANGES TO THE LONG-TERM PATTERN. STAYING ACTIVE ACROSS THE AOR...AS LOW PRESSURE SYSTEMS ROTATE UP THE GULF TOWARDS THE SOUTHERN MAINLAND AND EJECT OUT OF THE BERING TOWARDS THE SW MAINLAND AND ALEUTIAN CHAIN INTO THE FIRST PART OF NEXT WEEK. .AER/ALU...WATCH/WARNING SUMMARY PUBLIC...NONE MARINE...STORM...411 413 172 175 176 GALE...351 352 120 130 132 412 414 150 155 160 165 170 171 179 180 185 HEAVY FREEZING SPRAY...180 JAM NOV 09