103  
FXAK68 PAFC 251345  
AFDAFC  
 
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ANCHORAGE AK  
545 AM AKDT MON OCT 25 2021  
   
ANALYSIS AND UPPER LEVELS
 
 
A COMPACT LOW CENTERED SOUTH OF SEWARD IS SPREADING LIGHT  
RAIN/SPRINKLES ACROSS THE EASTERN KENAI PENINSULA. A NARROW BAND  
OF SOMEWHAT HEAVIER RAIN IS MOVING NEAR SEWARD. ELSEWHERE, NEARLY  
ALL OF SOUTHCENTRAL AND SOUTHWEST ALASKA IS QUIET WITH WEAK HIGH  
PRESSURE OVER THE AREA. UNLIKE THE PRECIPITATION, THE CLOUD COVER  
IS QUITE EXTENSIVE OVER MUCH OF SOUTHERN ALASKA, WITH LOW CLOUDS  
AND EVEN A BIT OF LIGHT SNOW OVER THE LOWER KUSKOKWIM VALLEY, AND  
CLOUD COVER FROM THE GULF LOW SPREADING NORTH OVER MUCH OF  
SOUTHCENTRAL. A STORM FORCE LOW THAT TRACKED ALONG THE ALEUTIAN  
CHAIN YESTERDAY IS BEGINNING TO MAKE ITS EXIT BACK INTO THE NORTH  
PACIFIC SOUTH OF THE AKPEN.  
 
IN THE UPPER LEVELS, THE FLOW REMAINS LARGELY CHAOTIC OVER MUCH OF  
SOUTHERN MAINLAND ALASKA, THOUGH ON AVERAGE, THE UPPER LEVEL FLOW  
IS ABOUT 10 TO 20 KTS OUT OF THE SOUTH IN THE MID-LEVELS. THE  
SUBTROPICAL PACIFIC JET IS NOW ZONAL AND IS CENTERED SOUTH OF 50N,  
AND THEREFORE REALLY NOT IMPACTING THE STATE AT ALL THIS MORNING.  
 

 
   
MODEL DISCUSSION
 
 
MODEL AGREEMENT IS GOOD ON THE LARGE SCALE THIS MORNING. FOR THE  
MOST PART, THE WEATHER REMAINS QUIET OVER NEARLY ALL OF THE AREA.  
THE STORM FORCE LOW WHICH TRACKED THE LENGTH OF THE ALEUTIAN CHAIN  
YESTERDAY IS NOW MOVING SOUTH OF ALASKA AS IT HEADS SOUTH OF THE  
GULF. IT WILL MOVE INTO THE PANHANDLE TUESDAY, AT WHICH POINT IT  
MAY DRIFT BACK WESTWARD AS IT WEAKENS, WHICH MAY CAUSE SOME  
PRECIPITATION ALONG THE COAST TO PRINCE WILLIAM SOUND BY  
WEDNESDAY. THERE ARE SOME TIMING DIFFERENCES WITH A WEAK LOW  
APPROACHING THE KUSKOKWIM DELTA TUESDAY EVENING, BUT IMPACTS FROM  
THIS LOW REGARDLESS WERE MINIMAL. FORECAST CONFIDENCE IS HIGH.  
 

 
   
AVIATION
 
 
PANC...VFR CONDITIONS AND LIGHT WINDS WILL PERSIST.  
 

 
 
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 THROUGH 2:  
MONDAY THROUGH TUESDAY NIGHT)...  
 
LOW PRESSURE OVER THE GULF IS WEAKENING THIS MORNING WHILE  
SUSTAINING LIGHT SHOWERS OVER PRINCE WILLIAM SOUND AND PORTIONS OF  
THE KENAI PENINSULA. THIS LOW WILL EVENTUALLY LIFT NORTHWARD INTO  
SOUTHCENTRAL ON TUESDAY AND DISSIPATE. HOWEVER, LINGERING SHOWERS  
MAY PERSIST THROUGH THE MORNING HOURS ON MONDAY FOR PORTIONS OF  
KODIAK WHILE OFF AND ON RAIN MAY PERSIST INTO THE OVERNIGHT HOURS  
FOR CORDOVA. ANY ADDITIONAL AREAS OF PRECIPITATION WILL GRADUALLY  
CLEAR OUT WITH PARTLY CLOUDY SKIES FOR MUCH OF THE DAY THROUGHOUT  
SOUTHCENTRAL. MOSTLY BENIGN CONDITIONS ARE FORECAST THE NEXT  
COUPLE OF DAYS WITH A LACK OF ANY SIGNIFICANT AREAS OF FORCING OR  
TROUGH MOVEMENT THROUGH THE REGION. THE ARRIVAL OF COLDER AIR  
FILTERING IN FROM THE NORTH AND NORTHWEST IS ANTICIPATED ON  
TUESDAY AND TUESDAY NIGHT WITH A FEW FLURRIES POSSIBLE FOR THE  
ANCHORAGE BOWL EARLY ON WEDNESDAY. LIGHT SNOW WILL ALSO BE  
POSSIBLE ACROSS THE TALKEETNAS INTO THE COPPER BASIN WITH  
NEGLIGIBLE ACCUMULATIONS. OTHERWISE, THE COLDER UPPER TEMPERATURES  
ARE FORECAST TO BRING INCREASINGLY GUSTY WINDS TO OUTFLOW PRONE  
REGIONS ALONG THE COAST, INCLUDING WEST AND EAST OF THE BARREN  
ISLANDS, ACROSS SEWARD AND RESURRECTION BAY, VALDEZ PORT, AS WELL  
AS THOMPSON PASS BY THE MIDDLE OF THE WEEK.  
 

 
   
SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 TO 2)
 
 
A GENERALLY QUIET PATTERN IS IN TRACK TO CONTINUE OVER THE COURSE  
OF THE NEXT COUPLE DAYS. COOL NORTHERLY FLOW WILL CONTINUE EAST  
OF A SHORTWAVE RIDGE CENTERED OVER THE BERING, KEEPING CONDITIONS  
DRY BY AND LARGE WITH PARTLY CLOUDY SKIES THROUGH TUESDAY.  
OCCASIONAL SNOW SHOWERS ARE POSSIBLE NEAR THE KUSKOKWIM DELTA  
COAST AS THEY MOVE ONSHORE FROM THE BERING WITH WEAK WAVES PASSING  
THROUGH ALOFT. TEMPERATURES ARE SEASONABLY COOL, WITH HIGHS  
AROUND THE FREEZING MARK TODAY AND TUESDAY AND INLAND LOWS DIPPING  
INTO THE 10S FOR MOST AREAS FOR EARLY TUESDAY AND WEDNESDAY  
MORNINGS.  
 
ON TUESDAY AFTERNOON, A LOW MOVING OFF OF KAMCHATKA WILL ENTER THE  
NORTHERN BERING AND DROP SOUTH BETWEEN THE PRIBILOFS AND NUNIVAK  
ISLAND BY WEDNESDAY MORNING. THIS SHOULD BRING A FRONT ONSHORE AT  
SOME POINT ALONG THE SOUTHWEST COAST, ALTHOUGH MODELS VARY  
SOMEWHAT WITH THE PROGRESSION OF BOTH THE FRONT AND ITS PARENT  
LOW BY THIS POINT IN TIME. THE FASTER SOLUTIONS BRING A BAND OF  
POTENTIALLY MODERATE SNOWFALL INTO PARTS OF THE Y-K DELTA AND  
NORTHERN BRISTOL BAY BY AROUND MIDDAY WEDNESDAY, WITH SLOWER  
SOLUTIONS KEEPING FRONTAL PRECIP LIMITED TO COASTAL LOCATIONS  
UNTIL LATER IN THE DAY. THE CURRENT FORECAST REFLECTS A MIDDLE  
GROUND SOLUTION, WITH SNOWFALL SPREADING SLOWLY INLAND FROM WEST  
TO EAST ON WEDNESDAY MORNING.  
 

 
   
SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 TO 2)
 
 
A NORTH PACIFIC LOW SOUTH OF THE ALASKA PENINSULA THIS MORNING  
WILL EXIT THE PICTURE BY THIS AFTERNOON AS IT MOVES OUT TOWARDS  
THE GULF, WITH EASTERLY GALE FORCE WINDS ALONG AND SOUTH OF THE  
EASTERN ALEUTIANS QUICKLY SUBSIDING. A HIGH PRESSURE RIDGE WILL  
MOVE OVER THE BERING IN ITS PLACE FROM TONIGHT INTO TUESDAY,  
YIELDING A SHORT BREAK IN THE ACTIVE WEATHER FOR MUCH OF THE  
REGION. GAP WINDS ON TUESDAY WILL PICK UP THROUGH THE SOUTHERN  
AKPEN AS NORTHERLY FLOW STRENGTHENS BETWEEN THE BERING RIDGE AND  
LOW MOVING SOUTH OF THE GULF. WIDELY SCATTERED CONVECTIVE RAIN AND  
SNOW SHOWERS WILL CONTINUE OVER MUCH OF THE BERING AS COLD AIR  
ADVECTING OVER THE SEA SURFACE PICKS UP MOISTURE AND WARMTH AND  
BECOMES UNSTABLE NEAR SEA LEVEL.  
 
A KAMCHATKA LOW WILL DROP SOUTH INTO THE NORTHERN BERING LATE ON  
TUESDAY, BRINGING ANOTHER ROUND OF MORE ACTIVE WEATHER BACK INTO  
PLAY. GALES ARE NOW ANTICIPATED TO WRAP AROUND THE WESTERN SIDE OF  
THE SYSTEM, SPREADING SOUTH TOWARDS THE PRIBILOFS ON WEDNESDAY  
MORNING. A SWIFTLY MOVING BAND OF MOSTLY RAIN MIXING WITH SNOW  
WILL MOVE OUT AHEAD OF THE LOW ALONG ITS FRONT, PASSING OVER THE  
PRIBILOFS TUESDAY NIGHT AND MOVING SOUTHEAST INTO THE ALEUTIANS BY  
EARLY WEDNESDAY MORNING.  
 

 
   
MARINE (DAYS 3 THROUGH 5: WEDNESDAY THROUGH FRIDAY)
 
 
CONFIDENCE IS HIGH WITH A BENIGN PATTERN SETTING UP FOR THE GULF  
OF ALASKA WATERS THROUGH FRIDAY. WEAK LOW PRESSURE WILL DEVELOP  
NEAR PRINCE WILLIAM SOUND WEDNESDAY NIGHT BEFORE MOVING OVER  
CANADA. THURSDAY NIGHT AND INTO FRIDAY, LOW PRESSURE WILL TRACK  
NEAR KODIAK. AN ATTENDANT FRONT WILL MOVE NORTH, POTENTIALLY  
CREATING A GALE FORCE BARRIER JET FRIDAY EVENING.  
 
A SIBERIAN LOW WILL MOVE INTO THE NORTHERN BERING WEDNESDAY. THIS  
LOW WILL DEEPEN AS IT MOVES TOWARDS BRISTOL BAY THURSDAY,  
PROVIDING LOW END GALES, WITH HIGHER END GALES POSSIBLE. LOW  
PRESSURE DEVELOPING OFF OF THE COAST OF JAPAN EARLY THIS WEEK WILL  
MOVE NORTH TOWARDS THE ALEUTIAN WATERS. CONFIDENCE REMAINS LOW ON  
THE FORECAST TRACK. PRESENTLY IT REMAINS SOUTH OF THE FORECAST  
MARINE AREA.  
 

 
 
.LONG TERM DISCUSSION (DAYS 4 THROUGH 7: THURSDAY THROUGH  
SUNDAY)...  
 
LOW PRESSURE THAT IS DEVELOPING NEAR JAPAN WILL BE THE PRIMARY  
WEATHER MAKER INTO THE LONG TERM FORECAST. THE FORECAST CHALLENGES  
FOR THE ALEUTIANS WILL BE HOW FAR NORTH THIS LOW MOVES. AMERICAN  
GUIDANCE LIFTS IT CLEAR ACROSS ADAK, WHILE EUROPEAN GUIDANCE KEEPS  
IT A FEW HUNDRED NAUTICAL MILES SOUTH. BY THE WEEKEND, THE  
PICTURE DOES GET A LITTLE CLEARER AS A FRONT WILL LIFT NORTH  
ACROSS THE GULF OF ALASKA AND IMPACT THE COAST OF SOUTH CENTRAL  
AND KODIAK. FOR COASTAL AREAS FACING THE GULF AND INLAND AREAS  
NEAR COOK INLET, FREEZING LEVELS ARE PROGGED TO BE IN THE 2.5 TO 3  
KFT RANGE, KEEPING COLD RAIN IN THE FORECAST FROM HOMER THROUGH  
PALMER. MEANWHILE THE CHUGACH AND PARTS OF THE ALASKA, TALKEETNA  
AND WRANGELL RANGES WILL SEE SNOW ABOVE. TEMPERATURES ARE NOT  
EXPECTED TO DEVIATE MUCH FROM NORMAL FOR THIS TIME OF YEAR.  
 

 
 
   
AFC WATCHES/WARNINGS/ADVISORIES
 
 
PUBLIC...NONE.  
MARINE...GALE WARNING: 130 131 138 150.  
 

 
 
SYNOPSIS AND MODEL DISCUSSION...JPW  
SOUTHCENTRAL ALASKA...BL  
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AS  
MARINE/LONG TERM...SS  
 
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