Small Craft Advisory 888, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
502 PM AKST SUN NOV 8 2015

UPDATED ADVISORY LIST

.ANALYSIS AND UPPER LEVELS...

AN UPPER LEVEL LOW IS CURRENTLY CENTERED IN THE NORTHERN
BERING...AND ENCOMPASSES MUCH OF THE BERING AND MAINLAND
ALASKA. AN IMPRESSIVE 959MB LOW HAS DEVELOPED AT THE SURFACE
BENEATH THIS LOW. AN ASSOCIATED OCCLUDED FRONT STRETCHES ALL THE
WAY FROM THE LOW TO THE PACIFIC...AND IS TAPPING INTO A RICH
SUPPLY OF TROPICAL MOISTURE. ALREADY TODAY THIS SYSTEM HAS BEEN
SUPPORTING WIDESPREAD PRECIPITATION ACROSS THE KUSKOKWIM DELTA AND
BRISTOL BAY REGIONS. IN ADDITION...THE ASSOCIATED LOW LEVEL JET
HAS BEEN SUPPORTING GUSTY WINDS ALONG THE KUSKOKWIM DELTA COAST
THIS MORNING. THE LATEST RADAR IMAGES INDICATE THAT THIS MOISTURE
IS BEGINNING TO EFFECT SOUTHERN AND WESTERN PORTIONS OF
SOUTHCENTRAL...WHICH IS THE BEGINNING OF THE WIDESPREAD SNOW EVENT
THAT WILL IMPACT MUCH OF SOUTHCENTRAL THIS EVENING.

TO THE WEST OF THIS FRONT...WIDESPREAD SHOWERS HAVE BEEN
DEVELOPING IN THE COLDER AND DRIER AIR BEHIND THE FRONT...WHICH A
FEW LIGHTNING STRIKES NEAR THE PRIBILOFS AND THE WESTERN BERING.

&&

.MODEL DISCUSSION...
MODELS CONTINUE TO BE IN GREAT AGREEMENT IN CAPTURING THE
IMPRESSIVE DYNAMICS OF THE LOW THAT ENCOMPASSES MUCH OF THE
REGION. THE MOST SIGNIFICANT DIFFERENCE IN MODELS CONTINUES TO BE
THE MAGNITUDE OF DOWNSLOPING IN THE TYPICALLY DOWNSLOPED AREAS OF
SOUTHCENTRAL INCLUDING THE ANCHORAGE BOWL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE ROBUST OCCLUDED FRONT THAT IS ASSOCIATED WITH THE BERING SEA
LOW IS BEGINNING TO MOVE INTO SOUTHCENTRAL ALASKA THIS
AFTERNOON. SNOW IS EXPECTED TO CONTINUE TO DEVELOP OVER THE
REGION THROUGH THE EVENING HOURS...BECOMING HEAVY DURING THE LATE
EVENING HOURS. THE HEAVIEST AMOUNTS ARE STILL EXPECTED IN THE
SUSITNA VALLEY THROUGH LATE TONIGHT. SNOW AMOUNTS ARE EXPECTED TO
BE LOWER FURTHER SOUTH WITH 4 TO 8 INCHES IN THE MATANUSKA VALLEY
AND 3 TO 6 INCHES IN THE ANCHORAGE AREA THROUGH LATE TONIGHT.
WINDS HAVE ALREADY STARTED TO INCREASE ALONG TURNAGAIN ARM IN
RESPONSE TO THE FRONT AND WILL BEGIN TO RAPIDLY DECREASE AFTER
MIDNIGHT. AFTER THE THE FRONT PUSHES EAST INTO THE COPPER RIVER
BASIN...SOUTHWEST FLOW UP COOK INLET WILL KEEP AN UPSLOPED AND
SHOWERY PATTERN IN PLACE MONDAY. FOR THE ANCHORAGE AREA AND
MATANUSKA VALLEY...THIS SHOULD PRODUCE ABOUT AN ADDITIONAL INCH OF
SNOW ACCUMULATION ON MONDAY WITH MOST OF THE ACCUMULATION IN THE
MORNING HOURS.

AFTER THE FRONT PUSHES OUT OF THE REGION LATE MONDAY EVENING...BROAD
CYCLONIC FLOW WILL CONTINUE OVER THE AREA WITH MAINLY NORTHWESTERLY
FLOW ALOFT. THIS WILL KEEP SHOWERY PRECIPITATION IN THE FORECAST
FOR SOUTHCENTRAL WITH COOLING TEMPERATURES THROUGH TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2...MON AND
TUE)...THE FRONT ASSOCIATED WITH THE DEEPENING LOW IS PUSHING
THROUGH THE SOUTHWEST THIS EVENING. IT HAS CLEARED TO THE EAST OF
KING SALMON AND BETHEL...AND SATELLITE AND RADAR CLEARLY SHOW A
VERY UNSTABLE WELL MIXED COLD AIR ADVECTION ATMOSPHERE BEHIND IT.
THE GUSTY SOUTHERLY WINDS ARE ALSO SHIFTING TO A MORE SOUTHWEST TO
WEST DIRECTION. THE STRONGEST WINDS SHOULD REMAINED CONFINED TO
THE COASTAL AREAS THROUGH THE OVERNIGHT HOURS...BUT SOME GUSTS TO
50 MPH WILL BE ABLE TO MAKE THEIR WAY INLAND. WITH THE EXCEPTION
OF INLAND VALLEYS IN THE LOWER KUSKOKWIM...ALL PLACES WARMED
ENOUGH TO CHANGE OVER TO RAIN TODAY. AS COLD AIR BLEEDS IN THROUGH
THE NIGHT...MOST LOCATIONS WILL CHANGE BACK TO SNOW. ACCUMULATIONS
SHOULD BE LIMITED THOUGH WITH TEMPERATURES NEAR FREEZING. SOME OF
THE SHOWERS...ESPECIALLY OVER THE KUSKOKWIM DELTA...COULD PRODUCE
HEAVY SNOW FOR BRIEF PERIODS. WHEN COUPLED WITH THE GUSTY WINDS...
VISIBILITY COULD DROP TO ONE MILE AT TIMES.

MON INTO TUE...WESTERLY FLOW ON THE BACKSIDE OF THE LOW WILL
CONTINUE TO PUSH SHOWERS FROM THE EASTERN BERING OVER THE
MAINLAND. GUSTY WINDS WILL SLOWLY DIMINISH AS THE LOW FILLS AND
DRIFTS NORTHEAST. ONE LAST PIECE OF POTENT ENERGY WILL WRAP AROUND
THE LOW AND PUSH INTO BRISTOL BAY MON NIGHT. THIS SHOULD TRIGGER
ANOTHER ROUND OF HEAVIER PRECIPITATION AND GUSTY WINDS FROM THE
WESTERN CAPES THROUGH THE ALASKA PENINSULA. WE ALSO CAN'T RULE OUT
THE POSSIBILITY OF ISOLATED THUNDERSTORMS OVER THE ALASKA
PENINSULA WITH A POCKET OF -40 C 500 MB TEMPERATURES MOVING OVER
THE WARMER WATERS. THIS WAVE WILL ALSO BE RIGHT ALONG THE LEFT
EXIT REGION OF THE JET WHICH WILL AID IN VERTICAL DEVELOPMENT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2...MON AND
TUE)...THE LOW OVER THE NORTHERN BERING WILL BE THE DOMINATE FEATURE.
IT WILL KEEP THE ENTIRE AREA UNDER UNSTABLE WEST TO NORTHWEST FLOW.
THIS WILL MAKE FOR GUSTY WINDS...COLD SHOWERS...AND OCCASIONAL
LIGHTNING STRIKES. IT WILL ALSO CONTINUE TO PULL COLD AIR OFF OF
RUSSIA AND CAUSE PRECIPITATION TO MIX WITH AND EVENTUALLY TURN
OVER TO SNOW THROUGHOUT MUCH OF THE AREA. WE SHOULD NOT SEE MUCH
AT ALL IN THE WAY OF ACCUMULATION WITH GROUND TEMPERATURES STILL
WELL ABOVE FREEZING.

THE NEXT MAJOR FEATURE WILL BE ANOTHER RAPIDLY DEEPENING CYCLONE NEAR
THE CENTRAL ALEUTIANS TUE INTO WED. SEE THE EXTENDED DISCUSSION FOR
MORE DETAILS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MODELS ARE DEPICTING A VIGOROUS NORTH PACIFIC LOW UNDERGOING
EXPLOSIVE CYCLOGENESIS AS IT TRACKS NEAR KISKA BY TUESDAY MORNING.
THIS SYNOPTIC FEATURE WILL BRING WIDESPREAD RAIN AND STRATUS WITH
STRONG GUSTY SOUTH TO SOUTHWESTERLY WINDS ON THE FRONT SIDE OF THE
LOW AS IT CONTINUES TO TRACK ALONG THE CHAIN. THIS SYSTEM WILL
CROSS THE CHAIN AND TRACK JUST NORTHEAST OF DUTCH HARBOR BY LATE
TUESDAY NIGHT. RESULTING IN THE POTENTIAL FOR HURRICANE-FORCE
WINDS ON THE BACKSIDE OF THIS LOW PRESSURE SYSTEM. THEREFORE...THE
CENTRAL TO EASTERN ALEUTIANS WILL HAVE STRONG NORTHWESTERLY WINDS
WITH THE POSSIBILITY OF HIGH WIND WATCHES/WARNINGS AS THIS SYSTEM
CONTINUES TO TRACK ALONG THE CHAIN BEFORE CROSSING OVER NEAR THE
SOUTHERN END OF KODIAK ISLAND BY WEDNESDAY EVENING. THE NAM/EC
MODELS ARE IN VERY GOOD AGREEMENT EXCEPT FOR THE GFS BEING FASTER
WITH THIS SYSTEM. THE BERING AND ALEUTIAN CHAIN WILL REMAIN UNDER
NORTHWESTERLY FLOW AS WE HEAD INTO THE WEEKEND. THE 850 MB
TEMPERATURES IN THE BERING SEA ARE SHOWING GOOD COLD AIR ADVECTION
WITH THE 850 MB TEMPERATURES STARTING OUT IN THE -5 DEGREE
CELSIUS RANGE BEFORE DROPPING TO -15 DEGREE CELSIUS RANGE BY THE
MIDWEEK WITH THE AFOREMENTIONED SYNOPTIC FEATURE.

THE WESTERN GULF WILL SEE THE ARRIVAL OF STORM FORCE WINDS THROUGH
THE BARREN ISLANDS AND THE SOUTHERN END OF THE COOK INLET AS THE
STORM FORCE LOW TRACKS EAST OF KODIAK ISLAND BY WEDNESDAY EVENING.
THIS WILL BRING WIDESPREAD RAIN AND STRATUS TO THE GULF AS THIS
SYSTEM TRACKS NEAR YAKUTAT BY THURSDAY. THE WESTERN GULF WILL
TRANSITION TO NORTHWESTERLY GAP WINDS BY THURSDAY AS THE COLDER
AIR FILTERS INTO THE REGION. THE SOUTHERN MAINLAND WILL HAVE
ONSHORE FLOW IN THE EARLY PART OF THIS UPCOMING WEEK BEFORE
TRANSITIONING TO OFFSHORE FLOW AS THE LOW PRESSURE SYSTEM TRACKS
TO THE NORTHERN GULF. THIS WILL BRING COLDER TEMPERATURES
COINCIDING WITH THE NORTHWESTERLY TO NORTHERLY WINDS TO THE
SOUTHCENTRAL REGION.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WSW HEAVY SNOW 145...SNOW ADVISORY 101 111. HIGH SURF
ADVISORY 155.
MARINE...STORM WARNINGS 180 181 185. GALE WARNINGS
119 120 130 131 132 136 137 138 150 155 160 165 170 172 173 174
175 176 177 178 179 351 352 411 412 413.

&&

SYNOPSIS AND MODEL DISCUSSION...EN
SOUTHCENTRAL ALASKA...RF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MO
LONG TERM...PD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1039 PM AKST SUN NOV 08 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1036 PM     SNOW             9 NW BENTALIT           61.64N 150.81W
11/08/2015  M8.0 INCH                           AK   TRAINED SPOTTER

            TOTAL ACCUMULATION SINCE SNOWFALL BEGAN AT 4PM. HEAVY
            SNOW ONGOING. 24 DEGREES. CALM WIND.

&&

JPW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1230 AM AKST MON NOV 09 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1230 AM     SNOW             5 SSE ANCHORAGE         61.15N 149.82W
11/09/2015  M1.5 INCH                           AK   TRAINED SPOTTER

            SNOW TOTAL AS OF MIDNIGHT. SNOW WITH SOME RAIN MIXED. WET
            SNOW. 33 DEGREE TEMPERATURE.

1230 AM     SNOW             6 SW ANCHORAGE          61.15N 149.98W
11/09/2015  M2.3 INCH                           AK   OFFICIAL NWS OBS

            0.1 INCHES BEFORE 9PM...2.2 INCHES 9PM TO MIDNIGHT.

&&

JPW