Gale Warning 549, NWS Anchorage, AK

456 
FZAK61 PAFC 281134
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
334 AM AKDT MON SEP 28 2015

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

WIND FORECASTS REFLECT THE PREDOMINANT SPEED AND DIRECTION
EXPECTED. SEA FORECASTS REPRESENT AN AVERAGE OF THE HIGHEST
ONE-THIRD OF THE COMBINED WIND WAVE AND SWELL HEIGHT.

PKZ399-290145-
334 AM AKDT MON SEP 28 2015
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 993 MB LOW NEAR 52N 157W MON AFTERNOON WILL MOVE TO 60N 146W AT
974 MB TUE MORNING. IT WILL THEN REMAIN NEARLY STATIONARY THROUGH
TUE NIGHT AND WEAKEN TO 990 MB.

$$

PKZ351-290145-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
334 AM AKDT MON SEP 28 2015

...GALE WARNING TUESDAY...

.TODAY...SW WIND 20 KT. SEAS 7 FT. RAIN.
.TONIGHT...S WIND 20 KT BECOMING 20 TO 30 KT AFTER MIDNIGHT. SEAS
7 TO 10 FT. RAIN.
.TUE...W WIND 25 TO 40 KT. SEAS 10 TO 18 FT. RAIN.
.TUE NIGHT...W WIND 30 TO 45 KT. SEAS 16 TO 24 FT.
.WED...NW WIND 20 TO 35 KT. SEAS 9 TO 17 FT.
.THU THROUGH FRI...S WIND 10 TO 20 KT. SEAS 4 TO 7 FT.

$$

PKZ352-290145-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
334 AM AKDT MON SEP 28 2015

...GALE WARNING TONIGHT AND TUESDAY...

.TODAY...SW WIND 20 KT. SEAS 8 FT. RAIN.
.TONIGHT...S WIND 10 TO 25 KT INCREASING TO SW 25 TO 40 KT AFTER
MIDNIGHT. SEAS 8 TO 14 FT. RAIN.
.TUE...W WIND 25 TO 40 KT INCREASING TO 35 TO 45 KT IN THE
AFTERNOON. SEAS 10 TO 18 FT BUILDING TO 17 TO 22 FT IN THE
AFTERNOON. RAIN.
.TUE NIGHT...W WIND 35 TO 45 KT. SEAS 16 TO 24 FT.
.WED...NW WIND 15 TO 30 KT. SEAS 10 TO 18 FT.
.THU THROUGH FRI...S WIND 10 TO 20 KT. SEAS 4 TO 9 FT.

$$

417 
FZAK61 PAFC 282333
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
333 PM AKDT MON SEP 28 2015

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

WIND FORECASTS REFLECT THE PREDOMINANT SPEED AND DIRECTION
EXPECTED. SEA FORECASTS REPRESENT AN AVERAGE OF THE HIGHEST
ONE-THIRD OF THE COMBINED WIND WAVE AND SWELL HEIGHT.

PKZ399-291400-
333 PM AKDT MON SEP 28 2015
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...A FRONT IN THE WESTERN
GULF APPROACHES THE EASTERN GULF BY TUESDAY AFTERNOON. A 987 MB
NORTH PACIFIC LOW MOVES INLAND NEAR 60N 144W TUESDAY MORNING AT
969 MB...THEN MOVES TO 59N 144W WED AFTERNOON AT 1001 MB.

$$

PKZ351-291400-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
333 PM AKDT MON SEP 28 2015

...STORM WARNING TUESDAY NIGHT...

.TONIGHT...S WIND 10 TO 25 KT INCREASING TO 20 TO 35 KT AFTER
MIDNIGHT. SEAS 7 TO 12 FT. RAIN.
.TUE...S TO W WIND 25 TO 35 KT INCREASING TO 35 TO 45 KT IN THE
AFTERNOON. SEAS 10 TO 17 FT BUILDING TO 16 TO 24 FT IN THE
AFTERNOON. RAIN.
.TUE NIGHT...W WIND 35 TO 50 KT. SEAS 18 TO 26 FT. RAIN.
.WED...NW WIND 20 TO 35 KT. SEAS 12 TO 20 FT.
.WED NIGHT...N WIND 15 TO 30 KT. SEAS 7 TO 12 FT.
.THU THROUGH SAT...SW WIND 10 TO 25 KT. SEAS 4 TO 9 FT.

$$

PKZ352-291400-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
333 PM AKDT MON SEP 28 2015

...STORM WARNING TUESDAY...

.TONIGHT...S WIND 15 TO 30 KT BECOMING S TO W 25 TO 40 KT AFTER
MIDNIGHT. SEAS 7 TO 10 FT BUILDING TO 9 TO 17 FT AFTER MIDNIGHT.
RAIN.
.TUE...W WIND 30 TO 45 KT INCREASING TO 40 TO 50 KT IN THE
AFTERNOON. SEAS 14 TO 21 FT BUILDING TO 20 TO 26 FT IN THE
AFTERNOON. RAIN.
.TUE NIGHT...W WIND 45 KT. SEAS 19 TO 27 FT.
.WED...NW WIND 20 TO 35 KT. SEAS 13 TO 21 FT.
.WED NIGHT...NW WIND 15 TO 30 KT. SEAS 9 TO 14 FT.
.THU THROUGH SAT...SW WIND 10 TO 25 KT. SEAS 5 TO 10 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
458 AM AKDT SUN SEP 27 2015

.ANALYSIS AND UPPER LEVELS...
A PROGRESSIVE AND MOISTURE RICH ZONAL FLOW PATTERN IS KEEPING
LIGHT RAIN AND WIDESPREAD LOW CLOUDS OVER THE BULK OF THE SOUTHERN
MAINLAND THIS MORNING AS FLOW BEGINS TO SHIFT FROM THE WEST TO
THE SOUTHWEST AHEAD OF A LOW AMPLITUDE UPPER TROUGH LIFTING
NORTHEASTWARD ACROSS THE BERING SEA. AN ASSOCIATED SURFACE LOW IS
BEGINNING TO SPREAD HEAVIER RAIN OVER THE KUSKOKWIM DELTA AND
OTHER PORTIONS OF SOUTHWEST ALASKA AS IT TRACKS TOWARDS NUNIVAK
ISLAND...WITH SOUTHEASTERLY GAP WINDS BEGINNING TO INCREASE ACROSS
FAVORED PORTIONS OF SOUTHCENTRAL AK IN RESPONSE TO THE TIGHTENING
PRESSURE GRADIENT.

&&

.MODEL DISCUSSION...
GUIDANCE REMAINS IN STRONG SYNOPTIC AGREEMENT IN THE SHORT TERM AS
THE CURRENT MOIST ZONAL FLOW PATTERN GIVES WAY TO A HIGHLY
AMPLIFIED TROUGH DIVING OUT OF EASTERN RUSSIA EARLY IN THE WEEK.
THE LOW AMPLITUDE BERING TROUGH AND ASSOCIATED SURFACE LOW WILL
CONTINUE TO SUPPORT WIDESPREAD RAIN AND CLOUDS THROUGH TONIGHT AS
THEY PUSH INTO THE INTERIOR AND YIELD SOUTHWEST FLOW OVER THE
SOUTHERN MAINLAND. ATTENTION THEN TURNS TO NEXT TROUGH AS IT
SWINGS ACROSS THE BERING AND DEEPENS OVER WESTERN ALASKA ON MONDAY
BEFORE TAKING ON A NEGATIVE TILT AS IT PUSHES THROUGH SOUTHCENTRAL
AK ON TUESDAY. THIS WILL ALLOW UNSEASONABLY COLD AIR TO FILTER
INTO THE REGION AS A SURFACE LOW FORMING IN THE VICINITY OF
PRINCE WILLIAM SOUND PROVIDES A SOURCE OF MOISTURE. THE STRONG
OVERALL AGREEMENT IN THIS SCENARIO LENDS INCREASING CONFIDENCE
THAT INLAND PORTIONS OF SOUTHCENTRAL AK WILL SEE SNOWFALL AT SEA
LEVEL MONDAY NIGHT INTO TUESDAY. HOWEVER...THE SPECIFIC DETAILS OF
THE FORECAST REMAIN UNRESOLVED AT THIS TIME GIVEN MODEST
DIFFERENCES IN TIMING AND INTENSITY OF THESE FEATURES.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE DUE WEST UPPER LEVEL FLOW HAS CAUSED SLOW BUT STEADY WARMING
OF THE TEMPERATURES ALOFT OVER THE PAST DAY RESULTING IN A
WIDESPREAD LOW CLOUDS AND LIGHT RAIN OVER MUCH OF SOUTHCENTRAL
ALASKA. AS THIS FLOW ALOFT BECOMES SOUTHWEST TODAY AND THE LOWER
LEVEL WIND BECOME GENERALLY SOUTHEAST IT WILL INCREASE THE
RAINFALL RATES AND ALSO LIFT THE CLOUD CEILINGS SOME AS WELL. THE
SOUTHWEST FLOW ALOFT USHERING IN LARGE AMOUNTS OF MOISTURE AND
LIFT WILL CONTINUE THROUGH MONDAY. THERE MAY BE A BRIEF BREAK
MONDAY NIGHT OVER THE COOK INLET REGION BEFORE THE COLD FRONT
MOVES INTO THE AREA TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
STEADY RAIN WILL OVER SOUTHWEST THIS MORNING AS THE OCCLUDED
FRONT MOVES THROUGH THE AREA. THE HEAVIEST RAIN WILL LIKELY OCCUR
ALONG THE FRONT FROM THE EASTERN KUSKOKWIM DELTA TO THE LOWER
KUSKOKWIM VALLEY EARLY THIS MORNING...AND AGAIN LATER THIS MORNING
THROUGHOUT THE AREA AS THE RAIN IS REINVIGORATED FROM A SHORTWAVE
MOVING OVER THE SOUTHWEST COAST FROM THE BERING. THE LOW WILL THEN
MAKE LANDFALL OVER THE KUSKOKWIM DELTA THIS AFTERNOON...KEEPING
RAIN IN THE AREA INTO THIS EVENING.

BY LATE THIS EVENING...A COLD FRONT DRAPED BEHIND THE LOW WILL
CAUSE THE WINDS TO SHIFT TO NORTHWESTERLY AND DRAG COLD SIBERIAN
AIR BEHIND IT. 850 MB TEMPERATURES WILL PLUMMET TO AROUND 8C BY
EARLY MONDAY MORNING NEAR BETHEL...MORE THAN COLD ENOUGH TO CAUSE
RAIN SHOWERS IN THE AREA TO SWITCH OVER TO SNOW. THIS COLD AIR
WILL THEN RAPIDLY SPREAD EASTWARD INTO THE KUSKOKWIM
DELTA...CAUSING RAIN TO MIX OR SWITCH OVER TO SNOW. HOWEVER WITH
THE WARM AND MOIST AIRMASS CURRENTLY OVER THE AREA...SURFACE
TEMPERATURES ARE NOT EXPECTED TO FALL ENOUGH TO ALLOW FOR
SIGNIFICANT ACCUMULATIONS...BUT LOCALIZED AREAS OF AROUND AN INCH
WOULD CERTAINLY BE POSSIBLE. AN UPPER LEVEL TROUGH WILL THEN
APPROACH THE WEST COAST ON MONDAY AFTERNOON...KEEPING RAIN AND
SNOW SHOWERS IN THE AREA THROUGH MONDAY NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
RAIN AND SOUTHWESTERLY WINDS WILL CONTINUE TODAY FOR MUCH OF THE
EASTERN BERING AND ALEUTIANS AS THE LOW OVER THE NORTHERN BERING
PROGRESSES TOWARDS THE COAST. BEHIND THIS LOW...A COLD FRONT WILL
CAUSE WINDS THROUGHOUT THE AREA TO SHIFT TO NORTHWESTERLY BY LATE
TONIGHT...SETTING UP A SHOWERY COLD AIR ADVECTION REGIME THAT WILL
CONTINUE THROUGH MONDAY. THERE WILL ALSO BE ENOUGH COLD AIR BEHIND
THE FRONT TO CAUSE RAIN TO MIX WITH SNOW FROM THE PRIBILOFS INTO
THE AKPEN...HOWEVER WITH THE WARM SEA SURFACE TEMPERATURES THIS IS
NOT EXPECTED TO ACCUMULATE. AN UPPER LEVEL TROUGH DIVING INTO THE
BERING FROM SIBERIA WILL REINVIGORATE RAIN AND SNOW SHOWERS AS IT
PASSES OVER. THIS TROUGH WILL ALSO BRING INCREASED NORTHWESTERLY
WINDS TO THE AKPENN ON MONDAY NIGHT AS IT PASSES OVERHEAD...BUT
WITHOUT GOOD JET SUPPORT OR PRESSURE RISES THESE ARE NOT EXPECTED
TO REACH STRONG WIND CRITERIA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ARCTIC TROUGH OVER THE SOUTHWEST MAINLAND MONDAY NIGHT WILL
BEGIN TO SHIFT EASTWARD OVER SOUTHCENTRAL ALASKA BY TUESDAY...
WHILE A COLD UPPER LOW BEGINS TO TAKE SHAPE OVER THE NORTHERN
GULF. THIS DYNAMIC LOW WILL CONTINUE TO SUPPORT AREAS OF SNOW AND
SNOW SHOWERS INLAND...ESPECIALLY ALONG THE CHUGACH MOUNTAINS INTO
THE COPPER RIVER BASIN. THIS SYSTEM WILL RAPIDLY DEPART
WEDNESDAY...LEAVING BEHIND COLD AIR AND MOUNTAIN SNOW
SHOWERS...ALTHOUGH LOWER ELEVATION SNOW SHOWERS WILL REMAIN ON
WEDNESDAY ACROSS THE COPPER BASIN. A BRIEF REPRIEVE IN WEATHER
WILL LAST ACROSS SOUTHERN ALASKA FROM WEDNESDAY NIGHT THROUGH
THURSDAY AFTERNOON...AS RIDGING OVER THE BERING SEA AND ALEUTIAN
CHAIN SHIFTS EASTWARD OVER THE SOUTHERN MAINLAND BY THURSDAY
MORNING. ANOTHER TROUGH OVER THE FAR WESTERN BERING WILL BEGIN
MOVING A STRONG FRONT ACROSS THE BERING AND INTO SOUTHERN ALASKA
THURSDAY EVENING THROUGH FRIDAY...BRINGING ANOTHER ROUND OF RAIN
AND CLOUDS TO SOUTHERN ALASKA.

MODELS BEGIN TO STRUGGLE MUCH MORE WITH THE OVERALL SHORTWAVE
PATTERN BY THE TRANSITION INTO NEXT WEEKEND. THEY ARE HAVING A
HARD TIME WITH THE TIMING AND STRENGTH OF ANOTHER SYSTEM NEAR THE
SOUTHERN KAMCHATKA PENINSULA...AND ITS ASSOCIATED FRONT TRACKING
INTO THE WESTERN ALEUTIANS/BERING BY THE END OF THE WEEK/EARLY
WEEKEND. HOWEVER...THE FLOW LOOKS TO REMAIN PROGRESSIVE WITH
CHANCES FOR PRECIPITATION LASTING THROUGH THE WEEKEND....AND
TEMPERATURES MODERATING BACK TO NEAR NORMAL BY THE END OF THE
WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 179 180 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CB
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DEK
LONG TERM...TP/JA