Gale Warning 318, NWS Anchorage, AK

216 
FZAK62 PAFC 192302
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
302 PM AKDT TUE APR 19 2016

OFFSHORE WATERS FORECAST FOR THE BERING SEA

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.

PKZ499-201415-
302 PM AKDT TUE APR 19 2016
.SYNOPSIS FOR CENTRAL BERING SEA...
A FRONT FROM THE CENTRAL BERING THROUGH THE EASTERN ALEUTIANS
REMAINS IN PLACE THROUGH WED MORNING. A 986 MB LOW DEVELOPS ALONG
THIS FRONT NEAR 54N 166W WED MORNING AND MOVES TO 58N 177E AT 993
MB THU AFTERNOON. A 990 MB NORTH PACIFIC LOW MOVES TO 55N 165W
THU AFTERNOON.

$$

PKZ411-201415-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
302 PM AKDT TUE APR 19 2016

.TONIGHT...NE WIND 10 TO 20 KT...EXCEPT VARIABLE 10 KT S OF 56N. 
SEAS 6 FT.
.WED...NE WIND 10 TO 20 KT...EXCEPT VARIABLE 10 KT S OF 56N. 
SEAS 7 FT.
.WED NIGHT...NE WIND 10 TO 20 KT...EXCEPT VARIABLE 10 KT S OF 56N
AND E OF 177E. SEAS 7 FT.
.THU...VARIABLE WIND UP TO 15 KT. SEAS 6 FT.
.THU NIGHT...NE WIND UP TO 15 KT. SEAS 6 FT.
.FRI THROUGH SUN...NE WIND 15 TO 30 KT. SEAS 5 TO 10 FT.

$$

PKZ412-201415-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
302 PM AKDT TUE APR 19 2016

.TONIGHT...E WIND 10 TO 20 KT. SEAS 5 FT.
.WED...E WIND 10 TO 25 KT...STRONGEST IN THE AFTERNOON E OF 174W.
SEAS 5 FT.
.WED NIGHT...E WIND 10 TO 25 KT...EXCEPT VARIABLE WIND 10 KT S OF
57N. SEAS 5 TO 8 FT.
.THU...E WIND 10 TO 25 KT. SEAS 5 TO 8 FT.
.THU NIGHT...NE WIND 10 TO 25 KT. SEAS 4 TO 7 FT.
.FRI THROUGH SUN...NE WIND 15 TO 30 KT. SEAS 4 TO 9 FT.

$$

PKZ413-201415-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
302 PM AKDT TUE APR 19 2016

.TONIGHT...NE WIND 10 TO 15 KT BECOMING VARIABLE UP TO 15 KT 
AFTER MIDNIGHT. SEAS 5 FT.
.WED...VARIABLE WIND UP TO 10 KT...EXCEPT BECOMING NW WIND 
10 TO 15 KT IN THE AFTERNOON E OF 175W. SEAS 5 FT.
.WED NIGHT...W WIND 10 TO 15 KT. SEAS 6 FT.
.THU...VARIABLE WIND UP TO 15 KT. SEAS 6 FT.
.THU NIGHT...NW WIND UP TO 15 KT. SEAS 5 FT.
.FRI...NW WIND UP TO 15 KT. SEAS 4 TO 7 FT.
.SAT THROUGH SUN...N WIND 15 TO 25 KT. SEAS 5 TO 8 FT.

$$

PKZ414-201415-
BERING SEA OFFSHORE EAST OF 171W-
302 PM AKDT TUE APR 19 2016

.TONIGHT...E WIND 15 TO 25 KT. SEAS 6 FT.
.WED...E WIND 15 TO 30 KT. SEAS 6 TO 11 FT. RAIN.
.WED NIGHT...SE WIND 15 TO 30 KT...EXCEPT W 10 KT S OF 56N. 
SEAS 7 TO 12 FT. RAIN MAINLY N OF 56N.
.THU...E WIND 15 TO 30 KT. SEAS 5 TO 9 FT.
.THU NIGHT...E WIND 15 TO 30 KT. SEAS 6 TO 11 FT.
.FRI THROUGH SUN...NE WIND 10 TO 25 KT. SEAS 4 TO 9 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT MON APR 18 2016

.ANALYSIS AND UPPER LEVELS...
A CLOSED LOW OVER THE CENTRAL ALEUTIANS THIS MORNING IS SEPARATED
FROM A LONGWAVE TROUGH OVER THE EASTERN MAINLAND BY A SHORTWAVE
RIDGE. AT THE SURFACE A COMPLEX LOW PRESSURE SYSTEM REMAINS IN THE
CENTRAL BERING WITH A WEAKENING WEATHER FRONT EXTENDING THROUGH
THE ALASKA PENINSULA AND APPROACHING THE WEST COAST. WINDS ALONG
THIS FRONT ARE GUSTY ALTHOUGH NOT REACHING WARNING LEVEL. THEY
WILL CONTINUE TO BE GUSTY AS THE FRONT MOVES ONSHORE THROUGH
TUESDAY. SOUTHERLY FLOW ON THE EAST SIDE OF THE BERING LOW
CONTINUES TO BRING WARM AIR INTO SOUTHCENTRAL AND SOUTHWESTERN
ALASKA. WARM TEMPERATURES AND SUNNY SKIES HAVE BEEN PREDOMINANT
OUTSIDE OF THE BERING SEA BUT THIS TREND WILL DIMINISH SLIGHTLY
WITH THE APPROACH OF THE BERING SEA FRONT.

OVER THE MAINLAND A LINGERING WEAK LOW IN THE GULF OF ALASKA HAS
CAUSED UNSTABLE CONDITIONS OVER THE PAST FEW DAYS. AFTERNOON
SHOWERS POPPING UP OVER THE MOUNTAINS HAVE LOOKED DRAMATIC BUT
PRODUCED NO LIGHTNING STRIKES AND MINIMAL PRECIPITATION. AS THE
SHORTWAVE RIDGE MOVES IN OVERHEAD CONDITIONS SHOULD STABILIZE AND
SHOWERS WILL BECOME EVEN SPARSER AND LESS EXCITING TODAY AND INTO
TOMORROW. AS FOR WINDS...OUTSIDE OF SHOWERS FOR THE PAST FEW DAYS
WINDS HAVE BEEN LIGHT OVER THE MAINLAND.

&&

.MODEL DISCUSSION...
MODELS WERE IN PRETTY GOOD AGREEMENT TODAY. THERE WAS SOME SLIGHT
DIFFERENTIATION IN THE NAM SOLUTION ON HOW QUICKLY IT MOVED THE
LOW PRESSURE SYSTEMS ACROSS THE BERING BUT OVERALL THIS WAS NOT
ENOUGH TO MAKE A LARGE DIFFERENCE IN THE FORECAST. EC/GFS BLEND
WAS USED OUT WEST FOR LOW PLACEMENT WITH NAM INFLUENCES FOR
CHANNELED TERRAIN AND PRIMARILY THE NAM WAS USED IN THE EAST TO
CAPTURE LOCAL EFFECTS.

&&

.FIRE WEATHER...
THE MAIN CONCERN FOR FIRE WEATHER AT THIS POINT IS GUSTY WINDS IN
BOTH THE EAST AND THE WEST. WINDS WILL INCREASE ALONG THE FRONT
APPROACHING FROM THE BERING AND THROUGH CHANNELED TERRAIN AHEAD OF
THE FRONT. PRECIPITATION IS EXPECTED ALONG THE FRONT...ALTHOUGH
WITH SOUTHEASTERLY FLOW DOWNSLOPING ALONG THE WESTERN SIDES OF
RANGES WILL CONTINUE AND CHANCE OF WETTING RAINS IN THESE AREAS
WILL DROP SIGNIFICANTLY. ALTHOUGH RH VALUES WILL REMAIN ABOVE RED
FLAG CRITERIA...THE WINDS COULD BE PROBLEMATIC FOR ANY FIRE
STARTS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

MOSTLY CLEAR SKIES HAVE PREVAILED ACROSS MUCH OF SOUTHCENTRAL
ALASKA DURING THE DAY TODAY BUT RECENT SATELLITE OBSERVATIONS
SHOW SOME DIURNAL CONVECTION POPPING UP ACROSS THE MATANUSKA AND
SUSITNA VALLEYS. THESE CONVECTIVE SHOWERS WILL ULTIMATELY HAVE
LESS COVERAGE TODAY WHEN COMPARED TO THE PREVIOUS 2-3 DAYS LARGELY
BECAUSE LAPSE RATES FROM 850 MB TO 500 MB LOOKS VERY WEAK COMPARED
TO PREVIOUS DAYS. SHOWER ACTIVITY SHOULD BE SUPPRESSED ACROSS THE
SOUTHCENTRAL MAINLAND TOMORROW AND WEDNESDAY AS A BUILDING RIDGE
PRODUCES A STRONG CAPPING INVERSION (SUBSIDENCE). GUSTY WINDS WILL
BEGIN TO DEVELOP THIS AFTERNOON ACROSS TURNAGAIN ARM...PORTAGE
VALLEY...THE KNIK RIVER VALLEY AND THE COPPER RIVER AS DECENT
PRESSURE RISES ASSOCIATED WITH BUILDING RIDGE. GUSTY WINDS WILL BE
OBSERVED IN ANCHORAGE AS THE GRADIENT OVER COOK INLET REMAINS
WEAKLY UP-INLET WHICH WILL ALLOW THE TURNAGAIN ARM WINDS TO RE-
CURVE INTO TOWN. THE GUSTY WINDS AT ALL AFOREMENTIONED LOCATIONS
WILL CONTINUE THROUGH WEDNESDAY AFTERNOON WITH THE WINDS PEAKING
LATE TUESDAY NIGHT/WEDNESDAY MORNING.

IN THE MEAN TIME...A FRONTAL OCCLUSION WILL BEGIN TO ENTER THE FAR
WESTERN GULF OF ALASKA TONIGHT. THIS WILL BRING RAIN CHANCES BACK
TO KODIAK ISLAND AND THEN TO THE WESTERN KENAI AND PRINCE WILLIAM
SOUND BY TUESDAY MORNING. MUCH OF INTERIOR SOUTHCENTRAL ALASKA
WILL REMAIN ON THE DRY SIDE AS DOWNSLOPING WINDS SHOULD PREVAIL.
THE FRONT WILL THEN DISSIPATE/RETROGRADE WEDNESDAY AFTERNOON AS
THE RIDGE OVER SOUTHCENTRAL ALASKA BUILDS AND FORCES IT WESTWARD
TOWARD THE ALASKA PENINSULA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE WEAKENING FRONT JUST OFF THE SOUTHWEST MAINLAND COAST WILL
PUSH INLAND TONIGHT BEFORE STALLING AGAIN TUESDAY INTO TUESDAY
NIGHT WHILE GRADUALLY DISSIPATING. IN THE MEANTIME...A NEW FRONT
WILL STRENGTHEN OVER THE CENTRAL AND EASTERN BERING TUESDAY NIGHT
INTO WEDNESDAY. THE RESULT WILL BE WET AND WINDY
CONDITIONS...ESPECIALLY TOWARD BRISTOL BAY AND THE SOUTHERN
KUSKOKWIM DELTA COAST...THROUGH THE NEXT COUPLE OF DAYS. ENOUGH
LOW-LEVEL INSTABILITY EXISTS TO ALLOW FOR THE THE STRATIFORM RAIN
CONDITIONS OVER SOUTHWEST TO BECOME MORE SHOWERY IN THE LATE
AFTERNOON AND EARLY EVENING HOURS...BUT NO THUNDERSTORM ACTIVITY
IS ANTICIPATED.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
BROAD AND COMPLEX LOW PRESSURE ENCOMPASSING THE SOUTHWESTERN
QUADRANT OF THE BERING SEA WILL REMAIN LARGELY STATIONARY THROUGH
TUESDAY. A JET STREAK SLIDES QUICKLY TO THE SOUTH OF THE
ALEUTIANS TUESDAY...AND AS IT REACHES SOUTH OF THE EASTERN
ALEUTIANS LATE TUESDAY NIGHT WILL HELP TO DEVELOP A WEAK TRIPLE
POINT LOW IN THE VICINITY OF UNALASKA/DUTCH HARBOR BY WEDNESDAY
MORNING. THIS SYSTEM AND ITS ASSOCIATED RAIN AND SMALL CRAFT
ADVISORY-LEVEL WINDS WILL MOVE NORTHWEST THROUGH THE CENTRAL AND
EASTERN BERING SEA THROUGH DURING THE DAY ON WEDNESDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE WEAK LOW PRESSURE SYSTEM LOCATED OVER THE WESTERN ALEUTAINS
CONTINUES TO PHASE IN WITH A 500 MB CLOSED LOW OVER THE CENTRAL
BERING SEA. THIS SYNOPTIC FEATURE HAS AN ASSOCIATED TROUGH
EXTENDING THROUGH THE EASTERN ALEUTIANS INTO THE NORTH PACIFIC.
THE AFOREMENTIONED SYNOPTIC FEATURES WILL TRANSITION INTO A BROAD
AREA OF LOW PRESSURE REFLECTED AT THE SURFACE OVER THE CENTRAL TO
EASTERN ALEUTIAN CHAIN HEADING INTO THE WEEKEND. THIS WILL PRODUCE
A SHOWERY WEATHER REGIME FOR THE BERING AND THE ALEUTIAN CHAIN.
WHILE THE SOUTHWESTERN COASTLINE WILL HAVE SOME SHOWERY
PRECIPITATION THROUGH THE WEEK WITH WEAK DISTURBANCES MOVING
THROUGH THE REGION. THE SOUTHCENTRAL WILL BE UNDER THE INFLUENCE
OF NEGATIVE TILTED RIDGE THAT WILL BUILD OVER THE SOUTHEAST
PANHANDLE EXTENDING TO THE NORTHWEST INTO THE ALASKA RANGE. WHILE
THE GULF WILL HAVE UPPER LEVEL CLOSED LOWS THAT WILL ROTATE AROUND
IN THE BASE OF THE LONGWAVE TROUGH LOCATED THROUGH THE GULF. THIS
WILL SEND SHORTWAVES THROUGH THE GULF RESULTING IN MAJORITY OF THE
PRECIPITATION OCCURRING ALONG THE NORTHERN GULF AND THE COASTAL
COMMUNITIES. THE ANCHORAGE BOWL AND WESTERN KENAI PENINSULA WILL
RECEIVE DRIER CONDITIONS DUE TO THE CROSS-BARRIER FLOW HEADING
INTO THE WEEKEND. WITH A LARGE UPPER LEVEL LOW CENTERED OVER THE
WESTERN ALEUTIANS AND ANOTHER SURFACE LOW SOUTH OF THE ALEUTIANS
SPINNING UP TOWARDS THE ALASKA PENINSULA FRIDAY. BY SATURDAY THE
MEAN UPPER LOW POSITION WILL SHIFT TO THE CENTRAL ALEUTIANS WITH
SEVERAL ADDITIONAL FRONTAL SYSTEMS ROTATING ACROSS THE ALASKA
PENINSULA AND THEN PROGRESSIVELY FURTHER EAST INTO THE GULF
THROUGH EARLY NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 130 131 155 160 180.

&&

SYNOPSIS AND MODEL DISCUSSION...LF
SOUTHCENTRAL ALASKA...MC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...PD