Gale Warning 322, NWS Anchorage, AK

805 
FZAK62 PAFC 251200
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 AM AKDT MON APR 25 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.

PKZ499-260130-
400 AM AKDT MON APR 25 2016
.SYNOPSIS FOR CENTRAL BERING SEA...

A 969 MB LOW NEAR 50N 165W MOVES TO 53N 156W AT 985 MB LATE
TONIGHT...THEN MOVES INTO THE SOUTHERN GULF TUE NIGHT. A 980 MB
LOW AT 49N 177W TUE MORNING MOVES TO 50N 174W AT 975 MB LATE TUE
NIGHT.

$$

PKZ411-260130-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
400 AM AKDT MON APR 25 2016

.TODAY...E WIND 15 TO 25 KT. SEAS 10 FT. PATCHY FOG.
.TONIGHT...NE WIND 20 TO 30 KT. SEAS 10 FT. PATCHY FOG.
.TUE...NE WIND 30 KT. SEAS 10 FT. RAIN.
.TUE NIGHT...NE WIND 30 KT. SEAS 11 FT.
.WED THROUGH FRI...N WIND 10 TO 25 KT. SEAS 4 TO 9 FT.

$$

PKZ412-260130-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
400 AM AKDT MON APR 25 2016

.TODAY...NE WIND 25 KT. SEAS 7 TO 10 FT.
.TONIGHT...NE WIND 25 KT. SEAS 8 FT. PATCHY FOG. FREEZING SPRAY N
OF 58N.
.TUE...NE WIND 25 KT. SEAS 6 TO 10 FT.
.TUE NIGHT...NE WIND 20 TO 30 KT. SEAS 5 TO 10 FT.
.WED THROUGH FRI...N WIND 15 TO 30 KT. SEAS 5 TO 10 FT.

$$

PKZ413-260130-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
400 AM AKDT MON APR 25 2016

.TODAY...NE WIND 25 KT. SEAS 10 FT.
.TONIGHT...NE WIND 10 TO 20 KT. SEAS 9 FT.
.TUE...NE WIND 10 TO 25 KT. SEAS 8 FT.
.TUE NIGHT...NE WIND 25 KT. SEAS 8 TO 11 FT.
.WED THROUGH FRI...N WIND 15 TO 30 KT. SEAS 6 TO 11 FT.

$$

PKZ414-260130-
BERING SEA OFFSHORE EAST OF 171W-
400 AM AKDT MON APR 25 2016

...GALE WARNING TODAY...

.TODAY...NE WIND 20 TO 35 KT. SEAS 7 TO 12 FT.
.TONIGHT...NE WIND 15 TO 30 KT. SEAS 7 TO 11 FT.
.TUE...E WIND 15 TO 25 KT. SEAS 7 FT.
.TUE NIGHT...E WIND 25 KT. SEAS 4 TO 8 FT.
.WED THROUGH THU...NE WIND 10 TO 25 KT. SEAS 3 TO 8 FT.
.FRI...N WIND 15 KT. SEAS 4 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
601 AM AKDT SUN APR 24 2016

ANALYSIS AND UPPER LEVELS...

A COMBINATION OF SEVERAL METEOROLOGICAL FACTORS PLAYED A ROLE IN
THE STRONG WINDS SEEN ACROSS TURNAGAIN ARM...HIGHER ELEVATIONS...AND
WEST ANCHORAGE DURING THE DAY TODAY. A FRONT PUSHED THROUGH DURING
THE MID-AFTERNOON HOURS...AIDED BY A STRONG PRESSURE GRADIENT
BETWEEN THE FRONT AND HIGH PRESSURE BUILDING ALONG THE NORTHERN
GULF COAST. THESE TWO FACTORS ALONE WOULD USUALLY KEEP THE STRONG
WINDS OUT OVER THE ARM AND UPPER COOK INLET...WITH FEW POPULATED
AREAS SEEING THE BRUNT OF THE WINDS. HOWEVER...STRONG SUNSHINE
OVER THE AFTERNOON ACROSS THE SUSITNA VALLEY LEAD TO TEMPS IN THE
60S FOR LOCATIONS SUCH AS TALKEETNA. THESE WARM TEMPERATURES
CAUSED A THERMAL LOW TO DEVELOP...THE RESULT OF THE WARM AIR BEING
LESS DENSE AND TENDING TO RISE. WHEN THE WARM AIR RISES...COOLER
AIR MOVES IN TO REPLACE IT...DRAWING IT FROM SURROUNDING AREAS.
THUS...THE TURNAGAIN ARM WINDS TURNED TOWARDS THE NORTH...CAUSING
WIND GUSTS UP TO 35 MPH AT TED STEVENS AIRPORT. A SLACKENING
PRESSURE GRADIENT AND LOSS OF DAYTIME HEATING HAS SINCE HELPED THE
WINDS CALM DOWN.

THE PARENT VERTICALLY-STACKED LOW OF THE AFOREMENTIONED FRONT
REMAINS STATIONARY OVER THE GULF...BUT AS THE NEXT LOW IN THE SET
APPROACHES IT DURING THE DAY TODAY...IT SHOULD DISSIPATE RAPIDLY.
THE UPPER LEVEL LOW THAT HAS BEEN PARKED OVER THE CENTRAL
ALEUTIANS FOR DAYS NOW IS DEVELOPING A NEGATIVE TILT OVER THE
NORTH PACIFIC...IN TURN CAUSING NOTABLY FAST CYCLOGENESIS SOUTH OF
THE EASTERN ALEUTIANS. THIS NEXT LOW WILL BECOME THE PRIMARY
WEATHER MAKER FOR THE ALEUTIANS AND ALASKA PENINSULA OVER THE
COMING DAYS.

FINALLY...A STRONG PRESSURE GRADIENT OVER THE NORTHERN BERING
BETWEEN A POLAR HIGH NORTH OF EASTERN RUSSIA AND THE DEVELOPING
LOW SOUTH OF THE ALEUTIANS ARE KEEPING THE WINDS GUSTY OVER THE
NORTHERN BERING.

&&

.MODEL DISCUSSION...
SYNOPTICALLY...MODELS ARE IN VERY GOOD AGREEMENT IN THE SHORT
TERM. THEY HAD BEEN STRUGGLING RESOLVING SOME ENERGY MOVING FROM
THE COPPER RIVER BASIN TOWARD THE COOK INLET LATER TODAY. BUT THEY
ARE MORE OR LESS ON THE SAME PAGE NOW WITH SOME FAIRLY WIDESPREAD
LIGHT RAIN IN EASTERLY FLOW THROUGHOUT INTERIOR PORTIONS OF SOUTH
CENTRAL. THERE IS ONE OTHER SMALL DISCREPANCY BUT NOTABLE TREND
IN THE MODELS FROM THE PAST FEW DAYS. THE STRONGER LOW DEVELOPING SOUTH
OF DUTCH HARBOR WILL SWING A FRONT INTO THE SOUTHERN GULF LATE
TONIGHT INTO MON. MODELS HAVE TRENDED JUST SLIGHTLY FURTHER SOUTH
AND SLOWER WITH THIS FEATURE. THIS IS VERY SIMILAR IN HOW THEY
HANDLED THE FRONT THAT MOVED THROUGH THE PAST FEW DAYS. THE GFS
WAS PRIMARILY USED IN THIS FORECAST PACKAGE AS IT REPRESENTED A
HAPPY MIDDLE GROUND.

&&

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

AN OCCLUDED FRONT STRETCHING EAST-WEST ACROSS SOUTHCENTRAL
WEAKENS IN PLACE. A FEW WAVES EMBEDDED IN THE LOW/MID LEVEL
EASTERLY FLOW WILL CONTINUE THE POTENTIAL FOR SHOWERS ACROSS
SOUTHCENTRAL THROUGH TODAY. WEAK RIDGING ALONG THE COAST AND LOWER
PRESSURE WITH A WEAK THERMAL TROUGH OVER THE INTERIOR WILL CREATE
LOCALLY GUSTY SOUTHEAST WINDS OVER WESTERN ANCHORAGE AND THE KNIK
RIVER VALLEY WITH SEA BREEZES ALONG THE COASTS THIS AFTERNOON AND
EARLY EVENING.

A WEAKENING LOW OVER THE GULF OF ALASKA LIFTS NORTH TONIGHT AS A TROUGH
AND MOVES OVER THE SOUTHERN INTERIOR MON AFTERNOON. THIS FEATURE
WILL BRING RENEWED SHOWER ACTIVITY ACROSS SOUTHCENTRAL AND STEADY
RAIN ALONG THE COAST TONIGHT. WINDS WILL LIKELY BE ENHANCED ACROSS
TURNAGAIN ARM AND PORTAGE VALLEY. THE NEXT IN A SERIES OF FRONTS
HEADS NORTH ON MON AND WILL BRING WIDESPREAD GALES TO THE GULF
COAST MARINE AREAS WITH BRISK TO STRONG GAP FLOWS ACROSS THE
MAINLAND. PRECIPITATION WILL PREDOMINATELY BE ALONG THE COASTS
AND EAST EXPOSED UPSLOPE AREAS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2...SUN AND MON)...
WEAK OFFSHORE FLOW WILL KEEP MOST PLACES DRY FOR MUCH OF THE DAY.
BUT AS THE STRONGER LOW IN THE NORTH PACIFIC PUSHES A FRONT
NORTHWARD INTO THE GULF OF AK...IT SHOULD PROVIDE ENOUGH ENERGY TO
PUSH A WEAK DISTURBANCE OVER THE ALASKA RANGE OVERNIGHT INTO MON.
THIS WILL BRING THE BEST CHANCE FOR WIDESPREAD RAIN TO THE YK-
DELTA THAT WE HAVE SEEN IN DAYS. AS THE AFOREMENTIONED FRONT
TRACKS NORTH IN THE GULF...IT WILL SERVE TO TIGHTEN THE GRADIENT
OVER THE ALEUTIAN RANGE. THIS WILL BRING A SIGNIFICANT INCREASE TO
THE NORTHEAST TO EAST FLOW THROUGH THAT REGION ON MON. THE BEST
CHANCE FOR PRECIPITATION WITH THIS FRONT WILL BE ON THE WINDWARD
SIDE OF TERRAIN THROUGHOUT SOUTHWEST AS CROSS-BARRIER FLOW SHOULD
KEEP THE LEEWARD SIDE DRY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2...SUN AND
MON)...THE STRONGEST LOW WE HAVE SEEN IN SEVERAL DAYS IS QUICKLY
TRACKING TOWARD DUTCH HARBOR. IT WILL BRING GALE-FORCE EAST TO
NORTHEAST WINDS TO MUCH OF THE CENTRAL ALEUTIANS THROUGH THE DAY.
ON MON...IT WILL WEAKEN AS IT SLOWLY TRACKS OFF TO THE EAST...BUT
WINDS WILL REMAIN GUSTY FROM THE CENTRAL ALEUTIANS TO THE AKPEN.
OVER THE REST OF THE BERING...A FEW WEAK DISTURBANCES WILL
CIRCULATE THROUGH THE LONGWAVE TROUGH IN COUNTER-CLOCKWISE
FASHION. THESE WILL CONTINUE TO BRING BOUTS OF
PRECIPITATION AND SOME SMALL-CRAFT LEVEL WINDS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

BEGINNING THE EXTENDED PERIOD MONDAY EVENING...THERE WILL BE A
LARGE LOW CENTERED SOUTH OF THE ALASKA PENINSULA...WITH RIDGING
OVER THE NORTHWEST BERING SEA. THIS PATTERN WILL SOUND
SIMILAR...AS IT HAS BEEN THE DOMINANT WEATHER PATTERN FOR THE
ENTIRE WINTER AND THE EARLY PART OF THIS SPRING. A WARM FRONT WILL
BE ARCING FROM THE NORTHEAST PACIFIC TO THE NORTHERN GULF
COAST...WITH MOST OF THAT PRECIPITATION IMPACTING THE COAST AND
THE KENAI PENINSULA. DEEP LAYER SOUTHEAST FLOW WILL RESULT IN A
STRONG DOWNSLOPE SHADOW INLAND...WITH MOST SHOWERS AND LIGHT RAIN
OVER SOUTHWEST ALASKA. EVENTUALLY THE LOW WILL WEAKEN AND DRIFT
EAST WITH YET ANOTHER LARGE BERING LOW DEVELOPING OVER THE
ALEUTIANS THEN SLOWLY MOVING EAST...WITH WEAKER BUT FAST MOVING
LOWS MOVING INTO THE GULF OF ALASKA ALONG THE PERIPHERY OF THE
PARENT BERING LOW. THIS WILL KEEP A RATHER CLOUDY REGIME OVER
INLAND SOUTHCENTRAL...WITH MOST SHOWERS REMAINING ALONG THE
MOUNTAINS. TEMPERATURES WILL CONTINUE TO REMAIN ABOVE AVERAGE
HEADING INTO THE WEEKEND WITH NO DRAMATIC PATTERN CHANGE IN SIGHT
THROUGH DAY 7.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 119 120 130 131 132 136 137 138 139 150 155 160 165
170 171 172 173 174 180 351 352 414. SMALL CRAFTS 125 127 129 140
141 175 176 177 178 179 181 185.

&&

SYNOPSIS AND MODEL DISCUSSION...JW/MO
SOUTHCENTRAL ALASKA...BC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MO
LONG TERM...JA