Storm Warning 112, NWS Anchorage, AK

000 
FZAK62 PAFC 202320
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT MON APR 20 2009

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.

PKZ499-211400-
400 PM AKDT MON APR 20 2009
.SYNOPSIS FOR CENTRAL BERING SEA...
A 994 MB LOW NEAR 50N 164E WEAKENS TO 998 MB TUE AFTERNOON NEAR 50N
177E THEN DISSIPATES WED OVER THE CENTRAL ALEUTIANS. MEANWHILE...A
998 MB LOW NEAR 55N 180 DEEPENS TO 986 MB NEAR 57N 173E TUE
AFTERNOON. THE LOW MOVES LITTLE AND WEAKENS SLIGHTLY TO 989 MB NEAR
57N 178E WED AFTERNOON AND MOVES VERY LITTLE THROUGH WED.

$$

PKZ411-211400-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE
400 PM AKDT MON APR 20 2009

.TONIGHT...NW WIND 25 KT. SEAS 10 FT. RAIN AND SNOW. 
.TUE...SW WIND 30 KT. SEAS 10 FT. RAIN AND SNOW. 
.TUE NIGHT...SW WIND 30 KT. SEAS 12 FT. 
.WED...W WIND 30 KT. SEAS 12 FT. 
.WED NIGHT AND THU...W WIND 25 KT. SEAS 10 FT. 
.FRI...E WIND 35 KT. SEAS 10 FT. 
.SAT...SE WIND 25 KT. SEAS 11 FT.  

$$

PKZ412-211400-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N
400 PM AKDT MON APR 20 2009

...GALE WARNING THROUGH TUESDAY...

.TONIGHT...SE WIND 40 KT. SEAS 13 FT. RAIN AND SNOW. 
.TUE...SE WIND 40 KT. SEAS 14 FT. RAIN AND SNOW. 
.TUE NIGHT...S WIND 20 KT. SEAS 11 FT. SNOW.
.WED...S WIND 30 KT. SEAS 12 FT. 
.WED NIGHT...S WIND 25 KT. SEAS 11 FT. 
.THU...SW WIND 25 KT. SEAS 11 FT. 
.FRI...SE WIND 30 KT. SEAS 13 FT. 
.SAT...SE WIND 25 KT. SEAS 13 FT.  

$$

PKZ413-211400-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N
400 PM AKDT MON APR 20 2009

...GALE WARNING THROUGH TUESDAY...

.TONIGHT...S WIND 40 KT. SEAS BUILDING TO 13 FT. RAIN.
.TUE...SW WIND 40 KT DIMINISHING TO 20 KT IN THE AFTERNOON. SEAS
13 FT. RAIN.
.TUE NIGHT...S WIND 25 KT. SEAS 10 FT. 
.WED...S WIND 30 KT. SEAS 11 FT. 
.WED NIGHT AND THU...SW WIND 25 KT. SEAS 12 FT. 
.FRI...S WIND 35 KT. SEAS 15 FT. 
.SAT...S WIND 30 KT. SEAS 14 FT.  

$$

PKZ414-211400-
BERING SEA OFFSHORE EAST OF 171W
400 PM AKDT MON APR 20 2009

...GALE WARNING THROUGH TUESDAY NIGHT...

.TONIGHT...SE WIND 25 KT INCREASING TO 40 KT BY LATE EVENING. SEAS IN
ICE FREE WATERS BUILDING TO 10 FT.
.TUE...SE WIND 45 KT. SEAS IN ICE FREE WATERS 14 FT. RAIN.
.TUE NIGHT...S WIND 35 KT. SEAS IN ICE FREE WATERS 11 FT. RAIN AND
SNOW. 
.WED...S WIND 15 KT. SEAS IN ICE FREE WATERS 7 FT. 
.WED NIGHT...S WIND 25 KT. SEAS IN ICE FREE WATERS 6 FT. 
.THU...SW WIND 25 KT. SEAS IN ICE FREE WATERS 9 FT. 
.FRI...S WIND 35 KT. SEAS IN ICE FREE WATERS 11 FT. 
.SAT...S WIND 30 KT. SEAS IN ICE FREE WATERS 11 FT.  

$$

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
230 PM AKDT SUN APR 19 2009

.MODEL DISCUSSION...MODEL INITIALIZATIONS WERE GOOD AND FORECAST OF
SYNOPTIC FEATURES ARE REASSONABLE AND IN EXCELLENT AGREEMENT THROUGH
WED. THE TREND HAS BEEN TO SLOW DOWN THE ONSET OF SW FLOW AND
MOISTURE ADVECTION INTO SOUTHCENTRAL. AFTERNOON PACKAGES WILL BE
BASED ON A BLEND THE THE NAM AND GFS IN THE EAST AND SOME SLIGHT
ADJUSTMENT WITH THE GFS IN THE WEST.

.UPPER LEVELS...
500 MB...THE OMEGA BLOCKING PATTERN SHIFTS EAST THROUGH THIS WEEK.
THE CUT-OFF LOW OVER THE GULF MOVES EAST INTO CANADA AS A HIGH
AMPLITUDE RIDGE BUILDS OVER THE WESTERN GULF AND THE MAINLAND TUE
NIGHT. THE RIDGE AXIS MOVES EAST TO OVER THE WEST/CENTRAL GULF AND
WESTERN CANADA THU AFTERNOON AND SETS UP SOUTHWESTERLY FLOW OVER THE
MAINLAND. FURTHER WEST...THE LOW NEAR KAMCHATKA MOVES INTO THE NORTH
CENTRAL BERING SEA THU AND INTENSIFIES.

.SHORT TERM FORECAST...

.EAST...SHORT WAVE OVER THE WESTERN GULF/SOUTHCENTRAL ALASKA WILL
WEAKEN AS IT SHIFTS WEST TONIGHT. THE GENERAL LOW COMPLEX OVER THE
GULF OF ALASKA WILL MOVE EAST AS HIGH PRESSURE BUILDS OVER THE GULF
AND MAINLAND TUE.  A WEAK INVERTED TROUGH WILL LIKELY OVER ALONG THE
NORTHERN GULF THROUGH TUE...BUT SHOULD WEAKEN WED AS HIGH PRESSURE
TAKES HOLD. UNSTABLE CONDITIONS ARE LIKELY OVER THE EASTERN COPPER
RIVER BASIN MON AND TUE AS A WEAK THERMAL TROUGH SETS OVER THE AREA.
OTHERWISE...GENERALLY WARMER AND DRIER WEATHER IN STORE FOR MUCH OF
EASTERN ZONES THROUGH THE MIDDLE OF THIS WEEK. SHOULD SEE INCREASING
CLOUDS WITH A CHANCE OF PRECIPITATION INTO SOUTHCENTRAL ON THU AS
FRONTAL TROUGH APPROACHES.

.WEST...
SHORT WAVE MOVING THROUGH SW ALASKA THIS AFTERNOON IS SHOWING SIGNS
OF WEAKENING WITH WARMING CLOUD TOPS AND GREATLY REDUCED RADAR
RETURNS. SUBSIDENCE ON THE BACKSIDE OF TROUGH PRODUCED FOG OVER
EASTERN BRISTOL BAY THIS MORNING. ABUNDANT LOW LEVEL MOISTURE AND A
BUILDING RIDGE TONIGHT WILL LIKELY PRODUCE WIDESPREAD FLOW OVER
BRISTOL BAY TONIGHT...AS WILL AS PORTIONS OF THE DELTA. LOW CENTER
NEAR KAMCHATKA WILL SLOWLY WEAKEN AND SHIFT WEST. FRONTAL TROUGH OVER
THE WESTERN ALEUTIANS THIS MORNING WILL MOVE JUST EAST OF THE
DATELINE EARLY MON. A SECONDARY LOW DEVELOPS ALONG THE FRONT MON AND
INTENSIFIES AS IT MOVES TO THE NORTH CENTRAL BERING SEA TUE
AFTERNOON. THE ASSOCIATED FRONT WHICH SLOWS SOME MON WITH DEVELOPING
LOW...MOVES TO THE AK PEN AND AND DELTA/WESTERN BRISTOL BAY BY EARLY
WED MORNING. EXPECT SOUTHERLY GALES WITH AND IN ADVANCE OF FRONTAL
SYSTEM. THE AIR IN ADVANCE OF THE FRONTAL TROUGH WILL BE WARM ENOUGH
THAT PRECIPITATION WILL BE A MIX OR RAIN AND SNOW. FRONT WEAKENS AS
IT MOVES INLAND WED AND THU. BROAD SOUTHWESTERLY FLOW SETS UP OVER
MUCH OF THE BERING SEA AND SW ALASKA THU WITH CENTRAL NEUTRAL
TEMPERATURE ADVECTION.

.LONG TERM FORECAST...A PATTERN CHANGE IS UNDERWAY STARTING TODAY FOR
MAINLAND ALASKA AND THE BERING SEA. AS THE RIDGE MOVES EAST TO BE
CENTERED OVER MAINLAND ALASKA BY MIDWEEK IT WILL BE REPLACED BY MOIST
SOUTHERLY FLOW THAT WILL SPREAD ABUNDANT MOISTURE TO THE BERING AND
MOST OF MAINLAND ALASKA. IN GENERAL...AN UNSEASONABLY CLEAR AND WARM
START TO THE WEEK WILL DETERIORATE TO COOLER AND MUCH WETTER
CONDITIONS BY THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...170 172 179
FIRE WEATHER...NONE.

RMC APR 09