High Wind Watch 15, NWS Anchorage, AK

345 
WWAK72 PAFC 190020
NPWALU

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
420 PM AKDT FRI MAR 18 2011


AKZ181-191330-
/X.UPG.PAFC.HW.A.0015.110320T0000Z-110320T1200Z/
/X.NEW.PAFC.HW.W.0022.110319T2100Z-110320T1300Z/
ALASKA PENINSULA-
INCLUDING THE CITIES OF...COLD BAY...SAND POINT
420 PM AKDT FRI MAR 18 2011

...HIGH WIND WARNING IN EFFECT FROM 1 PM SATURDAY TO 5 AM AKDT
SUNDAY...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED A HIGH WIND
WARNING...WHICH IS IN EFFECT FROM 1 PM SATURDAY TO 5 AM AKDT
SUNDAY. THE HIGH WIND WATCH IS NO LONGER IN EFFECT. 

A FAST-MOVING LOW PRESSURE SYSTEM WILL MOVE NORTH ACROSS THE
EASTERN ALEUTIANS SATURDAY AND THROUGH THE EASTERN BERING
SATURDAY NIGHT. SOUTHEAST WINDS WILL INCREASE TO 45 TO 65 MPH
SATURDAY AFTERNOON...WITH LOCAL GUSTS TO 85 MPH ESPECIALLY
THROUGH CHANNELED TERRAIN.

WINDS WILL VEER TO SOUTHWESTERLY AND SLOWLY BEGIN TO DIMINISH
SUNDAY MORNING.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
OR OCCURRING. PEOPLE ARE URGED TO SECURE LOOSE OBJECTS THAT COULD
BE BLOWN AROUND OR DAMAGED BY THE WIND.

&&

$$

AKZ185-191330-
/X.NEW.PAFC.HW.W.0022.110319T1800Z-110320T1300Z/
EASTERN ALEUTIANS-
INCLUDING THE CITIES OF...UNALASKA...NIKOLSKI
420 PM AKDT FRI MAR 18 2011

...HIGH WIND WARNING IN EFFECT FROM 10 AM SATURDAY TO 5 AM AKDT
SUNDAY...

THE NATIONAL WEATHER SERVICE IN ANCHORAGE HAS ISSUED A HIGH WIND
WARNING...WHICH IS IN EFFECT FROM 10 AM SATURDAY TO 5 AM AKDT
SUNDAY. 

A FAST-MOVING LOW PRESSURE SYSTEM WILL MOVE NORTH ACROSS THE
EASTERN ALEUTIANS SATURDAY AND THROUGH THE EASTERN BERING SATURDAY
NIGHT. SOUTHEAST WINDS WILL INCREASE TO 45 TO 65 MPH SATURDAY
AFTERNOON...WITH LOCAL GUSTS TO 85 MPH ESPECIALLY THROUGH
CHANNELED TERRAIN FROM UNALASKA ISLAND EAST.

WINDS WILL VEER TO SOUTHWESTERLY AND THEN WESTERLY BEGINNING EARLY
SATURDAY EVENING. WIND SPEEDS OF 50 TO 65 MPH WITH GUSTS TO 80 MPH
WILL CONTINUE THROUGH EARLY SUNDAY MORNING...BEFORE GRADUALLY
DIMINISHING DURING THE DAY ON SUNDAY AS THE LOW MOVES MOVES AWAY
FROM THE REGION.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
OR OCCURRING. PEOPLE ARE URGED TO SECURE LOOSE OBJECTS THAT COULD
BE BLOWN AROUND OR DAMAGED BY THE WIND.

&&

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT THU MAR 17 2011

.MODEL DISCUSSION...MODELS ARE IN GOOD AGREEMENT ON THE CURRENT
WEATHER FEATURES INCLUDING THE VERY LARGE LOW IN THE WESTERN BERING.
THE FEATURE THAT HAS BEEN GIVING MODELS FITS IS A TRIPLE POINT LOW
DEVELOPING OFF THIS MAIN LOW THAT WILL MOVE INTO THE VICINITY OF THE
EASTERN ALEUTIANS AND ALASKA PENINSULA ON SATURDAY. THERE HAVE BEEN
VERY LARGE DIFFERENCES IN THE SOLUTIONS WITH THIS LOW. AT THIS TIME
THE THINKING IS THAT THE GFS HAS THE BEST SOLUTION FOR IT AS THE
ECMWF HAS BEEN IN CATCH UP MODE COMPARED TO THE GFS. THE MAIN IMPACT
IS THAT THE GFS SOLUTION HAS A FASTER AND DEEPER LOW THAN THE OTHER
MODELS.

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL PATTERN HAS A HIGH
AMPLITUDE RIDGE OVER THE EASTERN BERING SEA AND WESTERN ALASKA COAST
WITH A STRONG UPPER LEVEL LOW IN THE WESTERN BERING SEA AND WEAKER
UPPER LEVEL LOW IN THE SOUTHEAST GULF. WHEN ONE LOOKS AT THE SURFACE
MAP OR A SATELLITE IMAGE THE FEATURE THAT JUMPS OUT THE MOST IS THE
LARGE LOW APPROACHING ATTU THAT IS IN THE MID 930S MB. THIS POWERFUL
LOW WILL REMAIN IN THE WESTERN BERING SEA AND WEAKEN AS IT MOVES INTO
EASTERN RUSSIA FRI NIGHT. THE STRONG FRONT ASSOCIATED WITH THIS LOW
IS IN THE CENTRAL BERING SEA AND WEAKENING AS IT RUNS INTO THE RIDGE.

THE WEATHER MAKING FEATURES IN THE EASTERN PART OF THE FORECAST AREA
ARE A BIT MORE SUBTLE WITH A SHORT WAVE MOVING SOUTHEAST ACROSS THE
COPPER RIVER BASIN AND A WEAK INVERTED TROUGH OVER COOK INLET.

.SHORT TERM FORECAST...THE BERING SEA IS FAIRLY STRAIGHTFORWARD WITH
A LARGE LOW BRINGING STRONG WINDS AND PRECIPITATION INTO THE BERING
SEA AND ALEUTIAN ISLANDS AREAS. IT GETS A LITTLE MORE UNCERTAIN IN
THIS AREA SATURDAY AS A LOW WILL MOVE INTO THE EASTERN BERING SEA.
THIS IS LIKELY TO BE A STRONG LOW THAT COULD PRODUCE STORM FORCE
WINDS BUT THE UNCERTAINTY IN THE ACTUAL STRENGTH AND TRACK MAKE IT A
SYSTEM THAT WARRANTS CLOSE WATCHING.
THE EASTERN SECTION OF THE AREA...ESPECIALLY THE COOK INLET REGION IS
MORE COMPLEX SINCE SOME VERY SUBTLE FEATURES ARE CREATING SIGNIFICANT
WEATHER DIFFERENCES. THE NORTHWEST PART OF THE SUSITNA VALLEY IS
SITTING IN SUNSHINE THIS AFTERNOON WHILE THERE IS SNOW SOUTHEAST OF
TALKEETNA...AND THE LINE BETWEEN THE TWO IS QUITE SHARP. THIS
DEFORMATION AREA BRINGING THE SNOW TO THE AREA IS OSCILLATING A BIT
AS IT SLOWLY WRINGS THE MOISTURE OUT OF THE ATMOSPHERE AND WEAKENS.
THIS ALSO BRINGS UP THE QUESTION ABOUT AREAS OF FOG AND OR STRATUS
OVER ANCHORAGE AND COOK INLET AS WELL AS TH SUSITNA VALLEY AS THIS
SYSTEM DISSIPATES OVERHEAD. SUPPORTING THE POSSIBILITY OF LOW CLOUDS
IS THE UPPER LEVEL LOW MOVING DIRECTLY OVER THE AREA. THIS CAN CAUSE
THE GRADIENT TO STAGNATE AND THE DOWNWARD VERTICAL MOTION CAN SUPPORT
LOW CLOUDS AND FOG. ON THE OTHER HAND THERE IS SIGNIFICANT CLEARING
IN THE NORTHWEST SUSITNA VALLEY AND AREAS WESTWARD THAT MIGHT SIGNAL
THE ATMOSPHERE IS NOT AS CONDUCIVE TO STRATUS AND FOG DEVELOPMENT.
THE COPPER RIVER BASIN IS IN A SIMILAR SITUATION WHERE THE SNOW TODAY
MIGHT TRIGGER THE DEVELOPMENT OF FOG AND STRATUS AFTER THE
PRECIPITATION STOPS.

.LONG TERM FORECAST...AFTER THE LOW PASSES THROUGH THE EASTERN BERING
SEA SATURDAY INTO SUNDAY THE OVERALL PATTERN WILL BECOME MORE
PROGRESSIVE WHICH WILL MEAN A RETURN TO MORE UNSETTLED WEATHER OVER
THE REGION. TEMPERATURES SHOULD REMAIN SEASONAL THROUGH THE WEEK NEXT
WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 155 165 170 172 176 179 180.
         STORM 175 180.
FIRE WEATHER...NONE.

MAR 11