Small Craft Advisory 277, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
443 AM AKDT SUN MAR 29 2015

.ANALYSIS AND UPPER LEVELS...
THE BROAD COMPLEX LOW WHICH HAS BEEN OVER THE ALASKA PENINSULA FOR
THE PAST SEVERAL DAYS HAS SHIFTED SLIGHTLY EASTWARD TO A MEAN
POSITION SOUTH OF KODIAK ISLAND THIS MORNING AS A 982 MB SURFACE
LOW MOVES INTO THE WESTERN GULF. AN ASSOCIATED FRONT OUT AHEAD OF
THIS LOW IS SPREADING A MIX OF RAIN AND SNOW OVER THE GULF COAST
AND A SWATH OF GALE FORCE WINDS ACROSS THE NORTHERN GULF. INLAND
LOCATIONS REMAIN MOSTLY DRY AS A RESULT OF STRONG CROSS BARRIER
FLOW OVER THE CHUGACH AND TALKEETNA MOUNTAINS. OUT WEST...A
SERIES OF UPPER LEVEL WAVES MOVING WESTWARD ACROSS THE EASTERN
BERING ARE GENERATING RAIN SHOWERS FROM DUTCH HARBOR TO COLD BAY
WHILE A FRONT OVER THE WESTERN BERING IS BRINGING LIGHT SNOW TO
THE WESTERN ALEUTIANS.

&&

.MODEL DISCUSSION...
MODELS ARE IN GENERALLY GOOD SHORT TERM AGREEMENT AS THE BROAD
UPPER LOW SOUTH OF KODIAK MOVES TOWARDS THE CENTRAL GULF AND
GRADUALLY WEAKENS THROUGH THE MIDDLE OF THE WEEK. THE NAM IS A
BIT OF A SLOW OUTLIER WITH ANOTHER LOW SET TO BRUSH THE SOUTH
SIDE OF THE ALEUTIAN CHAIN EARLY IN THE WEEK WHEREAS THE EC/GEM
SOLUTIONS HAVE BEEN ON THE SLIGHTLY FASTER END OF THE SPECTRUM.
THEREFORE MAINLY USED THE GFS AS A MIDDLE GROUND SOLUTION FOR THE
MORNING PACKAGE.

&&

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

BIGGEST CHANGE FROM YESTERDAY IS THAT AN UPPER LEVEL WAVE IN THE
NORTHEAST GULF BECAME STRONGER THAN EXPECTED AND HAS BROUGHT MORE
WINDS AND RAINFALL TO THE NORTHERN GULF THIS MORNING. THIS WAVE
WILL WEAKEN THROUGH THE DAY AND AREAS ON THE LEEWARD SIDE OF THE
MOUNTAINS WILL STILL SEE VERY LITTLE IF ANY PRECIPITATION...MOST
OF WHICH WILL FALL AS RAIN AS TEMPERATURES REMAIN ABOVE NORMAL
OVER THE REGION. THIS PATTERN WILL PERSIST THROUGH THE EARLY PART
OF THE WEEK.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
LOW PRESSURE SOUTH OF THE ALASKA PENINSULA CONTINUES TO BRING
CLOUD COVER AND SHOWERS TO AREAS AROUND BRISTOL BAY. THIS LOW IS
ALSO BRINGING NORTHEASTERLY FLOW TO THE SOUTHWEST WHICH IS HELPING
TO DRY OUT AREAS AROUND THE KUSKOKWIM DELTA. HOWEVER...ON MONDAY
THE LOW WILL BRING ANOTHER WAVE OVER THE SOUTHWEST WHICH WILL HELP
TO BRING BACK PRECIP TO MORE WIDESPREAD AREAS AROUND THE
SOUTHWEST.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT IS TRACKING EAST ACROSS THE WESTERN ALEUTIANS BRINGING
SNOW TO THOSE AREAS. BY THIS EVENING IT WILL HAVE MADE ITS WAY TO
THE CENTRAL ALEUTIANS BUT WILL THEN DISSIPATE. ANOTHER STRONGER
SYSTEM WILL MOVE INTO THE AREA MONDAY AND RAPIDLY TRACK EAST WHILE
STAYING SOUTH OF THE ALEUTIANS. FOR THE BERING...NORTHERLY FLOW
WILL CONTINUE FOR THE NEXT COUPLE DAYS LEADING TO A SHOWERY REGIME
THROUGHOUT MUCH OF THE AREA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PATTERN SHIFT BEGINS TUESDAY INTO WEDNESDAY WITH AN UPPER RIDGE
BUILDING INTO THE BERING BEHIND LOW PRESSURE OVER THE GULF OF
ALASKA. AT THE SURFACE...A LOW PRESSURE CENTER PUSHES A WARM FRONT
QUICKLY ACROSS THE ALEUTIAN CHAIN WITH AN ARCTIC AIR MASS ADVECTING
IN BEHIND THE FRONT BY TUESDAY AFTERNOON. PRECIPITATION WILL
MAINLY BE RAIN ALONG THE FRONT CHANGING OVER TO SNOW SHOWERS
BEHIND THE SYSTEM. THIS COLD AIR WRAPS INTO LOW PRESSURE AS IT
MOVES ACROSS WESTERN GULF ON WEDNESDAY. THERE IS STILL UNCERTAINTY
IN THE MODELS FOR THE SECOND HALF OF THE WEEK AS THIS LOW TRACKS
EAST...HOWEVER THE PATTERN ACROSS THE GULF CONTINUES TO KEEP MOST
OF THE PRECIPITATION ACROSS THE GULF AND ALONG THE COAST. THIS
STORM SYSTEM WILL BE WORTH WATCHING AS GUSTY SOUTHERLY WINDS
ACROSS THE SOUTHERN MAINLAND AND THE GULF BECOME NORTHERLY AS IT
MOVES EAST. FRIDAY NIGHT A SUBTROPICAL SYSTEM BEGINS TO DEVELOP
BRINGING THE NEXT WARM FRONT INTO THE ALEUTIANS AND SOUTHERN
BERING FOR THE BEGINNING OF THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CB
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...KH