Small Craft Advisory 236, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
142 PM AKDT WED MAR 19 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER-LVL RIDGE CONTINUES TO BUILD NORTHEASTWARD THROUGH THE
WESTERN MAINLAND WITH AN UPPER-HIGH CENTER FORMING NEAR NUNIVAK
ISLAND. A BROAD AND WEAK UPPER-LOW MEANDERS IN THE NE GULF OF AK
AND IS NEARLY STATIONARY. MUCH OF THE SOUTH CENTRAL AND SOUTHWEST
MAINLAND IS LOCKED INTO A FAIRLY DRY WEATHER PATTERN WITH MINIMAL
CLOUDINESS IN BETWEEN THESE TWO DOMINANT FEATURES. OFF-SHORE GAP
WINDS PERSIST IN EARNEST ACROSS THE TYPICAL AREAS OF THE KENAI
PENINSULA AND PRINCE WILLIAM SOUND. AREAS WITH APPRECIABLE
TRANSPORTABLE LIKE THOMPSON PASS ARE STILL SEEING SOME REDUCED
VISIBILITY IN BLOWING SNOW. FURTHER WEST...A PACIFIC LOW CENTERED 200
MILES S OF UNALASKA IS MOVING EAST. THE ASSOCIATED FRONT IS
STALLING AND ELONGATING OVER THE SOUTHERN BERING SEA AND AKPEN.
MOST OF THE STEADIER PRECIPITATION FALLS OVER THE EASTERN CHAIN
AND AKPEN WITH A FEW PERIPHERAL FLURRIES SNEAKING TO THE PRIBILOF
ISLANDS. THERE IS ALSO A 979 MB LOW CENTERED 400 MI SW OF SHEMYA
MOVING EAST.

&&

.MODEL DISCUSSION...
MODELS HANDLE THE MAIN WEATHER FEATURES SATISFACTORILY THROUGH
THIS WEEKEND. THE UPPER-LOW IN THE GULF IS DEPICTED OPENING INTO
A TROUGH WITH SOME OF THE ENERGY BEGINNING TO SPLIT LATE TONIGHT.
ONE LOBE DRIFTS SE TOWARDS THE AK PANHANDLE WHILE THE OTHER PUSHES
WEST THROUGH KODIAK ISLAND AS IT REFORMS INTO AN UPPER-LOW THU
NIGHT. THIS UPPER-LOW THEN SNEAKS INTO THE EASTERN BERING FRI WITH
A POSITION SAT MORNING JUST EAST OF THE PRIBILOF ISLANDS. THE NAM
IS A BIT OF AN OUTLIER IN THAT IT IS CONSIDERABLY FURTHER NORTH
THAN THE OTHER MODELS WITH THIS DEVELOPMENT. THE UPPER-HIGH
FORMING NEAR NUNIVAK ISLAND IS SHOWN PUSHING UP THE BERING STRAIT
THROUGH FRI AND PERSISTING AS A STRONG BLOCKING FEATURE THIS
WEEKEND AS IT LURKS OVER THE NW PART OF ALASKA. MODELS MEANWHILE
STILL SHOW THE PACIFIC SYSTEM SOUTH OF UNALASKA MOVING TO AROUND
250 MILES SOUTH OF KODIAK ISLAND THU EVENING AND MAINLY CLIPPING
THE S GULF FRI BEFORE DISSIPATING NEAR THE FAR S PANHANDLE EARLY
SAT. FURTHER WEST...THE LOW NEARING THE WESTERN ALEUTIAN CHAIN
MOVES TO AROUND 200 MI SOUTH OF KISKA THU AFTERNOON BEFORE
DIPPING SE TO 350 MI SOUTH OF NIKOLSKI FRI AFTERNOON. MODELS THEN
SHOW YET ANOTHER GALE FORCE FRONT APPROACHING THE FAR WESTERN
CHAIN ON SAT.

&&

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA/GULF...
AS THE UPPER-LOW IN THE GULF SPLITS IT'S ENERGY AND MIGRATES
WESTWARD...THERE WILL BE SOME INCREASE OF CLOUDS AND SOME PASSING
SNOW SHOWERS FOR IMMEDIATE COASTAL AREAS OF THE SOUTHERN KENAI
PENINSULA THE LATTER HALF OF THU. UNLESS THIS MOISTURE WERE TO
TREND NORTH WHICH DOES NOT APPEAR LIKELY AT THIS JUNCTURE...THE
FORECAST LOOKS TO REMAIN PERSISENTLY DRY IN THE COMING DAYS ACROSS
MUCH OF THE SOUTHCENTRAL MAINLAND DUE TO THE BLOCKING HIGH TO THE
NORTHWEST. KODIAK ISLAND WILL SEE THE UPPER LOW PASS NEARLY
OVERHEAD THU NIGHT SO PRECIPITATION WILL BE A BIT STEADIER THERE.
ONSHORE FLOW WILL PERSIST IN THE LOW'S WAKE SO THIS KEEPS ELEVATED
CHANCES OF PRECIPITATION TO CLOSE OUT THE WEEK ON THE ISLAND.

SOUTHWEST ALASKA/AKPEN...
COOL AND DRY CONDITIONS TO DOMINATE MUCH OF THE SW MAINLAND AS
WELL DUE TO PROXIMITY TO THE UPPER-HIGH. THE UPPER-LOW MOVING FROM
THE GULF TO THE E BERING SEA MAY NIP PORTIONS OF BRISTOL BAY
BOROUGH WITH SOME LIGHT SNOWS ON FRI. ALONG THE AKPEN...SOME
STEADY LIGHT SNOW/RAIN WILL OVERSPREAD THE AREA WITH THE DYING
FRONT ASSOCIATED WITH THE PACIFIC LOW. THIS PRECIPITATION TRENDS
MORE SHOWERY TUE NIGHT AS THE ENERGY MOVES AWAY AND WEAKENS.

BERING SEA/ALEUTIANS...
A BRIEF REPRIEVE FROM STEADY RAIN/SNOW THIS EVENING BETWEEN THE
PACIFIC LOW PUSHING AWAY FROM THE REGION AND THE NEXT LOW
ADVANCING TOWARDS KISKA/SHEMYA. THIS NEXT SYSTEM IS CONSIDERABLY
WEAKER THAN THE AFOREMENTIONED DEPARTING PACIFIC LOW...THOUGH SOME
MIN GALE FORCE WINDS STILL POSSIBLE. THE FRONT WILL STALL AND
WEAKEN QUICKLY OVER THE CENTRAL CHAIN/BERING SEA AS IT RUNS UP
AGAINST THE STOUT UPPER-HIGH DOWNSTREAM.

&&

.LONG TERM FORECAST...
MODELS SHOW THE UPPER-HIGH OVER THE NORTHERN PART OF THE STATE
RETREATING A BIT PAST THE NORTH SLOPE EARLY TO MID NEXT WEEK. IF
IT GETS DISPLACED FAR ENOUGH TO THE NORTH...THIS WOULD ENABLE
UPPER DISTURBANCES TRAVERSING DOWN IT'S EASTERN FLANK TO PINWHEEL
UNDERNEATH IT AND WEST ACROSS THE SOUTHERN MAINLAND. RESIDUAL
ENERGY FROM THE SYSTEM CURRENTLY APPROACHING THE WESTERN CHAIN
THROUGH WILL LIKELY BE IN THE VICINITY OF 50N 150W THE LATTER
PART OF THE WEEKEND. AS THE UPPER HIGH NOSES FURTHER NORTH...THIS
TOO COULD ALLOW SOME OF THE ENERGY IN THE NE PACIFIC TO BEGIN
CREEPING BACK TOWARDS AT LEAST COASTAL AREAS OF SOUTHCENTRAL NEXT
WEEK. MODEST JET STREAM ENERGY TRAVERSING THE BERING/CHAIN WILL
KEEP THINGS SOMEWHAT ACTIVE OVER THE WESTERN AOR IN TERMS OF
PERIODS OF PRECIPITATION AND STRONG WINDS.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY FOR BLOWING SNOW...131
MARINE...GALE...130 131 138 172 179 411 412 413 414
HEAVY FREEZING SPRAY...126 127 140 160 180 185 412 414
FIRE WEATHER...NONE.

&&

JAM