Small Craft Advisory 480, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
219 PM AKDT MON JUN 16 2014

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL TROUGH EXTENDS FROM EASTERN RUSSIA TO THE ALCAN THIS
AFTERNOON WITH AN EMBEDDED CUT-OFF LOW OVER THE AKPEN AND BRISTOL
BAY...AND A SECOND CUT-OFF ANCHORED NORTH OF EXTREME EASTERN
RUSSIA. UPPER RIDGES ARE OVER KAMCHATKA AND SOUTHEAST AK AND THE
ALCAN. AT THE SURFACE...A LOW PRESSURE CENTER IS SOUTHEAST OF
KODIAK ISLAND...WITH A RIDGE ALONG THE NORTH GULF COAST. A WEATHER
FRONT IS DRAPED ACROSS THE NORTHERN GULF. HIGH PRESSURE EXTENDS
FROM THE NORTH PACIFIC ACROSS THE BERING...WITH NORTHWEST FLOW AT
THE SURFACE.

&&

.MODEL DISCUSSION...

MODELS ARE IN FAIR AGREEMENT FOR THE NEXT SEVERAL DAYS. THE LOW
SOUTHEAST OF KODIAK ISLAND WILL INTENSIFY TONIGHT BENEATH THE
LEFT EXIT REGION OF THE JET. THE LOW WILL THEN WEAKEN AS IT MOVES
TO SOUTHERN PRINCE WILLIAM SOUND NEAR MONTAGUE ISLAND BY TUE
EVENING. THE LOW WILL THEN BE ABSORBED INTO A BROAD AREA OF LOW
PRESSURE...THAT WILL INCLUDE A THERMAL TROUGH ALONG THE ALEUTIAN
AND ALASKA RANGES. THE STRONG FRONT ASSOCIATED WITH THE KODIAK
LOW WILL REACH THE NORTH GULF COAST AND PRINCE WILLIAM SOUND THIS
EVENING AND LINGER INTO TUE MORNING BEFORE DISSIPATING.

LOW PRESSURE OVER EASTERN RUSSIA WILL ENTER THE NORTHERN BERING
TUE AFTERNOON AND BE ABSORBED INTO THE AREA OF MAINLAND LOW
PRESSURE WED AFTERNOON. ON THU THIS AREA OF LOW PRESSURE MOVES
OVER THE NORTHWESTERN GULF.

THE FORECAST UTILIZES SOME NAM EARLY...AND THEN GEM AND EC
THROUGH THE REST OF THE SHORT RANGE.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...

RAIN ON WINDWARD SLOPES AND STRONG WIND THROUGH CHANNELED TERRAIN
CAN BE EXPECTED INTO TUE. A STRONG GRADIENT DOWN COOK INLET WILL
KEEP MOST WINDS AND RAIN OUT OF ANCHORAGE EXCEPT FOR A BRIEF
PERIOD THIS EVENING DURING FRONTAL PASSAGE. AS THE SURFACE LOW
MOVES CLOSER TO THE SOUND...RAIN AND SHOWERS WILL SPREAD INLAND
TUE AND WED...WITH A FEW THUNDERSTORMS POSSIBLE ALONG THE KENAI
PENINSULA TUE AFTERNOON. LATER ON WED AND INTO THU RAIN ASSOCIATED
WITH THE EASTERN RUSSIA LOW WILL ARRIVE OVER SOUTHCENTRAL.

SOUTHWEST ALASKA...

SHOWERS WILL PERSIST OVER THE REGION UNTIL A BRIEF BREAK TUE
NIGHT INTO WED. IMPULSES MOVING THROUGH THE UPPER LOW WILL BRING
AFTERNOON AND EVENING THUNDERSTORMS THIS EVENING AND TUE. RAIN
ARRIVES ALONG THE COAST WITH THE RUSSIAN LOW WED MORNING AND
REACHES THE ALASKA AND ALEUTIAN RANGES WED EVENING. DRYING BEGINS
LATER ON THU.

BERING SEA/ALEUTIANS...

RAIN SHOWERS ON NORTHWEST SURFACE FLOW WILL PERSIST INTO TUE
MORNING. ANOTHER ROUND OF PRECIPITATION BEGINS TUE NIGHT INTO WED
AS THE RUSSIAN LOW TRANSITS THE EASTERN HALF OF THE AREA. ON THU
A NORTH PACIFIC LOW ENTERS THE WESTERN ALEUTIANS WITH RAIN
DEVELOPING THROUGH THE EVENING.

&&

.LONG TERM FORECAST...

THE EXTENDED PERIOD (FRI THROUGH MON) WILL STILL BE SHAPED BY THE
REMNANTS OF THE CURRENTLY DEVELOPING SYSTEM IN THE GULF OF ALASKA.
HOWEVER ONCE THE UPPER LOW SETTLES INTO PLACE GUIDANCE DOES NOT
HAVE A GOOD HANDLE ON WHAT TO DO WITH EACH INDIVIDUAL PIECE OF
ENERGY ROTATING AROUND THE MAIN LONGWAVE. THE MAIN DIFFERENCE IS
HOW LONG RANGE MODELS HANDLE A PIECE OF ENERGY THAT MOVES UP THE
WESTERN CANADIAN COAST TOWARD THE YUKON. THAT SHORTWAVE WILL
EITHER TRACK ACROSS THE INTERIOR AS AN EASTERLY WAVE...OR CLOSE
OFF FROM THE GULF COMPLEX AND DRIFT NORTHWARD. THE FORECAST
CURRENTLY TAKES THE EASTERLY WAVE ROUTE ALBEIT NOT AS STRONG AS
THE ECMWF WOULD SUGGEST. EXPECT NEAR NORMAL TO SLIGHTLY
ABOVE NORMAL TEMPERATURES WITH A CHANCE OF SHOWERS...ESPECIALLY
ALONG THE MOUNTAINS FOR THE EXTENDED PERIOD.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 120 129 130 131 132 138 139 140
         STORMS 119 125

FIRE WEATHER...NONE.

&&

DS/ML JUN 14