Small Craft Advisory 600, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
131 PM AKDT SAT AUG 9 2014

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE NORTHWEST GULF OF ALASKA. A
FRONT ASSOCIATED WITH THIS LOW IS SITUATED ALONG THE NORTH GULF
COAST. THERE IS AN UPPER LOW OVER THE KAMCHATKA PENINSULA THAT IS
RAPIDLY MOVING EASTWARD. A WEAK RIDGE IS IN BETWEEN THESE TWO LOWS
AND ANOTHER RIDGE IS OVER NORTHERN AND CENTRAL ALASKA.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT ON THE UPPER LEVEL PATTERN
THROUGH 84 HOURS. THE NAM BEGINS TO STRUGGLE IN THE GULF AFTER 60
HOURS...AND IS NOT QUITE UP TO SPEED WITH THE OTHER MODELS FROM
THE BEGINNING ON THE KAMCHATKA LOW. THERE ARE NATURALLY SOME
DIFFERENCES ON SMALLER SCALE FEATURES AND MOISTURE...BUT NOT
ANYTHING TO BE TOO CONCERNED ABOUT. FORECAST CONFIDENCE IS NEAR TO
MAYBE SLIGHTLY ABOVE NORMAL.

&&

.SHORT TERM FORECAST...

FOR SOUTH CENTRAL ALASKA...THE NORTHWEST GULF LOW WILL SLIDE INTO
THE CENTRAL GULF BY SUNDAY AFTERNOON. MOISTURE WILL CONTINUE TO
WRAP AROUND THIS LOW INTO SOUTH CENTRAL ALASKA...WITH THE MAJORITY
OF THE PRECIPITATION ALONG THE GULF COAST. THE HEAVIEST RAIN WHICH
IS CURRENTLY OVER THE EASTERN KENAI PENINSULA WILL EASE UP TONIGHT
AS THE MAIN MOISTURE PLUME SURGES EASTWARD INTO THE PANHANDLE.
DOWN-SLOPE EFFECTS WILL WEAKEN SUNDAY NIGHT AS THE UPPER LOW
WEAKENS AND MOVES NORTH...WHICH WILL ALLOW AN INCREASE IN SHOWERS
INLAND. AS THE FORMER KAMCHATKA LOW APPROACHES FROM THE WEST (BY
MONDAY AFTERNOON OVER THE SOUTH CENTRAL BERING SEA) THE GULF LOW
WILL BECOME AN OPEN WAVE AND BE PUSHED INLAND BY THE BERING LOW
FOR CONTINUED SHOWERS OVER THE AREA INTO MONDAY NIGHT. ON TUESDAY
SOUTHERLY WINDS ALOFT WILL DEVELOP AS THE BERING LOW MOVES CLOSER
AND CONTINUES TO INCREASE IN SIZE.

FOR SOUTHWEST ALASKA...SHOWERS WILL CONTINUE TO DIMINISH THROUGH
SUNDAY AS THE GULF LOW SLIDES EAST. ON SUNDAY NIGHT SHOWERS WILL
BE LIMITED MAINLY TO THE AREAS NEAR THE ALASKA/ALEUTIAN RANGES AS
MOISTURE FROM THE GULF LOW STRUGGLES TO GET TOO FAR WEST AND WEAK
RIDGING FORMS AHEAD OF THE KAMCHATKA/BERING SEA LOW. BY LATE
MONDAY THE LEADING FRONT FROM THE BERING SYSTEM WILL REACH THE
SOUTHWEST COAST...PUSHING RAPIDLY INLAND MONDAY NIGHT. SHOWERY
WEATHER WILL CONTINUE ON TUESDAY WITH CYCLONIC FLOW ALOFT. THIS
WILL BE TEMPERED A LITTLE BY THE UPPER LEVEL FLOW BEING FROM THE
SOUTH RATHER THAN THE SOUTHWEST.

FOR THE BERING SEA/ALEUTIANS...THE LEADING FRONT FROM THE
KAMCHATKA LOW WILL PUSH INTO THE CENTRAL ALEUTIANS TONIGHT AND
ACROSS THE EASTERN ALEUTIANS SUNDAY NIGHT. THE UPPER LOW ITSELF
WILL BE CENTERED OVER ATTU ISLAND SUNDAY EVENING...MOVING EAST
THROUGH TUESDAY AND CENTERED BETWEEN DUTCH HARBOR AND THE
PRIBILOFS BY TUESDAY AFTERNOON.

&&

.LONG TERM FORECAST...
THE SPIRIT OF THE MODELS ARE SIMILAR WITH REGARDS TO THE UPPER-LVL
PATTERN MID TO LATE NEXT WEEK. THE BERING/ALEUTIAN SYSTEM WILL BE
FILLING BUT BROAD ENOUGH TO EXERT INFLUENCE TO THE SENSIBLE
WEATHER ACROSS THE AOR. THIS PARENT UPPER-LOW CENTERED NEAR
UNALASKA NEXT WED NIGHT WILL TRACK TOWARDS THE BRISTOL BAY
WESTERN CAPES NEXT FRI. THIS PATTERN WILL CONTINUE TO SUPPORT A
GENERAL SOUTH TO SOUTHEAST ONSHORE FLOW INTO SOUTHCENTRAL/SOUTHWEST
AK AND YIELD MOSTLY CLOUDY CONDITIONS AND CHANCES FOR RAIN. AS THE
LOW WILL BE WEAKENING...THE SHOWERS ON IT'S BACK SIDE ACROSS THE
ALEUTIAN CHAIN AND BERING SEA WILL BECOME FEWER AND FAR BETWEEN.

REMNANT ENERGY FROM TYPHOON GENEVIEVE PASSING WEST OF MIDWAY
ISLAND IN THE CENTRAL PACIFIC THIS WEEKEND WILL BE DRIFTING
NORTHWARD TOWARDS 35 TO 40N LATITUDE MID NEXT WEEK. IT REMAINS
PLAUSIBLE THAT WHAT IS LEFT OF IT'S ENERGY AND MOISTURE WILL BE
SWOOPED UP INTO THE JET STREAM. THE CORE OF THIS UPPER JET
CENTERED AROUND 45N LATITUDE LOOKS TO BEGIN POKING A BIT FURTHER
NORTHWARD AS THE BERING/ALEUTIAN SYSTEM FILLS AND FLATTENS OUT.
REGARDLESS OF ANY TROPICAL ENERGY INTERACTING WITH IT...THE
THREAT OF STRONGER STORM SYSTEMS INCREASES FOR THE GULF OF AK
TOWARDS NEXT WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 119 177 178.
FIRE WEATHER...NONE.

&&

LUDWIG/JAM AUG 14