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000
FXAK68 PAFC 182055
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
1255 PM AKDT FRI APR 18 2014

.ANALYSIS AND UPPER LEVELS...WATER VAPOR IMAGERY SHOWS AN INTENSE
LOW OVER THE NORTHEAST PACIFIC ABOUT TO OCCLUDE. IT HAS JUST BEGUN
A STRONG TURN TOWARD THE NORTH-NORTHEAST AS RIDGE BUILDS OUT AHEAD
OF IT. THIS SYSTEM WILL BE THE FOCUS OF WEATHER OVER THE GULF THIS
WEEKEND. MEANWHILE THE LARGE CLOSED LOW WHICH HAS BEEN SITTING
OVER THE BERING AND ALEUTIANS HAS SHIFTED EASTWARD AND IS NOW
CENTERED OVER THE SOUTHERN ALASKA PENINSULA. COLDER AIR MOVING IN
BEHIND THE LOW HAS CHANGED PRECIPITATION TO SNOW FROM THE
PRIBILOFS TO THE EASTERN ALEUTIANS...BUT SURFACE TEMPERATURES ARE
AT OR ABOVE FREEZING SO DON`T EXPECT ANY SNOW ACCUMULATION.
MULTIPLE WEAK WAVES EMBEDDED WITHIN THE FLOW AROUND THIS LOW ARE
AFFECTING MOST OF THE ALASKA REGION. THE MOST NOTEWORTHY SHORT-
WAVE EXTENDS FROM BRISTOL BAY TO THE NORTH GULF COAST AND IS
MOVING NORTHWARD. THE AIR MASS AHEAD OF THIS TROUGH IS UNSTABLE AS
INDICATED BY 850-500 LAPSE RATES OF 7.4 TO 8.2 C/KM IN 12Z
SOUNDINGS ACROSS THE SOUTHERN MAINLAND. THIS INSTABILITY IS
EVIDENT IN THE SHOWERY CHARACTERISTIC OF RADAR RETURNS THIS
MORNING. EVEN WITH INSTABILITY THE BULK OF PRECIP IS FALLING ALONG
THE COAST. A DOWNSLOPE HOLE IS NOTED OVER SOUTHCENTRAL IN THE LEE
OF THE COASTAL RANGE...HELPING KEEP LOW LEVELS PRETTY DRY INLAND.

&&

.MODEL DISCUSSION...ALL MODELS ARE PRETTY CLOSE WITH POSITION AND
STRENGTH OF INTENSE LOW OVER THE NORTHEAST PACIFIC. HOWEVER...THE
ECMWF SEEMS TO BE VERIFYING CLOSEST TO REALITY (BASED ON SATELLITE
IMAGERY). MOST NOTEWORTHY...IT IS QUICKER TO OCCLUDE THE LOW THIS
MORNING AND HAS GENERALLY SHOWN THE BEST RUN-TO-RUN CONTINUITY
WITH THIS SYSTEM THE PAST FEW DAYS. THE ONE EVIDENT TREND IN THE
LATEST RUN OF THE ECMWF RUN IS TO SLOW DOWN THE WESTWARD
PROGRESSION OF THE TRIPLE POINT LOW WHICH FORMS TONIGHT. SLOWER
MOTION MAKES SENSE WITH THE FIRST LOW ABOUT TO OCCLUDE AND BECOME
WRAPPED UP...HELPING SLOW DOWN THE FORWARD MOTION OF THE ENTIRE
SYSTEM.

THERE ARE SOME MINOR DIFFERENCES IN TRACK OF LOW WHICH DEVELOPS
OVER THE NORTHWEST PACIFIC AND MOVES TOWARD THE ALEUTIANS...BUT
NOTHING WHICH FUNDAMENTALLY AFFECTS THE FORECAST.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...SHOWERS WILL QUICKLY COME TO AN END ACROSS
SOUTHCENTRAL TONIGHT AS THE SHORT-WAVE EXIST TO THE NORTH AND
MUCH STABLER AIR MOVES IN BEHIND IT. A BUILDING RIDGE ALONG THE
NORTH GULF COAST WILL PRODUCE GUSTY GAP WINDS THIS AFTERNOON AND
EVENING...BUT THE RIDGE WILL BE QUICKLY SHUNTED NORTHWARD BY THE
APPROACHING NORTHEAST PACIFIC STORM SYSTEM AND LOW LEVEL FLOW WILL
BECOME NORTHERLY. THIS WILL AID IN DRYING THINGS OUT (AND CLEARING
OUT ANY REMAINING LOW LEVEL CLOUDS). AS HAS BEEN ADVERTISED THE
INITIAL IMPACTS OF THE PACIFIC SYSTEM WILL BE CONFINED TO KODIAK
ISLAND AND THE GULF WATERS ON SATURDAY WHILE SOUTHCENTRAL WILL
SEE SUNNY SKIES UNDERNEATH A STRENGTHENING RIDGE. THERE HAS BEEN
MORE UNCERTAINTY IN THE FORECAST FOR SOUTHCENTRAL ON SUNDAY AS THE
TRIPLE POINT LOW BECOMES DOMINANT AND CURVES WESTWARD ACROSS THE
GULF. A MAJORITY OF MODELS SHOW THE ASSOCIATED TROUGH SWINGING FAR
ENOUGH NORTH TO BRING CLOUDS AND A CHANCE OF RAIN TO THE NORTH
GULF COAST. INLAND AREAS WILL SEE SOME RESIDUAL MID TO HIGH
CLOUDS...BUT IT LOOKS LIKE CONDITIONS WILL REMAIN DRY. THE UPPER
RIDGE WILL SET UP SHOP OVER THE INTERIOR MONDAY WITH THE RIDGE
AXIS EXTENDING SOUTHWARD OVER SOUTHCENTRAL. MODELS INDICATE
POTENTIAL FOR SOME SHOWERS WITH VERY WEAK WAVES EMBEDDED IN THE
UPPER FLOW...BUT WITH A STABLE AIR MASS IN PLACE THINK THE ONLY
CHANCE OF SHOWERS WILL BE ON THE MOUNTAINS.

SOUTHWEST ALASKA...MOSTLY CLOUDY AND SHOWERY CONDITIONS WILL
PERSIST ACROSS COASTAL SOUTHWEST THROUGH TONIGHT DUE TO PROXIMITY
TO THE LOW OVER THE SOUTHERN ALASKA PENINSULA. MODELS ARE MORE
AGGRESSIVE IN ADVECTING MOISTURE FROM NORTHEAST PACIFIC LOW
WESTWARD ACROSS THE ALASKA PENINSULA INTO BRISTOL BAY ON SATURDAY.
THUS...LOOK FRO CONTINUED CLOUDINESS WITH AREAS OF
RAIN...ESPECIALLY ALONG THE ALASKA PENINSULA. THE REST OF
SOUTHWEST ALASKA WILL DRY OUT UNDER THE INFLUENCE OF THE RIDGE
BUILDING OVER THE MAINLAND. EVEN BRISTOL BAY SHOULD DRY OUT SUNDAY
AS THE RIDGE BUILDS OVER ALL OF SOUTHWEST ALASKA. MONDAY IS MORE
UNCERTAIN AS A WEAK TROUGH LIFTS NORTHWARD UP THE WEST SIDE OF THE
RIDGE. RIGHT NOW IT DOESN`T LOOK STRONG TO PRODUCE MORE THAN A FEW
CLOUDS AND PERHAPS SOME MOUNTAIN SHOWERS.

BERING SEA/ALEUTIANS...A BRIEF BREAK WILL ENSUE SATURDAY AS THE
UPPER LOW OVER THE SOUTHERN ALASKA PENINSULA IS SHEARED APART AND
RIDGE BUILDS IN AHEAD OF A DEVELOPING NORTHWEST PACIFIC LOW. THIS
STORM SYSTEM WILL BE THE FOCUS FOR SUNDAY AND MONDAY AS IT MAKES
ITS WAY INTO THE BERING.

&&

.LONG TERM FORECAST...GENERAL OUTLOOK FOR THE DAY 4 THROUGH 7
PERIOD REMAINS CONSISTENT...WITH A LOW IN THE BERING/ALEUTIANS AND
A HIGH LATITUDE BLOCK PROVIDING DRIER AND WARMER WEATHER FOR MUCH
OF MAINLAND ALASKA. ONE CHANGE FROM YESTERDAY`S MODEL RUNS IS THAT
THE BERING LOW LOOKS LIKE IT WILL IMPACT THE SOUTHWEST COAST
TUESDAY INTO WEDNESDAY. FORECAST CONFIDENCE IS INITIALLY ABOVE
AVERAGE...BUT FALLS BY THE END OF NEXT WEEK WITH UNCERTAINTY IN
WHETHER THE THE BERING LOW WILL AFFECT SOUTHCENTRAL AS IT EXITS TO
THE NORTHEAST PACIFIC OR WHETHER THE UPPER RIDGE WILL DOMINATE AND
KEEP OUT CLOUDS AND PRECIP.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 131 132 138 150 155.
FIRE WEATHER...NONE.

&&

$$

SEB APR 14





000
FXAK68 PAFC 181327
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
527 AM AKDT FRI APR 18 2014

.ANALYSIS AND UPPER LEVELS...
A BROAD LONGWAVE TROUGH ENCOMPASSES ALASKA AND ITS SURROUNDING
WATERS. WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS A CLOSED LOW
CENTER SPINNING ALONG THE WESTERN ALASKA PENINSULA. MULTIPLE
SHORTWAVES ARE EMBEDDED THROUGH THE FLOW AROUND THE LOW CENTER. A
WEAK SHORTWAVE IS MOVING INTO THE NORTHERN GULF OF ALASKA THIS
MORNING...BUT LACKS ANY DISTINCT SURFACE FEATURE. RAIN SHOWERS ARE
DEVELOPING ALONG THE WAVE IN THE NORTHERN GULF WITH A FEW SHOWERS
MAKING IT INLAND. TO THE WEST...PATCHY FOG WITH SCATTERED RAIN AND
SNOW SHOWERS SPAN ACROSS THE BERING. THE NEXT SYSTEM THAT WILL
MOVE INTO THE SOUTHERN GULF LATER TONIGHT IS A STACKED LOW PRESSURE
SYSTEM SOUTH OF 50N AND ALONG 150W.

&&

.MODEL DISCUSSION...
MODELS CONTINUE IN GOOD AGREEMENT WITH THE OVERALL SYNOPTIC
PATTERN THROUGH SUNDAY NIGHT. RAIN AND SNOW ACTIVITY ASSOCIATED
WITH THE SHORTWAVE IN THE NORTHERN GULF WILL SPREAD INLAND TODAY
AND THEN DIMINISH AS THE WAVE MOVES NORTH. LOW PRESSURE IN THE EASTERN
BERING WILL BECOME STATIONARY AS IT IS SQUEEZED BETWEEN HIGH
PRESSURE BUILDING INTO EASTERN ALASKA AND THE WESTERN BERING. THE
RIDGE BUILDING INTO THE MAINLAND WILL ALSO SHUNT THE NORTHWARD
PROGRESSION OF THE NORTH PACIFIC LOW THAT IS CURRENTLY MOVING
TOWARD THE GULF. THE ECMWF AND GFS WERE THE FAVORED MODELS FOR
UPDATES TO THE FORECAST PACKAGE AS THEY HAD THE BEST MODEL RUN
CONSISTENCY.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
RAIN AND SNOW ALONG THE NORTHERN GULF WILL SPREAD INLAND TODAY AS
THE SHORTWAVE MOVES NORTH. THE GULF WILL SEE PERIODS OF RAIN
THROUGH THE WEEKEND AS LOW PRESSURE FROM THE NORTH PACIFIC
MEANDERS ACROSS THE SOUTHERN GULF. THIS LOW WILL BRING AN OCCLUDED
FRONT INTO THE SOUTHERN GULF TONIGHT. RAIN DEVELOPING ALONG THE
FRONT WILL BRING MODERATE TO HEAVY RAIN AT TIMES FOR KODIAK ISLAND
THROUGH SATURDAY WITH SNOW ALONG THE HIGHER ELEVATIONS INLAND.
SCATTERED SHOWERS WILL SPREAD NORTH FROM THE LOW CENTER MAKING IT
TO COASTAL LOCATIONS AND THEN DIMINISH WITH THE PREVAILING HIGH
OVER THE MAINLAND.

SOUTHWEST ALASKA...
THE UPPER LEVEL TROUGH WILL STALL OUT OVER THE EASTERN BERING SEA
THIS EVENING BEFORE DISSIPATING EARLY SATURDAY MORNING. THIS WILL
KEEP SKIES CLOUDY WITH PERIODS OF RAIN FOR BRISTOL BAY
TODAY...WITH MORE SHOWERY ACTIVITY EXPECTED FURTHER NORTH AND
WEST. ANOTHER BAND OF RAIN WILL PUSH INTO COASTAL BRISTOL BAY
EARLY SATURDAY MORNING AS A GULF LOW APPROACHES BEFORE THE ENTIRE
AREA WILL BEGIN TO CLEAR OUT LATE SATURDAY INTO SUNDAY. THE ONE
EXCEPTION TO THIS TREND WILL BE WITH A SLIGHT CHANCE OF SHOWERS
FOR THE KUSKOKWIM DELTA ON SUNDAY AS A SHARP ARCTIC TROUGH CLIPS
THE AREA.

BERING SEA/ALEUTIANS...
THE MAJORITY OF THE ACTIVE WEATHER WILL REMAIN FROM THE PRIBILOF
ISLANDS EASTWARD INTO THIS WEEKEND. SCATTERED TO NUMEROUS RAIN AND
SNOW SHOWERS WILL MIGRATE THROUGHOUT THE EASTERN BERING THROUGH
SATURDAY. FURTHER WEST...RIDGING WILL SLOWLY BEGIN TO BUILD INTO
THE WESTERN ALEUTIANS LATER TODAY...WHICH WILL BRING CLEARING
SKIES AND OTHERWISE BENIGN WEATHER THROUGH SATURDAY. MORE ACTIVE
WEATHER WILL ONCE AGAIN RETURN TO THE WESTERN ALEUTIANS SUNDAY AS
THE NEXT ALEUTIAN LOW DRAWS NEAR.

&&

.LONG TERM FORECAST...
LONG TERM FORECAST CONFIDENCE IS GAINING AS LITTLE CHANGE HAS
OCCURRED IN THE FORECAST IN THE LAST 24 HOURS. THE MODELS REMAIN
IN GOOD AGREEMENT THAT HIGH PRESSURE THAT WILL BUILD OVER MAINLAND
ALASKA EARLY NEXT WEEK WILL KEEP A MAJORITY OF THE ACTIVE WEATHER
CONFINED TO THE BERING SEA AND ALEUTIANS. THIS WILL BRING A RETURN
TO MOSTLY CLEAR SKIES AND SPRING LIKE TEMPERATURES TO MUCH THE
MAINLAND THAT WILL CONTINUE INTO THE MIDDLE OF NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 131 132 138 351 352.
FIRE WEATHER...NONE.

&&

$$

KH/DEK APR 14





000
FXAK68 PAFC 172054
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
1254 PM AKDT THU APR 17 2014

.ANALYSIS AND UPPER LEVELS...A LONG-WAVE TROUGH ENCOMPASSES ALL OF
ALASKA AND THE NORTH PACIFIC WITH A NEAR ZONAL SUBTROPICAL JET
CENTERED ALONG 40N. THERE IS ONE NOTABLE SHORTWAVE AND BUCKLE IN
THE JET BETWEEN 160W AND 170W WITH A DEEPENING SURFACE LOW. THIS
SYSTEM WILL BE THE PRIMARY FOCUS THIS WEEKEND OVER THE GULF.
MEANWHILE EMBEDDED WITHIN THE LONG-WAVE TROUGH IS A LARGE CLOSED
LOW CENTERED OVER THE SOUTHERN BERING/EASTERN ALEUTIANS. NUMEROUS
SHORT-WAVES CONTINUE TO ROTATE AROUND THIS LOW PRODUCING MAINLY
SHOWERS ACROSS THE REGION. ON THE DOWNSTREAM SIDE OF THE UPPER
TROUGH A COUPLE OF SHORT-WAVES/SURFACE LOWS OVER THE GULF ARE
LIFTING NORTHWARD. SUNNY SKIES DOMINATE MUCH OF THE SOUTHERN
MAINLAND THIS MORNING...ESPECIALLY INLAND AREAS. THAT WILL
CHANGE TONIGHT AS THE GULF SYSTEMS PROGRESS INLAND.

&&

.MODEL DISCUSSION...MODELS ALL INITIALIZED REASONABLY WELL WITH
MAJOR FEATURES AND SOLUTIONS GENERALLY SHOW THE SAME IDEA WITH
HANDLING OF INTENSIFYING SYSTEM OVER THE NORTH CENTRAL PACIFIC
AND DEVELOPMENT OF ANOTHER DEEP LOW OVER THE NORTHWEST
PACIFIC/ALEUTIANS THIS WEEKEND. AS THE NORTH PACIFIC LOW CURVES
NORTHEASTWARD TOWARD THE GULF EXPECT TRIPLE POINT DEVELOPMENT
CLOSER TO THE SUBTROPICAL JET. ALL OF THE GLOBAL MODELS SHOW THIS
ALTHOUGH THEY DIFFER ON EXACT POSITION OF THE TWO LOWS. SOLUTIONS
BEGIN TO DIVERGE FURTHER AS THESE LOWS CONSOLIDATE BACK INTO A
SINGLE LOW. THESE DIFFERENCES WILL MAINLY AFFECT KODIAK ISLAND
AND THE GULF MARINE AREAS. FOR NOW PREFER THE VERY CONSISTENT
ECMWF.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...A SERIES OF WEAK UPPER LEVEL WAVES WILL
LIFT NORTHWARD ACROSS SOUTHCENTRAL ALASKA TONIGHT THROUGH FRIDAY.
AS HAS BEEN THE CASE IN RECENT DAYS THE BULK OF PRECIP WILL FALL
ALONG THE COAST...HOWEVER DO EXPECT MOST AREAS TO SEE A SHOWER OR
TWO AS THESE WAVES PASS OVERHEAD. AS THESE WAVES EXIT TO THE NORTH
AND THE PACIFIC LOW APPROACHES THE GULF A SURFACE RIDGE WILL
BRIEFLY BUILD ALONG THE NORTH GULF COAST AND KICK UP WINDS ALONG
TURNAGAIN ARM (INTO PORTIONS OF ANCHORAGE) AND THE KNIK RIVER
VALLEY (INTO PALMER). THIS RIDGE WILL BE SHUNTED QUICKLY NORTHWARD
FRIDAY NIGHT AS THE LOW CONTINUES NORTHWARD. FLOW WILL SHIFT TO
OFFSHORE AHEAD OF THE LOW WHILE A SHORT-WAVE RIDGE BUILDS OVER
SOUTHCENTRAL. THIS WILL PRODUCE A CRYSTAL CLEAR DAY FOR MOST OF
SOUTHCENTRAL ON SATURDAY. CLOUDS WILL LIKELY BE ON THE INCREASE
SUNDAY WITH A CHANCE OF RAIN ALONG THE COAST AS WAVES ROTATING
AROUND THE LOW APPROACH SOUTHCENTRAL.

SOUTHWEST ALASKA...A SERIES OF SHORT-WAVES ROTATING AROUND THE
BERING/ALEUTIAN LOW WILL ROTATE THROUGH SOUTHCENTRAL TONIGHT
THROUGH FRIDAY NIGHT. PRECIP WON`T BE WIDESPREAD...BUT LIKE
SOUTHCENTRAL EXPECT MOST AREAS TO SEE A LITTLE SOMETHING.
MARGINALLY COLDER AIR WILL MOVE IN FROM THE SOUTHWEST WITH THE
STRONGEST OF THE UPPER WAVES LATE TONIGHT AND FRIDAY MORNING. THIS
MAY TURN PRECIPITATION TO SNOW OR A MIX OF RAIN AND SNOW...BUT
DON`T EXPECT ANY ACCUMULATION. THE BERING SYSTEM WILL COMPLETELY
FALL APART THIS WEEKEND AS THE LOW MOVING INTO THE GULF BECOMES
DOMINANT. GENERALLY EXPECT DRY CONDITIONS...ALTHOUGH SOME CLOUDS
AND PRECIP MAY BACK THERE WAY FROM THE WESTERN GULF INTO BRISTOL
BAY.

BERING SEA/ALEUTIANS...THE BERING/ALEUTIAN LOW WILL WOBBLE ITS WAY
EASTWARD TOWARD THE SOUTHERN ALASKA PENINSULA TONIGHT AND FRIDAY
AND WILL THEN BE TORN APART AS HALF OF THE ENERGY IS PUSHED
NORTHWARD BY THE SYSTEM MOVING INTO THE GULF AND THE OTHER HALF
IS PUSHED SOUTHWARD AS A RIDGE BUILDS INTO THE WESTERN BERING
AHEAD OF A RAPIDLY INTENSIFYING LOW OVER THE NORTHWEST PACIFIC.
THIS RIDGE WILL QUICKLY SHIFT EASTWARD...PROVING BENIGN CONDITIONS
FOR THE WESTERN TO EASTERN BERING THROUGH THE WEEKEND. THE
NORTHWEST PACIFIC LOW WILL BOTTOM OUT AS IT NEARS THE
ALEUTIANS...SO EXPECT FULL IMPACT OF THIS STORM TO AFFECT THE
ALEUTIANS ON SUNDAY.

&&

.LONG TERM FORECAST...THE SYSTEM MOVING TO THE WESTERN ALEUTIANS
ON SUNDAY WILL BE THE PRIMARY FEATURE OF CONCERN IN THE DAY 4
THROUGH 7 PERIOD AS IT SLOWLY WEAKENS AND SPREADS OUT ACROSS THE
BERING SEA POSSIBLY AS FAR AS THE SOUTHWEST COAST. THE GULF LOW
WILL SINK SOUTHWARD WHILE RIDGING SETS UP OVER MUCH OF MAINLAND
ALASKA. THUS EXPECT A QUIET WEEK OVER SOUTHCENTRAL AND INTERIOR
SOUTHWEST ALASKA. LOW LEVEL THICKNESS LOOK VERY SPRING-LIKE...SO
EVEN WITH SOME SUNSHINE EXPECT HIGH TEMPERATURES TO BE NEAR NORMAL
IN THE 40S ALONG THE COAST AND 50S INLAND. WITH GOOD AGREEMENT IN
THE LARGER SCALE PATTERN AMONG THE GLOBAL MODELS...FORECAST
CONFIDENCE IS ABOVE AVERAGE.

&&

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

$$

SEB APR 14





000
FXAK68 PAFC 171342
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
542 AM AKDT THU APR 17 2014

.ANALYSIS AND UPPER LEVELS...
A BROAD AREA OF LOW PRESSURE ENCOMPASSES THE SOUTHERN MAINLAND AND
SURROUNDING WATERS. VISIBLE SATELLITE IMAGERY SHOW TWO MAIN
PRESSURE CENTERS EARLY THIS MORNING...WITH ONE SPINNING NORTH OF
DUTCH HARBOR AND THE OTHER OVER THE SOUTHEASTERN GULF. THESE LOW
PRESSURE CIRCULATIONS ARE KEEPING RAGGED LOW AND MID LEVEL CLOUDS
OVER THE SOUTHERN MAINLAND AND SURROUNDING WATERS. DISTURBANCES
IN THE FLOW ALOFT ARE BRINGING LIGHT RAIN SHOWERS ACROSS THE GULF
...SOUTHWESTERN MAINLAND AND MUCH OF THE BERING. THE NEARLY ZONAL
JET STREAM...WHICH IS SITUATED SOUTH OF THE ALEUTIANS...IS MOVING
A BETTER ORGANIZED LOW PRESSURE SYSTEM SOUTH OF ATKA.

&&

.MODEL DISCUSSION...
MODELS ARE IN RELATIVELY GOOD AGREEMENT WITH THE OVERALL SYNOPTIC
PATTERN THROUGH SATURDAY WITH ONLY MINOR DIFFERENCES IN THE WEAK
WAVES MOVING ABOUT THE UPPER LOW CENTERS. MODELS ARE STRUGGLING
WITH THE TRACK OF THE ORGANIZED SYSTEM CURRENTLY SOUTH OF THE
CENTRAL ALEUTIANS. GALE WINDS WITH THIS SYSTEM WILL EFFECT THE
GULF WATERS THIS WEEKEND AND SHOULD BE MONITORED AS THE TRACK OF
THIS SYSTEM MAY TURN FURTHER NORTH THAN EXPECTED.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
LOW PRESSURE IN THE SOUTHWESTERN GULF WILL MOVE TOWARD THE EASTERN
KENAI THIS AFTERNOON. PERIODS OF RAIN WILL EFFECT THE WESTERN GULF
THROUGH TONIGHT WITH SCATTERED RAIN SHOWERS MOVING INTO THE KENAI
EARLY AFTERNOON. WEAK DISTURBANCES WILL MOVE SCATTERED RAIN
SHOWERS ACROSS THE GULF TODAY AND TONIGHT...WITH A FEW RAIN AND
SNOW SHOWERS PUSHING INLAND. WINDS CONTINUE TO BE RELATIVELY
LIGHT OVER THE NEXT SEVERAL DAYS...WITH THE EXCEPTION OF LOCAL
GUSTY WINDS THROUGH CHANNELED TERRAIN. A WEAK FRONT WILL MOVE FROM
THE SOUTHERN GULF LATE THIS AFTERNOON TO THE NORTHERN GULF EARLY
FRIDAY MORNING BRINGING ANOTHER ROUND OF RAIN. AS THE FRONT
PUSHES INLAND...RAIN WILL BECOME LESS ORGANIZED BUT SHOULD SPREAD
RAIN THROUGH ALL OF SOUTHCENTRAL ON FRIDAY BEFORE DISSIPATING.
SATURDAY WILL BE THE DRIEST DAY IN THE THE SHORT TERM WITH THE
NEXT SYSTEM MOVING UP FROM THE NORTHEASTERN PACIFIC ON SUNDAY.

SOUTHWEST ALASKA...
AS THE WEAK SURFACE LOW OVER THE WESTERN GULF SLOWLY MIGRATES
WESTWARD THIS MORNING...RAIN AND SNOW SHOWERS WILL BEGIN TO
REDEVELOP AND BECOME MORE WIDESPREAD OVER BRISTOL BAY.
TEMPERATURES WILL REMAIN ABOVE FREEZING DURING TODAY...WHICH WILL
KEEP ANY ACCUMULATIONS LIGHT AND LIMITED TO THE MORNING HOURS.
WEAK CYCLONIC FLOW WILL THEN SPREAD THROUGHOUT THE SOUTHWEST
MAINLAND THIS EVENING AND KEEP THE AREA UNDER CLOUDY SKIES WITH
SCATTERED RAIN AND SNOW SHOWERS INTO THE WEEKEND. THE NEXT ROUND
OF WIDESPREAD RAIN WILL THEN RETURN TO SOUTHERN BRISTOL BAY ON
SATURDAY EVENING AS THE NEXT LOW APPROACHES THE SOUTHWESTERN GULF.

BERING SEA/ALEUTIANS...ANOTHER WEAK LOW WILL SLOWLY MIGRATE FROM
THE SOUTHERN BERING TO THE AKPENN TODAY...KEEPING SCATTERED TO
NUMEROUS RAIN SHOWERS IN THE FORECAST FROM DUTCH HARBOR EAST
THROUGH THE WORK WEEK. OUT WEST...THE WEATHER WILL REMAIN MOSTLY
DRY WITH LIGHT WINDS AS WEAK RIDGING MOVES INTO THE AREA. THIS
WILL CONTINUE UNTIL THE NEXT ALEUTIAN LOW APPROACHES THE WESTERN
ALEUTIANS LATE SUNDAY.SOUTHWEST ALASKA...

&&

.LONG TERM FORECAST...
THE MODELS ARE BEGINNING TO TREND SLOWER WITH THE EASTWARD
PROGRESSION OF THE ALEUTIAN LOW EARLY NEXT WEEK AS IT BEGINS TO
INTERACT WITH RIDING THAT WILL DEVELOP OVER THE MAINLAND. THERE IS
NOW GOOD AGREEMENT THAT THE GULF LOW WILL MOVE OUT OF THE REGION
ON MONDAY...WHICH WILL BRING A PERIOD OF QUIET WEATHER AND CLEAR
SKIES TO MUCH OF THE MAINLAND UNTIL MID WEEK AS THE ALEUTIAN LOW
BEGINS TO APPROACH THE SOUTHWEST COAST.


&&

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

$$

KH/DEK APR 14





000
FXAK68 PAFC 162139
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
139 PM AKDT WED APR 16 2014

.ANALYSIS AND UPPER LEVELS...

A BROAD UPPER LEVEL TROUGH EXTENDS FROM KAMCHATKA TO SOUTHEAST AK
THIS AFTERNOON. AN EMBEDDED CLOSED LOW IS OVER THE SOUTHERN
BERING AND ALEUTIANS...WITH ANOTHER SMALL LOW OVER THE SOUTHERN
GULF OF ALASKA. AT THE SURFACE...A BROAD AREA OF WEAK LOW
PRESSURE COVERS THE THE ENTIRE FORECAST AREA...WITH A COUPLE OF
LOW CENTERS OVER THE WESTERN AND EASTERN ALEUTIANS...THE WESTERN
GULF AND NEAR SOUTHEAST AK. THE MAIN JET REMAINS WELL SOUTH OF
ALASKA AND IS PRETTY MUCH DISASSOCIATED FROM THE FEATURES
AFFECTING THE FORECAST AREA. AS A RESULT VERY WEAK FLOW ALOFT IS
ALL THAT IS AVAILABLE FOR MOVING AROUND SYSTEMS. THIS MEANS
CURRENT WEATHER WILL CONSIST OF WEAK AND POORLY TIMED WAVES OF
PRECIPITATION MOVING ACROSS THE FORECAST AREA...SEPARATED BY
PERIODS OF DRY CONDITIONS WITH SIGNIFICANT BREAKS IN THE OVERCAST.

&&

.MODEL DISCUSSION...

GUIDANCE IS IN AGREEMENT OVER THE WESTERN DOMAIN FOR THE FIRST
DAY OR SO AS THE BERING AND ALEUTIAN LOWS BECOME ABSORBED INTO A
BROAD TROUGH OF LOW PRESSURE OVER THE EASTERN BERING AND ALASKA
PENINSULA. THIS AREA OF LOW PRESSURE REMAINS MORE OR LESS OVER THE
SAME AREA INTO SAT...AND THE FORECAST IS HANDLED FAIRLY WELL WITH
THE GFS. THE STORY IS DIFFERENT OVER THE EASTERN DOMAIN AS THE
TRAJECTORY OF THE INITIAL LOW NEAR SOUTHEAST AK VARIES BY MODEL.
THE EC AND NAM BRING THE LOW INTO THE HAINES SKAGWAY END OF THE
PANHANDLE ON THU...WHILE THE GFS BRINGS THE LOW TO YAKUTAT. THIS
MORE EASTERN TRAJECTORY OF THE EC-NAM MAY BE ATTRIBUTED TO A
SLIGHTLY MORE EASTWARD EXTENSION OF THE UPPER LOW DURING THAT
TIME. SINCE THIS SYSTEM MAINLY AFFECTS THE JUNEAU FORECAST AREA
WHERE THE EC AND NAM SOLUTIONS WERE PREFERRED...WE DEFERRED AND
UTILIZED THAT SOLUTION FOR THE EASTERN DOMAIN AS WELL. THIS MODEL
COMBINATION WAS ALSO APPLIED TO THE NEXT NORTH PACIFIC LOW. THIS
BEGINS TO AFFECT THE GULF WITH WIND FRI AFTERNOON AND BECOMES A
ZONALLY ORIENTED LOW ACROSS THE SOUTHERN GULF ON SAT.

&&

.SHORT TERM FORECAST...

BERING SEA/ALEUTIANS...EAST TO NORTHEAST FLOW WILL BE FOLLOWED BY
NORTH FLOW ON FRI AND NORTHWEST ON SAT. ISOLATED TO SCATTERED
RAIN AND SNOW SHOWERS CAN BE EXPECTED THROUGH SAT.

SOUTHWEST ALASKA...SCATTERED RAIN AND SNOW SHOWERS WILL PERSIST
THROUGH SAT AS CYCLONIC FLOW PERSISTS ACROSS THE REGION.

SOUTHCENTRAL ALASKA...INLAND AREAS WILL HAVE MAINLY DRY
CONDITIONS...EXCEPT FOR MOUNTAIN RAIN AND SNOW SHOWERS...UNTIL
THE SECOND LOW MOVES INLAND THU NIGHT INTO FRI. THE ASSOCIATED
TROUGH WILL SPREAD MORE WIDESPREAD PRECIPITATION INLAND INTO SAT.
HIGH PRESSURE THEN WILL BUILD OVER THE AREA WITH DRYING. COASTAL
AREAS WILL HAVE PLENTY OF SHOWER ACTIVITY UNTIL HIGH PRESSURE
BUILDS FRI INTO SAT. THE ARRIVAL OF THE SECOND LOW WILL BRING A
ROUND OF RAIN AND SMALL CRAFT TO GALE FORCE WINDS THROUGH THE
WEEKEND.

&&

.LONG TERM FORECAST...

IN THE WEST...HIGH PRESSURE WILL SPREAD DRY CONDITIONS ACROSS THE
REGION INTO SUN...BUT A NORTH PACIFIC LOW WILL THEN SPREAD WIND
AND RAIN LATER SUN THROUGH MID WEEK AS IT MOVES ALONG THE SOUTHERN
SIDE OF THE ALEUTIANS. IN THE EAST...THE LOW PRESSURE NEAR THE
GULF OF ALASKA REMAIN IN THE SAME VICINITY WITH WIND AND RAIN
MAINLY FOR COASTAL AREAS THROUGH MON. BRIEF DRYING ON TUE WILL BE
FOLLOWED BY MORE SHOWER ACTIVITY AS THE ALEUTIAN LOW ARRIVES ON
WED.


&&

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

$$

DS APR 14





000
FXAK68 PAFC 161323
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
523 AM AKDT WED APR 16 2014

.ANALYSIS AND UPPER LEVELS...
A BROAD UPPER LEVEL TROUGH IS CENTERED OVER THE SOUTHERN BERING WITH
A WEAKER LOW CIRCULATION OVER THE SOUTHERN GULF OF ALASKA. THIS
CIRCULATION IS STREAMING LOW TO MID LEVEL CLOUDS OVER THE
SOUTHERN MAINLAND AND SURROUNDING WATERS. A WEAK UPPER LEVEL
DISTURBANCE HAS INITIATED LIGHT RAIN SHOWERS ALONG THE NORTHERN
GULF...KENAI PENINSULA AND SOUTHCENTRAL EARLY THIS MORNING. A
HEAVIER BAND OF RAIN IS DEVELOPING ALONG A SURFACE LOW IN THE
SOUTHERN GULF AND SPREADING TOWARD KODIAK. ACROSS THE
SOUTHWEST...ISOLATED TO SCATTERED SHOWERS ARE SPREAD ALONG A WEAK
BOUNDARY STRETCHING FROM KING SALMON TO HOOPER BAY. THE BERING HAS
AN OCCLUDED FRONT IS BRING COLDER TEMPERATURES INTO THE WESTERN
ALEUTIANS WITH LIGHT SNOW REPORTED AT SHEMYA EARLY THIS MORNING.

&&

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN
THROUGH FRIDAY NIGHT WITH ONLY SLIGHT DIFFERENCES IN THE WEAK
UPPER LEVEL SHORT WAVES. THE CLOSED LOW IN THE BERING WILL SLOWLY
SHIFT EAST CENTERING OVER THE ALASKA PENINSULA ON FRIDAY. THIS
PATTERN WILL KEEP PRECIPITATION CHANCES IN THE FORECAST THROUGH
THE END OF THE WEEK. NORTHERLY FLOW ACROSS THE BERING WILL ALLOW A
COLDER AIR MASS TO FILTER IN BEHIND THE LOW CENTER. ONLY MINOR
CHANGES WERE MADE IN THE SHORT TERM WITH USE OF THE ECMWF USED FOR
MOST OF THE UPDATES BEYOND 30 HOURS AS IT PREDOMINANTLY HAD THE BEST
MODEL RUN CONSISTENCY.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
RAIN WILL CONTINUE TO DEVELOP ALONG THE WESTERN GULF THROUGH
THURSDAY AS LOW THE SURFACE LOW IN THE SOUTHERN GULF MOVES SLOWLY
NORTH. SCATTERED RAIN SHOWERS ASSOCIATED WITH THIS LOW WILL SPREAD
ACROSS THE KENAI PENINSULA AND COOK INLET LATER TODAY. ISOLATED TO
SCATTERED SHOWERS WILL ALSO MOVE IN FROM THE EAST...AS A WEAK
WAVE OF ENERGY MOVES FROM THE PANHANDLE THIS MORNING. HIGHER
ELEVATIONS MAY SEE SNOW WITH MAINLY LIGHT ACCUMULATIONS. SCATTERED
PRECIPITATION WILL REMAIN IN THE FORECAST THROUGH THE WEEKEND AS
LOW PRESSURE MOVES FROM THE BERING.

SOUTHWEST ALASKA...

AN OCCLUDED FRONT CURRENTLY SITUATED ACROSS THE ALASKA PENINSULA
CONTINUES TO BRING SCATTERED RAIN SHOWERS TO THE IMMEDIATE COASTAL
AREAS OF SOUTHWEST ALASKA. ALL UPPER LEVEL SUPPORT ASSOCIATED
WITH THE FRONT HAS DISSIPATED...WHICH WILL IN TURN CAUSE THE
OCCLUDED FRONT TO GRADUALLY DISSIPATE BY EARLY THIS AFTERNOON.
THROUGH THE REMAINDER OF THE WORK WEEK...A SERIES OF UPPER LEVEL
IMPULSES WILL ROTATE AROUND AREAS OF LOW PRESSURE LOCATED IN THE
GULF OF ALASKA AS WELL AS IN THE BERING SEA. AS THESE IMPULSES
INTERACT WITH MOISTURE STREAMING IN FROM THE SOUTHEAST...SCATTERED
RAIN SHOWERS WILL DEVELOP ACROSS SOUTHWEST ALASKA AND LIKELY
LINGER INTO THE WEEKEND. TEMPERATURES THROUGH THE REMAINDER OF THE
WEEK WILL REMAIN NEARLY TEN DEGREES ABOVE NORMAL.

BERING SEA/ALEUTIANS...

A LARGE MULTI CENTERED AREA OF LOW PRESSURE WILL SLOWLY MAKE PROGRESS
TO THE SOUTH AND EAST TODAY AND THURSDAY BEFORE ULTIMATELY PHASING
WITH A BROAD TROUGH OF LOW PRESSURE THAT WILL ENCOMPASS MUCH OF
THE SOUTHERN HALF OF ALASKA BY EARLY FRIDAY. NUMEROUS RAIN SHOWERS
WILL CONTINUE ALONG THE ALEUTIAN ISLANDS THROUGH THURSDAY PRIOR TO
THE LOW PHASING WITH THE BROAD AREA OF LOW PRESSURE. ONCE THE LOWS
PHASE...SCATTERED RAIN SHOWERS WILL CONTINUE TO BE SEEN AS A SERIES
OF SHORTWAVES TRAVERSE THE PERIPHERY OF THE UPPER LEVEL TROUGH.
COLDER AIR WILL BEGIN TO FILTER IN ACROSS THE WESTERN HALF OF THE
BERING SEA LATE TODAY INTO THURSDAY AS COLDER AIR IS ADVECTED
SOUTHWARD ON THE WESTERN PERIPHERY OF THE COMPLEX LOW.

&&

.LONG TERM FORECAST...
MODELS HAVE COME INTO SLIGHTLY BETTER AGREEMENT IN RESPECT TO A
LOW PUSHING INTO THE GULF OF ALASKA FROM THE NORTHERN PACIFIC
DURING THE WEEKEND. HOWEVER...MODELS STRUGGLE WITH THE DEVELOPMENT
AND ORIENTATION OF THIS LOW AS THE ECMWF WANTS TO EXTEND THE
SURFACE TROUGH TOWARD SOUTHWEST ALASKA WHILE THE GFS CONSOLIDATES
MOST OF THE ENERGY OVER THE EASTERN GULF. THE EVENTUAL POSITION
AND ORIENTATION OF THIS LOW WILL MAKE A SIGNIFICANT DIFFERENCE ON
THE PRECIPITATION PATTERN ACROSS MUCH OF SOUTHERN ALASKA AND WILL
NEED TO BE MONITORED CLOSELY. OVER THE BERING SEA...MODELS ARE IN
BETTER AGREEMENT THAN YESTERDAY WITH AN AREA OF LOW PRESSURE
SKIRTING TO THE SOUTH OF THE WESTERN AND CENTRAL ALEUTIANS SUNDAY
AND INTO THE BEGINNING OF NEXT WEEK. HOWEVER...MODEL SOLUTIONS
OVER THE GULF OF ALASKA AND BERING SEA DIVERGE SIGNIFICANTLY BY
EARLY TUESDAY WHICH LEADS TO A BELOW AVERAGE CONFIDENCE IN THE
LONG TERM FORECAST AT THIS TIME.

&&

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

$$

KH/MMC APR 14





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