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000
FXAK68 PAFC 222143
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
143 PM AKDT TUE JUL 22 2014

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW CENTERED OVER BRISTOL BAY...AND AN
UPPER LEVEL TROUGH THAT EXTENDS NORTH/NORTHEAST FROM THE LOW WITH
ITS AXIS RUNNING THROUGH BETHEL TO NEAR BARROW. THERE IS A LARGE
AND STRONG RIDGE CENTERED OVER THE SOUTHWEST BERING SEA THAT IS
NUDGING INTO THE CENTRAL BERING. THERE IS A RIDGE OVER SOUTHEAST
ALASKA THAT IS BEING ERODED BY THE WESTERN ALASKA LOW/TROUGH.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT 60
HOURS. FROM 60 TO 84 HOURS THE MODELS BEGIN TO DISAGREE SOMEWHAT
ON THE STRENGTH/SPEED/ORIENTATION OF SHORT-WAVES SWINGING SOUTH ON
THE BACKSIDE OF THE TROUGH/LOW WHICH BY THIS TIME WILL BE OVER
CENTRAL ALASKA/NORTHERN GULF. THE MODELS DO CONTINUE TO AGREE WELL
ON THE RIDGE OVER THE BERING SEA. FORECAST CONFIDENCE FOR THE
AFTERNOON PACKAGE IS NEAR TO ABOVE NORMAL.

&&

.SHORT TERM FORECAST...

FOR SOUTH CENTRAL ALASKA...THE RIDGE THAT HAS BEEN OVER THE AREA
WILL SLIDE OFF TO THE EAST TONIGHT AS THE BRISTOL BAY LOW PUSHES
ACROSS KODIAK ISLAND...THEN INTO THE NORTHERN GULF OF ALASKA ON
WEDNESDAY. THE LOW WILL THEN STALL OVER THE NORTHEAST GULF ON
THURSDAY AND REMAIN THERE THROUGH FRIDAY. ON WEDNESDAY NIGHT AND
THURSDAY A SYSTEM PUSHING OUT OF NORTHEAST RUSSIA WILL RE-ENFORCE
THE TROUGH OVER WESTERN/CENTRAL ALASKA. THIS SYSTEM WILL PUSH INTO
SOUTH CENTRAL THURSDAY NIGHT...THEN IT WILL SPLIT APART TO THE
NORTH AND SOUTH OF THE GULF LOW ON FRIDAY. THE TROUGH (BY THIS
TIME SITUATED NORTH/SOUTH OVER THE CENTER OF THE STATE) WILL
"SHARPEN UP" ON THURSDAY AND FRIDAY AS THE SOUTHWEST BERING SEA
RIDGE MOVES INTO THE CENTRAL BERING SEA.

FOR SOUTHWEST ALASKA...THE TROUGH/LOW WILL PUSH THROUGH TONIGHT
BRINGING RAIN/SHOWERS TO MOST OF THE AREA. THE "RE-ENFORCING"
SYSTEM WILL PUSH INTO SOUTHWEST ALASKA FROM THE NORTHWEST LATE
WEDNESDAY INTO THURSDAY. ON THURSDAY NIGHT AND FRIDAY THE FLOW
ALOFT WILL BE FAIRLY STRONG FROM THE NORTH-NORTHWEST AS THE RIDGE
BUILDS INTO THE CENTRAL BERING SEA. THURSDAY NIGHT AND FRIDAY LOOK
FAIRLY DRY AS THE BERING RIDGE WILL NUDGE MOST OF THE MOISTURE TO
THE EAST.

FOR THE BERING SEA/ALEUTIANS...THE MAIN STORY WILL BE THE RIDGE
OVER THE SOUTHWEST BERING SEA BUILDING EASTWARD. LIGHT AND SHOWERY
PRECIPITATION WILL BE NUDGED EASTWARD AHEAD OF THE RIDGE. THE
STRONG STABILITY ASSOCIATED WITH THE RIDGE WILL CAP THE MARINE
LAYER AND KEEP PLENTY OF LOW CLOUDS AND FOG ACROSS THE
AREA...WHICH OF COURSE IS THE TYPE OF WEATHER THAT IS EXPECTED
THIS TIME OF YEAR.


&&

.LONG TERM FORECAST...
THE LONG RANGE PATTERN (FRIDAY NIGHT THROUGH TUESDAY) WILL
GENERALLY CONSIST OF A STRONG BLOCKING RIDGE OVER THE CENTRAL
BERING SEA/ALEUTIANS AND A TROUGH OVER THE GULF OF ALASKA AND OVER
NORTHERN ALASKA. THIS WILL RESULT IN NORTHWESTERLY FLOW ALOFT FOR
THE MAINLAND. A FEW SYSTEMS WILL PUSH THROUGH SOUTHERN
ALASKA...BRINGING CONSIDERABLE CLOUDS AND SOME PRECIPITATION. DUE
TO THE DIRECTION OF THE UPPER FLOW AND THE FACT THAT THESE SYSTEMS WILL
BE TRANSIENT...PRECIPITATION WILL GENERALLY BE SHOWERY AND
ACCUMULATIONS ARE NOT EXPECTED TO BE VERY HIGH.

THE WPC (WEATHER PREDICTION CENTER) FORECAST GENERALLY LEANS
TOWARD THE 00Z ECMWF ENSEMBLE MEAN...BUT EVEN THE OPERATIONAL
ECMWF AND GFS AS WELL AS THE GFS ENSEMBLE MEAN ARE NOT ALL THAT
DIFFERENT.

&&

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

$$

LUDWIG/CASSELL JUL 14





000
FXAK68 PAFC 222143
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
143 PM AKDT TUE JUL 22 2014

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW CENTERED OVER BRISTOL BAY...AND AN
UPPER LEVEL TROUGH THAT EXTENDS NORTH/NORTHEAST FROM THE LOW WITH
ITS AXIS RUNNING THROUGH BETHEL TO NEAR BARROW. THERE IS A LARGE
AND STRONG RIDGE CENTERED OVER THE SOUTHWEST BERING SEA THAT IS
NUDGING INTO THE CENTRAL BERING. THERE IS A RIDGE OVER SOUTHEAST
ALASKA THAT IS BEING ERODED BY THE WESTERN ALASKA LOW/TROUGH.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT 60
HOURS. FROM 60 TO 84 HOURS THE MODELS BEGIN TO DISAGREE SOMEWHAT
ON THE STRENGTH/SPEED/ORIENTATION OF SHORT-WAVES SWINGING SOUTH ON
THE BACKSIDE OF THE TROUGH/LOW WHICH BY THIS TIME WILL BE OVER
CENTRAL ALASKA/NORTHERN GULF. THE MODELS DO CONTINUE TO AGREE WELL
ON THE RIDGE OVER THE BERING SEA. FORECAST CONFIDENCE FOR THE
AFTERNOON PACKAGE IS NEAR TO ABOVE NORMAL.

&&

.SHORT TERM FORECAST...

FOR SOUTH CENTRAL ALASKA...THE RIDGE THAT HAS BEEN OVER THE AREA
WILL SLIDE OFF TO THE EAST TONIGHT AS THE BRISTOL BAY LOW PUSHES
ACROSS KODIAK ISLAND...THEN INTO THE NORTHERN GULF OF ALASKA ON
WEDNESDAY. THE LOW WILL THEN STALL OVER THE NORTHEAST GULF ON
THURSDAY AND REMAIN THERE THROUGH FRIDAY. ON WEDNESDAY NIGHT AND
THURSDAY A SYSTEM PUSHING OUT OF NORTHEAST RUSSIA WILL RE-ENFORCE
THE TROUGH OVER WESTERN/CENTRAL ALASKA. THIS SYSTEM WILL PUSH INTO
SOUTH CENTRAL THURSDAY NIGHT...THEN IT WILL SPLIT APART TO THE
NORTH AND SOUTH OF THE GULF LOW ON FRIDAY. THE TROUGH (BY THIS
TIME SITUATED NORTH/SOUTH OVER THE CENTER OF THE STATE) WILL
"SHARPEN UP" ON THURSDAY AND FRIDAY AS THE SOUTHWEST BERING SEA
RIDGE MOVES INTO THE CENTRAL BERING SEA.

FOR SOUTHWEST ALASKA...THE TROUGH/LOW WILL PUSH THROUGH TONIGHT
BRINGING RAIN/SHOWERS TO MOST OF THE AREA. THE "RE-ENFORCING"
SYSTEM WILL PUSH INTO SOUTHWEST ALASKA FROM THE NORTHWEST LATE
WEDNESDAY INTO THURSDAY. ON THURSDAY NIGHT AND FRIDAY THE FLOW
ALOFT WILL BE FAIRLY STRONG FROM THE NORTH-NORTHWEST AS THE RIDGE
BUILDS INTO THE CENTRAL BERING SEA. THURSDAY NIGHT AND FRIDAY LOOK
FAIRLY DRY AS THE BERING RIDGE WILL NUDGE MOST OF THE MOISTURE TO
THE EAST.

FOR THE BERING SEA/ALEUTIANS...THE MAIN STORY WILL BE THE RIDGE
OVER THE SOUTHWEST BERING SEA BUILDING EASTWARD. LIGHT AND SHOWERY
PRECIPITATION WILL BE NUDGED EASTWARD AHEAD OF THE RIDGE. THE
STRONG STABILITY ASSOCIATED WITH THE RIDGE WILL CAP THE MARINE
LAYER AND KEEP PLENTY OF LOW CLOUDS AND FOG ACROSS THE
AREA...WHICH OF COURSE IS THE TYPE OF WEATHER THAT IS EXPECTED
THIS TIME OF YEAR.


&&

.LONG TERM FORECAST...
THE LONG RANGE PATTERN (FRIDAY NIGHT THROUGH TUESDAY) WILL
GENERALLY CONSIST OF A STRONG BLOCKING RIDGE OVER THE CENTRAL
BERING SEA/ALEUTIANS AND A TROUGH OVER THE GULF OF ALASKA AND OVER
NORTHERN ALASKA. THIS WILL RESULT IN NORTHWESTERLY FLOW ALOFT FOR
THE MAINLAND. A FEW SYSTEMS WILL PUSH THROUGH SOUTHERN
ALASKA...BRINGING CONSIDERABLE CLOUDS AND SOME PRECIPITATION. DUE
TO THE DIRECTION OF THE UPPER FLOW AND THE FACT THAT THESE SYSTEMS WILL
BE TRANSIENT...PRECIPITATION WILL GENERALLY BE SHOWERY AND
ACCUMULATIONS ARE NOT EXPECTED TO BE VERY HIGH.

THE WPC (WEATHER PREDICTION CENTER) FORECAST GENERALLY LEANS
TOWARD THE 00Z ECMWF ENSEMBLE MEAN...BUT EVEN THE OPERATIONAL
ECMWF AND GFS AS WELL AS THE GFS ENSEMBLE MEAN ARE NOT ALL THAT
DIFFERENT.

&&

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

$$

LUDWIG/CASSELL JUL 14




000
FXAK68 PAFC 221332
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
532 AM AKDT TUE JUL 22 2014

.ANALYSIS AND UPPER LEVELS...
A PROGRESSIVE SPLIT-STREAM PATTERN REMAINS IN PLACE ACROSS THE
ALASKAN DOMAIN THIS MORNING. THIS PATTERN HAS BEEN GENERALLY IN
PLACE FOR ALMOST 2 WEEKS...AND FEATURES A PROGRESSION OF UPPER
LOWS/TROUGHS MOVING THROUGH INTERIOR ALASKA AND ANOTHER SEPARATE
PROGRESSION OF DISTURBANCES ACROSS THE ALEUTIANS AND INTO THE
SOUTHERN GULF. CURRENTLY...A DISTURBANCE IS MOVING ONSHORE OVER
NORTHWEST ALASKA...WITH A SOUTHERN STREAM UPPER LOW NEAR DUTCH
HARBOR. THE AXIS OF THE RIDGE THAT MADE FOR SUCH A NICE DAY
ACROSS SOUTHCENTRAL YESTERDAY HAS SLID EASTWARD...WITH DEEP-LAYER
(BUT WEAK) SOUTHWEST FLOW SPREADING INTO ALL OF SOUTHERN ALASKA.
A MUCH LARGER RIDGE IS BEGINNING TO TAKE SHAPE OVER THE WESTERN
BERING...WHERE MARINE FOG/STRATUS REMAIN WIDESPREAD. A FEW SHOWERS
HAVE MOVED ONSHORE OVER SOUTHWEST ALASKA AS BOTH THE NORTHERN AND
SOUTHERN STREAM DISTURBANCES SLOWLY APPROACH THE COAST...THOUGH
NONE ARE LOOKING PARTICULARLY IMPRESSIVE AT THIS TIME.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN EXCELLENT OVERALL AGREEMENT IN THE MOVEMENT OF
THE MAIN WEATHER FEATURES OVER THE NEXT SEVERAL DAYS. THE RIDGE IN
THE BERING SEA WILL CONTINUE TO STRENGTHEN AND WILL BECOME THE
DOMINANT WEATHER-MAKER ACROSS THE AREA. IN THE LAST 24 HOURS THE
MODELS HAVE STRUGGLED A BIT WITH WEATHER THE RIDGE AXIS WILL BE
OVER THE NORTHWEST BERING OR THE NORTHEAST BERING. THIS WILL HAVE
MOST SIGNIFICANT IMPACTS DOWNSTREAM ACROSS MAINLAND ALASKA
CONCERNING AMPLIFICATION OF SHORTWAVES DROPPING DOWN THE FRONT OF
THIS RIDGE. WITH THE MODELS TRENDING A BIT FURTHER WESTWARD WITH
THE RIDGE AXIS IN THE LAST 24 HOURS...NOT SURPRISINGLY A NORTHERN
STREAM TROUGH COMING OVER THE RIDGE NOW LOOKS AS IF IT WILL
AMPLIFY AND BRING A ROUND OF STEADY RAIN TO MUCH OF SOUTH CENTRAL
ALASKA SOMETIME IN THE THURSDAY NIGHT OR FRIDAY TIMEFRAME. THUS
WILL TREND THE FORECAST THIS DIRECTION. OTHERWISE...WITH GOOD
OVERALL AGREEMENT...THE HIGH RESOLUTION MODELS WERE LEANED ON FOR
SMALL-SCALE DETAILS.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
MIDLEVEL CLOUDS WILL BE ON THE INCREASE TODAY...BUT WILL NOT
BE A MAJOR DETRIMENT TO ANOTHER NICE DAY OVERALL. INCREASING
SOUTHERLY FLOW BEHIND THE DEPARTING RIDGE WILL PROVIDE AN
ADDITIONAL KICK TO TYPICAL DIURNAL SEA BREEZES AROUND THE REGION
TODAY...THOUGH NOT EXTREME BY ANY MEANS. ANOTHER IMPACT OF THIS
BROAD SOUTHERLY FLOW WILL BE THE POSSIBLE MOVEMENT OF SOME LOW
CLOUDINESS FROM NEAR KODIAK ISLAND TOWARD THE NORTH GULF COAST
LATER TODAY. MEANWHILE...WITH THIS HIGH PRESSURE/RIDGING NOSING
INTO THE NORTHERN GULF THERE IS A CHANCE SOUTHERLY WINDS ALONG
THE COPPER RIVER MAY JOIN WITH A SURGING THERMAL TROUGH AND LOW RH
VALUES...BUT WITH GENERALLY WEAK AND SLOW-MOVING SURFACE FEATURES
IT IS MOST LIKELY THAT BOTH FIRE WEATHER CRITERIA (WIND AND RH)
WILL NOT QUITE REACH SIGNIFICANT LEVELS. BY THIS EVENING CLOUD-
COVER WILL INCREASE FOR MOST AREAS...WITH THE PRESENCE OF THE
UPPER LOW NEAR KODIAK ISLAND LIKELY KEEPING SOME SCATTERED SHOWER
ACTIVITY ALONG THE COASTLINES AND MOUNTAIN RANGES THROUGH THE
OVERNIGHT HOURS AND CONTINUING INTO WEDNESDAY.

SOUTHWEST ALASKA...
MOIST ONSHORE FLOW WILL INTENSIFY TODAY AS SHOWERS/RAIN BECOME
INCREASINGLY WIDESPREAD. MARINE FOG/STRATUS IS ALSO LIKELY TO
SURGE ONTO THE COASTLINES WITH LIMITED SPREAD INLAND AS WELL. AS
THE UPPER LOW CURRENTLY NEAR DUTCH HARBOR MOVES TOWARD KODIAK THIS
AFTERNOON THERE WILL LIKELY BE AN INCREASINGLY CONVECTIVE LOOK AND
FEEL TO SOME OF THE SHOWERS ALONG AND WEST OF THE ALEUTIAN
RANGE...LEADING TO LOCALLY HEAVIER DOWNPOURS. THE MAIN TROUGH
CLEARS TO THE EAST BY MIDDAY WEDNESDAY...BUT MODELS NOW INDICATE
AN ADDITIONAL SHORTWAVE DROPPING DOWN THE FRONT OF THE RIDGE WILL
BRING ANOTHER QUICK SHOT OF RAIN THROUGH THE AREA WEDNESDAY NIGHT
BEFORE THE BERING RIDGE DRIES OUT THE ATMOSPHERE MORE
SUBSTANTIALLY FOR THE END OF THE WEEK.

BERING SEA/ALEUTIANS...
HIGH PRESSURE IN THE REGION WILL ONLY GET STRONGER THROUGH THE END
OF THE WEEK. THIS MEANS LESS AND LESS SHOWER ACTIVITY AND MORE
AND MORE FOG/STRATUS PROBLEMS AS WE HEAD INTO THE WEEKEND.
WINDS ACROSS MUCH OF THE BERING WILL KEEP A NORTHERLY COMPONENT
OVER THE COMING DAYS...WHICH WILL ALLOW THE PACIFIC SIDE OF THE
ALEUTIAN CHAIN TO SEE BETTER CONDITIONS OVERALL THAN THE BERING
SIDE. THIS PATTERN LOOKS TO BE LOCKED IN FOR THE BETTER PART OF
THE NEXT WEEK.

&&

.LONG TERM FORECAST FROM PREVIOUS DISCUSSION...
THE LONG RANGE PATTERN (THURSDAY NIGHT THROUGH MONDAY) WILL
GENERALLY CONSIST OF A RIDGE OVER THE CENTRAL BERING SEA/ALEUTIANS
AND A TROUGH OVER THE GULF OF ALASKA AND OVER NORTHERN ALASKA.
THIS WILL RESULT IN NORTHWESTERLY FLOW ALOFT FOR THE MAINLAND. A
FEW SYSTEMS WILL PUSH THROUGH SOUTHERN ALASKA...BRINGING
CONSIDERABLE CLOUDS AND SOME PRECIPITATION. DUE TO THE DIRECTION
OF THE UPPER FLOW AND THE FACT THAT THE MAIN LOWS WILL BE TO OUR
WEST AND SOUTH...PRECIPITATION WILL GENERALLY BE SHOWERY AND
ACCUMULATIONS ARE NOT EXPECTED TO BE VERY HIGH.

THE WPC (WEATHER PREDICTION CENTER) FORECASTS ARE GENERALLY A
BLEND OF THE 00Z GFS ENSEMBLE MEAN...THE 12Z GFS DETERMINISTIC
MODEL (LESS INFLUENCE AS TIME INCREASES UNTIL BY DAY 8 IT IS NOT
USED AT ALL)...AND THE 00Z ECMWF ENSEMBLE MEAN. THE GFS IS
WEIGHTED SLIGHTLY HIGHER THAN THE ECMWF. THE AFTERNOON FORECAST
STRONGLY LEANS TOWARD THE WPC GUIDANCE.

&&

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

$$

AMD JUL 14




000
FXAK68 PAFC 212146
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
146 PM AKDT MON JUL 21 2014

.ANALYSIS AND UPPER LEVELS...
A VERY PROMINENT RIDGE IS THE BIGGEST FEATURE THAT IS NOTED ON
SATELLITE IMAGERY TODAY. THE RIDGE AXIS IS LINED UP WITH THE
ALEUTIAN RANGE THIS AFTERNOON...AND WILL SLOWLY BE SLIDING EAST.
LOW LEVEL FOG AND STRATUS IS MOVING WITH THE RIDGE AT THE
SURFACE ACROSS BRISTOL BAY. IN THE UPPER LEVELS IS A
THIN...BUT WIDESPREAD AREA OF CIRRUS THAT COVERS A LARGE PORTION
OF THE STATE...FROM THE TALKEETNA MOUNTAINS AND WEST. A FAIRLY
WOUND UP AND STACKED LOW IS MOVING SOUTHEAST ALONG THE PANHANDLE
TODAY...AND IS THE REMNANTS OF THE SYSTEM THAT MOVED THROUGH
YESTERDAY...BRINGING RAIN SHOWERS TO THE ANCHORAGE AREA. SOUTH OF
ADAK IS THE NEXT WEATHER MAKER FOR OUR AREA. THIS LOW IS BRINGING
RAIN AND CLOUDS TO MUCH OF THE ALEUTIAN CHAIN AS WELL AS THE
PRIBILOF ISLANDS.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT TODAY WITH THE EVOLUTION OF THE
RIDGE MOVING EAST AND THE INTERACTION OF THE ALEUTIAN LOW AND A
NORTHERN STREAM SHORTWAVE TROUGH THAT IS SLIDING ACROSS THE BERING
STRAIGHT THIS AFTERNOON. THE BIGGEST DIFFERENCES ARE IN LOCATION
OF THE UPPER LEVEL LOW BY THE WEDNESDAY TIMEFRAME. IT IS AROUND
THAT TIME THAT THE NAM/GFS/GEM KEEP THE UPPER LOW ABOUT 200 NM
SOUTH OF SEWARD...WHILE THE EURO PULLS IT FARTHER NORTH AND INTO
COPPER RIVER DELTA (THE PREVIOUS RUN OF THE EURO WAS CLOSE TO THE
NAM/GFS)...OUTSIDE OF THAT MINOR DIFFERENCE...TIMING OF THE
FEATURES STILL SEEMS CONSISTENT. OVERALL THE GEM AND GFS WERE
FAVORED FOR THE FORECAST PACKAGE TODAY.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
EXTENSIVE THIN CIRRUS  CLOUDS COVER THE AREA TODAY...BEST DENOTED
BY THE MILKY WHITE COLOR IN THE SKY. GIVEN THE RIGHT ANGLE...YOU
COULD ALMOST SEE A SLIGHT REDDISH HUE THAT MEANS THAT THERE IS
SMOKE PARTICULATE THAT IS COMBINED IN THE ATMOSPHERE.
REGARDLESS...PLEASANT SUMMER WEATHER WILL CONTINUE FOR SOUTH
CENTRAL THROUGH LATE TOMORROW AS THE RIDGE SLOWLY PASSES THROUGH.
BY THAT TIME THE ALEUTIAN LOW WILL BE CROSSING KODIAK AND HEADING
FOR SOUTHERN PWS. ALONG WITH THIS LOW WILL BE THE INCREASE TO MID
AND HIGH LEVEL CLOUDS AHEAD OF IT...AND STRATUS MOVING IN ALONG
THE COAST. GIVEN THE LACK OF A SIGNIFICANT SURFACE
REFLECTION...AND RELATIVELY LIGHT LOWER LEVEL FLOW...EXPECT TO SEE
SPRINKLES AND EVENTUALLY WEAK SHOWER ACTIVITY TO IMPACT THE
ANCHORAGE AREA LATE TOMORROW NIGHT AND INTO WEDNESDAY MORNING WITH
NO SIGNIFICANT DOWNSLOPE HOLE EXPECTED. AS THE LOW SLIDES SOUTH
OF PWS...RAIN ALONG THE TYPICAL UPSLOPE AREAS OF THE COAST WILL BE
EXPECTED.

SOUTHWEST ALASKA...
A DOUBLE WHAMMY WILL BE IMPACTING SOUTHWEST THROUGH TOMORROW. THE
FIRST IS FROM THE ALEUTIAN LOW MOVING TO THE EAST AND NORTHEAST.
THIS WILL BRING IN CLOUDS AND ASSOCIATED RAINS. AREAS TO THE
WEST...SUCH AS BETHEL...WILL ALSO BE SEEING RAIN AND CLOUDS BUT
THIS WILL BE DUE TO A NORTHERN STREAM WAVE AND FRONT THAT IS
DROPPING OUT OF THE ARCTIC. INSTABILITY LOOKS TO BE INCREASING
ACROSS THE LOWER Y-K DELTA LATE INTO THE AFTERNOON TOMORROW...AND
FORECAST SOUNDINGS SHOW A SLIGHTLY UNSTABLE PROFILE. NOT EXPECTING
ANY WIDESPREAD TS ACTIVITY...BUT PERHAPS A FEW STRIKES HERE OR
THERE. THE NORTHERN STREAM WAVE AND ALEUTIAN LOW WILL JOIN AND
EVOLVE TOGETHER AS THEY CROSS THE ALEUTIAN MOUNTAINS AND IMPACT
AREAS TO THE EAST.

BERING SEA/ALEUTIANS...
THE ALEUTIAN LOW WILL DOMINATE THE WEATHER PATTERN THROUGH
TOMORROW KEEPING RAIN AND LOW CLOUDS IN THE AREA. AS THE ALEUTIAN
LOW MOVES OUT OF THE BERING...ANOTHER RIDGE WILL BUILD AND TAKE
OVER THE BERING WEATHER PATTERN AGAIN. GUIDANCE IS HINTING AT SOME
BREAKS IN THE CLOUDINESS COME MID WEEK AS THE RIDGE BUILDS
IN...WITH COOLER AND DRIER AIR AHEAD OF IT. EXPECT THAT TO BE
SHORT LIVED AS THE USUAL RIDGE STRATUS DECK WILL MOVE BACK IN.

&&

.LONG TERM FORECAST...

THE LONG RANGE PATTERN (THURSDAY NIGHT THROUGH MONDAY) WILL
GENERALLY CONSIST OF A RIDGE OVER THE CENTRAL BERING SEA/ALEUTIANS
AND A TROUGH OVER THE GULF OF ALASKA AND OVER NORTHERN ALASKA.
THIS WILL RESULT IN NORTHWESTERLY FLOW ALOFT FOR THE MAINLAND. A
FEW SYSTEMS WILL PUSH THROUGH SOUTHERN ALASKA...BRINGING
CONSIDERABLE CLOUDS AND SOME PRECIPITATION. DUE TO THE DIRECTION
OF THE UPPER FLOW AND THE FACT THAT THE MAIN LOWS WILL BE TO OUR
WEST AND SOUTH...PRECIPITATION WILL GENERALLY BE SHOWERY AND
ACCUMULATIONS ARE NOT EXPECTED TO BE VERY HIGH.

THE WPC (WEATHER PREDICTION CENTER) FORECASTS ARE GENERALLY A
BLEND OF THE 00Z GFS ENSEMBLE MEAN...THE 12Z GFS DETERMINISTIC
MODEL (LESS INFLUENCE AS TIME INCREASES UNTIL BY DAY 8 IT IS NOT
USED AT ALL)...AND THE 00Z ECMWF ENSEMBLE MEAN. THE GFS IS
WEIGHTED SLIGHTLY HIGHER THAN THE ECMWF. THE AFTERNOON FORECAST
STRONGLY LEANS TOWARD THE WPC GUIDANCE.

&&

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

$$

SHEA / LUDWIG JUL 14




000
FXAK68 PAFC 212146
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
146 PM AKDT MON JUL 21 2014

.ANALYSIS AND UPPER LEVELS...
A VERY PROMINENT RIDGE IS THE BIGGEST FEATURE THAT IS NOTED ON
SATELLITE IMAGERY TODAY. THE RIDGE AXIS IS LINED UP WITH THE
ALEUTIAN RANGE THIS AFTERNOON...AND WILL SLOWLY BE SLIDING EAST.
LOW LEVEL FOG AND STRATUS IS MOVING WITH THE RIDGE AT THE
SURFACE ACROSS BRISTOL BAY. IN THE UPPER LEVELS IS A
THIN...BUT WIDESPREAD AREA OF CIRRUS THAT COVERS A LARGE PORTION
OF THE STATE...FROM THE TALKEETNA MOUNTAINS AND WEST. A FAIRLY
WOUND UP AND STACKED LOW IS MOVING SOUTHEAST ALONG THE PANHANDLE
TODAY...AND IS THE REMNANTS OF THE SYSTEM THAT MOVED THROUGH
YESTERDAY...BRINGING RAIN SHOWERS TO THE ANCHORAGE AREA. SOUTH OF
ADAK IS THE NEXT WEATHER MAKER FOR OUR AREA. THIS LOW IS BRINGING
RAIN AND CLOUDS TO MUCH OF THE ALEUTIAN CHAIN AS WELL AS THE
PRIBILOF ISLANDS.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT TODAY WITH THE EVOLUTION OF THE
RIDGE MOVING EAST AND THE INTERACTION OF THE ALEUTIAN LOW AND A
NORTHERN STREAM SHORTWAVE TROUGH THAT IS SLIDING ACROSS THE BERING
STRAIGHT THIS AFTERNOON. THE BIGGEST DIFFERENCES ARE IN LOCATION
OF THE UPPER LEVEL LOW BY THE WEDNESDAY TIMEFRAME. IT IS AROUND
THAT TIME THAT THE NAM/GFS/GEM KEEP THE UPPER LOW ABOUT 200 NM
SOUTH OF SEWARD...WHILE THE EURO PULLS IT FARTHER NORTH AND INTO
COPPER RIVER DELTA (THE PREVIOUS RUN OF THE EURO WAS CLOSE TO THE
NAM/GFS)...OUTSIDE OF THAT MINOR DIFFERENCE...TIMING OF THE
FEATURES STILL SEEMS CONSISTENT. OVERALL THE GEM AND GFS WERE
FAVORED FOR THE FORECAST PACKAGE TODAY.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
EXTENSIVE THIN CIRRUS  CLOUDS COVER THE AREA TODAY...BEST DENOTED
BY THE MILKY WHITE COLOR IN THE SKY. GIVEN THE RIGHT ANGLE...YOU
COULD ALMOST SEE A SLIGHT REDDISH HUE THAT MEANS THAT THERE IS
SMOKE PARTICULATE THAT IS COMBINED IN THE ATMOSPHERE.
REGARDLESS...PLEASANT SUMMER WEATHER WILL CONTINUE FOR SOUTH
CENTRAL THROUGH LATE TOMORROW AS THE RIDGE SLOWLY PASSES THROUGH.
BY THAT TIME THE ALEUTIAN LOW WILL BE CROSSING KODIAK AND HEADING
FOR SOUTHERN PWS. ALONG WITH THIS LOW WILL BE THE INCREASE TO MID
AND HIGH LEVEL CLOUDS AHEAD OF IT...AND STRATUS MOVING IN ALONG
THE COAST. GIVEN THE LACK OF A SIGNIFICANT SURFACE
REFLECTION...AND RELATIVELY LIGHT LOWER LEVEL FLOW...EXPECT TO SEE
SPRINKLES AND EVENTUALLY WEAK SHOWER ACTIVITY TO IMPACT THE
ANCHORAGE AREA LATE TOMORROW NIGHT AND INTO WEDNESDAY MORNING WITH
NO SIGNIFICANT DOWNSLOPE HOLE EXPECTED. AS THE LOW SLIDES SOUTH
OF PWS...RAIN ALONG THE TYPICAL UPSLOPE AREAS OF THE COAST WILL BE
EXPECTED.

SOUTHWEST ALASKA...
A DOUBLE WHAMMY WILL BE IMPACTING SOUTHWEST THROUGH TOMORROW. THE
FIRST IS FROM THE ALEUTIAN LOW MOVING TO THE EAST AND NORTHEAST.
THIS WILL BRING IN CLOUDS AND ASSOCIATED RAINS. AREAS TO THE
WEST...SUCH AS BETHEL...WILL ALSO BE SEEING RAIN AND CLOUDS BUT
THIS WILL BE DUE TO A NORTHERN STREAM WAVE AND FRONT THAT IS
DROPPING OUT OF THE ARCTIC. INSTABILITY LOOKS TO BE INCREASING
ACROSS THE LOWER Y-K DELTA LATE INTO THE AFTERNOON TOMORROW...AND
FORECAST SOUNDINGS SHOW A SLIGHTLY UNSTABLE PROFILE. NOT EXPECTING
ANY WIDESPREAD TS ACTIVITY...BUT PERHAPS A FEW STRIKES HERE OR
THERE. THE NORTHERN STREAM WAVE AND ALEUTIAN LOW WILL JOIN AND
EVOLVE TOGETHER AS THEY CROSS THE ALEUTIAN MOUNTAINS AND IMPACT
AREAS TO THE EAST.

BERING SEA/ALEUTIANS...
THE ALEUTIAN LOW WILL DOMINATE THE WEATHER PATTERN THROUGH
TOMORROW KEEPING RAIN AND LOW CLOUDS IN THE AREA. AS THE ALEUTIAN
LOW MOVES OUT OF THE BERING...ANOTHER RIDGE WILL BUILD AND TAKE
OVER THE BERING WEATHER PATTERN AGAIN. GUIDANCE IS HINTING AT SOME
BREAKS IN THE CLOUDINESS COME MID WEEK AS THE RIDGE BUILDS
IN...WITH COOLER AND DRIER AIR AHEAD OF IT. EXPECT THAT TO BE
SHORT LIVED AS THE USUAL RIDGE STRATUS DECK WILL MOVE BACK IN.

&&

.LONG TERM FORECAST...

THE LONG RANGE PATTERN (THURSDAY NIGHT THROUGH MONDAY) WILL
GENERALLY CONSIST OF A RIDGE OVER THE CENTRAL BERING SEA/ALEUTIANS
AND A TROUGH OVER THE GULF OF ALASKA AND OVER NORTHERN ALASKA.
THIS WILL RESULT IN NORTHWESTERLY FLOW ALOFT FOR THE MAINLAND. A
FEW SYSTEMS WILL PUSH THROUGH SOUTHERN ALASKA...BRINGING
CONSIDERABLE CLOUDS AND SOME PRECIPITATION. DUE TO THE DIRECTION
OF THE UPPER FLOW AND THE FACT THAT THE MAIN LOWS WILL BE TO OUR
WEST AND SOUTH...PRECIPITATION WILL GENERALLY BE SHOWERY AND
ACCUMULATIONS ARE NOT EXPECTED TO BE VERY HIGH.

THE WPC (WEATHER PREDICTION CENTER) FORECASTS ARE GENERALLY A
BLEND OF THE 00Z GFS ENSEMBLE MEAN...THE 12Z GFS DETERMINISTIC
MODEL (LESS INFLUENCE AS TIME INCREASES UNTIL BY DAY 8 IT IS NOT
USED AT ALL)...AND THE 00Z ECMWF ENSEMBLE MEAN. THE GFS IS
WEIGHTED SLIGHTLY HIGHER THAN THE ECMWF. THE AFTERNOON FORECAST
STRONGLY LEANS TOWARD THE WPC GUIDANCE.

&&

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

$$

SHEA / LUDWIG JUL 14





000
FXAK68 PAFC 202152
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
152 PM AKDT SUN JUL 20 2014

.ANALYSIS AND UPPER LEVELS...
THE MOST PROMINENT FEATURE TO ANALYZE THIS AFTERNOON IS A LARGE
TROUGH THAT HAS BEEN CARVING ITS WAY ACROSS ALASKA THESE PAST FEW
DAYS. AN UPPER LEVEL LOW HAS BEEN FORMING AT THE BASE OF THIS
TROUGH AND CAN BE SEEN QUITE WELL ON AFTERNOON WATER VAPOR
IMAGERY. AT THE SURFACE...A WEAK LOW FORMED ACROSS PRINCE WILLIAM
SOUND AND APPEARS TO BE SLOWLY RETROGRADING TO THE WEST. THIS IS
MOST APPARENT ON PAIH 0.5 DEGREE VOLUME SCAN. ACROSS BRISTOL BAY
AND THE EASTERN ALEUTIANS IS A TRANSIENT RIDGE. SOUTHWEST OF THE
THE ALEUTIANS IS AN UPPER LEVEL LOW THAT IS SLOWLY MOVING TO THE
EAST. ALONG THE WESTERN SIDE OF THE BERING SEA RIDGE IS A WEAK
SHORTWAVE THAT IS CLIMBING UP THE WESTERN EXTENT OF
RIDGE...CROSSING THE WESTERN CHAIN THIS AFTERNOON.

&&

.MODEL DISCUSSION...
ALL IN ALL...THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM.
THERE ARE ONLY MINOR DIFFERENCES IN THE UPPER LEVELS WITH THE LOW
DIVING SOUTHEAST FROM PWS. ALL GUIDANCE IS IN GOOD AGREEMENT WITH
THE STRENGTH OF THE RIDGE MOVING ACROSS THE CHAIN AND AKPEN TODAY.
DIFFERENCES BEGIN TO SHOW IN THE OVERNIGHT PERIOD OF TUESDAY WITH
THE ALEUTIAN LOW AND HOW IT WILL EVOLVE AS IT MOVES CLOSER TO THE
MAINLAND. THE LATEST GEM-REG / ECMWF AND GFS SEEM TO BE CONSISTENT
WITH TIMING OF THIS FEATURE. THE PAST FEW RUNS OF THE NAM HAVE
BEEN STRUGGLING TO SHOW ANY CONSISTENCY AND THAT WAS LARGELY
TOSSED FOR THIS FORECAST PACKAGE. SHORT TERM FORECASTS WERE TIED
CLOSER TO THE GEM FOR BOTH DOMAINS AND MID RANGE WAS A MIX OF THE
GFS AND ECMWF.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
THE MAJORITY OF THE SHOWER ACTIVITY HAS WAINED FOR THE EASTERN
HALF OF THE REGION. CLOUD TOP TEMPERATURES CONTINUE TO WARM AND
SHOWER ACTIVITY ACROSS PWS AS WELL AS THE COPPER RIVER BASIN IS
COMING TO A CLOSE THIS EVENING. THE SURFACE LOW THAT DEVELOPED IN
WESTERN PWS LOOKS LIKE IT IS MOVING A BIT SLOWER THAN
EXPECTED...AND MAY BE RETROGRADING SLIGHTLY TO THE WEST...AND WILL
KEEP A BIT MORE CLOUD COVER ACROSS THE ANCHORAGE AREA THIS
EVENING. AS THE LOW PULLS OUT OF PWS...CLOUDS WILL DO THE SAME AND
WE SHOULD SEE GRADUAL CLEARING OVERNIGHT. RIDGING WILL BEGIN TO
SETTLE IN FROM THE WEST AND A PLEASANT START TO THE WORK WEEK WILL
TAKE PLACE. H85 TEMPERATURES WILL JUMP FROM ABOUT 1.5 DEG C TO
7-8 ACROSS THE ANCHORAGE AREA. ASSUMING MOST OF THAT WARMTH IS
REALIZED TOMORROW...WE CAN VERY EASILY SEE TEMPERATURES JUMP INTO
MID 70S BY THE AFTERNOON HOURS. THE NEXT FRONT WILL THEN SWEEP
ACROSS THE STATE STARTING LATE TOMORROW...AND INTERACT WITH A LOW
THAT IS MOVING ACROSS THE ALEUTIAN CHAINS TODAY...BRINGING THE
NEXT CHANCE FOR POPS TO SOUTH CENTRAL INTO THE TUESDAY
EVENING/WEDNESDAY TIME FRAME.


SOUTHWEST ALASKA...
RAIN AND CLOUDS HAVE DIMINISHED AND CONDITIONS ACROSS THE AREA ARE
PROGGED TO BE DRY THROUGH TOMORROW AND EARLY INTO TUESDAY. WITH
FAIRLY ABUNDANT MOISTURE AND A RIDGE BUILDING OVERHEAD...FOG WILL
SPILL OVER FROM THE SEA AND ALSO DEVELOP ALONG SOME INLAND AREAS
TONIGHT. THE ALEUTIAN LOW THAT IS SOUTH OF SHEMYA WILL WORK
EAST/NORTHEAST AND WILL EVENTUALLY BRING SHOWERS SPREADING FROM
WEST TO EAST TO THE AREA.

BERING SEA/ALEUTIANS...
THE SUMMERTIME RIDGE WITH THE TYPICAL FOG AND STRATUS WILL
CONTINUE. A SHORTWAVE RIDGE AND THE ABUNDANT MOISTURE PLUME TO THE
SOUTH ARE HELPING TO PUSH AND ENHANCEMENT NOTED IN SATELLITE
IMAGERY NORTH BETWEEN ATKA AND DUTCH. GIVEN THE LACK OF
OBSERVATIONS/GROUND TRUTH...IT IS ASSUMED THAT THERE IS SOME RAIN
COMING OUT OF THIS FEATURE. ALL GUIDANCE TAKES THIS WAVE AND
WEAKENS IT AS IT WORKS NORTH THROUGH THE PRIBS...BRINGING THE NEXT
CHANCE OF RAIN INTO THE EVENING HOURS...WHICH IS JUST A LITTLE MORE
THAN THE -DZ THAT AS BEEN EVER PRESENT. THE LOW SOUTH OF SHEMYA
WILL THEN SLOWLY WORK EAST THROUGH THE BEGINNING OF THE
WEEK...BRINGING RAIN/CLOUD CHANCES EAST AND TOWARDS THE AKPEN BY
MIDWEEK.

&&

.LONG TERM FORECAST...
THE SECOND HALF OF THE WEEK WILL SEE A PERSISTENT UPPER LEVEL LOW
OVER THE GULF OF ALASKA WITH A TROUGH EXTENDING OVER SOUTH CENTRAL
THROUGH THE INTERIOR. THIS TROUGH AND LOW WILL SLOWLY MOVE
EASTWARD AS A LARGE UPPER LEVEL HIGH IN THE WESTERN BERING SEA
WEDNESDAY MOVES EASTWARD THROUGH THE REST OF THE WEEK. THERE WAS A
LITTLE BIT OF UNCERTAINTY YESTERDAY HOW STRONG THIS RIDGE WILL BE
AND HOW FAR EAST IT WILL MOVE BY NEXT WEEKEND. CONFIDENCE IS NOW
INCREASING THAT THIS RIDGE WILL BE SUFFICIENTLY STRONG TO DISLODGE
THE PERSISTENT LOW IN THE GULF AND BECOME THE MAIN WEATHER FEATURE
NEXT WEEKEND THROUGH EARLY NEXT WEEK. IN SOUTHCENTRAL THIS PATTERN
SHOULD TRANSLATE TO AFTERNOON AND EVENING SHOWERS...ESPECIALLY
OVER ELEVATED TERRAIN...IN THE MIDDLE OF THE WEEK WITH LESS SEEN
EACH DAY UNTIL THERE ARE NOT TOO MANY AROUND BY SATURDAY. THE ONE
SIGNIFICANT CONCERN TO WATCH TOWARD NEXT WEEKEND CONCERNING THIS
RIDGE IS THAT THERE IS STILL SOME COLD UPPER LEVEL LOWS LURKING
AROUND IN THE ARCTIC OCEAN. SHOULD ONE OR MORE OF THESE COLD LOWS
RIDE DOWN THE EASTERN SIDE OF THE RIDGE THEY COULD BRING A PERIOD
OF RAINFALL...AND THEN RAPIDLY CLEAR OUT AGAIN. IN SOUTHWEST
ALASKA THE SHOWERS OVER ELEVATED TERRAIN SHOULD BE MOSTLY OVER
AFTER THURSDAY. HOWEVER THE COASTAL AREAS WILL BE AT RISK FOR LOW
CLOUDS AND FOG AS THERE WILL LIKELY BE WIDESPREAD STRATUS OVER THE
BERING SEA UNDER THIS RIDGE.

&&

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

$$

SHEA/EZ JUL 14




000
FXAK68 PAFC 202152
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
152 PM AKDT SUN JUL 20 2014

.ANALYSIS AND UPPER LEVELS...
THE MOST PROMINENT FEATURE TO ANALYZE THIS AFTERNOON IS A LARGE
TROUGH THAT HAS BEEN CARVING ITS WAY ACROSS ALASKA THESE PAST FEW
DAYS. AN UPPER LEVEL LOW HAS BEEN FORMING AT THE BASE OF THIS
TROUGH AND CAN BE SEEN QUITE WELL ON AFTERNOON WATER VAPOR
IMAGERY. AT THE SURFACE...A WEAK LOW FORMED ACROSS PRINCE WILLIAM
SOUND AND APPEARS TO BE SLOWLY RETROGRADING TO THE WEST. THIS IS
MOST APPARENT ON PAIH 0.5 DEGREE VOLUME SCAN. ACROSS BRISTOL BAY
AND THE EASTERN ALEUTIANS IS A TRANSIENT RIDGE. SOUTHWEST OF THE
THE ALEUTIANS IS AN UPPER LEVEL LOW THAT IS SLOWLY MOVING TO THE
EAST. ALONG THE WESTERN SIDE OF THE BERING SEA RIDGE IS A WEAK
SHORTWAVE THAT IS CLIMBING UP THE WESTERN EXTENT OF
RIDGE...CROSSING THE WESTERN CHAIN THIS AFTERNOON.

&&

.MODEL DISCUSSION...
ALL IN ALL...THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM.
THERE ARE ONLY MINOR DIFFERENCES IN THE UPPER LEVELS WITH THE LOW
DIVING SOUTHEAST FROM PWS. ALL GUIDANCE IS IN GOOD AGREEMENT WITH
THE STRENGTH OF THE RIDGE MOVING ACROSS THE CHAIN AND AKPEN TODAY.
DIFFERENCES BEGIN TO SHOW IN THE OVERNIGHT PERIOD OF TUESDAY WITH
THE ALEUTIAN LOW AND HOW IT WILL EVOLVE AS IT MOVES CLOSER TO THE
MAINLAND. THE LATEST GEM-REG / ECMWF AND GFS SEEM TO BE CONSISTENT
WITH TIMING OF THIS FEATURE. THE PAST FEW RUNS OF THE NAM HAVE
BEEN STRUGGLING TO SHOW ANY CONSISTENCY AND THAT WAS LARGELY
TOSSED FOR THIS FORECAST PACKAGE. SHORT TERM FORECASTS WERE TIED
CLOSER TO THE GEM FOR BOTH DOMAINS AND MID RANGE WAS A MIX OF THE
GFS AND ECMWF.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
THE MAJORITY OF THE SHOWER ACTIVITY HAS WAINED FOR THE EASTERN
HALF OF THE REGION. CLOUD TOP TEMPERATURES CONTINUE TO WARM AND
SHOWER ACTIVITY ACROSS PWS AS WELL AS THE COPPER RIVER BASIN IS
COMING TO A CLOSE THIS EVENING. THE SURFACE LOW THAT DEVELOPED IN
WESTERN PWS LOOKS LIKE IT IS MOVING A BIT SLOWER THAN
EXPECTED...AND MAY BE RETROGRADING SLIGHTLY TO THE WEST...AND WILL
KEEP A BIT MORE CLOUD COVER ACROSS THE ANCHORAGE AREA THIS
EVENING. AS THE LOW PULLS OUT OF PWS...CLOUDS WILL DO THE SAME AND
WE SHOULD SEE GRADUAL CLEARING OVERNIGHT. RIDGING WILL BEGIN TO
SETTLE IN FROM THE WEST AND A PLEASANT START TO THE WORK WEEK WILL
TAKE PLACE. H85 TEMPERATURES WILL JUMP FROM ABOUT 1.5 DEG C TO
7-8 ACROSS THE ANCHORAGE AREA. ASSUMING MOST OF THAT WARMTH IS
REALIZED TOMORROW...WE CAN VERY EASILY SEE TEMPERATURES JUMP INTO
MID 70S BY THE AFTERNOON HOURS. THE NEXT FRONT WILL THEN SWEEP
ACROSS THE STATE STARTING LATE TOMORROW...AND INTERACT WITH A LOW
THAT IS MOVING ACROSS THE ALEUTIAN CHAINS TODAY...BRINGING THE
NEXT CHANCE FOR POPS TO SOUTH CENTRAL INTO THE TUESDAY
EVENING/WEDNESDAY TIME FRAME.


SOUTHWEST ALASKA...
RAIN AND CLOUDS HAVE DIMINISHED AND CONDITIONS ACROSS THE AREA ARE
PROGGED TO BE DRY THROUGH TOMORROW AND EARLY INTO TUESDAY. WITH
FAIRLY ABUNDANT MOISTURE AND A RIDGE BUILDING OVERHEAD...FOG WILL
SPILL OVER FROM THE SEA AND ALSO DEVELOP ALONG SOME INLAND AREAS
TONIGHT. THE ALEUTIAN LOW THAT IS SOUTH OF SHEMYA WILL WORK
EAST/NORTHEAST AND WILL EVENTUALLY BRING SHOWERS SPREADING FROM
WEST TO EAST TO THE AREA.

BERING SEA/ALEUTIANS...
THE SUMMERTIME RIDGE WITH THE TYPICAL FOG AND STRATUS WILL
CONTINUE. A SHORTWAVE RIDGE AND THE ABUNDANT MOISTURE PLUME TO THE
SOUTH ARE HELPING TO PUSH AND ENHANCEMENT NOTED IN SATELLITE
IMAGERY NORTH BETWEEN ATKA AND DUTCH. GIVEN THE LACK OF
OBSERVATIONS/GROUND TRUTH...IT IS ASSUMED THAT THERE IS SOME RAIN
COMING OUT OF THIS FEATURE. ALL GUIDANCE TAKES THIS WAVE AND
WEAKENS IT AS IT WORKS NORTH THROUGH THE PRIBS...BRINGING THE NEXT
CHANCE OF RAIN INTO THE EVENING HOURS...WHICH IS JUST A LITTLE MORE
THAN THE -DZ THAT AS BEEN EVER PRESENT. THE LOW SOUTH OF SHEMYA
WILL THEN SLOWLY WORK EAST THROUGH THE BEGINNING OF THE
WEEK...BRINGING RAIN/CLOUD CHANCES EAST AND TOWARDS THE AKPEN BY
MIDWEEK.

&&

.LONG TERM FORECAST...
THE SECOND HALF OF THE WEEK WILL SEE A PERSISTENT UPPER LEVEL LOW
OVER THE GULF OF ALASKA WITH A TROUGH EXTENDING OVER SOUTH CENTRAL
THROUGH THE INTERIOR. THIS TROUGH AND LOW WILL SLOWLY MOVE
EASTWARD AS A LARGE UPPER LEVEL HIGH IN THE WESTERN BERING SEA
WEDNESDAY MOVES EASTWARD THROUGH THE REST OF THE WEEK. THERE WAS A
LITTLE BIT OF UNCERTAINTY YESTERDAY HOW STRONG THIS RIDGE WILL BE
AND HOW FAR EAST IT WILL MOVE BY NEXT WEEKEND. CONFIDENCE IS NOW
INCREASING THAT THIS RIDGE WILL BE SUFFICIENTLY STRONG TO DISLODGE
THE PERSISTENT LOW IN THE GULF AND BECOME THE MAIN WEATHER FEATURE
NEXT WEEKEND THROUGH EARLY NEXT WEEK. IN SOUTHCENTRAL THIS PATTERN
SHOULD TRANSLATE TO AFTERNOON AND EVENING SHOWERS...ESPECIALLY
OVER ELEVATED TERRAIN...IN THE MIDDLE OF THE WEEK WITH LESS SEEN
EACH DAY UNTIL THERE ARE NOT TOO MANY AROUND BY SATURDAY. THE ONE
SIGNIFICANT CONCERN TO WATCH TOWARD NEXT WEEKEND CONCERNING THIS
RIDGE IS THAT THERE IS STILL SOME COLD UPPER LEVEL LOWS LURKING
AROUND IN THE ARCTIC OCEAN. SHOULD ONE OR MORE OF THESE COLD LOWS
RIDE DOWN THE EASTERN SIDE OF THE RIDGE THEY COULD BRING A PERIOD
OF RAINFALL...AND THEN RAPIDLY CLEAR OUT AGAIN. IN SOUTHWEST
ALASKA THE SHOWERS OVER ELEVATED TERRAIN SHOULD BE MOSTLY OVER
AFTER THURSDAY. HOWEVER THE COASTAL AREAS WILL BE AT RISK FOR LOW
CLOUDS AND FOG AS THERE WILL LIKELY BE WIDESPREAD STRATUS OVER THE
BERING SEA UNDER THIS RIDGE.

&&

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

$$

SHEA/EZ JUL 14





000
FXAK68 PAFC 201342
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
542 AM AKDT SUN JUL 20 2014

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL LOW THAT ENTERED THE NORTHWEST COAST EARLY
YESTERDAY MORNING HAS NOW MOVED TO THE SOUTHEAST AND HAS NOW
BECOME A SHARP TROUGH OVER THE SOUTH MAINLAND. THIS SYSTEM HAS
BROUGHT WIDESPREAD RAIN...WHICH HAS BEEN QUITE HEAVY AT TIMES
OVERNIGHT...TO MUCH OF SOUTHCENTRAL. THE STRONG JET ASSOCIATED
WITH THIS SYSTEM CAN BE SEEN WELL ON WATER VAPOR IMAGERY
STRETCHING FROM THE WESTERN INTERIOR TO THE WESTERN GULF. THIS JET
WILL CONTINUE DIGGING THE TROUGH OVER THE COURSE OF THIS
MORNING...EVENTUALLY CAUSING IT TO DETACH FROM THE PRIMARY ARCTIC
LOW AND MOVE INTO THE NORTHERN GULF IN THE AFTERNOON. TO THE WEST
OF THIS UPPER LOW...A RIDGE OF HIGH PRESSURE STRETCHES FROM THE
EASTERN ALEUTIANS/AKPENN INTO THE WESTERN BERING. THIS RIDGE IS
SLOWLY BUILD TO THE EAST BEHIND THE DEPARTING LOW...AND WILL HELP
TO CLEAR OUT MUCH OF THE SOUTHERN MAINLAND BY THIS EVENING. A WEAK
LOW IS APPROACHING THE CENTRAL ALEUTIANS IS BEGINNING TO SPREAD
RAIN TO THE ADAK AREA. THIS SYSTEM WILL BRING LIGHT RAIN INTO THE
EASTERN ALEUTIANS IS IT CONTINUES TRACKING TO NORTHEAST AND
WEAKENING.

&&

.MODEL DISCUSSION...
WHILE THE MODELS REMAIN IN GREAT SYNOPTIC AGREEMENT THROUGH THE
SHORT TERM...THEY CONTINUE TO HAVE MAJOR ISSUES WITH DEPICTING THE
RAIN CURRENTLY FALLING OVER SOUTHCENTRAL. THE 00Z GFS DID AN
ACCEPTABLE JOB AT CAPTURING THE RAINFALL OVER THE SUSITNA
VALLEY...BUT THE LATEST 06Z RUN HAS COME MORE IN LINE WITH THE
REST OF THE MODELS BY KEEPING THE RAINFALL TOO FAR TO THE EAST.
THIS SHOULD HOWEVER ONLY HAVE AN IMPACT TO TIMING EXACTLY WHEN THE
RAIN WILL END OVER SOUTHCENTRAL. THERE STILL IS GOOD CONFIDENCE IN
THE GENERAL TREND OF IMPROVING CONDITIONS FROM THE WEST OVER THE
COURSE OF THIS MORNING. OTHERWISE...AS MENTIONED ABOVE THERE
REMAINS GREAT AGREEMENT WITH THE MOVEMENT OF THE TRANSITORY RIDGE
MOVING OVER THE MAINLAND LATER TODAY...AND SLIGHTLY LESS AGREEMENT
WITH THE THE PROGRESSION OF THE ALEUTIAN LOW IS IT BECOMES
ABSORBED IN THE NEXT WAVE ENTERING THE WEST MAINLAND LATE TUESDAY.


&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...THE RAIN CURRENTLY FALLING FROM ANCHORAGE
NORTHWARD INTO THE MATANUSKA VALLEY AND EASTERN SUSITNA VALLEY
WILL BEGIN TO DIMINISH FROM WEST TO EAST BY LATE MORNING AS THE
UPPER TROUGH CONTINUES TO CUTOFF FROM THE PRIMARY LOW AND DRIFT
INTO THE NORTHERN GULF. AREAS FURTHER EAST WILL REMAIN CLOUDY AND
RAINY FOR A MAJORITY OF THE DAY...BUT THEN CLEAR OUT RAPIDLY
THIS EVENING AS OFFSHORE FLOW TAKES OVER THROUGHOUT THE SOUTH
MAINLAND. THIS TREND WILL THEN CONTINUE INTO MONDAY...CAUSING THE
ENTIRE AREA TO HAVE A CLEAR AND DRY START TO THE WEEK. GUSTY
OFFSHORE WINDS WILL FORM ALONG THE GULF COAST OF THE KENAI
PENINSULA TODAY (ESPECIALLY NEAR SEWARD AND WHITTIER) DUE TO
PRESSURE FALLS AND GOOD JET SUPPORT REMAINING OVER THE AREA.
CLOUDY SKIES WITH A CHANCE OF RAIN WILL THEN RETURN LATE TUESDAY
AS YET ANOTHER WAVE APPROACHES THE AREA FROM THE WEST COAST.

SOUTHWEST ALASKA...WITH THE EXCEPTION OF THE STRAY RAIN SHOWERS
OVER THE ALASKA AND ALEUTIAN RANGES THIS MORNING...THE SOUTHWEST
MAINLAND WILL REMAIN DRY UNTIL TUESDAY. CLOUDS WILL RAPIDLY
DIMINISH LATE THIS MORNING AS RIDGING OVER THE BERING BUILDS OVER
THE WEST COAST. THIS WILL PRODUCE A CHANCE OF DIURNAL FOG
OVERNIGHT TONIGHT...ESPECIALLY FOR COASTAL BRISTOL BAY AND THE
DELTA DUE TO AN ALREADY MOISTENED BOUNDARY LAYER FROM RECENT
RAINS. THIS STRETCH OF GOOD WEATHER HOWEVER LOOKS TO BE VERY SHORT
LIVED...AS THE NEXT BAND OF RAIN BEGIN TO ENTER THE WEST COAST
LATE MONDAY NIGHT AND SPREAD THROUGHOUT THE AREA FOR TUESDAY.

BERING SEA/ALEUTIANS...THE NORTH PACIFIC LOW CURRENTLY APPROACHING
THE ALEUTIANS WILL BRING THE NEXT CHANCE OF RAIN TO THE CENTRAL
ALEUTIANS. THIS LOW WILL THEN MOVE INTO THE EASTERN ALEUTIANS AND
BECOMING ABSORBED INTO ANOTHER TROUGH DESCENDING ONTO THE WEST
COAST ON TUESDAY...KEEPING THE AREAS FROM DUTCH HARBOR EAST CLOUDY
WITH A CHANCE OF RAIN INTO WEDNESDAY.


&&

.LONG TERM FORECAST...
THERE CONTINUES TO BE GOOD AGREEMENT THAT THE ELONGATED WAVE THAT
WILL MOVE OVER THE MAINLAND ON TUESDAY WILL BECOME A NEARLY
STATIONARY CUTOFF LOW OVER THE NORTHERN GULF ON WEDNESDAY. THIS
IS SLIGHTLY FURTHER NORTH THAN THE MODELS HAD BEEN DEPICTING
YESTERDAY...AND SHOULD KEEP MUCH OF THE SOUTH MAINLAND CLOUDY WITH
A RISK OF SHOWERS UNTIL LATER IN THE WEEK. A BERING RIDGE WILL
THEN LOOKS TO ONCE AGAIN BUILD OVER THE WESTERN MAINLAND ON
FRIDAY...AND SPREAD INTO THE SOUTH MAINLAND FOR THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 120 130 131.
FIRE WEATHER...NONE.

&&

$$

DEK JUL 14




000
FXAK68 PAFC 201342
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
542 AM AKDT SUN JUL 20 2014

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL LOW THAT ENTERED THE NORTHWEST COAST EARLY
YESTERDAY MORNING HAS NOW MOVED TO THE SOUTHEAST AND HAS NOW
BECOME A SHARP TROUGH OVER THE SOUTH MAINLAND. THIS SYSTEM HAS
BROUGHT WIDESPREAD RAIN...WHICH HAS BEEN QUITE HEAVY AT TIMES
OVERNIGHT...TO MUCH OF SOUTHCENTRAL. THE STRONG JET ASSOCIATED
WITH THIS SYSTEM CAN BE SEEN WELL ON WATER VAPOR IMAGERY
STRETCHING FROM THE WESTERN INTERIOR TO THE WESTERN GULF. THIS JET
WILL CONTINUE DIGGING THE TROUGH OVER THE COURSE OF THIS
MORNING...EVENTUALLY CAUSING IT TO DETACH FROM THE PRIMARY ARCTIC
LOW AND MOVE INTO THE NORTHERN GULF IN THE AFTERNOON. TO THE WEST
OF THIS UPPER LOW...A RIDGE OF HIGH PRESSURE STRETCHES FROM THE
EASTERN ALEUTIANS/AKPENN INTO THE WESTERN BERING. THIS RIDGE IS
SLOWLY BUILD TO THE EAST BEHIND THE DEPARTING LOW...AND WILL HELP
TO CLEAR OUT MUCH OF THE SOUTHERN MAINLAND BY THIS EVENING. A WEAK
LOW IS APPROACHING THE CENTRAL ALEUTIANS IS BEGINNING TO SPREAD
RAIN TO THE ADAK AREA. THIS SYSTEM WILL BRING LIGHT RAIN INTO THE
EASTERN ALEUTIANS IS IT CONTINUES TRACKING TO NORTHEAST AND
WEAKENING.

&&

.MODEL DISCUSSION...
WHILE THE MODELS REMAIN IN GREAT SYNOPTIC AGREEMENT THROUGH THE
SHORT TERM...THEY CONTINUE TO HAVE MAJOR ISSUES WITH DEPICTING THE
RAIN CURRENTLY FALLING OVER SOUTHCENTRAL. THE 00Z GFS DID AN
ACCEPTABLE JOB AT CAPTURING THE RAINFALL OVER THE SUSITNA
VALLEY...BUT THE LATEST 06Z RUN HAS COME MORE IN LINE WITH THE
REST OF THE MODELS BY KEEPING THE RAINFALL TOO FAR TO THE EAST.
THIS SHOULD HOWEVER ONLY HAVE AN IMPACT TO TIMING EXACTLY WHEN THE
RAIN WILL END OVER SOUTHCENTRAL. THERE STILL IS GOOD CONFIDENCE IN
THE GENERAL TREND OF IMPROVING CONDITIONS FROM THE WEST OVER THE
COURSE OF THIS MORNING. OTHERWISE...AS MENTIONED ABOVE THERE
REMAINS GREAT AGREEMENT WITH THE MOVEMENT OF THE TRANSITORY RIDGE
MOVING OVER THE MAINLAND LATER TODAY...AND SLIGHTLY LESS AGREEMENT
WITH THE THE PROGRESSION OF THE ALEUTIAN LOW IS IT BECOMES
ABSORBED IN THE NEXT WAVE ENTERING THE WEST MAINLAND LATE TUESDAY.


&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...THE RAIN CURRENTLY FALLING FROM ANCHORAGE
NORTHWARD INTO THE MATANUSKA VALLEY AND EASTERN SUSITNA VALLEY
WILL BEGIN TO DIMINISH FROM WEST TO EAST BY LATE MORNING AS THE
UPPER TROUGH CONTINUES TO CUTOFF FROM THE PRIMARY LOW AND DRIFT
INTO THE NORTHERN GULF. AREAS FURTHER EAST WILL REMAIN CLOUDY AND
RAINY FOR A MAJORITY OF THE DAY...BUT THEN CLEAR OUT RAPIDLY
THIS EVENING AS OFFSHORE FLOW TAKES OVER THROUGHOUT THE SOUTH
MAINLAND. THIS TREND WILL THEN CONTINUE INTO MONDAY...CAUSING THE
ENTIRE AREA TO HAVE A CLEAR AND DRY START TO THE WEEK. GUSTY
OFFSHORE WINDS WILL FORM ALONG THE GULF COAST OF THE KENAI
PENINSULA TODAY (ESPECIALLY NEAR SEWARD AND WHITTIER) DUE TO
PRESSURE FALLS AND GOOD JET SUPPORT REMAINING OVER THE AREA.
CLOUDY SKIES WITH A CHANCE OF RAIN WILL THEN RETURN LATE TUESDAY
AS YET ANOTHER WAVE APPROACHES THE AREA FROM THE WEST COAST.

SOUTHWEST ALASKA...WITH THE EXCEPTION OF THE STRAY RAIN SHOWERS
OVER THE ALASKA AND ALEUTIAN RANGES THIS MORNING...THE SOUTHWEST
MAINLAND WILL REMAIN DRY UNTIL TUESDAY. CLOUDS WILL RAPIDLY
DIMINISH LATE THIS MORNING AS RIDGING OVER THE BERING BUILDS OVER
THE WEST COAST. THIS WILL PRODUCE A CHANCE OF DIURNAL FOG
OVERNIGHT TONIGHT...ESPECIALLY FOR COASTAL BRISTOL BAY AND THE
DELTA DUE TO AN ALREADY MOISTENED BOUNDARY LAYER FROM RECENT
RAINS. THIS STRETCH OF GOOD WEATHER HOWEVER LOOKS TO BE VERY SHORT
LIVED...AS THE NEXT BAND OF RAIN BEGIN TO ENTER THE WEST COAST
LATE MONDAY NIGHT AND SPREAD THROUGHOUT THE AREA FOR TUESDAY.

BERING SEA/ALEUTIANS...THE NORTH PACIFIC LOW CURRENTLY APPROACHING
THE ALEUTIANS WILL BRING THE NEXT CHANCE OF RAIN TO THE CENTRAL
ALEUTIANS. THIS LOW WILL THEN MOVE INTO THE EASTERN ALEUTIANS AND
BECOMING ABSORBED INTO ANOTHER TROUGH DESCENDING ONTO THE WEST
COAST ON TUESDAY...KEEPING THE AREAS FROM DUTCH HARBOR EAST CLOUDY
WITH A CHANCE OF RAIN INTO WEDNESDAY.


&&

.LONG TERM FORECAST...
THERE CONTINUES TO BE GOOD AGREEMENT THAT THE ELONGATED WAVE THAT
WILL MOVE OVER THE MAINLAND ON TUESDAY WILL BECOME A NEARLY
STATIONARY CUTOFF LOW OVER THE NORTHERN GULF ON WEDNESDAY. THIS
IS SLIGHTLY FURTHER NORTH THAN THE MODELS HAD BEEN DEPICTING
YESTERDAY...AND SHOULD KEEP MUCH OF THE SOUTH MAINLAND CLOUDY WITH
A RISK OF SHOWERS UNTIL LATER IN THE WEEK. A BERING RIDGE WILL
THEN LOOKS TO ONCE AGAIN BUILD OVER THE WESTERN MAINLAND ON
FRIDAY...AND SPREAD INTO THE SOUTH MAINLAND FOR THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 120 130 131.
FIRE WEATHER...NONE.

&&

$$

DEK JUL 14





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