Home > Products > Valid Products > AFD

000
FXAK68 PAFC 281325
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
525 AM AKDT TUE APR 28 2015

.ANALYSIS AND UPPER LEVELS...

AN UPPER LEVEL LOW OVER THE GULF OF ALASKA CONTINUES TO SLOWLY
TRACK EASTWARD...WITH A BROAD UPPER LOW OVER THE WESTERN AND
CENTRAL BERING SEA. AT THE SURFACE...THERE IS A SURFACE LOW
ENTERING THE CENTRAL ALEUTIANS WITH AN ASSOCIATED FRONT TRACKING
THROUGH THE NORTHERN AND EASTERN BERING. STRONG WESTERLY FLOW
ALOFT OVER THE NORTH PACIFIC HAS KEPT THE SYSTEMS MOVING QUICKLY
THROUGH THE AREA. LOW CEILINGS AND FOG PERSIST OVER THE EASTERN
BERING...AND HAS STARTED TO PUSH INLAND INTO THE BRISTOL BAY
AREA OVERNIGHT.

&&

.MODEL DISCUSSION...

MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT THROUGH TOMORROW
EVENING...WITH THE HIGH RESOLUTIONS MODELS (00Z GEM MAINLY) BEING
THE PREFERRED SOLUTION REGARDING THE SYSTEM MOVING THROUGH THE
GULF AND THE SYSTEM OVER THE BERING THAT CROSSES THE EASTERN
ALEUTIANS TOMORROW NIGHT. THERE ARE SOME TIMING AND INTENSITY
DISCREPANCIES WITH REGARDS TO THE WEAK DISTURBANCES ROTATING
AROUND THE UPPER LOWS. THESE DISTURBANCES ARE FAIRLY WEAK AND
MAINLY AFFECT THE TIMING OF INCREASING/DECREASING SHOWER
ACTIVITY...WHICH IS FAIRLY EASY TO HANDLE. FORECAST CONFIDENCE IS
A LITTLE HIGHER THAN NORMAL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

LINGERING RAIN SHOWERS (AND SNOW SHOWERS IN THE COPPER RIVER
VALLEY) WILL DISSIPATE THIS MORNING AS A STRONG AND FAST-MOVING
LOW PRESSURE SYSTEM RACES NORTHWARD THROUGH THE PANHANDLE. THIS
NEW SYSTEM WILL CONSOLIDATE MUCH OF THE ATMOSPHERIC ENERGY AND
MOISTURE TO THE EAST OF OUR FORECAST AREA TODAY...WHICH SHOULD
RESULT IN SOME PARTIAL CLEARING/SUNNY BREAKS FOR MOST AREAS AS THE
DAY PROGRESSES. A SHORT-LIVED BUT MODERATELY STRONG COASTAL GAP
WIND EVENT WILL ALSO OCCUR THROUGH THIS EVENING AS OFFSHORE PRESSURE
GRADIENTS TIGHTEN RAPIDLY DUE TO THE PANHANDLE STORM.
WHITTIER/PASSAGE CANAL HAS ALREADY STARTED TO SEE SOME
GUSTS...WITH THE FAVORED AREAS AROUND PRINCE WILLIAM SOUND AND THE
EASTERN KENAI ALL GETTING IN ON THE ACT BY LATE THIS MORNING. GAP
WINDS WILL COME DOWN RAPIDLY LATE THIS AFTERNOON OR EARLY THIS
EVENING AS THE SURFACE LOW CENTER BLASTS RAPIDLY ACROSS THE
NORTHERN GULF AND STALLS IN THE VICINITY OF THE SOUTHERN KENAI
PENINSULA...RE-ORIENTATING THE PRESSURE GRADIENT. WITH SOME
SUNSHINE AND OFFSHORE FLOW...TEMPERATURES SHOULD CLIMB INTO THE
MID TO UPPER 50S AGAIN FOR MOST AREAS...INCLUDING VALDEZ/SEWARD
AREAS WHERE THE MODERATING EFFECT OF A SEA BREEZE WILL BE LARGELY
OR TOTALLY NEGATED TODAY.

MEANWHILE...DIURNAL INSTABILITY WILL LIKELY LEAD TO THE
DEVELOPMENT OF SHOWER ACTIVITY ACROSS THE COPPER BASIN AGAIN THIS
AFTERNOON THAT WILL GENERALLY SPREAD WESTWARD WITH TIME OVERNIGHT
TONIGHT. MODELS ARE TRYING TO KEEP ANCHORAGE ALMOST TOTALLY DRY
THROUGH MIDWEEK...BUT WITH A DECENTLY STRONG RESIDUAL SHORTWAVE
MOVING IN FROM THE EAST TONIGHT IT DOES SEEM PLAUSIBLE THAT THE
AFOREMENTIONED SHOWER ACTIVITY WILL HOLD TOGETHER ACROSS THE
CHUGACH MOUNTAINS. THUS WILL KEEP SLIGHT CHANCE POPS AROUND UPPER
COOK INLET AS EARLY AS THIS EVENING. BY WEDNESDAY...THE AREA WILL
BE UNDER THE INFLUENCE OF GENERAL CYCLONIC FLOW BUT WEAK OVERALL
FEATURES. THIS SHOULD LEAD TO A FAIRLY MESSY PATTERN IN WHICH IT
IS HARD TO NAIL DOWN WHERE SHOWER ACTIVITY IS LIKELY TO FOCUS. AS
A RESULT...HAVE ADOPTED A BIT MORE BROAD-BRUSHED PRECIPITATION
FORECAST FOR THE WEDNESDAY/WEDNESDAY NIGHT TIME-FRAMES THAN
TYPICALLY LIKE TO DO. DESPITE THE LARGE AREAS OF LOW POPS...OVERALL
CONDITIONS SHOULD REMAIN RATHER CLOUDY BUT FOR THE MOST PART DRY
THROUGH THURSDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
RELATIVELY CLEAR SKIES AND INSTABILITY WILL LEAD TO SHOWERS
DEVELOPING ALONG THE ALASKA RANGE...PRIMARILY IN THE AFTERNOON
AND EVENING. AT THIS TIME CONDITIONS DO NOT LOOK IDEAL FOR
THUNDERSTORM DEVELOPMENT. THESE UNSTABLE CONDITIONS LOOK TO LAST
INTO WEDNESDAY. THE OTHER MAIN ISSUE IS THE MARINE LAYER ALONG
THE COAST THAT IS BRINGING STRATUS AND FOG TO COASTAL COMMUNITIES.
HOWEVER...FLOW WILL BECOME MORE OFFSHORE THIS EVENING PUSHING THE
MARINE LAYER AWAY FROM THE SOUTHWEST.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE LOW IN THE SOUTHERN BERING WILL CONTINUE ITS EASTERLY TRACK
BRINGING MORE SHOWERS TO THE ALEUTIANS AS IT PASSES. BY WEDNESDAY
MORNING IT WILL HAVE MOVED INTO THE GULF LEAVING NORTHWESTERLY
FLOW OVER MUCH OF THE BERING AND ALEUTIANS. THIS WILL RESULT IN
LIGHT SHOWERS FOR THE ISLANDS.

&&

.LONG TERM FORECAST (DAY 3 THROUGH 7)...
THE STRONG ZONAL JET STREAM OVER THE ALEUTIAN CHAIN CONTINUES TO
TRACK EASTWARD HEADING INTO THE WEEKEND. THERE WILL BE A BROAD
AREA OF LOW PRESSURE IN BERING SEA THAT WILL WEAKEN INTO A TROUGH
THROUGH FRIDAY. BY SATURDAY A NORTH PACIFIC LOW WILL TRACK INTO
THE WESTERN GULF AND BE LOCATED IN THE CENTRAL ALEUTIANS BY
SUNDAY. THIS WILL BRING WARMER TEMPERATURES AND BE ACCOMPANIED BY
RAIN AND GUSTY SOUTHERLY WINDS.

THE GULF WILL HAVE SOUTH TO SOUTHWESTERLY FLOW WITH WEAK
DISTURBANCES MOVING INTO THE AREA THROUGH FRIDAY. THESE SYNOPTIC
FEATURES WILL BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG THE
COASTAL AREAS FOR THE NEXT SEVERAL DAYS. BY THURSDAY AN UPPER
LEVEL RIDGE BUILDS INTO THE WESTERN GULF. THIS RIDGE WILL BECOME
AMPLIFIED AND BE POSITIONED OVER THE SOUTHCENTRAL REGION EXTENDING
INTO MATSU VALLEY BY FRIDAY THROUGH THE WEEKEND. THIS SYNOPTIC
FEATURE WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS TO THE
SOUTHCENTRAL REGION. THERE WILL BE A THERMAL TROUGH SETTING UP
OVER THE WEEKEND...WHICH WILL INCREASE THE CHANCES FOR AFTERNOON
TO EVENING SHOWERY ACTIVITY FOR THE INLAND AREAS. THE MODELS WERE
IN BETTER AGREEMENT WITH THE TIMING AND PLACEMENT OF THE DIFFERENT
SYNOPTIC FEATURES...WITH HPC USING A BLEND OF THE ENSEMBLE MEANS
THROUGH THE WEEKEND.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES...174 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...TP
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...PD/MMC





000
FXAK68 PAFC 281325
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
525 AM AKDT TUE APR 28 2015

.ANALYSIS AND UPPER LEVELS...

AN UPPER LEVEL LOW OVER THE GULF OF ALASKA CONTINUES TO SLOWLY
TRACK EASTWARD...WITH A BROAD UPPER LOW OVER THE WESTERN AND
CENTRAL BERING SEA. AT THE SURFACE...THERE IS A SURFACE LOW
ENTERING THE CENTRAL ALEUTIANS WITH AN ASSOCIATED FRONT TRACKING
THROUGH THE NORTHERN AND EASTERN BERING. STRONG WESTERLY FLOW
ALOFT OVER THE NORTH PACIFIC HAS KEPT THE SYSTEMS MOVING QUICKLY
THROUGH THE AREA. LOW CEILINGS AND FOG PERSIST OVER THE EASTERN
BERING...AND HAS STARTED TO PUSH INLAND INTO THE BRISTOL BAY
AREA OVERNIGHT.

&&

.MODEL DISCUSSION...

MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT THROUGH TOMORROW
EVENING...WITH THE HIGH RESOLUTIONS MODELS (00Z GEM MAINLY) BEING
THE PREFERRED SOLUTION REGARDING THE SYSTEM MOVING THROUGH THE
GULF AND THE SYSTEM OVER THE BERING THAT CROSSES THE EASTERN
ALEUTIANS TOMORROW NIGHT. THERE ARE SOME TIMING AND INTENSITY
DISCREPANCIES WITH REGARDS TO THE WEAK DISTURBANCES ROTATING
AROUND THE UPPER LOWS. THESE DISTURBANCES ARE FAIRLY WEAK AND
MAINLY AFFECT THE TIMING OF INCREASING/DECREASING SHOWER
ACTIVITY...WHICH IS FAIRLY EASY TO HANDLE. FORECAST CONFIDENCE IS
A LITTLE HIGHER THAN NORMAL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

LINGERING RAIN SHOWERS (AND SNOW SHOWERS IN THE COPPER RIVER
VALLEY) WILL DISSIPATE THIS MORNING AS A STRONG AND FAST-MOVING
LOW PRESSURE SYSTEM RACES NORTHWARD THROUGH THE PANHANDLE. THIS
NEW SYSTEM WILL CONSOLIDATE MUCH OF THE ATMOSPHERIC ENERGY AND
MOISTURE TO THE EAST OF OUR FORECAST AREA TODAY...WHICH SHOULD
RESULT IN SOME PARTIAL CLEARING/SUNNY BREAKS FOR MOST AREAS AS THE
DAY PROGRESSES. A SHORT-LIVED BUT MODERATELY STRONG COASTAL GAP
WIND EVENT WILL ALSO OCCUR THROUGH THIS EVENING AS OFFSHORE PRESSURE
GRADIENTS TIGHTEN RAPIDLY DUE TO THE PANHANDLE STORM.
WHITTIER/PASSAGE CANAL HAS ALREADY STARTED TO SEE SOME
GUSTS...WITH THE FAVORED AREAS AROUND PRINCE WILLIAM SOUND AND THE
EASTERN KENAI ALL GETTING IN ON THE ACT BY LATE THIS MORNING. GAP
WINDS WILL COME DOWN RAPIDLY LATE THIS AFTERNOON OR EARLY THIS
EVENING AS THE SURFACE LOW CENTER BLASTS RAPIDLY ACROSS THE
NORTHERN GULF AND STALLS IN THE VICINITY OF THE SOUTHERN KENAI
PENINSULA...RE-ORIENTATING THE PRESSURE GRADIENT. WITH SOME
SUNSHINE AND OFFSHORE FLOW...TEMPERATURES SHOULD CLIMB INTO THE
MID TO UPPER 50S AGAIN FOR MOST AREAS...INCLUDING VALDEZ/SEWARD
AREAS WHERE THE MODERATING EFFECT OF A SEA BREEZE WILL BE LARGELY
OR TOTALLY NEGATED TODAY.

MEANWHILE...DIURNAL INSTABILITY WILL LIKELY LEAD TO THE
DEVELOPMENT OF SHOWER ACTIVITY ACROSS THE COPPER BASIN AGAIN THIS
AFTERNOON THAT WILL GENERALLY SPREAD WESTWARD WITH TIME OVERNIGHT
TONIGHT. MODELS ARE TRYING TO KEEP ANCHORAGE ALMOST TOTALLY DRY
THROUGH MIDWEEK...BUT WITH A DECENTLY STRONG RESIDUAL SHORTWAVE
MOVING IN FROM THE EAST TONIGHT IT DOES SEEM PLAUSIBLE THAT THE
AFOREMENTIONED SHOWER ACTIVITY WILL HOLD TOGETHER ACROSS THE
CHUGACH MOUNTAINS. THUS WILL KEEP SLIGHT CHANCE POPS AROUND UPPER
COOK INLET AS EARLY AS THIS EVENING. BY WEDNESDAY...THE AREA WILL
BE UNDER THE INFLUENCE OF GENERAL CYCLONIC FLOW BUT WEAK OVERALL
FEATURES. THIS SHOULD LEAD TO A FAIRLY MESSY PATTERN IN WHICH IT
IS HARD TO NAIL DOWN WHERE SHOWER ACTIVITY IS LIKELY TO FOCUS. AS
A RESULT...HAVE ADOPTED A BIT MORE BROAD-BRUSHED PRECIPITATION
FORECAST FOR THE WEDNESDAY/WEDNESDAY NIGHT TIME-FRAMES THAN
TYPICALLY LIKE TO DO. DESPITE THE LARGE AREAS OF LOW POPS...OVERALL
CONDITIONS SHOULD REMAIN RATHER CLOUDY BUT FOR THE MOST PART DRY
THROUGH THURSDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
RELATIVELY CLEAR SKIES AND INSTABILITY WILL LEAD TO SHOWERS
DEVELOPING ALONG THE ALASKA RANGE...PRIMARILY IN THE AFTERNOON
AND EVENING. AT THIS TIME CONDITIONS DO NOT LOOK IDEAL FOR
THUNDERSTORM DEVELOPMENT. THESE UNSTABLE CONDITIONS LOOK TO LAST
INTO WEDNESDAY. THE OTHER MAIN ISSUE IS THE MARINE LAYER ALONG
THE COAST THAT IS BRINGING STRATUS AND FOG TO COASTAL COMMUNITIES.
HOWEVER...FLOW WILL BECOME MORE OFFSHORE THIS EVENING PUSHING THE
MARINE LAYER AWAY FROM THE SOUTHWEST.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE LOW IN THE SOUTHERN BERING WILL CONTINUE ITS EASTERLY TRACK
BRINGING MORE SHOWERS TO THE ALEUTIANS AS IT PASSES. BY WEDNESDAY
MORNING IT WILL HAVE MOVED INTO THE GULF LEAVING NORTHWESTERLY
FLOW OVER MUCH OF THE BERING AND ALEUTIANS. THIS WILL RESULT IN
LIGHT SHOWERS FOR THE ISLANDS.

&&

.LONG TERM FORECAST (DAY 3 THROUGH 7)...
THE STRONG ZONAL JET STREAM OVER THE ALEUTIAN CHAIN CONTINUES TO
TRACK EASTWARD HEADING INTO THE WEEKEND. THERE WILL BE A BROAD
AREA OF LOW PRESSURE IN BERING SEA THAT WILL WEAKEN INTO A TROUGH
THROUGH FRIDAY. BY SATURDAY A NORTH PACIFIC LOW WILL TRACK INTO
THE WESTERN GULF AND BE LOCATED IN THE CENTRAL ALEUTIANS BY
SUNDAY. THIS WILL BRING WARMER TEMPERATURES AND BE ACCOMPANIED BY
RAIN AND GUSTY SOUTHERLY WINDS.

THE GULF WILL HAVE SOUTH TO SOUTHWESTERLY FLOW WITH WEAK
DISTURBANCES MOVING INTO THE AREA THROUGH FRIDAY. THESE SYNOPTIC
FEATURES WILL BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG THE
COASTAL AREAS FOR THE NEXT SEVERAL DAYS. BY THURSDAY AN UPPER
LEVEL RIDGE BUILDS INTO THE WESTERN GULF. THIS RIDGE WILL BECOME
AMPLIFIED AND BE POSITIONED OVER THE SOUTHCENTRAL REGION EXTENDING
INTO MATSU VALLEY BY FRIDAY THROUGH THE WEEKEND. THIS SYNOPTIC
FEATURE WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS TO THE
SOUTHCENTRAL REGION. THERE WILL BE A THERMAL TROUGH SETTING UP
OVER THE WEEKEND...WHICH WILL INCREASE THE CHANCES FOR AFTERNOON
TO EVENING SHOWERY ACTIVITY FOR THE INLAND AREAS. THE MODELS WERE
IN BETTER AGREEMENT WITH THE TIMING AND PLACEMENT OF THE DIFFERENT
SYNOPTIC FEATURES...WITH HPC USING A BLEND OF THE ENSEMBLE MEANS
THROUGH THE WEEKEND.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES...174 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...TP
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...PD/MMC




000
FXAK68 PAFC 280028
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
428 PM AKDT MON APR 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE GULF OF ALASKA. THERE IS A
DISSIPATING LOW OVER THE CENTRAL BERING SEA WITH A WEAK FRONT
STRETCHING EASTWARD ACROSS THE PRIBILOFS AND THEN SOUTHEAST TO
THE WESTERN ALASKA PENINSULA. THERE IS A STRENGTHENING LOW MOVING
INTO THE WESTERN ALEUTIANS FROM THE WEST. STRONG WESTERLY FLOW
ALOFT IS PUSHING ACROSS THE NORTH PACIFIC TO THE SOUTH OF THESE
LOWS. WEAK CYCLONIC FLOW EXISTS TO THE NORTH...COVERING MOST OF
SOUTHERN ALASKA AND THE BERING SEA. A WEAK RIDGE IS OVER THE
BERING STRAIT AND NORTHERN MAINLAND ALASKA. AT THE SURFACE THE
FLOW IS FAIRLY WEAK OVER LAND...WITH A BIT OF A THERMAL TROUGH
OVER CENTRAL ALASKA. HUMIDITIES IN SOUTH CENTRAL HAVE INCREASED
CONSIDERABLY TODAY AND AS A RESULT THERE ARE NO FIRE WEATHER
CONCERNS.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THERE ARE OF COURSE SOME MINOR DIFFERENCES
IN THE TIMING OF IMPULSES AROUND THE UPPER LOWS. THESE IMPULSES
ARE FAIRLY WEAK AND MAINLY AFFECT THE TIMING OF INCREASING/DECREASING
SHOWER ACTIVITY...WHICH IS FAIRLY EASY TO HANDLE. FORECAST
CONFIDENCE IS A LITTLE HIGHER THAN NORMAL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A SUBTLE EASTERLY WAVE ALOFT IS SPREADING MOISTURE AND CLOUDS
OVER MOST OF MAINLAND SOUTHCENTRAL THIS EVENING. CONVECTIVE RAIN
SHOWERS ARE BREAKING OUT ACROSS THE SUSITNA VALLEY SOUTHWARD TO
THE KENAI PENINSULA. STEADIER AND MORE NUMEROUS RAIN AND SNOW
SHOWERS ARE IMPACTING THE COPPER BASIN AND THOMPSON PASS...WITH
LIGHT SNOW ACCUMULATION POSSIBLE THROUGH THE PASSES AND THE
WESTERN COPPER BASIN THROUGH TONIGHT. AN OFFSHORE PRESSURE
GRADIENT WILL DEVELOP ON TUESDAY...WITH DIMINISHING CLOUD COVER
AND SHOWERS. GUSTY GAP WINDS WILL ALSO DEVELOP ACROSS INLAND
COASTAL LOCATIONS. A WEAK LOW WILL TRACK OVER SOUTHCENTRAL
WEDNESDAY...WITH MORE CLOUDS AND SHOWERS REDEVELOPING OVER THE
MAINLAND. SOUTHEAST WINDS WILL BECOME GUSTY IN THE AFTERNOON...
ESPECIALLY ALONG TURNAGAIN ARM AND SOUTH AND WEST ANCHORAGE.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SOUTHWEST ALASKA IS UNDER A LARGE AREA OF MOSTLY CLEAR SKIES THIS
AFTERNOON WITH A FEW CLOUDS SNEAKING IN FROM THE EAST AS WELL AS
CUMULUS DEVELOPMENT OVER HIGHER ELEVATIONS. THE BIG QUESTION FOR
THIS EVENING IS WHETHER THERE WILL BE ENOUGH INSTABILITY TO
REALLY KICK OFF SHOWERS...AND EVEN THUNDERSTORMS IN THE KUSKOKWIM
VALLEY. THIS IS ONE OF THOSE CASES WHERE THE LINE BETWEEN MOSTLY
CLEAR SKIES AND HAVING QUITE A FEW SHOWERS AND EVEN THUNDERSTORMS
MAY BE QUITE THIN. WHILE SATELLITE IMAGERY SHOWS NOT MUCH IN THE
WAY OF CONVECTIVE BUILD UP SO FAR THEY COULD DEVELOP QUICKLY IF
THE CAPPING INVERSION BREAKS. MEANWHILE...STRATUS LURKING JUST
OFF THE COAST OF BRISTOL BAY WILL LIKELY COME ON SHORE AS THE
TEMPERATURES COOL OFF LATER THIS EVENING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE FIRST LOW IN THE BERING SEA LOCATED WEST OF THE PRIBILOF
ISLANDS IS ELONGATING AND WEAKENING AS IT PUSHES UP AGAINST THE
RIDGE OVER SOUTHWEST ALASKA. THE SECOND LOW TO THE WEST OF IT IS
TAPPING INTO JET SUPPORT AND IS STRENGTHENING IN THE WESTERN
ALEUTIANS. THIS WILL KEEP PRECIPITATION OVER THE BERING SEA AND
SOME GALES SOUTH OF THE ALEUTIANS THE NEXT FEW DAYS.

&&

.LONG TERM FORECAST (DAY 3 THROUGH 7)...
THE STRONG ZONAL JET STREAM OVER THE ALEUTIAN CHAIN CONTINUES TO
TRACK EASTWARD HEADING INTO THE WEEKEND. THERE WILL BE A BROAD
AREA OF LOW PRESSURE IN BERING SEA THAT WILL WEAKEN INTO A TROUGH
THROUGH FRIDAY. BY SATURDAY A NORTH PACIFIC LOW WILL TRACK INTO
THE WESTERN GULF WHILE ANOTHER LOW MOVES OUT OF ASIA AND INTO THE
BERING SEA.

THE GULF WILL HAVE SOUTH TO SOUTHWESTERLY FLOW WITH WEAK DISTURBANCES
MOVING INTO THE AREA THROUGH FRIDAY. THESE SYNOPTIC FEATURES WILL
BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG THE COASTAL AREAS
FOR THE NEXT SEVERAL DAYS. BY THURSDAY AN UPPER LEVEL RIDGE BUILDS
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED AND BE
POSITIONED OVER THE SOUTHCENTRAL REGION EXTENDING INTO MATSU VALLEY
FRIDAY THROUGH THE WEEKEND. THIS SYNOPTIC FEATURE WILL BRING WARMER
TEMPERATURES AND DRIER CONDITIONS TO THE SOUTHCENTRAL REGION. THERE
WILL BE A THERMAL TROUGH SETTING UP OVER THE WEEKEND...WHICH WILL
INCREASE THE CHANCES FOR AFTERNOON TO EVENING SHOWERY ACTIVITY FOR
THE INLAND AREAS. THE MODELS WERE IN BETTER AGREEMENT WITH THE
TIMING AND PLACEMENT OF THE DIFFERENT SYNOPTIC FEATURES...WITH WPC
USING A BLEND OF THE ENSEMBLE MEANS THROUGH THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 174 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...JA
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...EZ
LONG TERM...PD




000
FXAK68 PAFC 280028
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
428 PM AKDT MON APR 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE GULF OF ALASKA. THERE IS A
DISSIPATING LOW OVER THE CENTRAL BERING SEA WITH A WEAK FRONT
STRETCHING EASTWARD ACROSS THE PRIBILOFS AND THEN SOUTHEAST TO
THE WESTERN ALASKA PENINSULA. THERE IS A STRENGTHENING LOW MOVING
INTO THE WESTERN ALEUTIANS FROM THE WEST. STRONG WESTERLY FLOW
ALOFT IS PUSHING ACROSS THE NORTH PACIFIC TO THE SOUTH OF THESE
LOWS. WEAK CYCLONIC FLOW EXISTS TO THE NORTH...COVERING MOST OF
SOUTHERN ALASKA AND THE BERING SEA. A WEAK RIDGE IS OVER THE
BERING STRAIT AND NORTHERN MAINLAND ALASKA. AT THE SURFACE THE
FLOW IS FAIRLY WEAK OVER LAND...WITH A BIT OF A THERMAL TROUGH
OVER CENTRAL ALASKA. HUMIDITIES IN SOUTH CENTRAL HAVE INCREASED
CONSIDERABLY TODAY AND AS A RESULT THERE ARE NO FIRE WEATHER
CONCERNS.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THERE ARE OF COURSE SOME MINOR DIFFERENCES
IN THE TIMING OF IMPULSES AROUND THE UPPER LOWS. THESE IMPULSES
ARE FAIRLY WEAK AND MAINLY AFFECT THE TIMING OF INCREASING/DECREASING
SHOWER ACTIVITY...WHICH IS FAIRLY EASY TO HANDLE. FORECAST
CONFIDENCE IS A LITTLE HIGHER THAN NORMAL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A SUBTLE EASTERLY WAVE ALOFT IS SPREADING MOISTURE AND CLOUDS
OVER MOST OF MAINLAND SOUTHCENTRAL THIS EVENING. CONVECTIVE RAIN
SHOWERS ARE BREAKING OUT ACROSS THE SUSITNA VALLEY SOUTHWARD TO
THE KENAI PENINSULA. STEADIER AND MORE NUMEROUS RAIN AND SNOW
SHOWERS ARE IMPACTING THE COPPER BASIN AND THOMPSON PASS...WITH
LIGHT SNOW ACCUMULATION POSSIBLE THROUGH THE PASSES AND THE
WESTERN COPPER BASIN THROUGH TONIGHT. AN OFFSHORE PRESSURE
GRADIENT WILL DEVELOP ON TUESDAY...WITH DIMINISHING CLOUD COVER
AND SHOWERS. GUSTY GAP WINDS WILL ALSO DEVELOP ACROSS INLAND
COASTAL LOCATIONS. A WEAK LOW WILL TRACK OVER SOUTHCENTRAL
WEDNESDAY...WITH MORE CLOUDS AND SHOWERS REDEVELOPING OVER THE
MAINLAND. SOUTHEAST WINDS WILL BECOME GUSTY IN THE AFTERNOON...
ESPECIALLY ALONG TURNAGAIN ARM AND SOUTH AND WEST ANCHORAGE.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SOUTHWEST ALASKA IS UNDER A LARGE AREA OF MOSTLY CLEAR SKIES THIS
AFTERNOON WITH A FEW CLOUDS SNEAKING IN FROM THE EAST AS WELL AS
CUMULUS DEVELOPMENT OVER HIGHER ELEVATIONS. THE BIG QUESTION FOR
THIS EVENING IS WHETHER THERE WILL BE ENOUGH INSTABILITY TO
REALLY KICK OFF SHOWERS...AND EVEN THUNDERSTORMS IN THE KUSKOKWIM
VALLEY. THIS IS ONE OF THOSE CASES WHERE THE LINE BETWEEN MOSTLY
CLEAR SKIES AND HAVING QUITE A FEW SHOWERS AND EVEN THUNDERSTORMS
MAY BE QUITE THIN. WHILE SATELLITE IMAGERY SHOWS NOT MUCH IN THE
WAY OF CONVECTIVE BUILD UP SO FAR THEY COULD DEVELOP QUICKLY IF
THE CAPPING INVERSION BREAKS. MEANWHILE...STRATUS LURKING JUST
OFF THE COAST OF BRISTOL BAY WILL LIKELY COME ON SHORE AS THE
TEMPERATURES COOL OFF LATER THIS EVENING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE FIRST LOW IN THE BERING SEA LOCATED WEST OF THE PRIBILOF
ISLANDS IS ELONGATING AND WEAKENING AS IT PUSHES UP AGAINST THE
RIDGE OVER SOUTHWEST ALASKA. THE SECOND LOW TO THE WEST OF IT IS
TAPPING INTO JET SUPPORT AND IS STRENGTHENING IN THE WESTERN
ALEUTIANS. THIS WILL KEEP PRECIPITATION OVER THE BERING SEA AND
SOME GALES SOUTH OF THE ALEUTIANS THE NEXT FEW DAYS.

&&

.LONG TERM FORECAST (DAY 3 THROUGH 7)...
THE STRONG ZONAL JET STREAM OVER THE ALEUTIAN CHAIN CONTINUES TO
TRACK EASTWARD HEADING INTO THE WEEKEND. THERE WILL BE A BROAD
AREA OF LOW PRESSURE IN BERING SEA THAT WILL WEAKEN INTO A TROUGH
THROUGH FRIDAY. BY SATURDAY A NORTH PACIFIC LOW WILL TRACK INTO
THE WESTERN GULF WHILE ANOTHER LOW MOVES OUT OF ASIA AND INTO THE
BERING SEA.

THE GULF WILL HAVE SOUTH TO SOUTHWESTERLY FLOW WITH WEAK DISTURBANCES
MOVING INTO THE AREA THROUGH FRIDAY. THESE SYNOPTIC FEATURES WILL
BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG THE COASTAL AREAS
FOR THE NEXT SEVERAL DAYS. BY THURSDAY AN UPPER LEVEL RIDGE BUILDS
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED AND BE
POSITIONED OVER THE SOUTHCENTRAL REGION EXTENDING INTO MATSU VALLEY
FRIDAY THROUGH THE WEEKEND. THIS SYNOPTIC FEATURE WILL BRING WARMER
TEMPERATURES AND DRIER CONDITIONS TO THE SOUTHCENTRAL REGION. THERE
WILL BE A THERMAL TROUGH SETTING UP OVER THE WEEKEND...WHICH WILL
INCREASE THE CHANCES FOR AFTERNOON TO EVENING SHOWERY ACTIVITY FOR
THE INLAND AREAS. THE MODELS WERE IN BETTER AGREEMENT WITH THE
TIMING AND PLACEMENT OF THE DIFFERENT SYNOPTIC FEATURES...WITH WPC
USING A BLEND OF THE ENSEMBLE MEANS THROUGH THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 174 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...JA
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...EZ
LONG TERM...PD





000
FXAK68 PAFC 280028
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
428 PM AKDT MON APR 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE GULF OF ALASKA. THERE IS A
DISSIPATING LOW OVER THE CENTRAL BERING SEA WITH A WEAK FRONT
STRETCHING EASTWARD ACROSS THE PRIBILOFS AND THEN SOUTHEAST TO
THE WESTERN ALASKA PENINSULA. THERE IS A STRENGTHENING LOW MOVING
INTO THE WESTERN ALEUTIANS FROM THE WEST. STRONG WESTERLY FLOW
ALOFT IS PUSHING ACROSS THE NORTH PACIFIC TO THE SOUTH OF THESE
LOWS. WEAK CYCLONIC FLOW EXISTS TO THE NORTH...COVERING MOST OF
SOUTHERN ALASKA AND THE BERING SEA. A WEAK RIDGE IS OVER THE
BERING STRAIT AND NORTHERN MAINLAND ALASKA. AT THE SURFACE THE
FLOW IS FAIRLY WEAK OVER LAND...WITH A BIT OF A THERMAL TROUGH
OVER CENTRAL ALASKA. HUMIDITIES IN SOUTH CENTRAL HAVE INCREASED
CONSIDERABLY TODAY AND AS A RESULT THERE ARE NO FIRE WEATHER
CONCERNS.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THERE ARE OF COURSE SOME MINOR DIFFERENCES
IN THE TIMING OF IMPULSES AROUND THE UPPER LOWS. THESE IMPULSES
ARE FAIRLY WEAK AND MAINLY AFFECT THE TIMING OF INCREASING/DECREASING
SHOWER ACTIVITY...WHICH IS FAIRLY EASY TO HANDLE. FORECAST
CONFIDENCE IS A LITTLE HIGHER THAN NORMAL.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A SUBTLE EASTERLY WAVE ALOFT IS SPREADING MOISTURE AND CLOUDS
OVER MOST OF MAINLAND SOUTHCENTRAL THIS EVENING. CONVECTIVE RAIN
SHOWERS ARE BREAKING OUT ACROSS THE SUSITNA VALLEY SOUTHWARD TO
THE KENAI PENINSULA. STEADIER AND MORE NUMEROUS RAIN AND SNOW
SHOWERS ARE IMPACTING THE COPPER BASIN AND THOMPSON PASS...WITH
LIGHT SNOW ACCUMULATION POSSIBLE THROUGH THE PASSES AND THE
WESTERN COPPER BASIN THROUGH TONIGHT. AN OFFSHORE PRESSURE
GRADIENT WILL DEVELOP ON TUESDAY...WITH DIMINISHING CLOUD COVER
AND SHOWERS. GUSTY GAP WINDS WILL ALSO DEVELOP ACROSS INLAND
COASTAL LOCATIONS. A WEAK LOW WILL TRACK OVER SOUTHCENTRAL
WEDNESDAY...WITH MORE CLOUDS AND SHOWERS REDEVELOPING OVER THE
MAINLAND. SOUTHEAST WINDS WILL BECOME GUSTY IN THE AFTERNOON...
ESPECIALLY ALONG TURNAGAIN ARM AND SOUTH AND WEST ANCHORAGE.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SOUTHWEST ALASKA IS UNDER A LARGE AREA OF MOSTLY CLEAR SKIES THIS
AFTERNOON WITH A FEW CLOUDS SNEAKING IN FROM THE EAST AS WELL AS
CUMULUS DEVELOPMENT OVER HIGHER ELEVATIONS. THE BIG QUESTION FOR
THIS EVENING IS WHETHER THERE WILL BE ENOUGH INSTABILITY TO
REALLY KICK OFF SHOWERS...AND EVEN THUNDERSTORMS IN THE KUSKOKWIM
VALLEY. THIS IS ONE OF THOSE CASES WHERE THE LINE BETWEEN MOSTLY
CLEAR SKIES AND HAVING QUITE A FEW SHOWERS AND EVEN THUNDERSTORMS
MAY BE QUITE THIN. WHILE SATELLITE IMAGERY SHOWS NOT MUCH IN THE
WAY OF CONVECTIVE BUILD UP SO FAR THEY COULD DEVELOP QUICKLY IF
THE CAPPING INVERSION BREAKS. MEANWHILE...STRATUS LURKING JUST
OFF THE COAST OF BRISTOL BAY WILL LIKELY COME ON SHORE AS THE
TEMPERATURES COOL OFF LATER THIS EVENING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE FIRST LOW IN THE BERING SEA LOCATED WEST OF THE PRIBILOF
ISLANDS IS ELONGATING AND WEAKENING AS IT PUSHES UP AGAINST THE
RIDGE OVER SOUTHWEST ALASKA. THE SECOND LOW TO THE WEST OF IT IS
TAPPING INTO JET SUPPORT AND IS STRENGTHENING IN THE WESTERN
ALEUTIANS. THIS WILL KEEP PRECIPITATION OVER THE BERING SEA AND
SOME GALES SOUTH OF THE ALEUTIANS THE NEXT FEW DAYS.

&&

.LONG TERM FORECAST (DAY 3 THROUGH 7)...
THE STRONG ZONAL JET STREAM OVER THE ALEUTIAN CHAIN CONTINUES TO
TRACK EASTWARD HEADING INTO THE WEEKEND. THERE WILL BE A BROAD
AREA OF LOW PRESSURE IN BERING SEA THAT WILL WEAKEN INTO A TROUGH
THROUGH FRIDAY. BY SATURDAY A NORTH PACIFIC LOW WILL TRACK INTO
THE WESTERN GULF WHILE ANOTHER LOW MOVES OUT OF ASIA AND INTO THE
BERING SEA.

THE GULF WILL HAVE SOUTH TO SOUTHWESTERLY FLOW WITH WEAK DISTURBANCES
MOVING INTO THE AREA THROUGH FRIDAY. THESE SYNOPTIC FEATURES WILL
BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG THE COASTAL AREAS
FOR THE NEXT SEVERAL DAYS. BY THURSDAY AN UPPER LEVEL RIDGE BUILDS
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED AND BE
POSITIONED OVER THE SOUTHCENTRAL REGION EXTENDING INTO MATSU VALLEY
FRIDAY THROUGH THE WEEKEND. THIS SYNOPTIC FEATURE WILL BRING WARMER
TEMPERATURES AND DRIER CONDITIONS TO THE SOUTHCENTRAL REGION. THERE
WILL BE A THERMAL TROUGH SETTING UP OVER THE WEEKEND...WHICH WILL
INCREASE THE CHANCES FOR AFTERNOON TO EVENING SHOWERY ACTIVITY FOR
THE INLAND AREAS. THE MODELS WERE IN BETTER AGREEMENT WITH THE
TIMING AND PLACEMENT OF THE DIFFERENT SYNOPTIC FEATURES...WITH WPC
USING A BLEND OF THE ENSEMBLE MEANS THROUGH THE WEEKEND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 174 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...BL
SOUTHCENTRAL ALASKA...JA
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...EZ
LONG TERM...PD




000
FXAK68 PAFC 271301
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
501 AM AKDT MON APR 27 2015

.ANALYSIS AND UPPER LEVELS...
A SOMEWHAT CHAOTIC PATTERN IS BEGINNING TO EMERGE ALOFT. THE UPPER
LEVEL JET IS IN A CONVERGENT SPLIT FLOW JUST SOUTH OF THE
ALEUTIANS AROUND 140 KTS BEFORE TURNING TO THE SOUTH AROUND THE
GULF/NORTHEAST PACIFIC STORM SYSTEM. THE FEATURES ON THE POLEWARD
SIDE OF THE JET ARE NOW IN A WEAKENING AN MEANDERING STATE
WITHOUT THE MEAN FLOW TO GUIDE THEM. THE BIGGEST PLAYER IS THE
UPPER LOW TAKING UP RESIDENCE IN THE GULF. THE FRONT AND SURFACE
SYSTEM ASSOCIATED WITH THE UPPER LOW CONTINUES TO WEAKEN...THE
MAIN ACTIVITY WITH THIS SYSTEM WILL BE PIECES OF ENERGY COMING
AROUND THE TROUGH THE CURRENTLY STILL HAVE JET SUPPORT TOWARD THE
PANHANDLE. THE OTHER CYCLONIC CIRCULATION IS SPINNING OVER THE
BERING SEA ALONG WITH A FRONT STRETCHING OUT FROM THE PRIBILOF
ISLANDS THROUGH THE END OF THE ALASKA PENINSULA. SKIES ARE MOSTLY
CLEAR OVER THE SOUTHWEST MAINLAND WHILE EASTERLY FLOW IS BRINGING
PLENTY OF MIDDLE AND HIGH CLOUDS OVER THE SOUTHCENTRAL. WINDS
AROUND THE AREA ARE GENERALLY LIGHT WHILE TEMPERATURES ARE
HOVERING SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.

&&

.MODEL DISCUSSION...
GUIDANCE IS BEGINNING TO HANDLE THE COMPLEXITIES OF THE UPCOMING
PATTERN A LITTLE BIT BETTER THAN PREVIOUS DAYS. SYNOPTICALLY...THE
MAIN DIFFERENCES BETWEEN SOLUTIONS ARE HOW A SHORTWAVE TROUGH
COMING OFF THE EAST ASIAN JET INTERACTS FIRST WITH THE BERING SEA
SYSTEM AND THEN WITH THE GULF SYSTEM. ON SHORTER TIME AND SMALLER
SCALES...THE MAIN DIFFERENCES ARE PRECIPITATION CHANCES ACROSS THE
MAINLAND WITH ANY EASTERLY WAVE COMING AROUND THE UPPER LOW.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (TODAY THROUGH TUESDAY)...

EASTERLY DISTURBANCES MOVING FROM THE GULF COAST INLAND WILL
SLOWLY CONTINUE TO MOISTEN THE ATMOSPHERE AND BRING THE NUMEROUS
SHOWERS TO COASTAL LOCATIONS AND ISOLATED TO SCATTERED SHOWERS ON
THE LEE SIDE SLOPES (ANCHORAGE AND THE MAT VALLEY). INITIAL DRY
AIR WILL BE VERY TOUGH TO OVERCOME AT FIRST BUT AS THE DAY
PROGRESSES CLOUD BASES WILL GRADUALLY LOWER. MORE WIDESPREAD RAIN
AND SNOW IS EXPECTED TO DEVELOP ESPECIALLY ACROSS THE EASTERN COPPER
RIVER BASIN AS A WEAK EASTERLY SHORTWAVE MOVES IN AND TAKES
ADVANTAGE OF SOME OF THE EXISTING INSTABILITY OF THE AIRMASS. THE
MOISTURE WITH THIS WAVE WILL HAVE A HARD TIME GETTING OVER THE
CHUGACH RANGE BY TUESDAY...SO ONLY ISOLATED SHOWERS ARE EXPECTED
AT THIS TIME. HOWEVER...UP-INLET SOUTHWEST FLOW DEVELOPING TONIGHT
OVER THE BARREN ISLANDS AND KAMISHAK BAY REGIONS WILL PUSH A
STRATUS DECK ALL THE WAY TO ANCHORAGE FOR TUESDAY...RESULTING IN
CLOUDY AND COOL CONDITIONS LIKELY UNTIL EARLY EVENING.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY THROUGH TUESDAY)...

THE OVERALL DRY PATTERN IS EXPECTED TO CONTINUE THROUGH THE BEGINNING
OF THE WEEK WITH AFTERNOON HIGH TEMPERATURES IN THE 50S AND RELATIVE
HUMIDITY VALUES DROPPING INTO THE 20 PERCENT RANGE. IT IS
BEGINNING TO LOOK MORE FAVORABLE FOR SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP WEST OF THE ALASKA RANGE THIS
AFTERNOON AND EVENING AS A SHORTWAVE PUSHES WESTWARD ACROSS THE
ALASKA RANGE. THE BIG QUESTION FOR THUNDERSTORM DEVELOPMENT WILL
BE HOW MUCH MOISTURE IS AVAILABLE AS A VERY DRY SURFACE LAYER IS
ANTICIPATED. THIS WOULD LIKELY EVAPORATE MUCH OF THE RAINFALL
PRIOR TO IT REACHING THE SURFACE...POSSIBLY LEADING TO A DRY
THUNDERSTORM OR TWO. SCATTERED RAIN SHOWERS WILL BE SEEN AGAIN ON
TUESDAY BUT CONDITIONS APPEAR LESS FAVORABLE FOR ANY THUNDERSTORM
DEVELOPMENT WITH LITTLE TO NO VERTICAL LIFT PRESENT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND TUESDAY)...

AN AREA OF LOW PRESSURE OVER THE WESTERN ALEUTIANS WILL REMAIN
NEARLY STATIONARY DURING THE DAY TODAY WHILE PUSHING A FRONT
ACROSS THE PRIBILOF ISLANDS AND DUTCH HARBOR. THIS WILL BRING
ANOTHER SHOT OF RAIN (MAYBE A FEW FLURRIES NEAR ST PAUL) DURING
THE DAY TODAY. SOME AREAS OF FOG HAVE DEVELOPED IN THE STABLE AIR
MASS AHEAD OF THE FRONT BUT WILL LIKELY MIX OUT DURING THE
AFTERNOON HOURS TODAY. A SECOND AREA OF LOW PRESSURE WILL ENTER
THE BERING SEA THIS AFTERNOON AND ABSORB THE WEAKENING LOW OVER
THE WESTERN BERING SEA. THE WILL LEAD TO AN ELONGATED AREA OF LOW
PRESSURE OVER THE BERING SEA...BRINGING WIDESPREAD RAINFALL TO
THE ALEUTIAN ISLANDS THROUGH MIDWEEK.

&&

.LONG TERM FORECAST (WEDNESDAY THROUGH MONDAY)...
THE 130 KNOT ZONAL JET STREAM OVER THE ALEUTIANS WILL CONTINUE TO
TRACK TO THE EAST HEADING INTO THE WEEKEND. THIS WILL BRING
SEVERAL LOWS FROM THE BERING SEA INTO THE LOWER GULF THROUGH
WEDNESDAY. THESE SYSTEMS WILL BE ACCOMPANIED BY SHOWERS IN THE
GULF AND ALONG THE COASTAL AREAS. BY THURSDAY AND UPPER LEVEL
RIDGE WILL BUILD INTO THE WESTERN GULF. THIS RIDGE WILL BECOME
AMPLIFIED WITH A SOUTHEAST TO NORTHWEST PLACEMENT BY SATURDAY.
THIS SYNOPTIC FEATURE WILL BRING WARMER TEMPERATURES AND DRIER
CONDITIONS TO THE SOUTHCENTRAL REGION. THIS WILL INCREASE THE
CHANCES FOR AFTERNOON TO EVENING SHOWERY ACTIVITY FOR THE INLAND
AREAS.

THIS SYSTEM WILL BRING RAIN OUT AHEAD OF THIS SYSTEM AND RAIN
SHOWERS ON THE BACKSIDE OF THE LOW AS IT MOVES ALONG THE CHAIN. BY
WEDNESDAY ANOTHER WEAK LOW FORMS IN THE WESTERN BERING SEA BEFORE
DIMINISHING INTO A TROUGH OVER THE REGION THROUGH FRIDAY. THEN
ANOTHER NORTH PACIFIC APPROACHES THE WESTERN ALEUTIANS BY
SATURDAY. THIS WILL CONTINUE TO BRING WARMER TEMPERATURES AND RAIN
SHOWERS FOR THE BERING SEA AND THE ALEUTIAN CHAIN HEADING INTO THE
WEEKEND. THE MODELS WERE STRUGGLING WITH THE TIMING AND PLACEMENT
OF THESE LOWS AS THEY TRACK THROUGH THE BERING SEA. THIS RESULTED
IN HPC USING A BLEND OF THE ECMWF/GFS ENSEMBLE MEANS THROUGH THE
NEXT SEVERAL DAYS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...PD





000
FXAK68 PAFC 271301
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
501 AM AKDT MON APR 27 2015

.ANALYSIS AND UPPER LEVELS...
A SOMEWHAT CHAOTIC PATTERN IS BEGINNING TO EMERGE ALOFT. THE UPPER
LEVEL JET IS IN A CONVERGENT SPLIT FLOW JUST SOUTH OF THE
ALEUTIANS AROUND 140 KTS BEFORE TURNING TO THE SOUTH AROUND THE
GULF/NORTHEAST PACIFIC STORM SYSTEM. THE FEATURES ON THE POLEWARD
SIDE OF THE JET ARE NOW IN A WEAKENING AN MEANDERING STATE
WITHOUT THE MEAN FLOW TO GUIDE THEM. THE BIGGEST PLAYER IS THE
UPPER LOW TAKING UP RESIDENCE IN THE GULF. THE FRONT AND SURFACE
SYSTEM ASSOCIATED WITH THE UPPER LOW CONTINUES TO WEAKEN...THE
MAIN ACTIVITY WITH THIS SYSTEM WILL BE PIECES OF ENERGY COMING
AROUND THE TROUGH THE CURRENTLY STILL HAVE JET SUPPORT TOWARD THE
PANHANDLE. THE OTHER CYCLONIC CIRCULATION IS SPINNING OVER THE
BERING SEA ALONG WITH A FRONT STRETCHING OUT FROM THE PRIBILOF
ISLANDS THROUGH THE END OF THE ALASKA PENINSULA. SKIES ARE MOSTLY
CLEAR OVER THE SOUTHWEST MAINLAND WHILE EASTERLY FLOW IS BRINGING
PLENTY OF MIDDLE AND HIGH CLOUDS OVER THE SOUTHCENTRAL. WINDS
AROUND THE AREA ARE GENERALLY LIGHT WHILE TEMPERATURES ARE
HOVERING SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.

&&

.MODEL DISCUSSION...
GUIDANCE IS BEGINNING TO HANDLE THE COMPLEXITIES OF THE UPCOMING
PATTERN A LITTLE BIT BETTER THAN PREVIOUS DAYS. SYNOPTICALLY...THE
MAIN DIFFERENCES BETWEEN SOLUTIONS ARE HOW A SHORTWAVE TROUGH
COMING OFF THE EAST ASIAN JET INTERACTS FIRST WITH THE BERING SEA
SYSTEM AND THEN WITH THE GULF SYSTEM. ON SHORTER TIME AND SMALLER
SCALES...THE MAIN DIFFERENCES ARE PRECIPITATION CHANCES ACROSS THE
MAINLAND WITH ANY EASTERLY WAVE COMING AROUND THE UPPER LOW.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (TODAY THROUGH TUESDAY)...

EASTERLY DISTURBANCES MOVING FROM THE GULF COAST INLAND WILL
SLOWLY CONTINUE TO MOISTEN THE ATMOSPHERE AND BRING THE NUMEROUS
SHOWERS TO COASTAL LOCATIONS AND ISOLATED TO SCATTERED SHOWERS ON
THE LEE SIDE SLOPES (ANCHORAGE AND THE MAT VALLEY). INITIAL DRY
AIR WILL BE VERY TOUGH TO OVERCOME AT FIRST BUT AS THE DAY
PROGRESSES CLOUD BASES WILL GRADUALLY LOWER. MORE WIDESPREAD RAIN
AND SNOW IS EXPECTED TO DEVELOP ESPECIALLY ACROSS THE EASTERN COPPER
RIVER BASIN AS A WEAK EASTERLY SHORTWAVE MOVES IN AND TAKES
ADVANTAGE OF SOME OF THE EXISTING INSTABILITY OF THE AIRMASS. THE
MOISTURE WITH THIS WAVE WILL HAVE A HARD TIME GETTING OVER THE
CHUGACH RANGE BY TUESDAY...SO ONLY ISOLATED SHOWERS ARE EXPECTED
AT THIS TIME. HOWEVER...UP-INLET SOUTHWEST FLOW DEVELOPING TONIGHT
OVER THE BARREN ISLANDS AND KAMISHAK BAY REGIONS WILL PUSH A
STRATUS DECK ALL THE WAY TO ANCHORAGE FOR TUESDAY...RESULTING IN
CLOUDY AND COOL CONDITIONS LIKELY UNTIL EARLY EVENING.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY THROUGH TUESDAY)...

THE OVERALL DRY PATTERN IS EXPECTED TO CONTINUE THROUGH THE BEGINNING
OF THE WEEK WITH AFTERNOON HIGH TEMPERATURES IN THE 50S AND RELATIVE
HUMIDITY VALUES DROPPING INTO THE 20 PERCENT RANGE. IT IS
BEGINNING TO LOOK MORE FAVORABLE FOR SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP WEST OF THE ALASKA RANGE THIS
AFTERNOON AND EVENING AS A SHORTWAVE PUSHES WESTWARD ACROSS THE
ALASKA RANGE. THE BIG QUESTION FOR THUNDERSTORM DEVELOPMENT WILL
BE HOW MUCH MOISTURE IS AVAILABLE AS A VERY DRY SURFACE LAYER IS
ANTICIPATED. THIS WOULD LIKELY EVAPORATE MUCH OF THE RAINFALL
PRIOR TO IT REACHING THE SURFACE...POSSIBLY LEADING TO A DRY
THUNDERSTORM OR TWO. SCATTERED RAIN SHOWERS WILL BE SEEN AGAIN ON
TUESDAY BUT CONDITIONS APPEAR LESS FAVORABLE FOR ANY THUNDERSTORM
DEVELOPMENT WITH LITTLE TO NO VERTICAL LIFT PRESENT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND TUESDAY)...

AN AREA OF LOW PRESSURE OVER THE WESTERN ALEUTIANS WILL REMAIN
NEARLY STATIONARY DURING THE DAY TODAY WHILE PUSHING A FRONT
ACROSS THE PRIBILOF ISLANDS AND DUTCH HARBOR. THIS WILL BRING
ANOTHER SHOT OF RAIN (MAYBE A FEW FLURRIES NEAR ST PAUL) DURING
THE DAY TODAY. SOME AREAS OF FOG HAVE DEVELOPED IN THE STABLE AIR
MASS AHEAD OF THE FRONT BUT WILL LIKELY MIX OUT DURING THE
AFTERNOON HOURS TODAY. A SECOND AREA OF LOW PRESSURE WILL ENTER
THE BERING SEA THIS AFTERNOON AND ABSORB THE WEAKENING LOW OVER
THE WESTERN BERING SEA. THE WILL LEAD TO AN ELONGATED AREA OF LOW
PRESSURE OVER THE BERING SEA...BRINGING WIDESPREAD RAINFALL TO
THE ALEUTIAN ISLANDS THROUGH MIDWEEK.

&&

.LONG TERM FORECAST (WEDNESDAY THROUGH MONDAY)...
THE 130 KNOT ZONAL JET STREAM OVER THE ALEUTIANS WILL CONTINUE TO
TRACK TO THE EAST HEADING INTO THE WEEKEND. THIS WILL BRING
SEVERAL LOWS FROM THE BERING SEA INTO THE LOWER GULF THROUGH
WEDNESDAY. THESE SYSTEMS WILL BE ACCOMPANIED BY SHOWERS IN THE
GULF AND ALONG THE COASTAL AREAS. BY THURSDAY AND UPPER LEVEL
RIDGE WILL BUILD INTO THE WESTERN GULF. THIS RIDGE WILL BECOME
AMPLIFIED WITH A SOUTHEAST TO NORTHWEST PLACEMENT BY SATURDAY.
THIS SYNOPTIC FEATURE WILL BRING WARMER TEMPERATURES AND DRIER
CONDITIONS TO THE SOUTHCENTRAL REGION. THIS WILL INCREASE THE
CHANCES FOR AFTERNOON TO EVENING SHOWERY ACTIVITY FOR THE INLAND
AREAS.

THIS SYSTEM WILL BRING RAIN OUT AHEAD OF THIS SYSTEM AND RAIN
SHOWERS ON THE BACKSIDE OF THE LOW AS IT MOVES ALONG THE CHAIN. BY
WEDNESDAY ANOTHER WEAK LOW FORMS IN THE WESTERN BERING SEA BEFORE
DIMINISHING INTO A TROUGH OVER THE REGION THROUGH FRIDAY. THEN
ANOTHER NORTH PACIFIC APPROACHES THE WESTERN ALEUTIANS BY
SATURDAY. THIS WILL CONTINUE TO BRING WARMER TEMPERATURES AND RAIN
SHOWERS FOR THE BERING SEA AND THE ALEUTIAN CHAIN HEADING INTO THE
WEEKEND. THE MODELS WERE STRUGGLING WITH THE TIMING AND PLACEMENT
OF THESE LOWS AS THEY TRACK THROUGH THE BERING SEA. THIS RESULTED
IN HPC USING A BLEND OF THE ECMWF/GFS ENSEMBLE MEANS THROUGH THE
NEXT SEVERAL DAYS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 176 177.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...PD




000
FXAK68 PAFC 270024
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
424 PM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN WEATHER FEATURE OVER THE EASTERN HALF OF SOUTHERN ALASKA
IS THE LOW IN THE GULF AND THE FRONT ASSOCIATED WITH IT. SOUTHWEST
MAINLAND ALASKA IS UNDER HIGH PRESSURE WITH ANOTHER LOW IN THE
WESTERN BERING SEA THAT HAS A FRONT PUSHING EASTWARD TOWARD THE
PRIBILOF ISLANDS AND AND ACROSS THE ALEUTIANS. THE JET STREAM IS
RUNNING WEST TO EAST OVER THE ALEUTIANS AND THEN DIPPING SOUTH
AROUND THE LOW IN THE GULF BEFORE HEADING BACK TO THE NORTHEAST
OVER PARTS OF THE PANHANDLE.

&&

.MODEL DISCUSSION...
MODELS ARE HANDLING THE SYNOPTIC PATTERN VERY WELL AND ARE
ESPECIALLY GOOD IN THE GULF OF ALASKA REGION. ALL THE MODELS STILL
DISPLAY THE LOW IN THE BERING SEA GETTING ABSORBED BY A STRONGER
ONE TO THE WEST TOMORROW. THE DEVELOPMENT AND MOVEMENT OF THIS
SECOND LOW AFTER IT ABSORBS THE FIRST ONE IS THE AREA WHERE THE
NAM IS STRUGGLING MORE THAN THE OTHER MODELS. THE GFS ECMWF AND
GEM ALL SHOW THIS LOW ELONGATING WITH THE MAIN LOW NEAR DUTCH
HARBOR ON TUESDAY...WITH A TROUGH AND POSSIBLE SECONDARY LOW
TRAILING 500 TO 600 MILES NORTHWEST OF THE MAIN LOW. THE NAM DOES
NOT SEEM TO RECOGNIZE THIS STRUCTURE WHICH IS LIKELY TO OCCUR AND
IS SEEKING A MEAN POSITION BETWEEN THE LOWS. THEREFORE THE NAM WAS
NOT USED IN THIS REGION WITH THE GFS BEING THE PREFERRED SOLUTION.
ANOTHER FEATURE OF INTEREST IS AN EASTERLY WAVE DEVELOPING OVER
THE YUKON ALONG THE FRONT. THE NAM REMAINS MUCH MORE AGGRESSIVE
WITH THIS WAVE BRINGING PRECIPITATION ALL THE WAY TO THE ANCHORAGE
AREA AND SUSITNA VALLEY MONDAY. THE GFS SHOWS THIS FEATURE BUT IS
NOT TREATING IT AS STRONGLY. THE GFS WAS PREFERRED IN THIS AREA AS
WELL WITH THE SHORT WAVE MOVING INTO THE AREA BUT NOT BRINGING
MUCH PRECIPITATION EXCEPT FOR A FEW RAIN SHOWERS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
MUCH OF THE COOK INLET REGION IS ON THE PERIPHERY OF THICKER
CLOUD COVER TO THE SOUTH AND EAST. THESE CLOUDS ARE ASSOCIATED
WITH THE LOW SPINNING WELL SOUTH IN THE GULF. THE WARMEST LOW-
LEVEL AIRMASS OF THE SPRING SO FAR HAS SURGED IN FROM CANADA AHEAD
OF THE WEAK FRONT ALONG THE GULF COAST. DESPITE THE HIGH CLOUDINESS
AND FILTERED SUNSHINE IN UPPER COOK INLET THE TEMPERATURES FOR
MANY AREAS HAVE REACHED THE WARMEST OF THE SEASON SO FAR WITH
MULTIPLE READINGS AROUND 60 FROM EAST ANCHORAGE UP TO THE MAT-SU
VALLEY. THE AIRMASS REMAINS VERY DRY...THOUGH THE GUSTY NORTHEAST
WINDS EXPECTED THIS MORNING HAVE FAILED TO DEVELOP. AS A RESULT...ALL
FIRE WEATHER (RED FLAG) WARNINGS HAVE BEEN CANCELLED.

STEADIER PERIODS OF RAIN REMAIN JUST OFFSHORE MOST OF THE COASTAL
AREAS AT THIS TIME...BUT AS MID- AND UPPER- LEVEL EASTERLY FLOW
CONTINUES ACROSS THE AREA TONIGHT THIS PRECIP SHOULD SLOWLY MAKE
PROGRESS ONSHORE. INCREASED SHOWER ACTIVITY IS ALSO EXPECTED
OVERNIGHT ACROSS THE EASTERN COPPER RIVER BASIN AS A WEAK EASTERLY
SHORTWAVE MOVES IN AND TAKES ADVANTAGE OF SOME OF THE EXISTING
INSTABILITY OF THE AIRMASS. MODEL GUIDANCE IS GENERALLY TRYING TO
SPREAD THIS SHOWER ACTIVITY ALL THE WAY TO THE MAT-SU AND ANCHORAGE
AREAS BY TOMORROW AFTERNOON...THOUGH THE CHALLENGE WITH THIS BEING
REALIZED IS GOING TO BE THE VERY DRY AIRMASS CURRENTLY IN PLACE.
CURRENT THINKING IS THAT THE FORCING WILL NOT BE STRONG ENOUGH TO
BE A BIG/WIDESPREAD RAINMAKER...THUS WILL HEDGE TO THE LOWER/DRIER
END OF THE GUIDANCE ENVELOPE WITH GENERALLY ISOLATED TO SCATTERED
SHOWER ACTIVITY ACROSS THE REGION THROUGH TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TONIGHT THROUGH)...
NORTHERLY FLOW TONIGHT BECOMES LIGHT ON MONDAY AS WEAK RIDGING
SLIDES ACROSS THE SOUTHWEST FROM THE EASTERN BERING. OTHER THAN
PATCHY FOG ALONG THE COAST...RELATIVELY DRY CONDITIONS ARE EXPECTED
THROUGH MID WEEK. A FEW SHOWERS ARE POSSIBLE MONDAY NIGHT AS A
WEAK SHORT WAVE MOVES FROM THE EAST AROUND THE GULF LOW. SHOWERS
WILL BE LIMITED WITH LITTLE MOISTURE AVAILABLE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...
THE STORM SYSTEM ACROSS THE WESTERN BERING WEAKENS BY MONDAY AND
IS FOLLOWED BY A SECOND SYSTEM ON TUESDAY. THIS SYSTEM TAKES A
SOUTHERLY PATH ALONG THE ALEUTIAN CHAIN BRINGING BRIEF GUSTY WINDS
AND PRECIPITATION AS THE SYSTEM TRACKS QUICKLY TO THE ALASKA
PENINSULA BEFORE DIVING SOUTHWARD BY WEDNESDAY MORNING.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE 130 KNOT ZONAL JET STREAM OVER THE ALEUTIANS WILL CONTINUE TO
TRACK TO THE EAST HEADING INTO THE WEEKEND. THIS WILL BRING SEVERAL
LOWS FROM THE BERING SEA INTO THE LOWER GULF THROUGH WEDNESDAY.
THESE SYSTEMS WILL BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG
THE COASTAL AREAS. BY THURSDAY AN UPPER LEVEL RIDGE WILL BUILD
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED WITH A
SOUTHEAST TO NORTHWEST PLACEMENT BY SATURDAY. THIS SYNOPTIC
FEATURE WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS TO
THE SOUTHCENTRAL REGION. THIS WILL INCREASE THE CHANCES FOR
AFTERNOON TO EVENING SHOWERY ACTIVITY FOR THE INLAND AREAS.

THE BERING SEA AND THE ALEUTIAN CHAIN WILL HAVE A LOW OVER THE
WESTERN ALEUTIANS TUESDAY MORNING BEFORE TRACKING TO THE EASTERN
ALEUTIANS BY LATE TUESDAY NIGHT. THIS SYSTEM WILL BRING RAIN OUT
AHEAD OF THIS SYSTEM AND RAIN SHOWERS ON THE BACKSIDE OF THE LOW
AS IT MOVES ALONG THE CHAIN. BY WEDNESDAY ANOTHER WEAK LOW FORMS
IN THE WESTERN BERING SEA BEFORE DIMINISHING INTO A TROUGH OVER
THE REGION THROUGH FRIDAY. THEN ANOTHER NORTH PACIFIC APPROACHES
THE WESTERN ALEUTIANS BY SATURDAY. THIS WILL CONTINUE TO BRING
WARMER TEMPERATURES AND RAIN SHOWERS FOR THE BERING SEA AND THE
ALEUTIAN CHAIN HEADING INTO THE WEEKEND. THE MODELS WERE
STRUGGLING WITH THE TIMING AND PLACEMENT OF THESE LOWS AS THEY
TRACK THROUGH THE BERING SEA. THIS RESULTED IN WPC USING A BLEND
OF THE ECMWF/GFS ENSEMBLE MEANS THROUGH THE NEXT SEVERAL DAYS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 132 177 178.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...PD




000
FXAK68 PAFC 270024
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
424 PM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN WEATHER FEATURE OVER THE EASTERN HALF OF SOUTHERN ALASKA
IS THE LOW IN THE GULF AND THE FRONT ASSOCIATED WITH IT. SOUTHWEST
MAINLAND ALASKA IS UNDER HIGH PRESSURE WITH ANOTHER LOW IN THE
WESTERN BERING SEA THAT HAS A FRONT PUSHING EASTWARD TOWARD THE
PRIBILOF ISLANDS AND AND ACROSS THE ALEUTIANS. THE JET STREAM IS
RUNNING WEST TO EAST OVER THE ALEUTIANS AND THEN DIPPING SOUTH
AROUND THE LOW IN THE GULF BEFORE HEADING BACK TO THE NORTHEAST
OVER PARTS OF THE PANHANDLE.

&&

.MODEL DISCUSSION...
MODELS ARE HANDLING THE SYNOPTIC PATTERN VERY WELL AND ARE
ESPECIALLY GOOD IN THE GULF OF ALASKA REGION. ALL THE MODELS STILL
DISPLAY THE LOW IN THE BERING SEA GETTING ABSORBED BY A STRONGER
ONE TO THE WEST TOMORROW. THE DEVELOPMENT AND MOVEMENT OF THIS
SECOND LOW AFTER IT ABSORBS THE FIRST ONE IS THE AREA WHERE THE
NAM IS STRUGGLING MORE THAN THE OTHER MODELS. THE GFS ECMWF AND
GEM ALL SHOW THIS LOW ELONGATING WITH THE MAIN LOW NEAR DUTCH
HARBOR ON TUESDAY...WITH A TROUGH AND POSSIBLE SECONDARY LOW
TRAILING 500 TO 600 MILES NORTHWEST OF THE MAIN LOW. THE NAM DOES
NOT SEEM TO RECOGNIZE THIS STRUCTURE WHICH IS LIKELY TO OCCUR AND
IS SEEKING A MEAN POSITION BETWEEN THE LOWS. THEREFORE THE NAM WAS
NOT USED IN THIS REGION WITH THE GFS BEING THE PREFERRED SOLUTION.
ANOTHER FEATURE OF INTEREST IS AN EASTERLY WAVE DEVELOPING OVER
THE YUKON ALONG THE FRONT. THE NAM REMAINS MUCH MORE AGGRESSIVE
WITH THIS WAVE BRINGING PRECIPITATION ALL THE WAY TO THE ANCHORAGE
AREA AND SUSITNA VALLEY MONDAY. THE GFS SHOWS THIS FEATURE BUT IS
NOT TREATING IT AS STRONGLY. THE GFS WAS PREFERRED IN THIS AREA AS
WELL WITH THE SHORT WAVE MOVING INTO THE AREA BUT NOT BRINGING
MUCH PRECIPITATION EXCEPT FOR A FEW RAIN SHOWERS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
MUCH OF THE COOK INLET REGION IS ON THE PERIPHERY OF THICKER
CLOUD COVER TO THE SOUTH AND EAST. THESE CLOUDS ARE ASSOCIATED
WITH THE LOW SPINNING WELL SOUTH IN THE GULF. THE WARMEST LOW-
LEVEL AIRMASS OF THE SPRING SO FAR HAS SURGED IN FROM CANADA AHEAD
OF THE WEAK FRONT ALONG THE GULF COAST. DESPITE THE HIGH CLOUDINESS
AND FILTERED SUNSHINE IN UPPER COOK INLET THE TEMPERATURES FOR
MANY AREAS HAVE REACHED THE WARMEST OF THE SEASON SO FAR WITH
MULTIPLE READINGS AROUND 60 FROM EAST ANCHORAGE UP TO THE MAT-SU
VALLEY. THE AIRMASS REMAINS VERY DRY...THOUGH THE GUSTY NORTHEAST
WINDS EXPECTED THIS MORNING HAVE FAILED TO DEVELOP. AS A RESULT...ALL
FIRE WEATHER (RED FLAG) WARNINGS HAVE BEEN CANCELLED.

STEADIER PERIODS OF RAIN REMAIN JUST OFFSHORE MOST OF THE COASTAL
AREAS AT THIS TIME...BUT AS MID- AND UPPER- LEVEL EASTERLY FLOW
CONTINUES ACROSS THE AREA TONIGHT THIS PRECIP SHOULD SLOWLY MAKE
PROGRESS ONSHORE. INCREASED SHOWER ACTIVITY IS ALSO EXPECTED
OVERNIGHT ACROSS THE EASTERN COPPER RIVER BASIN AS A WEAK EASTERLY
SHORTWAVE MOVES IN AND TAKES ADVANTAGE OF SOME OF THE EXISTING
INSTABILITY OF THE AIRMASS. MODEL GUIDANCE IS GENERALLY TRYING TO
SPREAD THIS SHOWER ACTIVITY ALL THE WAY TO THE MAT-SU AND ANCHORAGE
AREAS BY TOMORROW AFTERNOON...THOUGH THE CHALLENGE WITH THIS BEING
REALIZED IS GOING TO BE THE VERY DRY AIRMASS CURRENTLY IN PLACE.
CURRENT THINKING IS THAT THE FORCING WILL NOT BE STRONG ENOUGH TO
BE A BIG/WIDESPREAD RAINMAKER...THUS WILL HEDGE TO THE LOWER/DRIER
END OF THE GUIDANCE ENVELOPE WITH GENERALLY ISOLATED TO SCATTERED
SHOWER ACTIVITY ACROSS THE REGION THROUGH TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TONIGHT THROUGH)...
NORTHERLY FLOW TONIGHT BECOMES LIGHT ON MONDAY AS WEAK RIDGING
SLIDES ACROSS THE SOUTHWEST FROM THE EASTERN BERING. OTHER THAN
PATCHY FOG ALONG THE COAST...RELATIVELY DRY CONDITIONS ARE EXPECTED
THROUGH MID WEEK. A FEW SHOWERS ARE POSSIBLE MONDAY NIGHT AS A
WEAK SHORT WAVE MOVES FROM THE EAST AROUND THE GULF LOW. SHOWERS
WILL BE LIMITED WITH LITTLE MOISTURE AVAILABLE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...
THE STORM SYSTEM ACROSS THE WESTERN BERING WEAKENS BY MONDAY AND
IS FOLLOWED BY A SECOND SYSTEM ON TUESDAY. THIS SYSTEM TAKES A
SOUTHERLY PATH ALONG THE ALEUTIAN CHAIN BRINGING BRIEF GUSTY WINDS
AND PRECIPITATION AS THE SYSTEM TRACKS QUICKLY TO THE ALASKA
PENINSULA BEFORE DIVING SOUTHWARD BY WEDNESDAY MORNING.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE 130 KNOT ZONAL JET STREAM OVER THE ALEUTIANS WILL CONTINUE TO
TRACK TO THE EAST HEADING INTO THE WEEKEND. THIS WILL BRING SEVERAL
LOWS FROM THE BERING SEA INTO THE LOWER GULF THROUGH WEDNESDAY.
THESE SYSTEMS WILL BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG
THE COASTAL AREAS. BY THURSDAY AN UPPER LEVEL RIDGE WILL BUILD
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED WITH A
SOUTHEAST TO NORTHWEST PLACEMENT BY SATURDAY. THIS SYNOPTIC
FEATURE WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS TO
THE SOUTHCENTRAL REGION. THIS WILL INCREASE THE CHANCES FOR
AFTERNOON TO EVENING SHOWERY ACTIVITY FOR THE INLAND AREAS.

THE BERING SEA AND THE ALEUTIAN CHAIN WILL HAVE A LOW OVER THE
WESTERN ALEUTIANS TUESDAY MORNING BEFORE TRACKING TO THE EASTERN
ALEUTIANS BY LATE TUESDAY NIGHT. THIS SYSTEM WILL BRING RAIN OUT
AHEAD OF THIS SYSTEM AND RAIN SHOWERS ON THE BACKSIDE OF THE LOW
AS IT MOVES ALONG THE CHAIN. BY WEDNESDAY ANOTHER WEAK LOW FORMS
IN THE WESTERN BERING SEA BEFORE DIMINISHING INTO A TROUGH OVER
THE REGION THROUGH FRIDAY. THEN ANOTHER NORTH PACIFIC APPROACHES
THE WESTERN ALEUTIANS BY SATURDAY. THIS WILL CONTINUE TO BRING
WARMER TEMPERATURES AND RAIN SHOWERS FOR THE BERING SEA AND THE
ALEUTIAN CHAIN HEADING INTO THE WEEKEND. THE MODELS WERE
STRUGGLING WITH THE TIMING AND PLACEMENT OF THESE LOWS AS THEY
TRACK THROUGH THE BERING SEA. THIS RESULTED IN WPC USING A BLEND
OF THE ECMWF/GFS ENSEMBLE MEANS THROUGH THE NEXT SEVERAL DAYS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 132 177 178.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...PD





000
FXAK68 PAFC 270024
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
424 PM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN WEATHER FEATURE OVER THE EASTERN HALF OF SOUTHERN ALASKA
IS THE LOW IN THE GULF AND THE FRONT ASSOCIATED WITH IT. SOUTHWEST
MAINLAND ALASKA IS UNDER HIGH PRESSURE WITH ANOTHER LOW IN THE
WESTERN BERING SEA THAT HAS A FRONT PUSHING EASTWARD TOWARD THE
PRIBILOF ISLANDS AND AND ACROSS THE ALEUTIANS. THE JET STREAM IS
RUNNING WEST TO EAST OVER THE ALEUTIANS AND THEN DIPPING SOUTH
AROUND THE LOW IN THE GULF BEFORE HEADING BACK TO THE NORTHEAST
OVER PARTS OF THE PANHANDLE.

&&

.MODEL DISCUSSION...
MODELS ARE HANDLING THE SYNOPTIC PATTERN VERY WELL AND ARE
ESPECIALLY GOOD IN THE GULF OF ALASKA REGION. ALL THE MODELS STILL
DISPLAY THE LOW IN THE BERING SEA GETTING ABSORBED BY A STRONGER
ONE TO THE WEST TOMORROW. THE DEVELOPMENT AND MOVEMENT OF THIS
SECOND LOW AFTER IT ABSORBS THE FIRST ONE IS THE AREA WHERE THE
NAM IS STRUGGLING MORE THAN THE OTHER MODELS. THE GFS ECMWF AND
GEM ALL SHOW THIS LOW ELONGATING WITH THE MAIN LOW NEAR DUTCH
HARBOR ON TUESDAY...WITH A TROUGH AND POSSIBLE SECONDARY LOW
TRAILING 500 TO 600 MILES NORTHWEST OF THE MAIN LOW. THE NAM DOES
NOT SEEM TO RECOGNIZE THIS STRUCTURE WHICH IS LIKELY TO OCCUR AND
IS SEEKING A MEAN POSITION BETWEEN THE LOWS. THEREFORE THE NAM WAS
NOT USED IN THIS REGION WITH THE GFS BEING THE PREFERRED SOLUTION.
ANOTHER FEATURE OF INTEREST IS AN EASTERLY WAVE DEVELOPING OVER
THE YUKON ALONG THE FRONT. THE NAM REMAINS MUCH MORE AGGRESSIVE
WITH THIS WAVE BRINGING PRECIPITATION ALL THE WAY TO THE ANCHORAGE
AREA AND SUSITNA VALLEY MONDAY. THE GFS SHOWS THIS FEATURE BUT IS
NOT TREATING IT AS STRONGLY. THE GFS WAS PREFERRED IN THIS AREA AS
WELL WITH THE SHORT WAVE MOVING INTO THE AREA BUT NOT BRINGING
MUCH PRECIPITATION EXCEPT FOR A FEW RAIN SHOWERS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
MUCH OF THE COOK INLET REGION IS ON THE PERIPHERY OF THICKER
CLOUD COVER TO THE SOUTH AND EAST. THESE CLOUDS ARE ASSOCIATED
WITH THE LOW SPINNING WELL SOUTH IN THE GULF. THE WARMEST LOW-
LEVEL AIRMASS OF THE SPRING SO FAR HAS SURGED IN FROM CANADA AHEAD
OF THE WEAK FRONT ALONG THE GULF COAST. DESPITE THE HIGH CLOUDINESS
AND FILTERED SUNSHINE IN UPPER COOK INLET THE TEMPERATURES FOR
MANY AREAS HAVE REACHED THE WARMEST OF THE SEASON SO FAR WITH
MULTIPLE READINGS AROUND 60 FROM EAST ANCHORAGE UP TO THE MAT-SU
VALLEY. THE AIRMASS REMAINS VERY DRY...THOUGH THE GUSTY NORTHEAST
WINDS EXPECTED THIS MORNING HAVE FAILED TO DEVELOP. AS A RESULT...ALL
FIRE WEATHER (RED FLAG) WARNINGS HAVE BEEN CANCELLED.

STEADIER PERIODS OF RAIN REMAIN JUST OFFSHORE MOST OF THE COASTAL
AREAS AT THIS TIME...BUT AS MID- AND UPPER- LEVEL EASTERLY FLOW
CONTINUES ACROSS THE AREA TONIGHT THIS PRECIP SHOULD SLOWLY MAKE
PROGRESS ONSHORE. INCREASED SHOWER ACTIVITY IS ALSO EXPECTED
OVERNIGHT ACROSS THE EASTERN COPPER RIVER BASIN AS A WEAK EASTERLY
SHORTWAVE MOVES IN AND TAKES ADVANTAGE OF SOME OF THE EXISTING
INSTABILITY OF THE AIRMASS. MODEL GUIDANCE IS GENERALLY TRYING TO
SPREAD THIS SHOWER ACTIVITY ALL THE WAY TO THE MAT-SU AND ANCHORAGE
AREAS BY TOMORROW AFTERNOON...THOUGH THE CHALLENGE WITH THIS BEING
REALIZED IS GOING TO BE THE VERY DRY AIRMASS CURRENTLY IN PLACE.
CURRENT THINKING IS THAT THE FORCING WILL NOT BE STRONG ENOUGH TO
BE A BIG/WIDESPREAD RAINMAKER...THUS WILL HEDGE TO THE LOWER/DRIER
END OF THE GUIDANCE ENVELOPE WITH GENERALLY ISOLATED TO SCATTERED
SHOWER ACTIVITY ACROSS THE REGION THROUGH TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TONIGHT THROUGH)...
NORTHERLY FLOW TONIGHT BECOMES LIGHT ON MONDAY AS WEAK RIDGING
SLIDES ACROSS THE SOUTHWEST FROM THE EASTERN BERING. OTHER THAN
PATCHY FOG ALONG THE COAST...RELATIVELY DRY CONDITIONS ARE EXPECTED
THROUGH MID WEEK. A FEW SHOWERS ARE POSSIBLE MONDAY NIGHT AS A
WEAK SHORT WAVE MOVES FROM THE EAST AROUND THE GULF LOW. SHOWERS
WILL BE LIMITED WITH LITTLE MOISTURE AVAILABLE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...
THE STORM SYSTEM ACROSS THE WESTERN BERING WEAKENS BY MONDAY AND
IS FOLLOWED BY A SECOND SYSTEM ON TUESDAY. THIS SYSTEM TAKES A
SOUTHERLY PATH ALONG THE ALEUTIAN CHAIN BRINGING BRIEF GUSTY WINDS
AND PRECIPITATION AS THE SYSTEM TRACKS QUICKLY TO THE ALASKA
PENINSULA BEFORE DIVING SOUTHWARD BY WEDNESDAY MORNING.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE 130 KNOT ZONAL JET STREAM OVER THE ALEUTIANS WILL CONTINUE TO
TRACK TO THE EAST HEADING INTO THE WEEKEND. THIS WILL BRING SEVERAL
LOWS FROM THE BERING SEA INTO THE LOWER GULF THROUGH WEDNESDAY.
THESE SYSTEMS WILL BE ACCOMPANIED BY SHOWERS IN THE GULF AND ALONG
THE COASTAL AREAS. BY THURSDAY AN UPPER LEVEL RIDGE WILL BUILD
INTO THE WESTERN GULF. THIS RIDGE WILL BECOME AMPLIFIED WITH A
SOUTHEAST TO NORTHWEST PLACEMENT BY SATURDAY. THIS SYNOPTIC
FEATURE WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS TO
THE SOUTHCENTRAL REGION. THIS WILL INCREASE THE CHANCES FOR
AFTERNOON TO EVENING SHOWERY ACTIVITY FOR THE INLAND AREAS.

THE BERING SEA AND THE ALEUTIAN CHAIN WILL HAVE A LOW OVER THE
WESTERN ALEUTIANS TUESDAY MORNING BEFORE TRACKING TO THE EASTERN
ALEUTIANS BY LATE TUESDAY NIGHT. THIS SYSTEM WILL BRING RAIN OUT
AHEAD OF THIS SYSTEM AND RAIN SHOWERS ON THE BACKSIDE OF THE LOW
AS IT MOVES ALONG THE CHAIN. BY WEDNESDAY ANOTHER WEAK LOW FORMS
IN THE WESTERN BERING SEA BEFORE DIMINISHING INTO A TROUGH OVER
THE REGION THROUGH FRIDAY. THEN ANOTHER NORTH PACIFIC APPROACHES
THE WESTERN ALEUTIANS BY SATURDAY. THIS WILL CONTINUE TO BRING
WARMER TEMPERATURES AND RAIN SHOWERS FOR THE BERING SEA AND THE
ALEUTIAN CHAIN HEADING INTO THE WEEKEND. THE MODELS WERE
STRUGGLING WITH THE TIMING AND PLACEMENT OF THESE LOWS AS THEY
TRACK THROUGH THE BERING SEA. THIS RESULTED IN WPC USING A BLEND
OF THE ECMWF/GFS ENSEMBLE MEANS THROUGH THE NEXT SEVERAL DAYS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 132 177 178.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AD
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...PD




000
FXAK68 PAFC 261331
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
531 AM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN ACTIVE FEATURE ON WATER VAPOR IMAGERY THIS MORNING
CONTINUES TO BE THE UPPER LEVEL LOW PRESSURE FORMERLY OF THE
BERING SEA...NOW SETTING UP SHOP IN THE SOUTHERN GULF/NORTHEAST
PACIFIC. A STRONG SHORTWAVE TROUGH IS VYING TO BECOME THE NEW
CENTER OF CIRCULATION ALOFT AS THE SURFACE CIRCULATION WITH SAID
SYSTEM ENCOMPASSES MUCH OF THE NORTHEAST PACIFIC/GULF OF ALASKA.
THE VERY WRAPPED UP SYSTEM LOOKS TO BE AT PEAK MATURITY WITH A
GALE FORCE FRONT IN THE CENTRAL GULF. A NARROW RIDGE SITS OVER THE
CENTRAL BERING SEA AHEAD OF A SHORTWAVE TROUGH/FRONT IN THE
WESTERN BERING. THE MAINLAND IS MOSTLY CLOUD FREE AT THE MOMENT
WHILE MOISTURE FROM THE GULF SYSTEM IS ON THE DOORSTEP. WINDS ARE
GENERALLY LIGHT ACROSS MOST OF THE MAINLAND WHILE TEMPERATURES
ARE SLIGHTLY ABOVE NORMAL FOR LATE APRIL.

&&

.MODEL DISCUSSION...
GUIDANCE IS IN GREAT AGREEMENT AS FAR AS POSITION AND STRENGTH OF
THE GULF SYSTEM AND CONTINUE TO BE IN LOCKSTEP FOR THE NEXT COUPLE
DAYS. HOWEVER...THE EXCELLENT AGREEMENT OF THE LAST COUPLE WEEKS
IS ABOUT TO GO DOWN THE TUBES BY MID-WEEK AS MODELS STRUGGLE TO
GRASP THE EVOLUTION OF A SPLIT FLOW PATTERN ALOFT EARLY IN THE
WEEK TO A MORE PROGRESSIVE ZONAL FLOW LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

DRY NORTHERLY WINDS ARE CURRENTLY INCREASING AHEAD OF A WEAK
FRONT THAT WILL MOVE EAST TO WEST ACROSS SOUTHCENTRAL ALASKA
TODAY...REACHING THE COOK INLET AND SOUTHERN SUSITNA VALLEY BY
LATE THIS AFTERNOON OR EARLY THIS EVENING. THE FRONTAL BOUNDARY
WILL END CRITICAL FIRE WEATHER CONDITIONS GRADUALLY FROM EAST TO
WEST STARTING THIS AFTERNOON THROUGH LATE THIS EVENING.

VERY MEAGER HUMIDITY RECOVERIES OVER PARTS OF THE MATANUSKA VALLEY...
ALONG WITH A LATER-THAN-EXPECTED ARRIVAL OF A MARGINALLY SUFFICIENT
WIND OUT OF THE MATANUSKA RIVER VALLEY WILL SIGNAL ONE MORE DAY
OF CRITICAL FIRE WEATHER CONDITIONS IS IN STORE BEFORE THE FRONT
MOVES ACROSS THE AREA THIS AFTERNOON.

FOR THE WESTERN KENAI PENINSULA AND SUSITNA VALLEY...WINDS WILL
INCREASE THROUGH THIS MORNING...BEFORE GRADUALLY DIMINISHING THROUGH
THE AFTERNOON OVER THE WESTERN KENAI PENINSULA. WINDS WILL BE SLOWER
TO DIMINISH OVER NORTHERN AND WESTERN SUSITNA VALLEY AS THE FRONT
WILL STALL OVER THE SOUTHERN SUSITNA VALLEY LATE THIS AFTERNOON THROUGH
TONIGHT.

SYNOPTICALLY...THE STATIONARY LOW PRESSURE SYSTEM OVER THE FAR
SOUTHERN GULF WILL KEEP THE BULK OF THE RAIN AND WIND IMPACTS
CONFINED TO KODIAK ISLAND AND AREAS ALONG THE COAST THROUGH
TONIGHT. A SERIES OF EASTERLY WAVES WITH VARYING STRENGTH WILL
BEGIN TO MOVE ACROSS SOUTHCENTRAL ALASKA BEGINNING TODAY...WITH
THE LEADING SYSTEM BRINGING AN END TO THE RUN OF CRITICAL FIRE
WEATHER DAYS OVER THE UPPER COOK INLET REGION. A STRONGER
DISTURBANCE MOVES OVER THE COPPER RIVER BASIN TONIGHT INTO MONDAY
AND SPREAD RAIN AND SNOW SHOWERS OVER THAT AREA THROUGH
MONDAY...WITH THE CHANCE FOR SHOWERS SPREADING TO THE MAT-SU AND
COOK INLET REGIONS ON MONDAY AS THE WAVE PROGRESSES WESTWARD.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND MONDAY)...

THE OFFSHORE FLOW REGIME HAS BEEN ESTABLISHED ACROSS SOUTHWEST
ALASKA AND IS EXPECTED TO CONTINUE THROUGH MONDAY. WHILE AN
OVERALL DRYING TREND IS EXPECTED AS DRIER AIR IS ADVECTED FROM THE
ALASKAN INTERIOR...A FEW RAIN SHOWERS CANNOT BE RULED OUT OVER THE
COMING DAYS. MONDAY LOOKS TO BE THE MORE FAVORABLE DAY TO SEE SOME
RAIN SHOWERS DEVELOP OVER THE MIDDLE KUSKOKWIM VALLEY AND WESTERN
ALASKA RANGE AS A WEAK SHORTWAVE CROSSES THE ALASKA RANGE FROM THE
EAST. WITH RELATIVE HUMIDITY VALUES TO RANGE FROM THE UPPER TEENS
TO LOWER 30S...IT IS POSSIBLE MUCH OF THE PRECIPITATION WILL
EVAPORATE PRIOR TO REACHING THE SURFACE (VIRGA). THE ENHANCED LIFT
MONDAY AFTERNOON WOULD HELP SOME OF THE RAIN SHOWERS TO OVERCOME A
DEEP DRY LAYER BUT WIDESPREAD SHOWER ACTIVITY IS NOT LIKELY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...

AN AREA OF LOW PRESSURE WELL TREK ACROSS THE WESTERN BERING SEA
TODAY BEFORE STALLING OUT WELL WEST OF THE PRIBILOF ISLANDS ON
MONDAY. A SECOND AREA OF LOW PRESSURE PUSHING OFF THE KOREAN
PENINSULA THIS AFTERNOON WILL QUICKLY CATCH UP TO THE STALLING LOW
IN THE BERING SEA LATE MONDAY AND ABSORB THE DECAYING LOW PRESSURE
SYSTEM. THE FIRST LOW WILL DRIVE A POTENT FRONT ACROSS THE BERING
SEA TODAY WITH RAINFALL EXPECTED FROM SHEMYA TO DUTCH HARBOR
TONIGHT. THE OVERALL PRESSURE FIELD AND 500 MB HEIGHT FIELDS OVER
THE PAST SEVERAL DAYS HAVE BEEN LOWER THAN AVERAGE SO EVEN THOUGH
THESE LOWS WILL BE STRENGTHENING OVER THE BERING SEA...ONLY A VERY
NARROW BAND OF GALE FORCE WINDS IS EXPECTED OVER THE FAR WESTERN
BERING SEA. PRECIPITATION WILL END QUICKLY BEHIND THIS FRONT BUT
ANOTHER ROUND OF RAIN WILL BE OBSERVED WHEN THE SECOND LOW MOVES
INTO THE WESTERN BERING SEA LATE MONDAY.

&&

.LONG TERM FORECAST (MONDAY NIGHT THROUGH SUNDAY)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING THROUGH
THE SOUTHERN BERING AND INTO THE GULF. THERE IS GOOD AGREEMENT
HOWEVER THAT THESE LOWS WILL STAY MAINLY SOUTH OF THE
MAINLAND...WHICH WILL ALLOW FOR GENERALLY OFFSHORE FLOW AND RAIN
CHANCES LIMITED TO CONVECTIVE SHOWERS THROUGH EARLY NEXT WEEK. BY
THE MIDDLE OF NEXT WEEK...MODEL DIFFERENCES DEVELOP WITH THE EXACT
TRACK OF THESE LOWS AND THE OPERATIONAL MODEL RUNS HAVE NOT BEEN
ABLE TO LOCK DOWN EXACT LOW PLACEMENT. THEREFORE A BLEND OF THE
ENSEMBLES WAS USED FOR THEIR POSITIONS. HOWEVER...THE PROGRESSIVE
PATTERN WOULD BE EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND
AREAS ALONG THE NORTH GULF COAST AS THESE LOWS PASS. WITH THE
INSTABILITY OVER THE MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN
ALSO BE EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 177 178.
FIRE WEATHER...RED FLAG WARNING 111 121 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...DK/DEK




000
FXAK68 PAFC 261331
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
531 AM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN ACTIVE FEATURE ON WATER VAPOR IMAGERY THIS MORNING
CONTINUES TO BE THE UPPER LEVEL LOW PRESSURE FORMERLY OF THE
BERING SEA...NOW SETTING UP SHOP IN THE SOUTHERN GULF/NORTHEAST
PACIFIC. A STRONG SHORTWAVE TROUGH IS VYING TO BECOME THE NEW
CENTER OF CIRCULATION ALOFT AS THE SURFACE CIRCULATION WITH SAID
SYSTEM ENCOMPASSES MUCH OF THE NORTHEAST PACIFIC/GULF OF ALASKA.
THE VERY WRAPPED UP SYSTEM LOOKS TO BE AT PEAK MATURITY WITH A
GALE FORCE FRONT IN THE CENTRAL GULF. A NARROW RIDGE SITS OVER THE
CENTRAL BERING SEA AHEAD OF A SHORTWAVE TROUGH/FRONT IN THE
WESTERN BERING. THE MAINLAND IS MOSTLY CLOUD FREE AT THE MOMENT
WHILE MOISTURE FROM THE GULF SYSTEM IS ON THE DOORSTEP. WINDS ARE
GENERALLY LIGHT ACROSS MOST OF THE MAINLAND WHILE TEMPERATURES
ARE SLIGHTLY ABOVE NORMAL FOR LATE APRIL.

&&

.MODEL DISCUSSION...
GUIDANCE IS IN GREAT AGREEMENT AS FAR AS POSITION AND STRENGTH OF
THE GULF SYSTEM AND CONTINUE TO BE IN LOCKSTEP FOR THE NEXT COUPLE
DAYS. HOWEVER...THE EXCELLENT AGREEMENT OF THE LAST COUPLE WEEKS
IS ABOUT TO GO DOWN THE TUBES BY MID-WEEK AS MODELS STRUGGLE TO
GRASP THE EVOLUTION OF A SPLIT FLOW PATTERN ALOFT EARLY IN THE
WEEK TO A MORE PROGRESSIVE ZONAL FLOW LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

DRY NORTHERLY WINDS ARE CURRENTLY INCREASING AHEAD OF A WEAK
FRONT THAT WILL MOVE EAST TO WEST ACROSS SOUTHCENTRAL ALASKA
TODAY...REACHING THE COOK INLET AND SOUTHERN SUSITNA VALLEY BY
LATE THIS AFTERNOON OR EARLY THIS EVENING. THE FRONTAL BOUNDARY
WILL END CRITICAL FIRE WEATHER CONDITIONS GRADUALLY FROM EAST TO
WEST STARTING THIS AFTERNOON THROUGH LATE THIS EVENING.

VERY MEAGER HUMIDITY RECOVERIES OVER PARTS OF THE MATANUSKA VALLEY...
ALONG WITH A LATER-THAN-EXPECTED ARRIVAL OF A MARGINALLY SUFFICIENT
WIND OUT OF THE MATANUSKA RIVER VALLEY WILL SIGNAL ONE MORE DAY
OF CRITICAL FIRE WEATHER CONDITIONS IS IN STORE BEFORE THE FRONT
MOVES ACROSS THE AREA THIS AFTERNOON.

FOR THE WESTERN KENAI PENINSULA AND SUSITNA VALLEY...WINDS WILL
INCREASE THROUGH THIS MORNING...BEFORE GRADUALLY DIMINISHING THROUGH
THE AFTERNOON OVER THE WESTERN KENAI PENINSULA. WINDS WILL BE SLOWER
TO DIMINISH OVER NORTHERN AND WESTERN SUSITNA VALLEY AS THE FRONT
WILL STALL OVER THE SOUTHERN SUSITNA VALLEY LATE THIS AFTERNOON THROUGH
TONIGHT.

SYNOPTICALLY...THE STATIONARY LOW PRESSURE SYSTEM OVER THE FAR
SOUTHERN GULF WILL KEEP THE BULK OF THE RAIN AND WIND IMPACTS
CONFINED TO KODIAK ISLAND AND AREAS ALONG THE COAST THROUGH
TONIGHT. A SERIES OF EASTERLY WAVES WITH VARYING STRENGTH WILL
BEGIN TO MOVE ACROSS SOUTHCENTRAL ALASKA BEGINNING TODAY...WITH
THE LEADING SYSTEM BRINGING AN END TO THE RUN OF CRITICAL FIRE
WEATHER DAYS OVER THE UPPER COOK INLET REGION. A STRONGER
DISTURBANCE MOVES OVER THE COPPER RIVER BASIN TONIGHT INTO MONDAY
AND SPREAD RAIN AND SNOW SHOWERS OVER THAT AREA THROUGH
MONDAY...WITH THE CHANCE FOR SHOWERS SPREADING TO THE MAT-SU AND
COOK INLET REGIONS ON MONDAY AS THE WAVE PROGRESSES WESTWARD.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND MONDAY)...

THE OFFSHORE FLOW REGIME HAS BEEN ESTABLISHED ACROSS SOUTHWEST
ALASKA AND IS EXPECTED TO CONTINUE THROUGH MONDAY. WHILE AN
OVERALL DRYING TREND IS EXPECTED AS DRIER AIR IS ADVECTED FROM THE
ALASKAN INTERIOR...A FEW RAIN SHOWERS CANNOT BE RULED OUT OVER THE
COMING DAYS. MONDAY LOOKS TO BE THE MORE FAVORABLE DAY TO SEE SOME
RAIN SHOWERS DEVELOP OVER THE MIDDLE KUSKOKWIM VALLEY AND WESTERN
ALASKA RANGE AS A WEAK SHORTWAVE CROSSES THE ALASKA RANGE FROM THE
EAST. WITH RELATIVE HUMIDITY VALUES TO RANGE FROM THE UPPER TEENS
TO LOWER 30S...IT IS POSSIBLE MUCH OF THE PRECIPITATION WILL
EVAPORATE PRIOR TO REACHING THE SURFACE (VIRGA). THE ENHANCED LIFT
MONDAY AFTERNOON WOULD HELP SOME OF THE RAIN SHOWERS TO OVERCOME A
DEEP DRY LAYER BUT WIDESPREAD SHOWER ACTIVITY IS NOT LIKELY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...

AN AREA OF LOW PRESSURE WELL TREK ACROSS THE WESTERN BERING SEA
TODAY BEFORE STALLING OUT WELL WEST OF THE PRIBILOF ISLANDS ON
MONDAY. A SECOND AREA OF LOW PRESSURE PUSHING OFF THE KOREAN
PENINSULA THIS AFTERNOON WILL QUICKLY CATCH UP TO THE STALLING LOW
IN THE BERING SEA LATE MONDAY AND ABSORB THE DECAYING LOW PRESSURE
SYSTEM. THE FIRST LOW WILL DRIVE A POTENT FRONT ACROSS THE BERING
SEA TODAY WITH RAINFALL EXPECTED FROM SHEMYA TO DUTCH HARBOR
TONIGHT. THE OVERALL PRESSURE FIELD AND 500 MB HEIGHT FIELDS OVER
THE PAST SEVERAL DAYS HAVE BEEN LOWER THAN AVERAGE SO EVEN THOUGH
THESE LOWS WILL BE STRENGTHENING OVER THE BERING SEA...ONLY A VERY
NARROW BAND OF GALE FORCE WINDS IS EXPECTED OVER THE FAR WESTERN
BERING SEA. PRECIPITATION WILL END QUICKLY BEHIND THIS FRONT BUT
ANOTHER ROUND OF RAIN WILL BE OBSERVED WHEN THE SECOND LOW MOVES
INTO THE WESTERN BERING SEA LATE MONDAY.

&&

.LONG TERM FORECAST (MONDAY NIGHT THROUGH SUNDAY)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING THROUGH
THE SOUTHERN BERING AND INTO THE GULF. THERE IS GOOD AGREEMENT
HOWEVER THAT THESE LOWS WILL STAY MAINLY SOUTH OF THE
MAINLAND...WHICH WILL ALLOW FOR GENERALLY OFFSHORE FLOW AND RAIN
CHANCES LIMITED TO CONVECTIVE SHOWERS THROUGH EARLY NEXT WEEK. BY
THE MIDDLE OF NEXT WEEK...MODEL DIFFERENCES DEVELOP WITH THE EXACT
TRACK OF THESE LOWS AND THE OPERATIONAL MODEL RUNS HAVE NOT BEEN
ABLE TO LOCK DOWN EXACT LOW PLACEMENT. THEREFORE A BLEND OF THE
ENSEMBLES WAS USED FOR THEIR POSITIONS. HOWEVER...THE PROGRESSIVE
PATTERN WOULD BE EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND
AREAS ALONG THE NORTH GULF COAST AS THESE LOWS PASS. WITH THE
INSTABILITY OVER THE MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN
ALSO BE EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 177 178.
FIRE WEATHER...RED FLAG WARNING 111 121 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...DK/DEK





000
FXAK68 PAFC 261331
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
531 AM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN ACTIVE FEATURE ON WATER VAPOR IMAGERY THIS MORNING
CONTINUES TO BE THE UPPER LEVEL LOW PRESSURE FORMERLY OF THE
BERING SEA...NOW SETTING UP SHOP IN THE SOUTHERN GULF/NORTHEAST
PACIFIC. A STRONG SHORTWAVE TROUGH IS VYING TO BECOME THE NEW
CENTER OF CIRCULATION ALOFT AS THE SURFACE CIRCULATION WITH SAID
SYSTEM ENCOMPASSES MUCH OF THE NORTHEAST PACIFIC/GULF OF ALASKA.
THE VERY WRAPPED UP SYSTEM LOOKS TO BE AT PEAK MATURITY WITH A
GALE FORCE FRONT IN THE CENTRAL GULF. A NARROW RIDGE SITS OVER THE
CENTRAL BERING SEA AHEAD OF A SHORTWAVE TROUGH/FRONT IN THE
WESTERN BERING. THE MAINLAND IS MOSTLY CLOUD FREE AT THE MOMENT
WHILE MOISTURE FROM THE GULF SYSTEM IS ON THE DOORSTEP. WINDS ARE
GENERALLY LIGHT ACROSS MOST OF THE MAINLAND WHILE TEMPERATURES
ARE SLIGHTLY ABOVE NORMAL FOR LATE APRIL.

&&

.MODEL DISCUSSION...
GUIDANCE IS IN GREAT AGREEMENT AS FAR AS POSITION AND STRENGTH OF
THE GULF SYSTEM AND CONTINUE TO BE IN LOCKSTEP FOR THE NEXT COUPLE
DAYS. HOWEVER...THE EXCELLENT AGREEMENT OF THE LAST COUPLE WEEKS
IS ABOUT TO GO DOWN THE TUBES BY MID-WEEK AS MODELS STRUGGLE TO
GRASP THE EVOLUTION OF A SPLIT FLOW PATTERN ALOFT EARLY IN THE
WEEK TO A MORE PROGRESSIVE ZONAL FLOW LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

DRY NORTHERLY WINDS ARE CURRENTLY INCREASING AHEAD OF A WEAK
FRONT THAT WILL MOVE EAST TO WEST ACROSS SOUTHCENTRAL ALASKA
TODAY...REACHING THE COOK INLET AND SOUTHERN SUSITNA VALLEY BY
LATE THIS AFTERNOON OR EARLY THIS EVENING. THE FRONTAL BOUNDARY
WILL END CRITICAL FIRE WEATHER CONDITIONS GRADUALLY FROM EAST TO
WEST STARTING THIS AFTERNOON THROUGH LATE THIS EVENING.

VERY MEAGER HUMIDITY RECOVERIES OVER PARTS OF THE MATANUSKA VALLEY...
ALONG WITH A LATER-THAN-EXPECTED ARRIVAL OF A MARGINALLY SUFFICIENT
WIND OUT OF THE MATANUSKA RIVER VALLEY WILL SIGNAL ONE MORE DAY
OF CRITICAL FIRE WEATHER CONDITIONS IS IN STORE BEFORE THE FRONT
MOVES ACROSS THE AREA THIS AFTERNOON.

FOR THE WESTERN KENAI PENINSULA AND SUSITNA VALLEY...WINDS WILL
INCREASE THROUGH THIS MORNING...BEFORE GRADUALLY DIMINISHING THROUGH
THE AFTERNOON OVER THE WESTERN KENAI PENINSULA. WINDS WILL BE SLOWER
TO DIMINISH OVER NORTHERN AND WESTERN SUSITNA VALLEY AS THE FRONT
WILL STALL OVER THE SOUTHERN SUSITNA VALLEY LATE THIS AFTERNOON THROUGH
TONIGHT.

SYNOPTICALLY...THE STATIONARY LOW PRESSURE SYSTEM OVER THE FAR
SOUTHERN GULF WILL KEEP THE BULK OF THE RAIN AND WIND IMPACTS
CONFINED TO KODIAK ISLAND AND AREAS ALONG THE COAST THROUGH
TONIGHT. A SERIES OF EASTERLY WAVES WITH VARYING STRENGTH WILL
BEGIN TO MOVE ACROSS SOUTHCENTRAL ALASKA BEGINNING TODAY...WITH
THE LEADING SYSTEM BRINGING AN END TO THE RUN OF CRITICAL FIRE
WEATHER DAYS OVER THE UPPER COOK INLET REGION. A STRONGER
DISTURBANCE MOVES OVER THE COPPER RIVER BASIN TONIGHT INTO MONDAY
AND SPREAD RAIN AND SNOW SHOWERS OVER THAT AREA THROUGH
MONDAY...WITH THE CHANCE FOR SHOWERS SPREADING TO THE MAT-SU AND
COOK INLET REGIONS ON MONDAY AS THE WAVE PROGRESSES WESTWARD.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND MONDAY)...

THE OFFSHORE FLOW REGIME HAS BEEN ESTABLISHED ACROSS SOUTHWEST
ALASKA AND IS EXPECTED TO CONTINUE THROUGH MONDAY. WHILE AN
OVERALL DRYING TREND IS EXPECTED AS DRIER AIR IS ADVECTED FROM THE
ALASKAN INTERIOR...A FEW RAIN SHOWERS CANNOT BE RULED OUT OVER THE
COMING DAYS. MONDAY LOOKS TO BE THE MORE FAVORABLE DAY TO SEE SOME
RAIN SHOWERS DEVELOP OVER THE MIDDLE KUSKOKWIM VALLEY AND WESTERN
ALASKA RANGE AS A WEAK SHORTWAVE CROSSES THE ALASKA RANGE FROM THE
EAST. WITH RELATIVE HUMIDITY VALUES TO RANGE FROM THE UPPER TEENS
TO LOWER 30S...IT IS POSSIBLE MUCH OF THE PRECIPITATION WILL
EVAPORATE PRIOR TO REACHING THE SURFACE (VIRGA). THE ENHANCED LIFT
MONDAY AFTERNOON WOULD HELP SOME OF THE RAIN SHOWERS TO OVERCOME A
DEEP DRY LAYER BUT WIDESPREAD SHOWER ACTIVITY IS NOT LIKELY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...

AN AREA OF LOW PRESSURE WELL TREK ACROSS THE WESTERN BERING SEA
TODAY BEFORE STALLING OUT WELL WEST OF THE PRIBILOF ISLANDS ON
MONDAY. A SECOND AREA OF LOW PRESSURE PUSHING OFF THE KOREAN
PENINSULA THIS AFTERNOON WILL QUICKLY CATCH UP TO THE STALLING LOW
IN THE BERING SEA LATE MONDAY AND ABSORB THE DECAYING LOW PRESSURE
SYSTEM. THE FIRST LOW WILL DRIVE A POTENT FRONT ACROSS THE BERING
SEA TODAY WITH RAINFALL EXPECTED FROM SHEMYA TO DUTCH HARBOR
TONIGHT. THE OVERALL PRESSURE FIELD AND 500 MB HEIGHT FIELDS OVER
THE PAST SEVERAL DAYS HAVE BEEN LOWER THAN AVERAGE SO EVEN THOUGH
THESE LOWS WILL BE STRENGTHENING OVER THE BERING SEA...ONLY A VERY
NARROW BAND OF GALE FORCE WINDS IS EXPECTED OVER THE FAR WESTERN
BERING SEA. PRECIPITATION WILL END QUICKLY BEHIND THIS FRONT BUT
ANOTHER ROUND OF RAIN WILL BE OBSERVED WHEN THE SECOND LOW MOVES
INTO THE WESTERN BERING SEA LATE MONDAY.

&&

.LONG TERM FORECAST (MONDAY NIGHT THROUGH SUNDAY)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING THROUGH
THE SOUTHERN BERING AND INTO THE GULF. THERE IS GOOD AGREEMENT
HOWEVER THAT THESE LOWS WILL STAY MAINLY SOUTH OF THE
MAINLAND...WHICH WILL ALLOW FOR GENERALLY OFFSHORE FLOW AND RAIN
CHANCES LIMITED TO CONVECTIVE SHOWERS THROUGH EARLY NEXT WEEK. BY
THE MIDDLE OF NEXT WEEK...MODEL DIFFERENCES DEVELOP WITH THE EXACT
TRACK OF THESE LOWS AND THE OPERATIONAL MODEL RUNS HAVE NOT BEEN
ABLE TO LOCK DOWN EXACT LOW PLACEMENT. THEREFORE A BLEND OF THE
ENSEMBLES WAS USED FOR THEIR POSITIONS. HOWEVER...THE PROGRESSIVE
PATTERN WOULD BE EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND
AREAS ALONG THE NORTH GULF COAST AS THESE LOWS PASS. WITH THE
INSTABILITY OVER THE MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN
ALSO BE EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 177 178.
FIRE WEATHER...RED FLAG WARNING 111 121 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...DK/DEK





000
FXAK68 PAFC 261331
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
531 AM AKDT SUN APR 26 2015

.ANALYSIS AND UPPER LEVELS...
THE MAIN ACTIVE FEATURE ON WATER VAPOR IMAGERY THIS MORNING
CONTINUES TO BE THE UPPER LEVEL LOW PRESSURE FORMERLY OF THE
BERING SEA...NOW SETTING UP SHOP IN THE SOUTHERN GULF/NORTHEAST
PACIFIC. A STRONG SHORTWAVE TROUGH IS VYING TO BECOME THE NEW
CENTER OF CIRCULATION ALOFT AS THE SURFACE CIRCULATION WITH SAID
SYSTEM ENCOMPASSES MUCH OF THE NORTHEAST PACIFIC/GULF OF ALASKA.
THE VERY WRAPPED UP SYSTEM LOOKS TO BE AT PEAK MATURITY WITH A
GALE FORCE FRONT IN THE CENTRAL GULF. A NARROW RIDGE SITS OVER THE
CENTRAL BERING SEA AHEAD OF A SHORTWAVE TROUGH/FRONT IN THE
WESTERN BERING. THE MAINLAND IS MOSTLY CLOUD FREE AT THE MOMENT
WHILE MOISTURE FROM THE GULF SYSTEM IS ON THE DOORSTEP. WINDS ARE
GENERALLY LIGHT ACROSS MOST OF THE MAINLAND WHILE TEMPERATURES
ARE SLIGHTLY ABOVE NORMAL FOR LATE APRIL.

&&

.MODEL DISCUSSION...
GUIDANCE IS IN GREAT AGREEMENT AS FAR AS POSITION AND STRENGTH OF
THE GULF SYSTEM AND CONTINUE TO BE IN LOCKSTEP FOR THE NEXT COUPLE
DAYS. HOWEVER...THE EXCELLENT AGREEMENT OF THE LAST COUPLE WEEKS
IS ABOUT TO GO DOWN THE TUBES BY MID-WEEK AS MODELS STRUGGLE TO
GRASP THE EVOLUTION OF A SPLIT FLOW PATTERN ALOFT EARLY IN THE
WEEK TO A MORE PROGRESSIVE ZONAL FLOW LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

DRY NORTHERLY WINDS ARE CURRENTLY INCREASING AHEAD OF A WEAK
FRONT THAT WILL MOVE EAST TO WEST ACROSS SOUTHCENTRAL ALASKA
TODAY...REACHING THE COOK INLET AND SOUTHERN SUSITNA VALLEY BY
LATE THIS AFTERNOON OR EARLY THIS EVENING. THE FRONTAL BOUNDARY
WILL END CRITICAL FIRE WEATHER CONDITIONS GRADUALLY FROM EAST TO
WEST STARTING THIS AFTERNOON THROUGH LATE THIS EVENING.

VERY MEAGER HUMIDITY RECOVERIES OVER PARTS OF THE MATANUSKA VALLEY...
ALONG WITH A LATER-THAN-EXPECTED ARRIVAL OF A MARGINALLY SUFFICIENT
WIND OUT OF THE MATANUSKA RIVER VALLEY WILL SIGNAL ONE MORE DAY
OF CRITICAL FIRE WEATHER CONDITIONS IS IN STORE BEFORE THE FRONT
MOVES ACROSS THE AREA THIS AFTERNOON.

FOR THE WESTERN KENAI PENINSULA AND SUSITNA VALLEY...WINDS WILL
INCREASE THROUGH THIS MORNING...BEFORE GRADUALLY DIMINISHING THROUGH
THE AFTERNOON OVER THE WESTERN KENAI PENINSULA. WINDS WILL BE SLOWER
TO DIMINISH OVER NORTHERN AND WESTERN SUSITNA VALLEY AS THE FRONT
WILL STALL OVER THE SOUTHERN SUSITNA VALLEY LATE THIS AFTERNOON THROUGH
TONIGHT.

SYNOPTICALLY...THE STATIONARY LOW PRESSURE SYSTEM OVER THE FAR
SOUTHERN GULF WILL KEEP THE BULK OF THE RAIN AND WIND IMPACTS
CONFINED TO KODIAK ISLAND AND AREAS ALONG THE COAST THROUGH
TONIGHT. A SERIES OF EASTERLY WAVES WITH VARYING STRENGTH WILL
BEGIN TO MOVE ACROSS SOUTHCENTRAL ALASKA BEGINNING TODAY...WITH
THE LEADING SYSTEM BRINGING AN END TO THE RUN OF CRITICAL FIRE
WEATHER DAYS OVER THE UPPER COOK INLET REGION. A STRONGER
DISTURBANCE MOVES OVER THE COPPER RIVER BASIN TONIGHT INTO MONDAY
AND SPREAD RAIN AND SNOW SHOWERS OVER THAT AREA THROUGH
MONDAY...WITH THE CHANCE FOR SHOWERS SPREADING TO THE MAT-SU AND
COOK INLET REGIONS ON MONDAY AS THE WAVE PROGRESSES WESTWARD.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND MONDAY)...

THE OFFSHORE FLOW REGIME HAS BEEN ESTABLISHED ACROSS SOUTHWEST
ALASKA AND IS EXPECTED TO CONTINUE THROUGH MONDAY. WHILE AN
OVERALL DRYING TREND IS EXPECTED AS DRIER AIR IS ADVECTED FROM THE
ALASKAN INTERIOR...A FEW RAIN SHOWERS CANNOT BE RULED OUT OVER THE
COMING DAYS. MONDAY LOOKS TO BE THE MORE FAVORABLE DAY TO SEE SOME
RAIN SHOWERS DEVELOP OVER THE MIDDLE KUSKOKWIM VALLEY AND WESTERN
ALASKA RANGE AS A WEAK SHORTWAVE CROSSES THE ALASKA RANGE FROM THE
EAST. WITH RELATIVE HUMIDITY VALUES TO RANGE FROM THE UPPER TEENS
TO LOWER 30S...IT IS POSSIBLE MUCH OF THE PRECIPITATION WILL
EVAPORATE PRIOR TO REACHING THE SURFACE (VIRGA). THE ENHANCED LIFT
MONDAY AFTERNOON WOULD HELP SOME OF THE RAIN SHOWERS TO OVERCOME A
DEEP DRY LAYER BUT WIDESPREAD SHOWER ACTIVITY IS NOT LIKELY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND MONDAY)...

AN AREA OF LOW PRESSURE WELL TREK ACROSS THE WESTERN BERING SEA
TODAY BEFORE STALLING OUT WELL WEST OF THE PRIBILOF ISLANDS ON
MONDAY. A SECOND AREA OF LOW PRESSURE PUSHING OFF THE KOREAN
PENINSULA THIS AFTERNOON WILL QUICKLY CATCH UP TO THE STALLING LOW
IN THE BERING SEA LATE MONDAY AND ABSORB THE DECAYING LOW PRESSURE
SYSTEM. THE FIRST LOW WILL DRIVE A POTENT FRONT ACROSS THE BERING
SEA TODAY WITH RAINFALL EXPECTED FROM SHEMYA TO DUTCH HARBOR
TONIGHT. THE OVERALL PRESSURE FIELD AND 500 MB HEIGHT FIELDS OVER
THE PAST SEVERAL DAYS HAVE BEEN LOWER THAN AVERAGE SO EVEN THOUGH
THESE LOWS WILL BE STRENGTHENING OVER THE BERING SEA...ONLY A VERY
NARROW BAND OF GALE FORCE WINDS IS EXPECTED OVER THE FAR WESTERN
BERING SEA. PRECIPITATION WILL END QUICKLY BEHIND THIS FRONT BUT
ANOTHER ROUND OF RAIN WILL BE OBSERVED WHEN THE SECOND LOW MOVES
INTO THE WESTERN BERING SEA LATE MONDAY.

&&

.LONG TERM FORECAST (MONDAY NIGHT THROUGH SUNDAY)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING THROUGH
THE SOUTHERN BERING AND INTO THE GULF. THERE IS GOOD AGREEMENT
HOWEVER THAT THESE LOWS WILL STAY MAINLY SOUTH OF THE
MAINLAND...WHICH WILL ALLOW FOR GENERALLY OFFSHORE FLOW AND RAIN
CHANCES LIMITED TO CONVECTIVE SHOWERS THROUGH EARLY NEXT WEEK. BY
THE MIDDLE OF NEXT WEEK...MODEL DIFFERENCES DEVELOP WITH THE EXACT
TRACK OF THESE LOWS AND THE OPERATIONAL MODEL RUNS HAVE NOT BEEN
ABLE TO LOCK DOWN EXACT LOW PLACEMENT. THEREFORE A BLEND OF THE
ENSEMBLES WAS USED FOR THEIR POSITIONS. HOWEVER...THE PROGRESSIVE
PATTERN WOULD BE EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND
AREAS ALONG THE NORTH GULF COAST AS THESE LOWS PASS. WITH THE
INSTABILITY OVER THE MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN
ALSO BE EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 177 178.
FIRE WEATHER...RED FLAG WARNING 111 121 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...CC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...DK/DEK




000
FXAK68 PAFC 260046 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
446 PM AKDT SAT APR 25 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL LOW IS OVER THE ALASKA PENINSULA THIS AFTERNOON
AS IT MAKES ITS WAY INTO THE GULF BY MONDAY. THIS IS LEAVING AN
UPPER LEVEL RIDGE OVER THE CENTRAL BERING SEA WITH ANOTHER UPPER
LEVEL RIDGE OVER THE YUKON...WHICH IS RAPIDLY DECAYING. THE JET
STREAM IS RUNNING OVER THE TOP OF THE ALEUTIANS AND THEN HEADING
SOUTH OF THE UPPER LEVEL LOW BEFORE TURNING BACK TO THE NORTHEAST
AND HEADING TOWARD VANCOUVER ISLAND. IT IS ALONG THE JET STREAM
SOUTH OF THE GULF THAT THE SURFACE LOW IS GATHERING STRENGTH. THIS
LOW IS HEADING INTO THE SOUTHERN GULF TONIGHT AND WILL LOSE ITS
UPPER LEVEL SUPPORT WHEN IT DOES SO...LEAVING IT TO THEN SLOWLY
WEAKEN AND NOT MOVE MUCH THROUGH MONDAY.

&&

.MODEL DISCUSSION...

MODELS ARE IN QUITE GOOD AGREEMENT IN THE GULF OF ALASKA REGION
THROUGH TUESDAY AND ALL KEEP THE LOW FAR ENOUGH SOUTH TO KEEP MOST
OF THE PRECIPITATION FROM IT RELOCATED TO THE COAST. ONE AREA
WHERE THERE IS A LITTLE MORE DIVERGENCE IN THE MODELS IN WITH A
EASTERLY WAVE THAT WILL MOVE INTO THE COPPER RIVER BASIN FROM
CANADA ON SUNDAY NIGHT OR MONDAY AND THE STALL OUT AS IT MOVES
WESTWARD. THE NAM HAS BEEN THE MOST AGGRESSIVE MODEL WITH THIS
FEATURE BRINGING IT INTO THE SUSITNA VALLEY ON TUESDAY. THE GFS IS
NOT AS STRONG AND KEEPS IT MOSTLY IN THE COPPER RIVER BASIN.
IN THE BERING SEA THE MODELS ARE HOLDING TOGETHER WELL THROUGH
MONDAY WHEN THERE IS SOME DIFFERENCE IN HOW A LOW IN THE CENTRAL
BERING SEA IS ABSORBED INTO A SECOND LOW MOVING INTO THE AREA FROM
THE WEST. MODELS ALL SHOW THIS HAPPENING BUT BY TUESDAY AFTERNOON
THE ECMWF HAS THE MAIN LOW CENTER NEARLY 400 MILES FARTHER EAST
THAN THE NAM DOES. THE GFS AND GEM HAVE A MEDIAN POSITION BETWEEN
THE ECMWF AND NAM. THIS WILL MOSTLY IMPACT THE ALEUTIANS AND
BERING SEA AS SOUTHWEST MAINLAND ALASKA REMAINS UNDER HIGH
PRESSURE TUESDAY WITH THE LOW STILL WELL TO THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TRACK OF THE SURFACE LOW ACROSS THE FAR SOUTHERN GULF WILL
KEEP THE BULK OF THE IMPACTS CONFINED TO KODIAK ISLAND AND AREAS
ALONG THE COAST THROUGH SUNDAY AS A GALE FORCE FRONT MOVES
NORTHWESTWARD ACROSS THE GULF AND GRADUALLY WEAKENS...BRINGING
RAIN TO KODIAK ISLAND AND THE NORTH GULF COAST. AN EASTERLY WAVE
WILL THEN MOVE OVER THE COPPER RIVER BASIN ON SUNDAY NIGHT AND
SPREAD RAIN SHOWERS OVER THAT AREA THROUGH MONDAY...WITH THE CHANCE
FOR SHOWERS SPREADING TO THE MAT-SU AND COOK INLET REGIONS ON MONDAY
AS THE WAVE PROGRESSES WESTWARD.

FIRE WEATHER CONCERNS ACROSS THE ANCHORAGE BOWL AND MAT-SU WILL
BEGIN TO DIMINISH BY SUNDAY AS DAYTIME MINIMUM RH VALUES UNDERGO A
GRADUAL UPWARD TREND AS MID/HIGH LEVEL CLOUDS INCREASE AHEAD OF
THE EASTERLY WAVE POISED TO MOVE OVERHEAD SUNDAY NIGHT INTO
MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SCATTERED SHOWERS WILL CONTINUE TO DEVELOP THIS EVENING ALONG A
WEAK TROUGH AXIS SITUATED ACROSS THE SOUTHWEST MAINLAND. THE AXIS
SHIFTS SOUTH OVERNIGHT WITH PRECIPITATION ENDING BY SUNDAY
MORNING. EASTERLY FLOW ACROSS THE REGION SHIFTS TO THE NORTH ON
SUNDAY AS LOW PRESSURE REMAINS ACROSS THE GULF AND RIDGING SHIFTS
OVER THE EASTERN BERING. RELATIVELY DRIER CONDITIONS PERSIST
THROUGH MONDAY WITH THE LOW PRESSURE REMAINING NEARLY STATIONARY.
PRECIPITATION CHANCES INCREASE MONDAY NIGHT AS A WEAK EASTERLY
WAVE MOVES FROM THE GULF LOW...HOWEVER AMOUNTS WILL BE LIGHT AS
WEAK SURFACE RIDGING WORKS IN FROM THE EASTERN BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT MOVES INTO THE WESTERN BERING TONIGHT BRINGING
PRECIPITATION AND GUSTY WINDS ALONG THE BOUNDARY. THE FRONTAL
BOUNDARY MOVES INTO THE CENTRAL BERING/ALEUTIANS BY LATE SUNDAY
AND THEN REMAINS STATIONARY AS THE LOW CENTER MOVES WEST OF THE
PRIBILOF ISLANDS. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW
THROUGH THIS EVENT AS THE ASSOCIATED SURFACE LOW UNDERCUTS AN
UPPER RIDGE OVER THE BERING AND IS NOT STRONG ENOUGH TO PULL A
WARMER AIR MASS WITH IT. THIS SYSTEM WILL WEAKEN AS IT MOVES INTO
THE NORTHERN BERING ON MONDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING
THROUGH THE SOUTHERN BERING AND INTO THE GULF. MODEL DIFFERENCES
DEVELOP WITH THE EXACT TRACK OF THESE LOWS BY THE MIDDLE OF NEXT
WEEK AND WITH THE OPERATIONAL MODEL RUNS NOT BEING ABLE TO LOCK
DOWN EXACT LOW PLACEMENT A BLEND OF THE ENSEMBLES WAS USED FOR
THEIR POSITIONS. HOWEVER...THE PROGRESSIVE PATTERN WOULD BE
EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND AREAS ALONG THE
NORTH GULF COAST AS THESE LOWS PASS. WITH THE INSTABILITY OVER THE
MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN ALSO BE
EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 138 150 177 178.
FIRE WEATHER...RED FLAG WARNING 101 111 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DK





000
FXAK68 PAFC 260046 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
446 PM AKDT SAT APR 25 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL LOW IS OVER THE ALASKA PENINSULA THIS AFTERNOON
AS IT MAKES ITS WAY INTO THE GULF BY MONDAY. THIS IS LEAVING AN
UPPER LEVEL RIDGE OVER THE CENTRAL BERING SEA WITH ANOTHER UPPER
LEVEL RIDGE OVER THE YUKON...WHICH IS RAPIDLY DECAYING. THE JET
STREAM IS RUNNING OVER THE TOP OF THE ALEUTIANS AND THEN HEADING
SOUTH OF THE UPPER LEVEL LOW BEFORE TURNING BACK TO THE NORTHEAST
AND HEADING TOWARD VANCOUVER ISLAND. IT IS ALONG THE JET STREAM
SOUTH OF THE GULF THAT THE SURFACE LOW IS GATHERING STRENGTH. THIS
LOW IS HEADING INTO THE SOUTHERN GULF TONIGHT AND WILL LOSE ITS
UPPER LEVEL SUPPORT WHEN IT DOES SO...LEAVING IT TO THEN SLOWLY
WEAKEN AND NOT MOVE MUCH THROUGH MONDAY.

&&

.MODEL DISCUSSION...

MODELS ARE IN QUITE GOOD AGREEMENT IN THE GULF OF ALASKA REGION
THROUGH TUESDAY AND ALL KEEP THE LOW FAR ENOUGH SOUTH TO KEEP MOST
OF THE PRECIPITATION FROM IT RELOCATED TO THE COAST. ONE AREA
WHERE THERE IS A LITTLE MORE DIVERGENCE IN THE MODELS IN WITH A
EASTERLY WAVE THAT WILL MOVE INTO THE COPPER RIVER BASIN FROM
CANADA ON SUNDAY NIGHT OR MONDAY AND THE STALL OUT AS IT MOVES
WESTWARD. THE NAM HAS BEEN THE MOST AGGRESSIVE MODEL WITH THIS
FEATURE BRINGING IT INTO THE SUSITNA VALLEY ON TUESDAY. THE GFS IS
NOT AS STRONG AND KEEPS IT MOSTLY IN THE COPPER RIVER BASIN.
IN THE BERING SEA THE MODELS ARE HOLDING TOGETHER WELL THROUGH
MONDAY WHEN THERE IS SOME DIFFERENCE IN HOW A LOW IN THE CENTRAL
BERING SEA IS ABSORBED INTO A SECOND LOW MOVING INTO THE AREA FROM
THE WEST. MODELS ALL SHOW THIS HAPPENING BUT BY TUESDAY AFTERNOON
THE ECMWF HAS THE MAIN LOW CENTER NEARLY 400 MILES FARTHER EAST
THAN THE NAM DOES. THE GFS AND GEM HAVE A MEDIAN POSITION BETWEEN
THE ECMWF AND NAM. THIS WILL MOSTLY IMPACT THE ALEUTIANS AND
BERING SEA AS SOUTHWEST MAINLAND ALASKA REMAINS UNDER HIGH
PRESSURE TUESDAY WITH THE LOW STILL WELL TO THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TRACK OF THE SURFACE LOW ACROSS THE FAR SOUTHERN GULF WILL
KEEP THE BULK OF THE IMPACTS CONFINED TO KODIAK ISLAND AND AREAS
ALONG THE COAST THROUGH SUNDAY AS A GALE FORCE FRONT MOVES
NORTHWESTWARD ACROSS THE GULF AND GRADUALLY WEAKENS...BRINGING
RAIN TO KODIAK ISLAND AND THE NORTH GULF COAST. AN EASTERLY WAVE
WILL THEN MOVE OVER THE COPPER RIVER BASIN ON SUNDAY NIGHT AND
SPREAD RAIN SHOWERS OVER THAT AREA THROUGH MONDAY...WITH THE CHANCE
FOR SHOWERS SPREADING TO THE MAT-SU AND COOK INLET REGIONS ON MONDAY
AS THE WAVE PROGRESSES WESTWARD.

FIRE WEATHER CONCERNS ACROSS THE ANCHORAGE BOWL AND MAT-SU WILL
BEGIN TO DIMINISH BY SUNDAY AS DAYTIME MINIMUM RH VALUES UNDERGO A
GRADUAL UPWARD TREND AS MID/HIGH LEVEL CLOUDS INCREASE AHEAD OF
THE EASTERLY WAVE POISED TO MOVE OVERHEAD SUNDAY NIGHT INTO
MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SCATTERED SHOWERS WILL CONTINUE TO DEVELOP THIS EVENING ALONG A
WEAK TROUGH AXIS SITUATED ACROSS THE SOUTHWEST MAINLAND. THE AXIS
SHIFTS SOUTH OVERNIGHT WITH PRECIPITATION ENDING BY SUNDAY
MORNING. EASTERLY FLOW ACROSS THE REGION SHIFTS TO THE NORTH ON
SUNDAY AS LOW PRESSURE REMAINS ACROSS THE GULF AND RIDGING SHIFTS
OVER THE EASTERN BERING. RELATIVELY DRIER CONDITIONS PERSIST
THROUGH MONDAY WITH THE LOW PRESSURE REMAINING NEARLY STATIONARY.
PRECIPITATION CHANCES INCREASE MONDAY NIGHT AS A WEAK EASTERLY
WAVE MOVES FROM THE GULF LOW...HOWEVER AMOUNTS WILL BE LIGHT AS
WEAK SURFACE RIDGING WORKS IN FROM THE EASTERN BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT MOVES INTO THE WESTERN BERING TONIGHT BRINGING
PRECIPITATION AND GUSTY WINDS ALONG THE BOUNDARY. THE FRONTAL
BOUNDARY MOVES INTO THE CENTRAL BERING/ALEUTIANS BY LATE SUNDAY
AND THEN REMAINS STATIONARY AS THE LOW CENTER MOVES WEST OF THE
PRIBILOF ISLANDS. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW
THROUGH THIS EVENT AS THE ASSOCIATED SURFACE LOW UNDERCUTS AN
UPPER RIDGE OVER THE BERING AND IS NOT STRONG ENOUGH TO PULL A
WARMER AIR MASS WITH IT. THIS SYSTEM WILL WEAKEN AS IT MOVES INTO
THE NORTHERN BERING ON MONDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING
THROUGH THE SOUTHERN BERING AND INTO THE GULF. MODEL DIFFERENCES
DEVELOP WITH THE EXACT TRACK OF THESE LOWS BY THE MIDDLE OF NEXT
WEEK AND WITH THE OPERATIONAL MODEL RUNS NOT BEING ABLE TO LOCK
DOWN EXACT LOW PLACEMENT A BLEND OF THE ENSEMBLES WAS USED FOR
THEIR POSITIONS. HOWEVER...THE PROGRESSIVE PATTERN WOULD BE
EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND AREAS ALONG THE
NORTH GULF COAST AS THESE LOWS PASS. WITH THE INSTABILITY OVER THE
MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN ALSO BE
EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 138 150 177 178.
FIRE WEATHER...RED FLAG WARNING 101 111 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DK




000
FXAK68 PAFC 260046
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
446 PM AKDT SAT APR 25 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL LOW IS OVER THE ALASKA PENINSULA THIS AFTERNOON
AS IT MAKES ITS WAY INTO THE GULF BY MONDAY. THIS IS LEAVING AN
UPPER LEVEL RIDGE OVER THE CENTRAL BERING SEA WITH ANOTHER UPPER
LEVEL RIDGE OVER THE YUKON...WHICH IS RAPIDLY DECAYING. THE JET
STREAM IS RUNNING OVER THE TOP OF THE ALEUTIANS AND THEN HEADING
SOUTH OF THE UPPER LEVEL LOW BEFORE TURNING BACK TO THE NORTHEAST
AND HEADING TOWARD VANCOUVER ISLAND. IT IS ALONG THE JET STREAM
SOUTH OF THE GULF THAT THE SURFACE LOW IS GATHERING STRENGTH. THIS
LOW IS HEADING INTO THE SOUTHERN GULF TONIGHT AND WILL LOSE ITS
UPPER LEVEL SUPPORT WHEN IT DOES SO...LEAVING IT TO THEN SLOWLY
WEAKEN AND NOT MOVE MUCH THROUGH MONDAY.

&&

.MODEL DISCUSSION...

MODELS ARE IN QUITE GOOD AGREEMENT IN THE GULF OF ALASKA REGION
THROUGH TUESDAY AND ALL KEEP THE LOW FAR ENOUGH SOUTH TO KEEP MOST
OF THE PRECIPITATION FROM IT RELOCATED TO THE COAST. ONE AREA
WHERE THERE IS A LITTLE MORE DIVERGENCE IN THE MODELS IN WITH A
EASTERLY WAVE THAT WILL MOVE INTO THE COPPER RIVER BASIN FROM
CANADA ON SUNDAY NIGHT OR MONDAY AND THE STALL OUT AS IT MOVES
WESTWARD. THE NAM HAS BEEN THE MOST AGGRESSIVE MODEL WITH THIS
FEATURE BRINGING IT INTO THE SUSITNA VALLEY ON TUESDAY. THE GFS IS
NOT AS STRONG AND KEEPS IT MOSTLY IN THE COPPER RIVER BASIN.
IN THE BERING SEA THE MODELS ARE HOLDING TOGETHER WELL THROUGH
MONDAY WHEN THERE IS SOME DIFFERENCE IN HOW A LOW IN THE CENTRAL
BERING SEA IS ABSORBED INTO A SECOND LOW MOVING INTO THE AREA FROM
THE WEST. MODELS ALL SHOW THIS HAPPENING BUT BY TUESDAY AFTERNOON
THE ECMWF HAS THE MAIN LOW CENTER NEARLY 400 MILES FARTHER EAST
THAN THE NAM DOES. THE GFS AND GEM HAVE A MEDIAN POSITION BETWEEN
THE ECMWF AND NAM. THIS WILL MOSTLY IMPACT THE ALEUTIANS AND
BERING SEA AS SOUTHWEST MAINLAND ALASKA REMAINS UNDER HIGH
PRESSURE TUESDAY WITH THE LOW STILL WELL TO THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TRACK OF THE SURFACE LOW ACROSS THE FAR SOUTHERN GULF WILL
KEEP THE BULK OF THE IMPACTS CONFINED TO KODIAK ISLAND AND AREAS
ALONG THE COAST THROUGH SUNDAY AS A GALE FORCE FRONT MOVES
NORTHWESTWARD ACROSS THE GULF AND GRADUALLY WEAKENS...BRINGING
RAIN TO KODIAK ISLAND AND THE NORTH GULF COAST. AN EASTERLY WAVE
WILL THEN MOVE OVER THE COPPER RIVER BASIN ON SUNDAY NIGHT AND
SPREAD RAIN SHOWERS OVER THAT AREA THROUGH MONDAY...WITH THE CHANCE
FOR SHOWERS SPREADING TO THE MAT-SU AND COOK INLET REGIONS ON MONDAY
AS THE WAVE PROGRESSES WESTWARD.

FIRE WEATHER CONCERNS ACROSS THE ANCHORAGE BOWL AND MAT-SU WILL
BEGIN TO DIMINISH BY SUNDAY AS DAYTIME MINIMUM RH VALUES UNDERGO A
GRADUAL UPWARD TREND AS MID/HIGH LEVEL CLOUDS INCREASE AHEAD OF
THE EASTERLY WAVE POISED TO MOVE OVERHEAD SUNDAY NIGHT INTO
MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SCATTERED SHOWERS WILL CONTINUE TO DEVELOP THIS EVENING ALONG A
WEAK TROUGH AXIS SITUATED ACROSS THE SOUTHWEST MAINLAND. THE AXIS
SHIFTS SOUTH OVERNIGHT WITH PRECIPITATION ENDING BY SUNDAY
MORNING. EASTERLY FLOW ACROSS THE REGION SHIFTS TO THE NORTH ON
SUNDAY AS LOW PRESSURE REMAINS ACROSS THE GULF AND RIDGING SHIFTS
OVER THE EASTERN BERING. RELATIVELY DRIER CONDITIONS PERSIST
THROUGH MONDAY WITH THE LOW PRESSURE REMAINING NEARLY STATIONARY.
PRECIPITATION CHANCES INCREASE MONDAY NIGHT AS A WEAK EASTERLY
WAVE MOVES FROM THE GULF LOW...HOWEVER AMOUNTS WILL BE LIGHT AS
WEAK SURFACE RIDGING WORKS IN FROM THE EASTERN BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT MOVES INTO THE WESTERN BERING TONIGHT BRINGING
PRECIPITATION AND GUSTY WINDS ALONG THE BOUNDARY. THE FRONTAL
BOUNDARY MOVES INTO THE CENTRAL BERING/ALEUTIANS BY LATE SUNDAY
AND THEN REMAINS STATIONARY AS THE LOW CENTER MOVES WEST OF THE
PRIBILOF ISLANDS. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW
THROUGH THIS EVENT AS THE ASSOCIATED SURFACE LOW UNDERCUTS AN
UPPER RIDGE OVER THE BERING AND IS NOT STRONG ENOUGH TO PULL A
WARMER AIR MASS WITH IT. THIS SYSTEM WILL WEAKEN AS IT MOVES INTO
THE NORTHERN BERING ON MONDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING
THROUGH THE SOUTHERN BERING AND INTO THE GULF. MODEL DIFFERENCES
DEVELOP WITH THE EXACT TRACK OF THESE LOWS BY THE MIDDLE OF NEXT
WEEK AND WITH THE OPERATIONAL MODEL RUNS NOT BEING ABLE TO LOCK
DOWN EXACT LOW PLACEMENT A BLEND OF THE ENSEMBLES WAS USED FOR
THEIR POSITIONS. HOWEVER...THE PROGRESSIVE PATTERN WOULD BE
EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND AREAS ALONG THE
NORTH GULF COAST AS THESE LOWS PASS. WITH THE INSTABILITY OVER THE
MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN ALSO BE
EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 138 150 177 178.
FIRE WEATHER...RED FLAG WARNING 101 111 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...KH
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CB
LONG TERM...DK




000
FXAK68 PAFC 260046 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
446 PM AKDT SAT APR 25 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL LOW IS OVER THE ALASKA PENINSULA THIS AFTERNOON
AS IT MAKES ITS WAY INTO THE GULF BY MONDAY. THIS IS LEAVING AN
UPPER LEVEL RIDGE OVER THE CENTRAL BERING SEA WITH ANOTHER UPPER
LEVEL RIDGE OVER THE YUKON...WHICH IS RAPIDLY DECAYING. THE JET
STREAM IS RUNNING OVER THE TOP OF THE ALEUTIANS AND THEN HEADING
SOUTH OF THE UPPER LEVEL LOW BEFORE TURNING BACK TO THE NORTHEAST
AND HEADING TOWARD VANCOUVER ISLAND. IT IS ALONG THE JET STREAM
SOUTH OF THE GULF THAT THE SURFACE LOW IS GATHERING STRENGTH. THIS
LOW IS HEADING INTO THE SOUTHERN GULF TONIGHT AND WILL LOSE ITS
UPPER LEVEL SUPPORT WHEN IT DOES SO...LEAVING IT TO THEN SLOWLY
WEAKEN AND NOT MOVE MUCH THROUGH MONDAY.

&&

.MODEL DISCUSSION...

MODELS ARE IN QUITE GOOD AGREEMENT IN THE GULF OF ALASKA REGION
THROUGH TUESDAY AND ALL KEEP THE LOW FAR ENOUGH SOUTH TO KEEP MOST
OF THE PRECIPITATION FROM IT RELOCATED TO THE COAST. ONE AREA
WHERE THERE IS A LITTLE MORE DIVERGENCE IN THE MODELS IN WITH A
EASTERLY WAVE THAT WILL MOVE INTO THE COPPER RIVER BASIN FROM
CANADA ON SUNDAY NIGHT OR MONDAY AND THE STALL OUT AS IT MOVES
WESTWARD. THE NAM HAS BEEN THE MOST AGGRESSIVE MODEL WITH THIS
FEATURE BRINGING IT INTO THE SUSITNA VALLEY ON TUESDAY. THE GFS IS
NOT AS STRONG AND KEEPS IT MOSTLY IN THE COPPER RIVER BASIN.
IN THE BERING SEA THE MODELS ARE HOLDING TOGETHER WELL THROUGH
MONDAY WHEN THERE IS SOME DIFFERENCE IN HOW A LOW IN THE CENTRAL
BERING SEA IS ABSORBED INTO A SECOND LOW MOVING INTO THE AREA FROM
THE WEST. MODELS ALL SHOW THIS HAPPENING BUT BY TUESDAY AFTERNOON
THE ECMWF HAS THE MAIN LOW CENTER NEARLY 400 MILES FARTHER EAST
THAN THE NAM DOES. THE GFS AND GEM HAVE A MEDIAN POSITION BETWEEN
THE ECMWF AND NAM. THIS WILL MOSTLY IMPACT THE ALEUTIANS AND
BERING SEA AS SOUTHWEST MAINLAND ALASKA REMAINS UNDER HIGH
PRESSURE TUESDAY WITH THE LOW STILL WELL TO THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TRACK OF THE SURFACE LOW ACROSS THE FAR SOUTHERN GULF WILL
KEEP THE BULK OF THE IMPACTS CONFINED TO KODIAK ISLAND AND AREAS
ALONG THE COAST THROUGH SUNDAY AS A GALE FORCE FRONT MOVES
NORTHWESTWARD ACROSS THE GULF AND GRADUALLY WEAKENS...BRINGING
RAIN TO KODIAK ISLAND AND THE NORTH GULF COAST. AN EASTERLY WAVE
WILL THEN MOVE OVER THE COPPER RIVER BASIN ON SUNDAY NIGHT AND
SPREAD RAIN SHOWERS OVER THAT AREA THROUGH MONDAY...WITH THE CHANCE
FOR SHOWERS SPREADING TO THE MAT-SU AND COOK INLET REGIONS ON MONDAY
AS THE WAVE PROGRESSES WESTWARD.

FIRE WEATHER CONCERNS ACROSS THE ANCHORAGE BOWL AND MAT-SU WILL
BEGIN TO DIMINISH BY SUNDAY AS DAYTIME MINIMUM RH VALUES UNDERGO A
GRADUAL UPWARD TREND AS MID/HIGH LEVEL CLOUDS INCREASE AHEAD OF
THE EASTERLY WAVE POISED TO MOVE OVERHEAD SUNDAY NIGHT INTO
MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SCATTERED SHOWERS WILL CONTINUE TO DEVELOP THIS EVENING ALONG A
WEAK TROUGH AXIS SITUATED ACROSS THE SOUTHWEST MAINLAND. THE AXIS
SHIFTS SOUTH OVERNIGHT WITH PRECIPITATION ENDING BY SUNDAY
MORNING. EASTERLY FLOW ACROSS THE REGION SHIFTS TO THE NORTH ON
SUNDAY AS LOW PRESSURE REMAINS ACROSS THE GULF AND RIDGING SHIFTS
OVER THE EASTERN BERING. RELATIVELY DRIER CONDITIONS PERSIST
THROUGH MONDAY WITH THE LOW PRESSURE REMAINING NEARLY STATIONARY.
PRECIPITATION CHANCES INCREASE MONDAY NIGHT AS A WEAK EASTERLY
WAVE MOVES FROM THE GULF LOW...HOWEVER AMOUNTS WILL BE LIGHT AS
WEAK SURFACE RIDGING WORKS IN FROM THE EASTERN BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT MOVES INTO THE WESTERN BERING TONIGHT BRINGING
PRECIPITATION AND GUSTY WINDS ALONG THE BOUNDARY. THE FRONTAL
BOUNDARY MOVES INTO THE CENTRAL BERING/ALEUTIANS BY LATE SUNDAY
AND THEN REMAINS STATIONARY AS THE LOW CENTER MOVES WEST OF THE
PRIBILOF ISLANDS. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW
THROUGH THIS EVENT AS THE ASSOCIATED SURFACE LOW UNDERCUTS AN
UPPER RIDGE OVER THE BERING AND IS NOT STRONG ENOUGH TO PULL A
WARMER AIR MASS WITH IT. THIS SYSTEM WILL WEAKEN AS IT MOVES INTO
THE NORTHERN BERING ON MONDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING
THROUGH THE SOUTHERN BERING AND INTO THE GULF. MODEL DIFFERENCES
DEVELOP WITH THE EXACT TRACK OF THESE LOWS BY THE MIDDLE OF NEXT
WEEK AND WITH THE OPERATIONAL MODEL RUNS NOT BEING ABLE TO LOCK
DOWN EXACT LOW PLACEMENT A BLEND OF THE ENSEMBLES WAS USED FOR
THEIR POSITIONS. HOWEVER...THE PROGRESSIVE PATTERN WOULD BE
EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND AREAS ALONG THE
NORTH GULF COAST AS THESE LOWS PASS. WITH THE INSTABILITY OVER THE
MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN ALSO BE
EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 138 150 177 178.
FIRE WEATHER...RED FLAG WARNING 101 111 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DK




000
FXAK68 PAFC 260046 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
446 PM AKDT SAT APR 25 2015

.ANALYSIS AND UPPER LEVELS...

THE UPPER LEVEL LOW IS OVER THE ALASKA PENINSULA THIS AFTERNOON
AS IT MAKES ITS WAY INTO THE GULF BY MONDAY. THIS IS LEAVING AN
UPPER LEVEL RIDGE OVER THE CENTRAL BERING SEA WITH ANOTHER UPPER
LEVEL RIDGE OVER THE YUKON...WHICH IS RAPIDLY DECAYING. THE JET
STREAM IS RUNNING OVER THE TOP OF THE ALEUTIANS AND THEN HEADING
SOUTH OF THE UPPER LEVEL LOW BEFORE TURNING BACK TO THE NORTHEAST
AND HEADING TOWARD VANCOUVER ISLAND. IT IS ALONG THE JET STREAM
SOUTH OF THE GULF THAT THE SURFACE LOW IS GATHERING STRENGTH. THIS
LOW IS HEADING INTO THE SOUTHERN GULF TONIGHT AND WILL LOSE ITS
UPPER LEVEL SUPPORT WHEN IT DOES SO...LEAVING IT TO THEN SLOWLY
WEAKEN AND NOT MOVE MUCH THROUGH MONDAY.

&&

.MODEL DISCUSSION...

MODELS ARE IN QUITE GOOD AGREEMENT IN THE GULF OF ALASKA REGION
THROUGH TUESDAY AND ALL KEEP THE LOW FAR ENOUGH SOUTH TO KEEP MOST
OF THE PRECIPITATION FROM IT RELOCATED TO THE COAST. ONE AREA
WHERE THERE IS A LITTLE MORE DIVERGENCE IN THE MODELS IN WITH A
EASTERLY WAVE THAT WILL MOVE INTO THE COPPER RIVER BASIN FROM
CANADA ON SUNDAY NIGHT OR MONDAY AND THE STALL OUT AS IT MOVES
WESTWARD. THE NAM HAS BEEN THE MOST AGGRESSIVE MODEL WITH THIS
FEATURE BRINGING IT INTO THE SUSITNA VALLEY ON TUESDAY. THE GFS IS
NOT AS STRONG AND KEEPS IT MOSTLY IN THE COPPER RIVER BASIN.
IN THE BERING SEA THE MODELS ARE HOLDING TOGETHER WELL THROUGH
MONDAY WHEN THERE IS SOME DIFFERENCE IN HOW A LOW IN THE CENTRAL
BERING SEA IS ABSORBED INTO A SECOND LOW MOVING INTO THE AREA FROM
THE WEST. MODELS ALL SHOW THIS HAPPENING BUT BY TUESDAY AFTERNOON
THE ECMWF HAS THE MAIN LOW CENTER NEARLY 400 MILES FARTHER EAST
THAN THE NAM DOES. THE GFS AND GEM HAVE A MEDIAN POSITION BETWEEN
THE ECMWF AND NAM. THIS WILL MOSTLY IMPACT THE ALEUTIANS AND
BERING SEA AS SOUTHWEST MAINLAND ALASKA REMAINS UNDER HIGH
PRESSURE TUESDAY WITH THE LOW STILL WELL TO THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TRACK OF THE SURFACE LOW ACROSS THE FAR SOUTHERN GULF WILL
KEEP THE BULK OF THE IMPACTS CONFINED TO KODIAK ISLAND AND AREAS
ALONG THE COAST THROUGH SUNDAY AS A GALE FORCE FRONT MOVES
NORTHWESTWARD ACROSS THE GULF AND GRADUALLY WEAKENS...BRINGING
RAIN TO KODIAK ISLAND AND THE NORTH GULF COAST. AN EASTERLY WAVE
WILL THEN MOVE OVER THE COPPER RIVER BASIN ON SUNDAY NIGHT AND
SPREAD RAIN SHOWERS OVER THAT AREA THROUGH MONDAY...WITH THE CHANCE
FOR SHOWERS SPREADING TO THE MAT-SU AND COOK INLET REGIONS ON MONDAY
AS THE WAVE PROGRESSES WESTWARD.

FIRE WEATHER CONCERNS ACROSS THE ANCHORAGE BOWL AND MAT-SU WILL
BEGIN TO DIMINISH BY SUNDAY AS DAYTIME MINIMUM RH VALUES UNDERGO A
GRADUAL UPWARD TREND AS MID/HIGH LEVEL CLOUDS INCREASE AHEAD OF
THE EASTERLY WAVE POISED TO MOVE OVERHEAD SUNDAY NIGHT INTO
MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SCATTERED SHOWERS WILL CONTINUE TO DEVELOP THIS EVENING ALONG A
WEAK TROUGH AXIS SITUATED ACROSS THE SOUTHWEST MAINLAND. THE AXIS
SHIFTS SOUTH OVERNIGHT WITH PRECIPITATION ENDING BY SUNDAY
MORNING. EASTERLY FLOW ACROSS THE REGION SHIFTS TO THE NORTH ON
SUNDAY AS LOW PRESSURE REMAINS ACROSS THE GULF AND RIDGING SHIFTS
OVER THE EASTERN BERING. RELATIVELY DRIER CONDITIONS PERSIST
THROUGH MONDAY WITH THE LOW PRESSURE REMAINING NEARLY STATIONARY.
PRECIPITATION CHANCES INCREASE MONDAY NIGHT AS A WEAK EASTERLY
WAVE MOVES FROM THE GULF LOW...HOWEVER AMOUNTS WILL BE LIGHT AS
WEAK SURFACE RIDGING WORKS IN FROM THE EASTERN BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
A FRONT MOVES INTO THE WESTERN BERING TONIGHT BRINGING
PRECIPITATION AND GUSTY WINDS ALONG THE BOUNDARY. THE FRONTAL
BOUNDARY MOVES INTO THE CENTRAL BERING/ALEUTIANS BY LATE SUNDAY
AND THEN REMAINS STATIONARY AS THE LOW CENTER MOVES WEST OF THE
PRIBILOF ISLANDS. PRECIPITATION WILL BE A MIX OF RAIN AND SNOW
THROUGH THIS EVENT AS THE ASSOCIATED SURFACE LOW UNDERCUTS AN
UPPER RIDGE OVER THE BERING AND IS NOT STRONG ENOUGH TO PULL A
WARMER AIR MASS WITH IT. THIS SYSTEM WILL WEAKEN AS IT MOVES INTO
THE NORTHERN BERING ON MONDAY NIGHT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PROGRESSIVE PATTERN WILL DEVELOP EARLY NEXT WEEK AND CONTINUE
THROUGH THE REMAINDER OF THE WEEK WITH VARIOUS LOWS MOVING
THROUGH THE SOUTHERN BERING AND INTO THE GULF. MODEL DIFFERENCES
DEVELOP WITH THE EXACT TRACK OF THESE LOWS BY THE MIDDLE OF NEXT
WEEK AND WITH THE OPERATIONAL MODEL RUNS NOT BEING ABLE TO LOCK
DOWN EXACT LOW PLACEMENT A BLEND OF THE ENSEMBLES WAS USED FOR
THEIR POSITIONS. HOWEVER...THE PROGRESSIVE PATTERN WOULD BE
EXPECTED TO LEAD TO PRECIP FOR THE ALEUTIANS AND AREAS ALONG THE
NORTH GULF COAST AS THESE LOWS PASS. WITH THE INSTABILITY OVER THE
MORE INLAND LOCATIONS SHOWERY ACTIVITY CAN ALSO BE
EXPECTED...ESPECIALLY ALONG THE MOUNTAINS.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 138 150 177 178.
FIRE WEATHER...RED FLAG WARNING 101 111 145.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DK





    US Dept of Commerce
    National Oceanic and Atmospheric Administration
    National Weather Service
    1325 East West Highway
    Silver Spring, MD 20910
    Page Author: NWS Internet Services Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities