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000
FXAK68 PAFC 281302
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
502 AM AKDT THU MAY 28 2015

.ANALYSIS AND UPPER LEVELS...

AN UPPER LEVEL RIDGE OF HIGH PRESSURE IS CENTERED ACROSS THE
SOUTHERN ALCAN BORDER. THIS FEATURE IS KEEPING SOUTHCENTRAL DRY
WITH HIGH CLOUDS RIDING NORTHWARD ALONG A SHORTWAVE MOVING FROM
THE KENAI PENINSULA. A WEAK FRONT IS BRINGING RAIN ACROSS THE
SOUTHWEST MAINLAND WITH A RAIN BAND STRETCHING FROM JUST EAST OF
BETHEL TO NEAR ILIAMNA. THE MAIN WEATHER CHALLENGE IS MOVING INTO
THE SOUTHERN BERING THIS MORNING AS A STACKED LOW PRESSURE SYSTEM
MOVES FROM THE NORTH PACIFIC. THIS SYSTEM IS CURRENTLY BRINGING
GUSTY WINDS BETWEEN 20 TO 35 MPH WITH HIGHER GUSTS TO 45 MPH AND
RAIN WITH THE FRONTAL BOUNDARY ACROSS THE CENTRAL ALEUTIANS.

&&

.MODEL DISCUSSION...
MODEL AGREEMENT CONTINUES TO BE ABOVE AVERAGE WITH THE OVERNIGHT
PACKAGE. ONLY MINOR CHANGES WERE NEEDED THROUGH THE SHORT TERM
WITH THE USE OF THE NAM ACROSS THE EASTERN ZONES AND A COMBINATION
OF THE GFS AND ECMWF UTILIZED FOR THE WEST.


&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE WILL BUILD INTO SOUTH CENTRAL ALASKA TODAY AND
FRIDAY. THIS WILL USHER IN A WARMING AND DRYING TREND. ENOUGH
MOISTURE AND INSTABILITY REMAIN OVER THE COPPER RIVER BASIN
TODAY FOR A CONTINUED SLIGHT CHANCE OF AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS NORTH AND EAST OF GLENNALLEN. OFFSHORE
WINDS...GUSTY IN PREFERRED LOCATIONS...WILL DEVELOP TONIGHT AND
AGAIN FRIDAY NIGHT AS THE SURFACE HIGH PUSHES INLAND DURING THE
NIGHTTIME HOURS. THESE WILL WEAKEN OR EVEN REVERSE IN THE
AFTERNOON AS DAYTIME HEATING CREATES A THERMAL LOW INLAND.

&&

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

AFTER A FEW SHOWERS ASSOCIATED THIS MORNING WITH THE DECAYING
FRONT...SKIES WILL BECOME PARTLY CLOUDY. ON FRIDAY WARMER AND
DRIER CONDITIONS WILL PERSIST NEAR THE AK RANGE...BUT THE NEXT
FRONT WILL BRING A CHANCE OF RAIN TO AREAS WEST OF BETHEL AND
ALONG THE WESTERN CAPES.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE LOW CROSSING THE WESTERN ALEUTIANS AND ITS ASSOCIATED FRONT
WILL SPREAD GALE FORCE WINDS AND SUBSTANTIAL RAIN ACROSS THE
REGION TODAY AND TONIGHT. WINDS WILL BEGIN TO DIMINISH TO SMALL
CRAFT LEVELS ON FRI WITH RAIN CONTINUING OVER THE EASTERN
ALEUTIANS. THE WESTERN ALEUTIANS WILL BECOME SHOWERY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...170 172-179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...KH
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DS
LONG TERM...SB





000
FXAK68 PAFC 281302
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
502 AM AKDT THU MAY 28 2015

.ANALYSIS AND UPPER LEVELS...

AN UPPER LEVEL RIDGE OF HIGH PRESSURE IS CENTERED ACROSS THE
SOUTHERN ALCAN BORDER. THIS FEATURE IS KEEPING SOUTHCENTRAL DRY
WITH HIGH CLOUDS RIDING NORTHWARD ALONG A SHORTWAVE MOVING FROM
THE KENAI PENINSULA. A WEAK FRONT IS BRINGING RAIN ACROSS THE
SOUTHWEST MAINLAND WITH A RAIN BAND STRETCHING FROM JUST EAST OF
BETHEL TO NEAR ILIAMNA. THE MAIN WEATHER CHALLENGE IS MOVING INTO
THE SOUTHERN BERING THIS MORNING AS A STACKED LOW PRESSURE SYSTEM
MOVES FROM THE NORTH PACIFIC. THIS SYSTEM IS CURRENTLY BRINGING
GUSTY WINDS BETWEEN 20 TO 35 MPH WITH HIGHER GUSTS TO 45 MPH AND
RAIN WITH THE FRONTAL BOUNDARY ACROSS THE CENTRAL ALEUTIANS.

&&

.MODEL DISCUSSION...
MODEL AGREEMENT CONTINUES TO BE ABOVE AVERAGE WITH THE OVERNIGHT
PACKAGE. ONLY MINOR CHANGES WERE NEEDED THROUGH THE SHORT TERM
WITH THE USE OF THE NAM ACROSS THE EASTERN ZONES AND A COMBINATION
OF THE GFS AND ECMWF UTILIZED FOR THE WEST.


&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE WILL BUILD INTO SOUTH CENTRAL ALASKA TODAY AND
FRIDAY. THIS WILL USHER IN A WARMING AND DRYING TREND. ENOUGH
MOISTURE AND INSTABILITY REMAIN OVER THE COPPER RIVER BASIN
TODAY FOR A CONTINUED SLIGHT CHANCE OF AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS NORTH AND EAST OF GLENNALLEN. OFFSHORE
WINDS...GUSTY IN PREFERRED LOCATIONS...WILL DEVELOP TONIGHT AND
AGAIN FRIDAY NIGHT AS THE SURFACE HIGH PUSHES INLAND DURING THE
NIGHTTIME HOURS. THESE WILL WEAKEN OR EVEN REVERSE IN THE
AFTERNOON AS DAYTIME HEATING CREATES A THERMAL LOW INLAND.

&&

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

AFTER A FEW SHOWERS ASSOCIATED THIS MORNING WITH THE DECAYING
FRONT...SKIES WILL BECOME PARTLY CLOUDY. ON FRIDAY WARMER AND
DRIER CONDITIONS WILL PERSIST NEAR THE AK RANGE...BUT THE NEXT
FRONT WILL BRING A CHANCE OF RAIN TO AREAS WEST OF BETHEL AND
ALONG THE WESTERN CAPES.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE LOW CROSSING THE WESTERN ALEUTIANS AND ITS ASSOCIATED FRONT
WILL SPREAD GALE FORCE WINDS AND SUBSTANTIAL RAIN ACROSS THE
REGION TODAY AND TONIGHT. WINDS WILL BEGIN TO DIMINISH TO SMALL
CRAFT LEVELS ON FRI WITH RAIN CONTINUING OVER THE EASTERN
ALEUTIANS. THE WESTERN ALEUTIANS WILL BECOME SHOWERY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...170 172-179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...KH
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DS
LONG TERM...SB




000
FXAK68 PAFC 280305 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE STACKED LOW OVER THE BERING SEA WITH ANOTHER LOW
DEVELOPING SOUTH OF ATTU ISLAND THIS AFTERNOON. THE RIDGE REMAINS
IN PLACE OVER THE MAINLAND WITH A CLOSED LOW OVER THE PANHANDLE. THE
SOUTHERN LOW IS COUPLED WITH A 140 KNOT JET AND GOOD
BAROCLINICITY. THE CURRENT LOW IN THE BERING SEA WILL DIMINISH AS
IT FILLS AND LOSES OVERALL UPPER LEVEL SUPPORT. THE FRONT
ASSOCIATED WITH THE LOW IN THE BERING SEA WEAKENED OVERNIGHT BUT
IS RE-INTENSIFYING AS A SHORT WAVE TROUGH LIFTS THROUGH SOUTHWEST
ALASKA TODAY AND TONIGHT. THE PRECIPITATION WILL LIKELY NOT PUSH
INTO THE KUSKOKWIM VALLEY. THE SHORT WAVE TROUGH WILL PUSH INTO
THE RIDGE OF HIGH PRESSURE OVER THE INTERIOR TOMORROW. THE CLOSED
LOW OVER THE PANHANDLE KEEPING SOME MOISTURE SPILLING INTO THE
COPPER RIVER BASIN. THE AIR MASS IS UNSTABLE ENOUGH OVER THE
COPPER RIVER BASIN FOR SHOWERS BASIN WIDE AND ISOLATED THUNDERSTORMS
POSSIBLE NORTH AND EAST OF GLENNALLEN. IN BETWEEN THE FRONT AND
THE CLOSED LOW...MOSTLY CLEAR SKIES ARE PREVAILING.

&&

.MODEL DISCUSSION...
GIVEN THE STRONG LONG WAVE PATTERN...MODELS OVER THE NEXT FEW DAYS
ARE IN FANTASTIC AGREEMENT. THEREFORE...FORECAST CONFIDENCE IS
HIGH THROUGH FRIDAY.

THE RIDGE OVER THE STATE HAS REBOUNDED A BIT TODAY. CLEAR SKIES
REIGN OVER MOST OF THE INTERIOR OUTSIDE OF THE WEST COAST AND
COPPER RIVER BASIN. THERE WAS LITTLE STRATUS LAST NIGHT/THIS
MORNING AS WELL AS OPPOSED TO LAST NIGHT. A CLOSED LOW OVER THE
PANHANDLE IS KEEPING CLOUDS AND A CHANCE OF RAIN AND POSSIBLE
ISOLATED THUNDERSTORMS OVER THE COPPER RIVER BASIN. A SHORT WAVE
TROUGH IS RE-INVIGORATING THE FRONT ALONG THE WEST COAST AND WILL
LIFT NORTH AND EAST OVERNIGHT AND TOMORROW SPREADING SHOWERS AND
POSSIBLE THUNDERSTORMS INLAND. OVER SOUTH CENTRAL
ALASKA...THUNDERSTORM DEVELOPMENT WILL LIKELY BE LIMITED TO NORTH
OF GLENNALLEN. IN THE MEANTIME...A LOW STRENGTHENS IN THE WESTERN
ALEUTIAN ISLANDS THURSDAY. WINDS AROUND THE LOW WILL BE STRONG BUT
NOT EXPECTED TO PUSH INTO THE STORM FORCE RANGE AT THIS TIME.
PUSHED ACROSS THE BERING SEA AND ALEUTIAN ISLANDS WITH GOOD
BAROCLINICITY AND JET SUPPORT...A FRONT WILL MOVE INTO THE CENTRAL
BERING SEA THURSDAY AFTERNOON AND TO THE EASTERN BERING FRIDAY
AFTERNOON. THE RIDGE WILL BUILD OVER THE MAINLAND THURSDAY AND
FRIDAY WITH DAYTIME TEMPERATURES BECOMING 5 TO 10 DEGREES ABOVE
NORMAL AND POSSIBLY EVEN TO RECORD LEVELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE IS THE DOMINANT FEATURE OVER THE SOUTHCENTRAL WHICH
IS STARTING A DRYING TREND AND CAUSING THE CLEAR SKIES TO SPREAD.
THIS WILL CONTINUE THROUGH FRIDAY DROPPING RH VALUES TO AROUND 30
PERCENT IN THE COPPER RIVER BASIN AND SUSITNA VALLEY. UNDER THE
EFFECTS OF THE HIGH PRESSURE RAIN WILL BE LIMITED TO ISOLATED
SHOWERS MAINLY ALONG THE ALASKA RANGE. HOWEVER...ON THURSDAY A
TROUGH WILL PUSH THROUGH THE COPPER RIVER BASIN PROVIDING ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS. WINDS SHOULD BE LIGHT FOR
MOST OF THE SOUTHCENTRAL WITH SEA BREEZES DEVELOPING IN THE
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONTAL SYSTEM CURRENTLY STRETCHING ACROSS BRISTOL BAY AND
WESTERN ALASKA WILL SHIFT INLAND TONIGHT THEN NORTHEAST AND CLEAR
OF THE AREA THURSDAY MORNING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. CONDITIONS WILL DRY OUT QUICKLY WITH SHOWERS ENDING
THURSDAY AFTERNOON AS RIDGING BUILDS OVER SOUTHWEST ALASKA. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE COAST THURSDAY NIGHT HOWEVER
A STRENGTHENING UPPER LEVEL RIDGE INLAND SHOULD KEEP THE BULK OF
THE PRECIPITATION OFFSHORE MAINLY JUST IMPACTING THE WESTERN CAPES
AND ALASKA PENINSULA. THE FRONTAL SYSTEM WILL REMAIN STALLED NEAR
THE COAST FRIDAY THEN WEAKEN AND SHEAR APART SATURDAY. FURTHER
INLAND CONDITIONS WILL CONTINUE TO WARM AND DRY UNDER THE
PERSISTING UPPER LEVEL RIDGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE OLD BERING LOW NOW VERTICALLY STACKED WITH THE LARGE UPPER
LOW OFF OF THE KAMCHATKA PENINSULA WILL CONTINUE TO GRADUALLY FILL
AND WEAKEN TONIGHT AND DISSIPATE THURSDAY. A COLD UPPER LEVEL
TROUGH SWINGING IN FROM THE WEST COMBINED WITH A STRONG JET STREAM
WILL RAPIDLY STRENGTHEN THE NEW LOW DEVELOPING SOUTH OF THE
ALEUTIANS TODAY. THE ASSOCIATED RATHER STRONG FRONTAL SYSTEM WILL
APPROACH THE WESTERN AND CENTRAL ALEUTIANS TONIGHT BRINGING A SOLID
SWATH OF STRONG GALES WITH IT. THE SURFACE LOW WILL CROSS THE
ALEUTIAN AROUND THE KISKA AND AMCHITKA AREA THURSDAY MORNING.
WIDESPREAD GALES WILL FOLLOW THE LOW NORTH ACROSS THE BERING
THURSDAY AND FRIDAY BEFORE IT EVENTUALLY WEAKENS AND TRACKS OFF
TO THE NORTHWEST AND OUT OF THE AREA FRIDAY NIGHT AND SATURDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172 173 174 175 176 177 178 179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...SB





000
FXAK68 PAFC 280305 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE STACKED LOW OVER THE BERING SEA WITH ANOTHER LOW
DEVELOPING SOUTH OF ATTU ISLAND THIS AFTERNOON. THE RIDGE REMAINS
IN PLACE OVER THE MAINLAND WITH A CLOSED LOW OVER THE PANHANDLE. THE
SOUTHERN LOW IS COUPLED WITH A 140 KNOT JET AND GOOD
BAROCLINICITY. THE CURRENT LOW IN THE BERING SEA WILL DIMINISH AS
IT FILLS AND LOSES OVERALL UPPER LEVEL SUPPORT. THE FRONT
ASSOCIATED WITH THE LOW IN THE BERING SEA WEAKENED OVERNIGHT BUT
IS RE-INTENSIFYING AS A SHORT WAVE TROUGH LIFTS THROUGH SOUTHWEST
ALASKA TODAY AND TONIGHT. THE PRECIPITATION WILL LIKELY NOT PUSH
INTO THE KUSKOKWIM VALLEY. THE SHORT WAVE TROUGH WILL PUSH INTO
THE RIDGE OF HIGH PRESSURE OVER THE INTERIOR TOMORROW. THE CLOSED
LOW OVER THE PANHANDLE KEEPING SOME MOISTURE SPILLING INTO THE
COPPER RIVER BASIN. THE AIR MASS IS UNSTABLE ENOUGH OVER THE
COPPER RIVER BASIN FOR SHOWERS BASIN WIDE AND ISOLATED THUNDERSTORMS
POSSIBLE NORTH AND EAST OF GLENNALLEN. IN BETWEEN THE FRONT AND
THE CLOSED LOW...MOSTLY CLEAR SKIES ARE PREVAILING.

&&

.MODEL DISCUSSION...
GIVEN THE STRONG LONG WAVE PATTERN...MODELS OVER THE NEXT FEW DAYS
ARE IN FANTASTIC AGREEMENT. THEREFORE...FORECAST CONFIDENCE IS
HIGH THROUGH FRIDAY.

THE RIDGE OVER THE STATE HAS REBOUNDED A BIT TODAY. CLEAR SKIES
REIGN OVER MOST OF THE INTERIOR OUTSIDE OF THE WEST COAST AND
COPPER RIVER BASIN. THERE WAS LITTLE STRATUS LAST NIGHT/THIS
MORNING AS WELL AS OPPOSED TO LAST NIGHT. A CLOSED LOW OVER THE
PANHANDLE IS KEEPING CLOUDS AND A CHANCE OF RAIN AND POSSIBLE
ISOLATED THUNDERSTORMS OVER THE COPPER RIVER BASIN. A SHORT WAVE
TROUGH IS RE-INVIGORATING THE FRONT ALONG THE WEST COAST AND WILL
LIFT NORTH AND EAST OVERNIGHT AND TOMORROW SPREADING SHOWERS AND
POSSIBLE THUNDERSTORMS INLAND. OVER SOUTH CENTRAL
ALASKA...THUNDERSTORM DEVELOPMENT WILL LIKELY BE LIMITED TO NORTH
OF GLENNALLEN. IN THE MEANTIME...A LOW STRENGTHENS IN THE WESTERN
ALEUTIAN ISLANDS THURSDAY. WINDS AROUND THE LOW WILL BE STRONG BUT
NOT EXPECTED TO PUSH INTO THE STORM FORCE RANGE AT THIS TIME.
PUSHED ACROSS THE BERING SEA AND ALEUTIAN ISLANDS WITH GOOD
BAROCLINICITY AND JET SUPPORT...A FRONT WILL MOVE INTO THE CENTRAL
BERING SEA THURSDAY AFTERNOON AND TO THE EASTERN BERING FRIDAY
AFTERNOON. THE RIDGE WILL BUILD OVER THE MAINLAND THURSDAY AND
FRIDAY WITH DAYTIME TEMPERATURES BECOMING 5 TO 10 DEGREES ABOVE
NORMAL AND POSSIBLY EVEN TO RECORD LEVELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE IS THE DOMINANT FEATURE OVER THE SOUTHCENTRAL WHICH
IS STARTING A DRYING TREND AND CAUSING THE CLEAR SKIES TO SPREAD.
THIS WILL CONTINUE THROUGH FRIDAY DROPPING RH VALUES TO AROUND 30
PERCENT IN THE COPPER RIVER BASIN AND SUSITNA VALLEY. UNDER THE
EFFECTS OF THE HIGH PRESSURE RAIN WILL BE LIMITED TO ISOLATED
SHOWERS MAINLY ALONG THE ALASKA RANGE. HOWEVER...ON THURSDAY A
TROUGH WILL PUSH THROUGH THE COPPER RIVER BASIN PROVIDING ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS. WINDS SHOULD BE LIGHT FOR
MOST OF THE SOUTHCENTRAL WITH SEA BREEZES DEVELOPING IN THE
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONTAL SYSTEM CURRENTLY STRETCHING ACROSS BRISTOL BAY AND
WESTERN ALASKA WILL SHIFT INLAND TONIGHT THEN NORTHEAST AND CLEAR
OF THE AREA THURSDAY MORNING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. CONDITIONS WILL DRY OUT QUICKLY WITH SHOWERS ENDING
THURSDAY AFTERNOON AS RIDGING BUILDS OVER SOUTHWEST ALASKA. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE COAST THURSDAY NIGHT HOWEVER
A STRENGTHENING UPPER LEVEL RIDGE INLAND SHOULD KEEP THE BULK OF
THE PRECIPITATION OFFSHORE MAINLY JUST IMPACTING THE WESTERN CAPES
AND ALASKA PENINSULA. THE FRONTAL SYSTEM WILL REMAIN STALLED NEAR
THE COAST FRIDAY THEN WEAKEN AND SHEAR APART SATURDAY. FURTHER
INLAND CONDITIONS WILL CONTINUE TO WARM AND DRY UNDER THE
PERSISTING UPPER LEVEL RIDGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE OLD BERING LOW NOW VERTICALLY STACKED WITH THE LARGE UPPER
LOW OFF OF THE KAMCHATKA PENINSULA WILL CONTINUE TO GRADUALLY FILL
AND WEAKEN TONIGHT AND DISSIPATE THURSDAY. A COLD UPPER LEVEL
TROUGH SWINGING IN FROM THE WEST COMBINED WITH A STRONG JET STREAM
WILL RAPIDLY STRENGTHEN THE NEW LOW DEVELOPING SOUTH OF THE
ALEUTIANS TODAY. THE ASSOCIATED RATHER STRONG FRONTAL SYSTEM WILL
APPROACH THE WESTERN AND CENTRAL ALEUTIANS TONIGHT BRINGING A SOLID
SWATH OF STRONG GALES WITH IT. THE SURFACE LOW WILL CROSS THE
ALEUTIAN AROUND THE KISKA AND AMCHITKA AREA THURSDAY MORNING.
WIDESPREAD GALES WILL FOLLOW THE LOW NORTH ACROSS THE BERING
THURSDAY AND FRIDAY BEFORE IT EVENTUALLY WEAKENS AND TRACKS OFF
TO THE NORTHWEST AND OUT OF THE AREA FRIDAY NIGHT AND SATURDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172 173 174 175 176 177 178 179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...SB




000
FXAK68 PAFC 280305 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE STACKED LOW OVER THE BERING SEA WITH ANOTHER LOW
DEVELOPING SOUTH OF ATTU ISLAND THIS AFTERNOON. THE RIDGE REMAINS
IN PLACE OVER THE MAINLAND WITH A CLOSED LOW OVER THE PANHANDLE. THE
SOUTHERN LOW IS COUPLED WITH A 140 KNOT JET AND GOOD
BAROCLINICITY. THE CURRENT LOW IN THE BERING SEA WILL DIMINISH AS
IT FILLS AND LOSES OVERALL UPPER LEVEL SUPPORT. THE FRONT
ASSOCIATED WITH THE LOW IN THE BERING SEA WEAKENED OVERNIGHT BUT
IS RE-INTENSIFYING AS A SHORT WAVE TROUGH LIFTS THROUGH SOUTHWEST
ALASKA TODAY AND TONIGHT. THE PRECIPITATION WILL LIKELY NOT PUSH
INTO THE KUSKOKWIM VALLEY. THE SHORT WAVE TROUGH WILL PUSH INTO
THE RIDGE OF HIGH PRESSURE OVER THE INTERIOR TOMORROW. THE CLOSED
LOW OVER THE PANHANDLE KEEPING SOME MOISTURE SPILLING INTO THE
COPPER RIVER BASIN. THE AIR MASS IS UNSTABLE ENOUGH OVER THE
COPPER RIVER BASIN FOR SHOWERS BASIN WIDE AND ISOLATED THUNDERSTORMS
POSSIBLE NORTH AND EAST OF GLENNALLEN. IN BETWEEN THE FRONT AND
THE CLOSED LOW...MOSTLY CLEAR SKIES ARE PREVAILING.

&&

.MODEL DISCUSSION...
GIVEN THE STRONG LONG WAVE PATTERN...MODELS OVER THE NEXT FEW DAYS
ARE IN FANTASTIC AGREEMENT. THEREFORE...FORECAST CONFIDENCE IS
HIGH THROUGH FRIDAY.

THE RIDGE OVER THE STATE HAS REBOUNDED A BIT TODAY. CLEAR SKIES
REIGN OVER MOST OF THE INTERIOR OUTSIDE OF THE WEST COAST AND
COPPER RIVER BASIN. THERE WAS LITTLE STRATUS LAST NIGHT/THIS
MORNING AS WELL AS OPPOSED TO LAST NIGHT. A CLOSED LOW OVER THE
PANHANDLE IS KEEPING CLOUDS AND A CHANCE OF RAIN AND POSSIBLE
ISOLATED THUNDERSTORMS OVER THE COPPER RIVER BASIN. A SHORT WAVE
TROUGH IS RE-INVIGORATING THE FRONT ALONG THE WEST COAST AND WILL
LIFT NORTH AND EAST OVERNIGHT AND TOMORROW SPREADING SHOWERS AND
POSSIBLE THUNDERSTORMS INLAND. OVER SOUTH CENTRAL
ALASKA...THUNDERSTORM DEVELOPMENT WILL LIKELY BE LIMITED TO NORTH
OF GLENNALLEN. IN THE MEANTIME...A LOW STRENGTHENS IN THE WESTERN
ALEUTIAN ISLANDS THURSDAY. WINDS AROUND THE LOW WILL BE STRONG BUT
NOT EXPECTED TO PUSH INTO THE STORM FORCE RANGE AT THIS TIME.
PUSHED ACROSS THE BERING SEA AND ALEUTIAN ISLANDS WITH GOOD
BAROCLINICITY AND JET SUPPORT...A FRONT WILL MOVE INTO THE CENTRAL
BERING SEA THURSDAY AFTERNOON AND TO THE EASTERN BERING FRIDAY
AFTERNOON. THE RIDGE WILL BUILD OVER THE MAINLAND THURSDAY AND
FRIDAY WITH DAYTIME TEMPERATURES BECOMING 5 TO 10 DEGREES ABOVE
NORMAL AND POSSIBLY EVEN TO RECORD LEVELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE IS THE DOMINANT FEATURE OVER THE SOUTHCENTRAL WHICH
IS STARTING A DRYING TREND AND CAUSING THE CLEAR SKIES TO SPREAD.
THIS WILL CONTINUE THROUGH FRIDAY DROPPING RH VALUES TO AROUND 30
PERCENT IN THE COPPER RIVER BASIN AND SUSITNA VALLEY. UNDER THE
EFFECTS OF THE HIGH PRESSURE RAIN WILL BE LIMITED TO ISOLATED
SHOWERS MAINLY ALONG THE ALASKA RANGE. HOWEVER...ON THURSDAY A
TROUGH WILL PUSH THROUGH THE COPPER RIVER BASIN PROVIDING ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS. WINDS SHOULD BE LIGHT FOR
MOST OF THE SOUTHCENTRAL WITH SEA BREEZES DEVELOPING IN THE
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONTAL SYSTEM CURRENTLY STRETCHING ACROSS BRISTOL BAY AND
WESTERN ALASKA WILL SHIFT INLAND TONIGHT THEN NORTHEAST AND CLEAR
OF THE AREA THURSDAY MORNING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. CONDITIONS WILL DRY OUT QUICKLY WITH SHOWERS ENDING
THURSDAY AFTERNOON AS RIDGING BUILDS OVER SOUTHWEST ALASKA. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE COAST THURSDAY NIGHT HOWEVER
A STRENGTHENING UPPER LEVEL RIDGE INLAND SHOULD KEEP THE BULK OF
THE PRECIPITATION OFFSHORE MAINLY JUST IMPACTING THE WESTERN CAPES
AND ALASKA PENINSULA. THE FRONTAL SYSTEM WILL REMAIN STALLED NEAR
THE COAST FRIDAY THEN WEAKEN AND SHEAR APART SATURDAY. FURTHER
INLAND CONDITIONS WILL CONTINUE TO WARM AND DRY UNDER THE
PERSISTING UPPER LEVEL RIDGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE OLD BERING LOW NOW VERTICALLY STACKED WITH THE LARGE UPPER
LOW OFF OF THE KAMCHATKA PENINSULA WILL CONTINUE TO GRADUALLY FILL
AND WEAKEN TONIGHT AND DISSIPATE THURSDAY. A COLD UPPER LEVEL
TROUGH SWINGING IN FROM THE WEST COMBINED WITH A STRONG JET STREAM
WILL RAPIDLY STRENGTHEN THE NEW LOW DEVELOPING SOUTH OF THE
ALEUTIANS TODAY. THE ASSOCIATED RATHER STRONG FRONTAL SYSTEM WILL
APPROACH THE WESTERN AND CENTRAL ALEUTIANS TONIGHT BRINGING A SOLID
SWATH OF STRONG GALES WITH IT. THE SURFACE LOW WILL CROSS THE
ALEUTIAN AROUND THE KISKA AND AMCHITKA AREA THURSDAY MORNING.
WIDESPREAD GALES WILL FOLLOW THE LOW NORTH ACROSS THE BERING
THURSDAY AND FRIDAY BEFORE IT EVENTUALLY WEAKENS AND TRACKS OFF
TO THE NORTHWEST AND OUT OF THE AREA FRIDAY NIGHT AND SATURDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172 173 174 175 176 177 178 179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...SB




000
FXAK68 PAFC 280023
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE STACKED LOW OVER THE BERING SEA WITH ANOTHER LOW
DEVELOPING SOUTH OF ATTU ISLAND THIS AFTERNOON. THE RIDGE REMAINS
IN PLACE OVER THE MAINLAND WITH A CLOSED LOW OVER THE PANHANDLE. THE
SOUTHERN LOW IS COUPLED WITH A 140 KNOT JET AND GOOD
BAROCLINICITY. THE CURRENT LOW IN THE BERING SEA WILL DIMINISH AS
IT FILLS AND LOSES OVERALL UPPER LEVEL SUPPORT. THE FRONT
ASSOCIATED WITH THE LOW IN THE BERING SEA WEAKENED OVERNIGHT BUT
IS RE-INTENSIFYING AS A SHORT WAVE TROUGH LIFTS THROUGH SOUTHWEST
ALASKA TODAY AND TONIGHT. THE PRECIPITATION WILL LIKELY NOT PUSH
INTO THE KUSKOKWIM VALLEY. THE SHORT WAVE TROUGH WILL PUSH INTO
THE RIDGE OF HIGH PRESSURE OVER THE INTERIOR TOMORROW. THE CLOSED
LOW OVER THE PANHANDLE KEEPING SOME MOISTURE SPILLING INTO THE
COPPER RIVER BASIN. THE AIR MASS IS UNSTABLE ENOUGH OVER THE
COPPER RIVER BASIN FOR SHOWERS BASIN WIDE AND ISOLATED THUNDERSTORMS
POSSIBLE NORTH AND EAST OF GLENNALLEN. IN BETWEEN THE FRONT AND
THE CLOSED LOW...MOSTLY CLEAR SKIES ARE PREVAILING.

&&

.MODEL DISCUSSION...
GIVEN THE STRONG LONG WAVE PATTERN...MODELS OVER THE NEXT FEW DAYS
ARE IN FANTASTIC AGREEMENT. THEREFORE...FORECAST CONFIDENCE IS
HIGH THROUGH FRIDAY.

THE RIDGE OVER THE STATE HAS REBOUNDED A BIT TODAY. CLEAR SKIES
REIGN OVER MOST OF THE INTERIOR OUTSIDE OF THE WEST COAST AND
COPPER RIVER BASIN. THERE WAS LITTLE STRATUS LAST NIGHT/THIS
MORNING AS WELL AS OPPOSED TO LAST NIGHT. A CLOSED LOW OVER THE
PANHANDLE IS KEEPING CLOUDS AND A CHANCE OF RAIN AND POSSIBLE
ISOLATED THUNDERSTORMS OVER THE COPPER RIVER BASIN. A SHORT WAVE
TROUGH IS RE-INVIGORATING THE FRONT ALONG THE WEST COAST AND WILL
LIFT NORTH AND EAST OVERNIGHT AND TOMORROW SPREADING SHOWERS AND
POSSIBLE THUNDERSTORMS INLAND. OVER SOUTH CENTRAL
ALASKA...THUNDERSTORM DEVELOPMENT WILL LIKELY BE LIMITED TO NORTH
OF GLENNALLEN. IN THE MEANTIME...A LOW STRENGTHENS IN THE WESTERN
ALEUTIAN ISLANDS THURSDAY. WINDS AROUND THE LOW WILL BE STRONG BUT
NOT EXPECTED TO PUSH INTO THE STORM FORCE RANGE AT THIS TIME.
PUSHED ACROSS THE BERING SEA AND ALEUTIAN ISLANDS WITH GOOD
BAROCLINICITY AND JET SUPPORT...A FRONT WILL MOVE INTO THE CENTRAL
BERING SEA THURSDAY AFTERNOON AND TO THE EASTERN BERING FRIDAY
AFTERNOON. THE TO RETROGRADE TO THE WEST FRIDAY. THE STRENGTH OF
THIS LOW TO STRENGTHEN THE RIDGE OVER THE MAINLAND FRIDAY WITH
DAYTIME TEMPERATURES BECOMING 5 TO 10 DEGREES ABOVE NORMAL AND
POSSIBLY EVEN TO RECORD LEVELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE IS THE DOMINANT FEATURE OVER THE SOUTHCENTRAL WHICH
IS STARTING A DRYING TREND AND CAUSING THE CLEAR SKIES TO SPREAD.
THIS WILL CONTINUE THROUGH FRIDAY DROPPING RH VALUES TO AROUND 30
PERCENT IN THE COPPER RIVER BASIN AND SUSITNA VALLEY. UNDER THE
EFFECTS OF THE HIGH PRESSURE RAIN WILL BE LIMITED TO ISOLATED
SHOWERS MAINLY ALONG THE ALASKA RANGE. HOWEVER...ON THURSDAY A
TROUGH WILL PUSH THROUGH THE COPPER RIVER BASIN PROVIDING ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS. WINDS SHOULD BE LIGHT FOR
MOST OF THE SOUTHCENTRAL WITH SEA BREEZES DEVELOPING IN THE
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONTAL SYSTEM CURRENTLY STRETCHING ACROSS BRISTOL BAY AND
WESTERN ALASKA WILL SHIFT INLAND TONIGHT THEN NORTHEAST AND CLEAR
OF THE AREA THURSDAY MORNING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. CONDITIONS WILL DRY OUT QUICKLY WITH SHOWERS ENDING
THURSDAY AFTERNOON AS RIDGING BUILDS OVER SOUTHWEST ALASKA. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE COAST THURSDAY NIGHT HOWEVER
A STRENGTHENING UPPER LEVEL RIDGE INLAND SHOULD KEEP THE BULK OF
THE PRECIPITATION OFFSHORE MAINLY JUST IMPACTING THE WESTERN CAPES
AND ALASKA PENINSULA. THE FRONTAL SYSTEM WILL REMAIN STALLED NEAR
THE COAST FRIDAY THEN WEAKEN AND SHEAR APART SATURDAY. FURTHER
INLAND CONDITIONS WILL CONTINUE TO WARM AND DRY UNDER THE
PERSISTING UPPER LEVEL RIDGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE OLD BERING LOW NOW VERTICALLY STACKED WITH THE LARGE UPPER
LOW OFF OF THE KAMCHATKA PENINSULA WILL CONTINUE TO GRADUALLY FILL
AND WEAKEN TONIGHT AND DISSIPATE THURSDAY. A COLD UPPER LEVEL
TROUGH SWINGING IN FROM THE WEST COMBINED WITH A STRONG JET STREAM
WILL RAPIDLY STRENGTHEN THE NEW LOW DEVELOPING SOUTH OF THE
ALEUTIANS TODAY. THE ASSOCIATED RATHER STRONG FRONTAL SYSTEM WILL
APPROACH THE WESTERN AND CENTRAL ALEUTIANS TONIGHT BRINGING A SOLID
SWATH OF STRONG GALES WITH IT. THE SURFACE LOW WILL CROSS THE
ALEUTIAN AROUND THE KISKA AND AMCHITKA AREA THURSDAY MORNING.
WIDESPREAD GALES WILL FOLLOW THE LOW NORTH ACROSS THE BERING
THURSDAY AND FRIDAY BEFORE IT EVENTUALLY WEAKENS AND TRACKS OFF
TO THE NORTHWEST AND OUT OF THE AREA FRIDAY NIGHT AND SATURDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172 173 174 175 176 177 178 179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...SB




000
FXAK68 PAFC 280023
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
423 PM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A LARGE STACKED LOW OVER THE BERING SEA WITH ANOTHER LOW
DEVELOPING SOUTH OF ATTU ISLAND THIS AFTERNOON. THE RIDGE REMAINS
IN PLACE OVER THE MAINLAND WITH A CLOSED LOW OVER THE PANHANDLE. THE
SOUTHERN LOW IS COUPLED WITH A 140 KNOT JET AND GOOD
BAROCLINICITY. THE CURRENT LOW IN THE BERING SEA WILL DIMINISH AS
IT FILLS AND LOSES OVERALL UPPER LEVEL SUPPORT. THE FRONT
ASSOCIATED WITH THE LOW IN THE BERING SEA WEAKENED OVERNIGHT BUT
IS RE-INTENSIFYING AS A SHORT WAVE TROUGH LIFTS THROUGH SOUTHWEST
ALASKA TODAY AND TONIGHT. THE PRECIPITATION WILL LIKELY NOT PUSH
INTO THE KUSKOKWIM VALLEY. THE SHORT WAVE TROUGH WILL PUSH INTO
THE RIDGE OF HIGH PRESSURE OVER THE INTERIOR TOMORROW. THE CLOSED
LOW OVER THE PANHANDLE KEEPING SOME MOISTURE SPILLING INTO THE
COPPER RIVER BASIN. THE AIR MASS IS UNSTABLE ENOUGH OVER THE
COPPER RIVER BASIN FOR SHOWERS BASIN WIDE AND ISOLATED THUNDERSTORMS
POSSIBLE NORTH AND EAST OF GLENNALLEN. IN BETWEEN THE FRONT AND
THE CLOSED LOW...MOSTLY CLEAR SKIES ARE PREVAILING.

&&

.MODEL DISCUSSION...
GIVEN THE STRONG LONG WAVE PATTERN...MODELS OVER THE NEXT FEW DAYS
ARE IN FANTASTIC AGREEMENT. THEREFORE...FORECAST CONFIDENCE IS
HIGH THROUGH FRIDAY.

THE RIDGE OVER THE STATE HAS REBOUNDED A BIT TODAY. CLEAR SKIES
REIGN OVER MOST OF THE INTERIOR OUTSIDE OF THE WEST COAST AND
COPPER RIVER BASIN. THERE WAS LITTLE STRATUS LAST NIGHT/THIS
MORNING AS WELL AS OPPOSED TO LAST NIGHT. A CLOSED LOW OVER THE
PANHANDLE IS KEEPING CLOUDS AND A CHANCE OF RAIN AND POSSIBLE
ISOLATED THUNDERSTORMS OVER THE COPPER RIVER BASIN. A SHORT WAVE
TROUGH IS RE-INVIGORATING THE FRONT ALONG THE WEST COAST AND WILL
LIFT NORTH AND EAST OVERNIGHT AND TOMORROW SPREADING SHOWERS AND
POSSIBLE THUNDERSTORMS INLAND. OVER SOUTH CENTRAL
ALASKA...THUNDERSTORM DEVELOPMENT WILL LIKELY BE LIMITED TO NORTH
OF GLENNALLEN. IN THE MEANTIME...A LOW STRENGTHENS IN THE WESTERN
ALEUTIAN ISLANDS THURSDAY. WINDS AROUND THE LOW WILL BE STRONG BUT
NOT EXPECTED TO PUSH INTO THE STORM FORCE RANGE AT THIS TIME.
PUSHED ACROSS THE BERING SEA AND ALEUTIAN ISLANDS WITH GOOD
BAROCLINICITY AND JET SUPPORT...A FRONT WILL MOVE INTO THE CENTRAL
BERING SEA THURSDAY AFTERNOON AND TO THE EASTERN BERING FRIDAY
AFTERNOON. THE TO RETROGRADE TO THE WEST FRIDAY. THE STRENGTH OF
THIS LOW TO STRENGTHEN THE RIDGE OVER THE MAINLAND FRIDAY WITH
DAYTIME TEMPERATURES BECOMING 5 TO 10 DEGREES ABOVE NORMAL AND
POSSIBLY EVEN TO RECORD LEVELS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE IS THE DOMINANT FEATURE OVER THE SOUTHCENTRAL WHICH
IS STARTING A DRYING TREND AND CAUSING THE CLEAR SKIES TO SPREAD.
THIS WILL CONTINUE THROUGH FRIDAY DROPPING RH VALUES TO AROUND 30
PERCENT IN THE COPPER RIVER BASIN AND SUSITNA VALLEY. UNDER THE
EFFECTS OF THE HIGH PRESSURE RAIN WILL BE LIMITED TO ISOLATED
SHOWERS MAINLY ALONG THE ALASKA RANGE. HOWEVER...ON THURSDAY A
TROUGH WILL PUSH THROUGH THE COPPER RIVER BASIN PROVIDING ENOUGH
INSTABILITY FOR ISOLATED THUNDERSTORMS. WINDS SHOULD BE LIGHT FOR
MOST OF THE SOUTHCENTRAL WITH SEA BREEZES DEVELOPING IN THE
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONTAL SYSTEM CURRENTLY STRETCHING ACROSS BRISTOL BAY AND
WESTERN ALASKA WILL SHIFT INLAND TONIGHT THEN NORTHEAST AND CLEAR
OF THE AREA THURSDAY MORNING AS AN UPPER LEVEL TROUGH SWINGS
THROUGH. CONDITIONS WILL DRY OUT QUICKLY WITH SHOWERS ENDING
THURSDAY AFTERNOON AS RIDGING BUILDS OVER SOUTHWEST ALASKA. THE
NEXT FRONTAL SYSTEM WILL APPROACH THE COAST THURSDAY NIGHT HOWEVER
A STRENGTHENING UPPER LEVEL RIDGE INLAND SHOULD KEEP THE BULK OF
THE PRECIPITATION OFFSHORE MAINLY JUST IMPACTING THE WESTERN CAPES
AND ALASKA PENINSULA. THE FRONTAL SYSTEM WILL REMAIN STALLED NEAR
THE COAST FRIDAY THEN WEAKEN AND SHEAR APART SATURDAY. FURTHER
INLAND CONDITIONS WILL CONTINUE TO WARM AND DRY UNDER THE
PERSISTING UPPER LEVEL RIDGE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE OLD BERING LOW NOW VERTICALLY STACKED WITH THE LARGE UPPER
LOW OFF OF THE KAMCHATKA PENINSULA WILL CONTINUE TO GRADUALLY FILL
AND WEAKEN TONIGHT AND DISSIPATE THURSDAY. A COLD UPPER LEVEL
TROUGH SWINGING IN FROM THE WEST COMBINED WITH A STRONG JET STREAM
WILL RAPIDLY STRENGTHEN THE NEW LOW DEVELOPING SOUTH OF THE
ALEUTIANS TODAY. THE ASSOCIATED RATHER STRONG FRONTAL SYSTEM WILL
APPROACH THE WESTERN AND CENTRAL ALEUTIANS TONIGHT BRINGING A SOLID
SWATH OF STRONG GALES WITH IT. THE SURFACE LOW WILL CROSS THE
ALEUTIAN AROUND THE KISKA AND AMCHITKA AREA THURSDAY MORNING.
WIDESPREAD GALES WILL FOLLOW THE LOW NORTH ACROSS THE BERING
THURSDAY AND FRIDAY BEFORE IT EVENTUALLY WEAKENS AND TRACKS OFF
TO THE NORTHWEST AND OUT OF THE AREA FRIDAY NIGHT AND SATURDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7 - SATURDAY THROUGH WEDNESDAY)...
A VERY HIGH AMPLITUDE PATTERN WILL BE IN PLACE ON SATURDAY WITH A
BLOCKING RIDGE EXTENDING FROM THE HIGH ARCTIC (BEAUFORT/CHUKCHI SEAS)
SOUTHWARD ACROSS MAINLAND ALASKA AND DOWN INTO THE NORTHEAST PACIFIC.
UPSTREAM A CORRESPONDING TROUGH WILL EXTEND FROM EASTERN RUSSIA
SOUTHEASTWARD ACROSS THE BERING SEA AND ALEUTIANS TO THE NORTH-
CENTRAL PACIFIC. THE STORM TRACK WILL REMAIN ON THE WESTERN EDGE
OF THIS TROUGH...MAINLY AFFECTING THE FAR WESTERN BERING SEA AND
WESTERN ALEUTIANS. THE REST OF THE REGION WILL BE DOMINATED BY
GENERALLY WEAK FLOW AND FORCING.

THE BIG HEADLINE FOR THIS WEEKEND INTO EARLY NEXT WEEK WILL BE
HOT AND DRY CONDITIONS ACROSS SOUTHCENTRAL AND INTERIOR SOUTHWEST
ALASKA. THE KEY TO THIS WARMTH IS ENERGY DROPPING OUT OF THE
CANADIAN ARCTIC SLIDING DOWN THE EAST SIDE OF THE UPPER RIDGE
ACROSS EASTERN MAINLAND ALASKA. THIS WILL ADVECT DRIER AIR FROM
THE INTERIOR AND HINDER OR PREVENT FORMATION OF SEA BREEZES ALONG
THE GULF COAST. IF THESE UPPER WAVES ACTUALLY TRACK SOUTHWARD INTO
THE GULF THERE IS POTENTIAL FOR GUSTY NORTHERLY WINDS WHICH WOULD
RESULT IN EVEN HOTTER AND DRIER CONDITIONS. THERE ARE MODEL
DIFFERENCES IN THE TIMING AND TRACK OF UPPER LEVEL WAVES. THUS IT
IS DIFFICULT TO NAIL DOWN THE DETAILS AT THIS POINT IN TIME.
HOWEVER...CHANCES ARE THAT CRITICAL FIRE WEATHER CONDITIONS WILL
DEVELOP SOMETIME OVER THE WEEKEND.

AS STEADY PARADE OF UPPER WAVES ALONG THE EASTERN PERIPHERY OF THE
RIDGE WILL CAUSE IT TO RETROGRADE WESTWARD EARLY NEXT WEEK. THIS
WILL RESULT IN A COOLING TREND BEGINNING TUESDAY ALONG WITH A
MORE FAVORABLE CONDITIONS FOR SHOWERS AS WE HEAD THROUGH THE
WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170 172 173 174 175 176 177 178 179 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...SB




000
FXAK68 PAFC 271249
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
449 AM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...

THE MASSIVE UPPER LEVEL RIDGE CENTERED OVER THE ALCAN IS BEING
UNDERCUT BY A SMALL UPPER LOW CURRENTLY OVER SOUTHEAST AK THIS
MORNING. A LARGER UPPER LOW ENCOMPASSES MOST OF THE BERING. AT
THE SURFACE...A SLOWLY WEAKENING LOW IS OVER THE WESTERN BERING AS
ITS ASSOCIATED SHOWER PRODUCING FRONT IS OVER SW AK. HIGH
PRESSURE OVER THE GULF EXTENDS OVER MUCH OF THE MAINLAND...
INTERRUPTED ONLY BY A THERMAL TROUGH DRAPED NORTH OF THE AK RANGE
AND NOSING INTO THE COPPER RIVER BASIN.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE RIDGE OVER MAINLAND AK WILL
REBUILD TODAY. AN UPPER TROUGH WILL RIPPLE ALONG ITS WESTERN
FLANK THU AND FLATTEN THE NORTHERN EXTENT OF THE RIDGE FRI NIGHT.
THIS WILL ALLOW THE SW AK FRONT TO WEAKEN AND MOVE EAST AS AN
AREA OF MOISTURE...REACHING THE ALCAN BY FRI MORNING. THE THERMAL
TROUGH WILL EDGE ACROSS THE AK RANGE INTO THE COPPER RIVER BASIN
THIS AFTERNOON AND THEN MAKE A MORE SUBSTANTIAL INTRUSION OVER
MOST OF THE COPPER RIVER BASIN ON THU WHERE IT WILL INTERACT WITH
THE MOISTURE REMNANT OF THE SW AK FRONT. MODELS ARE ALSO IN
AGREEMENT THAT THE CURRENT BERING LOW WILL DISSIPATE TONIGHT...BUT
AN INTENSIFYING NORTH PACIFIC LOW WILL REACH THE ALEUTIANS BY THU
MORNING AND THEN CROSS INTO THE BERING. THE FORECASTS UTILIZE THE
EC IN THE WEST AND THE NAM IN THE EAST...THE LATTER HAVING PERFORMED
WELL IN PINPOINTING POSSIBLE THUNDERSTORM AREAS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE WILL BUILD OVER SOUTH CENTRAL ALASKA TODAY AND
THURSDAY WITH A WARMING TREND ON TAP. SOME LINGERING MOISTURE
OVER THE COPPER RIVER BASIN WILL KEEP A CHANCE OF SHOWERS FOR THAT
AREA...AND A SLIGHT RISK OF DIURNAL THUNDERSTORMS WITH SLIGHTLY
UNSTABLE CONDITIONS. AN UPPER LEVEL SHORT WAVE ASSOCIATED WITH THE
BERING LOW WILL SKIRT THE AREA TO THE WEST AND THEN NORTH ON
THURSDAY...HELPING TO KEEP THE CONDITIONS UNSTABLE IN THE COPPER
RIVER BASIN.

&&

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

A STALLED AND WEAKENING FRONTAL ZONE WILL REMAIN OVER THE
SOUTHWEST COAST THROUGH THIS EVENING BEFORE WEAKENING. MOST OF
THE RAINFALL ASSOCIATED WITH THIS WILL BE OVER THE KUSKOKWIM DELTA
AND WESTERN CAPES. INLAND LOCATIONS WILL REMAIN DRY AND WARMER
TODAY. ON THURSDAY...THE WEAKENED UPPER LEVEL LOW WILL MOVE
EAST...SPREADING SOME MID LEVEL CLOUDS AND A FEW SHOWERS ACROSS
THE LOWER KUSKOKWIM VALLEY AND BRISTOL BAY...BUT MOST LOCATIONS
WILL JUST REMAIN DRY. HIGH PRESSURE ALOFT WILL THEN SETTLE IN
THROUGH FRIDAY BEFORE ANOTHER FRONT TRACKS TOWARD THE COAST.
PATCHY OVERNIGHT FOG WILL GENERALLY REMAIN RELEGATED TO COASTAL
LOCATIONS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

A BROAD LOW OVER THE WESTERN BERING...WITH THE ASSOCIATED FRONT
OVER THE EASTERN BERING...WILL WEAKEN TODAY BEFORE A STRONG LOW
FOR THIS TIME OF YEAR MOVES INTO THE WESTERN BERING AND ALEUTIANS
TONIGHT AND THURSDAY. THE LOW IS EXPECTED TO TRACK IN THE VICINITY
OF KISKA...WITH STRONG SOUTH TO SOUTHEAST MAX GALE FORCE WINDS
IMPACTING THE WESTERN AND CENTRAL ALEUTIANS. STORM FORCE WIND
GUSTS WILL ALSO IMPACT THE REGION...WITH GUSTY WINDS EXTENDING TO
THE EASTERN ALEUTIANS AS THE LOW MOVES NORTH ON THURSDAY AND
THURSDAY NIGHT. MODERATE TO HEAVY RAIN WILL ALSO SPREAD OVER THE
BERING AS THE FRONTAL ZONE TRACKS EAST.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY...AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE...BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA...SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF. THIS WOULD ESSENTIALLY RESULT IN
SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE SOUTHCENTRAL
INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE OTHER
HAND....THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER NORTHWEST
CANADA SATURDAY...WITH A SEPARATE WAVE OVER THE INTERIOR PUSHING
SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY AFTERNOON. THIS
WOULD RESULT IN DRIER CONDITIONS OVER THE SOUTHCENTRAL INTERIOR
THROUGH MUCH OF THE WEEKEND WITH SHOWERY CONDITIONS DEVELOPING
SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT THE SURFACE...MODELS
ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE GULF RETREATING TO
THE SOUTH...AS LOWER PRESSURE NOSES IN FROM NORTHWESTERN CANADA
THROUGH EARLY NEXT WEEK. HOWEVER...WITH THE MODEL DISCREPANCIES IN
THE UPPER LEVELS...FORECAST CONFIDENCE REGARDING THE ABOVE
MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT...HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY...BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH...THEN WEAKEN AS
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE...LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIP INTO THE WESTERN AND CENTRAL
ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 170 172 173 174 175 176 177 178 185.
FIRE WEATHER...NONE.

&&

$$

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




000
FXAK68 PAFC 271249
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
449 AM AKDT WED MAY 27 2015

.ANALYSIS AND UPPER LEVELS...

THE MASSIVE UPPER LEVEL RIDGE CENTERED OVER THE ALCAN IS BEING
UNDERCUT BY A SMALL UPPER LOW CURRENTLY OVER SOUTHEAST AK THIS
MORNING. A LARGER UPPER LOW ENCOMPASSES MOST OF THE BERING. AT
THE SURFACE...A SLOWLY WEAKENING LOW IS OVER THE WESTERN BERING AS
ITS ASSOCIATED SHOWER PRODUCING FRONT IS OVER SW AK. HIGH
PRESSURE OVER THE GULF EXTENDS OVER MUCH OF THE MAINLAND...
INTERRUPTED ONLY BY A THERMAL TROUGH DRAPED NORTH OF THE AK RANGE
AND NOSING INTO THE COPPER RIVER BASIN.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE RIDGE OVER MAINLAND AK WILL
REBUILD TODAY. AN UPPER TROUGH WILL RIPPLE ALONG ITS WESTERN
FLANK THU AND FLATTEN THE NORTHERN EXTENT OF THE RIDGE FRI NIGHT.
THIS WILL ALLOW THE SW AK FRONT TO WEAKEN AND MOVE EAST AS AN
AREA OF MOISTURE...REACHING THE ALCAN BY FRI MORNING. THE THERMAL
TROUGH WILL EDGE ACROSS THE AK RANGE INTO THE COPPER RIVER BASIN
THIS AFTERNOON AND THEN MAKE A MORE SUBSTANTIAL INTRUSION OVER
MOST OF THE COPPER RIVER BASIN ON THU WHERE IT WILL INTERACT WITH
THE MOISTURE REMNANT OF THE SW AK FRONT. MODELS ARE ALSO IN
AGREEMENT THAT THE CURRENT BERING LOW WILL DISSIPATE TONIGHT...BUT
AN INTENSIFYING NORTH PACIFIC LOW WILL REACH THE ALEUTIANS BY THU
MORNING AND THEN CROSS INTO THE BERING. THE FORECASTS UTILIZE THE
EC IN THE WEST AND THE NAM IN THE EAST...THE LATTER HAVING PERFORMED
WELL IN PINPOINTING POSSIBLE THUNDERSTORM AREAS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
HIGH PRESSURE WILL BUILD OVER SOUTH CENTRAL ALASKA TODAY AND
THURSDAY WITH A WARMING TREND ON TAP. SOME LINGERING MOISTURE
OVER THE COPPER RIVER BASIN WILL KEEP A CHANCE OF SHOWERS FOR THAT
AREA...AND A SLIGHT RISK OF DIURNAL THUNDERSTORMS WITH SLIGHTLY
UNSTABLE CONDITIONS. AN UPPER LEVEL SHORT WAVE ASSOCIATED WITH THE
BERING LOW WILL SKIRT THE AREA TO THE WEST AND THEN NORTH ON
THURSDAY...HELPING TO KEEP THE CONDITIONS UNSTABLE IN THE COPPER
RIVER BASIN.

&&

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

A STALLED AND WEAKENING FRONTAL ZONE WILL REMAIN OVER THE
SOUTHWEST COAST THROUGH THIS EVENING BEFORE WEAKENING. MOST OF
THE RAINFALL ASSOCIATED WITH THIS WILL BE OVER THE KUSKOKWIM DELTA
AND WESTERN CAPES. INLAND LOCATIONS WILL REMAIN DRY AND WARMER
TODAY. ON THURSDAY...THE WEAKENED UPPER LEVEL LOW WILL MOVE
EAST...SPREADING SOME MID LEVEL CLOUDS AND A FEW SHOWERS ACROSS
THE LOWER KUSKOKWIM VALLEY AND BRISTOL BAY...BUT MOST LOCATIONS
WILL JUST REMAIN DRY. HIGH PRESSURE ALOFT WILL THEN SETTLE IN
THROUGH FRIDAY BEFORE ANOTHER FRONT TRACKS TOWARD THE COAST.
PATCHY OVERNIGHT FOG WILL GENERALLY REMAIN RELEGATED TO COASTAL
LOCATIONS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

A BROAD LOW OVER THE WESTERN BERING...WITH THE ASSOCIATED FRONT
OVER THE EASTERN BERING...WILL WEAKEN TODAY BEFORE A STRONG LOW
FOR THIS TIME OF YEAR MOVES INTO THE WESTERN BERING AND ALEUTIANS
TONIGHT AND THURSDAY. THE LOW IS EXPECTED TO TRACK IN THE VICINITY
OF KISKA...WITH STRONG SOUTH TO SOUTHEAST MAX GALE FORCE WINDS
IMPACTING THE WESTERN AND CENTRAL ALEUTIANS. STORM FORCE WIND
GUSTS WILL ALSO IMPACT THE REGION...WITH GUSTY WINDS EXTENDING TO
THE EASTERN ALEUTIANS AS THE LOW MOVES NORTH ON THURSDAY AND
THURSDAY NIGHT. MODERATE TO HEAVY RAIN WILL ALSO SPREAD OVER THE
BERING AS THE FRONTAL ZONE TRACKS EAST.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY...AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE...BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA...SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF. THIS WOULD ESSENTIALLY RESULT IN
SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE SOUTHCENTRAL
INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE OTHER
HAND....THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER NORTHWEST
CANADA SATURDAY...WITH A SEPARATE WAVE OVER THE INTERIOR PUSHING
SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY AFTERNOON. THIS
WOULD RESULT IN DRIER CONDITIONS OVER THE SOUTHCENTRAL INTERIOR
THROUGH MUCH OF THE WEEKEND WITH SHOWERY CONDITIONS DEVELOPING
SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT THE SURFACE...MODELS
ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE GULF RETREATING TO
THE SOUTH...AS LOWER PRESSURE NOSES IN FROM NORTHWESTERN CANADA
THROUGH EARLY NEXT WEEK. HOWEVER...WITH THE MODEL DISCREPANCIES IN
THE UPPER LEVELS...FORECAST CONFIDENCE REGARDING THE ABOVE
MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT...HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY...BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH...THEN WEAKEN AS
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE...LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIP INTO THE WESTERN AND CENTRAL
ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 170 172 173 174 175 176 177 178 185.
FIRE WEATHER...NONE.

&&

$$

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





000
FXAK68 PAFC 270022
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...
A LARGE AMPLITUDE PATTERN PERSISTS OVER ALASKA WITH A LARGE LOW
OVER THE WESTERN BERING SEA AND RIDGE THAT EXTENDS THROUGH BRITISH
COLUMBIA INTO THE BEAUFORT SEA. IN BETWEEN THE TWO LARGE FEATURES
IS AN UPPER LEVEL LOW OVER THE WESTERN GULF OF ALASKA AND A FRONT
MAKING ITS WAY TO THE WEST COAST OF ALASKA. THE UPPER LEVEL LOW
OVER THE GULF OF ALASKA IS PUSHING MOISTURE INTO SOUTH CENTRAL
ALASKA. THE AIR MASS IS A BIT UNSTABLE BUT WITH THE CLOUD COVER
CONVECTIVE INITIATION WILL BE LIMITED TO THE OUTSKIRTS OF THE
CLOUD COVER THIS AFTERNOON AND EVENING. THIS PUSHES MUCH OF THE
CONVECTION NORTH OF THE ALASKA AND WRANGELL MOUNTAIN RANGES. HIGH
PRESSURE AT THE SURFACE OVER THE GULF OF ALASKA IS BRINGING LOW
LEVEL MOISTURE TO THE GULF COAST LOCATIONS AS EVIDENT BY STRATUS
AT MANY OF THE LOCATIONS THIS MORNING. WITH THE FRONT ACROSS THE
EASTERN BERING SEA GALE FORCE WINDS AND MODERATE PRECIPITATION IS
ACCOMPANYING THE FRONT. THE FRONT IS STRETCHING AND WEAKENING
THIS EVENING AS IT RUNS AGAINST THE RIDGE OVER THE EASTERN
MAINLAND. AN UPPER LEVEL DISTURBANCE COUPLED WITH A 150 KT JET
STREAK ON THE BACK SIDE OF THE UPPER LOW IN THE BERING SEA HAS
INCREASED WINDS IN THE FAR WESTERN ALEUTIANS TODAY AND WILL WEAKEN
TONIGHT AS THE LOW CONTINUES TO WRAP UP IN THE WESTERN BERING SEA.

&&

.MODEL DISCUSSION...
DUE TO THE FACT THE ATMOSPHERE REMAINS IN A STRONG LONG WAVE
PATTERN MODEL AGREEMENT IS HIGH THROUGH THURSDAY IN THE UPPER
LEVELS AND THROUGH FRIDAY AT THE SURFACE. THEREFORE FORECAST
CONFIDENCE IS HIGH FOR THE NEXT 48 TO 72 HOURS.

THE LOW IN THE WESTERN BERING SEA WILL CONTINUE TO WRAP UP INTO
TONIGHT AND RETROGRADE TO THE KAMCHATKA PENINSULA BEFORE
DISSIPATING ON WEDNESDAY. A STRONG SHORT WAVE TROUGH COUPLED WITH
A 130 KNOT JET WILL DIVE TO THE SOUTH OF THE WESTERN BERING LOW
WEDNESDAY AND EVENTUALLY BECOME THE DOMINANT LOW WEDNESDAY NIGHT
AS IT DEEPENS INTO THE 970S MB NEAR ATTU ISLAND. THIS STRONGER LOW
BUILDS UP THE RIDGE OVER THE MAINLAND. AS THE LOW BUILDS IN THE
WESTERN BERING A FRONT WILL PUSH THROUGH TO THE CENTRAL BERING
THURSDAY NIGHT.

THE FRONT IN THE EASTERN BERING PUSHES TO THE COAST THIS
AFTERNOON/EVENING BUT WEAKENS AS IT HITS THE RIDGE TONIGHT. A
SECONDARY UPPER LEVEL DISTURBANCE MOVES AROUND THE BIG LOW IN THE
BERING SEA AND IS EXPECTED TO PUSH THE WEAKENED FRONT INLAND
THURSDAY ACROSS THE MAINLAND. THIS UPPER LEVEL FEATURE IS ENOUGH
TO SPARK CONVECTION BUT LIKELY WILL BE LIMITED TO ALONG THE
ALASKA RANGE. THE SHORT WAVE RIDGE BEHIND THE UPPER LEVEL FEATURE
KEEPS SOUTHWEST ALASKA THURSDAY AFTERNOON.

OVER SOUTH CENTRAL ANY CONVECTION...THUNDERSTORMS...WILL BE
LIMITED TO THE ALASKA RANGE AND NORTH TOWARD TOK. EXPECT SHOWERS
OVER THE COPPER BASIN WHERE THE AIR MASS IS UNSTABLE ENOUGH BUT
CLOUD COVER WILL LIMIT THE CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND EVENING. SHOWER ACTIVITY WILL DIMINISH OVERNIGHT. HIGH
PRESSURE AT THE SURFACE WILL HAVE LOW LEVEL MOISTURE PRESENT
THROUGH THURSDAY MORNING. AFTERNOON HEATING IS BREAKING THAT UP
TODAY AND WILL AGAIN TOMORROW BUT OVERNIGHT STRATUS IS EXPECTED
AGAIN TONIGHT. STRATUS IN MOST AREAS WILL BE SHORTER LIVED
TOMORROW AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA MIXING
THE AIR MASS. THIS UPPER LEVEL TROUGH WILL ALSO INITIATE SHOWERS
ALONG THE TALKEETNA MOUNTAINS AND ALASKA RANGE THURSDAY AFTERNOON.
HIGH PRESSURE BUILDS BACK FRIDAY FOR CLEAR SKIES AND WARMER
TEMPERATURES.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AS THE UPPER LEVEL LOW PUSHES OFF TO THE SOUTHEAST HIGH PRESSURE
BUILDS IN FROM THE SOUTHWEST. RAIN SHOWERS WILL CONTINUE TO
DIMINISH AS THE LOW MOVES AWAY WITH CLOUD COVER NORTH OF THE KENAI
PENINSULA ALSO STARTING TO LIGHTEN UP. UNDERNEATH THE HIGH
PRESSURE STRATUS AND FOG IS EXPECTED TO MOVE IN OVER THE WESTERN
KENAI PENINSULA TONIGHT BUT SHOULD CLEAR UP BY TOMORROW AFTERNOON.
CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THURSDAY WITH
RELATIVELY LIGHT WINDS AROUND THE SOUTHCENTRAL REGION WITH
AFTERNOON/EVENING SEA BREEZES.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A FRONTAL SYSTEM WILL REACH THE WEST COAST OF ALASKA THIS EVENING
WHERE IT WILL WEAKEN AND REMAIN STATIONARY THROUGH WEDNESDAY. AN
UPPER LEVEL TROUGH WILL SWING THE REMNANTS OF THE FRONTAL SYSTEM
INLAND IN THE FORM OF SCATTERED SHOWERS WEDNESDAY NIGHT AND
THURSDAY MORNING. A BUILDING RIDGE WILL PUSH THE SHOWERS NORTHEAST
AND OUT OF THE AREA THURSDAY AFTERNOON AND EVENING WITH DRIER AND
MORE STABLE CONDITIONS BUILDING IN THURSDAY NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE AREA OF LOW PRESSURE IN THE WESTERN BERING WILL CONTINUE TO
FILL AS IT DRIFTS NORTHWEST TONIGHT AND WEDNESDAY. AS THE PARENT
LOW PULLS FURTHER AWAY AND THE ADVANCING BERING FRONTAL SYSTEM
RUNS INTO THE LARGE BLOCKING RIDGE INLAND IT WILL STALL AND
WEAKEN ALONG THE WEST COAST AS IT IS GRADUALLY SHEARED APART.

THE NEXT RATHER POTENT LOW PRESSURE SYSTEM WILL RAPIDLY DEEPEN
WEDNESDAY AS IT APPROACHES THE ALEUTIANS FROM THE SOUTH REACHING
ITS DEEPEST POINT LATE WEDNESDAY NIGHT. CURRENT MODEL RUNS TRACK
THE CENTER OF THE LOW OVER KISKA ISLAND THURSDAY MORNING THEN LIFT
IT NORTH THROUGH THE BERING FOLLOWING A VERY SIMILAR PATH TO THE
LAST SYSTEM. ALSO LIKE THE PREVIOUS SYSTEM THIS LOOKS TO BE
ANOTHER UNSEASONABLY STRONG LOW PRESSURE SYSTEM WITH GOOD THERMAL
AND UPPER LEVEL SUPPORT. IT WILL LIKELY BRING A BROAD AREA OF
GALES WITH IT TO BOTH THE ALEUTIANS AND BERING WITH THE POTENTIAL
FOR STRONGER WINDS MIXING DOWN IN THE AREA OF COLD ADVECTION TO
THE LOWS SOUTH.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF OF ALASKA. THIS WOULD ESSENTIALLY
RESULT IN SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE
SOUTHCENTRAL INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE
OTHER HAND THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER
NORTHWEST CANADA SATURDAY WITH A SEPARATE WAVE OVER THE INTERIOR
PUSHING SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY
AFTERNOON. THIS WOULD RESULT IN DRIER CONDITIONS OVER THE
SOUTHCENTRAL INTERIOR THROUGH MUCH OF THE WEEKEND WITH SHOWERY
CONDITIONS DEVELOPING SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT
THE SURFACE MODELS ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE
GULF OF ALASKA RETREATING TO THE SOUTH AS LOWER PRESSURE NOSES IN
FROM NORTHWESTERN CANADA THROUGH EARLY NEXT WEEK. HOWEVER WITH
THE MODEL DISCREPANCIES IN THE UPPER LEVELS FORECAST CONFIDENCE
REGARDING THE ABOVE MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH THEN WEAKEN AS IT
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIPITATION INTO THE WESTERN AND
CENTRAL ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 175 176 177 180 180 413.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP





000
FXAK68 PAFC 270022
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...
A LARGE AMPLITUDE PATTERN PERSISTS OVER ALASKA WITH A LARGE LOW
OVER THE WESTERN BERING SEA AND RIDGE THAT EXTENDS THROUGH BRITISH
COLUMBIA INTO THE BEAUFORT SEA. IN BETWEEN THE TWO LARGE FEATURES
IS AN UPPER LEVEL LOW OVER THE WESTERN GULF OF ALASKA AND A FRONT
MAKING ITS WAY TO THE WEST COAST OF ALASKA. THE UPPER LEVEL LOW
OVER THE GULF OF ALASKA IS PUSHING MOISTURE INTO SOUTH CENTRAL
ALASKA. THE AIR MASS IS A BIT UNSTABLE BUT WITH THE CLOUD COVER
CONVECTIVE INITIATION WILL BE LIMITED TO THE OUTSKIRTS OF THE
CLOUD COVER THIS AFTERNOON AND EVENING. THIS PUSHES MUCH OF THE
CONVECTION NORTH OF THE ALASKA AND WRANGELL MOUNTAIN RANGES. HIGH
PRESSURE AT THE SURFACE OVER THE GULF OF ALASKA IS BRINGING LOW
LEVEL MOISTURE TO THE GULF COAST LOCATIONS AS EVIDENT BY STRATUS
AT MANY OF THE LOCATIONS THIS MORNING. WITH THE FRONT ACROSS THE
EASTERN BERING SEA GALE FORCE WINDS AND MODERATE PRECIPITATION IS
ACCOMPANYING THE FRONT. THE FRONT IS STRETCHING AND WEAKENING
THIS EVENING AS IT RUNS AGAINST THE RIDGE OVER THE EASTERN
MAINLAND. AN UPPER LEVEL DISTURBANCE COUPLED WITH A 150 KT JET
STREAK ON THE BACK SIDE OF THE UPPER LOW IN THE BERING SEA HAS
INCREASED WINDS IN THE FAR WESTERN ALEUTIANS TODAY AND WILL WEAKEN
TONIGHT AS THE LOW CONTINUES TO WRAP UP IN THE WESTERN BERING SEA.

&&

.MODEL DISCUSSION...
DUE TO THE FACT THE ATMOSPHERE REMAINS IN A STRONG LONG WAVE
PATTERN MODEL AGREEMENT IS HIGH THROUGH THURSDAY IN THE UPPER
LEVELS AND THROUGH FRIDAY AT THE SURFACE. THEREFORE FORECAST
CONFIDENCE IS HIGH FOR THE NEXT 48 TO 72 HOURS.

THE LOW IN THE WESTERN BERING SEA WILL CONTINUE TO WRAP UP INTO
TONIGHT AND RETROGRADE TO THE KAMCHATKA PENINSULA BEFORE
DISSIPATING ON WEDNESDAY. A STRONG SHORT WAVE TROUGH COUPLED WITH
A 130 KNOT JET WILL DIVE TO THE SOUTH OF THE WESTERN BERING LOW
WEDNESDAY AND EVENTUALLY BECOME THE DOMINANT LOW WEDNESDAY NIGHT
AS IT DEEPENS INTO THE 970S MB NEAR ATTU ISLAND. THIS STRONGER LOW
BUILDS UP THE RIDGE OVER THE MAINLAND. AS THE LOW BUILDS IN THE
WESTERN BERING A FRONT WILL PUSH THROUGH TO THE CENTRAL BERING
THURSDAY NIGHT.

THE FRONT IN THE EASTERN BERING PUSHES TO THE COAST THIS
AFTERNOON/EVENING BUT WEAKENS AS IT HITS THE RIDGE TONIGHT. A
SECONDARY UPPER LEVEL DISTURBANCE MOVES AROUND THE BIG LOW IN THE
BERING SEA AND IS EXPECTED TO PUSH THE WEAKENED FRONT INLAND
THURSDAY ACROSS THE MAINLAND. THIS UPPER LEVEL FEATURE IS ENOUGH
TO SPARK CONVECTION BUT LIKELY WILL BE LIMITED TO ALONG THE
ALASKA RANGE. THE SHORT WAVE RIDGE BEHIND THE UPPER LEVEL FEATURE
KEEPS SOUTHWEST ALASKA THURSDAY AFTERNOON.

OVER SOUTH CENTRAL ANY CONVECTION...THUNDERSTORMS...WILL BE
LIMITED TO THE ALASKA RANGE AND NORTH TOWARD TOK. EXPECT SHOWERS
OVER THE COPPER BASIN WHERE THE AIR MASS IS UNSTABLE ENOUGH BUT
CLOUD COVER WILL LIMIT THE CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND EVENING. SHOWER ACTIVITY WILL DIMINISH OVERNIGHT. HIGH
PRESSURE AT THE SURFACE WILL HAVE LOW LEVEL MOISTURE PRESENT
THROUGH THURSDAY MORNING. AFTERNOON HEATING IS BREAKING THAT UP
TODAY AND WILL AGAIN TOMORROW BUT OVERNIGHT STRATUS IS EXPECTED
AGAIN TONIGHT. STRATUS IN MOST AREAS WILL BE SHORTER LIVED
TOMORROW AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA MIXING
THE AIR MASS. THIS UPPER LEVEL TROUGH WILL ALSO INITIATE SHOWERS
ALONG THE TALKEETNA MOUNTAINS AND ALASKA RANGE THURSDAY AFTERNOON.
HIGH PRESSURE BUILDS BACK FRIDAY FOR CLEAR SKIES AND WARMER
TEMPERATURES.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AS THE UPPER LEVEL LOW PUSHES OFF TO THE SOUTHEAST HIGH PRESSURE
BUILDS IN FROM THE SOUTHWEST. RAIN SHOWERS WILL CONTINUE TO
DIMINISH AS THE LOW MOVES AWAY WITH CLOUD COVER NORTH OF THE KENAI
PENINSULA ALSO STARTING TO LIGHTEN UP. UNDERNEATH THE HIGH
PRESSURE STRATUS AND FOG IS EXPECTED TO MOVE IN OVER THE WESTERN
KENAI PENINSULA TONIGHT BUT SHOULD CLEAR UP BY TOMORROW AFTERNOON.
CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THURSDAY WITH
RELATIVELY LIGHT WINDS AROUND THE SOUTHCENTRAL REGION WITH
AFTERNOON/EVENING SEA BREEZES.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A FRONTAL SYSTEM WILL REACH THE WEST COAST OF ALASKA THIS EVENING
WHERE IT WILL WEAKEN AND REMAIN STATIONARY THROUGH WEDNESDAY. AN
UPPER LEVEL TROUGH WILL SWING THE REMNANTS OF THE FRONTAL SYSTEM
INLAND IN THE FORM OF SCATTERED SHOWERS WEDNESDAY NIGHT AND
THURSDAY MORNING. A BUILDING RIDGE WILL PUSH THE SHOWERS NORTHEAST
AND OUT OF THE AREA THURSDAY AFTERNOON AND EVENING WITH DRIER AND
MORE STABLE CONDITIONS BUILDING IN THURSDAY NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE AREA OF LOW PRESSURE IN THE WESTERN BERING WILL CONTINUE TO
FILL AS IT DRIFTS NORTHWEST TONIGHT AND WEDNESDAY. AS THE PARENT
LOW PULLS FURTHER AWAY AND THE ADVANCING BERING FRONTAL SYSTEM
RUNS INTO THE LARGE BLOCKING RIDGE INLAND IT WILL STALL AND
WEAKEN ALONG THE WEST COAST AS IT IS GRADUALLY SHEARED APART.

THE NEXT RATHER POTENT LOW PRESSURE SYSTEM WILL RAPIDLY DEEPEN
WEDNESDAY AS IT APPROACHES THE ALEUTIANS FROM THE SOUTH REACHING
ITS DEEPEST POINT LATE WEDNESDAY NIGHT. CURRENT MODEL RUNS TRACK
THE CENTER OF THE LOW OVER KISKA ISLAND THURSDAY MORNING THEN LIFT
IT NORTH THROUGH THE BERING FOLLOWING A VERY SIMILAR PATH TO THE
LAST SYSTEM. ALSO LIKE THE PREVIOUS SYSTEM THIS LOOKS TO BE
ANOTHER UNSEASONABLY STRONG LOW PRESSURE SYSTEM WITH GOOD THERMAL
AND UPPER LEVEL SUPPORT. IT WILL LIKELY BRING A BROAD AREA OF
GALES WITH IT TO BOTH THE ALEUTIANS AND BERING WITH THE POTENTIAL
FOR STRONGER WINDS MIXING DOWN IN THE AREA OF COLD ADVECTION TO
THE LOWS SOUTH.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF OF ALASKA. THIS WOULD ESSENTIALLY
RESULT IN SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE
SOUTHCENTRAL INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE
OTHER HAND THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER
NORTHWEST CANADA SATURDAY WITH A SEPARATE WAVE OVER THE INTERIOR
PUSHING SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY
AFTERNOON. THIS WOULD RESULT IN DRIER CONDITIONS OVER THE
SOUTHCENTRAL INTERIOR THROUGH MUCH OF THE WEEKEND WITH SHOWERY
CONDITIONS DEVELOPING SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT
THE SURFACE MODELS ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE
GULF OF ALASKA RETREATING TO THE SOUTH AS LOWER PRESSURE NOSES IN
FROM NORTHWESTERN CANADA THROUGH EARLY NEXT WEEK. HOWEVER WITH
THE MODEL DISCREPANCIES IN THE UPPER LEVELS FORECAST CONFIDENCE
REGARDING THE ABOVE MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH THEN WEAKEN AS IT
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIPITATION INTO THE WESTERN AND
CENTRAL ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 175 176 177 180 180 413.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP





000
FXAK68 PAFC 270022
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...
A LARGE AMPLITUDE PATTERN PERSISTS OVER ALASKA WITH A LARGE LOW
OVER THE WESTERN BERING SEA AND RIDGE THAT EXTENDS THROUGH BRITISH
COLUMBIA INTO THE BEAUFORT SEA. IN BETWEEN THE TWO LARGE FEATURES
IS AN UPPER LEVEL LOW OVER THE WESTERN GULF OF ALASKA AND A FRONT
MAKING ITS WAY TO THE WEST COAST OF ALASKA. THE UPPER LEVEL LOW
OVER THE GULF OF ALASKA IS PUSHING MOISTURE INTO SOUTH CENTRAL
ALASKA. THE AIR MASS IS A BIT UNSTABLE BUT WITH THE CLOUD COVER
CONVECTIVE INITIATION WILL BE LIMITED TO THE OUTSKIRTS OF THE
CLOUD COVER THIS AFTERNOON AND EVENING. THIS PUSHES MUCH OF THE
CONVECTION NORTH OF THE ALASKA AND WRANGELL MOUNTAIN RANGES. HIGH
PRESSURE AT THE SURFACE OVER THE GULF OF ALASKA IS BRINGING LOW
LEVEL MOISTURE TO THE GULF COAST LOCATIONS AS EVIDENT BY STRATUS
AT MANY OF THE LOCATIONS THIS MORNING. WITH THE FRONT ACROSS THE
EASTERN BERING SEA GALE FORCE WINDS AND MODERATE PRECIPITATION IS
ACCOMPANYING THE FRONT. THE FRONT IS STRETCHING AND WEAKENING
THIS EVENING AS IT RUNS AGAINST THE RIDGE OVER THE EASTERN
MAINLAND. AN UPPER LEVEL DISTURBANCE COUPLED WITH A 150 KT JET
STREAK ON THE BACK SIDE OF THE UPPER LOW IN THE BERING SEA HAS
INCREASED WINDS IN THE FAR WESTERN ALEUTIANS TODAY AND WILL WEAKEN
TONIGHT AS THE LOW CONTINUES TO WRAP UP IN THE WESTERN BERING SEA.

&&

.MODEL DISCUSSION...
DUE TO THE FACT THE ATMOSPHERE REMAINS IN A STRONG LONG WAVE
PATTERN MODEL AGREEMENT IS HIGH THROUGH THURSDAY IN THE UPPER
LEVELS AND THROUGH FRIDAY AT THE SURFACE. THEREFORE FORECAST
CONFIDENCE IS HIGH FOR THE NEXT 48 TO 72 HOURS.

THE LOW IN THE WESTERN BERING SEA WILL CONTINUE TO WRAP UP INTO
TONIGHT AND RETROGRADE TO THE KAMCHATKA PENINSULA BEFORE
DISSIPATING ON WEDNESDAY. A STRONG SHORT WAVE TROUGH COUPLED WITH
A 130 KNOT JET WILL DIVE TO THE SOUTH OF THE WESTERN BERING LOW
WEDNESDAY AND EVENTUALLY BECOME THE DOMINANT LOW WEDNESDAY NIGHT
AS IT DEEPENS INTO THE 970S MB NEAR ATTU ISLAND. THIS STRONGER LOW
BUILDS UP THE RIDGE OVER THE MAINLAND. AS THE LOW BUILDS IN THE
WESTERN BERING A FRONT WILL PUSH THROUGH TO THE CENTRAL BERING
THURSDAY NIGHT.

THE FRONT IN THE EASTERN BERING PUSHES TO THE COAST THIS
AFTERNOON/EVENING BUT WEAKENS AS IT HITS THE RIDGE TONIGHT. A
SECONDARY UPPER LEVEL DISTURBANCE MOVES AROUND THE BIG LOW IN THE
BERING SEA AND IS EXPECTED TO PUSH THE WEAKENED FRONT INLAND
THURSDAY ACROSS THE MAINLAND. THIS UPPER LEVEL FEATURE IS ENOUGH
TO SPARK CONVECTION BUT LIKELY WILL BE LIMITED TO ALONG THE
ALASKA RANGE. THE SHORT WAVE RIDGE BEHIND THE UPPER LEVEL FEATURE
KEEPS SOUTHWEST ALASKA THURSDAY AFTERNOON.

OVER SOUTH CENTRAL ANY CONVECTION...THUNDERSTORMS...WILL BE
LIMITED TO THE ALASKA RANGE AND NORTH TOWARD TOK. EXPECT SHOWERS
OVER THE COPPER BASIN WHERE THE AIR MASS IS UNSTABLE ENOUGH BUT
CLOUD COVER WILL LIMIT THE CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND EVENING. SHOWER ACTIVITY WILL DIMINISH OVERNIGHT. HIGH
PRESSURE AT THE SURFACE WILL HAVE LOW LEVEL MOISTURE PRESENT
THROUGH THURSDAY MORNING. AFTERNOON HEATING IS BREAKING THAT UP
TODAY AND WILL AGAIN TOMORROW BUT OVERNIGHT STRATUS IS EXPECTED
AGAIN TONIGHT. STRATUS IN MOST AREAS WILL BE SHORTER LIVED
TOMORROW AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA MIXING
THE AIR MASS. THIS UPPER LEVEL TROUGH WILL ALSO INITIATE SHOWERS
ALONG THE TALKEETNA MOUNTAINS AND ALASKA RANGE THURSDAY AFTERNOON.
HIGH PRESSURE BUILDS BACK FRIDAY FOR CLEAR SKIES AND WARMER
TEMPERATURES.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AS THE UPPER LEVEL LOW PUSHES OFF TO THE SOUTHEAST HIGH PRESSURE
BUILDS IN FROM THE SOUTHWEST. RAIN SHOWERS WILL CONTINUE TO
DIMINISH AS THE LOW MOVES AWAY WITH CLOUD COVER NORTH OF THE KENAI
PENINSULA ALSO STARTING TO LIGHTEN UP. UNDERNEATH THE HIGH
PRESSURE STRATUS AND FOG IS EXPECTED TO MOVE IN OVER THE WESTERN
KENAI PENINSULA TONIGHT BUT SHOULD CLEAR UP BY TOMORROW AFTERNOON.
CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THURSDAY WITH
RELATIVELY LIGHT WINDS AROUND THE SOUTHCENTRAL REGION WITH
AFTERNOON/EVENING SEA BREEZES.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A FRONTAL SYSTEM WILL REACH THE WEST COAST OF ALASKA THIS EVENING
WHERE IT WILL WEAKEN AND REMAIN STATIONARY THROUGH WEDNESDAY. AN
UPPER LEVEL TROUGH WILL SWING THE REMNANTS OF THE FRONTAL SYSTEM
INLAND IN THE FORM OF SCATTERED SHOWERS WEDNESDAY NIGHT AND
THURSDAY MORNING. A BUILDING RIDGE WILL PUSH THE SHOWERS NORTHEAST
AND OUT OF THE AREA THURSDAY AFTERNOON AND EVENING WITH DRIER AND
MORE STABLE CONDITIONS BUILDING IN THURSDAY NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE AREA OF LOW PRESSURE IN THE WESTERN BERING WILL CONTINUE TO
FILL AS IT DRIFTS NORTHWEST TONIGHT AND WEDNESDAY. AS THE PARENT
LOW PULLS FURTHER AWAY AND THE ADVANCING BERING FRONTAL SYSTEM
RUNS INTO THE LARGE BLOCKING RIDGE INLAND IT WILL STALL AND
WEAKEN ALONG THE WEST COAST AS IT IS GRADUALLY SHEARED APART.

THE NEXT RATHER POTENT LOW PRESSURE SYSTEM WILL RAPIDLY DEEPEN
WEDNESDAY AS IT APPROACHES THE ALEUTIANS FROM THE SOUTH REACHING
ITS DEEPEST POINT LATE WEDNESDAY NIGHT. CURRENT MODEL RUNS TRACK
THE CENTER OF THE LOW OVER KISKA ISLAND THURSDAY MORNING THEN LIFT
IT NORTH THROUGH THE BERING FOLLOWING A VERY SIMILAR PATH TO THE
LAST SYSTEM. ALSO LIKE THE PREVIOUS SYSTEM THIS LOOKS TO BE
ANOTHER UNSEASONABLY STRONG LOW PRESSURE SYSTEM WITH GOOD THERMAL
AND UPPER LEVEL SUPPORT. IT WILL LIKELY BRING A BROAD AREA OF
GALES WITH IT TO BOTH THE ALEUTIANS AND BERING WITH THE POTENTIAL
FOR STRONGER WINDS MIXING DOWN IN THE AREA OF COLD ADVECTION TO
THE LOWS SOUTH.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF OF ALASKA. THIS WOULD ESSENTIALLY
RESULT IN SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE
SOUTHCENTRAL INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE
OTHER HAND THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER
NORTHWEST CANADA SATURDAY WITH A SEPARATE WAVE OVER THE INTERIOR
PUSHING SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY
AFTERNOON. THIS WOULD RESULT IN DRIER CONDITIONS OVER THE
SOUTHCENTRAL INTERIOR THROUGH MUCH OF THE WEEKEND WITH SHOWERY
CONDITIONS DEVELOPING SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT
THE SURFACE MODELS ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE
GULF OF ALASKA RETREATING TO THE SOUTH AS LOWER PRESSURE NOSES IN
FROM NORTHWESTERN CANADA THROUGH EARLY NEXT WEEK. HOWEVER WITH
THE MODEL DISCREPANCIES IN THE UPPER LEVELS FORECAST CONFIDENCE
REGARDING THE ABOVE MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH THEN WEAKEN AS IT
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIPITATION INTO THE WESTERN AND
CENTRAL ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 175 176 177 180 180 413.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP




000
FXAK68 PAFC 270022
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...
A LARGE AMPLITUDE PATTERN PERSISTS OVER ALASKA WITH A LARGE LOW
OVER THE WESTERN BERING SEA AND RIDGE THAT EXTENDS THROUGH BRITISH
COLUMBIA INTO THE BEAUFORT SEA. IN BETWEEN THE TWO LARGE FEATURES
IS AN UPPER LEVEL LOW OVER THE WESTERN GULF OF ALASKA AND A FRONT
MAKING ITS WAY TO THE WEST COAST OF ALASKA. THE UPPER LEVEL LOW
OVER THE GULF OF ALASKA IS PUSHING MOISTURE INTO SOUTH CENTRAL
ALASKA. THE AIR MASS IS A BIT UNSTABLE BUT WITH THE CLOUD COVER
CONVECTIVE INITIATION WILL BE LIMITED TO THE OUTSKIRTS OF THE
CLOUD COVER THIS AFTERNOON AND EVENING. THIS PUSHES MUCH OF THE
CONVECTION NORTH OF THE ALASKA AND WRANGELL MOUNTAIN RANGES. HIGH
PRESSURE AT THE SURFACE OVER THE GULF OF ALASKA IS BRINGING LOW
LEVEL MOISTURE TO THE GULF COAST LOCATIONS AS EVIDENT BY STRATUS
AT MANY OF THE LOCATIONS THIS MORNING. WITH THE FRONT ACROSS THE
EASTERN BERING SEA GALE FORCE WINDS AND MODERATE PRECIPITATION IS
ACCOMPANYING THE FRONT. THE FRONT IS STRETCHING AND WEAKENING
THIS EVENING AS IT RUNS AGAINST THE RIDGE OVER THE EASTERN
MAINLAND. AN UPPER LEVEL DISTURBANCE COUPLED WITH A 150 KT JET
STREAK ON THE BACK SIDE OF THE UPPER LOW IN THE BERING SEA HAS
INCREASED WINDS IN THE FAR WESTERN ALEUTIANS TODAY AND WILL WEAKEN
TONIGHT AS THE LOW CONTINUES TO WRAP UP IN THE WESTERN BERING SEA.

&&

.MODEL DISCUSSION...
DUE TO THE FACT THE ATMOSPHERE REMAINS IN A STRONG LONG WAVE
PATTERN MODEL AGREEMENT IS HIGH THROUGH THURSDAY IN THE UPPER
LEVELS AND THROUGH FRIDAY AT THE SURFACE. THEREFORE FORECAST
CONFIDENCE IS HIGH FOR THE NEXT 48 TO 72 HOURS.

THE LOW IN THE WESTERN BERING SEA WILL CONTINUE TO WRAP UP INTO
TONIGHT AND RETROGRADE TO THE KAMCHATKA PENINSULA BEFORE
DISSIPATING ON WEDNESDAY. A STRONG SHORT WAVE TROUGH COUPLED WITH
A 130 KNOT JET WILL DIVE TO THE SOUTH OF THE WESTERN BERING LOW
WEDNESDAY AND EVENTUALLY BECOME THE DOMINANT LOW WEDNESDAY NIGHT
AS IT DEEPENS INTO THE 970S MB NEAR ATTU ISLAND. THIS STRONGER LOW
BUILDS UP THE RIDGE OVER THE MAINLAND. AS THE LOW BUILDS IN THE
WESTERN BERING A FRONT WILL PUSH THROUGH TO THE CENTRAL BERING
THURSDAY NIGHT.

THE FRONT IN THE EASTERN BERING PUSHES TO THE COAST THIS
AFTERNOON/EVENING BUT WEAKENS AS IT HITS THE RIDGE TONIGHT. A
SECONDARY UPPER LEVEL DISTURBANCE MOVES AROUND THE BIG LOW IN THE
BERING SEA AND IS EXPECTED TO PUSH THE WEAKENED FRONT INLAND
THURSDAY ACROSS THE MAINLAND. THIS UPPER LEVEL FEATURE IS ENOUGH
TO SPARK CONVECTION BUT LIKELY WILL BE LIMITED TO ALONG THE
ALASKA RANGE. THE SHORT WAVE RIDGE BEHIND THE UPPER LEVEL FEATURE
KEEPS SOUTHWEST ALASKA THURSDAY AFTERNOON.

OVER SOUTH CENTRAL ANY CONVECTION...THUNDERSTORMS...WILL BE
LIMITED TO THE ALASKA RANGE AND NORTH TOWARD TOK. EXPECT SHOWERS
OVER THE COPPER BASIN WHERE THE AIR MASS IS UNSTABLE ENOUGH BUT
CLOUD COVER WILL LIMIT THE CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND EVENING. SHOWER ACTIVITY WILL DIMINISH OVERNIGHT. HIGH
PRESSURE AT THE SURFACE WILL HAVE LOW LEVEL MOISTURE PRESENT
THROUGH THURSDAY MORNING. AFTERNOON HEATING IS BREAKING THAT UP
TODAY AND WILL AGAIN TOMORROW BUT OVERNIGHT STRATUS IS EXPECTED
AGAIN TONIGHT. STRATUS IN MOST AREAS WILL BE SHORTER LIVED
TOMORROW AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA MIXING
THE AIR MASS. THIS UPPER LEVEL TROUGH WILL ALSO INITIATE SHOWERS
ALONG THE TALKEETNA MOUNTAINS AND ALASKA RANGE THURSDAY AFTERNOON.
HIGH PRESSURE BUILDS BACK FRIDAY FOR CLEAR SKIES AND WARMER
TEMPERATURES.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AS THE UPPER LEVEL LOW PUSHES OFF TO THE SOUTHEAST HIGH PRESSURE
BUILDS IN FROM THE SOUTHWEST. RAIN SHOWERS WILL CONTINUE TO
DIMINISH AS THE LOW MOVES AWAY WITH CLOUD COVER NORTH OF THE KENAI
PENINSULA ALSO STARTING TO LIGHTEN UP. UNDERNEATH THE HIGH
PRESSURE STRATUS AND FOG IS EXPECTED TO MOVE IN OVER THE WESTERN
KENAI PENINSULA TONIGHT BUT SHOULD CLEAR UP BY TOMORROW AFTERNOON.
CONDITIONS WILL CONTINUE TO IMPROVE THROUGH THURSDAY WITH
RELATIVELY LIGHT WINDS AROUND THE SOUTHCENTRAL REGION WITH
AFTERNOON/EVENING SEA BREEZES.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A FRONTAL SYSTEM WILL REACH THE WEST COAST OF ALASKA THIS EVENING
WHERE IT WILL WEAKEN AND REMAIN STATIONARY THROUGH WEDNESDAY. AN
UPPER LEVEL TROUGH WILL SWING THE REMNANTS OF THE FRONTAL SYSTEM
INLAND IN THE FORM OF SCATTERED SHOWERS WEDNESDAY NIGHT AND
THURSDAY MORNING. A BUILDING RIDGE WILL PUSH THE SHOWERS NORTHEAST
AND OUT OF THE AREA THURSDAY AFTERNOON AND EVENING WITH DRIER AND
MORE STABLE CONDITIONS BUILDING IN THURSDAY NIGHT.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE AREA OF LOW PRESSURE IN THE WESTERN BERING WILL CONTINUE TO
FILL AS IT DRIFTS NORTHWEST TONIGHT AND WEDNESDAY. AS THE PARENT
LOW PULLS FURTHER AWAY AND THE ADVANCING BERING FRONTAL SYSTEM
RUNS INTO THE LARGE BLOCKING RIDGE INLAND IT WILL STALL AND
WEAKEN ALONG THE WEST COAST AS IT IS GRADUALLY SHEARED APART.

THE NEXT RATHER POTENT LOW PRESSURE SYSTEM WILL RAPIDLY DEEPEN
WEDNESDAY AS IT APPROACHES THE ALEUTIANS FROM THE SOUTH REACHING
ITS DEEPEST POINT LATE WEDNESDAY NIGHT. CURRENT MODEL RUNS TRACK
THE CENTER OF THE LOW OVER KISKA ISLAND THURSDAY MORNING THEN LIFT
IT NORTH THROUGH THE BERING FOLLOWING A VERY SIMILAR PATH TO THE
LAST SYSTEM. ALSO LIKE THE PREVIOUS SYSTEM THIS LOOKS TO BE
ANOTHER UNSEASONABLY STRONG LOW PRESSURE SYSTEM WITH GOOD THERMAL
AND UPPER LEVEL SUPPORT. IT WILL LIKELY BRING A BROAD AREA OF
GALES WITH IT TO BOTH THE ALEUTIANS AND BERING WITH THE POTENTIAL
FOR STRONGER WINDS MIXING DOWN IN THE AREA OF COLD ADVECTION TO
THE LOWS SOUTH.

&&

.LONG TERM FORECAST (DAYS 4 THROUGH 7)...

A PATTERN CHANGE MAY BE UNDERWAY STARTING FRIDAY AS AN UPPER
LEVEL TROUGH EXITS THE SOUTHCENTRAL MAINLAND TO THE NORTH AND
PUSHES FURTHER INTO THE INTERIOR BY THE WEEKEND. MODELS ARE IN
FAIR AGREEMENT WITH POSITIONING AND STRENGTH OF THIS FEATURE BUT
BEGIN TO STRUGGLE AS TIME PROGRESSES THROUGH THE WEEKEND. THE EC
AND CANADIAN MODELS SHOW THIS FEATURE JOIN UP WITH A TROUGH
ASSOCIATED WITH A LOW OVER NORTHERN CANADA SPLITTING THE RIDGE
INTO A CLOSED HIGH OVER THE CHUKCHI SEA AND A BROAD AREA OF HIGH
PRESSURE SOUTH OF THE GULF OF ALASKA. THIS WOULD ESSENTIALLY
RESULT IN SHOWERY CONDITIONS DEVELOPING OVER PARTS OF THE
SOUTHCENTRAL INTERIOR SATURDAY THROUGH EARLY NEXT WEEK. ON THE
OTHER HAND THE GFS SHOWS THIS ENERGY TRACK EASTWARD OVER
NORTHWEST CANADA SATURDAY WITH A SEPARATE WAVE OVER THE INTERIOR
PUSHING SOUTHWARD OVER THE SOUTHCENTRAL INTERIOR BY SUNDAY
AFTERNOON. THIS WOULD RESULT IN DRIER CONDITIONS OVER THE
SOUTHCENTRAL INTERIOR THROUGH MUCH OF THE WEEKEND WITH SHOWERY
CONDITIONS DEVELOPING SUNDAY AFTERNOON THROUGH EARLY NEXT WEEK. AT
THE SURFACE MODELS ARE IN FAIR AGREEMENT WITH THE HIGH OVER THE
GULF OF ALASKA RETREATING TO THE SOUTH AS LOWER PRESSURE NOSES IN
FROM NORTHWESTERN CANADA THROUGH EARLY NEXT WEEK. HOWEVER WITH
THE MODEL DISCREPANCIES IN THE UPPER LEVELS FORECAST CONFIDENCE
REGARDING THE ABOVE MENTIONED FEATURES REMAINS BELOW AVERAGE.

FURTHER WEST...AS THE LOW OVER THE FAR WESTERN BERING AND THE
ASSOCIATED FRONT OVER THE SOUTHWEST COAST WEAKENS FRIDAY
NIGHT HIGHER PRESSURE WILL BRIEFLY BUILD OVER THE BERING AND
ALEUTIANS. THIS WILL GIVE THE THE SOUTHWEST MAINLAND AND MUCH OF
THE BERING/ALEUTIANS A QUICK BREAK IN THE RAINY AND WINDY
CONDITIONS THROUGH SUNDAY BEFORE ANOTHER FRONTAL SYSTEM TRACKS
INTO THE WESTERN ALEUTIANS FROM THE WEST SUNDAY. WET AND WINDY
CONDITIONS WILL PICK BACK UP OVER THE WESTERN BERING/ALEUTIANS
SUNDAY AFTERNOON AS THE FRONT MOVES THROUGH THEN WEAKEN AS IT
SPREADS EASTWARD OVER THE CENTRAL ALEUTIANS INTO EARLY NEXT WEEK.
MODELS CONTINUE TO STRUGGLE WITH THE TIMING AND STRENGTH OF THIS
FEATURE LEADING TO LOWER THAN NORMAL FORECAST CONFIDENCE IN THE
ARRIVAL TIME OF THE WINDS AND PRECIPITATION INTO THE WESTERN AND
CENTRAL ALEUTIANS/BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 175 176 177 180 180 413.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...JN
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP




000
FXAK68 PAFC 261250
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
450 AM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...

THE MASSIVE UPPER LEVEL LOW THAT COVERS MOST OF AK...WESTERN
CANADA...AND THE EASTERN BERING IS SHOWING SIGNS OF WEAKNESS THIS
MORNING. A CLOSED UPPER LOW OVER KODIAK ISLAND IS IN THE PROCESS
OF SLICING THROUGH THE BASE OF THE RIDGE ON ITS WAY TO SE AK.
ANOTHER CLOSED LOW IS OVER THE WESTERN BERING. AT THE
SURFACE...HIGH PRESSURE IS OVER MOST OF MAINLAND AK...EXCEPT FOR A
THERMALLY INDUCED TROUGH OF LOW PRESSURE IN THE YUKON THAT EXTENDS
INTO AK NORTHEAST OF THE AK RANGE. THIS THERMAL LOW WAS THE FOCUS
OF THUNDERSTORM ACTIVITY YESTERDAY. ANOTHER LOW IS OVER THE
WESTERN BERING WITH AN ASSOCIATED FRONT CROSSING THE EASTERN
ALEUTIANS INTO THE AKPEN.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE UPPER LOW OVER KODIAK WILL RACE
TO SOUTHEAST AK BY WED AFTERNOON...THE THERMAL TROUGH WILL REMAIN
ALONG THE NORTHERN EDGE OF THE ALASKA RANGE...AND THE SURFACE AND
UPPER RIDGES WILL REBUILD THROUGH WED OVER THE REST OF MAINLAND
AK. IN THE WEST...THE BERING LOW WILL SPIN NORTHWEST AND DISSIPATE
LATER ON WED WHILE THE ASSOCIATED FRONT REACHES THE WESTERN ALASKA
COAST THIS AFTERNOON AND DISSIPATES TONIGHT. THE EC WAS USED IN
THE SHORT TERM OUT WEST AND A GEM/NAM BLEND WAS USED TO CAPTURE
DETAIL IN THE WIND AND MOISTURE FIELDS IN THE EAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AN UPPER LEVEL LOW WILL SLIDE EASTWARD ACROSS THE GULF TODAY AND
INTO THE PANHANDLE LATE TONIGHT. MOISTURE FROM THIS SYSTEM IS
PUSHING MOISTURE INTO THE COPPER RIVER BASIN AND NORTHERN SUSITNA
VALLEY. SHOWERS WILL DEVELOP OVER THESE AREAS TODAY AND CONTINUE
INTO TONIGHT...THEN MOVE EASTWARD LATE TONIGHT AND WEDNESDAY. SOME
MOISTURE AND A BIT OF INSTABILITY WILL LINGER OVER THE REMAINDER
OF SOUTH CENTRAL INTO THIS EVENING PRODUCING SOME SHOWERS...MAINLY
OVER THE MOUNTAINS. HIGH PRESSURE AT THE SURFACE WILL BUILD OVER
THE GULF AND SOUTH CENTRAL ALASKA FROM THE SOUTHWEST AS THE UPPER
LOW MOVES EAST BRINGING WITH IT A DRYING TREND. AROUND COOK INLET
SOME UP-INLET FLOW (FROM THE SOUTHWEST) WILL KEEP TEMPERATURES
COOL TODAY...WITH A WARMING TREND THEN DEVELOPING.

&&

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

A WEAKENING LOW MOVING INTO THE GULF OF ALASKA WILL CONTINUE TO
SUPPORT SHOWERS OVER PORTIONS OF BRISTOL BAY AND THE LOWER
KUSKOKWIM DELTA...ESPECIALLY OVER THE HIGHER TERRAIN...BUT
INCREASING STABILITY AND DRYING AIR WILL LIMIT THE COVERAGE AND
INTENSITY. THE NEXT MAJOR WEATHER FEATURE ACROSS SOUTHWEST WILL
BE A FRONT MOVING IN FROM THE BERING. THIS FEATURE WILL BRING
INCREASING SOUTHEAST WINDS...AS WELL AS RAIN TO COASTAL LOCATIONS
INTO WEDNESDAY BEFORE WEAKENING WEDNESDAY NIGHT. INTERIOR
LOCATIONS WILL GENERALLY REMAIN DRIER AND WARMER.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE BERING SEA REMAINS UNDER THE INFLUENCE OF THE PACIFIC STORM
TRACK...WITH A STOUT FRONTAL ZONE RACING ACROSS THE BERING SEA
THIS MORNING. THIS FRONT WILL MOVE FROM THE PRIBILOF ISLANDS AND
CENTRAL ALEUTIANS TO THE EASTERN ALEUTIANS AND EASTERN BERING SEA
BY THIS EVENING. GUSTY SOUTHERLY WINDS WILL MAINLY IMPACT THOSE
LOCATIONS...WITH A PERIOD OF MODERATE RAIN AS THE FRONT MOVES
THROUGH. THE FRONT WILL THEN STALL OVER THE EASTERN ALEUTIANS EAST
OF DUTCH HARBOR...WITH RAIN LASTING INTO WEDNESDAY. THE NEXT MAJOR
WEATHER IMPACT WILL BE A STRONG GALE FORCE LOW MOVING INTO THE
WESTERN BERING ON WEDNESDAY NIGHT AND THURSDAY...BRINGING RAIN AND
NEAR STORM FORCE WIND GUSTS TO PORTIONS OF THE WESTERN ALEUTIANS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE OVERALL PATTERN REMAINS UNCHANGED...WITH A PERSISTENT RIDGE
DOMINATING MUCH OF THE SOUTHERN MAINLAND AND GULF THROUGH THE END
OF THE WEEK...AND A SERIES OF NORTH PACIFIC LOWS TRACKING THROUGH
THE ALEUTIANS AND BERING SEA THROUGH EARLY NEXT WEEK. DRIER
CONDITIONS ARE EXPECTED OVER MUCH OF THE SOUTHERN MAINLAND AS THE
RIDGE BUILDS OVER THE AREA THROUGH THE WEEK. THIS IS ALSO EXPECTED
TO BRING SOME OF THE WARMEST TEMPERATURES SO FAR THIS SEASON TO
THE COPPER RIVER BASIN...MATSU VALLEY...AND PARTS OF THE SOUTHWEST
MAINLAND WITH TEMPERATURES CLIMBING INTO THE 70S. THE STRENGTH OF
THIS RIDGE WILL KEEP THE RAINY AND WINDY CONDITIONS CONFINED
MOSTLY TO THE BERING SEA AND ALEUTIANS THROUGH EARLY NEXT WEEK.
HOWEVER...MODELS ARE HINTING AT THE POTENTIAL FOR CONVECTIVE
SHOWERS TO DEVELOP OVER PARTS OF THE SOUTHCENTRAL MAINLAND LATER
IN THE WEEK...AS INSTABILITY INCREASES OVER THE AREA WITH THE
PASSING OF AN UPPER LEVEL TROUGH THURSDAY AFTERNOON/EVENING.
MODELS REMAIN IN FAIR AGREEMENT WITH THESE FEATURES/PATTERN OVER
THE SOUTHERN MAINLAND AND GULF...KEEPING FORECAST CONFIDENCE OVER
THE EASTERN DOMAIN SLIGHTLY ABOVE AVERAGE.

FURTHER WEST...THE ALEUTIANS AND BERING SEA WILL SEE LITTLE TO NO
BREAK FROM WET AND WINDY CONDITIONS THROUGH MUCH OF THE WEEK. THE
ABOVE MENTIONED NORTH PACIFIC LOW WILL STRENGTHEN AS IT TRACKS
THROUGH THE WESTERN/CENTRAL ALEUTIANS THURSDAY...BEFORE RECURVING
TO THE NORTHWEST OVER THE WESTERN BERING FRIDAY. THE ASSOCIATED
FRONTAL SYSTEM WILL BRING GUSTY WINDS AND RAIN TO THE
WESTERN/CENTRAL ALEUTIANS THURSDAY...THEN WEAKEN AS IT TRACKS
EASTWARD OVER THE ALEUTIAN CHAIN THROUGH THE END OF THE WEEK. AS
THE INITIAL FRONTAL SYSTEM DISSIPATES OVER THE EASTERN ALEUTIANS
AND ALASKA PENINSULA SUNDAY...ANOTHER FRONTAL SYSTEM BEGINS TO
TRACK OVER THE WESTERN ALEUTIANS/BERING FROM THE WEST. THIS
SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND GUSTY WINDS TO THE
WESTERN AND CENTRAL ALEUTIANS/BERING SUNDAY THROUGH MONDAY. MODELS
HAVE COME INTO BETTER AGREEMENT WITH THESE FEATURES OVER THE
WESTERN DOMAIN IN THE MOST RECENT MODEL RUNS. HOWEVER...THEY ARE
STILL STRUGGLING WITH THE FINER DETAILS IN BOTH TIMING AND
STRENGTH. THUS FORECAST CONFIDENCE HAS SLIGHTLY INCREASED OVER THE
WESTERN DOMAIN THROUGH MUCH OF THE LONG TERM...BUT STILL REMAINS
BELOW AVERAGE.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 170 179 185.
FIRE WEATHER...NONE.

&&

$$

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





000
FXAK68 PAFC 261250
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
450 AM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...

THE MASSIVE UPPER LEVEL LOW THAT COVERS MOST OF AK...WESTERN
CANADA...AND THE EASTERN BERING IS SHOWING SIGNS OF WEAKNESS THIS
MORNING. A CLOSED UPPER LOW OVER KODIAK ISLAND IS IN THE PROCESS
OF SLICING THROUGH THE BASE OF THE RIDGE ON ITS WAY TO SE AK.
ANOTHER CLOSED LOW IS OVER THE WESTERN BERING. AT THE
SURFACE...HIGH PRESSURE IS OVER MOST OF MAINLAND AK...EXCEPT FOR A
THERMALLY INDUCED TROUGH OF LOW PRESSURE IN THE YUKON THAT EXTENDS
INTO AK NORTHEAST OF THE AK RANGE. THIS THERMAL LOW WAS THE FOCUS
OF THUNDERSTORM ACTIVITY YESTERDAY. ANOTHER LOW IS OVER THE
WESTERN BERING WITH AN ASSOCIATED FRONT CROSSING THE EASTERN
ALEUTIANS INTO THE AKPEN.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE UPPER LOW OVER KODIAK WILL RACE
TO SOUTHEAST AK BY WED AFTERNOON...THE THERMAL TROUGH WILL REMAIN
ALONG THE NORTHERN EDGE OF THE ALASKA RANGE...AND THE SURFACE AND
UPPER RIDGES WILL REBUILD THROUGH WED OVER THE REST OF MAINLAND
AK. IN THE WEST...THE BERING LOW WILL SPIN NORTHWEST AND DISSIPATE
LATER ON WED WHILE THE ASSOCIATED FRONT REACHES THE WESTERN ALASKA
COAST THIS AFTERNOON AND DISSIPATES TONIGHT. THE EC WAS USED IN
THE SHORT TERM OUT WEST AND A GEM/NAM BLEND WAS USED TO CAPTURE
DETAIL IN THE WIND AND MOISTURE FIELDS IN THE EAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AN UPPER LEVEL LOW WILL SLIDE EASTWARD ACROSS THE GULF TODAY AND
INTO THE PANHANDLE LATE TONIGHT. MOISTURE FROM THIS SYSTEM IS
PUSHING MOISTURE INTO THE COPPER RIVER BASIN AND NORTHERN SUSITNA
VALLEY. SHOWERS WILL DEVELOP OVER THESE AREAS TODAY AND CONTINUE
INTO TONIGHT...THEN MOVE EASTWARD LATE TONIGHT AND WEDNESDAY. SOME
MOISTURE AND A BIT OF INSTABILITY WILL LINGER OVER THE REMAINDER
OF SOUTH CENTRAL INTO THIS EVENING PRODUCING SOME SHOWERS...MAINLY
OVER THE MOUNTAINS. HIGH PRESSURE AT THE SURFACE WILL BUILD OVER
THE GULF AND SOUTH CENTRAL ALASKA FROM THE SOUTHWEST AS THE UPPER
LOW MOVES EAST BRINGING WITH IT A DRYING TREND. AROUND COOK INLET
SOME UP-INLET FLOW (FROM THE SOUTHWEST) WILL KEEP TEMPERATURES
COOL TODAY...WITH A WARMING TREND THEN DEVELOPING.

&&

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

A WEAKENING LOW MOVING INTO THE GULF OF ALASKA WILL CONTINUE TO
SUPPORT SHOWERS OVER PORTIONS OF BRISTOL BAY AND THE LOWER
KUSKOKWIM DELTA...ESPECIALLY OVER THE HIGHER TERRAIN...BUT
INCREASING STABILITY AND DRYING AIR WILL LIMIT THE COVERAGE AND
INTENSITY. THE NEXT MAJOR WEATHER FEATURE ACROSS SOUTHWEST WILL
BE A FRONT MOVING IN FROM THE BERING. THIS FEATURE WILL BRING
INCREASING SOUTHEAST WINDS...AS WELL AS RAIN TO COASTAL LOCATIONS
INTO WEDNESDAY BEFORE WEAKENING WEDNESDAY NIGHT. INTERIOR
LOCATIONS WILL GENERALLY REMAIN DRIER AND WARMER.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE BERING SEA REMAINS UNDER THE INFLUENCE OF THE PACIFIC STORM
TRACK...WITH A STOUT FRONTAL ZONE RACING ACROSS THE BERING SEA
THIS MORNING. THIS FRONT WILL MOVE FROM THE PRIBILOF ISLANDS AND
CENTRAL ALEUTIANS TO THE EASTERN ALEUTIANS AND EASTERN BERING SEA
BY THIS EVENING. GUSTY SOUTHERLY WINDS WILL MAINLY IMPACT THOSE
LOCATIONS...WITH A PERIOD OF MODERATE RAIN AS THE FRONT MOVES
THROUGH. THE FRONT WILL THEN STALL OVER THE EASTERN ALEUTIANS EAST
OF DUTCH HARBOR...WITH RAIN LASTING INTO WEDNESDAY. THE NEXT MAJOR
WEATHER IMPACT WILL BE A STRONG GALE FORCE LOW MOVING INTO THE
WESTERN BERING ON WEDNESDAY NIGHT AND THURSDAY...BRINGING RAIN AND
NEAR STORM FORCE WIND GUSTS TO PORTIONS OF THE WESTERN ALEUTIANS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE OVERALL PATTERN REMAINS UNCHANGED...WITH A PERSISTENT RIDGE
DOMINATING MUCH OF THE SOUTHERN MAINLAND AND GULF THROUGH THE END
OF THE WEEK...AND A SERIES OF NORTH PACIFIC LOWS TRACKING THROUGH
THE ALEUTIANS AND BERING SEA THROUGH EARLY NEXT WEEK. DRIER
CONDITIONS ARE EXPECTED OVER MUCH OF THE SOUTHERN MAINLAND AS THE
RIDGE BUILDS OVER THE AREA THROUGH THE WEEK. THIS IS ALSO EXPECTED
TO BRING SOME OF THE WARMEST TEMPERATURES SO FAR THIS SEASON TO
THE COPPER RIVER BASIN...MATSU VALLEY...AND PARTS OF THE SOUTHWEST
MAINLAND WITH TEMPERATURES CLIMBING INTO THE 70S. THE STRENGTH OF
THIS RIDGE WILL KEEP THE RAINY AND WINDY CONDITIONS CONFINED
MOSTLY TO THE BERING SEA AND ALEUTIANS THROUGH EARLY NEXT WEEK.
HOWEVER...MODELS ARE HINTING AT THE POTENTIAL FOR CONVECTIVE
SHOWERS TO DEVELOP OVER PARTS OF THE SOUTHCENTRAL MAINLAND LATER
IN THE WEEK...AS INSTABILITY INCREASES OVER THE AREA WITH THE
PASSING OF AN UPPER LEVEL TROUGH THURSDAY AFTERNOON/EVENING.
MODELS REMAIN IN FAIR AGREEMENT WITH THESE FEATURES/PATTERN OVER
THE SOUTHERN MAINLAND AND GULF...KEEPING FORECAST CONFIDENCE OVER
THE EASTERN DOMAIN SLIGHTLY ABOVE AVERAGE.

FURTHER WEST...THE ALEUTIANS AND BERING SEA WILL SEE LITTLE TO NO
BREAK FROM WET AND WINDY CONDITIONS THROUGH MUCH OF THE WEEK. THE
ABOVE MENTIONED NORTH PACIFIC LOW WILL STRENGTHEN AS IT TRACKS
THROUGH THE WESTERN/CENTRAL ALEUTIANS THURSDAY...BEFORE RECURVING
TO THE NORTHWEST OVER THE WESTERN BERING FRIDAY. THE ASSOCIATED
FRONTAL SYSTEM WILL BRING GUSTY WINDS AND RAIN TO THE
WESTERN/CENTRAL ALEUTIANS THURSDAY...THEN WEAKEN AS IT TRACKS
EASTWARD OVER THE ALEUTIAN CHAIN THROUGH THE END OF THE WEEK. AS
THE INITIAL FRONTAL SYSTEM DISSIPATES OVER THE EASTERN ALEUTIANS
AND ALASKA PENINSULA SUNDAY...ANOTHER FRONTAL SYSTEM BEGINS TO
TRACK OVER THE WESTERN ALEUTIANS/BERING FROM THE WEST. THIS
SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND GUSTY WINDS TO THE
WESTERN AND CENTRAL ALEUTIANS/BERING SUNDAY THROUGH MONDAY. MODELS
HAVE COME INTO BETTER AGREEMENT WITH THESE FEATURES OVER THE
WESTERN DOMAIN IN THE MOST RECENT MODEL RUNS. HOWEVER...THEY ARE
STILL STRUGGLING WITH THE FINER DETAILS IN BOTH TIMING AND
STRENGTH. THUS FORECAST CONFIDENCE HAS SLIGHTLY INCREASED OVER THE
WESTERN DOMAIN THROUGH MUCH OF THE LONG TERM...BUT STILL REMAINS
BELOW AVERAGE.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 170 179 185.
FIRE WEATHER...NONE.

&&

$$

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





000
FXAK68 PAFC 261250
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
450 AM AKDT TUE MAY 26 2015

.ANALYSIS AND UPPER LEVELS...

THE MASSIVE UPPER LEVEL LOW THAT COVERS MOST OF AK...WESTERN
CANADA...AND THE EASTERN BERING IS SHOWING SIGNS OF WEAKNESS THIS
MORNING. A CLOSED UPPER LOW OVER KODIAK ISLAND IS IN THE PROCESS
OF SLICING THROUGH THE BASE OF THE RIDGE ON ITS WAY TO SE AK.
ANOTHER CLOSED LOW IS OVER THE WESTERN BERING. AT THE
SURFACE...HIGH PRESSURE IS OVER MOST OF MAINLAND AK...EXCEPT FOR A
THERMALLY INDUCED TROUGH OF LOW PRESSURE IN THE YUKON THAT EXTENDS
INTO AK NORTHEAST OF THE AK RANGE. THIS THERMAL LOW WAS THE FOCUS
OF THUNDERSTORM ACTIVITY YESTERDAY. ANOTHER LOW IS OVER THE
WESTERN BERING WITH AN ASSOCIATED FRONT CROSSING THE EASTERN
ALEUTIANS INTO THE AKPEN.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE UPPER LOW OVER KODIAK WILL RACE
TO SOUTHEAST AK BY WED AFTERNOON...THE THERMAL TROUGH WILL REMAIN
ALONG THE NORTHERN EDGE OF THE ALASKA RANGE...AND THE SURFACE AND
UPPER RIDGES WILL REBUILD THROUGH WED OVER THE REST OF MAINLAND
AK. IN THE WEST...THE BERING LOW WILL SPIN NORTHWEST AND DISSIPATE
LATER ON WED WHILE THE ASSOCIATED FRONT REACHES THE WESTERN ALASKA
COAST THIS AFTERNOON AND DISSIPATES TONIGHT. THE EC WAS USED IN
THE SHORT TERM OUT WEST AND A GEM/NAM BLEND WAS USED TO CAPTURE
DETAIL IN THE WIND AND MOISTURE FIELDS IN THE EAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AN UPPER LEVEL LOW WILL SLIDE EASTWARD ACROSS THE GULF TODAY AND
INTO THE PANHANDLE LATE TONIGHT. MOISTURE FROM THIS SYSTEM IS
PUSHING MOISTURE INTO THE COPPER RIVER BASIN AND NORTHERN SUSITNA
VALLEY. SHOWERS WILL DEVELOP OVER THESE AREAS TODAY AND CONTINUE
INTO TONIGHT...THEN MOVE EASTWARD LATE TONIGHT AND WEDNESDAY. SOME
MOISTURE AND A BIT OF INSTABILITY WILL LINGER OVER THE REMAINDER
OF SOUTH CENTRAL INTO THIS EVENING PRODUCING SOME SHOWERS...MAINLY
OVER THE MOUNTAINS. HIGH PRESSURE AT THE SURFACE WILL BUILD OVER
THE GULF AND SOUTH CENTRAL ALASKA FROM THE SOUTHWEST AS THE UPPER
LOW MOVES EAST BRINGING WITH IT A DRYING TREND. AROUND COOK INLET
SOME UP-INLET FLOW (FROM THE SOUTHWEST) WILL KEEP TEMPERATURES
COOL TODAY...WITH A WARMING TREND THEN DEVELOPING.

&&

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

A WEAKENING LOW MOVING INTO THE GULF OF ALASKA WILL CONTINUE TO
SUPPORT SHOWERS OVER PORTIONS OF BRISTOL BAY AND THE LOWER
KUSKOKWIM DELTA...ESPECIALLY OVER THE HIGHER TERRAIN...BUT
INCREASING STABILITY AND DRYING AIR WILL LIMIT THE COVERAGE AND
INTENSITY. THE NEXT MAJOR WEATHER FEATURE ACROSS SOUTHWEST WILL
BE A FRONT MOVING IN FROM THE BERING. THIS FEATURE WILL BRING
INCREASING SOUTHEAST WINDS...AS WELL AS RAIN TO COASTAL LOCATIONS
INTO WEDNESDAY BEFORE WEAKENING WEDNESDAY NIGHT. INTERIOR
LOCATIONS WILL GENERALLY REMAIN DRIER AND WARMER.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE BERING SEA REMAINS UNDER THE INFLUENCE OF THE PACIFIC STORM
TRACK...WITH A STOUT FRONTAL ZONE RACING ACROSS THE BERING SEA
THIS MORNING. THIS FRONT WILL MOVE FROM THE PRIBILOF ISLANDS AND
CENTRAL ALEUTIANS TO THE EASTERN ALEUTIANS AND EASTERN BERING SEA
BY THIS EVENING. GUSTY SOUTHERLY WINDS WILL MAINLY IMPACT THOSE
LOCATIONS...WITH A PERIOD OF MODERATE RAIN AS THE FRONT MOVES
THROUGH. THE FRONT WILL THEN STALL OVER THE EASTERN ALEUTIANS EAST
OF DUTCH HARBOR...WITH RAIN LASTING INTO WEDNESDAY. THE NEXT MAJOR
WEATHER IMPACT WILL BE A STRONG GALE FORCE LOW MOVING INTO THE
WESTERN BERING ON WEDNESDAY NIGHT AND THURSDAY...BRINGING RAIN AND
NEAR STORM FORCE WIND GUSTS TO PORTIONS OF THE WESTERN ALEUTIANS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE OVERALL PATTERN REMAINS UNCHANGED...WITH A PERSISTENT RIDGE
DOMINATING MUCH OF THE SOUTHERN MAINLAND AND GULF THROUGH THE END
OF THE WEEK...AND A SERIES OF NORTH PACIFIC LOWS TRACKING THROUGH
THE ALEUTIANS AND BERING SEA THROUGH EARLY NEXT WEEK. DRIER
CONDITIONS ARE EXPECTED OVER MUCH OF THE SOUTHERN MAINLAND AS THE
RIDGE BUILDS OVER THE AREA THROUGH THE WEEK. THIS IS ALSO EXPECTED
TO BRING SOME OF THE WARMEST TEMPERATURES SO FAR THIS SEASON TO
THE COPPER RIVER BASIN...MATSU VALLEY...AND PARTS OF THE SOUTHWEST
MAINLAND WITH TEMPERATURES CLIMBING INTO THE 70S. THE STRENGTH OF
THIS RIDGE WILL KEEP THE RAINY AND WINDY CONDITIONS CONFINED
MOSTLY TO THE BERING SEA AND ALEUTIANS THROUGH EARLY NEXT WEEK.
HOWEVER...MODELS ARE HINTING AT THE POTENTIAL FOR CONVECTIVE
SHOWERS TO DEVELOP OVER PARTS OF THE SOUTHCENTRAL MAINLAND LATER
IN THE WEEK...AS INSTABILITY INCREASES OVER THE AREA WITH THE
PASSING OF AN UPPER LEVEL TROUGH THURSDAY AFTERNOON/EVENING.
MODELS REMAIN IN FAIR AGREEMENT WITH THESE FEATURES/PATTERN OVER
THE SOUTHERN MAINLAND AND GULF...KEEPING FORECAST CONFIDENCE OVER
THE EASTERN DOMAIN SLIGHTLY ABOVE AVERAGE.

FURTHER WEST...THE ALEUTIANS AND BERING SEA WILL SEE LITTLE TO NO
BREAK FROM WET AND WINDY CONDITIONS THROUGH MUCH OF THE WEEK. THE
ABOVE MENTIONED NORTH PACIFIC LOW WILL STRENGTHEN AS IT TRACKS
THROUGH THE WESTERN/CENTRAL ALEUTIANS THURSDAY...BEFORE RECURVING
TO THE NORTHWEST OVER THE WESTERN BERING FRIDAY. THE ASSOCIATED
FRONTAL SYSTEM WILL BRING GUSTY WINDS AND RAIN TO THE
WESTERN/CENTRAL ALEUTIANS THURSDAY...THEN WEAKEN AS IT TRACKS
EASTWARD OVER THE ALEUTIAN CHAIN THROUGH THE END OF THE WEEK. AS
THE INITIAL FRONTAL SYSTEM DISSIPATES OVER THE EASTERN ALEUTIANS
AND ALASKA PENINSULA SUNDAY...ANOTHER FRONTAL SYSTEM BEGINS TO
TRACK OVER THE WESTERN ALEUTIANS/BERING FROM THE WEST. THIS
SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND GUSTY WINDS TO THE
WESTERN AND CENTRAL ALEUTIANS/BERING SUNDAY THROUGH MONDAY. MODELS
HAVE COME INTO BETTER AGREEMENT WITH THESE FEATURES OVER THE
WESTERN DOMAIN IN THE MOST RECENT MODEL RUNS. HOWEVER...THEY ARE
STILL STRUGGLING WITH THE FINER DETAILS IN BOTH TIMING AND
STRENGTH. THUS FORECAST CONFIDENCE HAS SLIGHTLY INCREASED OVER THE
WESTERN DOMAIN THROUGH MUCH OF THE LONG TERM...BUT STILL REMAINS
BELOW AVERAGE.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 170 179 185.
FIRE WEATHER...NONE.

&&

$$

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




000
FXAK68 PAFC 260006
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
406 PM AKDT MON MAY 25 2015

.ANALYSIS AND UPPER LEVELS...

A HIGHLY AMPLIFIED JET STREAM PATTERN CONTINUES ACROSS THE
STATE...WITH A SOUTH-SOUTHEASTERLY JET STREAK FROM THE CENTRAL
ALEUTIANS NORTH INTO FAR EASTERN RUSSIA...A NORTHWESTERLY JET
STREAK OVER THE SOUTHWEST COAST AND ALASKA PENINSULA...AND A WEAK
SOUTHERLY JET STREAK EXTENDING NORTH FROM THE WESTERN GULF INTO
SOUTHCENTRAL ALASKA. THIS PATTERN PRETTY MUCH DEFINES THE TROUGH-
RIDGE PATTERN IN THE MID-LEVELS...WITH AN UPPER LEVEL LOW
CURRENTLY CLOSING OFF AS IT MOVES FROM BRISTOL BAY INTO THE
SOUTHWEST GULF OF ALASKA. IMMEDIATELY UPSTREAM...A NARROW YET
RAPIDLY AMPLIFYING UPPER LEVEL RIDGE IS BUILDING OVER THE EASTERN
BERING ITSELF IMMEDIATELY DOWNSTREAM OF A LARGE UPPER LEVEL LOW
AND ASSOCIATED SURFACE LOW OVER THE WESTERN BERING SEA.

THE UPPER LEVEL LOW CURRENTLY CLOSING OFF NEAR KODIAK ISLAND IS
EXTREMELY ENERGETIC...WITH NUMEROUS DISTURBANCES BRINGING SHOWER
ACTIVITY TO MUCH OF SOUTHCENTRAL AND SOUTHWEST ALASKA. KING SALMON
HAS UNOFFICIALLY SET A NEW MAY RAINFALL RECORD WITH THIS MORNING`S
RAINFALL.

&&

.MODEL DISCUSSION (SHORT TERM)...
MODELS ARE IN GOOD AGREEMENT...ESPECIALLY THE EC AND GFS OUT
WEST WHERE A STRENGTHENING LOW WILL MOVE ACROSS THE WESTERN AND
CENTRAL ALEUTIANS AND INTO THE BERING SEA THURSDAY INTO FRIDAY.

BACK IN THE IMMEDIATE SHORT TERM...THE UPPER LOW CLOSING OFF AS IT
MOVES TOWARD THE SOUTHWEST GULF WILL MOVE EAST TOWARD THE NORTHERN
PANHANDLE INTO MID-WEEK BEFORE MOVING INLAND. THE RAPIDLY BUILDING
RIDGE IN THE MEANTIME WILL CONTINUE TO BUILD AS IT MOVES OVER THE
MAINLAND BY WEDNESDAY. AN UPPER LEVEL WAVE THAT PEELS OFF FROM THE
MAIN UPPER LOW OVER THE BERING WILL THEN MOVE NORTH AND EAST INTO
SOUTHWEST ALASKA AND BRING A MORE STABLE REGIME TO THAT REGION AS
IT ATTEMPTS TO MOVE OVER THE RIDGE LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AN UPPER LEVEL LOW WILL PUSH EAST ACROSS THE GULF WHICH WILL
ALLOW FOR INSTABILITY ACROSS THE SOUTHCENTRAL. THIS WILL LEAD TO
SHOWERS DEVELOPING INTO TUESDAY...PRIMARILY ALONG THE MOUNTAINS.
THERE IS ALSO THE POSSIBILITY THAT THIS COULD LEAD TO THUNDERSTORM
DEVELOPMENT TUESDAY AFTERNOON ALONG THE ALASKA RANGE AND TALKEETNA
MOUNTAINS BUT CONFIDENCE IS LOW. HIGH PRESSURE WILL THEN MOVE IN
FROM THE SOUTHWEST KEEPING SHOWER ACTIVITY PUSHED NORTH ALONG THE
ALASKA RANGE. WINDS SHOULD PRIMARILY BE LIGHT WITH THIS PATTERN
WITH THE EXCEPTION OF SEA BREEZE DEVELOPMENT IN THE AFTERNOON
THROUGH WEDNESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SHOWERS ASSOCIATED WITH THE UPPER LEVEL LOW CENTERED OVER THE BRISTOL
BAY AREA AND SEVERAL SMALL SHORTWAVES ROTATING AROUND IT WILL GRADUALLY
TAPER OFF TONIGHT THROUGH TUESDAY MORNING AS THIS FEATURE SHIFTS
EAST. A FAIRLY UNSTABLE AIR MASS WILL BRING THE POTENTIAL FOR
ISOLATED THUNDERSTORMS OVER THE LOWER KUSKOKWIM VALLEY THIS
AFTERNOON AND EVENING. UPPER LEVEL RIDGING WILL BUILD ALONG THE
COAST TUESDAY THEN SHIFT INLAND TUESDAY NIGHT AS A FRONTAL SYSTEM
ARRIVES AND STALLS ALONG THE WEST COAST.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE LARGE VERTICALLY STACKED UPPER LEVEL LOW CURRENTLY IN THE
SOUTHWESTERN BERING WILL GRADUALLY FILL AS IT LIFTS NORTH THROUGH
TUESDAY THEN CURVES WEST TUESDAY NIGHT AND WEDNESDAY. A WAVE
DEVELOPING ALONG THE ASSOCIATED FRONTAL SYSTEM STRETCHED OVER THE
CENTRAL ALEUTIANS WILL KEEP GALES GOING ALONG THE FRONTAL TONIGHT
THROUGH MIDDAY TUESDAY AS IT LIFTS NORTHEAST ACROSS THE BERING.
THE NEXT POTENTIALLY RATHER STRONG FRONTAL SYSTEM WILL APPROACH
THE WESTERN AND CENTRAL ALEUTIANS FROM THE SOUTH LATE IN THE DAY
WEDNESDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE OVERALL PATTERN REMAINS UNCHANGED...WITH A PERSISTENT RIDGE
DOMINATING MUCH OF THE SOUTHERN MAINLAND AND GULF THROUGH THE END
OF THE WEEK...AND A SERIES OF NORTH PACIFIC LOWS TRACKING THROUGH
THE ALEUTIANS AND BERING SEA THROUGH EARLY NEXT WEEK. DRIER
CONDITIONS ARE EXPECTED OVER MUCH OF THE SOUTHERN MAINLAND AS THE
RIDGE BUILDS OVER THE AREA THROUGH THE WEEK. THIS IS ALSO EXPECTED
TO BRING SOME OF THE WARMEST TEMPERATURES SO FAR THIS SUMMER TO THE
COPPER RIVER BASIN...MATSU VALLEY...AND PARTS OF THE SOUTHWEST
MAINLAND WITH TEMPERATURES CLIMBING INTO THE 70S. THE STRENGTH OF
THIS RIDGE WILL KEEP THE RAINY AND WINDY CONDITIONS CONFINED
MOSTLY TO THE BERING SEA AND ALEUTIANS THROUGH EARLY NEXT WEEK.
HOWEVER...MODELS ARE HINTING AT THE POTENTIAL FOR CONVECTIVE
SHOWERS TO DEVELOP OVER PARTS OF THE SOUTHCENTRAL MAINLAND LATER
IN THE WEEK...AS INSTABILITY INCREASES OVER THE AREA WITH THE
PASSING OF AN UPPER LEVEL TROUGH THURSDAY AFTERNOON/EVENING.
MODELS REMAIN IN FAIR AGREEMENT WITH THESE FEATURES/PATTERN OVER
THE SOUTHERN MAINLAND AND GULF...KEEPING FORECAST CONFIDENCE OVER
THE EASTERN DOMAIN SLIGHTLY ABOVE AVERAGE.

FURTHER WEST...THE ALEUTIANS AND BERING SEA WILL SEE LITTLE TO NO
BREAK FROM WET AND WINDY CONDITIONS THROUGH MUCH OF THE WEEK. THE
ABOVE MENTIONED NORTH PACIFIC LOW WILL STRENGTHEN AS IT TRACKS
THROUGH THE WESTERN/CENTRAL ALEUTIANS THURSDAY...BEFORE RECURVING
TO THE NORTHWEST OVER THE WESTERN BERING FRIDAY. THE ASSOCIATED
FRONTAL SYSTEM WILL BRING GUSTY WINDS AND RAIN TO THE
WESTERN/CENTRAL ALEUTIANS THURSDAY...THEN WEAKEN AS IT TRACKS
EASTWARD OVER THE ALEUTIAN CHAIN THROUGH THE END OF THE WEEK. AS
THE INITIAL FRONTAL SYSTEM DISSIPATES OVER THE EASTERN ALEUTIANS
AND ALASKA PENINSULA SUNDAY...ANOTHER FRONTAL SYSTEM BEGINS TO
TRACK OVER THE WESTERN ALEUTIANS/BERING FROM THE WEST. THIS
SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND GUSTY WINDS TO THE
WESTERN AND CENTRAL ALEUTIANS/BERING SUNDAY THROUGH MONDAY. MODELS
HAVE COME INTO BETTER AGREEMENT WITH THESE FEATURES OVER THE
WESTERN DOMAIN IN THE MOST RECENT MODEL RUNS. HOWEVER...THEY ARE
STILL STRUGGLING WITH THE FINER DETAILS IN BOTH TIMING AND
STRENGTH. THUS FORECAST CONFIDENCE HAS SLIGHTLY INCREASED OVER THE
WESTERN DOMAIN THROUGH MUCH OF THE LONG TERM...BUT STILL REMAINS
BELOW AVERAGE.

&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170-176 185
FIRE WEATHER...NONE.

&&
$$

SYNOPSIS AND MODEL DISCUSSION...CC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP




000
FXAK68 PAFC 260006
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
406 PM AKDT MON MAY 25 2015

.ANALYSIS AND UPPER LEVELS...

A HIGHLY AMPLIFIED JET STREAM PATTERN CONTINUES ACROSS THE
STATE...WITH A SOUTH-SOUTHEASTERLY JET STREAK FROM THE CENTRAL
ALEUTIANS NORTH INTO FAR EASTERN RUSSIA...A NORTHWESTERLY JET
STREAK OVER THE SOUTHWEST COAST AND ALASKA PENINSULA...AND A WEAK
SOUTHERLY JET STREAK EXTENDING NORTH FROM THE WESTERN GULF INTO
SOUTHCENTRAL ALASKA. THIS PATTERN PRETTY MUCH DEFINES THE TROUGH-
RIDGE PATTERN IN THE MID-LEVELS...WITH AN UPPER LEVEL LOW
CURRENTLY CLOSING OFF AS IT MOVES FROM BRISTOL BAY INTO THE
SOUTHWEST GULF OF ALASKA. IMMEDIATELY UPSTREAM...A NARROW YET
RAPIDLY AMPLIFYING UPPER LEVEL RIDGE IS BUILDING OVER THE EASTERN
BERING ITSELF IMMEDIATELY DOWNSTREAM OF A LARGE UPPER LEVEL LOW
AND ASSOCIATED SURFACE LOW OVER THE WESTERN BERING SEA.

THE UPPER LEVEL LOW CURRENTLY CLOSING OFF NEAR KODIAK ISLAND IS
EXTREMELY ENERGETIC...WITH NUMEROUS DISTURBANCES BRINGING SHOWER
ACTIVITY TO MUCH OF SOUTHCENTRAL AND SOUTHWEST ALASKA. KING SALMON
HAS UNOFFICIALLY SET A NEW MAY RAINFALL RECORD WITH THIS MORNING`S
RAINFALL.

&&

.MODEL DISCUSSION (SHORT TERM)...
MODELS ARE IN GOOD AGREEMENT...ESPECIALLY THE EC AND GFS OUT
WEST WHERE A STRENGTHENING LOW WILL MOVE ACROSS THE WESTERN AND
CENTRAL ALEUTIANS AND INTO THE BERING SEA THURSDAY INTO FRIDAY.

BACK IN THE IMMEDIATE SHORT TERM...THE UPPER LOW CLOSING OFF AS IT
MOVES TOWARD THE SOUTHWEST GULF WILL MOVE EAST TOWARD THE NORTHERN
PANHANDLE INTO MID-WEEK BEFORE MOVING INLAND. THE RAPIDLY BUILDING
RIDGE IN THE MEANTIME WILL CONTINUE TO BUILD AS IT MOVES OVER THE
MAINLAND BY WEDNESDAY. AN UPPER LEVEL WAVE THAT PEELS OFF FROM THE
MAIN UPPER LOW OVER THE BERING WILL THEN MOVE NORTH AND EAST INTO
SOUTHWEST ALASKA AND BRING A MORE STABLE REGIME TO THAT REGION AS
IT ATTEMPTS TO MOVE OVER THE RIDGE LATER IN THE WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA...
AN UPPER LEVEL LOW WILL PUSH EAST ACROSS THE GULF WHICH WILL
ALLOW FOR INSTABILITY ACROSS THE SOUTHCENTRAL. THIS WILL LEAD TO
SHOWERS DEVELOPING INTO TUESDAY...PRIMARILY ALONG THE MOUNTAINS.
THERE IS ALSO THE POSSIBILITY THAT THIS COULD LEAD TO THUNDERSTORM
DEVELOPMENT TUESDAY AFTERNOON ALONG THE ALASKA RANGE AND TALKEETNA
MOUNTAINS BUT CONFIDENCE IS LOW. HIGH PRESSURE WILL THEN MOVE IN
FROM THE SOUTHWEST KEEPING SHOWER ACTIVITY PUSHED NORTH ALONG THE
ALASKA RANGE. WINDS SHOULD PRIMARILY BE LIGHT WITH THIS PATTERN
WITH THE EXCEPTION OF SEA BREEZE DEVELOPMENT IN THE AFTERNOON
THROUGH WEDNESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SHOWERS ASSOCIATED WITH THE UPPER LEVEL LOW CENTERED OVER THE BRISTOL
BAY AREA AND SEVERAL SMALL SHORTWAVES ROTATING AROUND IT WILL GRADUALLY
TAPER OFF TONIGHT THROUGH TUESDAY MORNING AS THIS FEATURE SHIFTS
EAST. A FAIRLY UNSTABLE AIR MASS WILL BRING THE POTENTIAL FOR
ISOLATED THUNDERSTORMS OVER THE LOWER KUSKOKWIM VALLEY THIS
AFTERNOON AND EVENING. UPPER LEVEL RIDGING WILL BUILD ALONG THE
COAST TUESDAY THEN SHIFT INLAND TUESDAY NIGHT AS A FRONTAL SYSTEM
ARRIVES AND STALLS ALONG THE WEST COAST.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE LARGE VERTICALLY STACKED UPPER LEVEL LOW CURRENTLY IN THE
SOUTHWESTERN BERING WILL GRADUALLY FILL AS IT LIFTS NORTH THROUGH
TUESDAY THEN CURVES WEST TUESDAY NIGHT AND WEDNESDAY. A WAVE
DEVELOPING ALONG THE ASSOCIATED FRONTAL SYSTEM STRETCHED OVER THE
CENTRAL ALEUTIANS WILL KEEP GALES GOING ALONG THE FRONTAL TONIGHT
THROUGH MIDDAY TUESDAY AS IT LIFTS NORTHEAST ACROSS THE BERING.
THE NEXT POTENTIALLY RATHER STRONG FRONTAL SYSTEM WILL APPROACH
THE WESTERN AND CENTRAL ALEUTIANS FROM THE SOUTH LATE IN THE DAY
WEDNESDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE OVERALL PATTERN REMAINS UNCHANGED...WITH A PERSISTENT RIDGE
DOMINATING MUCH OF THE SOUTHERN MAINLAND AND GULF THROUGH THE END
OF THE WEEK...AND A SERIES OF NORTH PACIFIC LOWS TRACKING THROUGH
THE ALEUTIANS AND BERING SEA THROUGH EARLY NEXT WEEK. DRIER
CONDITIONS ARE EXPECTED OVER MUCH OF THE SOUTHERN MAINLAND AS THE
RIDGE BUILDS OVER THE AREA THROUGH THE WEEK. THIS IS ALSO EXPECTED
TO BRING SOME OF THE WARMEST TEMPERATURES SO FAR THIS SUMMER TO THE
COPPER RIVER BASIN...MATSU VALLEY...AND PARTS OF THE SOUTHWEST
MAINLAND WITH TEMPERATURES CLIMBING INTO THE 70S. THE STRENGTH OF
THIS RIDGE WILL KEEP THE RAINY AND WINDY CONDITIONS CONFINED
MOSTLY TO THE BERING SEA AND ALEUTIANS THROUGH EARLY NEXT WEEK.
HOWEVER...MODELS ARE HINTING AT THE POTENTIAL FOR CONVECTIVE
SHOWERS TO DEVELOP OVER PARTS OF THE SOUTHCENTRAL MAINLAND LATER
IN THE WEEK...AS INSTABILITY INCREASES OVER THE AREA WITH THE
PASSING OF AN UPPER LEVEL TROUGH THURSDAY AFTERNOON/EVENING.
MODELS REMAIN IN FAIR AGREEMENT WITH THESE FEATURES/PATTERN OVER
THE SOUTHERN MAINLAND AND GULF...KEEPING FORECAST CONFIDENCE OVER
THE EASTERN DOMAIN SLIGHTLY ABOVE AVERAGE.

FURTHER WEST...THE ALEUTIANS AND BERING SEA WILL SEE LITTLE TO NO
BREAK FROM WET AND WINDY CONDITIONS THROUGH MUCH OF THE WEEK. THE
ABOVE MENTIONED NORTH PACIFIC LOW WILL STRENGTHEN AS IT TRACKS
THROUGH THE WESTERN/CENTRAL ALEUTIANS THURSDAY...BEFORE RECURVING
TO THE NORTHWEST OVER THE WESTERN BERING FRIDAY. THE ASSOCIATED
FRONTAL SYSTEM WILL BRING GUSTY WINDS AND RAIN TO THE
WESTERN/CENTRAL ALEUTIANS THURSDAY...THEN WEAKEN AS IT TRACKS
EASTWARD OVER THE ALEUTIAN CHAIN THROUGH THE END OF THE WEEK. AS
THE INITIAL FRONTAL SYSTEM DISSIPATES OVER THE EASTERN ALEUTIANS
AND ALASKA PENINSULA SUNDAY...ANOTHER FRONTAL SYSTEM BEGINS TO
TRACK OVER THE WESTERN ALEUTIANS/BERING FROM THE WEST. THIS
SYSTEM WILL BRING ANOTHER ROUND OF RAIN AND GUSTY WINDS TO THE
WESTERN AND CENTRAL ALEUTIANS/BERING SUNDAY THROUGH MONDAY. MODELS
HAVE COME INTO BETTER AGREEMENT WITH THESE FEATURES OVER THE
WESTERN DOMAIN IN THE MOST RECENT MODEL RUNS. HOWEVER...THEY ARE
STILL STRUGGLING WITH THE FINER DETAILS IN BOTH TIMING AND
STRENGTH. THUS FORECAST CONFIDENCE HAS SLIGHTLY INCREASED OVER THE
WESTERN DOMAIN THROUGH MUCH OF THE LONG TERM...BUT STILL REMAINS
BELOW AVERAGE.

&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 170-176 185
FIRE WEATHER...NONE.

&&
$$

SYNOPSIS AND MODEL DISCUSSION...CC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JR
LONG TERM...TP





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