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000
FXAK68 PAFC 280028
AFDAFC

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

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

&&

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

&&

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

&&

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

&&

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

&&

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

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

&&

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

&&

$$

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



000
FXAK68 PAFC 280028
AFDAFC

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

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

&&

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

&&

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

&&

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

&&

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

&&

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

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

&&

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

&&

$$

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



  [top]

000
FXAK67 PAJK 280005
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
405 PM AKDT MON APR 27 2015

.SHORT TERM...AFTERNOON WV IMAGERY SHOWS A WEAKENING UPPER LOW
POSITIONED OVER THE GULF OF AK. SHARP TROUGH EXTENDS SSE INTO THE
NERN PAC FROM THE GULF LOW...AND IS SHOWING THE INITIAL STAGES OF
A BAROCLINIC LEAF SATELLITE SIGNATURE. THIS FEATURE WILL PROGRESS
TO HAIDA GWAII BY 12Z TUE...AND THEN LIFT NNE ACROSS THE SRN/CNTRL
PANHANDLE THROUGH TUE AFTERNOON. AS THIS TAKES PLACE...STRONG
SURFACE CYCLOGENESIS IS FORECAST TO OCCUR...WITH LOW PRESSURE
BOTTOMING OUT AT AROUND 980 MB BETWEEN 12-18Z TUE.
ECMWF...NAM...AND GEM ARE ALL FAIRLY CLOSE WITH THE MAGNITUDE AND
TRACK OF THE LOW...WHILE THE GFS WAS A SLIGHTLY FASTER OUTLIER.
UPDATED PRESSURE GRIDS REFLECT 12Z ECMWF/NAM SOLUTIONS.

NNELY WINDS WILL BE PREVALENT N OF THE LOW OVER THE CNTRL INSIDE
WATERS THROUGH MIDDAY TUE...OCCASIONALLY REACHING SMALL CRAFT
STRENGTH. MEANWHILE...INTENSE SLY PRESSURE GRADIENT WILL DEVELOP
OVER THE SRN PANHANDLE AND ADJACENT MARINE WATERS...YIELDING STRONG
WINDS FOR AKZ027-028 BY LATE MORNING...AND GALE FORCE WINDS OVER
CLARENCE STRAIT AND MARINE ZONE 41. FUTURE SHIFTS WILL NEED TO RE-
EVALUATE FOR POSSIBLE UPGRADE TO STORM FORCE IN CLARENCE
STRAIT...AND HIGH WIND WARNING FOR THE SRN PANHANDLE LAND ZONES.

AS THE UPPER DISTURBANCE AND ASSOCIATED SURFACE LOW MOVE INTO THE
NRN PANHANDLE BY LATE TUE AFTERNOON...WINDS WILL BECOME SLY OVER
MOST OF THE REGION. SMALL CRAFT WINDS WILL SPREAD NWD TO STEPHENS
PASSAGE AND POSSIBLY LYNN CANAL...THOUGH THE TIMING IS STILL
SOMEWHAT UNCERTAIN. SELY WINDS MAY BECOME GUSTY IN JUNEAU AS
WELL...AND THIS AREA TOO WILL NEED TO BE FURTHER EVALUATED FOR
STRONG WIND POTENTIAL.

PLUME OF PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE ENTRAINED INTO
THE SURFACE CYCLONE AND SPREAD N ACROSS THE SRN PANHANDLE LATE
TONIGHT. THIS MOISTURE COMBINED WITH A DEEP WARM CLOUD LAYER WILL
FAVOR LOCALLY HEAVY RAIN OCCURRING FROM KLAWOCK...KETCHIKAN...AND
HYDER NWD TO PETERSBURG. HOWEVER...SYSTEM MOTION WILL BE
FAST...THUS DURATION OF HEAVY RAIN WILL NOT BE LONG ENOUGH TO
RESULT IN HYDRO ISSUES. AFTER THE LOW PASSES TO THE N...COOLER
MIDLEVEL TEMPERATURES WILL SPREAD E INTO THE SRN PANHANDLE...WHICH
WILL AID IN DESTABILIZING THE ATMOSPHERE AND LEAD TO THE
GENERATION OF MUCAPE VALUES FROM 200-400 J/KG. THE UNSTABLE
ENVIRONMENT COMBINED WITH FORCING FOR ASCENT ASSOCIATED WITH
SEVERAL PASSING UPPER IMPULSES...AS WELL AS TERRAIN RELATED
ASCENT...WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS DURING THE
LATE AFTERNOON.

.LONG TERM...THE TIGHT SOUTHERLY PRESSURE GRADIENTS WILL SPREAD
NORTH INTO LYNN CANAL AS THE PRESSURES OVER THE CANADIAN YUKON
FALL AND THOSE ACROSS THE PANHANDLE RISE. THIS WILL EASILY RESULT
IN GALE FORCE SOUTHERLIES THROUGH LYNN CANAL AND STRONG WIND GUSTS
INTO SKAGWAY. IT MUST BE NOTED THAT MARINE MOS GUIDANCE IS LIFTING
SUSTAINED WINDS TO 45+ KT TUESDAY NIGHT. GIVEN A POST-FRONTAL STRONGLY
CONVECTIVE ENVIRONMENT, GALE SEEMS PROBABLE, AND THESE HIGHER
SUSTAINED WIND SPEEDS ARE FEASIBLE. WENT AHEAD AND INCLUDED SOME
STRONG WIND GUSTS THROUGH JUNEAU TUESDAY EVENING AS WELL, GIVEN
PRESSURE GRADIENTS OF -10 MB BETWEEN JUNEAU AND KETCHIKAN. WINDS
OVER AUKE BAY AND POSSIBLY THE JUNEAU AIRPORT MAY BRIEFLY TURN
SOUTHWEST TOMORROW EVENING. AS STATED EARLIER, TIMING IS NOT
COMPLETELY CERTAIN, AND THINGS COULD OCCUR SLIGHTLY EARLIER AS
WELL. OVER THE CENTRAL AND SOUTHERN PANHANDLE WINDS SHOULD BE
TRENDING DOWN. CONSIDERING THE CONVECTIVE REGIME, THERE WILL
LIKELY BE SOME GUSTY PERIODS ABOVE THE INDICATED SUSTAINS IN THE
ZONES.

A SHORTWAVE BEHIND THE STRONG SYSTEM LIFTING NORTH THROUGH THE
PANHANDLE TUESDAY WILL EXTEND A SLIGHT THUNDERSTORM THREAT FOR
SOUTHEASTERN GULF AND SOUTHERN PUBLIC ZONES TUESDAY NIGHT. WHILE
NAM STILL INDICATING THE POTENTIAL OF THUNDERSTORMS INTO
WEDNESDAY, HELD OFF ON MENTIONING AT THIS POINT, AS ECMWF AND GFS
BEGIN TO REDUCE INSTABILITY WITH THE BEGINNINGS OF SOME WARMER AIR
ADVECTION ALOFT FROM THE WEST.

FROM WEDNESDAY NIGHT BEYOND, THE MODELS ARE RECOGNIZING A COUPLE
OF SHORTWAVES SKIRTING EASTWARD ACROSS THE GULF OF ALASKA WITHIN A
ZONAL TRACK. ONE SHOULD ARRIVE THE EASTERN GULF ON WEDNESDAY NIGHT
WITH THE SECOND THURSDAY NIGHT/FRIDAY. AS CURRENTLY, MOST OF THE MODELS
ARE INDICATING THE MOST STABLE AIR REMAINING TO THE SOUTH, WE HAVE
LEFT SOUTHEAST WITHIN A CONVECTIVE REGIME ALL WEEK. THE FORECAST
READS AS IF THERE WILL BE NO BREAKS BETWEEN SYSTEMS, BUT
TRUTHFULLY, SHOWERS WILL BECOME SCATTERED AT TIMES BETWEEN
SYSTEMS, BUT UNCERTAINTY OVER TIMING IS STILL GREAT ENOUGH TO
DEMAND GUESSING GAMES SO A WHITEWASH IS NECESSARY.

WHILE WE ARE ON THE SUBJECT OF SHOWERS, WE SHOULD TAKE A QUICK
ASIDE TO CLARIFY WHAT WE MEAN BETWEEN ISOLATED SHOWERS, SCATTERED
SHOWERS, NUMEROUS SHOWERS, AND JUST SHOWERS. EACH DESCRIPTOR IS
ASSOCIATED WITH A PERCENT OF MEASURABLE PRECIPITATION, OR "POP"
FORECAST. ISOLATED SUGGESTS A 10 TO 20 PERCENT CHANCE OF
MEASURABLE PRECIPITATION RECEIVED AT ANY PARTICULAR SPOT, SAY,
WHERE YOU ARE. LIKEWISE, SCATTERED REFERS TO 30 TO 50 PERCENT,
AND NUMEROUS 60 TO 70 PERCENT. CONTRARY TO HOW IT MAY READ,
"NUMEROUS" SHOWERS GENERALLY INDICATES THAT SHOWER COVERAGE WILL
BE SUCH THAT THE CHANCES OF GETTING WET ARE A LITTLE LESS THAN
"SHOWERS" WITHOUT A DESCRIPTOR. SHOWERS WITHOUT A DESCRIPTOR
SUGGESTS A CONFIDENCE THAT MOST EVERYONE WILL GET WET.

WITH A WET WEAK, WE COOLED TEMPERATURES A BIT FOR CLOUDY AND
SHOWERY CONDITIONS, PERHAPS TWO OR THREE DEGREES BELOW NORMAL.
THESE SYSTEMS ARE FAIRLY WEAK AND THE GENERALLY ZONAL FLOW DOES
NOT SUGGEST GREAT QUANTITIES OF RAINFALL.

AFTER THE FRIDAY WAVE SLIDES EAST INTO CANADA, RIDGING WILL
ATTEMPT TO SET UP AHEAD OF A SHARPER TROUGH THAT DEVELOPS INTO AN
UPPER LOW AS IT ARRIVES IN THE SOUTHWEST GULF. THIS SYSTEM LOOKS
TO APPROACH THE PANHANDLE AND THEN DROP SOUTHEAST FOR EARLY NEXT
WEEK. AS THE TOURISTS FLOCK TO SOUTHEAST ALASKA COME EARLY MAY, IT
IS POSSIBLE FOR A BRIEF SPAN OF DRY WEATHER FOR THEIR STAY, AS
WELL AS A DRY BEGINNING OF THE WEEK FOR THOSE OF US WHO CALL OUR
CORNER OF THE GREAT LAND HOME.

USED NAM/EC FOR TUE NIGHT/WED. THEN BLENDED TO GEM, GFS, NAM, AND
EC TO ACCOUNT FOR MODEL SPREAD WITH WAVES COMING IN WED NIGHT
THROUGH FRI. WPC FROM LATE FRIDAY ONWARD. FORECAST CONFIDENCE GOOD
TUESDAY NIGHT/WEDNESDAY, AND FALLS TO AVERAGE WEDNESDAY NIGHT AND
BEYOND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ027.
         STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ036-041.
         SMALL CRAFT ADVISORY FOR PKZ012-013-031>035-042-043-051-052.

&&

$$

GARNER/ADKINS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU









000
FXAK67 PAJK 280005
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
405 PM AKDT MON APR 27 2015

.SHORT TERM...AFTERNOON WV IMAGERY SHOWS A WEAKENING UPPER LOW
POSITIONED OVER THE GULF OF AK. SHARP TROUGH EXTENDS SSE INTO THE
NERN PAC FROM THE GULF LOW...AND IS SHOWING THE INITIAL STAGES OF
A BAROCLINIC LEAF SATELLITE SIGNATURE. THIS FEATURE WILL PROGRESS
TO HAIDA GWAII BY 12Z TUE...AND THEN LIFT NNE ACROSS THE SRN/CNTRL
PANHANDLE THROUGH TUE AFTERNOON. AS THIS TAKES PLACE...STRONG
SURFACE CYCLOGENESIS IS FORECAST TO OCCUR...WITH LOW PRESSURE
BOTTOMING OUT AT AROUND 980 MB BETWEEN 12-18Z TUE.
ECMWF...NAM...AND GEM ARE ALL FAIRLY CLOSE WITH THE MAGNITUDE AND
TRACK OF THE LOW...WHILE THE GFS WAS A SLIGHTLY FASTER OUTLIER.
UPDATED PRESSURE GRIDS REFLECT 12Z ECMWF/NAM SOLUTIONS.

NNELY WINDS WILL BE PREVALENT N OF THE LOW OVER THE CNTRL INSIDE
WATERS THROUGH MIDDAY TUE...OCCASIONALLY REACHING SMALL CRAFT
STRENGTH. MEANWHILE...INTENSE SLY PRESSURE GRADIENT WILL DEVELOP
OVER THE SRN PANHANDLE AND ADJACENT MARINE WATERS...YIELDING STRONG
WINDS FOR AKZ027-028 BY LATE MORNING...AND GALE FORCE WINDS OVER
CLARENCE STRAIT AND MARINE ZONE 41. FUTURE SHIFTS WILL NEED TO RE-
EVALUATE FOR POSSIBLE UPGRADE TO STORM FORCE IN CLARENCE
STRAIT...AND HIGH WIND WARNING FOR THE SRN PANHANDLE LAND ZONES.

AS THE UPPER DISTURBANCE AND ASSOCIATED SURFACE LOW MOVE INTO THE
NRN PANHANDLE BY LATE TUE AFTERNOON...WINDS WILL BECOME SLY OVER
MOST OF THE REGION. SMALL CRAFT WINDS WILL SPREAD NWD TO STEPHENS
PASSAGE AND POSSIBLY LYNN CANAL...THOUGH THE TIMING IS STILL
SOMEWHAT UNCERTAIN. SELY WINDS MAY BECOME GUSTY IN JUNEAU AS
WELL...AND THIS AREA TOO WILL NEED TO BE FURTHER EVALUATED FOR
STRONG WIND POTENTIAL.

PLUME OF PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE ENTRAINED INTO
THE SURFACE CYCLONE AND SPREAD N ACROSS THE SRN PANHANDLE LATE
TONIGHT. THIS MOISTURE COMBINED WITH A DEEP WARM CLOUD LAYER WILL
FAVOR LOCALLY HEAVY RAIN OCCURRING FROM KLAWOCK...KETCHIKAN...AND
HYDER NWD TO PETERSBURG. HOWEVER...SYSTEM MOTION WILL BE
FAST...THUS DURATION OF HEAVY RAIN WILL NOT BE LONG ENOUGH TO
RESULT IN HYDRO ISSUES. AFTER THE LOW PASSES TO THE N...COOLER
MIDLEVEL TEMPERATURES WILL SPREAD E INTO THE SRN PANHANDLE...WHICH
WILL AID IN DESTABILIZING THE ATMOSPHERE AND LEAD TO THE
GENERATION OF MUCAPE VALUES FROM 200-400 J/KG. THE UNSTABLE
ENVIRONMENT COMBINED WITH FORCING FOR ASCENT ASSOCIATED WITH
SEVERAL PASSING UPPER IMPULSES...AS WELL AS TERRAIN RELATED
ASCENT...WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS DURING THE
LATE AFTERNOON.

.LONG TERM...THE TIGHT SOUTHERLY PRESSURE GRADIENTS WILL SPREAD
NORTH INTO LYNN CANAL AS THE PRESSURES OVER THE CANADIAN YUKON
FALL AND THOSE ACROSS THE PANHANDLE RISE. THIS WILL EASILY RESULT
IN GALE FORCE SOUTHERLIES THROUGH LYNN CANAL AND STRONG WIND GUSTS
INTO SKAGWAY. IT MUST BE NOTED THAT MARINE MOS GUIDANCE IS LIFTING
SUSTAINED WINDS TO 45+ KT TUESDAY NIGHT. GIVEN A POST-FRONTAL STRONGLY
CONVECTIVE ENVIRONMENT, GALE SEEMS PROBABLE, AND THESE HIGHER
SUSTAINED WIND SPEEDS ARE FEASIBLE. WENT AHEAD AND INCLUDED SOME
STRONG WIND GUSTS THROUGH JUNEAU TUESDAY EVENING AS WELL, GIVEN
PRESSURE GRADIENTS OF -10 MB BETWEEN JUNEAU AND KETCHIKAN. WINDS
OVER AUKE BAY AND POSSIBLY THE JUNEAU AIRPORT MAY BRIEFLY TURN
SOUTHWEST TOMORROW EVENING. AS STATED EARLIER, TIMING IS NOT
COMPLETELY CERTAIN, AND THINGS COULD OCCUR SLIGHTLY EARLIER AS
WELL. OVER THE CENTRAL AND SOUTHERN PANHANDLE WINDS SHOULD BE
TRENDING DOWN. CONSIDERING THE CONVECTIVE REGIME, THERE WILL
LIKELY BE SOME GUSTY PERIODS ABOVE THE INDICATED SUSTAINS IN THE
ZONES.

A SHORTWAVE BEHIND THE STRONG SYSTEM LIFTING NORTH THROUGH THE
PANHANDLE TUESDAY WILL EXTEND A SLIGHT THUNDERSTORM THREAT FOR
SOUTHEASTERN GULF AND SOUTHERN PUBLIC ZONES TUESDAY NIGHT. WHILE
NAM STILL INDICATING THE POTENTIAL OF THUNDERSTORMS INTO
WEDNESDAY, HELD OFF ON MENTIONING AT THIS POINT, AS ECMWF AND GFS
BEGIN TO REDUCE INSTABILITY WITH THE BEGINNINGS OF SOME WARMER AIR
ADVECTION ALOFT FROM THE WEST.

FROM WEDNESDAY NIGHT BEYOND, THE MODELS ARE RECOGNIZING A COUPLE
OF SHORTWAVES SKIRTING EASTWARD ACROSS THE GULF OF ALASKA WITHIN A
ZONAL TRACK. ONE SHOULD ARRIVE THE EASTERN GULF ON WEDNESDAY NIGHT
WITH THE SECOND THURSDAY NIGHT/FRIDAY. AS CURRENTLY, MOST OF THE MODELS
ARE INDICATING THE MOST STABLE AIR REMAINING TO THE SOUTH, WE HAVE
LEFT SOUTHEAST WITHIN A CONVECTIVE REGIME ALL WEEK. THE FORECAST
READS AS IF THERE WILL BE NO BREAKS BETWEEN SYSTEMS, BUT
TRUTHFULLY, SHOWERS WILL BECOME SCATTERED AT TIMES BETWEEN
SYSTEMS, BUT UNCERTAINTY OVER TIMING IS STILL GREAT ENOUGH TO
DEMAND GUESSING GAMES SO A WHITEWASH IS NECESSARY.

WHILE WE ARE ON THE SUBJECT OF SHOWERS, WE SHOULD TAKE A QUICK
ASIDE TO CLARIFY WHAT WE MEAN BETWEEN ISOLATED SHOWERS, SCATTERED
SHOWERS, NUMEROUS SHOWERS, AND JUST SHOWERS. EACH DESCRIPTOR IS
ASSOCIATED WITH A PERCENT OF MEASURABLE PRECIPITATION, OR "POP"
FORECAST. ISOLATED SUGGESTS A 10 TO 20 PERCENT CHANCE OF
MEASURABLE PRECIPITATION RECEIVED AT ANY PARTICULAR SPOT, SAY,
WHERE YOU ARE. LIKEWISE, SCATTERED REFERS TO 30 TO 50 PERCENT,
AND NUMEROUS 60 TO 70 PERCENT. CONTRARY TO HOW IT MAY READ,
"NUMEROUS" SHOWERS GENERALLY INDICATES THAT SHOWER COVERAGE WILL
BE SUCH THAT THE CHANCES OF GETTING WET ARE A LITTLE LESS THAN
"SHOWERS" WITHOUT A DESCRIPTOR. SHOWERS WITHOUT A DESCRIPTOR
SUGGESTS A CONFIDENCE THAT MOST EVERYONE WILL GET WET.

WITH A WET WEAK, WE COOLED TEMPERATURES A BIT FOR CLOUDY AND
SHOWERY CONDITIONS, PERHAPS TWO OR THREE DEGREES BELOW NORMAL.
THESE SYSTEMS ARE FAIRLY WEAK AND THE GENERALLY ZONAL FLOW DOES
NOT SUGGEST GREAT QUANTITIES OF RAINFALL.

AFTER THE FRIDAY WAVE SLIDES EAST INTO CANADA, RIDGING WILL
ATTEMPT TO SET UP AHEAD OF A SHARPER TROUGH THAT DEVELOPS INTO AN
UPPER LOW AS IT ARRIVES IN THE SOUTHWEST GULF. THIS SYSTEM LOOKS
TO APPROACH THE PANHANDLE AND THEN DROP SOUTHEAST FOR EARLY NEXT
WEEK. AS THE TOURISTS FLOCK TO SOUTHEAST ALASKA COME EARLY MAY, IT
IS POSSIBLE FOR A BRIEF SPAN OF DRY WEATHER FOR THEIR STAY, AS
WELL AS A DRY BEGINNING OF THE WEEK FOR THOSE OF US WHO CALL OUR
CORNER OF THE GREAT LAND HOME.

USED NAM/EC FOR TUE NIGHT/WED. THEN BLENDED TO GEM, GFS, NAM, AND
EC TO ACCOUNT FOR MODEL SPREAD WITH WAVES COMING IN WED NIGHT
THROUGH FRI. WPC FROM LATE FRIDAY ONWARD. FORECAST CONFIDENCE GOOD
TUESDAY NIGHT/WEDNESDAY, AND FALLS TO AVERAGE WEDNESDAY NIGHT AND
BEYOND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ027.
         STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ036-041.
         SMALL CRAFT ADVISORY FOR PKZ012-013-031>035-042-043-051-052.

&&

$$

GARNER/ADKINS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU









000
FXAK67 PAJK 280005
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
405 PM AKDT MON APR 27 2015

.SHORT TERM...AFTERNOON WV IMAGERY SHOWS A WEAKENING UPPER LOW
POSITIONED OVER THE GULF OF AK. SHARP TROUGH EXTENDS SSE INTO THE
NERN PAC FROM THE GULF LOW...AND IS SHOWING THE INITIAL STAGES OF
A BAROCLINIC LEAF SATELLITE SIGNATURE. THIS FEATURE WILL PROGRESS
TO HAIDA GWAII BY 12Z TUE...AND THEN LIFT NNE ACROSS THE SRN/CNTRL
PANHANDLE THROUGH TUE AFTERNOON. AS THIS TAKES PLACE...STRONG
SURFACE CYCLOGENESIS IS FORECAST TO OCCUR...WITH LOW PRESSURE
BOTTOMING OUT AT AROUND 980 MB BETWEEN 12-18Z TUE.
ECMWF...NAM...AND GEM ARE ALL FAIRLY CLOSE WITH THE MAGNITUDE AND
TRACK OF THE LOW...WHILE THE GFS WAS A SLIGHTLY FASTER OUTLIER.
UPDATED PRESSURE GRIDS REFLECT 12Z ECMWF/NAM SOLUTIONS.

NNELY WINDS WILL BE PREVALENT N OF THE LOW OVER THE CNTRL INSIDE
WATERS THROUGH MIDDAY TUE...OCCASIONALLY REACHING SMALL CRAFT
STRENGTH. MEANWHILE...INTENSE SLY PRESSURE GRADIENT WILL DEVELOP
OVER THE SRN PANHANDLE AND ADJACENT MARINE WATERS...YIELDING STRONG
WINDS FOR AKZ027-028 BY LATE MORNING...AND GALE FORCE WINDS OVER
CLARENCE STRAIT AND MARINE ZONE 41. FUTURE SHIFTS WILL NEED TO RE-
EVALUATE FOR POSSIBLE UPGRADE TO STORM FORCE IN CLARENCE
STRAIT...AND HIGH WIND WARNING FOR THE SRN PANHANDLE LAND ZONES.

AS THE UPPER DISTURBANCE AND ASSOCIATED SURFACE LOW MOVE INTO THE
NRN PANHANDLE BY LATE TUE AFTERNOON...WINDS WILL BECOME SLY OVER
MOST OF THE REGION. SMALL CRAFT WINDS WILL SPREAD NWD TO STEPHENS
PASSAGE AND POSSIBLY LYNN CANAL...THOUGH THE TIMING IS STILL
SOMEWHAT UNCERTAIN. SELY WINDS MAY BECOME GUSTY IN JUNEAU AS
WELL...AND THIS AREA TOO WILL NEED TO BE FURTHER EVALUATED FOR
STRONG WIND POTENTIAL.

PLUME OF PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE ENTRAINED INTO
THE SURFACE CYCLONE AND SPREAD N ACROSS THE SRN PANHANDLE LATE
TONIGHT. THIS MOISTURE COMBINED WITH A DEEP WARM CLOUD LAYER WILL
FAVOR LOCALLY HEAVY RAIN OCCURRING FROM KLAWOCK...KETCHIKAN...AND
HYDER NWD TO PETERSBURG. HOWEVER...SYSTEM MOTION WILL BE
FAST...THUS DURATION OF HEAVY RAIN WILL NOT BE LONG ENOUGH TO
RESULT IN HYDRO ISSUES. AFTER THE LOW PASSES TO THE N...COOLER
MIDLEVEL TEMPERATURES WILL SPREAD E INTO THE SRN PANHANDLE...WHICH
WILL AID IN DESTABILIZING THE ATMOSPHERE AND LEAD TO THE
GENERATION OF MUCAPE VALUES FROM 200-400 J/KG. THE UNSTABLE
ENVIRONMENT COMBINED WITH FORCING FOR ASCENT ASSOCIATED WITH
SEVERAL PASSING UPPER IMPULSES...AS WELL AS TERRAIN RELATED
ASCENT...WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS DURING THE
LATE AFTERNOON.

.LONG TERM...THE TIGHT SOUTHERLY PRESSURE GRADIENTS WILL SPREAD
NORTH INTO LYNN CANAL AS THE PRESSURES OVER THE CANADIAN YUKON
FALL AND THOSE ACROSS THE PANHANDLE RISE. THIS WILL EASILY RESULT
IN GALE FORCE SOUTHERLIES THROUGH LYNN CANAL AND STRONG WIND GUSTS
INTO SKAGWAY. IT MUST BE NOTED THAT MARINE MOS GUIDANCE IS LIFTING
SUSTAINED WINDS TO 45+ KT TUESDAY NIGHT. GIVEN A POST-FRONTAL STRONGLY
CONVECTIVE ENVIRONMENT, GALE SEEMS PROBABLE, AND THESE HIGHER
SUSTAINED WIND SPEEDS ARE FEASIBLE. WENT AHEAD AND INCLUDED SOME
STRONG WIND GUSTS THROUGH JUNEAU TUESDAY EVENING AS WELL, GIVEN
PRESSURE GRADIENTS OF -10 MB BETWEEN JUNEAU AND KETCHIKAN. WINDS
OVER AUKE BAY AND POSSIBLY THE JUNEAU AIRPORT MAY BRIEFLY TURN
SOUTHWEST TOMORROW EVENING. AS STATED EARLIER, TIMING IS NOT
COMPLETELY CERTAIN, AND THINGS COULD OCCUR SLIGHTLY EARLIER AS
WELL. OVER THE CENTRAL AND SOUTHERN PANHANDLE WINDS SHOULD BE
TRENDING DOWN. CONSIDERING THE CONVECTIVE REGIME, THERE WILL
LIKELY BE SOME GUSTY PERIODS ABOVE THE INDICATED SUSTAINS IN THE
ZONES.

A SHORTWAVE BEHIND THE STRONG SYSTEM LIFTING NORTH THROUGH THE
PANHANDLE TUESDAY WILL EXTEND A SLIGHT THUNDERSTORM THREAT FOR
SOUTHEASTERN GULF AND SOUTHERN PUBLIC ZONES TUESDAY NIGHT. WHILE
NAM STILL INDICATING THE POTENTIAL OF THUNDERSTORMS INTO
WEDNESDAY, HELD OFF ON MENTIONING AT THIS POINT, AS ECMWF AND GFS
BEGIN TO REDUCE INSTABILITY WITH THE BEGINNINGS OF SOME WARMER AIR
ADVECTION ALOFT FROM THE WEST.

FROM WEDNESDAY NIGHT BEYOND, THE MODELS ARE RECOGNIZING A COUPLE
OF SHORTWAVES SKIRTING EASTWARD ACROSS THE GULF OF ALASKA WITHIN A
ZONAL TRACK. ONE SHOULD ARRIVE THE EASTERN GULF ON WEDNESDAY NIGHT
WITH THE SECOND THURSDAY NIGHT/FRIDAY. AS CURRENTLY, MOST OF THE MODELS
ARE INDICATING THE MOST STABLE AIR REMAINING TO THE SOUTH, WE HAVE
LEFT SOUTHEAST WITHIN A CONVECTIVE REGIME ALL WEEK. THE FORECAST
READS AS IF THERE WILL BE NO BREAKS BETWEEN SYSTEMS, BUT
TRUTHFULLY, SHOWERS WILL BECOME SCATTERED AT TIMES BETWEEN
SYSTEMS, BUT UNCERTAINTY OVER TIMING IS STILL GREAT ENOUGH TO
DEMAND GUESSING GAMES SO A WHITEWASH IS NECESSARY.

WHILE WE ARE ON THE SUBJECT OF SHOWERS, WE SHOULD TAKE A QUICK
ASIDE TO CLARIFY WHAT WE MEAN BETWEEN ISOLATED SHOWERS, SCATTERED
SHOWERS, NUMEROUS SHOWERS, AND JUST SHOWERS. EACH DESCRIPTOR IS
ASSOCIATED WITH A PERCENT OF MEASURABLE PRECIPITATION, OR "POP"
FORECAST. ISOLATED SUGGESTS A 10 TO 20 PERCENT CHANCE OF
MEASURABLE PRECIPITATION RECEIVED AT ANY PARTICULAR SPOT, SAY,
WHERE YOU ARE. LIKEWISE, SCATTERED REFERS TO 30 TO 50 PERCENT,
AND NUMEROUS 60 TO 70 PERCENT. CONTRARY TO HOW IT MAY READ,
"NUMEROUS" SHOWERS GENERALLY INDICATES THAT SHOWER COVERAGE WILL
BE SUCH THAT THE CHANCES OF GETTING WET ARE A LITTLE LESS THAN
"SHOWERS" WITHOUT A DESCRIPTOR. SHOWERS WITHOUT A DESCRIPTOR
SUGGESTS A CONFIDENCE THAT MOST EVERYONE WILL GET WET.

WITH A WET WEAK, WE COOLED TEMPERATURES A BIT FOR CLOUDY AND
SHOWERY CONDITIONS, PERHAPS TWO OR THREE DEGREES BELOW NORMAL.
THESE SYSTEMS ARE FAIRLY WEAK AND THE GENERALLY ZONAL FLOW DOES
NOT SUGGEST GREAT QUANTITIES OF RAINFALL.

AFTER THE FRIDAY WAVE SLIDES EAST INTO CANADA, RIDGING WILL
ATTEMPT TO SET UP AHEAD OF A SHARPER TROUGH THAT DEVELOPS INTO AN
UPPER LOW AS IT ARRIVES IN THE SOUTHWEST GULF. THIS SYSTEM LOOKS
TO APPROACH THE PANHANDLE AND THEN DROP SOUTHEAST FOR EARLY NEXT
WEEK. AS THE TOURISTS FLOCK TO SOUTHEAST ALASKA COME EARLY MAY, IT
IS POSSIBLE FOR A BRIEF SPAN OF DRY WEATHER FOR THEIR STAY, AS
WELL AS A DRY BEGINNING OF THE WEEK FOR THOSE OF US WHO CALL OUR
CORNER OF THE GREAT LAND HOME.

USED NAM/EC FOR TUE NIGHT/WED. THEN BLENDED TO GEM, GFS, NAM, AND
EC TO ACCOUNT FOR MODEL SPREAD WITH WAVES COMING IN WED NIGHT
THROUGH FRI. WPC FROM LATE FRIDAY ONWARD. FORECAST CONFIDENCE GOOD
TUESDAY NIGHT/WEDNESDAY, AND FALLS TO AVERAGE WEDNESDAY NIGHT AND
BEYOND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ027.
         STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ036-041.
         SMALL CRAFT ADVISORY FOR PKZ012-013-031>035-042-043-051-052.

&&

$$

GARNER/ADKINS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU









000
FXAK67 PAJK 280005
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
405 PM AKDT MON APR 27 2015

.SHORT TERM...AFTERNOON WV IMAGERY SHOWS A WEAKENING UPPER LOW
POSITIONED OVER THE GULF OF AK. SHARP TROUGH EXTENDS SSE INTO THE
NERN PAC FROM THE GULF LOW...AND IS SHOWING THE INITIAL STAGES OF
A BAROCLINIC LEAF SATELLITE SIGNATURE. THIS FEATURE WILL PROGRESS
TO HAIDA GWAII BY 12Z TUE...AND THEN LIFT NNE ACROSS THE SRN/CNTRL
PANHANDLE THROUGH TUE AFTERNOON. AS THIS TAKES PLACE...STRONG
SURFACE CYCLOGENESIS IS FORECAST TO OCCUR...WITH LOW PRESSURE
BOTTOMING OUT AT AROUND 980 MB BETWEEN 12-18Z TUE.
ECMWF...NAM...AND GEM ARE ALL FAIRLY CLOSE WITH THE MAGNITUDE AND
TRACK OF THE LOW...WHILE THE GFS WAS A SLIGHTLY FASTER OUTLIER.
UPDATED PRESSURE GRIDS REFLECT 12Z ECMWF/NAM SOLUTIONS.

NNELY WINDS WILL BE PREVALENT N OF THE LOW OVER THE CNTRL INSIDE
WATERS THROUGH MIDDAY TUE...OCCASIONALLY REACHING SMALL CRAFT
STRENGTH. MEANWHILE...INTENSE SLY PRESSURE GRADIENT WILL DEVELOP
OVER THE SRN PANHANDLE AND ADJACENT MARINE WATERS...YIELDING STRONG
WINDS FOR AKZ027-028 BY LATE MORNING...AND GALE FORCE WINDS OVER
CLARENCE STRAIT AND MARINE ZONE 41. FUTURE SHIFTS WILL NEED TO RE-
EVALUATE FOR POSSIBLE UPGRADE TO STORM FORCE IN CLARENCE
STRAIT...AND HIGH WIND WARNING FOR THE SRN PANHANDLE LAND ZONES.

AS THE UPPER DISTURBANCE AND ASSOCIATED SURFACE LOW MOVE INTO THE
NRN PANHANDLE BY LATE TUE AFTERNOON...WINDS WILL BECOME SLY OVER
MOST OF THE REGION. SMALL CRAFT WINDS WILL SPREAD NWD TO STEPHENS
PASSAGE AND POSSIBLY LYNN CANAL...THOUGH THE TIMING IS STILL
SOMEWHAT UNCERTAIN. SELY WINDS MAY BECOME GUSTY IN JUNEAU AS
WELL...AND THIS AREA TOO WILL NEED TO BE FURTHER EVALUATED FOR
STRONG WIND POTENTIAL.

PLUME OF PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE ENTRAINED INTO
THE SURFACE CYCLONE AND SPREAD N ACROSS THE SRN PANHANDLE LATE
TONIGHT. THIS MOISTURE COMBINED WITH A DEEP WARM CLOUD LAYER WILL
FAVOR LOCALLY HEAVY RAIN OCCURRING FROM KLAWOCK...KETCHIKAN...AND
HYDER NWD TO PETERSBURG. HOWEVER...SYSTEM MOTION WILL BE
FAST...THUS DURATION OF HEAVY RAIN WILL NOT BE LONG ENOUGH TO
RESULT IN HYDRO ISSUES. AFTER THE LOW PASSES TO THE N...COOLER
MIDLEVEL TEMPERATURES WILL SPREAD E INTO THE SRN PANHANDLE...WHICH
WILL AID IN DESTABILIZING THE ATMOSPHERE AND LEAD TO THE
GENERATION OF MUCAPE VALUES FROM 200-400 J/KG. THE UNSTABLE
ENVIRONMENT COMBINED WITH FORCING FOR ASCENT ASSOCIATED WITH
SEVERAL PASSING UPPER IMPULSES...AS WELL AS TERRAIN RELATED
ASCENT...WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS DURING THE
LATE AFTERNOON.

.LONG TERM...THE TIGHT SOUTHERLY PRESSURE GRADIENTS WILL SPREAD
NORTH INTO LYNN CANAL AS THE PRESSURES OVER THE CANADIAN YUKON
FALL AND THOSE ACROSS THE PANHANDLE RISE. THIS WILL EASILY RESULT
IN GALE FORCE SOUTHERLIES THROUGH LYNN CANAL AND STRONG WIND GUSTS
INTO SKAGWAY. IT MUST BE NOTED THAT MARINE MOS GUIDANCE IS LIFTING
SUSTAINED WINDS TO 45+ KT TUESDAY NIGHT. GIVEN A POST-FRONTAL STRONGLY
CONVECTIVE ENVIRONMENT, GALE SEEMS PROBABLE, AND THESE HIGHER
SUSTAINED WIND SPEEDS ARE FEASIBLE. WENT AHEAD AND INCLUDED SOME
STRONG WIND GUSTS THROUGH JUNEAU TUESDAY EVENING AS WELL, GIVEN
PRESSURE GRADIENTS OF -10 MB BETWEEN JUNEAU AND KETCHIKAN. WINDS
OVER AUKE BAY AND POSSIBLY THE JUNEAU AIRPORT MAY BRIEFLY TURN
SOUTHWEST TOMORROW EVENING. AS STATED EARLIER, TIMING IS NOT
COMPLETELY CERTAIN, AND THINGS COULD OCCUR SLIGHTLY EARLIER AS
WELL. OVER THE CENTRAL AND SOUTHERN PANHANDLE WINDS SHOULD BE
TRENDING DOWN. CONSIDERING THE CONVECTIVE REGIME, THERE WILL
LIKELY BE SOME GUSTY PERIODS ABOVE THE INDICATED SUSTAINS IN THE
ZONES.

A SHORTWAVE BEHIND THE STRONG SYSTEM LIFTING NORTH THROUGH THE
PANHANDLE TUESDAY WILL EXTEND A SLIGHT THUNDERSTORM THREAT FOR
SOUTHEASTERN GULF AND SOUTHERN PUBLIC ZONES TUESDAY NIGHT. WHILE
NAM STILL INDICATING THE POTENTIAL OF THUNDERSTORMS INTO
WEDNESDAY, HELD OFF ON MENTIONING AT THIS POINT, AS ECMWF AND GFS
BEGIN TO REDUCE INSTABILITY WITH THE BEGINNINGS OF SOME WARMER AIR
ADVECTION ALOFT FROM THE WEST.

FROM WEDNESDAY NIGHT BEYOND, THE MODELS ARE RECOGNIZING A COUPLE
OF SHORTWAVES SKIRTING EASTWARD ACROSS THE GULF OF ALASKA WITHIN A
ZONAL TRACK. ONE SHOULD ARRIVE THE EASTERN GULF ON WEDNESDAY NIGHT
WITH THE SECOND THURSDAY NIGHT/FRIDAY. AS CURRENTLY, MOST OF THE MODELS
ARE INDICATING THE MOST STABLE AIR REMAINING TO THE SOUTH, WE HAVE
LEFT SOUTHEAST WITHIN A CONVECTIVE REGIME ALL WEEK. THE FORECAST
READS AS IF THERE WILL BE NO BREAKS BETWEEN SYSTEMS, BUT
TRUTHFULLY, SHOWERS WILL BECOME SCATTERED AT TIMES BETWEEN
SYSTEMS, BUT UNCERTAINTY OVER TIMING IS STILL GREAT ENOUGH TO
DEMAND GUESSING GAMES SO A WHITEWASH IS NECESSARY.

WHILE WE ARE ON THE SUBJECT OF SHOWERS, WE SHOULD TAKE A QUICK
ASIDE TO CLARIFY WHAT WE MEAN BETWEEN ISOLATED SHOWERS, SCATTERED
SHOWERS, NUMEROUS SHOWERS, AND JUST SHOWERS. EACH DESCRIPTOR IS
ASSOCIATED WITH A PERCENT OF MEASURABLE PRECIPITATION, OR "POP"
FORECAST. ISOLATED SUGGESTS A 10 TO 20 PERCENT CHANCE OF
MEASURABLE PRECIPITATION RECEIVED AT ANY PARTICULAR SPOT, SAY,
WHERE YOU ARE. LIKEWISE, SCATTERED REFERS TO 30 TO 50 PERCENT,
AND NUMEROUS 60 TO 70 PERCENT. CONTRARY TO HOW IT MAY READ,
"NUMEROUS" SHOWERS GENERALLY INDICATES THAT SHOWER COVERAGE WILL
BE SUCH THAT THE CHANCES OF GETTING WET ARE A LITTLE LESS THAN
"SHOWERS" WITHOUT A DESCRIPTOR. SHOWERS WITHOUT A DESCRIPTOR
SUGGESTS A CONFIDENCE THAT MOST EVERYONE WILL GET WET.

WITH A WET WEAK, WE COOLED TEMPERATURES A BIT FOR CLOUDY AND
SHOWERY CONDITIONS, PERHAPS TWO OR THREE DEGREES BELOW NORMAL.
THESE SYSTEMS ARE FAIRLY WEAK AND THE GENERALLY ZONAL FLOW DOES
NOT SUGGEST GREAT QUANTITIES OF RAINFALL.

AFTER THE FRIDAY WAVE SLIDES EAST INTO CANADA, RIDGING WILL
ATTEMPT TO SET UP AHEAD OF A SHARPER TROUGH THAT DEVELOPS INTO AN
UPPER LOW AS IT ARRIVES IN THE SOUTHWEST GULF. THIS SYSTEM LOOKS
TO APPROACH THE PANHANDLE AND THEN DROP SOUTHEAST FOR EARLY NEXT
WEEK. AS THE TOURISTS FLOCK TO SOUTHEAST ALASKA COME EARLY MAY, IT
IS POSSIBLE FOR A BRIEF SPAN OF DRY WEATHER FOR THEIR STAY, AS
WELL AS A DRY BEGINNING OF THE WEEK FOR THOSE OF US WHO CALL OUR
CORNER OF THE GREAT LAND HOME.

USED NAM/EC FOR TUE NIGHT/WED. THEN BLENDED TO GEM, GFS, NAM, AND
EC TO ACCOUNT FOR MODEL SPREAD WITH WAVES COMING IN WED NIGHT
THROUGH FRI. WPC FROM LATE FRIDAY ONWARD. FORECAST CONFIDENCE GOOD
TUESDAY NIGHT/WEDNESDAY, AND FALLS TO AVERAGE WEDNESDAY NIGHT AND
BEYOND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ027.
         STRONG WIND FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR
     AKZ028.
MARINE...GALE WARNING FOR PKZ036-041.
         SMALL CRAFT ADVISORY FOR PKZ012-013-031>035-042-043-051-052.

&&

$$

GARNER/ADKINS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








  [top]

000
FXAK69 PAFG 272032
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1232 PM AKDT MON APR 27 2015

.DISCUSSION...
MODELS CONTINUE TO PERFORM WELL IN THE SHORT TERM WITH MINIMAL
SPREAD NOTED BETWEEN MODEL FAMILIES AND FROM RUN TO RUN. THE
MODELS INITIALIZED WELL AND VERIFIED WELL AGAINST THE 12Z AND 18Z
ANALYSIS. MODEL SPREAD IN THE MID AND LONG TERM HAS TRENDED LESS
THAN THAT OBSERVED OVER THE LAST SEVERAL RUNS.

WEAK FLOW ALOFT WILL CONTINUE THROUGH THE WEEK WITH WEAK UPPER
LEVEL LOWS OVER THE SOUTHERN BERING SEA...THE NORTHERN GULF OF
ALASKA AND THE NORTHERN YUKON. A WEAK UPPER LEVEL HIGH PRESSURE
WILL REMAIN PARKED OVER THE NORTHWEST COAST.

A THERMAL TROUGH STRETCHES FROM NEAR EAGLE TO JUST SOUTH OF
FAIRBANKS AND TO NEAR MCGRATH. 990MB LOW IN THE NORTHERN GULF WILL
DRIFT SLOWLY NORTHEAST AND BE ABSORBED BY A TRIPLE POINT LOW
MOVING NORTH THROUGH THE PANHANDLE. A WEAK LEE SIDE LOW IN THE
SOUTHERN YUKON HAS BROUGHT A MORE MOIST AIRMASS OVER SOUTHEAST
INTERIOR AND THE SOUTH CENTRAL INTERIOR. RAIN SHOWERS AND
ISOLATED THUNDERSTORMS EXPECTED EAST OF DELTA JUNCTION THIS
AFTERNOON AND EVENING. SNOW LEVELS RISE TO AROUND 3000 FT TODAY
THROUGH THE ALASKA RANG PASSES AND WILL FALL AGAIN BELOW PASS
LEVEL TONIGHT. UP TO AN INCH IS POSSIBLE THROUGH THE ALASKA RANGE
PASSES TONIGHT.

AREAS OF DENSE FOG CONTINUE ON THE NORTH SLOPE. EXPECT THE FOG TO
RETREAT TO THE NORTH TO ENCOMPASS ONLY THE COASTAL ZONES BY THIS
AFTERNOON. VISIBILITIES WILL IMPROVE THIS AFTERNOON BUT WILL
LIKELY FALL AGAIN TONIGHT. AREAS OF FOG ALSO IMPACTING PARTS OF
THE WEST COAST ESPECIALLY NORTH OF THE BERING STRAIT HOWEVER THE
LOWER YK DELTA AND EASTERN NORTON SOUND NEAR UNALAKLEET
EXPERIENCING FOG AND LOW CEILINGS WITH MARINE STRATUS AND FOG
TODAY. FOG EXPECTED TO FORM AGAIN IN THESE AREAS TONIGHT.

&&

.FIRE WEATHER...
SOME IMPROVEMENT IN MIN RH VALUES EXPECTED THIS AFTERNOON IN AND
NEAR ALASKA RANGE PASSES...MIDDLE TANANA VALLEY AND TANANA FLATS.
MIN RH VALUES IN THE MID TO LOW 20S ARE EXPECTED IN DRIEST SPOTS
BEFORE SHOWERS DEVELOP THIS AFTERNOON. MIN RH VALUES THIS
AFTERNOON WELL ABOVE 50 PERCENT IN THE UPPER TANANA VALLEY. WINDS
ARE EXPECTED TO REMAIN LIGHT NE TO SE 5 TO 15 MPH HOWEVER VARIABLE
AND GUSTS WINDS CAN BE EXPECTED NEAR SHOWERS. ISOLATED
THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING EAST OF DELTA
JUNCTION...SOUTH OF CHICKEN AND NORTH OF THE ALASKA RANGE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CCC APR 15



000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU










000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU









000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU










000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU










000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU










000
FXAK67 PAJK 271357
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
557 AM AKDT MON APR 27 2015

.SHORT TERM...A VERTICALLY STACKED LOW OVER THE SOUTH CENTRAL GULF
WILL PERSIST THROUGH THE SHORT TERM FORECAST PERIOD WHILE SLOWLY
WEAKENING. AN AREA OF ENHANCED CONVECTION HAS ROTATED AROUND TO
THE NORTHEAST QUADRANT OF THE LOW AND LIGHTNING HAD BEEN DETECTED
OVERNIGHT IN COASTAL MARINE MARINE ZONES 41, 42, 43 AND 51.
LIGHTNING ACTIVITY HAS DIMINISHED IN THE EARLY MORNING HOURS AND
MODELS ARE INDICATING THAT AREAS MOST FAVORABLE FOR CONVECTIVE
ACTIVITY WILL REMAIN OFFSHORE, ROTATING ABOUT THE LOW TO THE
NORTHWEST, AND THEN WEST. THUS, THUNDERSTORMS HAVE NOT BEEN
INCLUDED IN THE ZONE 17 FORECAST THIS MORNING. SHOWERS REMAIN OVER
THE PANHANDLE TODAY AS THE LOW CONTINUES TO SPIN OFF BANDS OF
CONVECTION. FARTHER SOUTH, A LOW HAS FORMED ON THE FRONTAL
BOUNDARY WEST OF THE CALIFORNIA/OREGON BORDER. THIS LOW WILL MAKE
RAPID PROGRESS TO THE NORTH WHILE CONTINUING TO INTENSIFY AND
APPROACH THE DIXON ENTRANCE LATE TONIGHT. AHEAD OF THE LOW,
SHOWERS WILL TRANSFORM TO RAIN AS THE ATMOSPHERE STABILIZES AND
THE ASSOCIATED FRONT MOVES NORTH.

WINDS OVER THE GULF FROM THE FIRST LOW CONTINUE GENERALLY AT HIGH
END SMALL CRAFT INTENSITY OVER THE LOCAL FORECAST DOMAIN, ALTHOUGH ONE
SHIP OBSERVATION IN THE SOUTHEAST QUADRANT REPORTED A SOUTHWEST
WIND OF 35 KTS. SEA STATE OVER THE GULF RANGING FROM 9 TO 14 FEET
WITH 10 TO 11 SECOND SWELL PERIODS. AS THE SECOND LOW INTENSIFIES
AND TRACKS NORTH, WINDS OVER THE SOUTHEAST GULF WILL BACK TO THE
EAST, AND THEN NORTH. STRONGEST WINDS BY LATE TONIGHT SHOULD BE IN
THE DIXON ENTRANCE AND HECATE STRAIT...APPROACHING 40 KTS. WINDS
OVER ZONE 41 AND CLARENCE STRAIT EXPECTED TO REACH 30 KTS, SO NO
GALE WARNINGS ISSUED WITH THE MORNING FORECAST. ALSO HAVE SMALL
CRAFT ADVISORIES OUT FOR SUMNER AND SOUTHERN CHATHAM STRAIT. FARTHER
NORTH, WINDS OVER THE FAR NORTHERN INNER CHANNELS WILL RESPOND TO
THE STRONG NORTHERLY GRADIENT THAT WILL BE CREATED BY THE SECOND
LOW AND REACH SMALL CRAFT INTENSITY OVER LYNN CANAL BY LATE
TONIGHT.

USED A BLEND OF THE 00Z ECMWF AND THE 06Z NAM FOR PRESSURE AD
WIND BASED ON EXCELLENT MODEL AGREEMENT. POP AND QPF A BLEND OF
GFS AND NAM. OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...LOOKS LIKE LOW WILL TRACK ALONG OR JUST A BIT
OFFSHORE THE OUTER COAST TUE WHILE WEAKENING. SOME MODELS SUGGEST
LOW COULD CUT INLAND NEAR CAPE DECISION AND HEAD NWD THRU THE
INNER CHANNELS. THINK PRESENCE OF OLD PARENT LOW OVER THE CENTRAL
GULF WILL HELP STEER THE LOW MORE TO THE NW AS IT ENTERS THE GULF.
AFTER THIS LOW REFORMS INLAND OVER THE SW YUKON TUE NIGHT...WILL
SEE REMAINS OF PARENT LOW DRIFT ACROSS THE ERN GULF AND INTO SE AK
WED. LOOKS LIKE ANOTHER SYSTEM WILL COME INTO THE GULF WED...BUT
APPEARS TO BE FAIRLY WEAK AT THIS POINT. ENDED UP USING A BLEND OF
THE 06Z NAM AND 00Z ECMWF FOR TUE-TUE NIGHT...BUT INCORPORATED
MORE OF THE ECMWF TO KEEP LOW TRACK MORE OFFSHORE.

FOR TUE AND TUE NIGHT...RAIN WILL MOVE NWD ACROSS THE MAIN PART OF
THE PANHANDLE AS LOW MOVES NWD. AFTER LOW PASSES BY...PRECIP WILL
TRANSITION TO SHOWERS ONCE AGAIN. MAY SEE A FEW TSTMS OVER THE FAR
SE GULF AND FAR SRN INNER CHANNELS TUE AFTERNOON. GALE FORCE WINDS
WILL OCCUR ESPECIALLY ON THE S AND E SIDE OF THE LOW...AND MAINLY
OVER THE SE GULF AND SRN INNER CHANNELS. AS LOW CONTINUES FURTHER
N...WINDS WILL FLIP FROM NLY TO SLY AND PICK UP TO SCA LEVELS OVER
THE NRN AREAS LATE TUE AFTERNOON AND EVENING. IT IS POSSIBLE THAT
SOME LAND AREAS MAY NEED STRONG WIND HEADLINES TUE...MAINLY OVER
THE S. THE PAYA AREA WILL LIKELY STAY DRY TUE ALTHOUGH A THREAT
FOR RAIN MAY GET THERE TOWARD THE EVENING.

FOR WED...AS OLD LOW MOVES ONSHORE...WILL CONTINUE TO SEE SHOWERS
OVER THE AREA WITH MOST OF THEM OVER THE SE HALF OF THE AREA.
THINKING THAT SYSTEM WILL WEAKEN ENOUGH TO DIMINISH THREAT FOR ANY
TSTMS BY THIS TIME.

AFTER WED...FORECAST CONFIDENCE DROPS AS MODEL DIFFERENCES
INCREASE. FLOW ALOFT WILL TEND TOWARD A MORE ZONAL CONFIGURATION
WITH SEVERAL SHORTWAVES TRAVERSING EWD IN THIS FLOW. THESE WILL AT
LEAST MAINTAIN A THREAT FOR SOME RAIN OR SHOWER ACTIVITY INTO LATE
WEEK.

&&

.AVIATION...THREAT OF THUNDERSTORM ACTIVITY LIMITED TO THE
IMMEDIATE OUTER COAST, ALTHOUGH CONVECTIVE BUILD UPS AND GUSTY
WINDS IN HEAVIER SHOWERS WILL EXTEND WELL INLAND. NO LLWS, BUT
THIS WILL BE A FACTOR FOR THE SOUTHERN PANHANDLE BY EARLY TUESDAY
MORNING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-035-036-041>043-051-
     052.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU










000
FXAK68 PAFC 271301
AFDAFC

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

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

&&

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

&&

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

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

&&

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

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

&&

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

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

&&

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

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

&&


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

&&

$$

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




000
FXAK68 PAFC 271301
AFDAFC

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

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

&&

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

&&

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

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

&&

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

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

&&

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

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

&&

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

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

&&


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

&&

$$

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



000
FXAK69 PAFG 271023
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
223 AM AKDT MON APR 27 2015

.DISCUSSION...
MODELS FAIRLY SIMILAR THROUGH 60 HOURS. LOW IN THE GULF OF ALASKA WILL
PERSIST THROUGH TUE. SURFACE THERMAL TROUGH WILL CONTINUE TO LIE
OVER THE SOUTHEASTERN INTERIOR THROUGH TUE. THIS WILL BE
RESPONSIBLE FOR PRODUCING A FEW SHOWERS. THE CONVECTIVE
PARAMETERS ARE NOT TO IMPRESSIVE BUT THERE IS AN OUTSIDE
POSSIBILITY OF A THUNDERSTORM FROM DELTA EAST.

THE GFS DOES SOMEHOW DEVELOP A COLD BALL AT 850 NEAR DEADHORSE ON
MON AFTERNOON BUT THE ECMWF AND THE NAM ARE VOID OF THIS. IN
REALITY IT WILL NOT AFFECT MUCH AT THE SURFACE BUT JUST A MYSTERY
OF WHERE THE COLD AIR MATERIALIZES FROM.

EXTENSIVE DENSE FOG ON THE ARCTIC SLOPE AND THE WEST COAST WILL
CONTINUE THROUGH AT LEAST MON. PARALLEL TO ONSHORE FLOW OVER THE
ARCTIC COAST AND THE WEST COAST FROM THE BERING STRAIT NORTHWARD
WILL CONTRIBUTE TO THE FOG AND STRATUS.

&&

.FIRE WEATHER...RH VALUES HAVE INCREASED WITH THE EASTERLY FLOW
FROM THE GULF OF ALASKA. THIS HAS TAKE THE RH VALUES FROM THE
TEENS TO THE 20S AND 30S. THE VALUES SHOULD REMAIN OUT OF THE
TEENS FOR THE NEXT COUPLE OF DAYS AT LEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15



000
FXAK69 PAFG 271023
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
223 AM AKDT MON APR 27 2015

.DISCUSSION...
MODELS FAIRLY SIMILAR THROUGH 60 HOURS. LOW IN THE GULF OF ALASKA WILL
PERSIST THROUGH TUE. SURFACE THERMAL TROUGH WILL CONTINUE TO LIE
OVER THE SOUTHEASTERN INTERIOR THROUGH TUE. THIS WILL BE
RESPONSIBLE FOR PRODUCING A FEW SHOWERS. THE CONVECTIVE
PARAMETERS ARE NOT TO IMPRESSIVE BUT THERE IS AN OUTSIDE
POSSIBILITY OF A THUNDERSTORM FROM DELTA EAST.

THE GFS DOES SOMEHOW DEVELOP A COLD BALL AT 850 NEAR DEADHORSE ON
MON AFTERNOON BUT THE ECMWF AND THE NAM ARE VOID OF THIS. IN
REALITY IT WILL NOT AFFECT MUCH AT THE SURFACE BUT JUST A MYSTERY
OF WHERE THE COLD AIR MATERIALIZES FROM.

EXTENSIVE DENSE FOG ON THE ARCTIC SLOPE AND THE WEST COAST WILL
CONTINUE THROUGH AT LEAST MON. PARALLEL TO ONSHORE FLOW OVER THE
ARCTIC COAST AND THE WEST COAST FROM THE BERING STRAIT NORTHWARD
WILL CONTRIBUTE TO THE FOG AND STRATUS.

&&

.FIRE WEATHER...RH VALUES HAVE INCREASED WITH THE EASTERLY FLOW
FROM THE GULF OF ALASKA. THIS HAS TAKE THE RH VALUES FROM THE
TEENS TO THE 20S AND 30S. THE VALUES SHOULD REMAIN OUT OF THE
TEENS FOR THE NEXT COUPLE OF DAYS AT LEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15



000
FXAK69 PAFG 271023
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
223 AM AKDT MON APR 27 2015

.DISCUSSION...
MODELS FAIRLY SIMILAR THROUGH 60 HOURS. LOW IN THE GULF OF ALASKA WILL
PERSIST THROUGH TUE. SURFACE THERMAL TROUGH WILL CONTINUE TO LIE
OVER THE SOUTHEASTERN INTERIOR THROUGH TUE. THIS WILL BE
RESPONSIBLE FOR PRODUCING A FEW SHOWERS. THE CONVECTIVE
PARAMETERS ARE NOT TO IMPRESSIVE BUT THERE IS AN OUTSIDE
POSSIBILITY OF A THUNDERSTORM FROM DELTA EAST.

THE GFS DOES SOMEHOW DEVELOP A COLD BALL AT 850 NEAR DEADHORSE ON
MON AFTERNOON BUT THE ECMWF AND THE NAM ARE VOID OF THIS. IN
REALITY IT WILL NOT AFFECT MUCH AT THE SURFACE BUT JUST A MYSTERY
OF WHERE THE COLD AIR MATERIALIZES FROM.

EXTENSIVE DENSE FOG ON THE ARCTIC SLOPE AND THE WEST COAST WILL
CONTINUE THROUGH AT LEAST MON. PARALLEL TO ONSHORE FLOW OVER THE
ARCTIC COAST AND THE WEST COAST FROM THE BERING STRAIT NORTHWARD
WILL CONTRIBUTE TO THE FOG AND STRATUS.

&&

.FIRE WEATHER...RH VALUES HAVE INCREASED WITH THE EASTERLY FLOW
FROM THE GULF OF ALASKA. THIS HAS TAKE THE RH VALUES FROM THE
TEENS TO THE 20S AND 30S. THE VALUES SHOULD REMAIN OUT OF THE
TEENS FOR THE NEXT COUPLE OF DAYS AT LEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK69 PAFG 271023
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
223 AM AKDT MON APR 27 2015

.DISCUSSION...
MODELS FAIRLY SIMILAR THROUGH 60 HOURS. LOW IN THE GULF OF ALASKA WILL
PERSIST THROUGH TUE. SURFACE THERMAL TROUGH WILL CONTINUE TO LIE
OVER THE SOUTHEASTERN INTERIOR THROUGH TUE. THIS WILL BE
RESPONSIBLE FOR PRODUCING A FEW SHOWERS. THE CONVECTIVE
PARAMETERS ARE NOT TO IMPRESSIVE BUT THERE IS AN OUTSIDE
POSSIBILITY OF A THUNDERSTORM FROM DELTA EAST.

THE GFS DOES SOMEHOW DEVELOP A COLD BALL AT 850 NEAR DEADHORSE ON
MON AFTERNOON BUT THE ECMWF AND THE NAM ARE VOID OF THIS. IN
REALITY IT WILL NOT AFFECT MUCH AT THE SURFACE BUT JUST A MYSTERY
OF WHERE THE COLD AIR MATERIALIZES FROM.

EXTENSIVE DENSE FOG ON THE ARCTIC SLOPE AND THE WEST COAST WILL
CONTINUE THROUGH AT LEAST MON. PARALLEL TO ONSHORE FLOW OVER THE
ARCTIC COAST AND THE WEST COAST FROM THE BERING STRAIT NORTHWARD
WILL CONTRIBUTE TO THE FOG AND STRATUS.

&&

.FIRE WEATHER...RH VALUES HAVE INCREASED WITH THE EASTERLY FLOW
FROM THE GULF OF ALASKA. THIS HAS TAKE THE RH VALUES FROM THE
TEENS TO THE 20S AND 30S. THE VALUES SHOULD REMAIN OUT OF THE
TEENS FOR THE NEXT COUPLE OF DAYS AT LEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK68 PAFC 270024
AFDAFC

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

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

&&

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

&&

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

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

&&

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

&&

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

&&

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

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

&&


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

&&

$$

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



000
FXAK68 PAFC 270024
AFDAFC

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

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

&&

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

&&

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

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

&&

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

&&

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

&&

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

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

&&


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

&&

$$

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




000
FXAK68 PAFC 270024
AFDAFC

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

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

&&

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

&&

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

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

&&

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

&&

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

&&

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

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

&&


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

&&

$$

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



000
FXAK67 PAJK 262325
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
325 PM AKDT SUN APR 26 2015

.SHORT TERM...THE VERTICALLY STACKED LOW OVER THE WEST CENTRAL
GULF OF ALASKA WILL PERSIST INTO EARLY NEXT WEEK WHILE SLOWLY
WEAKENING. THE ASSOCIATED FRONTAL BAND WILL HAVE HAVE SPREAD
THROUGH THE PANHANDLE THEN ARCS BACK INTO THE EASTERN PACIFIC.
THROUGH LATE TONIGHT AND MONDAY A DEVELOPING WAVE WILL MOVE NORTH
ALONG THE OLD FRONT BUT THEN APPROACH THE SOUTHERN PANHANDLE LATE
MONDAY AFTERNOON.

THE RAIN ACROSS THE PANHANDLE IS TRANSITIONING OVER TO SHOWERS.
THERE IS QUITE A POOL OF COOLER AIR ALOFT AS 500 MB TEMPERATURES
RANGED AS COLD AS -36 C ARE MOVING INTO THE EASTERN GULF. THIS POOL
OF COLD AIR ALONG WITH THE LIFT FROM AN UPPER LEVEL VORTICITY LOBE
ROTATES INTO THE REGION ABOUT THE UPPER LEVEL LOW. THE ADDITIONAL
LIFT WILL BE ENOUGH FOR ISOLATED THUNDERSTORMS TO DEVELOP. THEY
SHOULD STAY PRIMARILY OFF SHORE BUT DO EXPECT THEM TO LIKELY GRAZE
CHICAGOF AND BARANOF ISLANDS LATE TONIGHT AND EARLY MONDAY
MORNING.

WINDS ARE 25 TO 30 OUT OVER THE GULF OF ALASKA AND OUTER
COASTAL REGIONS. A FEW OF THE INNER CHANNELS ARE UP TO SMALL CRAFT
LEVELS BUT ARE PRIMARILY 20 KT OR LESS.

.LONG TERM...SUN AFTERNOON WV IMAGERY SHOWS A SHORTWAVE TROUGH
OVER THE N PAC ROUNDING THE BASE OF AN UPPER LOW CENTERED OVER THE
SRN GULF. LATEST MODEL GUIDANCE INDICATES THE SHORTWAVE WILL EJECT
NE INTO THE NERN PAC BY 06Z TUE...AND THEN LIFT N ACROSS HAIDA
GWAII BY 15Z TUE. THIS FEATURE THEN MOVES N OVER THE SRN/CNTRL
PANHANDLE THROUGH 00Z WED. DETERMINISTIC MODEL SOLUTIONS ARE
SUBSEQUENTLY CONVERGING ON THE DEVELOPMENT OF A COMPACT SURFACE
LOW PRESSURE SYSTEM MOVING N INTO THE PANHANDLE WITH ITS PARENT
UPPER TROUGH. THE 12Z GFS AND NAM WERE FASTER SOLUTIONS WITH THE
NWD MOVEMENT OF THE LOW COMPARED TO THE 12Z GEM AND ECMWF...BUT
THE 18Z GFS AND NAM HAVE TRENDED TOWARD A SLOWER EVOLUTION AS WELL.

AS A RESULT...UPDATED PRESSURE GRIDS REFLECT A HEAVIER WEIGHTING
TOWARD THE GEM/ECMWF...WHICH YIELDS STRENGTHENING NNELY WINDS
DURING TUE MORNING THAT RAPIDLY FLIP TO SLY AFTER THE PASSAGE OF
THE LOW. GALE FORCE WINDS APPEAR PROBABLE OVER CLARENCE STRAIT AS
THIS HAPPENS...WHILE NLY SMALL CRAFT WINDS OVER LYNN CANAL DURING
TUE MORNING/AFTERNOON WILL BECOME SLY SMALL CRAFT WINDS TUE NIGHT.
A SIMILAR EVOLUTION IS EXPECTED FOR STEPHENS PASSAGE AS A 30+ KT
SLY LLJ SPREADS N BY TUE AFTERNOON/EVENING. IN ADDITION...GUSTS
WILL APPROACH STRONG WIND CRITERIA OVER AKZ027-028 AS THE SLY LLJ
DEVELOPS IN THE WAKE OF THE LOW TUE AFTERNOON.

PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE DRAWN NWD WITH THE
PREVIOUSLY MENTIONED SURFACE LOW...WHICH COULD AID IN PERIODS OF
HEAVY RAIN OVER THE SRN/CNTRL PANHANDLE DURING TUE. IN
ADDITION...500 MB TEMPERATURES NEAR -30 C WILL SPREAD EWD ACROSS
THE SRN OUTSIDE WATERS AND PANHANDLE AS THE SHORTWAVE TROUGH LIFTS
N OF THE AREA TUE AFTERNOON. SUBSEQUENT DESTABILIZATION WILL
RESULT IN THE REDEVELOPMENT OF A CONVECTIVE ENVIRONMENT...AS WELL
AS A SLIGHT CHANCE OF THUNDERSTORMS AS MINOR UPPER IMPULSES MOVE
ACROSS THE AREA.

AFTER TUE...MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH THE
LARGE-SCALE UPPER AIR EVOLUTION THROUGH 00Z SAT...WITH DIFFERENCES
IN THE DEVELOPMENT OF AN UPPER RIDGE BECOMING MORE NOTICEABLE BY
SUN AND MON. GFS AND ECMWF WERE USED FOR POP/QPF THROUGH MOST OF
THE WEEK. WPC WAS THEN USED FOR PRESSURE AND POP GUIDANCE 00Z FRI
AND BEYOND...WHICH WAS COMPOSED OF A HEAVY ENSEMBLE BLEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-041>043.

&&

$$

BEZENEK/GARNER

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK67 PAJK 262325
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
325 PM AKDT SUN APR 26 2015

.SHORT TERM...THE VERTICALLY STACKED LOW OVER THE WEST CENTRAL
GULF OF ALASKA WILL PERSIST INTO EARLY NEXT WEEK WHILE SLOWLY
WEAKENING. THE ASSOCIATED FRONTAL BAND WILL HAVE HAVE SPREAD
THROUGH THE PANHANDLE THEN ARCS BACK INTO THE EASTERN PACIFIC.
THROUGH LATE TONIGHT AND MONDAY A DEVELOPING WAVE WILL MOVE NORTH
ALONG THE OLD FRONT BUT THEN APPROACH THE SOUTHERN PANHANDLE LATE
MONDAY AFTERNOON.

THE RAIN ACROSS THE PANHANDLE IS TRANSITIONING OVER TO SHOWERS.
THERE IS QUITE A POOL OF COOLER AIR ALOFT AS 500 MB TEMPERATURES
RANGED AS COLD AS -36 C ARE MOVING INTO THE EASTERN GULF. THIS POOL
OF COLD AIR ALONG WITH THE LIFT FROM AN UPPER LEVEL VORTICITY LOBE
ROTATES INTO THE REGION ABOUT THE UPPER LEVEL LOW. THE ADDITIONAL
LIFT WILL BE ENOUGH FOR ISOLATED THUNDERSTORMS TO DEVELOP. THEY
SHOULD STAY PRIMARILY OFF SHORE BUT DO EXPECT THEM TO LIKELY GRAZE
CHICAGOF AND BARANOF ISLANDS LATE TONIGHT AND EARLY MONDAY
MORNING.

WINDS ARE 25 TO 30 OUT OVER THE GULF OF ALASKA AND OUTER
COASTAL REGIONS. A FEW OF THE INNER CHANNELS ARE UP TO SMALL CRAFT
LEVELS BUT ARE PRIMARILY 20 KT OR LESS.

.LONG TERM...SUN AFTERNOON WV IMAGERY SHOWS A SHORTWAVE TROUGH
OVER THE N PAC ROUNDING THE BASE OF AN UPPER LOW CENTERED OVER THE
SRN GULF. LATEST MODEL GUIDANCE INDICATES THE SHORTWAVE WILL EJECT
NE INTO THE NERN PAC BY 06Z TUE...AND THEN LIFT N ACROSS HAIDA
GWAII BY 15Z TUE. THIS FEATURE THEN MOVES N OVER THE SRN/CNTRL
PANHANDLE THROUGH 00Z WED. DETERMINISTIC MODEL SOLUTIONS ARE
SUBSEQUENTLY CONVERGING ON THE DEVELOPMENT OF A COMPACT SURFACE
LOW PRESSURE SYSTEM MOVING N INTO THE PANHANDLE WITH ITS PARENT
UPPER TROUGH. THE 12Z GFS AND NAM WERE FASTER SOLUTIONS WITH THE
NWD MOVEMENT OF THE LOW COMPARED TO THE 12Z GEM AND ECMWF...BUT
THE 18Z GFS AND NAM HAVE TRENDED TOWARD A SLOWER EVOLUTION AS WELL.

AS A RESULT...UPDATED PRESSURE GRIDS REFLECT A HEAVIER WEIGHTING
TOWARD THE GEM/ECMWF...WHICH YIELDS STRENGTHENING NNELY WINDS
DURING TUE MORNING THAT RAPIDLY FLIP TO SLY AFTER THE PASSAGE OF
THE LOW. GALE FORCE WINDS APPEAR PROBABLE OVER CLARENCE STRAIT AS
THIS HAPPENS...WHILE NLY SMALL CRAFT WINDS OVER LYNN CANAL DURING
TUE MORNING/AFTERNOON WILL BECOME SLY SMALL CRAFT WINDS TUE NIGHT.
A SIMILAR EVOLUTION IS EXPECTED FOR STEPHENS PASSAGE AS A 30+ KT
SLY LLJ SPREADS N BY TUE AFTERNOON/EVENING. IN ADDITION...GUSTS
WILL APPROACH STRONG WIND CRITERIA OVER AKZ027-028 AS THE SLY LLJ
DEVELOPS IN THE WAKE OF THE LOW TUE AFTERNOON.

PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE DRAWN NWD WITH THE
PREVIOUSLY MENTIONED SURFACE LOW...WHICH COULD AID IN PERIODS OF
HEAVY RAIN OVER THE SRN/CNTRL PANHANDLE DURING TUE. IN
ADDITION...500 MB TEMPERATURES NEAR -30 C WILL SPREAD EWD ACROSS
THE SRN OUTSIDE WATERS AND PANHANDLE AS THE SHORTWAVE TROUGH LIFTS
N OF THE AREA TUE AFTERNOON. SUBSEQUENT DESTABILIZATION WILL
RESULT IN THE REDEVELOPMENT OF A CONVECTIVE ENVIRONMENT...AS WELL
AS A SLIGHT CHANCE OF THUNDERSTORMS AS MINOR UPPER IMPULSES MOVE
ACROSS THE AREA.

AFTER TUE...MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH THE
LARGE-SCALE UPPER AIR EVOLUTION THROUGH 00Z SAT...WITH DIFFERENCES
IN THE DEVELOPMENT OF AN UPPER RIDGE BECOMING MORE NOTICEABLE BY
SUN AND MON. GFS AND ECMWF WERE USED FOR POP/QPF THROUGH MOST OF
THE WEEK. WPC WAS THEN USED FOR PRESSURE AND POP GUIDANCE 00Z FRI
AND BEYOND...WHICH WAS COMPOSED OF A HEAVY ENSEMBLE BLEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-041>043.

&&

$$

BEZENEK/GARNER

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 262325
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
325 PM AKDT SUN APR 26 2015

.SHORT TERM...THE VERTICALLY STACKED LOW OVER THE WEST CENTRAL
GULF OF ALASKA WILL PERSIST INTO EARLY NEXT WEEK WHILE SLOWLY
WEAKENING. THE ASSOCIATED FRONTAL BAND WILL HAVE HAVE SPREAD
THROUGH THE PANHANDLE THEN ARCS BACK INTO THE EASTERN PACIFIC.
THROUGH LATE TONIGHT AND MONDAY A DEVELOPING WAVE WILL MOVE NORTH
ALONG THE OLD FRONT BUT THEN APPROACH THE SOUTHERN PANHANDLE LATE
MONDAY AFTERNOON.

THE RAIN ACROSS THE PANHANDLE IS TRANSITIONING OVER TO SHOWERS.
THERE IS QUITE A POOL OF COOLER AIR ALOFT AS 500 MB TEMPERATURES
RANGED AS COLD AS -36 C ARE MOVING INTO THE EASTERN GULF. THIS POOL
OF COLD AIR ALONG WITH THE LIFT FROM AN UPPER LEVEL VORTICITY LOBE
ROTATES INTO THE REGION ABOUT THE UPPER LEVEL LOW. THE ADDITIONAL
LIFT WILL BE ENOUGH FOR ISOLATED THUNDERSTORMS TO DEVELOP. THEY
SHOULD STAY PRIMARILY OFF SHORE BUT DO EXPECT THEM TO LIKELY GRAZE
CHICAGOF AND BARANOF ISLANDS LATE TONIGHT AND EARLY MONDAY
MORNING.

WINDS ARE 25 TO 30 OUT OVER THE GULF OF ALASKA AND OUTER
COASTAL REGIONS. A FEW OF THE INNER CHANNELS ARE UP TO SMALL CRAFT
LEVELS BUT ARE PRIMARILY 20 KT OR LESS.

.LONG TERM...SUN AFTERNOON WV IMAGERY SHOWS A SHORTWAVE TROUGH
OVER THE N PAC ROUNDING THE BASE OF AN UPPER LOW CENTERED OVER THE
SRN GULF. LATEST MODEL GUIDANCE INDICATES THE SHORTWAVE WILL EJECT
NE INTO THE NERN PAC BY 06Z TUE...AND THEN LIFT N ACROSS HAIDA
GWAII BY 15Z TUE. THIS FEATURE THEN MOVES N OVER THE SRN/CNTRL
PANHANDLE THROUGH 00Z WED. DETERMINISTIC MODEL SOLUTIONS ARE
SUBSEQUENTLY CONVERGING ON THE DEVELOPMENT OF A COMPACT SURFACE
LOW PRESSURE SYSTEM MOVING N INTO THE PANHANDLE WITH ITS PARENT
UPPER TROUGH. THE 12Z GFS AND NAM WERE FASTER SOLUTIONS WITH THE
NWD MOVEMENT OF THE LOW COMPARED TO THE 12Z GEM AND ECMWF...BUT
THE 18Z GFS AND NAM HAVE TRENDED TOWARD A SLOWER EVOLUTION AS WELL.

AS A RESULT...UPDATED PRESSURE GRIDS REFLECT A HEAVIER WEIGHTING
TOWARD THE GEM/ECMWF...WHICH YIELDS STRENGTHENING NNELY WINDS
DURING TUE MORNING THAT RAPIDLY FLIP TO SLY AFTER THE PASSAGE OF
THE LOW. GALE FORCE WINDS APPEAR PROBABLE OVER CLARENCE STRAIT AS
THIS HAPPENS...WHILE NLY SMALL CRAFT WINDS OVER LYNN CANAL DURING
TUE MORNING/AFTERNOON WILL BECOME SLY SMALL CRAFT WINDS TUE NIGHT.
A SIMILAR EVOLUTION IS EXPECTED FOR STEPHENS PASSAGE AS A 30+ KT
SLY LLJ SPREADS N BY TUE AFTERNOON/EVENING. IN ADDITION...GUSTS
WILL APPROACH STRONG WIND CRITERIA OVER AKZ027-028 AS THE SLY LLJ
DEVELOPS IN THE WAKE OF THE LOW TUE AFTERNOON.

PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE DRAWN NWD WITH THE
PREVIOUSLY MENTIONED SURFACE LOW...WHICH COULD AID IN PERIODS OF
HEAVY RAIN OVER THE SRN/CNTRL PANHANDLE DURING TUE. IN
ADDITION...500 MB TEMPERATURES NEAR -30 C WILL SPREAD EWD ACROSS
THE SRN OUTSIDE WATERS AND PANHANDLE AS THE SHORTWAVE TROUGH LIFTS
N OF THE AREA TUE AFTERNOON. SUBSEQUENT DESTABILIZATION WILL
RESULT IN THE REDEVELOPMENT OF A CONVECTIVE ENVIRONMENT...AS WELL
AS A SLIGHT CHANCE OF THUNDERSTORMS AS MINOR UPPER IMPULSES MOVE
ACROSS THE AREA.

AFTER TUE...MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH THE
LARGE-SCALE UPPER AIR EVOLUTION THROUGH 00Z SAT...WITH DIFFERENCES
IN THE DEVELOPMENT OF AN UPPER RIDGE BECOMING MORE NOTICEABLE BY
SUN AND MON. GFS AND ECMWF WERE USED FOR POP/QPF THROUGH MOST OF
THE WEEK. WPC WAS THEN USED FOR PRESSURE AND POP GUIDANCE 00Z FRI
AND BEYOND...WHICH WAS COMPOSED OF A HEAVY ENSEMBLE BLEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-041>043.

&&

$$

BEZENEK/GARNER

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK67 PAJK 262325
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
325 PM AKDT SUN APR 26 2015

.SHORT TERM...THE VERTICALLY STACKED LOW OVER THE WEST CENTRAL
GULF OF ALASKA WILL PERSIST INTO EARLY NEXT WEEK WHILE SLOWLY
WEAKENING. THE ASSOCIATED FRONTAL BAND WILL HAVE HAVE SPREAD
THROUGH THE PANHANDLE THEN ARCS BACK INTO THE EASTERN PACIFIC.
THROUGH LATE TONIGHT AND MONDAY A DEVELOPING WAVE WILL MOVE NORTH
ALONG THE OLD FRONT BUT THEN APPROACH THE SOUTHERN PANHANDLE LATE
MONDAY AFTERNOON.

THE RAIN ACROSS THE PANHANDLE IS TRANSITIONING OVER TO SHOWERS.
THERE IS QUITE A POOL OF COOLER AIR ALOFT AS 500 MB TEMPERATURES
RANGED AS COLD AS -36 C ARE MOVING INTO THE EASTERN GULF. THIS POOL
OF COLD AIR ALONG WITH THE LIFT FROM AN UPPER LEVEL VORTICITY LOBE
ROTATES INTO THE REGION ABOUT THE UPPER LEVEL LOW. THE ADDITIONAL
LIFT WILL BE ENOUGH FOR ISOLATED THUNDERSTORMS TO DEVELOP. THEY
SHOULD STAY PRIMARILY OFF SHORE BUT DO EXPECT THEM TO LIKELY GRAZE
CHICAGOF AND BARANOF ISLANDS LATE TONIGHT AND EARLY MONDAY
MORNING.

WINDS ARE 25 TO 30 OUT OVER THE GULF OF ALASKA AND OUTER
COASTAL REGIONS. A FEW OF THE INNER CHANNELS ARE UP TO SMALL CRAFT
LEVELS BUT ARE PRIMARILY 20 KT OR LESS.

.LONG TERM...SUN AFTERNOON WV IMAGERY SHOWS A SHORTWAVE TROUGH
OVER THE N PAC ROUNDING THE BASE OF AN UPPER LOW CENTERED OVER THE
SRN GULF. LATEST MODEL GUIDANCE INDICATES THE SHORTWAVE WILL EJECT
NE INTO THE NERN PAC BY 06Z TUE...AND THEN LIFT N ACROSS HAIDA
GWAII BY 15Z TUE. THIS FEATURE THEN MOVES N OVER THE SRN/CNTRL
PANHANDLE THROUGH 00Z WED. DETERMINISTIC MODEL SOLUTIONS ARE
SUBSEQUENTLY CONVERGING ON THE DEVELOPMENT OF A COMPACT SURFACE
LOW PRESSURE SYSTEM MOVING N INTO THE PANHANDLE WITH ITS PARENT
UPPER TROUGH. THE 12Z GFS AND NAM WERE FASTER SOLUTIONS WITH THE
NWD MOVEMENT OF THE LOW COMPARED TO THE 12Z GEM AND ECMWF...BUT
THE 18Z GFS AND NAM HAVE TRENDED TOWARD A SLOWER EVOLUTION AS WELL.

AS A RESULT...UPDATED PRESSURE GRIDS REFLECT A HEAVIER WEIGHTING
TOWARD THE GEM/ECMWF...WHICH YIELDS STRENGTHENING NNELY WINDS
DURING TUE MORNING THAT RAPIDLY FLIP TO SLY AFTER THE PASSAGE OF
THE LOW. GALE FORCE WINDS APPEAR PROBABLE OVER CLARENCE STRAIT AS
THIS HAPPENS...WHILE NLY SMALL CRAFT WINDS OVER LYNN CANAL DURING
TUE MORNING/AFTERNOON WILL BECOME SLY SMALL CRAFT WINDS TUE NIGHT.
A SIMILAR EVOLUTION IS EXPECTED FOR STEPHENS PASSAGE AS A 30+ KT
SLY LLJ SPREADS N BY TUE AFTERNOON/EVENING. IN ADDITION...GUSTS
WILL APPROACH STRONG WIND CRITERIA OVER AKZ027-028 AS THE SLY LLJ
DEVELOPS IN THE WAKE OF THE LOW TUE AFTERNOON.

PW VALUES NEAR 0.8 INCH ARE FORECAST TO BE DRAWN NWD WITH THE
PREVIOUSLY MENTIONED SURFACE LOW...WHICH COULD AID IN PERIODS OF
HEAVY RAIN OVER THE SRN/CNTRL PANHANDLE DURING TUE. IN
ADDITION...500 MB TEMPERATURES NEAR -30 C WILL SPREAD EWD ACROSS
THE SRN OUTSIDE WATERS AND PANHANDLE AS THE SHORTWAVE TROUGH LIFTS
N OF THE AREA TUE AFTERNOON. SUBSEQUENT DESTABILIZATION WILL
RESULT IN THE REDEVELOPMENT OF A CONVECTIVE ENVIRONMENT...AS WELL
AS A SLIGHT CHANCE OF THUNDERSTORMS AS MINOR UPPER IMPULSES MOVE
ACROSS THE AREA.

AFTER TUE...MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH THE
LARGE-SCALE UPPER AIR EVOLUTION THROUGH 00Z SAT...WITH DIFFERENCES
IN THE DEVELOPMENT OF AN UPPER RIDGE BECOMING MORE NOTICEABLE BY
SUN AND MON. GFS AND ECMWF WERE USED FOR POP/QPF THROUGH MOST OF
THE WEEK. WPC WAS THEN USED FOR PRESSURE AND POP GUIDANCE 00Z FRI
AND BEYOND...WHICH WAS COMPOSED OF A HEAVY ENSEMBLE BLEND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-041>043.

&&

$$

BEZENEK/GARNER

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK69 PAFG 262142
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
142 PM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS INITIALIZED WELL AND VERIFIED WELL AGAINST THE 12Z AND 18Z
ANALYSIS. MINIMAL SPREAD EXISTS BETWEEN MODEL FAMILIES AND RUN TO
RUN THROUGH THE SHORT TERM HOWEVER MODELS SPREAD INCREASES
CONSIDERABLY IN THE MID TERM AND CONTINUES THROUGH THE LONG TERM.

THERMAL TROUGH CONTINUES OVER THE SOUTHERN INTERIOR WITH RH
VALUES IN THE TEENS AND 20S EXPECTED AGAIN THIS AFTERNOON. WINDS
ARE LIGHT. WINDS ALOFT AND AT THE SURFACE REMAIN LIGHT OVER MUCH
OF THE FORECAST AREA. THE LOW WINDS ARE LIMITING THE FIRE WEATHER
CONCERNS IN THE SOUTHERN INTERIOR WHILE AIDING LOW CEILINGS AND
FOG OVER MUCH OF THE COASTAL AREAS OF THE NORTH SLOPE AND WEST
COAST. DENSE FOG THIS MORNING OVER THE COASTAL SECTIONS OF THE
NORTH SLOPE HAVE ENDED AS THE FOG HAS THINNED. NOT MUCH CHANGE
EXPECTED ON THE NORTH SLOPE TONIGHT AND INTO MONDAY WITH AREAS OF
FOG PERHAPS BECOMING DENSE AGAIN TONIGHT ALONG THE COAST. THE WEST
COAST ESPECIALLY NORTH OF THE BERING STRAIT MAY ALSO SEE MORE FOG
OVERNIGHT.

A 986 MB LOW IN THE CENTRAL GULF OF ALASKA WILL CONTINUE TO SWING
A FRONT INTO THE SOUTHERN YUKON AND SOUTHEAST ALASKA MONDAY
MORNING. A WEAK LEE SIDE LOW FORMS OVER THE YUKON NEAR BEAVER AND
MERGES WITH THE REMAINS OF THE THERMAL TROUGH OVER THE SOUTHERN
INTERIOR. MOISTURE MOVES INTO SOUTHEAST ALASKA WITH SCATTERED TO
NUMEROUS RAIN SHOWERS AT LOWER ELEVATIONS AND MIXED RAIN AND SNOW
AT HIGHER ELEVATIONS. AN ISOLATED THUNDERSTORM IS POSSIBLE EAST OF
DELTA JUNCTION BUT MORE FAVORED ALONG THE ALCAN BORDER AS JUST
NEGATIVE LIFTED INDEX AND CAPE VALUES AROUND 200 NUDGE INTO THE
AREA.



&&

.FIRE WEATHER...
RH VALUES WILL RECOVER INTO THE 70S AT MOST LOCATIONS IN THE
SOUTHEAST INTERIOR TONIGHT AS MOIST AIRMASS MOVES INTO THE AREA
FROM THE SOUTHEAST. MIN RH VALUES TOMORROW ARE EXPECTED TO BE IN
THE 20S AS COMPARED TO THE TEENS TODAY. WINDS ARE EXPECTED TO
REMAIN LIGHT OVERALL HOWEVER GUSTY AN VARIABLE WINDS CAN BE
EXPECTED TOMORROW NEAR SHOWERS AND ANY THUNDERSTORMS THAT DEVELOP
TOMORROW.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CCC APR 15



000
FXAK69 PAFG 262142
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
142 PM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS INITIALIZED WELL AND VERIFIED WELL AGAINST THE 12Z AND 18Z
ANALYSIS. MINIMAL SPREAD EXISTS BETWEEN MODEL FAMILIES AND RUN TO
RUN THROUGH THE SHORT TERM HOWEVER MODELS SPREAD INCREASES
CONSIDERABLY IN THE MID TERM AND CONTINUES THROUGH THE LONG TERM.

THERMAL TROUGH CONTINUES OVER THE SOUTHERN INTERIOR WITH RH
VALUES IN THE TEENS AND 20S EXPECTED AGAIN THIS AFTERNOON. WINDS
ARE LIGHT. WINDS ALOFT AND AT THE SURFACE REMAIN LIGHT OVER MUCH
OF THE FORECAST AREA. THE LOW WINDS ARE LIMITING THE FIRE WEATHER
CONCERNS IN THE SOUTHERN INTERIOR WHILE AIDING LOW CEILINGS AND
FOG OVER MUCH OF THE COASTAL AREAS OF THE NORTH SLOPE AND WEST
COAST. DENSE FOG THIS MORNING OVER THE COASTAL SECTIONS OF THE
NORTH SLOPE HAVE ENDED AS THE FOG HAS THINNED. NOT MUCH CHANGE
EXPECTED ON THE NORTH SLOPE TONIGHT AND INTO MONDAY WITH AREAS OF
FOG PERHAPS BECOMING DENSE AGAIN TONIGHT ALONG THE COAST. THE WEST
COAST ESPECIALLY NORTH OF THE BERING STRAIT MAY ALSO SEE MORE FOG
OVERNIGHT.

A 986 MB LOW IN THE CENTRAL GULF OF ALASKA WILL CONTINUE TO SWING
A FRONT INTO THE SOUTHERN YUKON AND SOUTHEAST ALASKA MONDAY
MORNING. A WEAK LEE SIDE LOW FORMS OVER THE YUKON NEAR BEAVER AND
MERGES WITH THE REMAINS OF THE THERMAL TROUGH OVER THE SOUTHERN
INTERIOR. MOISTURE MOVES INTO SOUTHEAST ALASKA WITH SCATTERED TO
NUMEROUS RAIN SHOWERS AT LOWER ELEVATIONS AND MIXED RAIN AND SNOW
AT HIGHER ELEVATIONS. AN ISOLATED THUNDERSTORM IS POSSIBLE EAST OF
DELTA JUNCTION BUT MORE FAVORED ALONG THE ALCAN BORDER AS JUST
NEGATIVE LIFTED INDEX AND CAPE VALUES AROUND 200 NUDGE INTO THE
AREA.



&&

.FIRE WEATHER...
RH VALUES WILL RECOVER INTO THE 70S AT MOST LOCATIONS IN THE
SOUTHEAST INTERIOR TONIGHT AS MOIST AIRMASS MOVES INTO THE AREA
FROM THE SOUTHEAST. MIN RH VALUES TOMORROW ARE EXPECTED TO BE IN
THE 20S AS COMPARED TO THE TEENS TODAY. WINDS ARE EXPECTED TO
REMAIN LIGHT OVERALL HOWEVER GUSTY AN VARIABLE WINDS CAN BE
EXPECTED TOMORROW NEAR SHOWERS AND ANY THUNDERSTORMS THAT DEVELOP
TOMORROW.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CCC APR 15




000
FXAK67 PAJK 261358
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
558 AM AKDT SUN APR 26 2015

.SHORT TERM...A GALE FORCE LOW HAS MOVED INTO THE SOUTH CENTRAL
GULF AND THE ASSOCIATED FRONT LIES JUST OFF THE OUTER COAST.
SATELLITE IMAGERY SHOWS EXTENSIVE CLOUD COVER WELL INLAND, BUT
SURFACE OBSERVATIONS ARE INDICATING THAT MUCH OF THIS IS SOMEWHAT
HIGH CEILINGS. RAIN BEGAN FALLING IN THE PRE-DAWN HOURS IN BOTH
SITKA AND KLAWOCK. RAIN WILL SPREAD INLAND THROUGH THE DAY BEFORE
TRANSITIONING TO SHOWERS LATE THIS AFTERNOON OR EARLY EVENING.
EVIDENCE OF COLD AIR ALOFT CAN BE SEEN PUSHING EAST OVER THE GULF
ON THE BACK SIDE OF THE FRONT. A POST FRONTAL SHORT WAVE TROUGH
SOUTH OF KODIAK IN THE SOUTHWEST QUADRANT OF THE PRIMARY LOW WILL
ROTATE AROUND THE LOW THROUGH THE DAY AND SWING A STRONG LOBE OF
MID LEVEL VORTICITY INTO THE EASTERN GULF. THIS WILL PROVIDE THE
UPPER LEVEL SUPPORT NECESSARY TO GENERATE SIGNIFICANT CONVECTIVE
ACTIVITY IN THE WAKE OF THE FRONT. THUS SLIGHT CHANCE OF
THUNDERSTORMS INTRODUCED BY YESTERDAY`S DAY SHIFT WERE RETAINED IN
THIS FORECAST ISSUANCE FOR TONIGHT.

THIS SYSTEM IS ALREADY FULLY OCCLUDED. AS SUCH, NO WARM AIR
ADVECTION OF ANY SIGNIFICANCE IS EXPECTED AND SOME LOCATIONS MAY
SEE THEIR HIGH TEMPERATURES FOR THE DAY OCCURRING THIS MORNING
BEFORE TEMPS BEGIN TO FALL AS THE COLDER AIRMASS MOVES IN. LOOK
FOR HIGHS IN THE MID TO LOWER 50S TODAY WITH OVERNIGHT LOWS
TONIGHT IN THE LOWER 40S OR UPPER 30S.

BUOY DATA OVER THE GULF IS LIMITED, BUT OBSERVATIONS ARE
INDICATING THAT MAX WINDS ASSOCIATED WITH THIS FRONT ARE 35 TO 40
KTS WITH GUSTS TO 60 KTS.STRONG WIND HEADLINE HAS BEEN MAINTAINED
THROUGH 10 AM THIS MORNING FOR ZONE 27 AND ADDED TO ZONE 23 FOR
THE SAME TIME PERIOD. THINK WIND GUSTS OVER KETCHIKAN WILL MAX OUT
AT 35 MPH, SO HAVE NOT INCLUDED ZONE 28. AS THE FRONT PUSHES
INLAND, GUSTS TO 25 MPH WILL SPREAD OVER ZONE 26 AND THEN MOVE
THROUGH THE JUNEAU AREA LATER THIS AFTERNOON AND EARLY EVENING.
MARINERS SHOULD BE MINDFUL OF THE POTENTIAL FOR GUSTY CONDITIONS ABOVE
THE STEADY STATE SMALL CRAFT WINDS OVER THE INNER CHANNELS AS THE FRONT
MOVES THROUGH.

USED A BLEND OF GEM AND ECMWF FOR UPDATES TO PRESSURE AND WIND.
POP AND QPF FROM GEM, GFS, AND ECMWF. OVERALL FORECAST CONFIDENCE
IS AVERAGE.

.LONG TERM...STILL A TRICKY FORECAST FOR MON-TUE DUE TO LOW
PRESSURE WAVE DEVELOPMENT THAT THE MODELS ARE STRUGGLING WITH. THE
MAIN ISSUE IS INTERACTION BETWEEN A SHORTWAVE DIVING INTO THE BASE
OF THE UPPER TROF OVER THE ERN PAC AND SRN STREAM SHORTWAVE
LIFTING NEWD FROM N OF HAWAII. ECMWF SHOWED MOST INTENSE
DEVELOPMENT AND WAS SLOWEST TO LIFT SYSTEM NWD...WHILE THE GEM/GFS
WERE WEAKER AND FASTER. NAM STILL DOES NOT SHOW MUCH DEVELOPMENT
WITH THIS SYSTEM. DUE TO THE DIFFERENCES...DECIDED THAT WHAT WAS IN
PREVIOUS FORECAST LOOKED REASONABLE AS FAR AS THAT FEATURE
GOES...SO ENDED UP MAKING MAINLY SMALL CHANGES TO THAT TIME FRAME.

FOR MON...BANDS OF SHOWERS AROUND THE MAIN LOW WILL CONTINUE TO
AFFECT MOST OF THE AREA...BUT AN AREA OF STEADIER RAIN IS LIKELY
TO MOVE NWD INTO THE SRN AREA AS A LOW PRESSURE WAVE MOVES NNE
TOWARD THE AREA. THE WARM ADVECTION WITH THIS FEATURE WILL ALSO
DIMINISH THREAT FOR TSTMS OVER THE ERN GULF FROM THE S...ALTHOUGH
THE NE GULF WILL REMAIN MOSTLY UNDER THE COLDER AIR ALOFT THRU MON.
GIVEN THE UNCERTAINTY WITH THE LOW PRESSURE WAVE...TIMING ERRORS
ARE POSSIBLE WITH ARRIVAL OF STEADIER PRECIP AND STABILIZATION
OVER THE SE GULF. DECIDED TO USE THE GFS IDEA ON BOTH SINCE IT HAD
SOME SUPPORT FROM THE GEM. ALSO...THE NAM LOOKED TOO UNSTABLE OVER
THE FAR SE GULF FOR TOO LONG AS IT TAKES A MUCH WEAKER LOW PRESSURE
WAVE FURTHER SE AND DOES NOT SHOW THE WARMING ALOFT OVER THE SE GULF.

FOR MON NIGHT...LOOKS LIKE STEADIER PRECIP WILL MOVE NWD THRU THE
MAIN PART OF THE PANHANDLE AS WAVE LIFTS N THRU THE SERN INNER
CHANNELS. MOST OF THE ERN GULF WILL STAY SHOWERY NEAR THE MAIN LOW
CENTER. THE NE GULF COAST LOOKS TO HAVE A BREAK IN PRECIP AS
OFFSHORE FLOW INCREASES DUE TO BOTH THE MAIN LOW AND THE WAVE TO
THE E OF IT.

FOR TUE-WED...PRECIP SHOULD BE SHOWERY AREA WIDE AS MAIN LOW
BEGINS TO DRIFT INTO THE ERN GULF AND WEAKENS...BUT KEEPS ONSHORE
FLOW GOING OVER THE MAIN PART OF THE PANHANDLE. TEMPS IN COLD POOL
ALOFT SHOULD SLOWLY WARM...AND THIS WILL DIMINISH THREAT FOR ANY
TSTM ACTIVITY. THE SHOWERS AND ONSHORE FLOW WILL KEEP TEMPS A BIT
COOLER THAN AVERAGE DURING THE DAY...BUT THE CLOUD COVER WILL KEEP
MILDER NIGHTTIME TEMPS AS WELL.

AFTER WED...ANOTHER SYSTEM MAY AFFECT THE AREA FOR WED NIGHT AND
THU BUT MODELS DIFFER ON TIMING AND TRACK OF IT. MODEL DIFFERENCES
INCREASE LATER IN THE WEEK...BUT SOME HINT OF A DRIER PATTERN MAY
BE EMERGING AS SIGNALS FOR STRONGER RIDGING OVER THE GULF ARE
DEVELOPING IN THE MODELS. ENDED UP GOING WITH WPC FOR THE MOST
PART FOR THIS PERIOD...WHICH SHOWS GENERALLY DECREASING POPS THRU
NEXT WEEKEND.

&&

.AVIATION...STRONG LOW LEVEL JET WITH 65 TO 70 KTS OF WIND AT
850MB WILL RESULT IN LOW LEVEL WIND SHEAR OF MUCH OF SOUTHEAST
ALASKA THROUGH LATE MORNING OR EARLY AFTERNOON. MOST SEVERE
CONDITIONS OCCURRING THIS MORNING AND OVER SOUTHERN LOCATIONS.
CEILINGS EXPECTED TO BE MVMC OR BETTER FOR THE MOST PART WITH
LOWEST CONDITIONS DUE TO REDUCTIONS INVISIBILITY IN HEAVY
RAIN/SHOWERS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 10 AM AKDT THIS MORNING FOR AKZ023-027.
MARINE...GALE WARNING FOR PKZ036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>035.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 261358
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
558 AM AKDT SUN APR 26 2015

.SHORT TERM...A GALE FORCE LOW HAS MOVED INTO THE SOUTH CENTRAL
GULF AND THE ASSOCIATED FRONT LIES JUST OFF THE OUTER COAST.
SATELLITE IMAGERY SHOWS EXTENSIVE CLOUD COVER WELL INLAND, BUT
SURFACE OBSERVATIONS ARE INDICATING THAT MUCH OF THIS IS SOMEWHAT
HIGH CEILINGS. RAIN BEGAN FALLING IN THE PRE-DAWN HOURS IN BOTH
SITKA AND KLAWOCK. RAIN WILL SPREAD INLAND THROUGH THE DAY BEFORE
TRANSITIONING TO SHOWERS LATE THIS AFTERNOON OR EARLY EVENING.
EVIDENCE OF COLD AIR ALOFT CAN BE SEEN PUSHING EAST OVER THE GULF
ON THE BACK SIDE OF THE FRONT. A POST FRONTAL SHORT WAVE TROUGH
SOUTH OF KODIAK IN THE SOUTHWEST QUADRANT OF THE PRIMARY LOW WILL
ROTATE AROUND THE LOW THROUGH THE DAY AND SWING A STRONG LOBE OF
MID LEVEL VORTICITY INTO THE EASTERN GULF. THIS WILL PROVIDE THE
UPPER LEVEL SUPPORT NECESSARY TO GENERATE SIGNIFICANT CONVECTIVE
ACTIVITY IN THE WAKE OF THE FRONT. THUS SLIGHT CHANCE OF
THUNDERSTORMS INTRODUCED BY YESTERDAY`S DAY SHIFT WERE RETAINED IN
THIS FORECAST ISSUANCE FOR TONIGHT.

THIS SYSTEM IS ALREADY FULLY OCCLUDED. AS SUCH, NO WARM AIR
ADVECTION OF ANY SIGNIFICANCE IS EXPECTED AND SOME LOCATIONS MAY
SEE THEIR HIGH TEMPERATURES FOR THE DAY OCCURRING THIS MORNING
BEFORE TEMPS BEGIN TO FALL AS THE COLDER AIRMASS MOVES IN. LOOK
FOR HIGHS IN THE MID TO LOWER 50S TODAY WITH OVERNIGHT LOWS
TONIGHT IN THE LOWER 40S OR UPPER 30S.

BUOY DATA OVER THE GULF IS LIMITED, BUT OBSERVATIONS ARE
INDICATING THAT MAX WINDS ASSOCIATED WITH THIS FRONT ARE 35 TO 40
KTS WITH GUSTS TO 60 KTS.STRONG WIND HEADLINE HAS BEEN MAINTAINED
THROUGH 10 AM THIS MORNING FOR ZONE 27 AND ADDED TO ZONE 23 FOR
THE SAME TIME PERIOD. THINK WIND GUSTS OVER KETCHIKAN WILL MAX OUT
AT 35 MPH, SO HAVE NOT INCLUDED ZONE 28. AS THE FRONT PUSHES
INLAND, GUSTS TO 25 MPH WILL SPREAD OVER ZONE 26 AND THEN MOVE
THROUGH THE JUNEAU AREA LATER THIS AFTERNOON AND EARLY EVENING.
MARINERS SHOULD BE MINDFUL OF THE POTENTIAL FOR GUSTY CONDITIONS ABOVE
THE STEADY STATE SMALL CRAFT WINDS OVER THE INNER CHANNELS AS THE FRONT
MOVES THROUGH.

USED A BLEND OF GEM AND ECMWF FOR UPDATES TO PRESSURE AND WIND.
POP AND QPF FROM GEM, GFS, AND ECMWF. OVERALL FORECAST CONFIDENCE
IS AVERAGE.

.LONG TERM...STILL A TRICKY FORECAST FOR MON-TUE DUE TO LOW
PRESSURE WAVE DEVELOPMENT THAT THE MODELS ARE STRUGGLING WITH. THE
MAIN ISSUE IS INTERACTION BETWEEN A SHORTWAVE DIVING INTO THE BASE
OF THE UPPER TROF OVER THE ERN PAC AND SRN STREAM SHORTWAVE
LIFTING NEWD FROM N OF HAWAII. ECMWF SHOWED MOST INTENSE
DEVELOPMENT AND WAS SLOWEST TO LIFT SYSTEM NWD...WHILE THE GEM/GFS
WERE WEAKER AND FASTER. NAM STILL DOES NOT SHOW MUCH DEVELOPMENT
WITH THIS SYSTEM. DUE TO THE DIFFERENCES...DECIDED THAT WHAT WAS IN
PREVIOUS FORECAST LOOKED REASONABLE AS FAR AS THAT FEATURE
GOES...SO ENDED UP MAKING MAINLY SMALL CHANGES TO THAT TIME FRAME.

FOR MON...BANDS OF SHOWERS AROUND THE MAIN LOW WILL CONTINUE TO
AFFECT MOST OF THE AREA...BUT AN AREA OF STEADIER RAIN IS LIKELY
TO MOVE NWD INTO THE SRN AREA AS A LOW PRESSURE WAVE MOVES NNE
TOWARD THE AREA. THE WARM ADVECTION WITH THIS FEATURE WILL ALSO
DIMINISH THREAT FOR TSTMS OVER THE ERN GULF FROM THE S...ALTHOUGH
THE NE GULF WILL REMAIN MOSTLY UNDER THE COLDER AIR ALOFT THRU MON.
GIVEN THE UNCERTAINTY WITH THE LOW PRESSURE WAVE...TIMING ERRORS
ARE POSSIBLE WITH ARRIVAL OF STEADIER PRECIP AND STABILIZATION
OVER THE SE GULF. DECIDED TO USE THE GFS IDEA ON BOTH SINCE IT HAD
SOME SUPPORT FROM THE GEM. ALSO...THE NAM LOOKED TOO UNSTABLE OVER
THE FAR SE GULF FOR TOO LONG AS IT TAKES A MUCH WEAKER LOW PRESSURE
WAVE FURTHER SE AND DOES NOT SHOW THE WARMING ALOFT OVER THE SE GULF.

FOR MON NIGHT...LOOKS LIKE STEADIER PRECIP WILL MOVE NWD THRU THE
MAIN PART OF THE PANHANDLE AS WAVE LIFTS N THRU THE SERN INNER
CHANNELS. MOST OF THE ERN GULF WILL STAY SHOWERY NEAR THE MAIN LOW
CENTER. THE NE GULF COAST LOOKS TO HAVE A BREAK IN PRECIP AS
OFFSHORE FLOW INCREASES DUE TO BOTH THE MAIN LOW AND THE WAVE TO
THE E OF IT.

FOR TUE-WED...PRECIP SHOULD BE SHOWERY AREA WIDE AS MAIN LOW
BEGINS TO DRIFT INTO THE ERN GULF AND WEAKENS...BUT KEEPS ONSHORE
FLOW GOING OVER THE MAIN PART OF THE PANHANDLE. TEMPS IN COLD POOL
ALOFT SHOULD SLOWLY WARM...AND THIS WILL DIMINISH THREAT FOR ANY
TSTM ACTIVITY. THE SHOWERS AND ONSHORE FLOW WILL KEEP TEMPS A BIT
COOLER THAN AVERAGE DURING THE DAY...BUT THE CLOUD COVER WILL KEEP
MILDER NIGHTTIME TEMPS AS WELL.

AFTER WED...ANOTHER SYSTEM MAY AFFECT THE AREA FOR WED NIGHT AND
THU BUT MODELS DIFFER ON TIMING AND TRACK OF IT. MODEL DIFFERENCES
INCREASE LATER IN THE WEEK...BUT SOME HINT OF A DRIER PATTERN MAY
BE EMERGING AS SIGNALS FOR STRONGER RIDGING OVER THE GULF ARE
DEVELOPING IN THE MODELS. ENDED UP GOING WITH WPC FOR THE MOST
PART FOR THIS PERIOD...WHICH SHOWS GENERALLY DECREASING POPS THRU
NEXT WEEKEND.

&&

.AVIATION...STRONG LOW LEVEL JET WITH 65 TO 70 KTS OF WIND AT
850MB WILL RESULT IN LOW LEVEL WIND SHEAR OF MUCH OF SOUTHEAST
ALASKA THROUGH LATE MORNING OR EARLY AFTERNOON. MOST SEVERE
CONDITIONS OCCURRING THIS MORNING AND OVER SOUTHERN LOCATIONS.
CEILINGS EXPECTED TO BE MVMC OR BETTER FOR THE MOST PART WITH
LOWEST CONDITIONS DUE TO REDUCTIONS INVISIBILITY IN HEAVY
RAIN/SHOWERS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 10 AM AKDT THIS MORNING FOR AKZ023-027.
MARINE...GALE WARNING FOR PKZ036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>035.

&&

$$

FRITSCH/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK68 PAFC 261331
AFDAFC

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

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

&&

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

&&

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

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

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

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

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

&&

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

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

&&

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

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

&&

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

&&


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

&&

$$

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



000
FXAK68 PAFC 261331
AFDAFC

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

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

&&

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

&&

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

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

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

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

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

&&

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

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

&&

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

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

&&

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

&&


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

&&

$$

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




000
FXAK68 PAFC 261331
AFDAFC

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

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

&&

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

&&

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

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

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

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

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

&&

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

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

&&

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

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

&&

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

&&


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

&&

$$

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




000
FXAK68 PAFC 261331
AFDAFC

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

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

&&

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

&&

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

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

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

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

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

&&

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

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

&&

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

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

&&

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

&&


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

&&

$$

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



000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15



000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK69 PAFG 261254
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
454 AM AKDT SUN APR 26 2015

.DISCUSSION...
MODELS SIMILAR THROUGH ABOUT 36 HOURS BUT THEN BEGIN TO LOOK LIKE
SPAGHETTI AFTER THAT TIME FRAME. LOW IN THE GULF OF ALASKA WILL
CONTINUE TO SPIN AROUND AND WEAKEN THROUGH TUESDAY. OCCLUDED FRONT
FROM GULF LOW WILL MOVE INTO THE SOUTHEASTERN PORTION OF THE
STATE. A PIECE OF ENERGY WILL MOVE NORTH TO THE IMPACT THE EASTERN
INTERIOR TONIGHT AND MON. THERMAL LOW WILL REMAIN OVER EASTERN
INTERIOR AND REMAIN A THREAT FOR SPARKING OFF A FEW THUNDERSTORMS
AND SCATTERED SHOWERS ON MON.

EXTENSIVE FOG OVER THE NORTHERN ACTIC COAST WILL CONTINUE THROUGH
SUN NIGHT. SOME FOG AS LEAKED INTO THE BERING STRAIT. FOG APPEARS
EXTENSIVE ON THE ARCTIC COAST PRESENTLY.

WINDS DO NOT APPEAR TO BE A FACTOR AT ANY LOCATION IN NORTHERN
ALASKA CURRENTLY SO NO WATCHES/WARNINGS OR ADVISORIES HAVE BEEN
ISSUED AND ARE NOT ANTICIPATED AT THIS TIME.

&&

.FIRE WEATHER...VERY DRY CONDITIONS SHOULD CONTINUE THROUGH TODAY
AND RECOVER A BIT TONIGHT AND SUNDAY AS MOISTURE MOVES UP FROM
THE SOUTHEAST.


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

CF APR 15




000
FXAK68 PAFC 260046 CCA
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...

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

&&

.MODEL DISCUSSION...

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

&&

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

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

&&

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

&&

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

&&

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

&&


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

&&

$$

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




000
FXAK68 PAFC 260046 CCA
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...

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

&&

.MODEL DISCUSSION...

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

&&

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

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

&&

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

&&

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

&&

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

&&


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

&&

$$

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



000
FXAK68 PAFC 260046
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...

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

&&

.MODEL DISCUSSION...

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

&&

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

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

&&

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

&&

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

&&

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

&&


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

&&

$$

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



000
FXAK68 PAFC 260046 CCA
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...

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

&&

.MODEL DISCUSSION...

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

&&

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

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

&&

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

&&

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

&&

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

&&


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

&&

$$

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



000
FXAK68 PAFC 260046 CCA
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...

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

&&

.MODEL DISCUSSION...

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

&&

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

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

&&

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

&&

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

&&

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

&&


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

&&

$$

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




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