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000
FXAK68 PAFC 222121
AFDAFC

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

ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE WITH ACCOMPANYING SUBSIDENCE INVERSIONS SETTLED
OVER THE MAINLAND OVERNIGHT. GENERALLY FAIR SKIES WITH LOCALIZED
AREAS OF FOG WERE EVIDENT THIS MORNING ESPECIALLY OVER THE NORTH
GULF COAST. A WEAKENING OCCLUDED FRONT EXTENDED SOUTH ACROSS THE
EASTERN BERING SEA TO WELL SOUTH OF THE AK PEN. THERE WERE SOME
AREAS OF LIGHT RAIN AND GUSTY SOUTHEAST WINDS ASSOCIATED WITH THIS
FEATURE OVER THE AK PEN. DRY CONDITIONS WITH BRISK SOUTH TO EAST
WINDS WERE OBSERVED OVER THE DELTA AND BRISTOL BAY ZONES. A COUPLE
OF WEAK LOWS JUST NORTH OF THE ALEUTIANS WERE PRODUCING RAIN AND
SNOW SHOWERS AND GUSTY WINDS ACROSS THE CHAIN.

MODEL DISCUSSION...
THE GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT AND REASONABLE ON
SYNOPTIC SCALE FEATURES THROUGH THE SHORT TERM. THE GFS AND
ESPECIALLY THE NAM ARE INDICATING INCREASED POTENTIAL FOR
AFTERNOON AND EVENING CONVECTION OVER INTERIOR SW AND SOUTHCENTRAL
ALASKA MID TO LATE THIS WEEK.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
SUBSIDENCE ACROSS SOUTHCENTRAL WILL WEAKEN OVER THE NEXT COUPLE OF
DAYS AS THE UPPER RIDGE MOVES NORTH AND WEST. WESTERLY MOVING SHORT
WAVES COMING OUT OF CANADA AND COOLING TEMPS ALOFT WILL INCREASE
THE INSTABILITY ACROSS THE REGION AND KICK OFF SHOWERS THROUGH
FRI. THUNDERSTORM POTENTIAL EXISTS ALONG THE ALASKA RANGE IN THE
COPPER RIVER BASIN AND TALKEETNA MOUNTAINS. CONDITIONS BECOME
MORE FAVORABLE FOR AFTERNOON AND EVENING CONVECTION THU AND FRI.
COASTAL STRATUS AND FOG LOOKS LIKELY AGAIN TONIGHT AND WED
NIGHT...WITH SOME INTRUSION INTO COOK INLET WITH A WEAK SOUTH
PUSH FROM THE RIDGE IN THE GULF. KODIAK ISLAND WILL HAVE A BREAK
OVER THE NEXT DAY OR SO FROM STEADY RAINS UNTIL NEXT FRONTAL
SYSTEM APPROACHES FROM THE SOUTH ON FRI.

SOUTHWEST ALASKA...
RIDGING OVER SW ALASKA WILL SUPPRESS INTERIOR CONVECTION AND HOLD
THE WEAKENING FRONT OVER THE EASTERN BERING SEA AT BAY KEEPING
COASTAL REGIONS ON THE DRY SIDE THROUGH WED. AFTERNOON AND EVENING
CONVECTION BECOMES MORE PROMISING THU AND FRI AS THE UPPER RIDGE
TRACKS NORTH AND WEAK TRIGGERING WAVES MOVE IN FROM THE EAST.
SO THINKING THAT ISOLATED THUNDERSTORMS BECOME A REAL POSSIBILITY
OVER THE INTERIOR WITH SHOWERS ELSEWHERE.

WINDS ALONG THE COASTAL ZONES SHOULD REMAIN BRISK THROUGH EARLY
WED BEFORE DIMINISHING.

BERING SEA/ALEUTIANS... THE LOW IN THE BERING WILL SPIN
ESSENTIALLY IN PLACE THROUGH WED...WITH SHOWERS AND PATCHY FOG
ACROSS THE ENTIRE REGION...AND GALE FORCE WIND OVER THE WESTERN
ALEUTIANS. WED NIGHT THE NORTH PACIFIC LOW ARRIVES WITH RAIN
SPREADING ALONG THE ALEUTIANS THROUGH FRI. AS THE LOW HEADS INTO
THE GULF OF ALASKA...IMPULSES MOVING AROUND THE NORTHERN FLANK
WILL ALSO KEEP RAIN AND SNOW SHOWERS OVER THE BERING THROUGH THE
END OF THE WEEK.

LONG TERM FORECAST...
THE EC...GFS...AND WPC ARE IN DECENT AGREEMENT THROUGH
SATURDAY...CONTINUING THE EASTWARD MOVEMENT OF THE ALEUTIAN LOW
INTO THE SOUTHERN GULF OF ALASKA. AT THAT POINT AGREEMENT ENDS
WITH COMPLEX SOLUTIONS TO THE GULF LOW...AND EITHER A KAMCHATKA
LOW...OR A RIDGE DOMINATING THE WESTERN BERING. THE FORECAST
UTILIZES THE GFS THROUGH SAT...AND THEN DEFERS TO WPC AND ITS
WIDER ARRAY OF MODELS. THIS MAINTAINS A WEAKENING LOW IN THE
SOUTHERN GULF...AND A KAMCHATKA LOW ON SUN THAT DIVES TO THE
CENTRAL ALEUTIANS BY TUE. THE RESULT IS RAIN ON THE AKPEN AND
KODIAK ISLAND THROUGH THE WEEKEND...WITH WIND AND A MIX OF RAIN
AND SNOW FOR THE WESTERN BERING AND ALEUTIANS EARLY NEXT WEEK. THE
REST OF THE FORECAST AREA WILL BE DRY.
BERING SEA/ALEUTIANS...

AFC WATCHES/WARNINGS/ADVISORIES...

PUBLIC...NONE
MARINE...GALE WARNING 177 178
FIRE WEATHER...NONE

$$

RMC APR 14





000
FXAK68 PAFC 221307
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...
THE WEATHER PATTERN ACROSS MAINLAND ALASKA THIS MORNING CONTINUES
TO BE DOMINATED BY A CLOSED UPPER LEVEL HIGH CENTERED OVER THE
INTERIOR...YIELDING PREDOMINANTLY CLEAR SKIES AND LIGHT WINDS
OVER MUCH OF THE SOUTHERN HALF OF THE STATE. MEANWHILE...PERSISTENT
EASTERLY FLOW OVER THE GULF CONTINUES TO BRING LIGHT RAIN AND LOW
STRATUS/FOG TO KODIAK ISLAND. FURTHER WEST...A LARGE VERTICALLY
STACKED LOW CENTERED JUST NORTH OF THE CENTRAL ALEUTIAN CHAIN
ENCOMPASSES MUCH OF THE BERING SEA...KEEPING GENERALLY SHOWERY
WEATHER OVER THE REGION. A WEAKENING FRONT EXTENDS EASTWARD
ACROSS THE CENTRAL AND EASTERN BERING...SPREADING A MIX OF RAIN
AND SNOW ALONG WITH GUSTY SOUTHEASTERLY WINDS FROM THE PRIBILOF
ISLANDS TO THE EASTERN ALEUTIANS AND ALASKA PENINSULA.

&&

.MODEL DISCUSSION...
MODELS CONTINUE TO SHOW GOOD AGREEMENT WITH RESPECT TO THE
THE OVERALL SYNOPTIC PATTERN IN THE SHORT TERM...WITH ALL
GUIDANCE POINTING TOWARDS A SIMILAR EVOLUTION FOR THE MAIN
FEATURES OVER THE NEXT SEVERAL DAYS AS THE UPPER HIGH OVER THE
MAINLAND BEGINS TO BREAK DOWN AND THE BERING LOW CONTINUES TO
GRADUALLY WEAKEN. MAINLY UTILIZED A GFS/EC SOLUTION FOR THE
FORECAST...WITH A SLIGHT PREFERENCE TOWARDS THE GFS LATER IN THE
WEEK AS THE NEXT LOW APPROACHES THE ALEUTIAN CHAIN.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
ANOTHER DAY OF MOSTLY SUNNY SKIES AND ABOVE NORMAL TEMPERATURES IS
IN STORE FOR SOUTHCENTRAL AS HIGH PRESSURE REMAINS IN CONTROL
THROUGH THIS EVENING. THE UPPER HIGH WILL THEN BEGIN TO WEAKEN
AND MOVE OFF TO THE NORTHWEST TONIGHT...ALLOWING AN UPPER WAVE TO
APPROACH THE AREA FROM THE YUKON TERRITORY. THIS WILL YIELD AN
INCREASE IN CLOUD COVER FOR WEDNESDAY AND THURSDAY AS WELL AS THE
CHANCE FOR SOME AFTERNOON SHOWERS ALONG THE MOUNTAINS AS
TEMPERATURES COOL ALOFT AND CONDITIONS BECOME A LITTLE MORE
UNSTABLE. LOCAL WINDS WILL CONTINUE TO BE DRIVEN MAINLY BY DIURNAL
PROCESSES...WITH THE TYPICAL AFTERNOON SEA BREEZES AND NIGHTTIME
DRAINAGE WINDS IN FAVORED AREAS.

SOUTHWEST ALASKA...
HIGH PRESSURE OVER INTERIOR ALASKA WILL KEEP MOST OF THE
SOUTHWEST DRY...ALTHOUGH SOME SHOWERS ASSOCIATED WITH THE BERING
LOW WILL AFFECT THE AKPEN AND WESTERN CAPES THROUGH WED. ON THU THE
ARRIVAL OF THE NORTH PACIFIC LOW WILL PUSH THE SHOWER ACTIVITY A
BIT FURTHER INLAND INTO THE BRISTOL BAY ZONE...WITH SOME SHOWERS
REACHING INTO THE KUSKOKWIM VALLEY AND DELTA ON FRI.

BERING SEA/ALEUTIANS...
THE LOW IN THE BERING WILL SPIN ESSENTIALLY IN PLACE THROUGH
WED...WITH SHOWERS AND PATCHY FOG ACROSS THE ENTIRE REGION...AND
GALE FORCE WIND OVER THE WESTERN ALEUTIANS. WED NIGHT THE NORTH
PACIFIC LOW ARRIVES WITH RAIN SPREADING ALONG THE ALEUTIANS
THROUGH FRI. AS THE LOW HEADS INTO THE GULF OF ALASKA IMPULSES
MOVING AROUND THE NORTHERN FLANK WILL ALSO KEEP RAIN AND SNOW
SHOWERS OVER THE BERING THROUGH THE END OF THE WEEK.

&&

.LONG TERM FORECAST...
THE EC...GFS...AND WPC ARE IN DECENT AGREEMENT THROUGH
SATURDAY...CONTINUING THE EASTWARD MOVEMENT OF THE ALEUTIAN LOW
INTO THE SOUTHERN GULF OF ALASKA. AT THAT POINT AGREEMENT ENDS
WITH COMPLEX SOLUTIONS TO THE GULF LOW...AND EITHER A KAMCHATKA
LOW...OR A RIDGE DOMINATING THE WESTERN BERING. THE FORECAST
UTILIZES THE GFS THROUGH SAT...AND THEN DEFERS TO WPC AND ITS
WIDER ARRAY OF MODELS. THIS MAINTAINS A WEAKENING LOW IN THE
SOUTHERN GULF...AND A KAMCHATKA LOW ON SUN THAT DIVES TO THE
CENTRAL ALEUTIANS BY TUE. THE RESULT IS RAIN ON THE AKPEN AND
KODIAK ISLAND THROUGH THE WEEKEND...WITH WIND AND A MIX OF RAIN
AND SNOW FOR THE WESTERN BERING AND ALEUTIANS EARLY NEXT WEEK. THE
REST OF THE FORECAST AREA WILL BE DRY.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 176 177 178
FIRE WEATHER...NONE

&&

$$

CB/DS APR 14





000
FXAK68 PAFC 220030
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...
A UPPER RIDGE AND ASSOCIATED SURFACE REFLECTION BROUGHT GENERALLY
FAIR SKIES TO SOUTHCENTRAL ALASKA. GUSTY GAP FLOWS WERE PRESENT
ALONG THE NORTH GULF AND OVER THE WESTERN AND NORTHERN PRINCE
WILLIAM SOUND. EASTERLY FLOW CONTINUED LIGHT RAIN AND DRIZZLE WITH
SOME FOG OVER KODIAK ISLAND.

OUT WEST A 970S LOW COMPLEX OVER THE CENTRAL ALEUTIANS WAS QUASI-
STATIONARY AND SLOWLY WEAKENING. THE ASSOCIATED OCCLUDED FRONT
EXTENDED FROM THE WESTERN BERING SEA...EAST ACROSS THE NORTHERN
BERING TO OVER THE EASTERN ALEUTIANS. GALE FORCE EAST TO SE WINDS
WERE EVIDENT ALONG AND JUST AHEAD OF THIS BOUNDARY. FELL WAS
EVIDENT ALONG THE SOUTHERN END OF THE BOUNDARY NEAR THE EASTERN
ALEUTIANS WITH SNOW OR A MIX NEAR THE PRIBILOFS. STRATUS AND FOG
WAS EVIDENT OVER THE SOUTHWEST MAINLAND ALONG THE BRISTOL BAY
COAST AND DELTA.

.MODEL DISCUSSION...
THE MODELS ARE GENERALLY IN GOOD AGREEMENT AND REASONABLE ON THE
SYNOPTIC FEATURES IN THE EAST. OUT WEST...HAVE SIMILAR HANDLING OF
THE LOW COMPLEX OVER THE ALEUTIANS AND ITS ASSOCIATED FRONT. THE
NEXT COMPLEX TO APPROACH SOUTH OF THE ALEUTIANS ON THURSDAY APPEAR
TO BE BEST HANDLED BY THE GFS/EC.

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
THE UPPER RIDGE SLOWLY WEAKENS AND STARTS TO SHIFT NORTH AND WEST
TUE NIGHT. THE RIDGE CONTINUES TO RETREAT THROUGH THURSDAY AS
WAVES MOVES WEST OUT OF CANADA TO ACROSS SOUTHCENTRAL. THIS
PATTERN TO BRING INCREASED CLOUD COVER AND CHANCES OF SHOWERS.
CONDITIONS BECOME SOMEWHAT MORE UNSTABLE ON THURSDAY WITH MODERATE
COOLING OF TEMPERATURES ALOFT. STABILITY INDICES WOULD SUPPORT
ISOLATED THUNDERSTORMS. HOWEVER...ADDITIONAL CLOUD COVER COULD
INHIBIT SURFACE HEATING AND DETRACT FROM THUNDERSTORM POTENTIAL.

SOUTHWEST ALASKA...
SCATTERED SHOWERS OVER THE LOWER KUSKOKWIM DELTA WILL TAPER OFF
THIS EVENING AS THE UPPER LEVEL SHORTWAVE OVER THE AREA TRACKS
FURTHER NORTH AND WEAKENS. SKIES WILL BEGIN TO CLEAR OVER THE
SOUTHWEST MAINLAND THIS EVENING AS THE MID LEVEL RIDGE OVER THE
INTERIOR WORKS ITS WAY WESTWARD...AND THE FLOW BECOMES MORE
OFFSHORE IN ADVANCE OF THE FRONT OVER THE BERING SEA. THIS FRONT
WILL BRING RAIN AND GUSTY SOUTHEASTERLY WINDS TO COASTAL BRISTOL
BAY TUESDAY/WEDNESDAY. INTERIOR LOCATIONS WILL OTHERWISE REMAIN
UNDER THE INFLUENCE OF THE MID LEVEL RIDGE AND EXPERIENCE MOSTLY
CLEAR SKIES WITH TEMPERATURES NEAR TO ABOVE NORMAL.

BERING SEA/ALEUTIANS...
THE ALEUTIAN LOW AND ITS ASSOCIATED FRONT WILL BE THE MAIN DRIVER
OF THE WEATHER THROUGH THE SHORT TERM. THE FRONTAL SYSTEM WILL
CONTINUE TO PRODUCE GUSTY WINDS AND PRECIPITATION OVER THE
PRIBILOFS AND AKPEN THROUGH TUESDAY. THE FRONT WILL THEN DISSIPATE
OVER THE SOUTHWEST COAST WED MORNING...THE UPPER TROUGH WILL
REMAIN OVER THE SOUTHERN BERING THROUGH MID WEEK LEAVING THE
REGION CLOUDY WITH A CHANCE OF RAIN AND SNOW SHOWERS.

.LONG TERM FORECAST...
THE MODELS ARE BEGINNING TO COME TO A CONSENSUS THAT THE NEXT
ALEUTIAN LOW WILL STRUGGLE TO REACH INTO THE EXTREME SOUTHERN GULF
OF ALASKA THIS WEEKEND...MOST LIKELY KEEPING MUCH OF THE INTERIOR
SOUTHERN MAINLAND DRY AND MOSTLY CLEAR. THE GULF COAST ON THE
OTHER HAND WILL SEE ANOTHER ROUND OF RAIN THIS WEEKEND AS THE LOW
APPROACHES THE SOUTHERN GULF. THE ONE CAVEAT TO THIS IS WITH A
POSSIBILITY THAT THE THERMAL TROUGH WILL MAKE ITS FIRST APPEARANCE
OF THE SEASON LATE THIS WEEK OR THIS WEEKEND. THIS WOULD BRING IN
A CHANCE OF DIURNAL SHOWERS ALONG THE MOUNTAINS...BUT OTHERWISE
DRY AND WITH TEMPERATURES ABOVE NORMAL.

AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 170 172 173 176 177 178
FIRE WEATHER...NONE

$$


RMC/TP APR 14





000
FXAK68 PAFC 211323
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
523 AM AKDT MON APR 21 2014

.ANALYSIS AND UPPER LEVELS...
HIGH PRESSURE CENTERED OVER THE INTERIOR CONTINUES TO SUPPORT
BENIGN CONDITIONS ACROSS MUCH OF MAINLAND ALASKA THIS
MORNING...WITH MAINLY JUST SOME SCATTERED MID LEVEL CLOUDS OVER
THE SOUTHERN MAINLAND. A LOW OVER THE FAR SOUTHERN GULF IS
GRADUALLY WEAKENING AS IT MOVES AWAY FROM THE AREA AND INTO THE
NORTHEASTERN PACIFIC...ALTHOUGH A WEAK WAVE ROTATING AROUND ITS
NORTHERN PERIPHERY CONTINUES TO BRING A FEW RAIN SHOWERS TO KODIAK
ISLAND. OUT WEST...A BROAD LOW PRESSURE SYSTEM IS CENTERED OVER
THE WESTERN ALEUTIANS AS AN ASSOCIATED FRONT PUSHES INTO THE
CENTRAL BERING ACCOMPANIED BY A WIDE SWATH OF PRECIPITATION AND
GALE FORCE WINDS.

&&

.MODEL DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE SHORT TERM WITH
RESPECT TO THE OVERALL SYNOPTIC PATTERN. THE LOW CURRENTLY OVER
THE WESTERN ALEUTIANS WILL GRADUALLY WEAKEN THROUGH THE EARLY PART
OF THE WEEK AS IT MOVES EASTWARD TO THE CENTRAL BERING...WITH THE
ASSOCIATED FRONT STALLING OUT AND EVENTUALLY DISSIPATING ACROSS
THE AKPEN AND SOUTHERN GULF AS IT ENCOUNTERS THE RIDGE OVER THE
MAINLAND. THIS WILL HELP TO KEEP THE BULK OF THE PRECIPITATION
CONFINED TO THE BERING AND SOUTHERN GULF THROUGH THE END OF WEEK.

&&

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
PLEASANT CONDITIONS MARKED BY ABUNDANT SUNSHINE AND ABOVE NORMAL
TEMPERATURES WILL CONTINUE THROUGH THE MIDDLE OF THE WEEK AS HIGH
PRESSURE REMAINS IN CONTROL OVER THE MAINLAND. AS MENTIONED
ABOVE...THIS WILL KEEP THE BULK OF THE PRECIPITATION CONFINED TO
KODIAK ISLAND AS THE BERING FRONT STALLS AND WEAKENS OVER THE
SOUTHERN GULF. A RELATIVELY WEAK PRESSURE GRADIENT WILL ALLOW
WINDS TO BE DRIVEN MAINLY BY DIURNAL PROCESSES FOR THE NEXT
SEVERAL DAYS.

SOUTHWEST ALASKA...
THE ISOLATED SNOW AND RAIN SHOWERS FORMING ALONG THE WEAK UPPER
LEVEL TROUGH WILL CONTINUE SPREADING NORTHWARD THROUGH THE
KUSKOKWIM DELTA AND WESTERN BRISTOL BAY TODAY. THESE SHOWERS WILL
THEN DISSIPATE LATE THIS AFTERNOON AS THE ASSOCIATED SHORTWAVE
SIGNIFICANTLY FLATTENS OUT AND THE TROUGH LIFTS NORTHWARD. BEHIND
THESE SHOWERS...PATCHY FOG AND LOW STRATUS CLOUDS HAVE DEVELOPED
ALONG THE SOUTHERN BRISTOL BAY COAST THAT WILL CONTINUE THIS
MORNING WITH WEAK ONSHORE FLOW. CLOUDS WILL THEN BEGIN TO CLEAR
OUT THIS EVENING AS THE MID LEVEL RIDGE OVER THE INTERIOR WORKS
ITS WAY WESTWARD...AND THE FLOW BECOMES MORE OFFSHORE IN ADVANCE
OF THE FRONT OVER THE BERING SEA. THIS FRONT WILL BRING RAIN AND
GUSTY SOUTHEASTERLY WINDS TO COASTAL BRISTOL BAY
TUESDAY/WEDNESDAY. INTERIOR LOCATIONS WILL OTHERWISE REMAIN UNDER
THE INFLUENCE OF THE MID LEVEL RIDGE AND EXPERIENCE MOSTLY CLEAR
SKIES WITH TEMPERATURES NEAR TO ABOVE NORMAL.

BERING SEA/ALEUTIANS...
THE ALEUTIAN LOW AND ITS ASSOCIATED FRONT WILL
BE THE MAIN DRIVER OF THE WEATHER OVER THE NEXT 48 HOURS. THE
WEAKENING FRONT WILL STILL HAVE ENOUGH PUNCH LEFT IN IT TO BRING
STRONG WINDS TO THE DUTCH HARBOR AREA TODAY...AND GUSTY WINDS TO
THE PRIBILOFS AND AKPEN THROUGH TUESDAY. PRECIPITATION WILL
INITIALLY START AS A RAIN/SNOW MIX WITH THE FRONT BUT WILL SWITCH
OVER TO JUST RAIN AFTER A FEW HOURS...SO ANY SNOW ACCUMULATION
WILL BE MINIMAL. WHILE THE FRONT WILL DISSIPATE OVER THE SOUTHWEST
COAST LATE TUESDAY...THE UPPER TROUGH WILL REMAIN OVER THE
SOUTHERN BERING THROUGH MID WEEK LEAVING THE REGION CLOUDY WITH A
CHANCE OF RAIN AND SNOW SHOWERS.

&&

.LONG TERM FORECAST...
THE MODELS ARE BEGINNING TO COME TO A CONSENSUS THAT THE NEXT
ALEUTIAN LOW WILL STRUGGLE TO REACH INTO THE EXTREME SOUTHERN GULF
OF ALASKA THIS WEEKEND...MOST LIKELY KEEPING MUCH OF THE INTERIOR
SOUTHERN MAINLAND DRY AND MOSTLY CLEAR. THE GULF COAST ON THE
OTHER HAND WILL SEE ANOTHER ROUND OF RAIN THIS WEEKEND AS THE LOW
APPROACHES THE SOUTHERN GULF. THE ONE CAVEAT TO THIS IS WITH A
POSSIBILITY THAT THE THERMAL TROUGH WILL MAKE ITS FIRST APPEARANCE
OF THE SEASON LATE THIS WEEK OR THIS WEEKEND. THIS WOULD BRING IN
A CHANCE OF DIURNAL SHOWERS ALONG THE MOUNTAINS...BUT OTHERWISE
DRY AND WITH TEMPERATURES ABOVE NORMAL.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 170 172 173 176 177 178
FIRE WEATHER...NONE

&&

$$

CB/DEK APR 14





000
FXAK68 PAFC 202146
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...
A LOW OVER THE NORTH GULF AND ASSOCIATED FRONTAL SYSTEM IS PRODUCING
GALE FORCE EAST/NE WINDS AND RAIN ACROSS THE NORTHERN GULF. A FEW
SHOWERS ARE SPREADING INLAND ACROSS THE KENAI PENINSULA AS WELL AS
OVER THE SOUTHERN COPPER RIVER BASIN. A STACKED LOW CENTER SW OF
THE ALEUTIANS IS MOVING NORTH TOWARD THE CENTRAL ALEUTIANS. THE
ASSOCIATED FRONTAL SYSTEM TO THE NORTH IS SPREADING GALE FORCE
EASTERLY WINDS AND RAIN/SNOW OVER THE CENTRAL AND WESTERN
ALEUTIANS.

&&

.MODEL DISCUSSION...
MODELS IN GENERAL ARE IN FAIRLY GOOD AGREEMENT AND REASONABLE.
SOME MINOR DIFFERENCES EXIST IN POSITIONING AND TIMING OF THE
FRONTAL SYSTEM AS IT MOVES EAST ACROSS THE ALEUTIANS/AK PEN. THE
ECMWF/GFS WILL BE GENERALLY USED IN THE WEST. THE HIGHER RES GEM
REG AND NAM PROVIDE THE BEST DETAIL ON GAP FLOWS ACROSS
SOUTHCENTRAL TODAY/EVE...OTHERWISE RELATIVELY MINOR SYNOPTIC
SCALE DIFFERENCES IN MODELS THROUGH THE SHORT TERM IN THE EAST.

&&

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA...
THE WEAKENING 980S STACKED LOW OVER THE SW GULF CONTINUES MOVES
SE AND WEAKENS. A SECONDARY LOW OVER THE CENTRAL GULF MOVES WEST
TODAY THEN SOUTH TONIGHT/MON AND SLOWLY WEAKENS. ITS ASSOCIATED
FRONTAL THROUGH WEAKENS AS IT MOVES WEST ACROSS THE NORTHERN GULF
TONIGHT. STRONG EAST/NE WINDS SPREAD WEST ACROSS THE GULF THROUGH
THIS AFTERNOON THEN WEAKEN TONIGHT/MON AS THE LOW CENTRAL TRACKS
SOUTH. PRESSURE RISES OVER THE NORTH GULF COAST AND PRESSURE
FALLS DUE TO HEATING OVER THE SUSITNA VALLEY WILL PRODUCE BRISK
GAP FLOWS ACROSS TURNAGAIN ARM AND THE KNIK RIVER VALLEY THIS
AFTERNOON AND EVENING. WINDS SHOULD DIMINISH AGAIN LATE THIS
EVENING AS GRADIENTS RELAX. AFTER TODAY NOCTURNAL (DRAINAGE) AND
DIURNAL(SEA BREEZES) WILL BE THE DOMINATE FLOW PATTERNS THROUGH
EARLY THIS WEEK. THE ORGANIZED PRECIPITATION ASSOCIATED WITH THE
FRONT MOVING ACROSS THE GULF TODAY WILL GIVE WAY TO SOMEWHAT DRIER
CONDITIONS ACROSS THE NORTH GULF AND WEAK AFTERNOON AND EVENING
CONVECTION INLAND THROUGH MID WEEK. A WEAKENING FRONT SYSTEM
MOVING ACROSS THE ALEUTIANS MAY BRING SOME LIGHT RAIN TO KODIAK ON
WED.

SOUTHWEST ALASKA...RIDGING OVER THE NORTHERN MAINLAND WHICH HAS
BROUGHT A BRIEF CLEARING TO THE SOUTHWEST MAINLAND TODAY WILL BE
FORCED BACK EAST BY AN UPPER LEVEL WAVE FROM THE WEST TOMORROW
MORNING. THE WAVE WILL MOVE THROUGH THE AREA AND RAPIDLY DISSIPATE
BY TOMORROW AFTERNOON...BRINGING SCATTERED SHOWERS TO THE LOWER
KUSKOKWIM DELTA AND A CHANCE OF PRECIPITATION TO THE BRISTOL BAY
AREA. A FRONTAL SYSTEM ASSOCIATED WITH AN ALEUTIAN LOW WILL PUSH
INTO THE SOUTHWESTERN COAST TUESDAY MORNING...PRODUCING WETTER AND
WINDIER CONDITIONS ALONG THE AK PEN AND WESTERN COAST THROUGH
TUESDAY AFTERNOON.

BERING SEA/ALEUTIANS...THE STRONG NORTH PACIFIC LOW SOUTH OF
SHEMYA...CURRENTLY PRODUCING STRONG EAST WINDS AND SNOW/RAIN OVER
THE WESTERN ALEUTIANS WILL TRACK OVER THE WESTERN ALEUTIANS
TOMORROW MORNING. THE LOW WILL THEN STALL OUT AND SLOWLY DISSIPATE
OVER THE CENTRAL ALEUTIANS ON TUESDAY...WHICH WILL BRING CLOUDS
AND WIDESPREAD PRECIPITATION TO THE ENTIRE REGION THROUGH MID
WEEK. AN ASSOCIATED STRONG FRONT WILL MOVE OVER THE CENTRAL
ALEUTIANS THIS EVENING...BRINGING WIDESPREAD RAINS AND STRONG WIND
GUSTS TO THE CENTRAL ALEUTIANS. THE FRONT WILL THEN QUICKLY PUSH
INTO THE EASTERN ALEUTIANS AND PRIBILOFS BY MONDAY
MORNING...BEFORE DIMINISHING CONSIDERABLY IN INTENSITY ON MONDAY
EVENING AS IT TRACKS INLAND.

&&

.LONG TERM FORECAST...
WHILE THERE HAS NOT BEEN A LARGE CHANGE IN THE LONG TERM
FORECAST...THE MODELS ARE BEGINNING TO STRUGGLE LATE THIS WEEK
WITH THE TRACK OF THE NEXT LOW THROUGH THE ALEUTIANS. THE GENERAL
PATTERN OF RIDGING OVER MOST OF THE MAINLAND AND LOWS OVER THE
BERING OR NORTH PACIFIC WILL REMAIN MOSTLY IN TACT...BUT THE DEVIL
STILL REMAINS IN THE DETAILS. THE MODELS ARE STRUGGLING WITH HOW
FAR NORTH INTO THE PACIFIC THAT THE MAINLAND RIDGE WILL ALLOW AN
ALEUTIAN LOW TO TRAVEL THIS WEEKEND...SO RAIN FOR THE GULF COAST
CANNOT BE RULED OUT THIS WEEKEND. IT DOES STILL APPEAR THAT THE
INTERIOR SOUTHERN MAINLAND WILL REMAIN MOSTLY CLEAR AND DRY FOR
THE NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 119 120 131 132 155 170 172 173 174 175 176 177 178
              351 411 412 413.
FIRE WEATHER...NONE.

&&

$$

RMC APR 14





000
FXAK68 PAFC 201322
AFDAFC

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

.ANALYSIS AND UPPER LEVELS...
SKIES CONTINUE TO CLEAR ACROSS MUCH OF THE SOUTHERN MAINLAND THIS
MORNING AS HIGH PRESSURE BUILDS OVER THE INTERIOR...WHILE A BROAD
AREA OF LOW PRESSURE CENTERED OVER THE SOUTHERN GULF CONTINUES TO
BRING STEADY RAIN TO KODIAK ISLAND. A TROUGH EXTENDING
NORTHWESTWARD FROM THE LOW INTO THE EASTERN BERING IS SUPPORTING
A MIX OF RAIN AND SNOW SHOWERS FROM THE ALASKA PENINSULA TO THE
EASTERN ALEUTIANS. FURTHER WEST...ANOTHER RIDGE IS BUILDING OVER
THE CENTRAL BERING AHEAD OF A STRONG NORTH PACIFIC LOW AND
ASSOCIATED FRONT APPROACHING THE WESTERN ALEUTIANS ACCOMPANIED BY
A WIDE SWATH OF PRECIPITATION AND GALE FORCE WINDS.

&&

.MODEL DISCUSSION...
MODELS REMAIN IN GOOD OVERALL SYNOPTIC AGREEMENT THROUGH THE
SHORT TERM AND HAVE ALSO COME INTO BETTER AGREEMENT WITH RESPECT
TO THE STRENGTH/TIMING OF VARIOUS WAVES ROTATING AROUND THE
NORTHERN PERIPHERY OF THE GULF LOW LATER THIS AFTERNOON. THE LOW
WILL GRADUALLY WEAKEN THROUGH MONDAY AS IT TRACKS TOWARDS THE
SOUTHEAST AND HIGH PRESSURE BECOMES BETTER ESTABLISHED OVER THE
MAINLAND. MEANWHILE...THE NORTH PACIFIC LOW APPROACHING THE
WESTERN ALEUTIANS WILL TRACK ALONG THE CHAIN THROUGH THE MIDDLE OF
THE WEEK BUT LIKELY REMAIN SOUTH OF THE MAINLAND AS IT ENCOUNTERS
THE BLOCKING HIGH CENTERED OVER THE INTERIOR. CONTINUED TO UTILIZE
THE EC GIVEN ITS CONSISTENCY OVER THE PAST SEVERAL DAYS.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
RAIN ASSOCIATED WITH THE GULF LOW WILL REMAIN CONFINED MOSTLY TO
KODIAK ISLAND AND THE GULF WATERS...WITH PRECIPITATION TRENDING
DOWNWARD THROUGH MONDAY AS THE LOW SINKS SLOWLY SOUTHWARD AWAY
FROM THE AREA. A WEAK DISTURBANCE ROTATING THROUGH THE NORTHERN
GULF THIS AFTERNOON ON THE NORTHERN PERIPHERY OF THE LOW WILL
PROVIDE THE CHANCE FOR A FEW RAIN SHOWERS ALONG THE COAST AND ALSO
SERVE TO INCREASE GAP WINDS THROUGH FAVORABLE AREAS SUCH AS
TURNAGAIN ARM AND THE KNIK RIVER VALLEY. OTHERWISE...MAINLY DRY
CONDITIONS MARKED BY ABUNDANT SUNSHINE WILL PREVAIL ACROSS MUCH OF
THE AREA THROUGH THE EARLY PART OF THE WEEK AS HIGH PRESSURE
BECOMES BETTER ESTABLISHED OVER THE MAINLAND. WILL HAVE TO MONITOR
FIRE WEATHER POTENTIAL THROUGH THE MATANUSKA VALLEY THIS AFTERNOON
AS GUSTY KNIK WINDS COUPLED WITH LOW RELATIVE HUMIDITY VALUES
COULD LEAD TO CONDITIONS APPROACHING RED FLAG CRITERIA.

SOUTHWEST ALASKA...
THE REGION WILL SEE GRADUALLY CLEARING SKIES
THROUGHOUT THE DAY TODAY AS RIDGING OVER THE NORTHERN MAINLAND
CONTINUES TO BUILD SOUTHWARD. FURTHER SOUTH...RAIN SHOWERS ALONG
THE AKPEN WILL DISSIPATE THIS MORNING AND SKIES WILL BRIEFLY
CLEAR UNTIL A FRONT FROM THE ALEUTIAN LOW APPROACHES ON TUESDAY.
THERE IS BETTER AGREEMENT IN THE MODELS NOW THAT THIS FRONT WILL
STRUGGLE TO REACH VERY FAR INLAND...MEANING THAT INTERIOR
LOCATIONS OF BRISTOL BAY AND THE KUSKOKWIM DELTA WILL LIKELY STILL
SEE PARTLY CLOUDY SKIES AND ABOVE NORMAL TEMPERATURES INTO MID
WEEK. AHEAD OF THE ALEUTIAN LOW...A WEAK UPPER TROUGH CURRENTLY
OVER THE CENTRAL BERING WILL MIGRATE TOWARDS THE KUSKOKWIM DELTA
AND BRING A SLIGHT CHANCE OF RAIN AND SNOW SHOWERS TO THE AREA
OVERNIGHT TONIGHT.

BERING SEA/ALEUTIANS...
CONDITIONS THROUGHOUT THE WESTERN AND
CENTRAL ALEUTIANS WILL QUICKLY DETERIORATE OVER THE COURSE OF
THIS MORNING AS THE FRONT AHEAD OF THE ALEUTIAN LOW APPROACHES.
THE STRONG GALE FORCE FRONT THAT ACCOMPANIES THIS LOW WILL BRING
WIDESPREAD RAINS AND STRONG WIND GUSTS TO THE WESTERN AND CENTRAL
ALEUTIANS TODAY. THIS FRONT WILL REACH THE PRIBILOFS AND AKPEN ON
MONDAY MORNING BEFORE DIMINISHING CONSIDERABLY IN INTENSITY ON
MONDAY AFTERNOON. THE ENTIRE SYSTEM WILL THEN STALL OUT AND SLOWLY
DISSIPATE OVER THE CENTRAL BERING AND ALEUTIANS ON TUESDAY...WHICH
WILL BRING CLOUDS AND RAIN TO THE ENTIRE REGION THROUGH MID WEEK.

&&

.LONG TERM FORECAST...
WHILE THERE HAS NOT BEEN A LARGE CHANGE IN THE LONG TERM
FORECAST...THE MODELS ARE BEGINNING TO STRUGGLE LATE THIS WEEK
WITH THE TRACK OF THE NEXT LOW THROUGH THE ALEUTIANS. THE GENERAL
PATTERN OF RIDGING OVER MOST OF THE MAINLAND AND LOWS OVER THE
BERING OR NORTH PACIFIC WILL REMAIN MOSTLY INTACT...BUT THE DEVIL
STILL REMAINS IN THE DETAILS. THE MODELS ARE STRUGGLING WITH HOW
FAR NORTH INTO THE PACIFIC THAT THE MAINLAND RIDGE WILL ALLOW AN
ALEUTIAN LOW TO TRAVEL THIS WEEKEND...SO RAIN FOR THE GULF COAST
CANNOT BE RULED OUT THIS WEEKEND. IT DOES STILL APPEAR THAT THE
INTERIOR SOUTHERN MAINLAND WILL REMAIN MOSTLY CLEAR AND DRY FOR
THE NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 119 120 131 132 155 170 172 173 174 175 176
  177 178
FIRE WEATHER...NONE

&&

$$

CB/DEK APR 14





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