Area Forecast Discussion
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FXAK67 PAJK 060010
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
406 PM AKDT SUN JUL 5 2015

.SHORT TERM...STRONG UPPER RIDGE WILL REMAIN OVER THE ERN GULF AND
SE AK THRU MON. SFC HIGH PRESSURE WILL REMAIN OVER THE ERN GULF WHILE
AN INVERTED TROF REMAINS OVER THE CENTRAL AND SRN PANHANDLE THRU MON.
USED BLEND OF THE 12Z NAM/EC/GEM FOR PRESSURES...MAINLY TO CAPTURE
THE WEAKER S PRESSURE GRADIENT THAT BECOMES NLY DURING THE NIGHTTIME
BETTER OVER THE NRN INNER CHANNELS AND BETTER PLACEMENT OF
INVERTED TROF.

MAIN FORECAST CONCERNS WILL BE MARINE LAYER...WINDS...AND TEMPS.
GIVEN AMOUNT OF WARMING ALOFT AND STRENGTHENING INVERSION OVER THE
GULF...EXPECT THE LARGE CLEAR AREA OVER THE COASTAL WATERS TO
MOSTLY FILL IN WITH STRATUS AND FOG TONIGHT. THINK THE LOWEST
CLOUDS AND MOST FOG WILL BE OVER THE NE GULF BETWEEN YAKUTAT BAY
AND CAPE EDGECUMBE. THE LOW CLOUDS AND FOG SHOULD EXTEND INTO THE
OUTER COAST LATE THIS EVENING EXCEPT IT WILL REMAIN WELL OFFSHORE
FROM THE SRN COAST. GIVEN SHARPNESS OF THE SFC HIGH AND A MORE NNW
FLOW IN LOWER LEVELS...THE LOW CLOUDS AND FOG SHOULD DISSIPATE BY
AROUND MIDDAY OVER MOST OF THE COASTAL AREA. THE ONLY OTHER CLOUDS
AROUND WILL BE OF THE HIGH VARIETY...BUT THEY LOOK THIN ENOUGH TO
CALL IT MOSTLY CLEAR/SUNNY FOR THE INNER CHANNELS TONIGHT AND SUN.

STRONGEST WINDS WILL BE IN A BAND ALONG AND OFFSHORE THE OUTER
COAST FROM CAPE SPENCER SE TO DIXON ENTRANCE. THE SRN PART OF THIS
AREA WILL SEE WINDS AROUND 25 KT THRU MON...WITH NRN END IN THE
15-20 KT RANGE. INNER CHANNEL WINDS WILL BE PRIMARILY DRIVEN BY
DIURNAL LOCAL EFFECTS ALTHOUGH THE LARGER SCALE PRESSURE GRADIENT
WILL FAVOR NW WINDS. MAY SEE SCA LEVEL WINDS ALONG CROSS SOUND AND
NEAR CAPE DECISION MON AFTERNOON...WITH 15-20 KT WINDS FURTHER
INLAND MON AFTERNOON. LYNN CANAL WILL SEE S WINDS AROUND 15-20 KT
BECOME NLY TO 10 KT OVERNIGHT...THEN COME BACK TO THE S TO 15 KT
IN THE AFTERNOON MON AS SEA BREEZES REDEVELOP.

AS FOR TEMPS...WARM AIR IS OVER THE AREA UNDER THE STRONG
RIDGE...AND WILL GET EVEN WARMER THRU MON. 925 MB TEMPS WILL WARM
TO AROUND 18-22C OVER MOST OF THE INNER CHANNELS AND SRN COAST
MON...WITH 22 TO 25C NEAR HYDER. THIS WILL RESULT IN TEMPS
REACHING WELL INTO THE 70S TO MID 80S FOR MOST INNER CHANNELS
MON...WITH AROUND 90 NEAR HYDER...ABOUT 15-20 DEGREES ABOVE
AVERAGE. THE CENTRAL AND NRN COAST WILL BE HELD IN THE 60S BY W-NW
WINDS OFF THE GULF...ALTHOUGH PORT ALEXANDER WILL LIKELY GET WELL
INTO THE 70S. TONIGHTS MIN TEMPS WILL LIKELY BE CLOSE TO WHAT THEY
WERE THIS MORNING...PERHAPS A FEW DEGREES HIGHER AT MOST IN SOME
AREAS.

.LONG TERM...THE FORECAST FROM MONDAY NIGHT AND BEYOND HAS NOT
CHANGED THAT MUCH FROM PRECEDING SHIFTS. THE BIG STORY CONTINUES
TO BE THE HEAT FOR THE NEAR RANGE AND THEN THE TRANSITION TO MORE
SEASONABLE TEMPERATURES UNDER MAINLY CLOUDY SKIES WITH A CHANCE OF
A LITTLE RAIN STARTING WEDNESDAY AND PERSISTING THROUGH NEXT
WEEKEND FOR THE BULK OF THE PANHANDLE. THIS STORY IS PARAPHRASED
BY THE UPPER AIR PATTERN. THE UPPER LEVEL RIDGE OVER THE EASTERN
GULF AND PANHANDLE MONDAY NIGHT WILL BE PUSHED EASTWARD BY A
SHORTWAVE FROM THE WEST. THUS THE RIDGE IS REPLACED BY MORE
ONSHORE FLOW THROUGH THE WEEKEND.

WHILE THERE IS BROAD CONSENSUS FOR THE UPPER AIR PATTERN THROUGH
FRIDAY...WEAK EMBEDDED SHORT-WAVE FEATURES WILL TAKE TURNS PASSING
THROUGH THE GULF INTO THE PANHANDLE THROUGH NEXT WEEKEND, AND
MODELS CONTINUE TO BARGAIN ON THE WHEN AND WHERE. THE FIRST SUCH
FEATURE APPEARS TO SWING EAST INTO THE NORTHEAST GULF STARTING
TUESDAY AND WILL MOVE OVER THE PANHANDLE BY WEDNESDAY. WHILE MOST
AREAS WILL SEE RAIN CHANCES RISE DURING THIS TIME, CONFIDENCE A
LITTLE HIGHER FOR YAKUTAT AND JUNEAU MAINLY FROM OROGRAPHICS, BUT
AMOUNTS WILL BE LIGHT WITH NO MORE THAN A QUARTER OF AN INCH FOR
MOST LOCATIONS. YAKUTAT MAY SEE A HALF-INCH POSSIBLE THOUGH.
BEYOND THIS TIME FRAME, SOLUTIONS DIFFER, AND THUS THE FORECAST IS
MAINLY BROADBRUSHED.

TEMPERATURES BEGIN TO COOL TUESDAY FROM WEST TO EAST ON CUE WITH
THE RIDGE AXIS AS CLOUDS BEGIN THICKENING FROM ABOVE. FIRST, THE
NORTHERN PANHANDLE COOLS SOMEWHAT ALTHOUGH TEMPERATURES STILL
APPEAR TO RISE TO THE LOWER 70S FOR THE NORTHERN INTERIOR GETTING
COOLER TOWARDS THE COAST. HOWEVER, SOUTHERN AREAS WILL STILL SEE
ANOTHER WARM DAY WITH TEMPERATURES FROM 75 TO LOWER 80S WRANGELL
SOUTH. HYDER WILL ONCE AGAIN BAKE TO 90 AS THE RIDGE AXIS WILL
HAVE JUST PASSED OVERHEAD, SUGGESTING ANY SUBSTANTIAL COOLING WILL
HAVE TO WAIT AWHILE HERE. WE DID COOL TEMPERATURES FOR THE NORTH
ON WEDNESDAY FOR BETTER CHANCES OF RAIN AND MORE PERSISTENT
CLOUD-COVER AND CARRIED THIS TREND THROUGH THE WEEKEND.

MONDAY EVENING THE TAIYA SHOULD REACH BANKFULL WITH SNOWMELT DUE
TO WARM TEMPERATURES. THE POSSIBILITY WILL PERSIST THROUGH TUESDAY
EVENING WITH WATERS LIKELY RECEDING BELOW AFTER THAT. HOWEVER, NO
FLOODING IS EXPECTED AT THIS TIME. WE WILL MONITOR HOW THE STREAM
BEHAVES TONIGHT TO BETTER WRESTLE WITH POTENTIAL MONDAY AND
TUESDAY EVENING.

USED A CHORUS OF MODELS FOR ANY CHANGES...MAINLY ECMWF, GFS, AND
SREF FOR POPS IN THE NEAR-RANGE AND WPC LATER. FORECAST CONFIDENCE
GOOD FOR NEAR-RANGE...AVERAGE THROUGH THE WEEKEND.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ022-041-042.

&&

$$

RWT/JWA

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








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