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FXAK67 PAJK 250013
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
313 PM AKST WED DEC 24 2014

.SHORT TERM...SCATTERED SHOWERS HAVE PUSHED INTO THE PANHANDLE
WITHIN A BAND OF WEAK COLD AIR ADVECTION MOVING IN WITH THE
SURFACE RIDGE. BEHIND IT AN OCCLUSION OVER THE CENTRAL GULF IS
SENDING A SWATH OF STRATIFORM PRECIPITATION INTO THE EASTERN
GULF. WITH SHALLOW COLD AIR NOW IN PLACE OVER THE PANHANDLE AND
SOME STRONGER COLD AIR ADVECTION SLIDING SOUTHEAST FROM THE YUKON
OVER THE FAR NORTHERN PANHANDLE...THIS OCCLUSION WILL COME BEARING
GIFTS OF SNOW FLAKES FROM YAKUTAT SOUTH TO THE ICY STRAIT CORRIDOR
AND ON TO PETERSBURG AND HYDER LATE. FOR THE KIDS OF SITKA,
WRANGELL, PRINCE OF WALES, AND THE SOUTHERN INNER CHANNELS THE
PRECIPITATION WILL BEGIN AND REMAIN RAIN OVERNIGHT...BUT LUCKILY
SANTA`S SLEIGH IS BUILT FOR RAIN, TOO.

SNOWFALL ACCUMULATIONS BETWEEN 1 AND 3 INCHES WILL FALL OVER THE
PANHANDLE...THE GREATEST RATES DEVELOPING AROUND OR AFTER MIDNIGHT
FROM YAKUTAT DOWN TO CROSS SOUND, AND IN THE EARLY MORNING HOURS
INLAND TO GUSTAVUS/HOONAH. JUNEAU SHOULD SEE THE FASTEST SNOWFALL
RATE BETWEEN 4 AND 8 AM...SO THEREFORE, WE ONLY HAVE 1 INCH
ACCUMULATION TONIGHT WITH ANOTHER 2 INCHES FOR CHRISTMAS MORNING,
BASICALLY WHEN KIDS WILL BE WAKING ADULTS. THE TRANSITION TO RAIN
SHOULD SHORTLY FOLLOW THE MAXIMUM RATES, AS THE MAXIMUM LIFT IN
THE ATMOSPHERE WILL CORRESPOND WILL LIE JUST AHEAD OF THE FRONT.

ALTHOUGH TEMPERATURES WARMED ABOVE FREEZING IN MOST OF THE
PANHANDLE, THEY SHOULD DECREASE TO THEIR MINIMA THIS EVENING, MUCH
MILDER THAN THIS MORNING AND REMAIN STEADY OVERNIGHT OR SLOWLY RISE.
TEMPERATURES WILL RISE EVEN FASTER ON THURSDAY AS THE FRONT LIFTS
THROUGH THE REGION. WE DID RAISE HIGHS JUST A TAD FOR THURSDAY,
ALTHOUGH SOME MODELS SUGGESTING LOW 40S FOR MANY AREAS...
INCLUDING JUNEAU. KIDS WHO WANT TO PLAY IN THE SNOW SHOULD NOT
TARRY TOO LONG INDOORS. ANY CHANGE TO RAIN FOR LATE THURSDAY
AFTERNOON IS SKETCHIER NEAR LYNN CANAL. HIGH RES BUILDING A
SOUTHERLY SURGE THROUGH HERE, AND WITH IT THE TEMPERATURE SHOULD
SPIKE. BUT DID INCLUDE IT FOR SKAGWAY, ALTHOUGH ALLOWED HAINES TO
REMAIN SNOW.

WINDS SHOULD NOT BE A BIG ISSUE, ALTHOUGH A WEAK SCA BARRIER JET
WILL DEVELOP OVERNIGHT IN ZONE 52 AND WESTERLIES SHOULD RISE TO 25
KT BEHIND A SECOND WAVE PASSING THROUGH THE EASTERN GULF ON
THURSDAY. SEAS WILL RISE OVERNIGHT, PARTICULARLY IN THE SOUTHERLY
AND SOUTHWESTERLY FLOW BEHIND THE FRONT.

LEANED ON THE ARW, NMM, ECMWF, AND NAM FOR SOME SMALL MINOR SHIFTS
IN THE FORECAST. BUT LITTLE HAS CHANGED.

.LONG TERM...LONG RANGE TODAY FEATURE A PATTERN CHANGE ALOFT AS
WE GO FROM A EAST/WEST UPPER FLOW PATTERN WITH A SLIGHT RIDGE OVER
THE NORTHEAST PACIFIC LATE THIS WEEK TO A AMPLIFIED RIDGE OVER THE
EASTERN GULF AND PANHANDLE BY MID NEXT WEEK. OVERALL THIS MEANS A
TRANSITION FROM WEAK SYSTEMS MOVING ACROSS THE GULF TOWARD THE
PANHANDLE FROM THE WEST TO A SLIGHT BLOCKING PATTERN WITH SOME
STORMS HEADING TOWARD SOUTH CENTRAL ALASKA EARLY NEXT WEEK WHILE WE
ARE LEFT TO DRY OUT FOR A FEW DAYS.

CLOSER TO THE SURFACE, FRI INTO SAT WILL FEATURE AT LEAST TWO MORE
WEAK SYSTEMS MOVING THROUGH. THE FIRST IS A WEAK TROUGH LATE THU
NIGHT. THIS TROUGH IS WEAKER AND HAS LESS MOISTURE TO WORK WITH
THEN THE SYSTEM THAT MOVED THROUGH ON CHRISTMAS DAY. THERE WILL
ALSO BE A BIT MORE WARM AIR IN THE INNER CHANNELS SO ANY SNOW WILL
BE CONFINED TO THE HAINES AND SKAGWAY AREAS WITH MAYBE A MIX
A LITTLE FARTHER SOUTH. ACCUMULATIONS SHOULD BE IN THE 1 TO 2
INCH RANGE. FOLLOWING THAT IS A WEAK LOW THAT WILL BE SKIRTING
ACROSS THE SOUTHERN GULF ON FRI NIGHT. MODELS HAVE BEEN HAVING
SOME DIFFICULTY WITH THIS FEATURE. THOUGH THE GENERAL TREND OVER
THE LAST 24 HOURS HAS BEEN TO WEAKEN THE FEATURE AND PUSH THE
TRACK FURTHER SOUTH. CURRENT FORECAST (USING A GFS/12Z ECMWF/GEM
BLEND) HAS IT AS A 1018 MB LOW THAT WEAKENS NEARLY TO NOTHING BY
THE TIME IT GETS TO DIXON ENTRANCE. THE PRECIP WITH THAT SYSTEM
WILL MAINLY BE FOR THE SOUTHERN PANHANDLE AND TEMPS SHOULD BE WARM
ENOUGH FOR IT TO BE ALL RAIN FRI NIGHT.

THINGS ABRUPTLY CHANGE FOR SAT INTO EARLY NEXT WEEK AS THE UPPER
RIDGE BUILDS JUST TO OUR WEST. A 1040 MB HIGH WILL BE BUILDING
INTO THE SOUTHERN YUKON BRINGING SOME NORTHERLY OUTFLOW AND SOME
COOLER TEMPS FOR THE AREA SAT NIGHT INTO MON. OUTFLOW WILL NOT BE
THAT STRONG HOWEVER AS THE OVERALL ATMOSPHERIC PRESSURE IS RATHER HIGH
EVEN OVER THE GULF. HIGHEST WINDS EXPECTED WILL BE IN LYNN CANAL
WITH 25 KT. SKIES WILL BE CLEARING OUT AND AS A RESULT OVERNIGHT
LOWS ON SAT NIGHT AND SUN NIGHT WILL BE A BIT COOLER THEN WHAT WE
HAVE SEEN RECENTLY. EXPECTING THE COLDEST LOWS ON SUN NIGHT SO
HAVE DROPPED LOWS THERE A FEW DEGREES. INTO MID NEXT WEEK, THINGS
GET A BIT INTERESTING AS THE UPPER RIDGE SHIFT SLIGHTLY EAST
BRINGING SOUTHERLY FLOW INTO THE GULF. AT THIS POINT WARM AIR
ADVECTION WILL BE BRINGING WARMER TEMPERATURES IN ALOFT OVER THE
GULF THAT WILL WRAP EASTWARD INTO THE PANHANDLE AND YUKON NEXT
WEEK. HOWEVER LOW LEVEL COLD AIR MAY STICK AROUND THROUGH MID NEXT
WEEK SO TEMPERATURES IN THE INNER CHANNELS MAY NOT GET THAT MUCH
WARMER THAN THE 30S.

NEXT FRONT COMES FOR MID WEEK. TIMING SOMEWHAT OFF BETWEEN MODELS
BUT GENERALLY ALL AGREE ON A FRONT BEING SOMEWHERE IN THE GULF NEXT
WEEK. GENERALLY FAVORED A WPC/ECMWF FOR THE LATE WEEKEND AND
BEYOND.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ041-042-051-052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ043.

&&

$$

JWA/EAL

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