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FXAK67 PAJK 011424
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
524 AM AKST SUN FEB 1 2015

.SHORT TERM...STRONG OUTFLOW WINDS CONTINUE THIS MORNING AS A
STRONG COLD AREA OF HIGH PRESSURE IN THE SOUTHERN YUKON CONTINUES
TO KEEPS PRESSURE GRADIENTS ALONG THE COAST MOUNTAINS HIGH.
NOTABLE WINDS OVERNIGHT INCLUDE GUSTS TO 45 KT AT SKAGWAY, 74 KT
AT ELDRED ROCK, AND 51 KT AT SOUTH DOUGLAS BOAT HARBOR. PRESSURE
GRADIENTS ACROSS THE COAST MOUNTAINS ARE NOT EXPECTED TO CHANGE
MUCH OVER THE NEXT 24 HOURS SO STRONG WIND GUSTS WILL CONTINUE TO
BE OBSERVED IN THE USUAL OUTFLOW AREAS. STRONG WIND HEADLINES FOR
HAINES, AND GALE AND STORM WARNINGS FOR MANY OF THE NORTHERN INNER
CHANNELS REMAIN UP THROUGH TONIGHT. THE KLONDIKE HIGHWAY CONTINUES
TO HAVE A WINTER WEATHER ADVISORY FOR LOW WIND CHILLS AND BLOWING
SNOW THROUGH TONIGHT AS WELL. PRESSURE GRADIENTS START TO
DIMINISH LATE TONIGHT AS THE CANADIAN HIGH SLOWLY WEAKENS AND
SHIFTS INTO NORTHERN BRITISH COLUMBIA BUT IT WILL NOT BE ENOUGH
YET TO SIGNIFICANTLY REDUCE WINDS TONIGHT.

MEANWHILE THE SOUTHERN HALF OF THE PANHANDLE HAS OVERCAST SKIES
FROM A WEAK FRONT MOVING UP FROM THE SOUTH. THIS FRONT IS NOT
GOING TO MAKE MUCH MORE PROGRESS NORTHWARD AS AN UPPER LEVEL
TROUGH THAT IS DROPPING SOUTHWARD OVER THE NORTHERN PANHANDLE IS
GOING TO KEEP IT MOSTLY WHERE IT IS. THERE IS VERY LITTLE IN THE
WAY OF PRECIP WITH THIS FRONT RIGHT NOW. RADAR SHOWS SOME VIRGA OVER
PRINCE OF WALES ISLAND BUT ONLY A FEW VERY ISOLATED AREAS OF LIGHT
RAIN HAVE BEEN OBSERVED THIS MORNING. THAT SHOULD CHANGE THROUGH
THE DAY AS A NEW TROUGH MOVES UP FROM THE SOUTH REINFORCING THE
FRONTAL TROUGH THAT IS ALREADY ACROSS THE SOUTHERN GULF AND
PANHANDLE. THIS SHOULD BE ENOUGH TO PUSH A BAND OF LIGHT PRECIP
INTO THE SOUTHERN PANHANDLE LATER TODAY INTO TONIGHT. AGAIN
NORTHERLY OUTFLOW AND THE UPPER TROUGH OVER THE NORTHERN PANHANDLE
WILL KEEP THE PRECIP FROM MAKING TOO MUCH PROGRESS NORTHWARD.
FARTHEST NORTH IT MAY GET IS THE SOUTHERN PARTS OF 26 AT MOST.
PRECIP WILL MAINLY BE IN THE FORM OF RAIN FOR 27 AND 28 TODAY BUT
THE ATMOSPHERE SHOULD GET COLD ENOUGH TONIGHT THAT SOME OF THAT
RAIN MAY CHANGE OVER TO SNOW. NOT EXPECTING MUCH ACCUMULATION AS
PRECIP RATES WILL BE RATHER LIGHT AND TEMPS WILL BE NEAR FREEZING.
HYDER THOUGH IS EXPECTED TO BE COLD ENOUGH FOR ALL SNOW WITH UP TO
5 INCHES OF NEW ACCUMULATION EXPECTED BY LATE TONIGHT.

SHORT RANGE MODELS WERE IN GOOD AGREEMENT THROUGH THE NEXT 24
HOURS. MAIN CHANGES TO THE FORECAST WERE MINOR WITH MOSTLY LOCAL
EFFECT CHANGES TO GET MORE DETAILS IN THE FORECAST GRIDS. MAINLY
USED NAM WITH SOME OTHER HI-RES MODELS FOR GUIDANCE WITH THE
OUTFLOW WIND DETAILS.

.LONG TERM...MONDAY MORNING THE STRONG NORTHERLY OUTFLOW WINDS
CONTINUE AND THE WEAKENING TROUGH ALONG THE SOUTHERN PANHANDLE
COAST WILL CONTINUE LIGHT RAIN AND SNOW. THE SNOW IS MOST LIKELY
ALONG THE NORTHERN PERIPHERY OF THE PRECIP AND NEAR INTERIOR
PASSES THAT HAVE COLDER AIR FLOWING OUT OF THEM...IE NEAR KLAWOCK
AND ON THE NORTH SIDE OF KETCHIKAN. SNOWFALL AMOUNTS SHOULD BE
VERY LIGHT AND AROUND 1 INCH NEAR HYDER. OTHERWISE THE PANHANDLE
WILL HAVE A FAIR AMOUNT OF SUNSHINE FOR THE START OF THE WORK
WEEK...ALTHOUGH BRISK.

WIND WILL EASE THROUGH MONDAY NIGHT AS THE YUKON HIGH PRESSURE
SHIFTS TO THE SOUTH INTO B.C. AND WEAKENS SOME. CHANCES OF PRECIP
INCREASE THROUGH MID WEEK AS A WEAK TROUGH SLOWLY DRIFTS NORTHWARD.
THIS FEATURE WILL BE FIGHTING WITH THE COLD/DRY AIRMASS IN PLACE AND
NOT MUCH UPPER LEVEL SUPPORT...SO EXPECT PRECIP TO BE ON THE LIGHT
SIDE.

MODELS DIVERGE WITH PLACEMENT OF A LOW AND ASSOC FRONT THAT MOVES
NORTHWARD OVER THE REGION TOWARD THE END OF THE WEEK. THE GFS NOW
PLACES THE LOW OVER THE NORTHERN GULF WHILE THE ECMWF IS SLOWER DUE
TO A NEW LOW CENTER DEVELOPING OVER THE SE GULF FRIDAY. THESE
DIFFERENCES WILL HAVE A BIG EFFECT ON LOCATION OF PRECIP AND
DURATION OF COLD AIR IN PLACE. FOR THIS REASON HAVE OPTED TO LEAVE THE
CURRENT FORECAST LARGELY IN PLACE WHICH WAS ALREADY BETWEEN THE TWO
SOLUTIONS. DID LOWER POPS AND QPF SOME BECAUSE OF THIS
UNCERTAINTY...HOWEVER IT IS WORTH NOTING THAT BOTH LONG RANGE MODELS
HAVE A SYSTEM MOVING OVER THE AREA THIS WEEKEND WITH COLD/STRONG NORTH
WINDS AGAIN...WHICH COULD RESULT IN AN OVERRUNNING SNOW EVENT FOR AT
LEAST THE NORTHERN PANHANDLE AND POTENTIALLY THE CENTRAL AREAS. THE
FASTER GFS SOLUTION WOULD CAUSE SNOW TO CHANGE OVER TO RAIN IN
JUNEAU FRIDAY NIGHT WHILE THE ECMWF WOULD KEEP IT COLD ENOUGH FOR
SNOW THROUGH SATURDAY. WATCH THIS SPACE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING UNTIL 6 AM AKST MONDAY FOR AKZ025.
         STRONG WIND THROUGH LATE TONIGHT FOR AKZ019.
         WINTER WEATHER ADVISORY UNTIL 6 AM AKST MONDAY FOR AKZ018.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ012.
         STORM WARNING FOR PKZ012.
         GALE WARNING FOR PKZ011-013-021-022-031-032-035-041-043-051.
         SMALL CRAFT ADVISORY FOR PKZ033-034-042-052-053.

&&

$$

EAL/FERRIN

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