Small Craft Advisory 38, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
351 PM AKST SUN JAN 10 2016

.SHORT TERM...RATHER QUIET WEATHER DAY ACROSS THE PANHANDLE AS THE
GALE FORCE FRONT ACROSS THE GULF REMAINS MOSTLY OFFSHORE. THERE
ARE SOME RAIN SHOWERS ACROSS THE INNER CHANNELS AT THE MOMENT DUE
TO A LINGERING PIECE OF SAT'S FRONT STILL HANGING AROUND THAT
AREA, BUT RAIN HAS BEEN LIGHT. OTHERWISE CLOUDY SKIES WITH SOME
PATCHY LOW CLOUDS ARE THE RULE OF THE DAY. WINDS ARE LESS THEN 15
KT FOR MOST OF THE INNER CHANNELS, HOWEVER THE SOUTHERN PANHANDLE
AND THE OUTER COAST HAVE SEEN SOME GUSTY WINDS UP TO 25 KT TODAY.

MAIN FOCUS FOR THE SHORT RANGE FORECAST REMAINS THE GALE FORCE
FRONT THAT LIES DRAPED OVER THE CENTRAL AND EASTERN GULF TODAY.
THE CENTRAL GULF HAS ALREADY SEEN GALE FORCE WINDS AND THE WINDS
IN THE NORTHERN GULF ARE RISING. THE EASTWARD PROGRESS OF THIS
FRONT IS RATHER SLOW WITH STEERING FLOW MAINLY PARALLEL TO THE
FRONT. HOWEVER SEVERAL SHORT WAVES ARE EVIDENT ALONG THE FRONT ON
SATELLITE IMAGES AND IT WILL BE THESE FEATURES THAT SLOWLY NUDGE
THE FRONT INTO THE PANHANDLE BY MONDAY. FRONTAL PRECIP BANDS WILL
BE STARTING TO AFFECT THE OUTER COAST THIS EVENING AS THE FIRST
SUCH SHORT WAVE PUSHES THE FRONT EAST. PRECIP WILL REACH AS FAR
EAST AS JUNEAU, ANGOON, KAKE, AND PRINCE OF WALES ISLAND BY LATE
TONIGHT. THE FRONT WILL THEN BRIEFLY STALL ITS EASTWARD PROGRESS
BEFORE THE NEXT SHORT WAVE STARTS IT UP AGAIN MON AFTERNOON WITH
THE REST OF THE PANHANDLE GETTING INTO THE RAIN BY THEN.

P-TYPE WILL MAINLY BE TRICKY FOR THE HAINES AND KLONDIKE HIGHWAYS
AND HYDER WITH TEMPERATURES STILL COLD ENOUGH FOR SNOW IN THOSE
AREAS. FOR THE HIGHWAYS, HIGHEST PRECIP RATES WILL BE EARLY MON
INTO MON AFTERNOON, BUT SNOW AMOUNTS MAY BE LIMITED BY HOW MUCH
MAKES IT OVER THE MOUNTAIN RANGES TO THE SOUTH AND HOW WARM TEMPS
GET. CURRENT THINKING HAS AROUND 2 INCHES FOR TONIGHT AND 2 TO 4
INCHES FOR TOMORROW ALONG THE HIGHWAYS. HYDER WILL LIKELY NOT
RECEIVE MUCH IN THE WAY OF SNOW AS THE PRECIP DOES NOT REACH THAT
AREA UNTIL LATE MON AFTERNOON. FOR THE REST OF THE PANHANDLE RAIN
AT SEA LEVEL WILL BE THE MAIN NEWS WITH TEMPERATURES STAYING ABOVE
FREEZING.

WINDS AND SEAS IN THE GULF WILL GRADUALLY BE DECREASING AS THE
FRONT MOVES INLAND. ONLY A SMALL BAND OF SMALL CRAFT WINDS SHOULD
BE LEFT BY MON AFTERNOON IN THE NORTHERN GULF. FOR THE PANHANDLE,
WINDS WILL BE INCREASING WITH GUSTS TO 40 MPH EXPECTED ALONG THE
SOUTHERN OUTER COAST LATER TONIGHT. WINDS WILL DIMINISH TOMORROW
AFTERNOON AS THE FRONT MOVES FARTHER INLAND AND WEAKENS. WIND
DIRECTION IN THE CENTRAL INNER CHANNELS WAS TRICKY AS I HAD SOME
GUIDANCE SUGGESTING S WIND TOMORROW AS SYNOPTIC FLOW OVERTAKES THE
NORTHERNLY PRESSURE GRADIENT, WHILE OTHERS KEEP A NORTH WIND WITH
THE PRESSURE GRADIENT DOMINATE. DECIDED TO KEEP THE NORTHERLY
WINDS THAT WE HAVE IN THERE AT THE MOMENT AS I THINK THE PRESSURE
GRADIENT SHOULD RETAIN ITS STRENGTH INTO TOMORROW AFTERNOON.

SHORT RANGE MODELS WERE IN DECENT AGREEMENT BUT THE GFS DID NOT
INITIALIZE THE INDIVIDUAL WAVES ALONG THE FRONT VERY WELL. NAM AND
ECMWF HAD A BETTER FIT SO DECIDED TO HEAD IN THAT DIRECTION FOR
ANY UPDATES TODAY. OVERALL NOT MANY CHANGES OVER THE PREVIOUS
FORECAST.

.LONG TERM...MONDAY EVENING THE FRONT DISCUSSED ABOVE WILL STILL
BE OVER THE PANHANDLE CAUSING WIDESPREAD RAIN AND SOME SNOW CLOSER
TO THE CANADIAN BORDERS (1-3 INCHES OVERNIGHT). THE FRONT WILL
WEAKEN THROUGH THE NIGHT WITH PRECIP BECOMING MORE INTERMITTENT
AND TRANSITIONING TO SHOWERS. THIS IS DUE TO A NEW LOW APPROACHING
THE AREA FROM THE SOUTH. THIS WILL CAUSE A PERIOD OF OFFSHORE
WINDS TUESDAY MORNING OVER THE NORTHER/CENTRAL PANHANDLE AND A
SHORT BREAK IN THE RAINFALL. AS THE LOW PROGRESSES NORTHWARD BANDS
OF RAIN SHOWERS WILL MOVE THROUGH THE AREA AND N-NELY WINDS WILL
SHIFT SELY FOR A PERIOD. MODELS HAVE PRETTY BIG DIFFERENCES ON
PLACEMENT OF THIS LOW AS IT MOVES INTO THE NE GULF...SO TIMING OF
THE WIND SHIFT MAY CHANGE.

SHOWERS TAPER OFF THROUGH WEDNESDAY AND THURSDAY AS WE LIE BETWEEN
SYSTEMS WITH AN UPPER LEVEL RIDGE OF HIGH PRESSURE OVER THE
EASTERN GULF. DURING THIS BREAK TEMPERATURES START TO COOL
OFF...ESPECIALLY OVERNIGHT. 850MB TEMPS LOWER TO AROUND -6C OVER
JUNEAU FRIDAY THEN CONTINUE TO FALL GOING INTO THE WEEKEND MEANING
GREATER CHANCES FOR SNOW RATHER THAN RAIN. A WEAK BAND OF PRECIP
MAY CROSS OVER THE AREA ON FRIDAY...BUT MODELS ARE LOOKING DRYER.
PRECIP WITH THE NEXT FRONT MOVES UP FROM THE SOUTH LATE FRIDAY
NIGHT OR SATURDAY BUT WEAKENS AS IT PROGRESSES NORTH DUE TO
ANOTHER LOW FOLLOWING IN ITS PATH. THIS WILL LIMIT SNOWFALL
AMOUNTS.

USED AN ENSEMBLE APPROACH FOR UPDATES TODAY DUE TO MODEL SPREAD
FROM RUN TO RUN. ADJUSTED TEMPERATURES DOWN SLIGHTLY TOWARD NEXT
WEEKEND. FORECAST CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM 9 PM AKST THIS EVENING THROUGH MONDAY MORNING
     FOR AKZ027.
         STRONG WIND FROM LATE TONIGHT THROUGH MONDAY MORNING FOR AKZ023.
MARINE...GALE WARNING FOR PKZ036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ022-033>035-053.

&&

EAL/FERRIN

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