Area Forecast Discussion
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FXAK67 PAJK 032352
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
352 PM AKDT SUN MAY 3 2015

.SHORT TERM...MORE SUNSHINE OVER THE NORTHERN PANHANDLE TODAY DUE
TO STRONGER OFFSHORE FLOW AROUND A LOW TO THE DISTANT SOUTH. THE
SOUTHERN PANHANDLE HOWEVER HAS HAD OVERCAST HIGH CLOUDS FROM THIS
LOW ALL DAY. THAT WILL CONTINUE THROUGH MOST OF TOMORROW AS THE
LOW TRACKS EAST TOWARD VANCOUVER ISLAND WITH THE ADDITION OF A
SLIGHT CHANCE OF SHOWERS FOR THE SOUTHERN 3 ZONES. THE GREATEST
CHANCE OF SHOWERS WILL BE COMING FROM THE EAST/BC.

AN INVERTED TROUGH EXTENDING NORTHWARD FROM THE LOW CENTER WILL
INCREASE THE NORTHERLY PRESSURE GRADIENT THROUGH THE INSIDE WATERS
OVERNIGHT AND MONDAY. THIS WILL INCREASE WINDS 15-25KT...STRONGEST
IN NORTHERN LYNN CANAL LATE TONIGHT. SEA BREEZE EFFECTS MONDAY
AFTERNOON WILL HELP TO EASE THE LYNN CANAL WINDS SLIGHTLY IN THE
AFTERNOON...BUT WILL HAVE THE OPPOSITE AFFECT IN PLACES LIKE
CLARENCE STRAIT WHERE NWLY WINDS WILL BE INCREASING TO 20 KT.

SOME AFTERNOON CU HAVE FORMED OVER THE MOUNTAINS TODAY AND EXPECT
THAT TO BE THE CASE AGAIN TOMORROW. AN UPPER LEVEL VORT IS PROGGED
TO MOVE ACROSS THE NORTHERN INNER CHANNELS FROM THE YUKON OVERNIGHT
THEN STRETCH SOUTHWARD OVER THE CENTRAL PANHANDLE THROUGH MONDAY
AFTERNOON. THIS LIKELY WILL ENHANCE THE CLOUDS A BIT SO HAVE GONE
WITH PARTLY CLOUDY SKIES IN THOSE AREAS INSTEAD OF MOSTLY
CLEAR/SUNNY.

MOSTLY CLEAR/PARTLY CLOUDY SKIES OVER THE NORTHERN AND CENTRAL
PANHANDLE WILL ALLOW FOR STRONG RADIATIONAL COOLING AGAIN TONIGHT.
THEREFORE THINK THAT MANY PLACES WILL FALL TO AROUND FREEZING BY
MORNING. THE INCREASING NORTH GRADIENT WILL LIMIT THIS
SLIGHTLY...BUT WIND SHELTERED INNER VALLEYS HAVE A RISK OF FROST.
FOR THIS REASON HAVE ISSUED A FROST ADVISORY TONIGHT FROM KAKE
NORTHWARD (NOT INCLUDING SITKA OR ANGOON ZONES). AS THE FROST
MELTS AFTER SUNRISE...EXPECT PATCHY FOG TO DEVELOP...SIMILAR TO
THIS MORNING IT WILL BE BRIEF. DESPITE THIS MANY LOCATIONS HAVE A
GOOD CHANCE OF HITTING 60F TOMORROW OR SLIGHTLY WARMER THAN TODAY.

MODELS ARE IN GOOD AGREEMENT WITH THE LOW PASSING TO THE SOUTH AND
THE INCREASING NORTH GRADIENT. USED MAINLY THE NAM FOR UPDATES
FOLLOWED BY ADJUSTMENTS FOR LOCAL EFFECTS LIKE SEA BREEZES.

.LONG TERM...PERIOD BEGINS WILL UPPER LOW MOVING INTO BC AND UPPER
RIDGE BUILDING OVER THE GULF OF AK. MODELS IN GOOD AGREEMENT
THROUGH MID WEEK BEFORE RIDGE BEGINS SHIFTING E AND SOLUTIONS BEGIN
DIVERGING. PRECIP CHANCES WILL INCREASE THE SECOND HALF OF THE
WEEK AS S-SWLY UPPER FLOW DEVELOPS IN RESPONSE TO RIDGE SHIFTING
E. THIS WILL ALSO RESULT IN WINDS SHIFTING TO SLY AND INCREASING
OVER THE GULF BY MID WEEK.

LITTLE CHANGE TO INHERITED FORECAST WITH THE NEXT FRONT EXPECTED TO
IMPACT SOUTHEAST ALASKA THU-FRI. MODELS CONTINUE TO SHOW
SIGNIFICANT SPREAD...SO REFRESHED GRIDS WITH WPC GUIDANCE.
GENERALLY A PLEASANT START TO THE WEEK WITH MOSTLY SUNNY SKIES AND
ABOVE NORMAL TEMPS DETERIORATING HEADING INTO NEXT WEEKEND.
FORECAST CONFIDENCE IS ABOVE AVERAGE THROUGH WED THEN FALLS TO
BELOW AVERAGE LATE IN THE WEEK DUE TO MODEL SPREAD.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041.

&&

$$

FERRIN/BC

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