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000
FXAK67 PAJK 192352
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
352 PM AKDT SUN MAY 19 2013

.SHORT TERM.../ SUNDAY NIGHT THROUGH MONDAY / A WEAKENING
SURFACE LOW IN THE NORTHERN GULF WILL BE DISSIPATING INTO AN
INVERTED ACROSS THE SOUTHERN HALF OF THE PANHANDLE THROUGH
THROUGH MONDAY. PARTLY TO MOSTLY CLOUDY SKIES. ACROSS THE
SOUTHERN PORTION OF THE GULF A MORE SUBSTANTIAL CLOUD DECK OF
STRATUS/STRATOCUMULUS CLOUDS ARE STREAMING ACROSS THE GULF
TOWARDS THE SOUTHERN PANHANDLE. ACROSS THE LAND AREAS MAINLY
CLOUDY THROUGH THIS EVENING THOUGH THERE ARE SOME BREAKS OVER THE
CHANNELS.

 EXPECT THE SHOWERS WILL BE TAPERING OFF TROUGH THE EVENING WITH
THE SOUTHERN AREAS PROBABLY HANGING ON THE LONGEST. A FEW OF
THESE SHOWERS MAY CONTAIN BRIEF PERIODS OF SLEET. EXPECT SOME
CLEAR OVER THE NORTHERN SECTION TO PERHAPS THE CENTRAL PANHANDLE.
WITH SUFFICIENT HOLES IN THE CLOUDS AND OVERNIGHT LOWS INTO THE
LOWER TO MID 30S. WILL CONTINUE WITH THE PATCHY AREAS OF FROST
AND FROST ADVISORY THAT IS OUT.

 LOCALLY BREEZY IN NORTHERN LYNN CANAL WITH SOUTHERLY SMALL CRAFT
WINDS OR NEARLY SO THROUGH THE EVENING...EXPECT THE GRADIENT TO
SWITCH OVERNIGHT AND THEN BECOME NORTHERLY BY MONDAY INCREASING
BACK TO SMALL CRAFT LEVEL IN THE LATE AFTERNOON.

.LONG TERM...FROSTY START TO TUESDAY MORNING FROM NORTHEAST GULF
INTO NORTH CENTRAL PANHANDLE. OUTFLOW WIND IN DOWNTOWN JUNEAU AND
DOUGLAS AREA FROM MONDAY EVENING INTO TUESDAY NIGHT. SUNNY SKIES
FOR THE WORK WEEK. CLOUDS AND PRECIPITATION ARE LIKELY TO RETURN TO
THE PANHANDLE BY NEXT WEEKEND.

THE BIG NEWS STORY FOR THE LONG RANGE PERIOD IS THE ANTICIPATED DRY
STRETCH THROUGH THE END OF THE WEEK. A STRONG HIGH PRESSURE RIDGE
WILL BUILD FROM NORTH PACIFIC NORTHEASTWARD INTO YUKON AND
NORTHWEST TERRITORIES, WHILE AN INVERTED TROUGH EXTENDS
NORTHWESTWARD FROM PACIFIC NORTHWEST INTO WESTERN BRITISH
COLUMBIA. THE COMBINATION OF THESE WEATHER SYSTEMS WILL ENHANCE
NORTHERLY FLOW THAT WILL USHER IN DRIER CONTINENTAL POLAR AIR FROM
YUKON AND INTERIOR ALASKA INTO THE PANHANDLE.

 WITH CLEAR NIGHTS AND SUNNY DAYS, THE DIURNAL TEMPERATURE RANGE
WILL BE QUITE LARGE (30 DEGREES OR GREATER IN SOME WIND SHELTERED
LOCATIONS). WITH MOSTLY CLEAR SKIES AND NEAR CALM CONDITIONS,
LOCATIONS FROM NORTHEAST GULF INTO NORTH CENTRAL PANHANDLE
(INCLUDING COMMUNITIES OF YAKUTAT, HOONAH, GUSTAVUS, ELFIN COVE,
PELICAN, AND MENDENHALL VALLEY) WILL SEE OVERNIGHT TEMPERATURES
DROP INTO THE LOWER 30S ONCE AGAIN ON MONDAY NIGHT. FROST IS STILL
A POSSIBILITY IN THESE AREAS ON MONDAY NIGHT. FOR TUESDAY, EXPECT
MOSTLY SUNNY SKIES WITH HIGH TEMPERATURES WILL RISING TO THE 60S
ACROSS THE PANHANDLE. THE CONTINENTAL POLAR AIRMASS WILL BE
MODERATING WITH TIME. THUS, THE TEMPERATURES ON TUESDAY NIGHT WILL
BE SLIGHTLY WARMER THAN THAT OF MONDAY NIGHT. THE THREAT OF FROST
WILL BE LIMITED TO THE NORTHEAST GULF. MOSTLY SUNNY SKIES AND
HIGH TEMPERATURES IN THE 60S WILL CONTINUE INTO THE END OF THE
WORK WEEK. WITH HIGH TEMPERATURES IN THE 60S, TEMPERATURES WILL BE
ABOVE NORMAL FOR THIS TIME OF THE YEAR. CLOUDS AND PRECIPITATION
IS LIKELY TO MAKE A RETURN TO THE PANHANDLE BY THE START OF THE
WEEKEND.

 WITH A TIGHT N/S PRESSURE GRADIENT, WINDS WILL BE IN THE 15 TO 25
MPH RANGE FROM MONDAY NIGHT INTO WEDNESDAY. IN THE TRADITIONAL
OUTFLOW AREA, HIGHER WIND GUSTS ARE EXPECTED. THERE IS ALSO A HIGH
LIKELIHOOD OF OUTFLOW WIND HAPPENING IN DOWNTOWN JUNEAU AND
DOUGLAS FROM MONDAY NIGHT INTO WEDNESDAY. SUSTAINED NORTHEAST WIND
UP TO 25 MPH IS EXPECTED. GUSTS CAN BE AS HIGH AS 35 MPH, AS
INDICATED BY NAM. CROSS BARRIER FLOW AND INVERSION ARE FAVORABLE
FOR OUTFLOW WIND TO OCCUR. HOWEVER, THERE IS AN ABSENCE OF
CRITICAL LAYER. WIND GUSTS CAN BE EVEN HIGHER IF CRITICAL LAYER
BECOME FAVORABLE FOR OUTFLOW WIND TO OCCUR.

 THE STRONG OFFSHORE WIND SHOULD KEEP THE MARINE STRATUS OFF THE
PANHANDLE. HOWEVER, IF THESE LOW CLOUDS MAKE IT ONSHORE,
TEMPERATURES MAY NOT BE AS WARM AS ADVERTISED IN THIS FORECAST
PACKAGE AS THE LOW CLOUDS ARE VERY EFFECTIVE IN BLOCKING ALL THE
INCOMING SUNLIGHT.

 FORECAST CONFIDENCE IS ABOVE AVERAGE THROUGH THE WORK WEEK, AND
DECREASES TO AVERAGE FOR THE WEEKEND. MODEL OF CHOICE IS GUIDANCE
FROM ECMWF AND WPC.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...FROST ADVISORY FROM 1 AM TO 7 AM AKDT MONDAY FOR AKZ017-020>022-
     025-026.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-041-042.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ043-051.

&&

$$

BEZENEK/RCL