Area Forecast Discussion
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FXAK67 PAJK 222330
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
330 PM AKDT TUE JUL 22 2014

.SHORT TERM...RETURN FLOW AROUND THE LOW PRESSURE SYSTEM OVER
THE NORTHEAST PACIFIC HAS BROUGHT MID AND HIGH CLOUDS FROM JUNEAU
SOUTHWARD TODAY. THIS LOW WILL CONTINUE TO WEAKEN AND DRIFT TO
THE SOUTHEAST OVER THE NEXT 24 HOURS. THE RIDGE OVER THE GULF
WILL SHIFT EAST INTO THE PANHANDLE TONIGHT AND INTO WEDNESDAY AS
A WEAK LOW PRESSURE SYSTEM PUSHES INTO THE CENTRAL AND EASTERN
GULF. THE WEATHER FRONT ASSOCIATED WITH THIS LOW WILL PUSH INTO
OUTER COAST LATER WEDNESDAY MORNING INTO THE AFTERNOON.

ONE OF THE BIGGEST ISSUE FOR THIS FORECAST PACKAGE WAS CLOUD
COVER FOR TONIGHT AND WEDNESDAY. EXPECT THAT CLOUDS ASSOCIATED
WITH LOW TO THE SOUTH WILL BEGIN TO DECREASE THIS EVENING.
HOWEVER, MID AND HIGH CLOUDS WILL BE MOVING IN FROM THE WEST.
THERE WILL BE SOME LINGERING SHOWERS MAINLY ALONG THE COAST
MOUNTAINS AND TO THE EAST. HAVE LEFT A MENTION OF THUNDERSTORMS IN
FOR THE HYDER AREA EARLY THIS EVENING AS THERE STILL REMAINS A
MARGINAL ENVIRONMENT FOR CONVECTIVE DEVELOPMENT IN THAT REGION.
RAIN INCREASES ACROSS THE NORTHERN PANHANDLE LATE WEDNESDAY
MORNING INTO THE AFTERNOON. WHILE MANY AREAS WILL SEE RAIN, EXPECT
AMOUNTS TO BE LIGHT WITH THE HEAVIEST AMOUNTS OVER THE NORTHERN
OUTER COAST. THIS AREA IS EXPECTED TO RECEIVE AROUND A QUARTER
INCH THROUGH LATE WEDNESDAY AFTERNOON.

HAVE INCLUDED A 20 KT BARRIER JET IN MARINE ZONE 52 AFTER
COORDINATION WITH THE ANCHORAGE OFFICE. AM EXPECTING NORTHERN LYNN
CANAL TO REACH SMALL CRAFT ON WEDNESDAY AFTERNOON WITH PRESSURE
GRADIENT BETWEEN JUNEAU AND SKAGWAY TIGHTENING TO AROUND 2 TO 2.5
MILLIBARS. THIS WILL ALSO LEAD TO SOME GUSTY WINDS IN SKAGWAY
DURING THE AFTERNOON AROUND 15 TO 25 MPH. OTHERWISE AM EXPECTING
WINDS TO REMAIN BELOW 20 KTS OVER THE REMAINDER OF THE AREA.

MODELS WERE ALL IN RELATIVELY GOOD AGREEMENT. BLENDED THE 12Z NAM
WITH THE INHERITED GRIDS. CHANGES WERE MAINLY LIMITED TO LOCAL
EFFECT EDITS. FORECASTER CONFIDENCE IS ABOVE AVERAGE.

&&

.LONG TERM...A NARROW RIDGE OF HIGH PRESSURE BUILDS ACROSS THE
EASTERN GULF AND INTO SOUTHEAST ALASKA AHEAD OF FRONTAL BAND
MOVING ACROSS THE GULF AND THEN INTO THE PANHANDLE WED EVENING.
THINK MUCH OF THE SURFACE FEATURE WILL BE WIPED OUT WHILE DOING SO
BUT THE UPPER LEVEL SUPPORT WILL SWEEP RIGHT INTO BRITISH
COLUMBIA. AM EXPECTING A SHORT WAVE OR LOW TO MOVE FROM THE
EASTERN ALEUTIANS TO MOVE INTO THE NORTHERN GULF WEDNESDAY AND
STALL THERE THROUGH THE WEEKEND. MODEL SOLUTIONS ARE SUGGESTING
THAT A SHORT WILL BE DRIVING SOUTHEAST FROM EASTERN RUSSIA OVER
THE BERING INTO THE WESTERN GULF BY THURSDAY.

AN IMPULSE OUT OF THE PACIFIC WILL MOVE ABOUT THE UPPER LEVEL LOW
AND INTO THE PANHANDLE ON FRIDAY AND FRIDAY NIGHT. A FOLLOW UP
WAVE CLOSELY ASSOCIATED TH THE FRIDAY SYSTEM WILL BE SPREADING
INTO THE AREA ON SATURDAY POTENTIALLY WITH SOME HIGHER RAINFALL
TOTALS AS IT PULLS IN SOME MID TROPIC MOISTURE.

LATER TIME FRAMES OF THE FORECAST HAVE A LOWER CONFIDENCE AS THE
RUN TO RUN CONSISTENCY OF THE MODELS TOOK A HIT WHEN NEARLY ALL OF
THEM TOOK A JUMP. FOR THE TIME BEING THE LATER PORTIONS OF THE
FORECAST FOLLOWED THE WPC GUIDANCE WHICH WAS STRONGLY BASED ON AN
ENSEMBLE MEAN FORECAST.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012.


$$

TPS/BEZENEK





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