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000
FXAK67 PAJK 281323
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
523 AM AKDT MON JUL 28 2014

.SHORT TERM...UPPER LEVEL TROUGH OVER THE AK GULF REMAINS IN
PLACE DUE TO BLOCKING PATTERN WITH HIGH PRESSURE RIDGES EXTENDING
OVER THE ALEUTIANS TO THE WEST AND OVER THE CONUS TO THE EAST. AT
THE SURFACE A COMPLEX AREA OF LOW PRESSURE ROTATING SHORT WAVES
CYCLONICALLY OVER THE PANHANDLE. SATELLITE IMAGERY THIS MORNING
SHOWING A 1014 MB LOW IN THE SOUTHERN AK GULF WITH FIRST FRONTAL
BAND MOVING OVER THE CENTRAL PANHANDLE AND A SECOND EXTENDING
SOUTHWARD INTO THE N PACIFIC. THE FIRST BAND IS MOVING SHOWER
ACTIVITY OVER THE REGION WITH LOW CLOUD COVER AND AREAS OF FOG. A
DEVELOPING WAVE ALONG THE SECOND FRONT WILL DEVELOP INTO A CLOSED
LOW AS IT MOVES TOWARD DIXON ENTRANCE THIS AFTERNOON. MORE RAIN
WILL MOVE OVER THE PANHANDLE THROUGH THE DAY AND INTO TONIGHT.
WITH THE ORIENTATION OF THE FRONT THE TROPICAL MOISTURE FEED WILL
BRING IN 6 HOUR QPF AMOUNTS OVER A QUARTER OF AN INCH, HEAVIEST
AMOUNTS OVER THE SOUTHERN PANHANDLE. NOT EXPECTING THE FOG AND
VERY LOW CLOUD COVER AGAIN TONIGHT WITH THE NEXT FRONTAL BAND.
WINDS WILL INCREASE OVER THE SOUTHERN INNER CHANNELS AND COASTAL
WATERS WITH THE ADVANCING LOW THIS AFTERNOON DUE TO INCREASING
PRESSURE GRADIENT AND 30 TO 35 KT 850 MB LLJ. SMALL CRAFT WINDS
OVER CLARENCE STRAIT WILL CONTINUE THROUGH THE DAY AND AS OF NOW
THINK LOCATIONS SUCH AS SUMNER STRAIT, THE SOUTHERN COASTAL
WATERS AND CROSS SOUND WILL REMAIN JUST BELOW SMALL CRAFT.
DIURNAL TEMPERATURE RANGE WILL AGAIN BE SMALL DUE TO THE PRECIP
AND CLOUD COVER.

MODELS IN GOOD AGREEMENT FOR OVERALL SYNOPTIC PATTERN WITH MORE
SPREAD FOR SURFACE DETAILS. THE ECMWF/NAM INITIALIZED WELL WITH
THE 00Z RUNS BLENDED INTO INHERITED GRIDS. CHANGES WERE MINOR WITH
SLIGHT ADJUSTMENT TO WIND SPEEDS OVER THE CENTRAL INNER CHANNELS.
FORECAST CONFIDENCE IS ABOVE AVERAGE.

.LONG TERM...THE UPPER LEVEL LOW CENTER THAT HAS BEEN CAUSING OUR
WET WEATHER WILL REMAIN IN THE GULF THROUGH THE WEEK BUT OSCILLATE
FROM BEING OVER THE EASTERN GULF ON TUES TO THE SW GULF WED INTO
THE WEEKEND. THIS WILL SHIFT THE FOCUS OF THE STRONGEST ENERGY
AWAY FROM THE PANHANDLE FOR THE LATTER PART OF THE FORECAST AND
ALLOW FOR SOME MORE BREAKS IN THE RAIN.

ON TUESDAY THE LOW DISCUSSED IN THE SHORT TERM SECTION WILL CONTINUE THE
RAIN OVER MUCH OF THE PANHANDLE. THEN AS THE LOW STARTS TO SHIFT TO
THE WEST TUESDAY NIGHT THE RAIN WILL TAPER OFF FROM SE TO NW AND
BECOME MORE SHOWERY THROUGH WEDNESDAY. MODELS ARE IN AGREEMENT WITH
THE DRYING TREND THURS INTO FRIDAY...BUT THE  ECMWF STILL KEEPS SOME
PRECIP AROUND...WHICH IS A BIAS FOR THAT MODEL.

ONLY MADE SMALL ADJUSTMENTS TO THE FORECAST OVERALL. LATEST MODELS
HAD A SLIGHTLY STRONGER LOW IN THE GULF ON TUES AND A STRONGER RIDGE
AS WELL TUE NIGHT OVER THE PANHANDLE SO INCORPORATED THOSE
DIFFERENCES. HOWEVER THE MODELS ALSO HAD LIGHTER WIND SPEEDS OVER
THE GULF. DID NOT WANT TO DECREASE THE SPEEDS THAT MUCH SO LIMITED
CHANGES THERE TO ABOUT 5KTS. OVER THE WEEKEND MODELS HAVE LARGER
DIFFERENCES IN LOW PLACEMENT AND THE NEXT BAND OF RAIN MOVING IN.
HOWEVER BOTH THE ECMWF AND GFS SHOWED RAIN MOVING IN ON SUNDAY...SO
INCREASE POPS TO RAIN LIKELY WHERE BOTH MODELS HAD RAIN. FORECAST
CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036.


$$

PRB/FERRIN






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