FXAK67 PAJK 092136
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
136 PM AKDT SAT MAY 9 2009
.SHORT TERM... MAP ANALYSIS: VERTICALLY STACKED LOW OVER ABOUT
55N/145W SLOWLY MOVING SOUTH SOUTHEAST. A SECOND WEAK LOW OVER
EASTERN PACIFIC IS MOVING NORTHEASTWARD AND WILL REACT WITH THE
VERTICALLY STACKED LOW OVER THE GULF. A WEAK RIDGE OF HIGH
PRESSURE EXTENDS NORTHWARD ALONG THE BRITISH COLUMBIA COAST INTO
THE SOUTHERN PANHANDLE. A MUCH STRONGER HIGH IS IN PLACE OVER THE
BERING SEA WITH A RIDGE EXTENDING INTO THE FAR WESTERN GULF OF
ALASKA AND A RIDGE TO BARROW ON THE ARCTIC SLOPE. 
FORECAST REASONING: RAIN BAND ABOUT THE LOW ESSENTIALLY OVER THE
GULF COAST WATERS AND INTO THE PANHANDLE OVER THE SOUTHERN HALF.
MOST OF THE LOWER LEVEL CLOUDS ARE ROTATING ABOUT THE LOW IN THE
GULF...WHILE SOME OF THE HIGHER CLOUDS ARE STREAMING ONSHORE. AS
THE LOW CONTINUES TO SLOWLY MOVE SOUTHWARD EXPECT TO SEE LOWERING
PROBABILITIES OF RAIN OVER THE NORTHERN PANHANDLE TONIGHT INTO
EARLY SUNDAY. A WEAK TROUGH IN THE UPPER FLOW IS MOVING EAST-
SOUTHEAST IS OVER PRINCE WILLIAM SOUND TO NORTHWAY OR SO. IT WILL
LIKELY TRY AND SKIM THROUGH THE NORTHERN PORTION OF THE PANHANDLE
SUNDAY MORNING.
THE SECOND MOVING NORTHWARD HAS GIVEN AN IMPULSE OF MOISTURE INTO
THE LOW IN THE GULF. THIS MOISTURE WILL LIFT INTO SOUTHEAST GULF
AND START TO CURL INTO THE CENTRAL GULF AND SPREAD INTO THE
SOUTHWEST COASTAL AREAS. EXPECT THIS TO BE MORE STEADY TYPE RAIN
THAN THE ISOLATED TO SCATTERED SHOWERS ONGOING NOW. OVER THEN
NORTHERN PORTION JUST A FEW SPRINKLES OR A VERY LOW CHANCE OF
MEASURABLE ACCUMULATIONS OF RAIN.
WINDS ACROSS THE AREA EXPECTED TO REMAIN FAIRLY LIGHT...GENERALLY
UNDER 20 KT AND SEAS SHOULD ONLY GET TO UP TO 5 OR 6 FT ON THE
OUTSIDE WATERS AND CENTRAL GULF.
MODEL AGREEMENT IN THEN CONTINUING TO BE IN GOOD AGREEMENT WITH
RATHER SOLID RUN TO RUN CONSISTENCY. USED A BLEND OF GFS AND NAM
FOR THE GRID EDITS TODAY.
PERHAPS A LITTLE BIT OF PATCHY FOG OVERNIGHT FOR THE YAKUTAT AREA
OR NORTHERN PANHANDLE BUT NOT ENOUGH FOR SERIOUS TRAVEL PROBLEMS.
EXPECT NO ADVISORIES OR WARNINGS TONIGHT.
.LONG TERM...WEAK AND POORLY ORGANIZED LOWS WILL OCCUR
IN THE GULF OF ALASKA THROUGH DAY 7, AND WILL BE
CHARACTERIZED BY GENERATING CLOUD COVER BUT LITTLE PRECIP. 
THE STRONGEST CYCLONIC FEATURES WILL BE LEESIDE TROUGHS IN 
THE GULF OF ALASKA THAT ARE GENERATED BY NW FLOW OVR THE AK 
RANGE.
PLANETARY SCALE RIDGE ALOFT OVER THE BERING SEA IS DISCUSSED 
BLO DO TO ITS VAST SCALE:  THE ANTICYCLONIC CURVATURE BEGINS
IN THE VICINITY OF THE KAMCHATKA PENINSULA AND REACHES TO 
THE ALASKA RANGE.  THE 500H FLOW FM THE NW CHANGES TO A 
WEAK CYCLONIC CURVATURE OVR THE PNHDL.    
GFS FIVE WAVE 500H DEPICTS A SPLIT FLOW DVLPG ATTM IN A REGION 
ABT 300 NM OF OF THE THE ERN CHAIN.  THE ASSOCD RIDGE WILL 
MATTER FOR OUR FCST DOMAIN, AND WILL GAIN AMPLITUDE WHILE DRFTG
SLOWLY E.  THE GREATEST AMPLITUDE WILL BE REACHED ABT 06Z MON 
WHEN THE RIDGE EXTENDS NNE FM OVR COLD BAY. AT THAT TIME THIS 
RDG ALF WILL BCM QSTNRY.  THRFTR, THIS RIDGE ALOFT WILL SLOWLY
LOSE AMPLITUDE AND ABT 12Z TUE BEGIN TO MOV W. 
GOOD MODEL CONSENSUS THROUGH 00Z THU, AND ONLY MINOR CHANGES HAVE
BEEN MADE.  THE SPREAD AMONG MODEL SOLUTIONS,  AS WELL AS AN
ENSEMBLE SPREAD WITHIN THE NAEFS IS EVIDENT BGNG ABT 12Z THU.
HPC AK GUIDANCE FOR MSL PRES LOADED UP FOR 12Z THU ONWARD,
WITH SFC WINDS CALCULATIONS USING THESE FIELDS.  TEMPERATURES
BYD 00Z THU WERE NUDGED TOWARD HPC AS WELL. 
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
&&
$$
BEZENEK/JBT