000 FXAK67 PAJK 081406 AFDAJK SOUTHEAST ALASKA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JUNEAU AK 506 AM AKST SUN FEB 8 2009 .SHORT TERM...SATELLITE THIS MORNING REVEALS A WELL DEFINED MID LEVEL LOW ADVECTING SOUTHEASTWARD FROM THE WESTERN GULF INTO THE NORTHERN PACIFIC. HOWEVER, A DEFORMATION BAND STRETCHING INTO THE EASTERN GULF IS STRENGTHENING THIS MORNING AND THIS MID LEVEL DEFORMATION BAND ALONG WITH MODERATE MID LEVEL PVA WILL ACT TO ENHANCE THE SNOW SHOWER ACTIVITY THROUGH THE DAY ACROSS THE CENTRAL AND SOUTHERN PANHANDLE. WITH CAA CONTINUING FROM 500 MB DOWN THE SURFACE EXPECT THE MAJORITY OF THE SHOWER ACTIVITY TO BE SNOW ACROSS THE PANHANDLE. SOUNDINGS THIS MORNING ALSO SHOW A SHARP COLD POOL AT 500 MB THAT WILL ADVECT EASTWARD ACROSS THE PANHANDLE THROUGH THE DAY...SO WILL SEE ISOLATED THUNDERSTORMS NEAR THE OUTER COAST WITH ICE PELLETS IN THE STRONGER SHOWERS INLAND. CHANGED THE INHERITED GRIDS QUITE A BIT THIS MORNING AS BOTH THE 00Z/06Z NAM/GFS INDICATE THAT A STRONG LINE OF SNOW SHOWERS COULD ADVECT AND REMAIN IN JUNEAU AND THE ICY STRAIT CORRIDOR THROUGH THE EVENING. THIS STRONG CONVECTIVE BAND OF SNOW SHOWERS MATCHES QUITE WELL THE PROGRESSION OF THE MID LEVEL DEFORMATION BAND THROUGH THE DAY. THE 06Z NAM WAS USED FOR TODAYS FORECAST AS IT INITIALIZED THE MID LEVEL DEFORMATION BAND THE BEST AND HANDLED THE PROGRESSION OF THE SNOW SHOWERS QUITE WELL INTO TONIGHT. BOTH OF THE EUROPEAN MODELS WERE VERY LARGE OUTLIERS THIS MORNING. FORECAST CONFIDENCE IS BELOW AVERAGE WITH TODAYS SHORT TERM FORECAST AS MODELS ALWAYS HAVE DIFFICULTLY WITH THE PRECIP OUTPUT WITHIN MESOSCALE CONVECTIVE DEFORMATION BANDS. FOR TODAY SNOW SHOWERS WILL CONTINUE TO MOVE ONSHORE ACROSS THE CENTRAL AND SOUTHERN PANHANDLE WITH LOCALLY HEAVIER SNOWFALL ALONG THE ICY STRAIT CORRIDOR AS THE MID LEVEL DEFORMATION BAND STRENGTHENS INTO THE AFTERNOON. ATTM EXPECT SNOW AMOUNTS TO REMAIN BELOW ADVY BUT THIS SITUATION BEARS WATCHING. NEAR YAKUTAT WEAK OFFSHORE FLOW WILL REMAIN THROUGH THE DAY AS THE WEAK RESIDUAL SURFACE LOW IN THE NORTHERN GULF DISSIPATES INTO THE AFTERNOON. THIS OFFSHORE FLOW WILL ALLOW THE SNOW SHOWERS NEAR YAKUTAT TO REMAIN SCATTERED TO ISOLATED INTO THE EARLY EVENING. WINDS ACROSS THE PANHANDLE WILL REMAIN BELOW 20 KNOTS THROUGH THE DAY AS THE SURFACE PRESSURE GRADIENT RELAXES, BUT COULD SEE A FEW HIGHER GUSTS NEAR THE STRONGER SHOWERS. WILL HAVE TO WATCH SHOWERS AS THEY MOVE ONSHORE NEAR THE OUTER COAST AS THE TERRAIN ENHANCED CONVECTIVE FORCING COULD AID IN PRODUCING A FEW THUNDERSTORMS. FOR TONIGHT THE MID LEVEL DEFORMATION BAND PROGGED TO BE NEAR THE ICY STRAIT CORRIDOR SHOULD SHEAR APART BY LATE TONIGHT AS THE MID LEVEL TROUGH AS A WHOLE ADVECTS EASTWARD INTO BRITISH COLUMBIA. COULD SEE 1 TO 3 INCHES OF SNOWFALL THIS EVENING ALONG THE ICY STRAIT CORRIDOR BEFORE THE MID LEVEL DEFORMATION BAND SHEARS APART. SNOW SHOWER ACTIVITY FROM THE CENTRAL PANHANDLE SOUTHWARD WILL DIMINISH BY LATE TONIGHT ALLOWING FOR MOSTLY CLOUDY TO PARTLY CLOUDY SKIES ACROSS THE PANHANDLE AND A FEW AREAS OF PATCHY FOG...ESPECIALLY ACROSS THE SOUTHERN PANHANDLE. A SURFACE HIGH WILL BUILD INTO THE YUKON BY LATE TONIGHT AND THIS WILL INCREASE THE SURFACE PRESSURE GRADIENT ACROSS THE NORTHERN PANHANDLE ALLOWING FOR LOCALLY BREEZY CONDITION IN AND AROUND NORTHERN LYNN CANAL AND TAIYA INLET. WILL ALSO HAVE TO MONITOR THE WIND CHILL VALUES NEAR WHITE PASS, BUT ATTM TEMPS SHOULD STAY ABOVE ADVY CRITERIA. .LONG TERM...RELATIVELY QUIET WEATHER PATTERN IN STORE FOR THE NEXT FEW DAYS. A LONG WAVE TROUGH OVER THE AREA CONTINUES TO PRODUCE LIGHT ONSHORE FLOW THROUGH MIDWEEK. THIS WILL BRING SNOW SHOWERS TO THE NORTHERN AND CENTRAL PANHANDLE AND A MIX OF RAIN AND SNOW SHOWERS FOR THE SOUTHERN PANHANDLE. THE NORTHERN PANHANDLE WILL SEE A BETTER CHANCE OF SNOW SHOWERS TUESDAY AS A WEAK SHORT WAVE TROUGH ROTATES INTO THE PANHANDLE. ANY SNOW ACCUMULATION WILL BE LIGHT AS THERE IS LITTLE MOISTURE WITH THE TROUGH. NEXT SYSTEM COMES THURSDAY AS A WEAKENING FRONT LIFTS OVER THE PANHANDLE FROM THE SOUTHWEST. PRESENTLY THE SYSTEM LOOKS LIKE IT WILL BE RELATIVELY DRY AND WILL FADE OUT OVER THE AREA. THE MODEL SEEM TO INDICATE...THOUGH IT IS FAR OUT THERE AND FORECAST CONFIDENCE IS NOT THAT GOOD...THAT A FEW OTHER FRONTS BEHIND THE FIRST WILL MEET THE SAME FATE AS THEY MOVE TOWARD THE PANHANDLE EARLY NEXT WEEKEND. EACH HAVING A LITTLE MORE SUCCESS THEN THE LAST AT BRINGING MORE MOISTURE TO THE AREA. MODELS WERE IN GOOD AGREEMENT OUT THROUGH WEDNESDAY WHERE THEY START TO DIFFER ON THE APPROACHING SYSTEM ON THURSDAY. ULTIMATELY WENT WITH THE CURRENT GFS FOR THE FIRST HALF OF THE LONG TERM TO GET THE DETAILS OF THE WEAK TROUGH COMING ON TUESDAY. THEN ON THURSDAY SWITCH TO A BLEND OF THE HPC GUIDANCE AND THE EC AS THE SOLUTIONS FOR THE TWO WERE RATHER CLOSE TO EACH OTHER AND FIT NICELY WITH THE INHERITED GRIDS. .AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...NONE. MARINE...SMALL CRAFT ADVISORY FOR PKZ022-041>043-051-052. && $$ PSS/EAL