Gale Warning 257, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
551 AM AKDT WED AUG 31 2011

.SHORT TERM...EARLY MORNING SATELLITE IMAGES REVEAL A SURFACE
RIDGE OF HIGH PRESSURE OVER THE EASTERN GULF MOVING SLOWLY
EASTWARD. GENERALLY LIGHT AND VARIABLE WINDS PREVAIL ACROSS THE
FORECAST DOMAIN THIS MORNING. DRY WEATHER CONTINUES ACROSS THE
PANHANDLE UNDER EXTENSIVE MID LEVEL CLOUDS. MODELS ARE IN FAIR
AGREEMENT WITH THE RIDGE OF HIGH PRESSURE CONTINUES TO MOVE
EASTWARD OVER SOUTHEAST ALASKA THIS MORNING THEN MOVE INTO CANADA
LATE THIS AFTERNOON AS A DEVELOPING LOW IN THE NORTHERN GULF
DRIFTS SOUTHEAST INTO THE EASTERN GULF. THE ASSOCIATED OCCLUDED
FRONT WILL ENTER THE EASTERN GULF THIS AFTERNOON AND THEN OVER
ONSHORE THE PANHANDLE TONIGHT. REFRESHED THE INHERITED GRIDS WITH
THE NAM FOR TODAY AND TONIGHT.

AS THE RIDGE TOP MOVES ACROSS THE NORTHERN PANHANDLE THIS
AFTERNOON AND EVENING...SOUTHERLY PRESSURE GRADIENT WILL BE
ENHANCED AND BECOMING STRONG ENOUGH TO GENERATE SMALL CRAFT WINDS
OVER NORTHERN LYNN CANAL WITH BREEZY CONDITIONS FOR SKAGWAY. THE
INCOMING FRONTAL PASSAGE WILL PRODUCE SMALL CRAFT WINDS ACROSS THE
NORTHERN OUTSIDE WATERS THIS AFTERNOON THEN SPREADING THE WINDS
SOUTHEASTWARD THROUGH TONIGHT TO INCLUDE SOUTHERN INNER CHANNELS.
CHANCE POPS ARE EXPECTED TO MOVE INTO THE FORECAST DOMAIN THIS
AFTERNOON AHEAD OF THE INCOMING FRONT. CATEGORICAL POPS WILL BEGIN
OVER YAKUTAT AREA AND ACROSS THE EASTERN GULF EARLY THIS EVENING
THEN QUICKLY MOVE OVER ONSHORE THE PANHANDLE. EXPECT HEAVY RAIN AT
TIMES.

.LONG TERM...THE FRONTAL SYSTEM DISCUSSED IN THE SHORT RANGE
SECTION ABOVE IS THE LAST IN ZONAL FLOW, AND WILL BE FOLLOWED
BY DIMINISH IN PRECIP RATES AND WINDS THU. NOTE HYDROLOGIC
OUTLOOK: THE SPEED OF THIS SYSTEM TRACKING E THROUGH OUR AOR
IS THE REASON THE HEAVY RAINFALL WILL OCCUR IN A RELATIVELY
SHORT TIME.

A SECOND FRONTAL SYSTEM WILL MATTER FOR THIS WEEKEND.  THIS WILL
BE A CYCLOGENETIC SYSTEM ON A LARGER SCALE THAN THE FIRST SYSTEM.
THIS SECOND SYSTEM IS THE BEGINNING OF A FAMILY OF LOWS ASSOCIATED
WITH A LARGE-SCALE TROUGH ALOFT DIGGING S FM OVER PAWD. AT 00Z
SAT A LOW ON THE POLAR FRONT ZONE SHOULD REACH 986 MB ABOUT
100 NM SE OF PAWD AS THE ASSOCD FLOW FM SURFACE TO TROP SPREADS
E OVER OUR ENTIRE AOR.

ANOTHER LARGE-SCALE CYCLOGENETIC SYSTEM WILL OCCUR WITHIN 300 NM
S OF THE AK PEN BUT THE MODELS ARE UNSETTLED ON THE SOLUTION.

MODELS: USED THE GOOD CONSENSUS BETWEEN THE EC AND GFS FOR THE
GULF FOR THAT LOW THAT AT 00Z SAT SHOULD BE ABOUT 986MB AND 100 S
OF PAWD.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR
PKZ011-012-022-033>036-041>043-051-052.

&&

AHN/JBT