Small Craft Advisory 80, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
153 PM AKST FRI JAN 27 2012

.SHORT TERM... SNOW SHOWER REGIME CONTINUES FOR SE ALASKA TODAY
WITH WEST SOUTHWEST FLOW ALOFT...PERSISTENT COLD AIR ALOFT...AND
CELLS ON RADAR & SATELLITE IMAGES. MIDDLETON ISL RADAR SHOWS A
WHIRL OF SHOWERS MOVING DUE E TOWARD THE WATERS OFF YAKUTAT
ASSOCIATED WITH A SFC LOW AROUND 1006 MB 27/18Z. LESS SNOW
AMOUNTS IN TODAYS SHOWERS.

 NEXT SYSTEM REALLY FAR TO SW BUT DEVELOPS RAPIDLY. USED A BLEND
OF MODELS THAT WOULD LOOK LIKE AN ENSEMBLE MEAN OF THE 17/12 GFS
UKMET AND NAM. TRACK IS UP TO 53N WHICH WILL BRING RAIN AND WARM
AIR INTO THE SOUTHERN ZONES AND SOME GALES IN THE OUTER WATERS.
ENOUGH SNOW WILL MOUNT UP IN ZONE 29 TO GET TO A WARNING.
NORTHERLY WINDS AND COLD AIR WILL FILTER INTO THE NORTH ZONES TO
KEEP IT ALL AS SNOW.

.LONG TERM...TRICKY FORECAST FOR MUCH OF THE AREA SAT NIGHT INTO
SUN NIGHT. MAIN ISSUE IS TRACK OF A COMPLEX LOW MOVING NE TOWARD
THE AREA. THE 12Z ECMWF WAS FURTHEST NW NEAR PASI WHILE NAM WAS
FURTHEST SE NEAR DIXON ENTRANCE. GFS/UKMET WERE JUST A BIT TO THE
NW OF THE NAM IDEA...AND THE GEM TOOK A MIDDLE GROUND TRACK. THE
CURRENT FORECAST LINES UP FAIRLY CLOSE TO THE GEM TRACK...AND DUE
TO THE MODEL SPREAD...DECIDED TO KEEP THE LOW TRACK AS IS IN THE
GRIDS. MADE NO CHANGES TO THE FORECAST BEYOND SUN NIGHT.

 HOWEVER DID MAKE SOME TWEAKS TO TEMPS FOR SAT NIGHT INTO
SUN...AS THE N-S TEMP GRADIENT WILL GET RATHER LARGE DUE TO SOME
COLD AIR WORKING SWD INTO THE NRN AREA AND WARMER AIR MOVING NWD
INTO THE SRN AREA. ENDED UP COOLING THE NRN AREA AROUND 5 DEGREES
SAT NIGHT AND SUN. DID NOT CHANGE POPS THOUGH SO WILL HAVE MAINLY
SNOW FOR THE NRN THIRD AND RAIN FOR THE FAR S...WITH TRANSITION
ZONE AROUND THE FREDERICK SOUND AREA. WILL NOT ISSUE ANY
HEADLINES WITH THIS SYSTEM DURING THE LONGER RANGE YET DUE TO LOW
CONFIDENCE IN LOW TRACK AND PRECIP EVOLUTION ESPECIALLY IN THE
COLDER NRN AREAS. WILL EXTEND WSW FOR HYDER AREA TO NOON SUNDAY
HOWEVER. THERE WILL LIKELY BE A FAIRLY SHARP NW EDGE TO THE
PRECIP. DID DECREASE CLOUD COVER 1 CATEGORY TO PARTLY CLOUDY FOR
THE PAYA AREA SAT NIGHT AND SUN.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER STORM WARNING FROM 5 AM SATURDAY TO NOON AKST SUNDAY FOR
     AKZ029.
MARINE...GALE WARNING FOR PKZ041-042.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>036-043-051.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052.

&&

JC/RWT