Small Craft Advisory 22, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
327 PM AKST SUN JAN 5 2014

.SHORT TERM...SATELLITE IMAGERY THIS AFTERNOON SHOWING A WEATHER FRONT
OVER THE FAR EASTERN GULF MOVING OVER THE PANHANDLE THEN STALLING
OVER THE PANHANDLE ON MONDAY. A WEAK LOW DEVELOPING ALONG THE
FRONT WILL TRACK NORTHWARD TONIGHT THEN FILL THROUGH MONDAY. THE
FRONT PRODUCED A MIXED OF PRECIPITATION FOR THE NORTHERN AND
CENTRAL PANHANDLE OVERNIGHT AND THROUGH THE DAY SUNDAY. HEAVY SNOW
DEVELOPED OVER THE YAKUTAT REGION AS WINDS SHIFTED TO THE
NORTHEAST THEN TRANSITIONED TO HEAVY RAIN AS WINDS SHIFTED TOT HE
SOUTHEAST. FOR THE CENTRAL PANHANDLE PRECIP WAS MOSTLY RAIN WITH A
MIX OF SNOW. HAINES AND SKAGWAY RECEIVED SNOW ACCUMULATIONS IN THE
2 TO 4 INCH RANGE WITH HIGHEST AMOUNTS AT HIGHER ELEVATIONS.
ELSEWHERE OVER THE PANHANDLE THE EASTERLY FLOW KEPT THE MIX OF
RAIN AND SNOW WILL LITTLE ACCUMULATION. AS THE FRONT PROGRESSES
SOUTHWARD PRECIP OVER THE NORTHERN REGIONS WILL DIMINISH WHILE
RAIN DEVELOPS OVER THE SOUTHERN PANHANDLE. NOT EXPECTING MUCH IN
THE WAY OF DIURNAL TEMPERATURE RANGE AGAIN TONIGHT AND INTO MONDAY
SO SHOULD STILL SEE MOSTLY RAIN OVER NIGHT WITH SOME SNOW FOR THE
NORTHERN AREAS. EXPECT ACCUMULATION FOR THE NORTHERN AREAS TO BE
IN THE 1 TO 2 INCH RANGE TONIGHT WITH LITTLE ACCUMULATION FOR
LOCATIONS WITH MORE OF A RAIN SNOW MIX.

GALE FORCE WINDS OVER THE EASTERN AK GULF DIMINISHED THROUGH THE
DAY AND WILL CONTINUE TO WEAKEN THROUGH MONDAY AS THE FRONT SHEARS
APART. TIGHT PRESSURE GRADIENT OVER THE INNER CHANNELS THIS
AFTERNOON PRODUCED SMALL CRAFT TO GALE FORCE WINDS. AS THE
PRESSURE GRADIENT WEAKENS THIS EVENING SO WILL THE INNER CHANNEL
WINDS. AS THE DEVELOPING GULF LOW MOVES NORTHWARD ALSO EXPECTING
NORTHERN INNER CHANNEL WINDS TO SHIFT FROM THE SOUTH TO NORTH.
ELSEWHERE PARALLEL PRESSURE FIELD NOT SUPPORTING WIND DIRECTION ONE
WAY OR THE OTHER SO KEEPING WITH THE SOUTHERLY SYNOPTIC SCALE
FLOW.

MODELS WERE HAVING ISSUES WITH THE LOW DEVELOPING IN THE GULF. HAD
BEST INITIALIZATION WITH THE 12Z NAM/ECMWF WHICH WERE BIT STRONGER
DEVELOPING THE LOW THAN THE GFS AND WERE USED TO UPDATE INHERITED
GRIDS. MAIN ISSUE TONIGHT IN PRECIP TYPE AND TEMPERATURES. SHOULD
SEE TEMPS LOWER OVER THE NORTHERN AREAS JUST AS PRECIP SUBSIDES,
SO NOT EXPECTING MUCH SNOW ACCUMULATION. HAD A FAIRLY LARGE SPREAD
WITH MOS GUIDANCE TEMPERATURE VALUES WITH POOR CONSISTENCY WITH
RESPECT TO SPATIAL COVERAGE. FORECAST CONFIDENCE IS AVERAGE.

&&

.LONG TERM...FORECAST SOLUTIONS STILL HAVING SOME ISSUES AGREEING
WITH EACH OTHER AND STARTED TO DIVERGE FAIRLY SOON INTO THE
FORECAST PERIOD. ACROSS THE PANHANDLE IT WAS ENOUGH TO WORK WITH
THE DEVELOPING WAVE ON THE FRONTAL BOUNDARY OVER THE EASTERN
PACIFIC AND LIFT IT NORTHWARD TO THE SOUTHERN PANHANDLE BY
TUESDAY MORNING WITH ANOTHER BATCH OF HEAVIER QPF AMOUNTS.

MEANWHILE FURTHER WEST A STRONG LOW MOVING TO THE SOUTHERN BERING
SEA IS SWINGING A LOW AROUND ITS SOUTHERN SIDE AND INTO THE
WESTERN GULF TUESDAY. THIS IS WERE THE MAIN CHOICE CAME FROM ON
THE MODELS. CONFERRING WITH ANCHORAGE WE DECIDED TO STAY WITH THE
ECMWF FORECAST SOLUTION AND THEN TRANSITION INTO THE WPC SOLUTION
WHICH HAS BEEN EC BASED FOR THE LAST FEW DAYS. OVERALL THE
FORECAST TO WEDNESDAY HASN'T CHANGES ALL THAT MUCH.

HOWEVER THE EXTENDED RANGE HAS A SIGNIFICANT CHANGE IN THE
FORECAST. THE ACTIVE WEATHER FOR SOUTHEAST WILL PERSIST INTO NEXT
WEEKEND WITH NOW 2 MORE LOWS MOVING INTO SOUTHEAST ALASKA ONE ON
FRIDAY AND THE SECOND ON SUNDAY. INSTEAD OF A SOFTER BLEND I WOULD
USUALLY TAKE...I PREFERRED TO HIT THE NEWER SOLUTION (BASED ON AND
ECMWF MEAN FORECAST). THIS IS PUTTING A MID 970 MB LOW ACROSS
BARANOF ISLAND LATE THURSDAY. LOCALLY HEAVY RAIN AND STRONG WINDS
ARE QUITE LIKELY WITH THIS EVENT. CONFIDENCE IS AVERAGE OR BETTER
INTO TUESDAY BUT WILL HAVE TO LOW TO MEDIUM FOR THE END OF THE
WEEK. WITH A MORE ZONAL AND THUS ACTIVE FLOW TO IMPACT SOUTHEAST
THE TIMING OF AND STRENGTH OF SYSTEMS IS MUCH MORE DIFFICULT.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 9 PM AKST THIS EVENING FOR AKZ018.
MARINE...GALE WARNING FOR PKZ051.
         SMALL CRAFT ADVISORY FOR PKZ012-021-022-033>036-041>043-052.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ053.

&&

PRB/BEZENEK