Small Craft Advisory 183, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
359 PM AKST MON MAR 5 2012

.SHORT TERM...A FAIRLY FLAT UPPER LEVEL RIDGE ACROSS THE EASTERN
GULF TODAY WILL MOVE OFF TO THE EAST AND SOUTHEAST THROUGH
TOMORROW AND ALLOW A 150+ KT WSW JET MAX INTO THE NORTHERN
PANHANDLE BY MORNING AND SINK TO THE SOUTHERN PANHANDLE BY
AFTERNOON. A WARM FRONT WILL MOVE INTO THE EASTERN GULF TONIGHT
AND MOVE ACROSS SOUTHEAST ALASKA ON TUESDAY.

 THE STEADY SNOW IS JUST STARTING ACROSS THE EASTERN GULF COAST
WITH AREAS OF SNOW ASSOCIATED WITH THE WEAK OVERRUNNING OVER THE
RIDGE DEVELOPING ACROSS NORTHERN PANHANDLE. EXPECT STEADIER SNOWS
TO SPREAD E AND SE OVERNIGHT AND REACH SOUTHERN AREAS BY TUESDAY
MORNING. IN GENERAL EXPECT SNOW AMOUNTS RANGING FROM 3 INCHES
COASTAL AND SOUTHERN UP TO 7 INCHES ALONG COAST MTNS.

 DO HAVE A FAIRLY COLD AIR MASS IN LOW LEVEL IN PLACE SO EXPECT
ALL AREAS WILL START AS SNOW. OVERALL PRECIP AMOUNTS ARE NOT HUGE
BUT ENOUGH TO SUPPORT SNOW ADVISORIES. WITH JET DROPPING A BIT TO
THE SE THROUGH THE PERIOD...HIGHEST AMOUNTS WILL BE ALONG THE
COAST MOUNTAINS BETWEEN PAJN AND PAPG EARLY TUESDAY. NORTHERN
AREAS WILL STAY COLDER BUT GET LESS PRECIP. SOUTHERN ZONES WILL
TURN TO RAIN IN SHORTER AMOUNT OF TIME BUT HAVE LOWER ADVISORY
THRESHOLDS. WARM FRONT MOVES ONSHORE AROUND 18Z AND IS NEAR
PAJN-PAKT BY 03Z. WILL SEE PRECIP MIX WITH RAIN JUST IN ADVANCE
OF FRONT AND TURN TO ALL RAIN AND DIMINISH AS FRONT MOVES
THROUGH.

 AS RIDGE BREAKS BY THIS EVENING WILL SEE INCREASING SLY
GRADIENTS. HAVE SMCR IN ALL INNER CHANNELS BY TUESDAY MORNING
WITH A GALE DEVELOPING IN LYNN CANAL TONIGHT AND CONTINUING
THROUGH TUESDAY. A STRONG WIND IS EXPECTED FOR PAGY AND WILL BE
INCORPORATED INTO WSW STATEMENT.

 GOOD MODEL AGREEMENT THROUGH THE SHORT TERM. GFS HAD STRONGEST
SLY GRADIENT AND WAS USED FOR PRES AND WIND.

.LONG TERM...THE MODELS ARE IN A BIT BETTER AGREEMENT WITH THE SYSTEM
THAT WILL MOVE INTO THE GULF THURSDAY NIGHT. THERE IS STILL LOW
CONFIDENCE IN THAT PORTION ALONG WITH THE REST OF THE EXTENDS
THROUGH THE WEEKEND. THE EC CONTINUE HAVE POOR RUN TO RUN
CONSISTENCY BUT THERE WAS GOOD AGREEMENT WITH THE GEM ALONG WITH
GEFS WITH A BIT FASTER TRACK. WHEN THE NEW 12Z EC RUN CAME IN IT
SLOWED THE NORTHWARD MOVING OVER THE LOW ON THURSDAY AND LOOKED
LIKE THE 12Z GFS AND THE NAM. BOTH THE 18Z NAM/GFS RUN BOTH LOOK
GOOD FROM RUN TO RUN. SO WITH THAT SAID...FROM WED NIGHT THROUGH
THURSDAY DID A BLEND OF THE GEM AND SOME 12Z GFS AS IT WAS A GOOD
MIDDLE GROUND. THIS WILL BRING A LOW INTO THE GULF BY LATE THURSDAY
AFTERNOON WITH GALES OVER THE GULF, WARM TEMPS AND RAIN OVER THE
FORECAST AREA. FOR THE REST OF THE EXTENDED PORTIONS REFRESHED THE
FORECAST WITH THE LATEST HPC WITH LOW FORECASTER CONFIDENCE.

IN THE MID RANGE OF THE LONG TERM PERIOD THERE IS ABOUT AVERAGE FORECASTER
CONFIDENCE WITH THE WARMER AND WINDY CONDITIONS OVER THE
PANHANDLE. AS THE UPPER RIDGE OVER THE GULF WILL DEVELOP A DEEP SW
FLOW FROM THE NORTH PACIFIC ALONG WITH A 150KT JET MOVING OVER THE
REGION. THE EC HAS BEEN THE BEST MODEL WITH THIS PATTERN AND
OVERALL NOT MUCH CHANGE FROM TUE NIGHT THROUGH WED AFTERNOON. THE
WEATHER FRONT MOVING OVER THE PANHANDLE IN THE SHORT RANGE WILL
STALL OVER THE AREA THROUGH TUE NIGHT. MOST OF THE PRECIP WILL BE
IN THE LIQUID FORM ACROSS THE AREA WITH SO POSSIBLE MIXED PREICP
NEAR PAHN IN THE LATE AFTERNOON AND SNOW NEAR WHITE PASS. THE WARM
MOIST SW FLOW WILL KEEP THE STEADY RAIN GOING INTO WED. THE GUSTY WINDS
FROM THE SOUTH WILL CONTINUE AS A LEE SIDE LOW DEEPENS IN THE
YUKON AND THE SURFACE RIDGE OVER THE PANHANDLE PERSISTS. THIS WILL
KEEP THE GALES OVER NORTHERN LYNN AND SMALL CRAFT OVER THE REST OF
THE MARINE WATERS. OVERLAND WINDS WILL BE ON THE GUSTY SIDE BUT
THE STRONGEST WINDS WILL BE NEAR PAGY WITH GUSTS TO 40 MPH.

THE UPPER RIDGE WILL REMAIN OVER THE GULF INTO WED SO RAIN WILL BE
CAT TO LIKELY ACROSS THE AREA WITH SW FLOW AT MOST LEVELS. THE
SURFACE RIDGE WILL BEGIN TO WEAKEN SOME THROUGH WED SO THE WINDS
OVER THE INNER CHANNELS WILL BEGIN TO DIMINISH THROUGH THE AFTERNOON.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY FROM 3 AM TO 5 PM AKST TUESDAY FOR
     AKZ026.
         WINTER WEATHER ADVISORY FROM 5 AM TO NOON AKST TUESDAY FOR
     AKZ027-028.
         WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM AKST
     TUESDAY FOR AKZ018-019-021-024.
         WINTER WEATHER ADVISORY UNTIL 5 PM AKST TUESDAY FOR AKZ025.
         WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON AKST
     TUESDAY FOR AKZ020-022.
         WINTER WEATHER ADVISORY UNTIL 9 AM AKST TUESDAY FOR AKZ017.
MARINE...GALE WARNING FOR PKZ012-013.
         SMALL CRAFT ADVISORY FOR PKZ011-021-022-031>036-041>043-051>053.

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