Gale Warning 109, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
555 AM AKST MON FEB 8 2016

.SHORT TERM...A SURFACE LOW WILL BE MOVING NORTH ACROSS THE
EASTERN GULF MONDAY AND INTO THE YUKON TERRITORY LATE MONDAY
NIGHT. THE BAND OF HEAVIER RAINS WILL BE PUSHING NORTHWARD FROM
THE SOUTHERN PANHANDLE THIS MORNING TOWARDS THE NORTHERN
PANHANDLE. MODERATE TO HEAVY RAIN ACROSS THE SOUTHERN PANHANDLE
THIS MORNING. EXPECT THE RAIN THERE TO TAPER OFF TO LIGHT RAIN
INTO THE AFTERNOON. WINDS ARE ALSO RATHER GUSTY ACROSS PRINCE OF
WALES AND SOUTHERN INNER CHANNELS THIS MORNING AS WELL.

A FEW OF THE VERY EARLY MORNING SHOWERS NEAR YAKUTAT HAVE BETTER
ENHANCEMENT AND DEVELOPMENT. THE HEAVIER SHOWERS WERE CREATING
SOME ICE PELLETS AND THAT WILL LIKELY ENDING.

AS THE PRECIP MOVES INTO THE NORTHERN PANHANDLE IT SHOULD START AS
SNOW THERE. FOR HAINES AND HAINES HIGHWAY 2 TO 4 INCHES IS
POSSIBLE...WITH BEST AMOUNTS NEAR THE BORDER. THE KLONDIKE
HIGHWAY WILL SEE THE BEST CHANCE OF ACCUMULATING SNOW. THE SNOW
WILL BE GENERALLY ABOUT 1500 FEET TONIGHT ONWARD AND RISING
OVERNIGHT. AM EXPECTING ABOUT 2 TO 4 INCHES THIS AFTERNOON AND 5
TO 7 INCHES OVERNIGHT. HAVE ISSUED A WINTER WEATHER ADVISORY FOR
SNOW ACCUMULATIONS.

.LONG TERM...TUESDAY INTO THE WEEKEND WILL FEATURE TWO BASIC
PATTERNS. THE FIRST WILL QUICKLY BEGIN SETTING UP ON TUESDAY. THIS
ONE ENTAILS LOW PRESSURE ANCHORED SOUTH OF THE ALEUTIANS OR OVER
THE WESTERN GULF WITH IMPULSES ROUNDING THE FLOW FROM THE SOUTH
AND THEN DETOURING TO THE NORTHWEST JUST AS THEY APPROACH THE
PANHANDLE. THIS FLOW IS CHARACTERIZED BY MILD TO WARM
TEMPERATURES...GENERALLY PERIODS OF LIGHT RAIN AS EACH IMPULSE
PASSES THE PANHANDLE OFFSHORE FOLLOWED BY BRIEF DRY PERIODS
BETWEEN WAVE PASSAGES...AS WELL AS BREEZY CONDITIONS ACROSS BOTH
THE SOUTHERN INNER PASSAGES AND THE COASTAL ZONES. THIS PATTERN
LOOKS TO BEGIN TO DOMINATE OUR WEATHER TUESDAY AFTERNOON AND
PERSIST INTO EARLY FRIDAY.

BY LATE FRIDAY ANOTHER PATTERN LOOKS TO EMERGE...ONE POTENTIALLY
MUCH WETTER FOR SOUTHEAST ALASKA, AND ALSO MILD. THIS ONE
FEATURES SOUTHWESTERLY FLOW FROM AN EXTENDED FETCH ACROSS THE
NORTH PACIFIC WITH EMBEDDED WAVES ENHANCING RAINFALL AND WIND.
NEITHER PATTERN IS GOOD FOR SNOW LOVERS BUT SHOULD SUIT THOSE
PREFER US TO BE SNOW FREE.

TUESDAY AND TUESDAY NIGHT THERE WAS AT LEAST A MODICUM OF
AGREEMENT TO PURSUE CHANGES. AS THE GREAT WEST COAST RIDGE
SUCCUMBS TO THE FIRST SHORT-WAVE ARRIVING FROM THE SOUTH, THE
LAST OF THE SHORT-TERM'S CONVEYOR BELT OF SUBTROPICAL MOISTURE
SHOULD BEGIN TO BREAK DOWN ACROSS THE NORTHERN PANHANDLE. DRYING
CONDITIONS WILL ADVANCE NORTHWARD THROUGH THE DAY FROM THE SOUTH.
HOWEVER, ANY BREAK IS SHORT-LIVED AS THE FIRST WAVE ADVANCES FROM
THE SOUTH TO BRING MORE RAIN FOR THE PANHANDLE AND BREEZY
CONDITIONS FOR MUCH OF THE SOUTHERN AND COASTAL ZONES. A PERIOD OF
A WEAK TAKU WINDS MAY SET UP FOR DOWNTOWN JUNEAU AND DOUGLAS BY
THE AFTERNOON STRETCHING INTO THE EVENING. WITH SUCH A WARM AIR
MASS PRESENT ACROSS SOUTHEAST ALASKA, IT IS DIFFICULT TO BELIEVE
ANY SHORT OUTFLOW SITUATION SHOULD COOL OUR ATMOSPHERE QUICK
ENOUGH TO ALLOW FOR ANY PRECIPITATION TO CHANGE TO SNOW.
THEREFORE, WITH THE EXCEPTION OF WHITE PASS THIS WEEK AND YAKUTAT
TUESDAY MORNING, WE HAVE GONE SNOW-FREE FOR THIS EARLY TO MID
FEBRUARY FORECAST.

FROM WEDNESDAY AND BEYOND WE USED AN ENSEMBLE OF GFS, ECMWF, AND
THE CANADIAN GEM TO PRESENT A ROUGH IDEA OF WHEN GRADIENTS WILL
TIGHTEN, IE, THE MOST LIKELY TIME WHEN SUCCESSIVE WAVES WILL
ARRIVE. POTENTIALLY THE STRONGEST WAVE, THE LAST IN THE SERIES,
INDUCES DRIER RIDGING ACROSS THE PANHANDLE ON THURSDAY
AFTERNOON/EVENING FOR THE BEST CHANCE OF DRY WEATHER, BUT THIS
WILL BE BRIEF AS RAIN MOVES IN TO THE SOUTHERN PANHANDLE BY LATE
THURSDAY NIGHT. FRIDAY WINDS BEGIN TO BACK TO THE SOUTHWEST AS THE
SECOND MORE WET PATTERN EVOLVES.

FORECAST CONFIDENCE FOR TIMING WEATHER/WIND SYSTEMS AVERAGE FOR A
PATTERN WHERE GUIDANCE STRUGGLES. CONFIDENCE MUCH HIGHER FOR WARM
TO MILD TEMPERATURES AND PERIODS OF LIGHT RAIN. USED ECMWF FOR
TUESDAY/TUESDAY NIGHT WITH ECMWF/GEM/GFS FOR WEDNESDAY/WEDNESDAY
NIGHT GOING INTO WPC.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM AKST TUESDAY FOR
     AKZ018.
     STRONG WIND UNTIL 9 AM AKST THIS MORNING FOR AKZ028.
MARINE...SMALL CRAFT ADVISORY FOR PKZ011-022-033>036-041>043-052.
     SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-053.
&&

BEZENEK/JWA

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU