Gale Warning 374, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
311 PM AKST SUN DEC 14 2014

.SHORT TERM...A FRONTAL BOUNDARY REMAINS STALLED ALONG THE OUTER
COAST. MULTIPLE WAVES ARE RIDING UP THIS BOUNDARY AND HAVE
PRODUCE MODEST INCREASES IN WIND SPEEDS AND GUSTS FROM SOUTH TO
NORTH THROUGH THE DAY. ADDITIONALLY, ONE SUCH WAVE LATE THIS
MORNING WAS RESPONSIBLE FOR AN ABRUPT RISE IN TEMPERATURES. WITH
NOTHING TO DISPLACE THIS WARMER AIR, THE OVERNIGHT LOW TEMPERATURE
FORECAST IS IN JEOPARDY. THIS DOES NOT HAVE TOO MUCH BEARING ON
THE SHORT TERM FORECAST EXCEPT FOR THE HAINES HIGHWAY, WHITE PASS,
AND IN THE MENDENHALL VALLEY NEAR JUNEAU. IF OVERNIGHT LOWS DO PAN
OUT AS FORECAST, IT IS POSSIBLE THAT THE MENDENHALL VALLEY MAY SEE
A LITTLE SNOW LATE TONIGHT. PERSISTENCE WOULD SUPPORT THIS AS
NIGHT TIME LOWS OF LATE HAVE BEEN GETTING DOWN CLOSE TO, OR BELOW
FREEZING. BIGGEST CONCERN IS SNOW ON THE HIGHWAYS. NOT TOO
CONCERNED ABOUT THE KLONDIKE HIGHWAY, SINCE EVEN WITH THE COLDER
OVERNIGHT LOWS, POP AND QPF ARE PRODUCING LESS THAN ADVISORY
AMOUNTS. THE HAINES HIGHWAY WILL BE WHERE THE ACTION WILL BE
TONIGHT. A WEAK SOUTHEAST WIND IN HAINES HAS SET UP AND
TEMPERATURES AS OF EARLY THIS AFTERNOON WERE UP TO 40 DEGREES. NEAR
HAINES CUSTOMS TODAY, LIGHT SNOW THIS MORNING CHANGED OVER TO
LIGHT RAIN WITH TEMPERATURES REMAINING AT OR BELOW FREEZING. SO FAR THE
TEMPERATURE RISE HAS NOT REACHED CUSTOMS AND IF TEMPS REMAIN AS
THEY ARE, MODERATE SNOWFALL AMOUNTS COULD OCCUR LATE TONIGHT
THROUGH THE MORNING TOMORROW OVER THE WESTERN HALF OF THE HAINES
HIGHWAY. THIS MAY BE A BORDERLINE WINTER WEATHER ADVISORY.
TEMPERATURES WILL BE THE DECIDING FACTOR FOR THE PRIMARY
PRECIPITATION TYPE FOR THE EVENT.

USED A BLEND OF NAM AND GFS FOR UPDATES TO PRESSURE AND WIND. POP
AND QPF A BLEND OF ECMWF AND GFS. TEMPS PRIMARILY FROM NAM.
OVERALL FORECAST CONFIDENCE IS AVERAGE.

.LONG TERM...ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THIS
WEEK. A BROAD AREA OF LOW PRESSURE IS FORECASTED TO REMAIN OVER
SOUTHWESTERN ALASKA FOR THE WEEK. A NUMBER OF DISTURBANCES WILL BE
DEVELOPING ON THE EASTERN SIDE OF THIS BROAD LOW. WITH PERSISTENT
SOUTHWEST ONSHORE FLOW, WET AND MILD CONDITIONS WILL BE IN STORE
FOR SOUTHEAST ALASKA FOR MOST OF THE WEEK.

 THE FORECAST CHALLENGE WILL BE WIND. THE START OF THE FORECAST
WILL FEATURE A GALE FORCE LOW TRACKING NORTH TOWARDS NORTHERN GULF
OF ALASKA. THE ASSOCIATED WEATHER FRONT WILL GENERATE GALE FORCE
WINDS ON THE OUTSIDE WATERS. THERE IS A POTENTIAL FOR STRONG WIND
GUSTS OF 35 MPH OR HIGHER ALONG THE OUTER COAST OF PRINCE OF WALES
ISLAND AND BARANOF ISLAND FOR MONDAY NIGHT. THE WINDS ON THE
OUTSIDE WATERS SHOULD SUBSIDE TUESDAY EVENING AS THE FRONT PUSHES
INLAND AND WEAKENS. THERE MAY BE A BRIEF BREAK ON WEDNESDAY BEFORE
THE PATTERN TURNS ACTIVE ONCE AGAIN FOR THE SECOND HALF OF THE
WEEK.

 FOR MOST OF THE PANHANDLE, TEMPERATURES WILL REMAIN ABOVE
FREEZING FOR THE WEEK. PRECIPITATION SHOULD REMAIN AS ALL RAIN.
THE HIGHER ELEVATIONS OF KLONDIKE AND HAINES HIGHWAYS WILL BE
SEEING MEASURABLE SNOWFALL. THE PATTERN OF WARMER THAN NORMAL
CONDITIONS SHOULD PERSIST THROUGH THIS WEEK, AS SOUTHEAST ALASKA
IS STILL INUNDATED WITH MILD MARITIME AIR FROM THE NORTH PACIFIC
OCEAN. THE COLDER AIRMASS IS STILL LOCKED UP IN INTERIOR ALASKA
AND YUKON.

 FORECAST CONFIDENCE IS LOW FOR THE LONG TERM FORECAST PERIOD.
NUMERICAL WEATHER MODELS HAVE POOR RUN-TO-RUN CONSISTENCIES.
BESIDES, THEY ARE DISAGREEING ON THE PLACEMENT OF THE TUESDAY LOW.
BEYOND THAT, MODELS SOLUTIONS DIVERGE FURTHER. USES AN ENSEMBLE OF
GFS/ECMWF/NAM TO REFRESH THE FORECAST PACKAGE THROUGH WEDNESDAY
NIGHT, THEN TRANSITION TO GUIDANCE FROM WPC.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM WARNING FOR PKZ041>043-051-052.
         GALE WARNING FOR PKZ022-033-035-036.
         SMALL CRAFT ADVISORY FOR PKZ021-031-034-053.

&&

FRITSCH/RCL

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