Winter Storm Warning 8, NWS Juneau, AK

357 
WWAK47 PAJK 122057
WSWAJK

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE JUNEAU AK
1157 AM AKST SAT NOV 12 2011

AKZ017-019-122200-
/X.EXP.PAJK.WS.W.0008.000000T0000Z-111112T2100Z/
CAPE FAIRWEATHER TO CAPE SUCKLING COASTAL AREA-
HAINES BOROUGH AND LYNN CANAL-
INCLUDING THE CITIES OF...YAKUTAT...HAINES
1157 AM AKST SAT NOV 12 2011

...WINTER STORM WARNING WILL EXPIRE AT NOON AKST TODAY...

THE WINTER STORM WARNING WILL EXPIRE AT NOON AKST TODAY. 

SNOW HAS TAPERED OFF AND LITTLE ADDITIONAL SNOWFALL IS EXPECTED
TODAY. AROUND 1 FOOT OF SNOW FELL ACROSS THE AREA.

THIS WILL BE THE FINAL STATEMENT ON THIS EVENT.

$$

AKZ018-122200-
/X.EXP.PAJK.WW.Y.0022.000000T0000Z-111112T2100Z/
TAIYA INLET AND KLONDIKE HIGHWAY-
INCLUDING THE CITY OF...SKAGWAY
1157 AM AKST SAT NOV 12 2011

...WINTER WEATHER ADVISORY WILL EXPIRE AT NOON AKST TODAY...

THE WINTER WEATHER ADVISORY WILL EXPIRE AT NOON AKST TODAY. 

SNOW HAS TAPERED OFF AND LITTLE ADDITIONAL SNOWFALL IS EXPECTED
TODAY.

THIS WILL BE THE FINAL STATEMENT ON THIS EVENT.

$$

RWT

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
238 PM AKST FRI NOV 11 2011

.SHORT TERM...SATELLITE IMAGERY THIS AFTERNOON SHOWING CIRRUS
CLOUD SHIELD TRACKING EAST AND MOVING OVER HIGH PRESSURE RIDGE IN
THE EASTERN AK GULF. A 955 MB LOW IN THE BERING SEA WITH FRONTAL
BAND EXTENDING IN TO THE NORTHWESTERN GULF. A STORM FORCE LOW
WILL BEGIN TO DEVELOP ALONG THE TRIPLE POINT DEEPENING RAPIDLY TO
AROUND 965 MB AS IT TRACKS EAST ACROSS THE NORTHERN AK GULF. THE
LOW WILL MOVE TOWARDS YAKUTAT BAY SAT AFTERNOON THEN MOVE OVER
THE NORTHERN PANHANDLE INTO THE YUKON. THE WEATHER FRONT
ASSOCIATED WITH THE LOW WILL REACH THE COASTAL PANHANDLE LATE
THIS EVENING AND PUSH OVER THE ENTIRE REGION THROUGH SAT. WINDS
OVER THE AK GULF WILL REACH OR BE JUST BELOW STORM FORCE LATE FRI
NIGHT WITH THE ADVANCING LOW AND PICK UP TO 20 TO 30 MPH OVER THE
COASTAL PANHANDLE WITH 15 TO 25 MPH WINDS OVER THE INTERIOR
PANHANDLE. MAY SEE SOME HIGH GUSTS WITH THE FRONTAL PASSAGE SAT
MORNING INTO THE AFTERNOON.

 PRECIPITATION WILL BEING ALONG THE COAST MOVING OVER THE ENTIRE
PANHANDLE OVERNIGHT. NOW THE BIG QUESTION: SNOW AND HOW MUCH OF
IT. MODEL SOUNDINGS ARE SHOWING GOOD LEVEL OF MOISTURE IN THE
DENDRITIC GROWTH ZONE WITH HIGHEST OMEGA VALUES JUST BELOW.
SURFACE TEMPS FROM THE SOUNDINGS HAVE BEEN RUNNING ON THE COLD
SIDE COMPARED TO CURRENT OBSERVATIONS BUT STILL STARTING WITH A
GOOD POOL OF COLD AIR ALOFT WITH 850 TEMPS -6 TO -8C. ON THE
OTHER HAND THICKNESS LEVELS ARE A BIT ON THE FENCE WITH
1000-850MB NAM SOWING 1285 WITH GFS AT 1290 TONIGHT THEN 1300 AND
1310 RESPECTIVELY TOMORROW. HAVE A FEELING SNOW TOTALS MAY BE
JUST BELOW ADVY LEVELS FOR SOME AREAS. BUT AS THERE IS A GOOD
FETCH OF MOISTURE WITH THE SYSTEM AND DEFINITE LIFT AND COLD AIR
PRODUCING SOME MODERATE SNOWFALL OVERNIGHT KEEPING EXISTING ADVY
IN PLACE. EITHER WAY THE RIDGE OF WARM AIR BEHIND THE FRONT WILL
TRANSITION SNOW TO A RAIN SNOW MIX OR ALL RAIN THROUGH THE DAY
SAT AS SOUTHERLY WINDS INCREASE.

 MODELS WERE IN GOOD AGREEMENT WITH MORNING. NAM INITIALIZED WELL
COMPARING RH TO WATER VAPOR SATELLITE BUT SEEMED TO TRACK THE LOW
A BIT FURTHER NORTH COMPARED TO OVER MODEL CONSENSUS. LIKED THE
EC STRENGTH AND TRACK BUT DECIDED KEEP WITH MORE OF A BLEND AND
INHERITED GRIDS. ANY CHANGES WERE MINOR, DID NOT DROP SNOW
AMOUNTS MUCH TO KEEP WITH IN ADVY LEVEL CRITERIA, BUT AGAIN MAY
BE JUST SHY WITH THE TRANSITION TO WET SNOW. FORECAST CONFIDENCE
IS ABOUT AVERAGE.

.LONG TERM...LOW AND FRONT WILL BE THRU THE AREA BY SAT EVENING.
COLD ADVECTION WILL INTENSIFY OVERNIGHT SAT INTO SUN ON STG WLY
FLOW. A RESIDUAL LOW PRESSURE AREA WILL HANG AROUND THE FAR NERN
GULF SAT NIGHT INTO SUN THEN ANOTHER LOW WILL FORM FURTHER W AS A
REINFORCING SHOT OF COOLER AIR MOVES INTO THE NW GULF SUN NIGHT.
EVENTUALLY THIS LOW WILL DROP SE AS ARCTIC AIR FILTERS IN FROM THE
N BEGINNING TUE AND CONTINUING TO MOVE SWD INTO LATE WEEK. STRONG
ARCTIC HIGH WILL BUILD OVER NW CANADA FOR MID-LATE WEEK. BASICALLY
LEFT PRESSURE/WIND FIELDS AS IS FOR SAT NIGHT INTO MON...BUT DID
USE HPC FOR PRESSURE AND WINDS MON NIGHT INTO LATE WEEK WITH
MODIFICATIONS AS SPECIFIED BELOW.

TRICKY ASPECT OF FORECAST IS WHEN PRECIP WILL TRANSITION FROM RAIN
TO SNOW SHOWERS. USING 1000-850 MB THICKNESS AROUND 1285M IN A
CONVECTIVE ENVIRONMENT IN COMBINATION WITH 850 MB TEMPS OF -8C OR
COLDER...LOOKS LIKE TRANSITION TO SNOW SHOWERS SHOULD OCCUR DURING
SUN OVER THE NRN HALF OF THE AREA...AND AT LEAST A MIX SHOULD
OCCUR OVER THE SRN AREA BY SUN NIGHT. THERE MAY BE ONE OR MORE
TROFS THAT MOVE ACROSS THE GULF SUN INTO TUE...AND THESE WILL KEEP
SHOWERS GOING ESPECIALLY OVER THE CENTRAL PANHANDLE AND E-CNTRL GULF.

ANOTHER BIG CONCERN IS HOW MUCH OF A SWELL RUN UP ONTO THE CENTRAL
COASTAL AREAS OCCURS ON THE STG WLY WINDS. IT LOOKS LIKE BEST
CHANCE FOR ANY COASTAL FLOODING TO DEVELOP WOULD BE DURING EARLY
AFTERNOON SUN HIGH TIDE AS LARGE WLY SWELLS MOVE IN ON STG WLY
WINDS.DOES NOT LOOK LIKE THE STG WLYS WILL ARRIVE IN TIME FOR
THE MIDDAY SAT HIGH TIDE SO THINK FLOODING POTENTIAL THEN WILL BE
MINIMAL. WILL UPDATE SPS TO EMPHASIZE POTENTIAL FOR SUN...BUT WILL
NOT ISSUE ANY WATCHES.

BY MIDWEEK...AS ARCTIC AIRMASS MOVES IN FLOW WILL TURN STGLY N AND
SHOULD SEE CLEARING ACROSS THE AREA. THE LATE WEEK PERIOD LOOKS
COLD...DRY...AND LOCALLY WINDY. BOOSTED WINDS OVER MUCH OF THE
INNER CHANNEL AREAS WED INTO FRI...WITH STORM FORCE WINDS LIKELY
IN LYNN CANAL AND AT LEAST GALE FORCE WINDS OVER REMAINING AREA EXCEPT
FOR THE FAR SRN AREA.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON FOR
     AKZ027.
         WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON AKST
     SATURDAY FOR AKZ017>021-025.
         STRONG WIND FROM LATE TONIGHT THROUGH LATE SATURDAY NIGHT FOR
     AKZ022-023.
MARINE...STORM WARNING FOR PKZ043.
         GALE WARNING FOR PKZ033-036-041-042-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031-032-034-035.

&&

PRB/RWT