Small Craft Advisory 203, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
308 PM AKST WED MAR 2 2011

.SHORT TERM...SATELLITE IMAGERY THIS MORNING SHOWS A 968 MB LOW
JUST SOUTH OF THE QUEEN CHARLOTTES TRACKING TOWARD DIXON
ENTRANCE. A SECOND WEAKER VORT LOW TO THE EAST OF THE MAIN LOW IS
TRACKING SOUTH. THE MAIN LOW WILL BEGIN TO WEAKEN AS IT MOVES
NORTH THEN BEGIN TO TRACK NW MOVING OVER THE SE AK GULF. ARCTIC
HIGH OVER THE YUKON REMAINS FIRMLY IN PLACE. THIS PERSISTENT
PATTERN WILL PERSIST. STRONG OUTFLOW WINDS OVER THE PANHANDLE
WILL CONTINUE OVER NIGHT THEN BEGIN TO WEAKEN TOMORROW AFTERNOON
AS THE PRESSURE GRADIENT WEAKENS. UPPER LEVEL TROUGH MOVING OVER
THE PANHANDLE WITH SOUTHERLY WINDS HAD DEVELOPING CRITICAL LEVEL.
ALONG WITH INVERSION ALREADY IN PLACE AND 45 TO 55 KT CROSS
BARRIER FLOW HAVE SEE STRONG TAKU EVENT. THE TAKU EVENT OVER
DOWNTOWN JUNEAU AND SOUTH DOUGLAS WILL CONTINUE TONIGHT WITH
GUSTS OF 70 MPH TO POSSIBLY 90 MPH. SOUTH DOUGLAS ALREADY
REPORTED GUSTS TO 70 MPH TODAY. INSIDE MARINE WINDS HAVE BEEN
SOLID STORM FORCE OVER NORTHERN LYN CANAL WITH UPPER GALE FORCE
TO GALE FORCE WINDS ELSEWHERE WITH HEAVY FREEZING SPRAY OVER THE
NORTHERN REGIONS.

 IN ADDITION TO THE WINDS OVER THE PANHANDLE THE LOW MOVING IN
FROM THE SOUTH WILL BRING PRECIP IN THE FORM OF SNOW TO THE
SOUTHERN PANHANDLE. EXPECTING SNOW TO BE LIMITED TO AREAS SOUTH
OF SUMNER STRAIT. WILL SEE TWO PRECIP BANDS WITH FIRST FRONT
MOVING IN THIS EVENING AND SECONDARY WRAP EARLY THU MORNING. WITH
DRY AIR IN PLACE AND OUTFLOW WINDS EXPECT SNOW AMOUNTS TO BE
LIMITED TO 1 TO 2 INCHES TONIGHT WITH AN ADDITIONAL 1 TO 2 INCHES
TOMORROW. AREAS TO THE SOUTH WILL SEE TEMPS IN THE LOW 30S BUT
STILL EXPECT PRECIP TO REMAIN ALL SNOW AS DEW POINT ARE IN THE
LOW TO MID TEENS.

 MODELS WERE IN GOOD AGREEMENT AGAIN TODAY. EC AND NAM WERE
HANDLING THE SYNOPTIC PATTERN WITH PRESSURE GRADIENT OVER THE
COAST MOUNTAINS WELL WITH THE EC LOOKING THE BEST WRT TO LOW TO
THE SOUTH. UPDATED GRIDS WITH A BLEND OF 12Z NAM AND 00Z EC THEN
USED NAM AND WRF FOR MESO SCALE WIND DETAILS. OVERALL CHANGES
WERE FAIRLY MINOR. FORECAST CONFIDENCE IS ABOUT AVERAGE.

.LONG TERM...THERE WILL BE A LULL IN THE WINDS AT THE START OF THE
LONG TERM PERIOD BUT VERY STRONG WINDS WILL RETURN FRIDAY AND CONTINUE
INTO THE WEEKEND AS ANOTHER LOW MOVES NORTH INTO THE SE GULF BY
SAT. THE MODELS ARE IN GOOD AGREEMENT WITH THE OVERALL WEATHER
PATTERN SO THERE IS HIGH FORECASTER CONFIDENCE. THE BIGGEST CHANGE
TO THE FORECAST WAS TO INCREASE THE NORTHERLY WINDS OVER MARINE
WATERS FOR FRIDAY AND SAT. MAINLY USED THE NAM THROUGH FRIDAY THEN
TRANSITIONED TO A BLEND OF THE PREVIOUS FORECAST WITH THE 12Z EC.

AS THE BEGINNING OF THE LONG TERM PERIOD THE UPPER LOW OVER THE
GULF WILL REMAIN TO SPIN AROUND THE GULF AND SLOWLY SLIDE TO THE
SOUTHERN GULF AS THE HIGH OVER THE BERING LIFTS NORTH INTO THE
ARCTIC THROUGH THE WEEKEND. THE UPPER HIGH WILL DRIFT TO THE ESE
TO BE OVER THE INTERIOR OF THE STATE EARLY NEXT WEEK AND THE LOW
OVER THE SOUTHERN GULF SLIDE SE. THE HIGH WILL REMAIN OVER THE
INTERIOR THROUGH MOST OF NEXT WEEK WITH A MEAN TROF OVER THE NORTH
PACIFIC/SOUTHERN GULF. THIS WILL KEEP THE SE AK ON THE DRY SIDE
FROM SUN THROUGH MID NEXT WEEK WITH TEMPS REMAINING BELOW NORMAL.

AT THE SURFACE THE WEAKENING LOW OVER THE GULF WILL RELAX THE
STRONG NE PRESSURE GRADIENT ON THURSDAY NIGHT SO THE WINDS WILL
DECREASE SOME THROUGH THE NIGHT. THIS WILL NOT LAST LONG AS
ANOTHER SURFACE LOW WILL LIFT NORTH OUT OF THE EASTERN PACIFIC TO
BE NEAR THE QUEEN CHARLOTTES BY FRIDAY AFTERNOON. THIS WILL
TIGHTEN THE NE PRESSURE GRADIENT AND VERY STRONG WINDS WILL RETURN
TO THE NORTHERN HALF OF THE PANHANDLE. THE NORTHERLY WINDS WILL
INCREASE TO STORM FORCE WINDS OVER LYNN CANAL WITH GALES OVER THE
REST OF THE NORTHERN MARINE WATERS ALONG WITH FREEZING TO HEAVY
FREEZING SPRAY. OVER LAND VERY STRONG WINDS FROM THE NORTH WILL
DEVELOP THROUGH FRIDAY AS THE GRADIENT INCREASES. SO WIDESPREAD
WIND ADVY WILL BE IN ORDER ALONG WITH WITH ANOTHER ROUND OF WIND
GUSTS TO 60+MPH NEAR DOWNTOWN JUNEAU. THESE CONDITIONS WILL
CONTINUE INTO SAT BEFORE THE LOW WEAKENS AND DRIFTS OVER THE GULF
AND THE PRESSURE GRADIENT WILL RELAX. OVER THE SOUTHERN AREAS...AS
THE LOW LIFTS NORTH THERE WILL BE WEAK WEATHER FRONT THAT WILL BE
LIKELY POPS WITH POSSIBLE SIGNIFICANT SNOW AMOUNTS FRIDAY NIGHT.
AS THE FRONT LIFTS NORTH THROUGH THE WEEKEND IT LOOKS LIKE IT WILL
FALL APART SO ATTM DO NOT THINK THE NORTHERN HALF WILL GET ANY
PRECIPITATION. THERE WILL BE WEAKER TROF THAT WILL MOVE OVER THE
PANHANDLE LATE SAT INTO SUNDAY THAT WILL INCREASE THE CHANCE OF
PRECIP OF THE NORTH CENTRAL AREAS BUT DO NOT EXPECT IT TO PRODUCE
MUCH QPF.

FOR THE SUNDAY AND THE NEXT WEEK THE CLOUDS WILL DECREASE ALONG
WITH THE THREAT OF PRECIP SO THE PANHANDLE WILL BE MOSTLY CLEAR
WITH DRY CONDITIONS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL NOON AKST THURSDAY FOR AKZ020>022-026-029.
         HIGH WIND WARNING UNTIL NOON AKST THURSDAY FOR AKZ025.
         WIND ADVISORY UNTIL 9 PM AKST THIS EVENING FOR AKZ023.
         WIND ADVISORY UNTIL 5 AM AKST FRIDAY FOR AKZ019.
         WINTER WEATHER ADVISORY UNTIL 5 AM AKST FRIDAY FOR AKZ018.
         HIGH WIND WARNING UNTIL 11 AM AKST THURSDAY FOR AKZ017.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ013-022-031.
         HEAVY FREEZING SPRAY WARNING FOR PKZ011-012.
         HEAVY FREEZING SPRAY WARNING FOR PKZ032-034-035.
         STORM WARNING FOR PKZ012.
         GALE WARNING FOR PKZ011-013-021-022-031>035-042-043-051.
         SMALL CRAFT ADVISORY FOR PKZ036-041-052.

&&

PRB/ABJ