Gale Warning 105, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST SAT MAR 1 2008

.SYNOPSIS...
.SHORT RANGE...ONSHORE FLOW CONTINUES THIS MORNING AHEAD OF WEAK
MID LEVEL RIDGING. A LIGHTNING STRIKE OCCURRED WITHIN SOME OF THE
STRONGER MORE WELL DEVELOPED SNOW SHOWERS NEAR BARANOF ISLAND AS
THEY CONTINUE TO MOVE EASTWARD. AS THE RIDGE ADVECTS EASTWARD
THIS AFTERNOON IT WILL TURN THE SHOWERS INTO STRATIFORM PRECIP
AND EFFECTIVELY CAP THE CONVECTION. THE NEXT WEATHER SYSTEM IS
TAKING SHAPE NEAR 52N 152W. A SURFACE LOW WILL DEEPEN SOUTHWEST
OF KODIAK ISLAND AND PUSH NORTHWARD ACROSS THE ALASKAN PENINSULA
THROUGH TONIGHT. ITS ASSOCIATED WEATHER FRONT WILL PUSH TOWARD
THE PANHANDLE TONIGHT INTO EARLY SUNDAY. MODEL INITIALIZATION WAS
BEST IN THE NAM AND GFS SO WENT WITH A 50-50 BLEND. THE NAM
CAPTURED THE WIND FIELD BETTER WITH THE FRONTAL OCCLUSION PASSAGE
ON SUNDAY. WHILE THE GFS HAD A BETTER HANDLE ON THE OVERALL
PRECIPITATION EVENT AND PLACEMENT OF THE ARCTIC BOUNDARY ALONG A
LINE PAEL-PAOH-PAJN. SO NUDGED CURRENT GRIDS TOWARD THESE
SOLUTIONS.

FOR TONIGHT OVERRUNNING SHOULD BEGIN AHEAD OF THE FRONT ACROSS
THE NORTHERN PANHANDLE WITH AREAS OF LIGHT TO MODERATE SNOWFALL.
WILL ADD ZONE 22 TO THE CURRENT SNOW ADVY LIST AS THE OVERRUNNING
SHOULD DEEPEN AND ALLOW THEM TO ALSO RECEIVE ADVY SNOWFALL BEFORE
CHANGING TO RAIN BY EARLY SUNDAY. ARCTIC FRONT SHOULD REMAIN
ALONG THE ICY STRAIT CORRIDOR THROUGH LATE TONIGHT BEFORE MOVING
NORTHWARD INTO SUNDAY. BEST FRONTOGENESIS AND DYNAMICS WILL BE
JUST NORTH OF THIS BOUNDARY WITHIN LYNN CANAL AND NEAR HAINES SO
CONTINUE TO EXPECT THE HEAVIEST SNOWFALL IN ZONE 19. FOR THE
SOUTHERN PANHANDLE TONIGHT CONTINUE TO EXPECT RAIN AND SNOW
SHOWERS WITH LIGHT ACCUMULATIONS BEFORE CHANGING TO ALL RAIN BY
LATE TONIGHT WITH THE ADVANCE/DEVELOPMENT OF THE WARM LOW LEVEL
JET.

BY EARLY SUNDAY THE SOUTHERLY LOW LEVEL JET WILL HAVE PUSHED WARM
AIR NORTHWARD ALL THE WAY NORTH TO JUNEAU. SO EXPECT SNOW TO
CHANGE TO ALL RAIN BY EARLY SUNDAY ACROSS THE MAJORITY OF THE
PANHANDLE SAVE ZONE 18 AND 19 WHERE A MIX WILL STILL OCCUR. THE
WEAK SURFACE DEVELOPMENT ALONG THE TRIPLE POINT WEST OF DIXON
ENTRANCE BY SUNDAY MORNING SHOULD LOCALLY INCREASE THE PRESSURE
GRADIENT ACROSS THE SOUTHERN PANHANDLE. THIS WILL ALLOW FOR WIND
ADVY GUSTS IN ZONE 27 AND 28 AND GALES IN CLARENCE STRAIT THROUGH
SUNDAY AFTERNOON. PSS

.LONG RANGE...SOME MODEL DIFFERENCES THROUGHOUT THE LONG
RANGE...HOWEVER THE OVERALL PATTERN SEEMS CONSISTENT.  MADE SOME
MINOR ADJUSTMENTS FOR TOMORROW NIGHT THROUGH MONDAY
NIGHT...OTHERWISE LEFT PACKAGE AS IS.

UPPER LEVEL RIDGE BUILDS OVER THE EASTERN GULF SUNDAY NIGHT AND
PERSISTS IN VARYING DEGREES THROUGHOUT THE PERIOD. A VERY
PROGRESSIVE PATTERN DOES BREAK DOWN THE RIDGE OR SHIFTS IT
EASTWARD TOWARD BRITISH COLUMBIA AT TIMES...HOWEVER THE RIDGE IS
VERY QUICK TO REESTABLISH ITSELF. THE RESULT WILL BE RELATIVELY
WARMER TEMPERATURES AND A WET PATTERN.

THE MAIN FOCUS WILL BE ON A COMPLEX OF SEVERAL LOWS/SHORT WAVES
FORMING IN THE WESTERN GULF/BERING BEGINNING ON MONDAY.  THIS
COMPLEX WILL SHOOT SEVERAL OF THESE SYSTEMS INTO THE GULF
BEGINNING MONDAY NIGHT.  PINPOINTING THE TIMING...STRENGTH AND
LOCATION OF THESE SYSTEM IS DIFFICULT AS MODELS TRADITIONALLY
HAVE DIFFICULTY HANDLING THESE FEATURES.  CONSISTENT
SOUTHWESTERLY FLOW WILL LIKELY KEEP COLD AIR OUTBREAKS AT BAY AND
THEREFORE EXPECT MOST LOCATIONS TO REMAIN RAIN...ESPECIALLY MID
TO LATE WEEK WHEN THE BEST SOUTH-SOUTHWEST PUSH IS EXPECTED.
HANKO

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC... HEAVY SNOW WARNING AKZ019
      ... SNOW ADVY AKZ017-020-021-025

MARINE... GALE PKZ041-042-043-051-052-310
      ... SMCR PKZ011>013-021-022-033>036