Gale Warning 79, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
247 PM AKST MON JAN 24 2011

.SHORT TERM...THERE WILL BE A SERIES OF WEATHER SYSTEMS THAT
WILL MOVE INTO THE GULF AND AFFECT THE PANHANDLE THROUGH THE NEXT
24 HOURS. THE LATEST SATELLITE IMAGERY SHOWS THE FIRST SYSTEM
ENTERING THE CENTRAL GULF WITH THE ASSOCIATED WEATHER FRONT
MOVING INTO THE EASTERN GULF. THERE IS SOME PERIODS OF RAIN OVER
THE PANHANDLE THIS AFTERNOON BUT AS THE FRONT LIFTS NORTHEASTWARD
THE RAIN WILL BECOME MORE STEADY AND THE WINDS OVER THE COASTAL
AREAS WILL INCREASE TO BE ON THE WINDY SIDE. OVER THE INNER
CHANNELS THE WINDS WILL SLOWLY INCREASE TO BE MIN SMALL CRAFT
OVER MOST AREAS WITH STRONGER WINDS IN E/W CHANNELS. OVER THE
EASTERN GULF SINCE THE TRACK OF THE SURFACE LOW WILL WEST OF
140 THE STRONGEST WINDS WILL BE OVER THE WESTERN AREAS OF OUR
AOR. SOLID GALES WILL SPREAD NORTHWARD THROUGH THE EVENING BUT
BEGIN TO DIMINISH TO RANGE FROM 20 TO 25 KT BY TUE MORNING. SEAS
WILL BUILD TO 20+ FEET OVER THE CENTRAL AND NORTHERN GULF WITH
MID TEENS OVER THE EASTERN GULF.

AS THE UPPER LEVEL LOW ASSOCIATED WITH THE FIRST LOW LIFTS INTO
THE INTERIOR ANOTHER SHORTWAVE TROF WILL LIFT NE AROUND THE PARENT
UPPER LOW OVER THE BERING TO BE OVER THE FAR SOUTH CENTRAL GULF BY
TUE AFTERNOON. THERE WILL BE A BREAK IN THE PRECIP OVER THE
SOUTHERN HALF OF THE PANHANDLE IN THE MORNING BUT THE NORTHERN
AREAS WILL CONTINUE TO SEE PRECIP WITH DEEP ONSHORE FLOW. THE WARM
FRONT ASSOCIATE WITH THE LOW LIFTING INTO THE SOUTHERN GULF WILL
INCREASE PRECIP OVER THE SOUTHERN AREAS THROUGH THE AFTERNOON.
ALONG WITH THE INCREASE PRECIP THE WINDS OVER THE SOUTHERN AREAS
WILL INCREASE TO BE ON THE WINDY SIDE AND CONTINUE TO INCREASE
INTO THE LONG TERM PERIOD. THE WINDS OVER THE NORTHER AREAS WILL
DECREASE THROUGH LATE MORNING INTO THE AFTERNOON AS THE PRESSURE
GRADIENT BECOMES MORE E/W. THE WINDS OVER THE SE GULF WILL
INCREASE TO BE JUST BELOW GALES FROM THE SE WHILE THE WINDS OVER
THE NORTHERN GULF CONTINUE TO DECREASE AS THE FIRST LOW LIFTS
INLAND.

.LONG TERM...LONGWAVE PATTERN REMAINS CONSISTENT FOR THE REST OF THE
WEEK WITH WET AND WINDY CONDITIONS THROUGH THURSDAY THEN A DRYING
TREND TOWARD THE WEEKEND. THE LONGWAVE TROUGH ALONG THE ALEUTIANS
WEAKENS BY WEDNESDAY AND THAT WILL ALLOW A MID LEVEL RIDGE TO
BUILD UP OVER THE PANHANDLE FRIDAY BRINGING AN END TO THE PRECIP
FOR THE WEEKEND. 12Z OPERATIONAL AND ENSEMBLE MODELS DIFFER ON THE
STRENGTH OF THE RIDGE OVER THE PANHANDLE WITH THE 12Z GFS BEING
THE QUICKEST MODEL TO BRING ANOTHER CHANCE OF PRECIP TOWARD THE
PANHANDLE. SINCE THE OPERATIONAL 00Z/12Z ECMWF HAS MUCH BETTER
SUPPORT FROM THE ENSEMBLE SOLUTION PREFERRED TO KEEP INLINE WITH
ECMWF SOLUTION DAY 2 TO 4 BLENDING TOWARD THE HPC SOLUTION INTO
THE WEEKEND WITH THE DRYING CONDITIONS FOR THE PANHANDLE.

A GALE FORCE LOW WILL CONTINUE TO MOVE NORTHWARD TOWARD YAKUTAT
TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING AND ITS ASSOCIATED
FRONTAL BOUNDARY WILL MOVE NORTH ACROSS THE PANHANDLE. THE 850 MB
LLJ WINDS ARE NEAR 55 KNOTS AND SO EXPECT NEAR ADVY LEVEL WIND
GUSTS FOR HYDABURG AND THE SOUTHERN PANHANDLE. LOCALLY WINDY
CONDITIONS WILL ALSO PERSIST IN EAST-WEST ORIENTED CHANNELS AND
ALONG THE REST OF THE OUTER COAST. AS THE SURFACE LOW ADVECTS
INLAND AND REFORMS IN THE YUKON BY WEDNESDAY AFTERNOON WILL SEE A
STRONG SOUTHERLY SURFACE PRESSURE GRADIENT BUILD OVER THE
PANHANDLE AND WILL HAVE AT LEAST SMCR SOUTHERLY WINDS FROM CROSS
SOUND NORTHWARD AND POSSIBLE WIND ADVY GUSTS NEAR SKAGWAY. RAIN
WILL SPREAD NORTHWARD ACROSS THE PANHANDLE TUESDAY EVENING THROUGH
THURSDAY WITH CONTINUED ONSHORE FLOW. THE HEAVIEST RAINFALL WILL
BE TUESDAY NIGHT AS THE UPPER LEVEL JET WILL ENHANCE RAINFALL
RATES. 850 MB TEMPERATURES WILL BE TOO WARM FOR SNOWFALL EXCEPT
ALONG THE NORTHERN ROADWAYS THROUGH THURSDAY BUT WITH THE MAJORITY
OF THE PRECIP FROM JUNEAU SOUTHWARD EXPECT SNOW AMOUNTS LESS THAN
ADVY.

THURSDAY WILL BE THE TRANSITION DAY TO THE DRIER CONDITIONS AS THE
MID LEVEL RIDGE BUILDS OVER THE PANHANDLE ALLOWING THE SHOWER
ACTIVITY TO DIMINISH FROM WEST TO EAST. SURFACE OFFSHORE FLOW
INCREASES THROUGH SATURDAY AND WHILE WILL HAVE PATCHY FOG EACH
MORNING FRIDAY THROUGH SUNDAY...THE OFFSHORE FLOW WILL ALLOW FOR
PARTLY CLOUDY SKIES IN MOST LOCATIONS ACROSS THE PANHANDLE. THE
STRONGEST WINDS OVER THE WEEKEND WILL BE NEAR INTERIOR PASSES AS
THE NORTHEASTERLY SURFACE PRESSURE GRADIENT INCREASES IN STRENGTH
WITH THE BUILDING SURFACE HIGH IN NW CANADA. TEMPERATURES WILL
ALSO RETURN TO NORMAL THROUGH THE WEEKEND AS CAA FROM THE NORTH
INCREASES OVER THE AREA.

THE BIGGEST QUESTION MARK THROUGH THE LONG TERM PERIOD REMAINS HOW
LONG THE DRY WEATHER WILL STICK AROUND AFTER THE WEEKEND. THE 12Z
ENSEMBLE SOLUTIONS BRING BACK A CHANCE OF PRECIP TOWARD MONDAY AS A
FRONTAL BOUNDARY FINALLY HELPS BREAK DOWN THE MID LEVEL RIDGE OVER
THE AREA...BUT ALL MODELS ARE STRUGGLING WITH BREAKING DOWN THE
MID LEVEL RIDGE AND ARE FLIP-FLOPPING ON THE TIMING. WILL NEED TO
WATCH FUTURE MODEL RUNS FOR A BETTER INDICATION ON THE TIMING NEXT
WEEK ON THE RETURN OF PRECIPITATION.

FORECAST CONFIDENCE IS AVERAGE THROUGH THE LONG TERM PERIOD GIVEN
THE 00Z/12Z MODELS ARE NOW COMING INTO AGREEMENT ON THE DRIER
PERIOD OF WEATHER FOR THE PANHANDLE LATE THIS WEEK. EXPECT WET AND
WINDY CONDITIONS WITH ABOVE NORMAL TEMPERATURES THROUGH THURSDAY
THEN A DRYING TREND TOWARD THE WEEKEND WITH TEMPERATURES RETURNING TO
NORMAL.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051-052.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>036-041>043.

&&

ABJ/PSS