Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
000
FXAK67 PAJK 050008
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
408 PM AKDT FRI SEP 4 2015

.SHORT TERM...IT IS A DRY DAY ACROSS MOST OF THE PANHANDLE TODAY
BUT THAT WILL NOT LAST MUCH LONGER. A RATHER MOIST FRONT IS
WORKING ITS WAY ACROSS THE EASTERN GULF AT THE MOMENT AND IS ALREADY
BRINGING RAIN AND SOME WIND TO YAKUTAT AND MOST OF THE GULF. WINDS
ARE ALREADY STARTING TO INCREASE IN THE NORTHERN INNER CHANNELS
AND SOME LIGHT RAIN HAS BEEN OBSERVED AT HAINES, AND ELFIN COVE
THIS AFTERNOON. THE RAIN AND WIND WILL CONTINUE TO INCREASE
STARTING IN THE NORTHERN PANHANDLE THIS EVENING AND SPREADING TO
THE SOUTHERN PANHANDLE BY LATE TONIGHT. THERE IS SOME TROPICAL
MOISTURE ASSOCIATED WITH THE FRONT THAT IT STOLE FROM TYPHOON
KILO A FEW DAYS AGO AND PW DATA BACKS THIS UP MEASURING AROUND 1.1
INCHES IN THE FRONT. AS A RESULT SOME OF THE RAINFALL COULD BE
HEAVY AT TIMES TONIGHT. HOWEVER SINCE THE FRONT WILL BE MOVING
THROUGH THE PANHANDLE RATHER QUICKLY, EXPECTED RAINFALL AMOUNTS
WILL ONLY BE IN THE HALF INCH TO 1.5 INCH RANGE THROUGH SAT
AFTERNOON. AS A RESULT NO HYDRO ISSUES ARE EXPECTED. THE STEADY
FRONTAL RAIN WILL CHANGE OVER TO SHOWERS FOR MOST OF THE PANHANDLE
BY SAT AFTERNOON AS THE MAIN FRONT MOVES INTO CANADA.

AS FOR WIND, MIN GALE FORCE WINDS ARE CURRENTLY BLOWING IN THE
NORTHERN GULF WITH WINDS INCREASING TO SMALL CRAFT OVER THE REST
OF THE GULF. WINDS WILL BE INCREASING ACROSS THE INNER CHANNELS
THIS EVENING AS THE FRONT MOVES IN. HOWEVER WINDS WITH THIS SYSTEM
ARE NOT AS ROBUST AS THE PRECIPITATION. SMALL CRAFT ADVISORIES ARE
THE MAIN WIND HAZARD FROM THIS FRONT AND EVEN THEN IT IS MOSTLY
FOR THE EAST/WEST CHANNELS AND THE SOUTHERN INNER CHANNELS. THE
NORTH/SOUTH CHANNELS ARE FACING A PARALLEL PRESSURE GRADIENT
RELATIVE TO THEIR CHANNEL ORIENTATION SO WINDS WILL BE LIGHTER IN
THOSE AREAS. NO STRONG WIND GUSTS FOR LAND AREAS ARE EXPECTED AS
FORECAST 850 MB WINDS ONLY GET TO 35 KT OVER MOST OF THE
PANHANDLE AS THE FRONT MOVES THROUGH. WINDS DIMINISH TOMORROW
AFTERNOON AS THE FRONT MOVES INTO CANADA.

SHORT RANGE MODELS WERE IN DECENT AGREEMENT THROUGH THE NEXT 24
HOURS. SOME DIFFERENCES WERE NOTED. THE CANADIAN NH MODEL WAS A
LITTLE TOO FAR SOUTH WITH LOW TRACK OVER THE NEXT 24 HOURS, AND
ONE OF THE HI-RES NAM MODELS WERE TOO FAR NORTH. ENDED UP USING
THE GFS AND SOME ECMWF FOR SHORT RANGE GUIDANCE TODAY AS BOTH
SEEMED TO HAVE A DECENT CONSENSUS BETWEEN EACH OTHER AND SOME OF
THE OTHER AVAILABLE MODELS.

.LONG TERM...ACTIVE WEATHER PATTERN THROUGH NEXT WEEK WITH
MULTIPLE LOWS TO AFFECT THE REGION...SOME WITH TROPICAL
CONNECTIONS. THIS IS SOMEWHAT UNUSUAL FOR US SO PATTERN
RECOGNITION/FORECASTING BECOMES MORE UNCERTAIN (FOR BOTH THE
MODELS AND THE FORECASTER).

THE LOW DISCUSSED ABOVE WILL REMAIN IN THE EASTERN GULF THROUGH
SUNDAY THEN GRADUALLY WEAKEN. THIS WILL KEEP SHOWERS IN THE
FORECAST THROUGH SUNDAY...ESPECIALLY OVER THE CENTRAL AND SOUTHERN
ZONES.

THE UPPER LEVEL JET STREAM SHIFTS SOUTH OF OUR AREA ON
SATURDAY AND BECOMES LESS AMPLIFIED. ON MONDAY A JET CORE POINTED
AT HAIDA GWAII WILL HELP TO ENHANCE A LOW CENTER NEAR DIXON
ENTRANCE

A LOW CURRENTLY OVER THE BERING SEA WILL TRACK ACROSS THE GULF OF
AK SUNDAY INTO MONDAY THEN OVER THE SOUTHERN PANHANDLE/DIXON
ENTRANCE MONDAY NIGHT. AT THE SAME TIME THE POST TROPICAL REMNANTS
OF HURRICANE IGNACIO WILL BE APPROACHING FROM THE CENTRAL PACIFIC.
THIS SYSTEM IS CURRENTLY FORECASTED TO PASS SOUTH OF HAIDA GWAII
LATE TUESDAY OR WEDNESDAY AN LARGELY NOT IMPACT OUR WEATHER.
HOWEVER...THE FIRST BERING SEA LOW WILL LIKELY PULL/STEAL SOME
TROPICAL MOISTURE IN FROM IGNACIO. THIS WILL RESULT IN HEAVY RAIN
FOR THE SOUTHERN HALF OF THE PANHANDLE ALL DAY MONDAY. A JET CORE
POINTED AT HAIDA GWAII WILL HELP TO ENHANCE THE LOW AND PRECIP
RATES. THE HEAVIEST RAIN WILL BE MAINLY SOUTH OF SITKA AS THAT
AREA WOULD BE SHADOWED BY THE LOW BEING TO THE SOUTH. THE NORTHERN
HALF OF THE PANHANDLE WOULD BE SHADOWED AS WELL WITH LESS QPF
EXPECTED. THE LOW WILL CONTINUE EAST THROUGH TUESDAY WITH RAIN
DECREASING FROM NORTH TO SOUTH.

AFTER MID WEEK THE UPPER LEVEL JET PATTERN BACKS SWLY AND ONSHORE
OVER THE PANHANDLE. THIS WILL BRING IN MORE CERTAIN WET WEATHER
FOR THE REST OF THE WEEK.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-022-033-035-036-041-042.

&&

$$

EAL/FERRIN

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.