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
000
FXAK67 PAJK 301249
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
448 AM AKDT THU JUL 30 2015

.SHORT/LONG TERM...A BROAD UPPER TROUGH IS POSITIONED OVER THE
WRN/CNTRL GULF EARLY THIS MORNING...WITH AN EMBEDDED SHORTWAVE
IMPULSE ROUNDING ITS BASE SW OF THE ALEUTIANS. THIS IMPULSE IS
FORECASTED TO EJECT NE ACROSS THE SERN GULF BY THIS EVENING...AND
THEN THE PANHANDLE DURING THE NIGHT. THE ASSOCIATED SURFACE LOW WILL
DEEPEN IN RESPONSE...EVENTUALLY MOVING OVER COASTAL PORTIONS OF THE
CNTRL PANHANDLE BY 12Z FRI. AS THE SHORTWAVE IMPULSE APPROACHES THIS
EVENING/TONIGHT PW VALUES FROM 1 TO 1.3 INCHES WILL SPREAD ACROSS
THE SRN HALF OF THE PANHANDLE...AND WHEN COMBINED WITH INCREASING
LARGE-SCALE ASCENT...WILL FAVOR MODERATE TO LOCALLY HEAVY RAINFALL.
MEANWHILE...A RIDGE OF SURFACE HIGH PRESSURE WILL GRADUALLY BE
SHUNTED EWD THROUGH TONIGHT...BUT THE GRADIENT WILL REMAIN TIGHT IN
RESPONSE TO THE APPROACHING SURFACE LOW. AS A RESULT...ENHANCED ZONE
OF SLY WINDS ARE PROBABLE OVER THE SRN INNER CHANNELS.

BEYOND THU NIGHT...PREVIOUSLY MENTIONED LARGE-SCALE TROUGH WILL
GRADUALLY SHIFT ESE THROUGH SAT NIGHT...WHILE SURFACE HIGH PRESSURE
BUILDS OVER THE SRN GULF AND NCNTRL/NERN PAC. RESULTANT ONSHORE FLOW
REGIME WILL PROMOTE CONTINUED RAIN CHANCES OVER THE SRN TWO THIRDS
OF THE PANHANDLE. EVOLUTION OF THE TROUGH THEN BECOMES MORE CERTAIN
SUN INTO MONDAY...WITH THE GFS DEVELOPING A CLOSED LOW CENTERED NEAR
HAIDA GWAII...WHILE THE ECMWF DEPICTS A LOW CENTER FURTHER TO THE W
AND SIGNIFICANTLY MORE INTENSE. GIVEN THIS UNCERTAINTY...FEW IF ANY
CHANGES WERE MADE TO THE PREVIOUS FORECAST BEYOND THE SUN/MON TIME
FRAME...WHILE UPDATES THROUGH DAY 3 WERE MADE USING A NAM/GFS BLEND.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012 PKZ041 PKZ042.

&&

$$

GARNER

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.