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FXAK67 PAJK 302353
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
353 PM AKDT WED JUL 30 2014

.SHORT TERM...UPPER LOW CONTINUES TO RESIDE OVER THE GULF THIS
AFTERNOON...WHILE A SECOND TROUGH IS DROPPING SEWD OVER NWRN
CANADA. THE CANADIAN TROUGH WILL EXIT EWD ACROSS THE NW
TERRITORIES DURING THU...WITH THE ONLY IMPACT TO SE AK BEING A
BRIEF INCREASE IN MIDLEVEL CLOUDINESS OVER NRN PORTIONS OF THE
PANHANDLE. MEANWHILE...THE GULF LOW IS FORECAST TO DRIFT SSWWD
AWAY FROM THE PANHANDLE...LEAVING THE REGION BENEATH A MIDLEVEL
COL WITH HIGH PRESSURE BUILDING AT THE SURFACE. THE AIRMASS WILL
EXPERIENCE SIGNIFICANT DRYING AS THIS TAKES PLACE...WITH ISOLATED
TO SCATTERED SHOWERS ONGOING WED AFTERNOON COMING TO AN END BY THU
MORNING. INCREASING SUBSIDENCE ALOFT/HIGH PRESSURE AT THE
SURFACE...AND THE POTENTIAL FOR ENHANCED RADIATIONAL COOLING IN
RESPONSE TO DECREASING CLOUD COVER WILL FAVOR FOG DEVELOPMENT LATE
TONIGHT. HOWEVER...MODEL GUIDANCE SHOWS THE BOUNDARY LAYER WILL
BEGIN TO DRY OVERNIGHT AS FLOW TAKES ON A WEAK OFFSHORE COMPONENT.
THUS...ONLY EXPECT PATCHY FOG ATTM.

THU IS SHAPING UP TO BE A PRETTY NICE DAY OVER MUCH OF SE AK. MIN
TEMPERATURES WED NIGHT ARE FORECAST TO BOTTOM OUT IN THE MID 40S
TO LOW 50S DUE TO CLEARING SKIES. HOWEVER...HIGHS WILL REBOUND
INTO THE MID 60S TO LOW 70S. PREVIOUS FORECAST HANDLED THIS
DIURNAL TREND WELL...THUS ONLY MINIMAL CHANGES WERE MADE.
PREVIOUS PRESSURE/WIND FORECAST WAS ALSO ON TRACK...WITH A
GEM/ECMWF/NAM BLEND RESULTING IN FEW MODIFICATIONS. DUE TO
EXCELLENT MODEL AGREEMENT...PREDICTABILITY/FORECAST CONFIDENCE IN
THE SHORT TERM APPEARS TO BE HIGH.

.LONG TERM...SUNNY DRY WEATHER IS LOOKING TO STAY AWHILE...AT
LEAST THROUGH THE EARLY WEEKEND. TRUE, WE ARE ALWAYS A LITTLE
RETICENT ABOUT GOING FULL SUN FOR MUCH OF THE COAST WITH ANY KIND
OF RIDGE OVER THE GULF. AT THIS POINT...THERE WILL LIKELY BE SOME
STRATUS DEVELOP OVER THE NORTHERN GULF SOMEWHERE, BUT LET US WAIT
UNTIL IT FORMS TO LOOK WHERE IT SPREADS. WHILE UPPER 60S AND LOWER
70S WILL DOMINATE OVER THE MAINLINE PANHANDLE...YAKUTAT`S
TEMPERATURE HAS BEEN HEDGED TO THE MIDDLE 60S. LOOKING AT
THICKNESSES...HIGHS ON SATURDAY SHOULD BE SIMILAR IF NOT WARMER
THAN FRIDAY. WHILE LOW TEMPERATURES WILL DIP MAINLY INTO THE UPPER
40S FOR THE PANHANDLE...THIS WILL BE MAINLY BECAUSE OF CLEARING
AND LIMITED THE COOLING TO AROUND 45 OR SO. GENERALLY THE AIR MASS
ITSELF IS A WARMER ONE. THE BOUNDARY LAYER SHOULD DRY OUT
SIGNIFICANTLY ON WEDNESDAY TO PREVENT FOG BEING AN ISSUE FOR
EARLY THURSDAY MORNING.

LATE IN THE WEEKEND...THE CUT-OFF UPPER LOW OVER THE SOUTHWEST
GULF WILL GET PULLED NORTHEAST BY A MODERATELY STRONG PUSHING
ACROSS THE BROOKS RANGE AND NORTHERN YUKON. SOME TYPE OF A SHORT-
WAVE WILL REV UP AT ITS BASE AND LIKELY PLACE A SMALL CRAFT LOW IN
THE EASTERN GULF. BOTH ECMWF AND GEM ARE STRUGGLING WITH
THIS: BOTH ON STRENGTH AND TIMING. WHILE THE GFS AGREES WITH THE
UPPER LEVEL LOW PUSHING NORTHEAST, IT SEEMS TO BE DILUTING THE
ENERGY OF THE SHORT-WAVE CIRCULATING ITS BASE WITH SOME SORT OF
PRE-FRONTAL WAVE THAT THE OTHER TWO MODELS HAVE, TOO. HOWEVER IT
FAILS TO PICK UP ON WHAT APPEARS TO BE THE MAIN SURFACE LOW
FOLLOWING THE PRE-FRONTAL WAVE. USED THE POSITIONING OF BOTH THE
GEM AND PREVIOUS RUN OF THE ECMWF WITH THE STRENGTH OF THE CURRENT
ECMWF TO REPRESENT THIS FEATURE. MARINERS WILL NOTE A DECENT
CHANGE FOR THIS WEEKEND WITH SOUTHEAST WINDS INCREASING SUNDAY TO
20 TO 25 KT AND REMAINING SO THROUGH MONDAY. THIS IS OUR BEST
GUESS AT THE MOMENT AND HAS PLENTY OF TIME TO BE STUDIED: A BASE
FROM WHICH A TREND IN STRENGTH CAN BE ESTABLISHED. PREFERRED A
CHANCE OF RAIN BEGINNING SUNDAY ALONG THE COAST...BUT HOLDING OFF
UNTIL SUNDAY NIGHT FOR THE INTERIOR PANHANDLE AS THE PRE-SYSTEM
WAVES BRUSHES PAST AND COATS SKIES WITH CLOUDS PANHANDLE-WIDE. THE
MAIN FEATURE WILL ARRIVE WITH SOME RAIN BECOMING A LITTLE MORE
LIKELY BY LATE MONDAY.

THE NEXT WEEK LOOKS WETTER AND MORE CLIMATOLOGICALLY NORMAL FOR
AUGUST AS THE LOW IN THE GULF BROADENS AND KEEPS CLOUDS AND
ONSHORE FLOW OVER THE PANHANDLE. HIGH TEMPERATURES WILL COOL MAINLY
IN THE LOWER 60S WHILE LOWS WILL WARM BACK NEAR 50.

FORECAST CONFIDENCE GOOD THROUGH SATURDAY WITH CONFIDENCE FALLING
SUNDAY THROUGH TUESDAY WITH THE TIMING AND STRENGTH OF LOW
ENTERING FROM THE SOUTHERN STAGE. CONFIDENCE BUILDS SOMEWHAT AFTER
THE LOW FOR CLOUDIER SKIES AND CHANCES OF RAIN.

&&

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

&&

$$

GARNER/JWA

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