Area Forecast Discussion
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FXAK67 PAJK 281748 CCA
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE JUNEAU AK
946 AM AKDT THU MAY 28 2015

.SHORT TERM...AN UPPER LEVEL LOW THAT BROUGHT RAIN SHOWERS TO THE
PANHANDLE YESTERDAY WAS LOCATED OVER MISTY FJORDS AS OF EARLY THIS
MORNING. WRAP AROUND CLOUD BANDS ARE STILL ROTATING ABOUT THE LOW
AND GENERALLY MOVING NORTHEAST TO SOUTHWEST OVER THE FORECAST
AREA. THE THREAT OF SCATTERED SHOWERS EARLY THIS MORNING EXTENDS
FROM JUNEAU SOUTH TO HYDER, BUT THE MORE NORTHERLY SHOWERS WILL
MOVE OFF TO THE SOUTH WITH THE LOW. BY LATE TONIGHT, ISOLATED
SHOWER ACTIVITY WILL BE PULLING OUT OF THE HYDER AREA. BETWEEN NOW
AND THEN, LOOK FOR ISOLATED THUNDERSTORMS TO FORM OVER EASTERN
PORTIONS OF MISTY FJORDS THIS AFTERNOON AND EARLY EVENING WITH FORECAST
CAPE VALUES BETWEEN 200 AND 300 J/KG AND NEGATIVE LIFTED INDICES.
QPF NOT REALLY ENOUGH TO PUT A DENT IN THE VERY LOW TOTALS SO FAR
THIS MONTH AND MAY 2015 WILL GO DOWN AS ONE OF THE DRIEST MAYS ON
RECORD FOR MANY PANHANDLE LOCATIONS.

TREND ON SKY COVER TODAY WILL BE ONE OF GENERALLY CLEARING FROM
NORTH TO SOUTH, ALTHOUGH FIRST LIGHT IS SHOWING VERY NICE
CONDITIONS ALREADY OVER THE SOUTHERN ZONES AT THE START OF THE
DAY. THERE IS A FAIRLY GOOD CHANCE OF INCREASING CLOUDS OVER THE
SOUTHERN HALF OF THE PANHANDLE FOR PART OF THE DAY TODAY AS WRAP
AROUND MID AND LOW LEVEL CLOUDS CONTINUE TO CIRCULATE AROUND THE
LOW. REGARDLESS, WENT WITH A SOMEWHAT OPTIMISTIC SKY COVER
FORECAST FOR MOST OF THE SHORT TERM FORECAST PERIOD. ONE
PROBLEMATIC AREA WILL BE THE SPEED AND EXTENT OF COVERAGE OF THE
MARINE LAYER WHEN IT RETURNS. HIGH PRESSURE OVER THE GULF AND
NORTHWESTERLY LOW LEVEL WINDS WILL AIDE IN RE-DEVELOPMENT OF THE
MARINE LAYER AND SOME OF THIS CAN BE SEEN ALREADY IN INFRARED
SATELLITE IMAGERY. INITIAL VISUAL SATELLITE IMAGERY THIS MORNING
IS CONFIRMING EXTENSIVE LOW LEVEL STRATIFORM CLOUDS OVER MOST OF
THE EASTERN GULF.

DAYTIME HIGHS WILL REBOUND UNDER MOSTLY SUNNY SKIES TODAY WITH
SOME LOCATIONS REACHING THE MID 70S. OVERNIGHT LOWS EXPECTED DOWN
TO THE MID 40S, BUT TEMPERATURES DOWN TO THE UPPER 30S IN YAKUTAT,
BURWASH, AND HAINES JUNCTION EARLY THIS MORNING WILL NECESSITATE A
CLOSER LOOK AT JUST HOW COLD THINGS WILL GET TONIGHT UNDER MOSTLY
CLEAR SKIES.

NO CHANGES TO PRESSURE. WIND SPEEDS OVER THE GULF DERIVED FROM
GFS. TEMPERATURES ADJUSTED PER BIAS CORRECTED MOS. POP AND QPF
ADJUSTED USING A BLEND OF GEM AND ECMWF. OVERALL FORECAST
CONFIDENCE IS AVERAGE.

.LONG TERM...THERE CONTINUES TO BE GOOD MODELS AGREEMENT IN THE
OVERALL WEATHER PATTERN THROUGH THE WEEKEND WITH DRY, WARM AND
SUNNY CONDITIONS. THERE IS A TREND IN THE MODELS FOR A PATTERN CHANGE
MID NEXT WEEK TO WETTER CONDITIONS WITH INCREASING ONSHORE FLOW
FROM THE WSW. OVERALL THERE WAS NOT MUCH CHANGES DONE IN THE MID
RANGE JUST INCREASED TEMPS ON FRIDAY AND SATURDAY AND THEN
INCREASE CHANCES OF RAIN AND CLOUD COVER ON WEDNESDAY AND THURSDAY.

AT THE START OF THE LONG TERM PERIOD A UPPER HIGH WILL BE OVER THE
GULF WITH A SURFACE HIGH OVER THE GULF OF ALASKA. THIS WILL
PRODUCE SUNNY SKIES WITH VERY WARM CONDITIONS WITH 850MB TEMPS
RANGING FROM +11 TO +14 ON FRIDAY AND SATURDAY. HIGHS WILL BE IN
THE MID TO UPPER 70S WITH SOME INLAND LOCATIONS IN THE LOWER 80S
AND AREAS NEAR THE WATER NEAR 70 WITH SEA BREEZES LIMITING THE
HIGHS. THE HIGH PRESSURE WILL ALSO PRODUCE AN AREA OF SEA STRATUS
OVER THE GULF THAT WILL BE ALONG COASTAL LOCATIONS THAT WILL ALSO
LIMIT HIGH TEMPS TO THE BE IN THE LOWER 60S.

A WEAKENING UPPER LEVEL TROF WILL DROP SOUTH FROM THE YUKON ON
SATURDAY THAT WILL INCREASE THE CHANCES OF SOME SHOWERS NEAR
SKAGWAY IN THE AFTERNOON AND THEN AS IT SLIDES SE NEAR THE JUNEAU
AREA IN THE EVENING. IF THE TEMPS ARE HIGH ENOUGH TO TRIGGERS
SHOWERS THERE MAYBE AN ISOLATED THUNDERSTORM AS IT MOVES OVER THE
MOUNTAINS.

WINDS WILL NOT BE MUCH OF AN ISSUE THROUGH THE WEEKEND WITH NOT
MUCH OF A PRESSURE GRADIENT OVER THE AREA. THERE WILL BE AFTERNOON
SEA BREEZES TO 15 MPH AND MOST MARINE WINDS WILL BE LESS THAN 15
KT. AREAS NEAR CROSS SOUND AND CAPE DECISION THERE MAY BE SOME
ENHANCED WINDS FROM THE THERMAL DIFFERENCE AND PRODUCE NEAR SMALL
CRAFT WINDS FROM THE WNW.

THERE IS SOME DIFFERENCES BETWEEN THE EC AND THE GEM/GFS WITH A
UPPER TROF DROPPING OUT OF THE ARCTIC AND MOVING SOUTH THROUGH THE
YUKON. THE EC IS THE MOST AGGRESSIVE AND STRONGEST WITH THIS
FEATURE AS IT DROPS IT OVER THE NORTHERN PANHANDLE ON MONDAY WHILE
THE GFS/GEM SHEER THE TROF APART OVER THE INTERIOR OF THE STATE.
LATER SHIFTS WILL NEED TO KEEP AN EYE ON THIS AS IT COULD BE A
STRONG UPPER LEVEL FEATURE WITH VERY COLD AIR ALOFT TO INCREASE
THE INSTABILITY.

CLOUDS WILL MOVE BACK INTO THE AREA TUESDAY AS THE UPPER AND MID
LEVEL FLOW BACKS AROUND TO BE ONSHORE WITH THE INCREASED THREAT OF
SIGNIFICANT PRECIP ON WEDNESDAY.

OVERALL THERE IS AVERAGE FORECASTER CONFIDENCE AND USED A BLEND OF
THE NAM/EC FOR FRIDAY WITH SOME GFS ON SATURDAY AND SUNDAY. KEPT
WITH THE WPC FORECAST IN THE EXTENDED PORTION BUT DID INCREASE THE
POPS ABOVE WPC ON DAY 6 AND 7.

&&

.AVIATION...PATCHY FOG AT VARIOUS LOCATIONS ACROSS SOUTHEAST
ALASKA NOT EXPECTED TO CAUSE ANY SIGNIFICANT DELAYS TODAY. FOG WILL
RETURN AGAIN LATE TONIGHT AND MAY HAVE HAVE SOME OPERATION IMPACTS
AT JUNEAU OWING TO LOW TIDE OCCURRING AROUND SUNRISE. LATE
AFTERNOON LOW LEVEL LIGHT CHOP OR TURBULENCE A POSSIBILITY DUE TO
SURFACE HEATING AND LOW LEVEL CONVECTIVE CURRENTS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ022-041.

&&

$$

FRITSCH/ABJ

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