Small Craft Advisory 74, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
227 PM AKDT FRI AUG 12 2011

.DISCUSSION...
ALOFT...UPPER RIDGE OVER BERING SEA MOVING SOUTH WHILE A LOW OVER
CHUKCHI SEA MOVES TO NEAR ANCHORAGE SUN EVENING. NORTHERN BRANCH OF
JET STREAM ATOP RIDGE OVER NORTHERN BERING AND SOUTHWEST AK WILL
ALSO MOVE SOUTH OVER WEEKEND.

SURFACE...FRONTAL SYSTEM FROM LISBURNE TO GALENA TO UNALAKLEET TO
THE SOUTHERN BERING STRAIT MOVING TO LISBURNE TO BETTLES TO DENALI
PARK TO TALKEETNA TO GAMBELL 4AM SAT WITH PORTION NORTH OF DENALI
PARK BEGINNING TO WEAKEN. THE FRONT WILL CONTINUE TO DRIFT SOUTH
OVER WESTERN ALASKA. 1008 MB LOW NEAR LISBURNE WILL SPLIT IN TWO
WITH ONE PORTION STATIONARY THROUGH 4PM SAT WHILE THE OTHER MOVING
TO NEAR FORT YUKON AT THAT TIME. THIS LOW WILL DRIFT SOUTH AND
DISSIPATE THOUGH A TROUGH WILL FORM FROM MAYO IN CANADA TO
ANCHORAGE SUN AM.

MODELS...IN SHORT TERM MODELS AGREE FAIRLY WELL THOUGH SOME
DIFFERENCE IN THE POSITION OF THE UPPER LOW AFTER 36 HOURS...WILL
FAVOR THE GFS ON THIS AS IT HOLDS THE LOW FARTHER WEST AND CLOSER
TO THE POOL OF COLD AIR ALOFT WHICH SEEMS MORE REASONABLE. IN THE
MEDIUM RANGE THE RMOP IS SHOWING IMPROVED PREDICTABILITY FOR THE
ONLY DAY 6 AND 7 WITH A RIDGE BUILDING OVER THE FAR EASTERN
ALASKA WITH A TROUGH OVER WESTERN ALASKA.

NORTH SLOPE...EAST WINDS CONTINUING AND TAPERING OFF A BIT AFTER
THIS EVENING BUT NOT BY MUCH. AS THE LOW PRESSURE CENTER MOVES
SOUTHEAST OF LISBURNE INTO THE INTERIOR WINDS WILL BE MORE
NORTHEAST AND DROP OFF SOME ON SUNDAY. EXPECT COASTAL FOG TO
PERSIST THROUGH THE WEEKEND WITH SOME AFTERNOON AND EARLY EVENING
IMPROVEMENT.

WESTERN ALASKA...RAIN OVER INTERIOR SECTIONS TONIGHT BECOMING
SCATTERED SHOWERS IN THE NORTH SAT. ISOLATED TO SCATTERED SHOWERS
OVER NORTHERN COASTAL ZONES TONIGHT AND SATURDAY...THEN
DIMINISHING SAT EVE WITH HARDLY ANY SHOWERS SUN. OVER SOUTHERN
COASTAL ZONES MORE RAIN TONIGHT OR BY EARLY SAT...THEN DIMINISHING
SAT NIGHT. WESTERLY WINDS PRODUCING AN ABUNDANCE OF COASTAL FOG
TODAY AND TONIGHT...ON SATURDAY WINDS VEERING SOME SO THAT THEY
BECOME PREDOMINATELY NORTH SUNDAY...THEN EXPECT ONLY FOG ALONG
NORTHERN SHORES.

CENTRAL AND EASTERN INTERIOR...RAIN SPREADING EAST TO CHANDALAR-
FAIRBANKS BY SAT MORNING...CONTINUING TO ARCTIC VILLAGE TO FORT
YUKON TO CHICKEN TO NEAR THE TOK CUTOFF LATE SATURDAY AFTERNOON.
TO THE EAST OF THIS AREA EXPECT AFTERNOON ISOLATED THUNDERSTORMS
SATURDAY...BUT SPREAD OF FRONTAL CLOUDS WILL DAMP OUT CONVECTION
THERE BY EVENING. RAIN REMAINING MORE STEADY OVER ZONES 225 AND
WESTERN 226 SAT AND SATURDAY NIGHT...WHILE SLOWLY TRANSITIONING TO
SHOWERS SAT PM MOST OTHER ZONES. STILL SOMEWHAT SHOWERY ACROSS
THE AREA SUNDAY...THOUGH IT MAY BE UNSTABLE ENOUGH WITH SOME
PARTIAL CLEARING SUNDAY AFTERNOON TO PRODUCE ISOLATED
THUNDERSTORMS OVER ZONES 220 AND NORTHERN 224.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...NONE AS HUMIDITIES WILL REMAIN HIGH.

&&

.HYDROLOGY...PERHAPS SUN AND MON THERE IS POTENTIAL FOR EXCESSIVE
RAINFALL ON NORTH SLOPES OF ALASKA RANGE IN ZONES 227 225 AND WRN
226.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ210-PKZ220-PKZ230-PKZ235-PKZ240-
PKZ245.
&&

JL AUG 11