High Surf Advisory 2, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
450 AM AKDT WED AUG 26 2015

.SYNOPSIS...
ALOFT...
THE LONG WAVE TROUGH STRETCHING FROM THE WRANGEL ISLAND TO THE
WESTERN BERING SEA INTO THE NW PACIFIC WILL PROGRESS EAST OVER
MAINLAND AK THU AND THEN PERSIST INTO NEXT WEEK. STRONG SW FLOW
ON THE EAST SIDE OF THE LONG WAVE TROUGH CONTINUES TO PUSH AIR
WITH 3 TIMES THE NORMAL PRECIPITABLE WATER OVER NORTHERN ALASKA.
THIS ADDITIONAL MOISTURE WAS FED INTO THE EAST SIDE OF THE TROUGH
BE A FORMER TYPHOON DISSIPATING THE NW PACIFIC. THIS HIGH MOISTURE
AIR WILL CONTINUE TO CAUSE HEAVY RAIN OVER NORTHERN ALASKA THROUGH
THU WITH SOUTH AND WEST FACING SLOPES GETTING THE HIGHEST AMOUNTS.
SEVERAL STRONG SHORT WAVES AND THEIR ASSOCIATED FRONTAL WAVES WILL
CAUSE ENHANCED RAINFALL THROUGH THU. FROM FRIDAY INTO NEXT WEEK
EXPECT COOL AND WET CONDITIONS...BUT PRECIPITATION WILL NOT BE AS
HEAVY.

A STRONG SHORT WAVE ALONG THE WEST COAST OF ALASKA WILL MOVE TO
ANAKTUVUK TO DENALI BY 4PM WED AND EAST OF THE ALCAN BORDER WED
NIGHT. A STRONG SURFACE FRONTAL WAVE IS ASSOCIATED WITH THIS ALONG
WITH HEAVY RAIN AND SW WINDS GUSTING TO 30 KT.

850 MB TEMPERATURES RANGE FROM 4 TO8C NOW. TEMPERATURES WILL FALL
TO 0C TO -4C OVER NW AK THIS AFTERNOON BEHIND THE COLD
FRONT...WITH THIS COLD AIR SPREADING OVER THE REST OF NORTHERN
ALASKA THU WITH THE COLD FRONT. THIS WILL LOWER THE SNOW LEVEL TO
1000-2000 FEET BEHIND THE COLD FRONT THU.

SURFACE...
A 987 MB LOW 150 NM NORTHWEST OF BARROW WILL MOVE TO 170 NM
NORTHWEST OF BARROW BY 4PM WED...TO 150 NM NORTH OF BARROW BY 4AM
THU...TO 200 NM NORTH OF BARROW BY 4PM THU...AND TO 150 NM NORTH
OF BARROW BY 4PM FRI. GALES FORCE W WINDS IN THE SW QUADRANT OF
THIS LOW WILL MOVE OVER THE ARCTIC COAST FROM BARROW WEST WED
NIGHT AND TO THE EASTERN ARCTIC THU. THIS WILL CAUSE HIGH SURFACE
FROM BARROW WEST TONIGHT AND THU WITH SEA LEVEL RISE OF 1-2 FT.
SINCE THERE IS SEA ICE BETWEEN BARROW AND PRUDHOE BAY DO NOT
EXPECT HIGH WAVES OR ELEVATED SURF EAST OF BARROW. MAY SEE SEA ICE
PUSH ALONG THE COAST FROM PRUDHOE BAY EAST AS A RESULT OF THESE
WINDS BUT ONLY LIMITED SURF DUE TO DAMPENING BY THE SEA ICE.

A A 995 MB FRONTAL WAVE IN THE BERING STRAIT WILL MOVE TO
GALBRAITH LAKE AS A 994 MB LOW BY 4PM WED AND TO INUVIK AS A 991
MB LOW BY 4AM THU. A WARM FRONT EXTENDING EAST OF THIS LOW.
A COLD FRONT EXTENDING SOUTH OF THE LOW WILL MOVE TO ANAKTUVUK
PASS TO DENALI BY 4PM WED...TO OLD CROW TO CIRCLE TO BIG DELTA BY
4AM THU...AND EAST OF THE ALCAN BORDER BY NOON THU. WILL SEE HEAVY
RAIN ALONG THE FRONTAL WAVE AND ALONG THE WARM AND COLD FRONTS.
EXPECT ANOTHER 0.5-1.5 INCHES OF RAIN TO SPREAD EAST ACROSS
NORTHERN ALASKA WITH THIS SYSTEM...WITH THE HEAVIEST AMOUNTS ALONG
SOUTH AND WEST FACING SLOPES. RAIN WILL BECOME LIGHT WEST OF THE
COLD FRONT. EXPECT THIS TO CAUSE FLOODING OF SMALL STREAMS ZONES
208 210 211 212 217 WITH LARGE RIVERS RISING TO HIGH LEVELS BUT
NOT FLOODING. THIS COULD CAUSE SMALL STREAMS TO FLOOD IN STEEP
TERRAIN OF THE INTERIOR SUCH AS SOUTH SLOPES OF THE CENTRAL BROOKS
RANGE...THE WESTERN ALASKA RANGE...AND THE CHENA AND SALCHA
BASINS SO WILL NEED TO KEEP EYE ON THOSE AREAS.

ARCTIC COLD FRONT OVER THE DATELINE WILL MOVE TO JUST EAST OF
BARROW TO NOME TO GAMBELL BY 4PM WED...TO DEMARCATION POINT TO
COLD FOOT TO THE YUKON DELTA BY 4AM THU...TO ARCTIC VILLAGE TO
NORTHWAY BY 4PM THU...THEN CONTINUING EAST. EXPECT RAIN EAST OF
THE FRONT TAPERING OFF TO SCATTERED SHOWERS NORTHWEST OF THE
FRONT. SNOW LEVEL WILL DROP TO 1000-2000 FEET NW OF THE FRONT.
EXPECT 2-6 INCHES OF SNOW ACROSS THE EASTERN BROOKS RANGE TONIGHT
THROUGH LATE THU...HEAVIEST ABOVE 2000 FT. WILL ISSUE WINTER
STORM WATCH FOR ZONE 206. EXPECT 2-4 INCHES IN THE ALASKA RANGE
ABOVE 3000 FT THU-THU NIGHT.

&&

.DISCUSSION...
MODELS INITIALIZE WELL AND SHOW SIMILAR SOLUTION THROUGH THU.
START TO SEE MODELS DIVERGE ON FRI WITH TIMING AND STRENGTH OF
SHORT WAVE TROUGHS BUT ALL MODELS KEEP LONG WAVE TROUGH OVER
MAINLAND ALASKA INTO NEXT WEEK. PREFER THE GFS PRECIP AMOUNTS
WHICH ARE HEAVIER THAN THE NAM ANS ECMF FOR TODAY BUT VERIFY
BETTER AT 06Z.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...
HIGH SURF ZONES 213 AND 207 NOW ENDING.
HIGH SURF 211 AND 212 WILL CONTINUE THROUGH THU.
HIGH SURF ZONES 201 AND 202 FROM THIS AFTERNOON TO 10 PM THU.

MODERATE SURF ZONES 203 AND 204 THU AND THU NIGHT WITH POTENTIAL
FOR ICE RAFTING ONSHORE.

MODERATE SURF ZONE 207 AT SHISHMAREF TONIGHT THROUGH THU.
POTENTIAL FOR HIGH SURF 207 AT SHISHMAREF THIS WEEKEND.

&&

.FIRE WEATHER...
NONE.

&&

.HYDROLOGY...
HAVE HAD 1.0-2.5 INCHES OF RAIN ACROSS THE WEST COAST AND NW
INTERIOR AND .5-1.5 INCHES ACROSS REMAINDER OF AREA FROM BROOKS
RANGE SOUTH. EXPECT ANOTHER 0.5-1.5 INCHES OF RAIN TO SPREAD EAST
ACROSS NORTHERN ALASKA WITH THIS SYSTEM...WITH THE HEAVIEST
AMOUNTS ALONG SOUTH AND WEST FACING SLOPES. RAIN WILL BECOME LIGHT
WEST OF THE COLD FRONT. EXPECT THIS TO CAUSE FLOODING OF SMALL
STREAMS ZONES 208 210 211 212 217 WITH LARGE RIVERS RISING TO HIGH
LEVELS BUT NOT FLOODING. THIS COULD CAUSE SMALL STREAMS TO FLOOD
IN STEEP TERRAIN OF THE INTERIOR SUCH AS SOUTH SLOPES OF THE
CENTRAL BROOKS RANGE...THE WESTERN ALASKA RANGE...AND THE CHENA
AND SALCHA BASINS SO WILL NEED TO KEEP EYE ON THOSE AREAS.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ222.

HIGH SURF ADVISORY FOR AKZ201-AKZ202-AKZ211-AKZ212-AKZ214.

FLOOD WATCH FOR AKZ210-AKZ211-AKZ212.

SMALL STREAM FLOOD ADVISORY ZONES 210 217

WINTER STORM WATCH FOR AKZ206.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ230-PKZ235-PKZ240-PKZ245.

GALE WARNING FOR PKZ225-PKZ230-PKZ235.

&&

JB AUG 15