Gale Warning 58, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
345 AM AKST WED JAN 8 2014

.ANALYSIS AND UPPER LEVELS...

THE UPPER AIR PATTERN REMAINS CONVOLUTED OVER MOST OF THE REGION THIS
MORNING AS ALASKA AND THE BERING SEA REMAIN SANDWICHED BETWEEN THE
PACIFIC JET TO THE SOUTH...AND A BROAD BLOCKING HIGH SITUATED
NORTHWEST OF WRANGEL ISLAND AND THE SIBERIAN SEA. AN ELONGATED UPPER
LOW EXISTS OVER THE BERING SEA...STRETCHING SOUTHEAST INTO THE GULF
OF ALASKA. A WELL DEFINED UPPER ANOMALY CAN BE SEEN ON WATER VAPOR
SATELLITE JUST EAST OF KODIAK ISLAND...WITH AN ASSOCIATED SURFACE LOW
OVER THE NORTHERN GULF. CENTERED OVER THE DATELINE...A BROAD UPPER
TROUGH IS TRANSLATING EAST... WITH A LEADING SHORTWAVE TROUGH
TRACKING NORTHEAST TOWARD THE PANHANDLE.

EVENTUALLY...THE UPPER LOW OVER THE NORTHERN GULF WILL SLOWLY TRACK
INTO PRINCE WILLIAM SOUND...WITH NUMEROUS OTHER WEAK WAVE
DISTURBANCES TRACKING OVER SOUTHERN ALASKA THROUGH THE END OF THE
WEEK AS THE LONGWAVE TROUGH COMPLEX TRANSLATES EAST. WHILE THE STORM
TRACK WILL REMAIN WELL TO THE SOUTH OF ALASKA...THIS PATTERN WILL
KEEP SOUTHERN ALASKA UNDER THE THREAT OF PERIODIC SNOW SHOWERS WITH
COLDER AIR SLOWLY INFILTRATING FROM THE NORTH.

.MODEL DISCUSSION...

NO CHANGE FROM YESTERDAY AS THE NUMERICAL MODELS REMAIN IN EXCELLENT
AGREEMENT SYNOPTICALLY THROUGH THE WEEKEND. THEY CONTINUE TO DIVERGE
WITH RESPECT TO NUMEROUS LOW AMPLITUDE WAVES EMBEDDED WITHIN THE
OVERALL UPPER FLOW...ESPECIALLY BEYOND SATURDAY. THE FORECAST WILL
CONTINUE TO FAVOR THE GFS AND ECWMF AS THEY REPRESENT THE MOST STABLE
SOLUTIONS HEADING INTO THE WEEKEND.

NEXT WEEK...THE GLOBAL GUIDANCE IS SHOWING QUITE A BIT OF UNCERTAINTY
WITH RESPECT TO THE EXACT POSITION OF A SHARP BAROCLINIC ZONE...AND A
LARGE VORTEX OVER ALASKA (SEE EXTENDED DISCUSSION).

.SHORT TERM FORECAST...

SOUTHCENTRAL...
PRECIPITATION CHANCES WILL INCREASE ACROSS MOST OF SOUTHCENTRAL
ALASKA THIS MORNING. ALONG THE COAST...A RAIN AND SNOW MIX WILL BE
OBSERVED WHILE INLAND AREAS INCLUDING ANCHORAGE AND THE MAT-SU VALLEY
WILL HAVE A GOOD CHANCE OF SEEING MEASURABLE SNOW LATE THIS AFTERNOON
INTO THIS EVENING. PRECIPITATION WILL TAPER OFF BY THURSDAY
MORNING...WITH SCATTERED SNOW SHOWERS RESIDING IN THE COPPER RIVER
BASIN. TEMPERATURES WILL CONTINUE TO GRADUALLY COOL DOWN THROUGH THE
REMAINDER OF THE WEEK...WITH TEMPERATURES RETURNING TO NEAR NORMAL
VALUES. PERIODIC LIGHT SNOW SHOWERS WILL BE A THREAT ACROSS MOST OF
SOUTHCENTRAL THROUGH THE END OF THE WEEK.

SOUTHWEST...
THE REGION WILL CONTINUE TO SEE PERIODS OF LIGHT RAIN AND SNOW
SHOWERS HEADING INTO THE WEEKEND AS NUMEROUS WAVE DISTURBANCES TRACK
THROUGH THE AREA. SOME LIGHT SNOW ACCUMULATIONS WILL DEVELOP ALONG
THE ALEUTIAN AND ALASKA RANGES TODAY...OTHERWISE ACTIVITY WILL
GENERALLY REMAIN SCATTERED. LOCAL AREAS OF PATCHY FOG WILL DEVELOP
THIS EVENING.

BERING SEA AND ALEUTIANS...
RAIN AND SNOW SHOWERS WILL CONTINUE OVER THE AREA THROUGH THURSDAY. A
STRONG LOW WILL MOVE INTO THE WESTERN ALEUTIANS ON FRIDAY...WITH A
FRONT TRACKING OVER THE CENTRAL AND EASTERN ALEUTIANS...BRINGING MORE
RAIN AND SNOW. STRONGER MAX GALE FORCE SOUTHWEST WINDS WILL IMPACT
THE CENTRAL ALEUTIANS AS THE LOW SLOWLY TRACKS EAST INTO SATURDAY.

.LONG TERM FORECAST...

BY SATURDAY...TEMPERATURES WILL HAVE MODERATED BACK TO NEAR NORMAL
OVER SOUTHERN ALASKA...WITH A CONTINUED STORM TRACK SOUTH OF THE
AREA. THE GLOBAL GUIDANCE IS HINTING AT A MORE ACTIVE PATTERN
POSSIBLY DEVELOPING SUNDAY INTO EARLY NEXT WEEK AS NUMEROUS FAST
MOVING WAVES BREAK OFF THE PACIFIC JET STREAM. THE PATTERN ALOFT
WOULD LIKELY KEEP PRECIPITATION AS SNOW...ALTHOUGH IT IS IMPOSSIBLE
TO TRACK OR TIME THE INDIVIDUAL WAVES AT THIS JUNCTURE. THE BIGGER
STORY CONTINUES TO BE THE POTENTIAL FOR A SIGNIFICANT CHINOOK EVENT
LATE IN THE WEEK AS A POWERFUL 210+ KNOT EAST ASIAN PACIFIC JET
STREAM BUCKLES AND AMPLIFIES SOUTH OF THE ALEUTIAN CHAIN. SUCH A
SCENARIO WOULD SUGGEST THE POTENTIAL FOR A MAJOR WARM-UP ACROSS
SOUTHERN ALASKA...SIGNIFICANT STORMINESS ACROSS THE BERING...AND
HEAVY RAINFALL ALONG THE GULF COAST. DETAILS...HOWEVER...REMAIN QUITE
UNCERTAIN.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 172-174 176-178 185.
         HEAVY 185.
FIRE WEATHER...NONE.

AHSENMACHER/CLAY JAN 14