Blizzard in Alaska, February 13, 2014

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
521 AM AKST THU FEB 13 2014

.ANALYSIS AND UPPER LEVELS...

THE DOMINANT CENTER OF ACTION ON THE WEATHER MAP IS A DEEP AND
EXPANSIVE UPPER LEVEL LOW PREPARING TO ANCHOR ITSELF BY THIS
AFTERNOON OVER THE NORTHWESTERN GULF AND SPIN DISTURBANCES AROUND IT
WELL INTO NEXT WEEK. WITH SUCH COLD AIR ALOFT AND RELATIVELY WARM
GULF WATERS...PRECIPITATION HAS BEEN MAINLY SHOWERY THUS FAR OVER
SOUTHCENTRAL AND THE GULF OF ALASKA AND WILL LIKELY CONTINUE THAT
WAY.

OUT WEST...A STRONG RIDGE ALOFT OVER THE FAR WESTERN ALEUTIANS WILL
BE SHUNTED SOUTH AND EAST AS A STRONG WESTERLY JET STREAK JUST SOUTH
OF THE ALEUTIAN CHAIN USHERS ZONAL FLOW THE SOUTHERN BERING AND
ALEUTIAN RANGE FOR THE WEEKEND.

.MODEL DISCUSSION...

MODELS ARE IN GOOD AGREEMENT SYNOPTICALLY. WHERE MODELS CONTINUE TO
STRUGGLE IS WITH STRENGTH...TIMING...LOCATION...AND ORIENTATION OF
THE NUMEROUS SHORTWAVE DISTURBANCES ROTATING AROUND THE EXTREMELY
ACTIVE UPPER LEVEL LOW. THIS MAKES A GENERAL BROAD BRUSH FORECAST FOR
MOST OF THE SOUTHERN ALASKA REGION THE BEST METHOD OF FORECASTING
PAST THE FIRST PERIOD.

.SHORT TERM FORECAST...

SOUTHCENTRAL...

LIGHT SNOW SHOWERS MOVED ACROSS ANCHORAGE LAST EVENING...THEN
DISSIPATED NEAR TOWN WHILE CONTINUING MOST OF THE NIGHT TOWARD THE
PALMER AREA. EXPECT SNOW SHOWERS TO RESUME ACROSS THE ANCHORAGE AREA
AND THE REST OF THE POPULATION CENTERS NORTH AND WEST OF THE
CHUGACH/KENAI RANGE THROUGH LATE MORNING AND POSSIBLY PERSIST INTO
EARLY AFTERNOON BEFORE DIMINISHING. TOWARD THE PRINCE WILLIAM SOUND
AREA...MODELS HAVE CORRECTLY PICKED UP ON THE NEXT WAVE WHICH WILL
PUSH A NEW ROUND OF SNOW SHOWERS NORTH INTO CORDOVA AND VALDEZ THIS
MORNING.

THIS SAME GENERAL IDEA WILL CONTINUE FOR THE NEXT SEVERAL DAYS...WITH
THE EXCEPTION BEING THAT THE SYSTEMS APPROACHING THE EASTERN PRINCE
WILLIAM SOUND AND COPPER RIVER BASIN FROM THE SOUTH WILL BECOME
STRONGER AND HAVE MUCH BETTER DYNAMICS ALOFT. WE WILL NEED TO WATCH
FOR THE POTENTIAL FOR PERIODS OF HEAVY SNOW IN THESE AREAS FOR THE
WEEKEND.

SOUTHWEST ALASKA...

VERY COLD ARCTIC AIR AND GUSTY NORTHERLY WINDS WILL CONTINUE TO
SUPPORT DANGEROUS WIND CHILL CONDITIONS THROUGH FRIDAY AS THE UPPER
LOW DROPS ALONG THE ALEUTIAN RANGE AND INTO THE WESTERN GULF GULF OF
ALASKA. ALTHOUGH MOST OF THE AREA WILL REMAIN DRY...A SERIES OF
DISTURBANCES ROTATING AROUND THE WESTERN PERIPHERY OF THE LOW WILL
BRING A FEW SNOW SHOWERS TO COASTAL PORTIONS OF THE KUSKOKWIM DELTA
TODAY. TEMPERATURES WILL REBOUND SLIGHTLY BY THIS WEEKEND AND ALLOW
WIND CHILL VALUES TO IMPROVE SOMEWHAT...ALTHOUGH PERSISTENT OFFSHORE
FLOW WILL KEEP GENERALLY COLD AND DRY CONDITIONS OVER THE REGION INTO
THE EXTENDED TERM...WITH VERY COLD WIND CHILL VALUES REMAINING A
CONCERN THROUGH THE COMING DAYS.

BERING SEA AND ALEUTIANS...

CONVECTIVE SNOW SHOWERS LOOK TO INCREASE IN COVERAGE AND INTENSITY
TODAY ACROSS THE EASTERN BERING AS ARCTIC AIR CONTINUES TO FILTER
INTO THE REGION. THESE SNOW SHOWERS WILL COMBINE WITH INCREASING
NORTHERLY WINDS TO PRODUCE WIDESPREAD AREAS BLOWING SNOW AND REDUCED
VISIBILITIES. THE WORST CONDITIONS ARE EXPECTED TO DEVELOP BY EARLY
THIS AFTERNOON ALONG THE ALASKA PENINSULA...WHERE A BLIZZARD WARNING
HAS BEEN ISSUED THROUGH FRIDAY MORNING. FURTHER WEST...A WINTER
WEATHER ADVISORY FOR BLOWING SNOW HAS BEEN ISSUED FOR THE EASTERN
ALEUTIANS AS DUTCH HARBOR LOOKS TO REMAIN ON THE WESTERN PERIPHERY OF
THE STRONGEST WINDS AND MOST INTENSE SNOW SHOWER ACTIVITY AND THUS
VISIBILITIES ARE EXPECTED TO REMAIN A LITTLE HIGHER THAN THOSE ALONG
THE AKPEN. BLOWING SNOW WILL ALSO IMPACT THE PRIBILOF ISLANDS
ALTHOUGH VISIBILITIES ARE EXPECTED TO REMAIN ABOVE ADVISORY/WARNING
CRITERIA. ELSEWHERE...A WEAK FRONT MOVING INTO THE WESTERN BERING
WILL BRING SNOW AND RAIN SHOWERS TO THE WESTERN AND CENTRAL ALEUTIANS
THROUGH THE END OF THE WEEK.

.LONG TERM FORECAST...

FORECAST CONFIDENCE REMAINS HIGHER THAN NORMAL GOING INTO THE
EXTENDED TERM AS THE DEEP UPPER LOW CURRENTLY OVER THE SOUTHWEST
MAINLAND WILL REMAIN ANCHORED OVER THE NORTHWESTERN GULF OF ALASKA
WELL INTO NEXT WEEK. THIS WILL GENERALLY CONTINUE TO YIELD COLD
TEMPERATURES AND GUSTY OUTFLOW WINDS OVER THE SOUTHERN HALF OF THE
MAINLAND...WITH THE BEST CHANCE FOR PRECIPITATION REMAINING ALONG THE
NORTHERN GULF COAST. PRECIPITATION CHANCES FURTHER INLAND WILL
CONTINUE TO DEPEND ON THE EXACT POSITION/STRENGTH OF THE PARENT LOW
AND THE VARIOUS WAVES ROTATING AROUND IT. MEANWHILE...A MORE ACTIVE
PATTERN WILL BE IN STORE FOR THE BERING AS UPPER LEVEL RIDGING OVER
THE WESTERN BERING BREAKS DOWN AND SEVERAL DISTURBANCES MOVE THROUGH
AND PROVIDE OCCASIONAL CHANCES FOR PRECIPITATION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING...181
         WINTER WEATHER ADVISORY FOR BLOWING SNOW...131 185
         WIND CHILL ADVISORY...131 152 155 161
MARINE...GALES...127 130-132 150 155 160 165 170-172 174 176-181
         HVY FRZG SPRY...121 126 127 129 130-132 136-141 150 155 160
                         165 170 179 180 185
FIRE WEATHER...NONE.

CC/CB FEB 14