Small Craft Advisory 66, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ANCHORAGE AK
910 PM AKST MON JAN 20 2014

UPDATE FOR SOUTHCENTRAL SHORT-TERM FORECAST...

A MID-LVL DISTURBANCE AROUND 350 MILES SOUTHEAST OF SEWARD WILL TRACK
NORTH-NORTHWEST THE NEXT 12-HOURS. THIS FEATURE WILL LIKELY WEAKEN AS
IT MOVES ASHORE DURING THE OVERNIGHT HOURS AS IT SEEMS TO LACK MUCH
JET SUPPORT IN THE FLOW. GIVEN THAT AREA TEMPERATURES ARE HOVERING AT
OR BELOW FREEZING ACROSS LOW LYING AREAS OF THE ANCHORAGE BOWL WITH A
PRONOUNCED WARM LAYER ALOFT...PERIPHERAL PRECIPITATION WITH COULD
INCLUDE A BRIEF PERIOD OF FREEZING RAIN. AS SUCH HAVE INCLUDED
ISOLATED POCKETS AFTER MIDNIGHT. IT IS UNCLEAR JUST HOW MUCH QPF WILL
FALL WITH THIS FAST MOVING DISTURBANCE...AND THE WESTERN PERIPHERY OF
IT'S PRECIPITATION SHIELD COULD STAY MAINLY EAST OF THE CHUGACH/KENAI
RANGE.

OVERALL...LOW LEVEL TEMPERATURES ARE STILL EXPECTED TO BE WARMING
THROUGH TUE...SUPPORTIVE OF COLD RAIN AND PERHAPS SOME MIXING WITH
WET SNOW TUE EVENING.

UPDATE...JAM

.ANALYSIS AND UPPER LEVELS...

HIGHLY AMPLIFIED WEATHER PATTERN REMAINS IN PLACE FOR THE FORESEEABLE
FUTURE...WITH PERSISTENT STRONG UPPER LEVEL RIDGING CONTINUING ALONG
THE WEST COAST OF NORTH AMERICA AND EXTENDING NORTH AND WEST THROUGH
NORTHERN AND INTERIOR ALASKA AND A PERSISTENT LONGWAVE TROUGH
OCCUPYING THE BERING AND ADJACENT NORTHERN PACIFIC. BETWEEN THE TWO
CENTERS OF ACTION...DEEP SOUTHERLY FLOW CONTINUES TO PUSH A
SUBTROPICAL AIR MASS INTO SOUTHERN ALASKA.

IN THE SHORT TERM...A TRIO OF UPPER LEVEL DISTURBANCES WILL MOVE
NORTH INTO THE STATE FROM THE PACIFIC OVER THE NEXT 24 TO 36
HOURS...ALL WHILE A SURFACE LOW OVER THE EASTERN BERING WEAKENS AS IT
MOVES NORTHWEST TOWARD THE FAR NORTHWEST BERING AND SIGNIFICANTLY
WEAKENS BY WEDNESDAY AFTERNOON.

FOR WEDNESDAY AND THURSDAY...A STRONG WEATHER FRONT MOVES NORTH AND
BRINGS A RENEWED PUSH OF WARM AIR INTO THE STATE AND BRINGS A RENEWED
PUSH OF RAIN ACROSS MOST AREAS OF THE SOUTHERN MAINLAND.

.MODEL DISCUSSION...

MODELS ARE GOOD AGREEMENT...WITH VERY LITTLE IF ANY SIGNIFICANT
DIFFERENCE BETWEEN THE GFS AND EURO (EC) MODEL RUNS. THE NAM IS ALSO
USEFUL FOR THE FIRST 24 HOURS OF THE FORECAST PERIOD.

.SHORT TERM FORECAST...

SOUTHCENTRAL...

A NEARLY STATIONARY BAND OF RAIN WILL CONTINUE TO IMPACT THE KODIAK
AREA THROUGH TONIGHT...ENDING AS YET ANOTHER STRONG FRONT MOVES NORTH
TOWARD THE GULF COAST TUESDAY MORNING. RAIN WILL BE CONFINED TO THE
GULF COAST AND SOUTHWESTERN KENAI PENINSULA UNTIL THAT TIME...BUT
WITH TROUGH PASSAGE DYNAMICS WILL BE STRONG ENOUGH TO GENERATE STEADY
PRECIPITATION INLAND TUESDAY AFTERNOON FROM ANCHORAGE AND PALMER TO
TALKEETNA...WITH A CHANGEOVER TO POTENTIALLY SIGNIFICANT HEAVY WET
SNOW ACCUMULATIONS FOR PORTIONS OF THE SUSITNA VALLEY. TEMPERATURES
ARE LIKELY TO HIT THE MID TO UPPER 30S ACROSS ANCHORAGE AND PALMER
BEFORE RAIN ARRIVES...BUT WITH WEAK COLD ADVECTION ALOFT
PRECIPITATION COULD END AS A VERY BRIEF PERIOD OF WET SNOW OR SNOW
GRAINS.

STRONG WINDS WILL ALSO IMPACT THE GULF COAST...WITH A FAVORABLE WIND
ORIENTATION FOR THE CORDOVA BOAT HARBOR TO BE IMPACTED AS THE BARRIER
JET FORMS ALONG THE GULF COAST LATE TONIGHT INTO TUESDAY.

SOUTHWEST...

A STRONG BAND OF PRECIPITATION LINED UP WITH A POWERFUL JET STREAK
AND WINDS ALOFT WILL SLOWLY PUSH NORTH OVER THE BRISTOL BAY REGION OF
ALASKA THROUGH TONIGHT BEFORE SLOWLY WEAKENING INTO TUESDAY MORNING.
UNUSUALLY STRONG WINDS WILL ALSO OCCUR IN THE KUSKOKWIM VALLEY AS
WELL TONIGHT...WITH RAIN FALLING AND POTENTIALLY MIXING WITH FREEZING
RAIN IN THE MOST SHELTERED VALLEYS ALONG THE KUSKOKWIM RIVER THIS
EVENING.

AS ANOTHER STRONG DISTURBANCE MOVES NORTH ACROSS THE SOUTHWESTERN
MAINLAND TOMORROW...ANOTHER ROUND OF RAIN WILL OCCUR...CHANGING OVER
TO OR MIXING WITH SNOW ALONG THE BACK EDGE AS COOLER AIR MOVES IN
ALOFT BEHIND THE DISTURBANCE BEFORE PRECIPITATION ENDS.

BERING SEA...

SNOW SHOWERS WILL CONTINUE OUT IN THE WESTERN AND CENTRAL
ALEUTIANS...WARMING TO RAIN SHOWERS THE FURTHER EAST ONE GOES. ALONG
THE BATTLE LINES BETWEEN THE TWO AIR MASSES...THE PRIBILOFS CONTINUE
TO SEE NEAR BLIZZARD CONDITIONS AS LOW PRESSURE MOVES BY TO THE NORTH
AND EAST. CONDITIONS WILL IMPROVE GRADUALLY OVERNIGHT AS THE
STRONGEST TEMPERATURE GRADIENT BEGINS TO SLACKEN...BUT AN APPROACHING
SYSTEM WILL AGAIN THREATEN THE EASTERN ALEUTIANS AND PRIBILOFS WITH
POTENTIAL BLIZZARD CONDITIONS BY WEDNESDAY AND WEDNESDAY NIGHT...WITH
RAIN TO THE EAST.

.LONG TERM FORECAST...

THE WARM AND WET WEATHER PATTERN PERSISTS THROUGH NEXT WEEKEND WITH
NO CLEAR END IN SIGHT. TEMPERATURES WILL CONTINUE TO AVERAGE 10 TO 15
DEGREES ABOVE NORMAL ON AVERAGE WITH GREATER THAN NORMAL CHANCES FOR
PRECIPITATION FROM LATE WEEK THROUGH THE WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING...161
         WINTER WEATHER ADVISORY BLOWING SNOW...195
MARINE...STORM...119 130
         GALE...120 131 132 136 137 150 155 160 165 170 172 179
                180 351 412
         HEAVY FREEZING SPRAY...185 411 412 413 414
FIRE WEATHER...NONE.

CC JAN 14