Heavy Freezing Spray Warning 33, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST TUE JAN 18 2011

.MODEL DISCUSSION...SOME IMPORTANT DIFFERENCES IN 00Z MODELS
AFTER 48 HOURS HANDLING LOWS MOVING NE FROM NPAC INTO GULF AK
IN BROAD MILD SWRLY FLOW ALOFT NEXT SEVERAL DAYS. GFS AND ECMWF
SHOW A WELL-DEFINED SURFACE LOW MOVING N TO JUST S OF PADQ FRI.
NAM JUST HAS A WEAK TROUGH. ECMWF IS STRONGER WITH THIS LOW AS
IT MOVES INTO NRN GULF FRI NIGHT AND ONSHORE NEAR PAYA SAT THAN
THE GFS...BUT BASED ON GFS SUPERIOR CONTINUITY LAST SEVERAL DAYS
HAVE OPTED TO USE IT PRIMARILY.

.ANALYSIS AND UPPER LEVELS...OLD DECAYING VERTICALLY STACKED LOW
SSE OF PASY HAS SPLITTING OCCLUDED FRONTAL SYSTEM ARCING WELL
AHEAD OVER AK PEN NOW...WITH TRIPLE POINT AND MAIN AXIS OF SWRLY
JET JUST S OF PADQ. WEAK 993 MB OR SO TRIPLE POINT LOW WILL FORM
IN NRN GULF AK THIS EVENING...BUT FRONT WILL RAPIDLY FALL APART
AS IT MOVES ONSHORE GULF COAST AND INLAND OVER S-CENTRAL/COPPER
RIVER BASIN TODAY/TONIGHT. GOES IR SHOWS A LARGE COMPLEX SHORT-WAVE
WELL SE OF OLD LOW S OF PASY WHICH WILL DEEPEN TO A 975 MB OR SO
SURFACE CENTER AS IT MOVES NE OVER THE ERN ALEUTIANS THU AFTERNOON
AND EVENING. WEAK FRONT WITH THIS WILL MOVE INTO WRN GULF THU NIGHT
AND NRN GULF/ERN GULF COAST EARLY FRI. IT WILL ALSO RAPIDLY FALL
APART AS IT MOVES INLAND FRI. ANOTHER QUICKLY FOLLOWING WAVE WILL
TRACK FROM S OF PADQ NE OVER NRN GULF AND ERN GULF COAST FRIDAY
NIGHT AND S-CENTRAL SAT. NEEDLESS TO SAY...MUCH WARMER CONDITIONS
ALL AREAS STARTING TODAY.

.SHORT TERM FORECAST...
SOUTH-CENTRAL/SOUTHWEST
BLIZZARD WARNING FOR 155 WAS CANCELLED...FRONT FROM ALEUTIANS LOW
IS SPLITTING AS IT MOVES N INTO WEAK RIDGING OVER SWRN AK MAINLAND.
THIS FRONT WILL BRING SOME BLIZ CONDITIONS TO 161 TODAY...NORTH AND
W OF PAKN...SO KEPT WARNING THERE FOR TODAY. FRONT WILL BRING SOME
-SN TO 152 LATER TODAY/TONIGHT...BUT MUCH LIGHTER AMOUNTS. NEXT
SYSTEM WILL BRING MIXED PRECIP TO AK PEN THU/THU NIGHT...AND SOME
SNOW TO MAINLY ZONES 152 AND 161 THU NIGHT AND FRI...ALONG WITH
VERY MILD AIR. WILL HAVE TO WATCH FOR -FZRA POTENTIAL EARLY FRI
ZONE 161 WITH THIS. FOR S-CENTRAL...SPLITTING FRONT WILL BRING SNOW
AS FAR N AS WRN SUSITNA VALLEY...WITH HEAVIEST AMOUNTS GULF COAST
AND KENAI. BLIZZARD WARNING ISSUED FOR PORTAGE VALLEY AND EASTERN
TURNAGAIN ARM UNTIL LATE AFTERNOON TODAY. EAST WINDS WILL BE STRONG
ENOUGH WITH THE FALLING SNOW TO BRING VISIBILITIES DOWN QUICKLY THERE.
A BREAK THU BETWEEN SYSTEMS...THEN MORE SNOW FOR S-CENTRAL FRI INTO
SAT...MIXING WITH RAIN GULF COAST AND KENAI.

BERING/ALEUTIANS
SHOWERS TODAY OVER ALEUTIANS WITH MUCH LIGHTER WINDS IN WAKE OF
STRONG OCCLUDED FRONT. NEXT FRONT/SURFACE LOW WILL BRING GALES
AND RAIN TO ERN ALEUTIANS THU...WITH JUST SHOWERS CENTRAL AND WRN
IN RESIDUAL UPPER TROUGHING.

.LONG TERM FORECAST...
BROAD MILD SWRLY UPPER FLOW WILL CONTINUE THROUGH THE WEEKEND. A
MUCH STRONGER SURFACE LOW WILL PUSH AN OCCLUDED FRONT N OVER CENTRAL
AN ERN ALEUTIANS AND WRN GULF AK SAT/SAT NIGHT. THIS FRONT WILL THEN
MOVE INTO NRN GULF EARLY SUN...AND INLAND OVER S-CENTRAL SUN...WITH
VERY MILD MARITIME AIR.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 161
MARINE...STORMS 411 412 130 138 140 160 185
         GALES...414 351 352 120 127 132 155 170 176 179 180
FIRE WEATHER...NONE.

MAR JAN 11