Blizzard in Alaska, March 19, 2007

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT MON MAR 19 2007

.DISCUSSION...
MODELS ARE SIMILAR IN THE LARGE SCALE. HOWEVER...THE GFS DID
INITIALIZE BETTER THAN THE NAM AND ALSO IS PROGRESSING BETTER THROUGH
THE FIRST 6 HOURS AS WELL.

UPPER LEVELS...LOW OVER SOUTH CENTRAL WITH A RIDGE IN THE EASTERN
BERING AND ALEUTIANS AND ANOTHER LOW SOUTHWEST OF SHEMYA. A STRONG
SHORT WAVE TO MOVE OUT OF THE LOW IN THE WESTERN NORTH PACIFIC AND
PUSH THE RIDGE INTO THE GULF TONIGHT EFFECTIVELY MOVING THE COLD LOW
OUT OF SOUTH CENTRAL ALASKA. THE SHORT WAVE TO RAMP UP A STRONG
CLOSED LOW SOUTH OF THE CENTRAL ALEUTIANS TONIGHT AND IT WILL TRACK
UP THE AKPEN TUESDAY NIGHT AND ACROSS THE GULF WEDNESDAY. A STRONG
JET IS ASSOCIATED WITH THIS LOW AS IT MOVES CLOSE TO THE ALEUTIANS
TONIGHT AND INTO SOUTHWEST ALASKA TUESDAY MORNING. THE MAIN BRUNT OF
ENERGY ACROSS TEH GULF AREA WITH THE LOW TO TRACK SOUTH AND EAST OF
SOUTH CENTRAL ALASKA TOWARD YAKUTAT AND THE PANHANDLE TUESDAY AND
TUESDAY NIGHT. IN THE MEANTIME...THE POLAR LOW DROPS OVER THE CHUKCHI
SEA WITH A BROAD TROUGH DEVELOPING OVER THE BERING AND THE MAINLAND
THURSDAY. THE LOW CONTINUE TO DRIFT SOUTH INTO THE ANADYR GULF
SATURDAY AND INTO THE MAINLAND SUNDAY. ALL THE WHILE MAINTAINING A
TROUGH OVER THE ENTIRE FORECAST AREA.

WEST OF THE ALASKA RANGE...A STRETCHED OUT FRONT OVER THE BERING SEA
CREATING SOME INTERESTING SURFACE WEATHER THIS MORNING AND AFTERNOON.
THE FRONT IS MOVING RATHER SLOWLY NORTH AND IS BETWEEN SAINT GEORGE
AND SAINT PAUL WITH VFR AT SAINT PAUL CURRENTLY AND BLIZZARD
CONDITIONS IN SAINT GEORGE. SOME FREEZING RAIN OVER THE ALASKA
PENINSULA AND STRONG WINDS THROUGHOUT THESE AREAS. THE FRONT WILL
DISSIPATE THIS EVENING AS A LOW MOVES OUT OF THE NORTH PACIFIC. THE
LOW WILL MOVE TOWARD COLD BAY WITH STRONG WINDS AND GOOD AMOUNTS OF
PRECIPITATION FROM THE ALASKA PENINSULA TO UNALASKA. EXPECT THE WINDS
TO BE STRONG INITIALLY OVER COLD BAY TO SOUTHWEST ALASKA TOMORROW.
THEREFORE...HAVE DECIDED TO ISSUE BLIZZARD WATCHES FOR ZONES 161 AND
181. DID NOT ISSUE FOR 185 SINCE...MAIN BRUNT OF THE WIND TO THE EAST
INITIALLY. IN ADDITION...WITH HIGH PRESSURE TO THE NORTH THE PRESSURE
GRADIENT TIGHTENS OVER THE GULF FOR STRONG WINDS THERE THROUGH
TOMORROW. AS THE LOW PASSES TO THE EAST OF COLD BAY TOMORROW
AFTERNOON...GOOD COLD AIR ADVECTION BEHIND IT CREATING MODERATE TO
STRONG NORTHWEST WINDS. THIS MAY BE THE TIME FOR DUTCH TO GET NEAR
BLIZZARD CONDITIONS. THE ONE FACTOR ACTING AGAINST THIS FACT IS THE
LACK OF MOISTURE BEHIND THE SYSTEM. WE DO NOT THINK AT THIS TIME
THERE WILL NOT BE ENOUGH PRECIP ACTIVITY TO WARRANT A BLIZZARD.
PRECIP TO CONTINUE OVER SOUTHWEST ALASKA...MAINLY BRISTOL BAY
AREA...THROUGH WEDNESDAY MORNING WITH PLENTY OF SNOWFALL EXPECTED
THERE. AFTER THE LOW DRAGS INTO THE GULF WEDNESDAY...PRECIPITATION
WILL BE ON THE DOWNSIDE AND WINDS WILL DIE DOWN OVER THE EASTERN
BERING. HIGH PRESSURE TO TAKE OVER THE BERING WITH LIGHT SHOWER
ACTIVITY THROUGH FRIDAY. A WEAK SYSTEM TO MOVE THROUGH THE BERING
SUNDAY.

EAST OF THE ALASKA RANGE...A WEAK SURFACE TROUGH OVER THE NORTHERN
GULF COAST TO DISSIPATE TONIGHT IN ADVANCE OF A FRONT WORKING TO
KODIAK ISLAND BY TOMORROW MORNING. THIS FRONT COMING OUT OF A NORTH
PACIFIC LOW NEAR DUTCH HARBOR TOMORROW MORNING. THE LOW TO TRACK
SOUTH OF THE AKPEN AND ACROSS KODIAK ISLAND TUESDAY NIGHT WITH THE
FRONT PUSHING ONSHORE. STRONG WINDS TO CROSS THE GULF AND PUSH INLAND
AS WELL. PLENTY OF PRECIPITATION TO REACH THE COASTAL LOCATIONS BY
EARLY TUESDAY EVENING. THOUGHT ABOUT A SNOW ADVISORY FOR KODIAK BUT
BELIEVE SNOW WILL CHANGE OVER TO RAIN EARLY TUESDAY AFTERNOON WITH A
RAIN SNOW MIX. WITH THE PRECIP AND WIND EXPECTED TO REACH SOME INLAND
LOCATIONS TUESDAY NIGHT...HAVE ISSUED A BLIZZARD WATCH FOR ZONE 125.
IN ADDITION...EXPECT PLENTY OF SNOW TO FALL NEAR KACHEMAK BAY DURING
THIS STORM AS WELL. THOUGHT ABOUT A BLIZZARD WATCH FOR THOMPSON
PASS...BUT NOT CONVINCED ENOUGH PRECIP WILL BE AVAILABLE TO BLOW
AROUND. ANCHORAGE WILL LIKELY BE OUT OF THE PRECIP DUE TO DOWNSLOPE
EFFECTS FROM THE LOW TUESDAY NIGHT. THE LOW WILL WEAKEN DRAMATICALLY
WEDNESDAY AFTERNOON AND EVENING AS IT MOVES INLAND WITH PRECIP AND
WINDS ON A DRAMATIC DOWNTURN.  HOWEVER...THIS WILL BE THE TIME
ANCHORAGE AND SURROUNDING AREAS MAY SEE SNOWFALL. A SHORT WAVE TO
PUSH THROUGH THE MAINLAND BEHIND THE LOW WEDNESDAY NIGHT INTO
THURSDAY AND WILL LIKELY WRING OUT ANY ADDITIONAL MOISTURE OVER SOUTH
CENTRAL AT THAT TIME. ANOTHER LOW TO MOVE INTO THE GULF FRIDAY WITH
PRECIPITATION WRAPPING AROUND THE GULF FRIDAY. THE LOW MOVES INLAND
SATURDAY WITH PRECIP SPREADING OVER SOUTH CENTRAL. THE LOW WEAKENS
SATURDAY NIGHT WITH SCATTERED SNOW SHOWER ACTIVITY SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH ZONE 125 161 181
         SNOW ADVISORY 121 171
MARINE...GALE 120 125 130 132 138 140 141 155 160 165 170 172 176 179
         HEAVY FREEZING SPRAY 121 125 129 130 138 141 165 179
FIRE WEATHER...NONE

JN MAR 07