Blizzard and High Wind in Alaska, November 17 to 18, 2003

NORTH ALASKA FORECAST DISCUSSION
230 PM AST MON NOV 17 2003

.DISCUSSION...AT THE SURFACE...973 MB LOW OVER THE KAMCHATKA
PENINSULA AND 1006 MB LOW NORTHWEST OF POINT BARROW ARE PUTTING
THE SQUEEZE ON A SKINNY RIDGE BETWEEN THEM...EXTENDING NORTH FROM
NORTH PACIFIC 1044 MB HIGH SOUTH OF DUTCH HARBOR. KAMCHATKA
SYSTEM IS PUSHING WARM MOIST AIR BACK INTO THE BERING SEA...AND
AGAINST ARCTIC FRONT FROM GULF OF ANADYR TO NUNIVAK ISLAND. A
WEAK TROUGH FROM THE POINT BARROW LOW EXTENDS SOUTHWARD TO THE
NULATO HILLS...AND IS SPONSORING SOME FLURRIES AND ISOLATED SNOW
SHOWERS.
TIGHT SURFACE PRESSURE GRADIENT REFUSES TO LET UP OVER THE
CHUKCHI SEA COAST FOR CONTINUATION OF BOTH WIND AND HEAVY SURF
ADVISORIES FOR WEST OF CAPE ESPENBERG.

ALOFT...CLOSED 500 MB LOW IN THE LOW 4900S DAM NORTH OF POINT
BARROW TROUGHING SOUTHWARD TO PRINCE WILLIAM SOUND. 500 MB RIDGE
PENETRATES NORTHWARD ACROSS THE WESTERN BERING SEA. PATTERN
PRODUCES SPEEDY NORTH FLOW ALOFT GENERALLY WEST OF AN ICY CAPE TO
KENAI PENINSULA LINE. EMBEDDED SHORTWAVE FROM WAINWRIGHT SOUTH TO
BRISTOL BAY MAINTAINING CLOUD COVER...SURFACE TROUGHING...AND
FLURRIES AND SNOW SHOWERS. AT 850 MB...STRONG WARM ADVECTION IN
WESTERLY FLOW WILL SIGNAL PROGRESSIVE PATTERN CHANGE STATEWIDE
THROUGH THE HEART OF THE WORK WEEK. COLDEST 850 MB TEMPERATURES
ARE NOW CENTERED OVER EAGLE...POISED TO LEAP THE BORDER INTO
YUKON TERRITORY.

MODELS...AGREEING ROUGHLY ON FEATURE PLACEMENT THROUGH
WEDNESDAY...BUT SOME MAJOR DIFFERENCES ON TIMING OF NORTH PACIFIC
SYSTEM ARRIVING IN THE WESTERN BERING BY MIDWEEK. BOTH AVN AND
ETA SHOW DRAMATIC DEEPENING INTO THE 970S MB WITH THIS
SYSTEM...BUT ETA BOMBS ON WEDNESDAY MORNING NORTH OF AMCHITKA
WHILE AVN BOMBS NEAR SAINT LAWRENCE ISLAND WEDNESDAY NIGHT. KEY
SIMILARITY IS THAT BOTH SOLUTIONS MAINTAIN THEIR DEPTH AND MOVE
THIS DEEP SYSTEM NORTH FOR THE REMAINDER OF THE WORK WEEK. SYSTEM
HAS EXCELLENT CLASSICAL WESTWARD-TILT DYNAMICS...WITH CLOSED LOW
OVER KAMCHATKA AND FLAT-TOPPED RIDGE TRANSLATING EASTWARD AND
PUSHING NORTHWARD OVER THE WESTERN INTERIOR. WILL LEAN TO AVN FOR
GENERAL TIMING OF WEST COAST AND NORTH SLOPE ACTION...ALTHOUGH
RUN TO RUN CONTINUITY HAS NOT BEEN IMPRESSIVE...AND KEEP AN
AVN/ETA BLEND GOING FOR THE EASTERN INTERIOR.

NORTH SLOPE...WAINWRIGHT LOW WILL REMAIN IN PLACE THROUGH MIDWEEK
TO SUPPORT COASTAL SNOW SHOWERS AND SOUTHWESTERLY FLOW WEST OF
POINT BARROW. TIGHTENING GRADIENT BETWEEN LOW AND TRANSLATING
HIGH OVER EASTERN INTERIOR WILL PRODUCE SOME SPEEDY GAP FLOW
THROUGH THE BROOKS RANGE PASSES ON TUESDAY...AND WARMING TREND
CONTINUING THROUGH WEDNESDAY. ARCTIC MARINERS...GENERAL OFFSHORE
FLOW THROUGH TUESDAY...WITH WINDS APPROACHING BRISK NEAR CAPE
LISBURNE.

WEST COAST...BRACING FOR THE BIG BLOW AT THE END OF THE WORK
WEEK. KAMCHATKA LOW WILL TRANSLATE EASTWARD TO BERING STRAIT
TUESDAY... PUSHING SNOW TO A SEWARD PENINSULA TO BRISTOL BAY LINE
MONDAY NIGHT...AND THEN OVER ALL OF THE WEST COAST BY TUESDAY.
WINDS WILL BE BREEZY WITH BLOWING/DRIFTING SNOW LIKELY...AND
POSSIBILITY OF A RAIN/SNOW MIX GENERALLY FROM THE YUKON DELTA
SOUTHWARD. WILL HOLD SYSTEM TO ADVISORY CRITERIA...AS PROGRESSIVE
PATTERN WILL MAKE IT DIFFICULT TO MEET BLIZZARD CRITERIA. THINGS
WILL CALM DOWN WEDNESDAY IN ADVANCE OF THE MAIN EVENT STARTING
EARLY THURSDAY MORNING. MARINERS...SIGNALMAN GETTING EXERCISE
WITH GALES IN AREA 14 SPREADING INTO AREA 9 TUESDAY MORNING...AND
SMALL CRAFT PENNANTS HOISTED FOR AREA 10. WILL MAINTAIN FREEZING
SPRAY LANGUAGE FROM SAINT LAWRENCE ISLAND NORTHWARD. HAVE ISSUED
MARINE WEATHER STATEMENT FOR AREAS 9...10B...AND 14 AS AN OUTLOOK
FOR POSSIBLE COASTAL FLOOD PROBLEMS NEAR NOME AND SHISHMAREF AT
THE END OF THE WORK WEEK. THANKS OME OTZ AND ANC FOR YOUR
EXCELLENT FORECAST INPUT TODAY...AND THANKS IN ADVANCE FOR YOUR
HELP TOMORROW.

INTERIOR...CLEAR SKIES AND COOLISH TEMPERATURES HEADING EAST INTO
CANADA AS NEXT SYSTEM FROM THE WEST PUSHES SNOW TO A
KOTZEBUE-MCGRATH LINE BY TUESDAY MORNING...AND THEN AN
AMBLER-DENALI LINE BY TUESDAY NIGHT. SOUTHWEST FLOW WILL IMPROVE
SNOW CHANCES FOR THE WESTERN ALASKA RANGE...THE TANANA
VALLEY...AND UP TO THE DALTON HIGHWAY SOUTH OF THE BROOKS RANGE.
TEMPERATURES WILL MODERATE TO NEAR ZERO AS THE SYSTEM MAKES ITS
ADVANCE.

MEDIUM RANGE...GENERALLY PLACING 500 MB FAST FLOW OVER SOUTHERN
BERING SEA...WITH SOME HINT OF RIDGING REMAINING FROM BRISTOL BAY
 NORTHWARD UP THE WEST COAST. CLOSED LOW ALOFT IN THE 4800S DAM
WILL ABSORB MOST ENERGY FROM SYSTEM MOVING UP THE WEST COAST
AFTER SWINGING POWERFUL SHORTWAVE ACROSS NORTHERN INTERIOR.
SURFACE SYSTEM WILL RETAIN ITS MOXIE...ECMWF PARKS IT OVER THE
SEWARD PENINSULA WHILE UKMET AND DOMESTIC COLLEAGUES PUSH THE
SYSTEM TO PRUDHOE BAY BY THE WEEKEND. WILL OPT FOR A DIFFERENCE
SPLIT HERE UNTIL THE TRACK OF THE STORM BECOMES BETTER DESCRIBED.
PATTERN WILL PRODUCE STRONG NORTH WINDS DOWN THE WEST
COAST...ENHANCED WEEKEND SNOW CHANCES IN THE TANANA AND YUKON
VALLEYS...AND USUAL ROUNDS OF CLOUDS AND FOG FOR THE BEAUFORT SEA
COASTS.

.AFG...WATCH/WARNING/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING: AREAS 9A/9B/14
         HEAVY FREEZING SPRAY WARNING: AREAS 10B/11A
         SMALL CRAFT ADVISORY: AREAS 10A/10B

TS NOV 03