High Wind in Alaska, March 21, 2003

NORTH ALASKA FORECAST DISCUSSION
400 AM AST FRI MAR 21 2003

AT THE SURFACE... A 1028 MB HIGH IS PARKED 200 NM NORTH OF POINT
BARROW CONTROLLING THE ARCTIC...WITH A 1025 MB HIGH OVER THE WESTERN
BERING SEA. A STRING OF FILLING SURFACE LOWS EXTENDS FROM BRISTOL
BAY TO EAGLE...ALL AT ROUGHLY 1002 MB...AND PUSHING REMNANT
OCCLUSIONS NORTHWARD. NET EFFECT HAS BEEN TO CLOUD UP THE SKIES AS
THESE PUSH THROUGH WITH NO PRECIPITATION.

ALOFT...LONGWAVE 500 MB TROUGH PATTERN CONTINUES...WITH CLOSED LOW
OVER WRANGEL ISLAND AND TROUGH EXTENDING SOUTHEASTWARD TO CLOSED LOW
OVER LAKE ILIAMNA. A WEAK RIDGE POKES NORTHWESTWARD FROM SKAGWAY TO
BETTLES...WHILE A MORE SUBSTANTIAL RIDGE HANGS OUT OVER THE WESTERN
BERING SEA FROM DUTCH HARBOR NORTHWARD TO ANADYR. PATTERN LEAVES
WESTERN HALF OF STATE IN LOW FLOW ALOFT...WHILE A GENTLE SOUTHERLY
FLOW ALOFT DOMINATES THE EASTERN HALF OF THE STATE. NO DYNAMICS
HOMEWORK TONIGHT...AS AIR MASS ALOFT REMAINS VERY DRY WITH EXCEPTION
OF SOME MOISTURE INCURSION INTO THE MIDDLE/LOWER YUKON VALLEYS TO
PRODUCE SOME ISOLATED SNOW SHOWERS WHERE HELPED BY OROGRAPHY...LIKE
KALTAG. AT 850 MB...MODEST COLD ADVECTION CONTINUES DOWN THE WEST
COAST...AND AS THE WINDS MIX DOWN THE SURFACE...BORDERLINE ADVISORY
LEVEL WIND CHILLS RESULT.

MODELS...PRODUCING SIMILAR SOLUTIONS THROUGH SUNDAY MORNING...AS ETA
HAS CAUGHT UP TO AVN SOLUTION FOR TRANSLATION OF WRANGEL ISLAND
CLOSED LOW EASTWARD TO POINT BARROW BY THE WEEKEND...AND THE THERMAL
FIELDS ARE MATCHING UP BETTER THAN PREVIOUS RUNS. MODELS MOVE LAKE
ILIAMNA CLOSED LOW ALOFT TO THE KENAI PENINSULA FRIDAY
AFTERNOON...AND INTO THE NORTHEASTERN GULF OF ALASKA BY SUNDAY
MORNING. THIS GENERAL TRANSLATION OF THE LONGWAVE TROUGH PATTERN
EASTWARD WILL ALLOW WESTERN BERING RIDGE TO REMAIN -- AND RELAX --
IN PLACE...AND EASE THE COMPANION RIDGE TO THE EAST ACROSS THE
CANADIAN BORDER.

NORTH SLOPE...CLOSED LOW APPROACHING FROM WRANGEL ISLAND WILL
SUPPORT A SMEARING OF SOME PERIODS OF LIGHT SNOW ALONG THE ARCTIC
COAST FRIDAY NIGHT...AND THROUGH BARROW ON SATURDAY...BEFORE THE
FEATURE LIFTS NORTHEASTWARD. NOT MUCH TEMPERATURE ADVECTION AND
LIGHT WINDS WILL PRODUCE LITTLE CHANGE TO TEMPERATURES AND KEEP
AREAS OF FOG IN THE FORECAST THROUGH SATURDAY NIGHT. ARCTIC
MARINERS...FLAG LOCKER REMAINS PADLOCKED WITH GENERAL EASTERLY WINDS
SHIFTING TO THE WEST AS THE SHORTWAVE AND SURFACE TROUGH SWING
THROUGH.

WEST COAST...WESTERN BERING SURFACE HIGH PRESSURE OOZING EASTWARD
WILL SLACKEN THE SURFACE PRESSURE GRADIENT AND REDUCE WIND SPEEDS
DURING THE DAY FRIDAY...WITH FURTHER REDUCTIONS ON SATURDAY. HIGH
PRESSURE WILL KEEP SKIES PRETTY CLEAR...AND SOME GENTLE WARMING WITH
DIURNAL HEATING. WEST COAST MARINERS...WILL HAUL DOWN FLAGS WITH THE
MORNING PACKAGE AS WIND SPEEDS MODERATE BELOW ADVISORY LEVELS...BUT
WILL KEEP HEAVY FREEZING SPRAY WARNINGS IN PLACE FOR AREA 14.

INTERIOR...WEAK SURFACE TROUGH UNDER LONGWAVE SPONSOR ALOFT WILL
TRANSLATE EASTWARD FROM LOWER YUKON VALLEY TO A DENALI-CHANDALAR
LINE BY SATURDAY NIGHT. COMBINED WITH CIRCULATION ABOUT EASTERN GULF
OF ALASKA LOW...WILL PRODUCE A FEW FLURRIES AND A ROUND OF CLOUDS AS
IT PUSHES THROUGH. TEMPERATURES WILL MODERATE SLIGHTLY WITH LOWER
HEIGHTS ALOFT...BUT THIS SHOULD ONLY KNOCK OFF A FEW DEGREES.

MEDIUM RANGE...AGREEING ON A VERY BASIC STORY BUT DIFFERING WIDELY
ON HOW IT IS TOLD. ALL MAINTAIN TROUGH OVER WESTERN HALF OF ALASKA
WITH RIDGES OVER THE BERING SEA AND POKING INTO THE EASTERN HALF OF
THE STATE FROM SOUTHERN YUKON TERRITORY. MRF/AVN TURN BERING SEA
RIDGE INTO FULL-BLOWN OMEGA BLOCK WHILE ECMWF/UKMET SOLUTIONS
SOMEWHAT MORE PROGRESSIVE. FOR THE FIRST PART OF THE WORK
WEEK...WEST COAST WILL BE RELATIVELY CLEAR...WESTERN INTERIOR WILL
SEE A FEW CLOUDS...AND EASTERN INTERIOR WILL BE WARMER WITH A FEW
CLOUDS AND SOUTHERLY FLOW. NORTH SLOPE WILL RECEIVE USUAL ROUNDS OF
SHORTWAVE SCRAPES. NO SERIOUS PRECIPITATION ON THE MAP THROUGH
MIDWEEK.

.AFG...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY: AREA 14

TS MAR 03