Dense Fog Advisory 21, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKDT WED OCT 28 2009

.MODEL DISCUSSION...
THE MODELS HAVE COME BACK INTO BETTER AGREEMENT IN THE GULF, BUT IT
APPEARS TO HAVE LOST CONSENSUS OVER THE BERING SEA. OVER THE BERING,
THE GFS AND UKMET MODEL SWINGS THE LOW, SOUTHWEST OF ATTU, NORTHWARD
TOWARD SIBERIA WHILE THE EUROPEAN AND THE NAM MOVES IT A LITTLE
FARTHER EAST BEFORE TURNING IT NORTH ON FRIDAY. CURRENTLY, WE ARE
LEANING TOWARD THE NAM SOLUTION OVER THE BERING. GFS CONTINUES TO BE
THE MOST CONSISTENT MODEL IN THE GULF AND MAINLAND ALASKA.

.ANALYSIS AND UPPER LEVELS...
UPPER LEVELS...THE UPPER LOW NEAR KODIAK ISLAND CONTINUES TO MOVE
EAST IN THE GULF. THE STRONG UPPER RIDGE REMAINS OVER THE EASTERN
BERING.
AT THE SURFACE...THE HIGH OVER THE EASTERN BERING CONTINUES TO SHIFT
TOWARD NORTHERN ALASKA. A STORM JUST SOUTH OF THE GULF CONTINUES TO
MOVE NORTHEAST TOWARD THE PANHANDLE. THE PRESSURE GRADIENT CONTINUES
TO INCREASE OVER THE SOUTHERN MAINLAND AND THE GULF. THE LOW
SOUTHWEST OF ATTU CONTINUES TO MOVE NORTHEAST.

.SHORT TERM FORECAST...
UPPER AIR...THE LOW NEAR KODIAK WILL BECOME NEARLY STATIONARY OVER
THE NORTHERN GULF THURSDAY. THE STATIONARY RIDGE OVER THE EASTERN
BERING WILL CONTINUE TO FORM A BLOCK TO THE STORM SYSTEM OVER THE
WESTERN BERING.

SOUTHCENTRAL AND THE GULF...A HIGH WILL DEVELOP OVER NORTHERN ALASKA
TONIGHT WITH A RIDGE EXTENDING INTO THE EASTERN BERING THROUGH
FRIDAY. A TROUGH WILL FORM OVER THE NORTHERN GULF THURSDAY. THE
STRENGTHENING PRESSURE GRADIENT BETWEEN THESE TWO FEATURES WILL
PRODUCE GUSTY WINDS THROUGH CHANNELED TERRAIN ALONG THE ALASKA AND
ALEUTIAN RANGES AND THE CHUGACH MOUNTAINS THROUGH FRIDAY. RAIN AND
SNOW SHOWERS OVER PRINCE WILLIAM SOUND, KENAI PENINSULA WILL END THIS
EVENING. SKIES WILL CLEAR FROM THE FROM THE NORTH TONIGHT.

SOUTHWEST ALASKA...SKIES WILL GRADUALLY CLEAR FROM THE NORTH AND WEST
TONIGHT AND THURSDAY MORNING. GUSTY NORTH WINDS WILL REMAIN OVER THE
INTERIOR SECTIONS THROUGH FRIDAY.

BERING SEA AND ALEUTIANS...THE 967 MB STORM SOUTHWEST OF ATTU WILL
MOVE EAST-NORTHEAST AND WEAKEN TO 1003 MB OVER THE SOUTH-CENTRAL
BERING FRIDAY AFTERNOON. THE WEATHER FRONT ACROSS THE WESTERN BERING
SEA WILL DISSIPATE OVER THE CENTRAL BERING AND CENTRAL ALEUTIANS
THURSDAY. GALE FORCE WINDS OVER THE WESTERN BERING WILL DIMINISH
THURSDAY NIGHT. RAIN ALONG THE FRONT WILL BECOME SHOWERS THURSDAY.

.LONG TERM FORECAST...
THE LONG RANGE MODEL ARE IN REASONABLE AGREEMENT THROUGH THE WEEKEND.
THE UPPER LOW REMAINS OVER THE GULF WHILE THE UPPER RIDGE OVER THE
EASTERN BERING SLOWLY WEAKENS AND DRIFTS INTO THE WEST COAST OF
ALASKA BY SUNDAY. THE PRESSURE GRADIENT ACROSS THE SOUTHERN MAINLAND
WILL EASE A BIT OVER THE WEEKEND. A WEAK LOW WILL EVENTUALLY DEVELOP
FROM THE TROUGH OVER THE NORTHERN GULF AND WILL PRODUCE SCATTERED
SHOWERS ALONG THE GULF COAST. SOUTHWEST ALASKA AND THE SOUTHCENTRAL
INTERIOR WILL REMAIN MOSTLY CLEAR THROUGH THE WEEKEND. ANOTHER
WEATHER FRONT FORMING EAST OF THE KAMCHATKA PENINSULA FRIDAY NIGHT
WILL SWING NORTH AND EAST AND DISSIPATE OVER THE NORTHERN AND EASTERN
BERING SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORM 176
         GALE 172 175 185
FIRE WEATHER...NONE

NM OCT 09