Small Craft Advisory 942, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
434 PM AKST THU NOV 26 2015

.ANALYSIS AND UPPER LEVELS...
A HIGHLY AMPLIFIED UPPER LEVEL WEATHER PATTERN CONTINUES OVER
THE REGION WITH THE SOUTHERN MAINLAND ENTIRELY WITHIN THE DEEP
SOUTHERLY FLOW BETWEEN A STRONG HIGH PRESSURE RIDGE OVER WESTERN
CANADA AND A DEEP TROUGH OVER THE BERING SEA.

WITHIN THIS PATTERN...A WELL-DEFINED UPPER LEVEL SHORTWAVE TROUGH
CONTINUES TO MOVE INLAND ACROSS THE COPPER RIVER BASIN ON ITS WAY
TOWARD THE YUKON. THIS IS THE SYSTEM THAT BROUGHT UP TO ONE-HALF
INCH OF RAIN TO THE ANCHORAGE AREA OVERNIGHT. DRY AIR WRAPPING
INTO THE BACK OF THIS SYSTEM HAS RESULTED IN SUBSIDENCE ALOFT OVER
THE BRISTOL BAY...KENAI PENINSULA...AND ANCHORAGE AREAS...RESULTING
IN AREAS OF FOG. AN EQUALLY SHARP SHORTWAVE RIDGE THAT EXTENDS
FROM THE LONGWAVE RIDGE OVER WESTERN CANADA EXTENDS ACROSS THE
WESTERN GULF AND OVER SOUTHWEST ALASKA AND THE NORTHERN
BERING...ALSO MOVING NORTH AND INLAND. ANOTHER STRONG SHORTWAVE
TROUGH IS LOCATED IN THE NORTH PACIFIC AND WILL MOVE NORTH TOWARD
SOUTHERN ALASKA THROUGH TONIGHT BEFORE MOVING INLAND FRIDAY.
FURTHER WEST...THE STRONGEST SYSTEM ON THE WEATHER MAP IS A
STACKED LOW PRESSURE SYSTEM WITH A 970 MB SURFACE LOW JUST SOUTH
OF THE EASTERN ALEUTIANS. THIS SYSTEMS CIRCULATION ENCOMPASSES
MOST OF THE BERING REGION...BUT IS CURRENTLY WEAKENING...WITH
STORM FORCE WINDS LARGELY DIMINISHING TO STRONG GALES OVER OUR
AREA OF RESPONSIBILITY.

&&

.MODEL DISCUSSION...
THE MODELS REMAIN IN GREAT SYNOPTIC AGREEMENT UNTIL SATURDAY
AFTERNOON WHEN DISCREPANCIES BEGIN TO EMERGE WITH THE TIMING AND
INTENSITY OF THE NEXT LOW MOVING INTO THE WESTERN ALEUTIANS. THE
SHORTWAVE OVER THE COPPER RIVER BASIN WILL CONTINUE TO MOVE OUT OF
THE EASTERN MAINLAND OF ALASKA INTO CANADA. THE NEXT SYSTEM MOVES
QUICKLY NORTH INTO THE GULF THIS EVENING AND MOVES INTO SOUTHWEST
ALASKA TONIGHT AND THEN INTO THE NORTHERN BERING BEFORE STALLING
OUT BETWEEN SAINT MATTHEW AND NUNIVAK ISLANDS LATE FRIDAY NIGHT.
THE SUBSEQUENT SYSTEM MOVES NORTH IMMEDIATELY BEHIND THIS
DISTURBANCE INTO THE GULF EARLY TOMORROW (FRIDAY MORNING) AND WILL
MOVE ALMOST DUE NORTH TOWARD THE INTERIOR. THIS SYSTEM WILL HELP
REINFORCE THE EXISTING BARRIER JET ALONG THE COAST BEFORE IT MOVES
INLAND LATE TONIGHT INTO FRIDAY MORNING.

MEANWHILE...THE LOW JUST SOUTH OF THE EASTERN ALEUTIANS CONTINUES
TO WEAKEN BEFORE CURVING NORTHEAST TOWARD THE AKPEN AND KODIAK AND
THEN BECOMING ABSORBED INTO THE NEXT LOW MOVING ACROSS THE
ALEUTIANS THIS WEEKEND. THIS NEXT LOW WILL BRING A LARGE AREA OF
GALES TO THE ALEUTIAN REGION WITH SOME LOCALIZED STORM FORCE WINDS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
YET ANOTHER DISTURBANCE COMES IN FROM THE GULF TONIGHT SPREADING
RAIN FROM EAST TO WEST ACROSS MOST OF THE GULF COAST. THE COOK
INLET REGION WILL REMAIN LARGELY DOWNSLOPED AND DRY WITH THIS
DISTURBANCE...HOWEVER SOME SPRINKLES OR LIGHT RAIN COULD MAKE IT
TO THE SURFACE...NOTHING MAJOR. A BRIEF PERIOD OF FOGGY CONDITIONS
AROUND THE ANCHORAGE AREA WILL LINGER THROUGH EARLY EVENING BEFORE
NORTHWESTERLY WINDS PICK UP AND MIX THE LOW ATMOSPHERE A BIT.
ANOTHER TROUGH SWINGS FROM SOUTH TO NORTH TOMORROW...KEEPING RAIN
GOING ALONG THE NORTH GULF COAST...AND ALSO USHERS IN A NEW AIR
MASS IN THE LATE AFTERNOON ON FRIDAY. THIS AIR MASS IS AN UNSTABLE
ONE AND WILL LEAD TO WIDESPREAD SHOWER ACTIVITY IN MOST AREAS
AROUND THE SOUTHCENTRAL. TEMPERATURES IN THE LOW LEVELS WILL
GENERALLY BE WARM ENOUGH FOR RAIN...HOWEVER IN THESE PATTERNS
HEAVIER BOUTS OF PRECIPITATION WILL LEAD TO PERIODIC CHANGEOVER TO
SNOW AS COLD AIR GETS DRAGGED DOWN.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONT OVER THE ALASKA PENINSULA MOVES NORTH TONIGHT SPREADING
PRECIPITATION ACROSS THE SOUTHWEST. PRECIPITATION WILL CONTINUE AS
SNOW AND RAIN ACROSS THE ALASKA PENINSULA WITH SNOW DEVELOPING ACROSS
MUCH OF THE SOUTHWEST MAINLAND. THE HIGHEST ACCUMULATIONS WILL BE
NORTH AND WEST OF DILLINGHAM WITH UPSLOPE FLOW ACROSS EAST FACING
MOUNTAINS. AS THE FRONT MOVES NORTH TONIGHT STRONG EASTERLY FLOW
INCREASES AND CONTINUES INTO FRIDAY. THIS FLOW BRINGS IN A
SLIGHTLY WARMER PACIFIC AIR MASS JUST OFF THE SURFACE. THERE WILL
BE A CHANCE FOR LIGHT FREEZING RAIN ACROSS THE SOUTHWEST ALONG
THE FRONTAL PASSAGE...HOWEVER LITTLE ACCUMULATION IS EXPECTED AS
THE FRONT WEAKENS RAPIDLY ON ITS NORTHWARD TRACK. SCATTERED RAIN
AND SNOW SHOWERS CONTINUE THROUGH SATURDAY AS ANOTHER SURFACE LOW
DEVELOPS LATE FRIDAY ALONG THE ALASKA PENINSULA AND THEN LIFTS
SLOWLY NORTH.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE SURFACE LOW ALONG THE CENTRAL ALEUTIANS MOVES TO THE ALASKA
PENINSULA TONIGHT BRINGING RAIN...SNOW AND GUSTY WINDS THROUGH
FRIDAY. GALE WINDS ACROSS THE MARINE AREAS ALONG THE WESTERN
BERING AND ALEUTIANS WILL TAPER OFF FRIDAY AFTERNOON...HOWEVER THE
NEXT STORM SYSTEM MOVES INTO THE WESTERN ALEUTIANS EARLY SATURDAY.
GUSTY WINDS ACROSS THE EASTERN BERING AND ALEUTIANS CONTINUE INTO
EARLY SATURDAY AND THEN THE SURFACE LOW WEAKENS AS IT MOVES INTO
THE NORTHERN BERING.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
STARTING OFF THE LONG TERM FORECAST PERIOD...THE MODELS ARE IN
EXCELLENT AGREEMENT ON THE OVERALL PATTERN GIVEN BEING 3 DAYS OUT.
THE PATTERN FEATURES A VERY BROAD UPPER LEVEL TROUGH ANCHORED OVER
THE BERING SEA. MEANWHILE LOBES OF UPPER-LEVEL ENERGY REVOLVING
CYCLONICALLY AROUND THE CENTER OF THE TROUGH OVER THE WESTERN
BERING WILL CONTINUE TO TRACK INTO THE NORTHEAST PACIFIC AND GULF
OF ALASKA. A HIGHLY ENERGETIC SUBTROPICAL JET SOUTH OF THE WESTERN
ALEUTIANS WILL MOVE EAST THROUGH THE FLOW AS AN UPPER LEVEL
SHORTWAVE TROUGH...WHICH IS ALSO ONE OF THE AFOREMENTIONED LOBES
OF ENERGY...PUSHES INTO THE WESTERN GULF SATURDAY NIGHT.

WITH TIME THE MODELS PREDICTABLY BEGIN DIFFERING MORE AND MORE ON
WHERE THE INDIVIDUAL UPPER-LEVEL FEATURES ARE...WHICH IN TURN
IMPACTS WHERE EACH MODEL DEPICTS SURFACE LOW PRESSURE DEVELOPMENT.
HOWEVER...THE BROAD PATTERN INDICATES A GRADUAL SOUTHWARD DRIFT OF
THE SUBTROPICAL JET FURTHER FROM THE ALEUTIANS...WITH GRADUAL
EASTWARD MOVEMENT OF THE UPPER-LEVEL COLD AIR TOWARD MAINLAND
ALASKA.

THE RESULT OF THIS PATTERN FAVORS AN EVENTUAL RETURN TO MORE
SEASONABLE TEMPERATURES FOR MUCH OF SOUTHERN ALASKA...THOUGH IT
SHOULD BE NOTED THAT THE PATTERN ALSO DOES NOT FAVOR INTRUSIONS OF
BITTERLY COLD AIR INTO SOUTHERN ALASKA. WITH THE CENTER OF THE
UPPER-LEVEL TROUGH EXPECTED TO REMAIN WEST OF SOUTHCENTRAL AND
GENERAL RIDGING EAST OF THE AREA...THAT PATTERN ALSO TENDS TO
FAVOR ACTIVE WEATHER WITH RELATIVELY FREQUENT ROUNDS OF
PRECIPITATION.

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM WARNING 119.
         GALE WARNING 120 125 128 129 130 131 132 139 155 170 171
                      172 173 174 175 176 177 178 179 181 185.
         HEAVY FREEZING SPRAY WARNING...181 185.

&&

SYNOPSIS AND MODEL DISCUSSION...CC
SOUTHCENTRAL ALASKA...MTL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...JW

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>