586
AGAK78 PACR 251929
HMDACR
HYDROMETEOROLOGICAL DISCUSSION
NWS ALASKA PACIFIC RIVER FORECAST CENTER ANCHORAGE AK
800 AM AKDT TUE NOV 24 2009
..FLOOD POTENTIAL
THE FLOOD POTENTIAL IS CURRENTLY LOW STATEWIDE.
..HYDROMETEOROLOGICAL CONDITIONS
PRECIPITATION AMOUNTS OVER THE LAST 7 DAYS WERE WAY DOWN BY OVER
HALF FROM THE PREVIOUS WEEK. VALUES RANGING BETWEEN 2 AND 3.5
INCHES WERE RECORDED AT THE FAVORED LOCATIONS WITH A LOW IN THE
GULF EARLY IN THE PERIOD NAMELY PORTAGE... WHITTIER AND THE
SOUTHERN SOUTHEAST. OTHERWISE UNDER THE EFFECTS OF A RIDGE IN THE
BERING COLD NORTHWEST FLOW ALOFT KEPT THE INTERIOR AND WEST DRY AND
BELOW NORMAL IN TEMPERATURES AND PRECIPITATION. A PATTERN CHANGE
BEGAN ON FRIDAY OF LAST WEEK WHEN A LARGE STORM ENTERED THE WESTERN
BERING THEN PROCEEDED TO TAKE OVER THE BERING SEA BY SATURDAY. THE
MORE ACTIVE WEATHER PATTERN IN THE BERING USHERED IN A RETURN TO
MUCH MORE SEASONAL TEMPERATURES AND PRECIPITATION ACROSS THE
SOUTHERN MAINLAND.
WITH A LOW IN THE BERING A WAVE TRAIN HAS DEVELOPED THAT ALLOWS
STORM SYSTEMS TO CLIMB THE ALEUTIAN CHAIN AND CROSS INTO THE GULF.
THE FIRST OF THESE SYSTEMS IS POISED TO REACH THE SOUTHEAST ON
WEDNESDAY AND THEN ANOTHER ON FRIDAY. SNOW ON THE BACK SIDE OF
THESE LOWS WILL BE LIKELY COVER THE SOUTHCENTRAL MOUNTAINS AS RAIN
AND SNOW MIX AT LOWER ELEVATIONS. MODELS ARE PREDICTING BETWEEN AND
2 AND 3.5 INCHES OF PRECIPITATION FROM PRINCE WILLIAM SOUND TO THE
SOUTHERN PANHANDLE AND WILL MOST LIKELY BE IN THE FORM OF RAIN.
MORE FAVORED WINDWARD AREAS COULD SEE DOUBLE THOSE AMOUNTS.
ICE HAS QUICKLY FORMED OVER MANY RIVERS AND LAKES ACROSS MAINLAND
ALASKA WITH THE RECENT COLD SNAP. SEVERAL INCHES OF ICE ARE BEING
REPORTED BY ICE OBSERVES IN THE INTERIOR AND COPPER RIVER BASIN.
SNOWFALL AMOUNTS HAVE INCREASED SUBSTANTIALLY OVER THE SOUTHCENTRAL
REGIONS DURING THE LAST WEEK WITH A FOOT OR TWO BEING RECORDED IN
THE KENAI AND CHUGACH MOUNTAINS.
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THE HYDROMET DISCUSSION WILL BE ISSUED EVERY TUESDAY FROM NOVEMBER
THROUGH APRIL. A GRAPHICAL VERSION OF THE HYDROMET DISCUSSION IS
AVAILABLE AT HTTP://APRFC.ARH.NOAA.GOV/PRODUCTS/GHMD.PHP
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