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FXUS21 KWNC 241950
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 24 2014

SYNOPSIS: LOW PRESSURE SYSTEMS ARE PREDICTED TO BRING UNSETTLED WEATHER TO NEW
ENGLAND AND THE PACIFIC NORTHWEST, WHILE THE REST OF THE LOWER 48 IS EXPECTED
TO SEE RELATIVELY CALM WEATHER.  NO COLD AIR OUTBREAKS ARE EXPECTED, AS THE
FLOW IS PREDICTED TO COME PRIMARILY OFF THE PACIFIC OCEAN.

HAZARDS

HEAVY RAIN ALONG THE WEST COAST FROM NORTHERN CALIFORNIA TO THE CANADIAN
BORDER, MON-WED, OCT 27-29.

HIGH WINDS ACROSS THE UPPER MIDWEST AND GREAT LAKES, TUE, OCT 28.

HIGH WINDS ACROSS NEW ENGLAND, MON, OCT 27.

HIGH WINDS AND SIGNIFICANT WAVES FOR THE WESTERN ALASKAN COAST, MON, OCT 27 AND
AGAIN THU, OCT 30.

HIGH WINDS AND SIGNIFICANT WAVES FOR THE SOUTHWESTERN ALASKAN COAST, WED-THU,
OCT 29-30.

HIGH WINDS FOR THE SOUTHERN ALASKAN COAST AND PANHANDLE, THU, OCT 30.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, SOUTHEAST,
PACIFIC NORTHWEST, GREAT BASIN, AND CALIFORNIA.

DETAILED SUMMARY

FOR MONDAY OCTOBER 27 - FRIDAY OCTOBER 31: A STRONG UPPER-LEVEL TROUGH IS
FORECAST TO MOVE THROUGH SOUTHERN CANADA AND AMPLIFY AS IT MOVES PAST THE GREAT
LAKES AND THE NORTHEAST.  ITS ASSOCIATED SURFACE LOW IS THEN EXPECTED TO
STRENGTHEN AND INCREASE THE PRESSURE GRADIENT AROUND IT.  HIGH WINDS ARE
EXPECTED IN NEW ENGLAND ON THE 27TH DUE TO THIS STRONG PRESSURE GRADIENT.



CONCURRENTLY, AN UPPER-LEVEL TROUGH IS FORECAST TO MAKE ITS WAY ACROSS THE
LOWER 48.  WARM, MOIST FLOW FROM THE GULF OF MEXICO IS EXPECTED AHEAD OF THE
SURFACE COLD FRONT, LEADING TO SHOWERS AND LOCALLY SEVERE WEATHER.  THE LOW IS
CURRENTLY PREDICTED TO INTENSIFY AS IT NEARS THE GREAT LAKES, WHICH MEANS THE
GREATEST CHANCE FOR HEAVY RAIN AND WIDESPREAD SEVERE WEATHER EXISTS FROM THE
OHIO VALLEY SOUTHWARD TO THE LOWER MISSISSIPPI VALLEY ON EITHER TUESDAY THE
28TH OR WEDNESDAY THE 29TH.  ALSO, ON THE BACKSIDE OF THE STORM, ENOUGH COLD
AIR MIGHT EXIST FOR SOME SNOW IN PARTS OF THE DAKOTAS AND UPPER MIDWEST.  AT
THIS TIME, ANY POTENTIAL SNOWFALL DOES NOT APPEAR TO REACH HAZARDOUS CRITERIA,
BUT IS MENTIONED AS IT WOULD BE THE FIRST APPRECIABLE SNOWFALL THIS SEASON FOR
THIS PART OF THE COUNTRY.  HOWEVER, STRONG WINDS ARE ANTICIPATED IN PARTS OF
THE UPPER MIDWEST AND WESTERN GREAT LAKES ON THE 28TH DUE TO A STRENGTHENING
PRESSURE GRADIENT.



THE REMNANTS OF TROPICAL STORM ANA IS THEN EXPECTED TO INTERACT WITH AN
EXTRATROPICAL UPPER-LEVEL TROUGH AND MOVE INTO THE PACIFIC NORTHWEST.  WHILE
THE EXACT DETAILS OF THIS INTERACTION REMAIN UNCERTAIN, THERE IS HIGH
CONFIDENCE THAT ANA`S REMNANTS WILL BRING HEAVY RAIN ALONG THE WEST COAST, FROM
NORTHERN CALIFORNIA TO THE CANADIAN BORDER FROM THE 27TH TO THE 29TH.  AN
ADDITIONAL 3 TO 5 INCHES OF RAIN IS POSSIBLE DURING THIS TIME PERIOD.
CONSIDERING THE ALMOST 10 INCHES THAT WILL HAVE FALLEN DURING THE PAST SEVEN
DAYS AS WELL AS BEFORE THIS OUTLOOK PERIOD BEGINS, FLOODING IS A DISTINCT
POSSIBILITY.



AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE FROM NORTHEASTERN RUSSIA ACROSS THE
BERING SEA.  THE ASSOCIATED SURFACE LOW IS EXPECTED TO DIRECT HIGH WINDS AND
SIGNIFICANT WAVES TO THE WEST COAST OF ALASKA, FROM ABOUT THE KUSKOKWIM DELTA
TO KOTZEBUE SOUND ON THE 27TH.  CONCURRENTLY, A VERY STRONG STORM IS FORECAST
TO FORM AND MOVE FROM JUST NORTH OF JAPAN INTO THE BERING SEA.  THIS STORM IS
PREDICTED TO BRING ANOTHER ROUND OF HIGH WINDS AND SIGNIFIGANT WAVES TO MOST OF
THE SOUTHWEST COAST OF ALASKA ON THE 29TH AND SPREADING TO MOST OF THE WEST
COAST OF THE MAINLAND, NORTHERN GULF OF ALASKA COASTLINE, AND THE PANHANDLE.



FOR SATURDAY NOVEMBER 01 - FRIDAY NOVEMBER 07: THERE IS A LOT OF DISAGREEMENT
AT THIS TIME RANGE BETWEEN THE OPERATIONAL RUNS OF THE ECMWF AND GFS MODELS.
THE ECMWF PREDICTS A STRONG UPPER-LEVEL TROUGH DIGGING DOWN INTO THE
MISSISSIPPI VALLEY WITH A STRONG COASTAL LOW DEVELOPING OFF THE MID-ATLANTIC
COAST.  THIS SOLUTION WOULD BRING HEAVY RAIN TO THE COASTS AND HEAVY SNOW TO
THE APPALACHIANS AND GREAT LAKES.  HOWEVER, THE GFS DOES NOT AMPLIFY THE TROUGH
THIS DEEPLY, AND INSTEAD, A SURFACE LOW SKIMS NEW ENGLAND.  THIS WOULD BRING
THE POTENTIAL OF HEAVY SNOW TO MAINE, BUT DUE TO THE UNCERTAINTY, NO HAZARDS
ARE INDICATED AT THIS TIME.  TO ADD TO THE UNCERTAINTY, THESE MODELS HAVE
FLIP-FLOPPED FROM THE PATTERN THEY WERE PREDICTING YESTERDAY.



THE MOST RECENT DROUGHT MONITOR, RELEASED OCTOBER 23, SHOWS A SLIGHT DECREASE
IN THE AREAL COVERAGE OF SEVERE DROUGHT, FROM 18.01% TO 18.0%.  THERE IS ALSO
THE LARGEST AMOUNT OF AREAL EXTENT WITHOUT ANY LEVEL OF DRYNESS SINCE DECEMBER
2011.

FORECASTER: KENNETH PELMAN

$$





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