Prognostic Meteorological Discussion
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FXUS06 KWBC 262004
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED NOVEMBER 26 2014

6-10 DAY OUTLOOK FOR DEC 02 - 06 2014

THERE IS GOOD AGREEMENT AMONG TODAY`S MODEL FORECASTS OF THE 6-10 DAY MEAN
500-HPA HEIGHTS OVER NORTH AMERICA. THE MODELS PREDICT MOSTLY ZONAL FLOW AT
500-HPA OVER MUCH OF THE CONUS WITH A TENDENCY FOR AN ELONGATED REGION OF ABOVE
NORMAL HEIGHTS FROM THE GREAT PLAINS THROUGH MUCH OF THE ATLANTIC OCEAN.
HEIGHTS OVER NORTHERN QUEBEC AND HUDSON BAY ARE CONSIDERABLY BELOW NORMAL,
GIVING A POSITIVE AO/NAO LOOK TO THE FLOW PATTERN AND A STRONG JET NEAR OR JUST
NORTH OF THE U.S./CANADIAN BORDER. THE ECMWF KEEPS MORE OF A MEAN SOUTHERN
STREAM TROUGH JUST OFF SHORE OF SOUTHERN CALIFORNIA THAN THE GEFS.  A SHARP
GRADIENT IN TEMPERATURE IS PREDICTED TO DEVELOP NEAR THE ENHANCED JET ALONG THE
NORTHERN BORDER OF THE CONUS, AND SURFACE FORECASTS CONTINUE TO SHOW THE
LIKELIHOOD OF SHALLOW COLD AIR MASSES INFLUENCING THE NORTHERN CONUS IN THE
6-10 DAY PERIOD.  THIS MEANS THAT IN SPITE OF QUITE GOOD AGREEMENT ON THE 6-10
DAY MEAN FLOW AT 500-HPA BETWEEN MODELS, THERE IS MUCH UNCERTAINTY IN THE
FORECAST RELATING TO TEMPERATURES OVER THE NORTHER CONUS. MODELS AGREE ON
MOSTLY BELOW NORMAL 500-HPA HEIGHTS OVER EASTERN ALASKA THROUGH THE PERIOD.

ABOVE-NORMAL HEIGHTS OVER THE EASTERN HALF OF THE CONUS LEAD TO ENHANCED
CHANCES OF ABOVE-NORMAL TEMPERATURES, ESPECIALLY IN THE SOUTHEAST. CONFIDENCE
IN THE NORTH IS DIMINISHED DUE TO SHORT-LIVED, SHALLOW COLD AIR MASSES THAT ARE
EXPECTED TO LEAD TO CONSIDERABLE VARIATIONS IN DAY-TO-DAY TEMPERATURES WITHIN
THE 6-10 DAY PERIOD. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE
PACIFIC NORTHWEST EASTWARD TO THE UPPER MISSISSIPPI VALLEY WHERE THE COLD AIR
MAY PREDOMINATE WITHIN THE PERIOD. MOST MODELS PREDICT RELATIVELY MILD AIR OVER
MUCH OF THE WEST, IN SPITE OF THE FORECAST OF A STRONG TROUGH THAT WILL
INFLUENCE THE SOUTHWEST EARLY IN THE PERIOD, FAVORING ABOVE-NORMAL
TEMPERATURES. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR EASTERN AND CENTRAL
ALASKA UNDER BELOW-NORMAL 500-HPA HEIGHTS, ALTHOUGH NEAR- TO ABOVE-NORMAL
TEMPERATURES ARE FAVORED NEAR THE COASTS WHERE ABOVE-NORMAL SEA SURFACE
TEMPERATURES ARE EXPECTED TO MODERATE TEMPERATURES.

ENHANCED WESTERLY FLOW OVER THE PACIFIC LEADS TO ELEVATED CHANCES FOR
ABOVE-MEDIAN PRECIPITATION AMOUNTS FOR MUCH OF THE SOUTHWESTERN CONUS. THE
EXPECTED NORTH PACIFIC STORM TRACK IS PREDICTED TO BE FARTHER NORTH IN MOST OF
TODAY`S MODELS THAN THEY WERE YESTERDAY, LEADING TO UNCERTAIN CONDITIONS FOR
THE PACIFIC NORTHWEST, AND ENHANCED CHANCES OF ABOVE-MEDIAN PRECIPITATION
AMOUNTS FOR THE ALASKA PANHANDLE. EXPECTED SOUTHERLY LOW-LEVEL FLOW SHOULD OPEN
MUCH OF THE EASTERN CONUS TO MOISTURE FROM THE GULF OF MEXICO, ENHANCING
CHANCES FOR ABOVE-MEDIAN PRECIPITATION. A RELATIVELY NARROW REGION OF NEAR- TO
BELOW-MEDIAN PRECIPITATION IS EXPECTED TO THE LEE OF THE ROCKIES WHERE LIMITED
MOISTURE SUPPLY IN ZONAL FLOW MAY REDUCE PRECIPITATION AMOUNTS. THE GFS FAVORS
BELOW-MEDIAN PRECIPITATION AMOUNTS IN MUCH OF ALASKA EXCEPT FOR SOUTHERN
PORTIONS OF THE STATE.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 40% OF TODAY`S 6Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,
10% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 20% OF TODAY`S 0Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8


MODEL OF THE DAY: 6Z GEFS ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT ON THE 500-HPA HEIGHTS, BUT CONSIDERABLE UNCERTAINTY
ASSOCIATED WITH THE POSSIBLE INFLUENCE OF COLD AIR EXPECTED WITHIN THE PERIOD
OVER THE NORTHERN CONUS.

8-14 DAY OUTLOOK FOR DEC 04 - 10 2014

THE AGREEMENT AMONG MODELS IS WORSE IN THE 8-14 DAY MEAN THAN IN 6-10 DAY
PERIOD. THE GEFS AND CANADIAN MODELS BUILD A RIDGE OVER WESTERN NORTH AMERICA,
WHILE THE ECMWF KEEPS THE FLOW ZONAL AND SIMILAR TO THE 6-10 DAY PERIOD. THE
GEFS AND CANADIAN SOLUTIONS SUGGEST AN INCREASED CHANCE OF A NORTHERLY
COMPONENT TO THE 500-HPA FLOW OVER CENTRAL NORTH AMERICA AND INCREASES THE
LIKELIHOOD OF COLD AIR PUSHING IN TO THE EASTERN AND CENTRAL CONUS. SURFACE
TEMPERATURES FROM THE MODELS SUGGEST THAT THIS WILL PREDOMINATELY BE RELATIVELY
MILD AIR OF PACIFIC ORIGIN, SO THE CHANCES OF NEAR TO ABOVE-NORMAL TEMPERATURES
ARE ENHANCED, ALTHOUGH TEMPERATURE CONDITIONS THROUGHOUT THE NORTHERN CONUS ARE
UNCERTAIN.  CONDITIONS IN ALASKA DURING WEEK-2 ARE EXPECTED TO BE SIMILAR TO
THE 6-10 DAY PERIOD.

AS IN YESTERDAY`S MODEL SOLUTIONS, THE TROUGH INITIALLY NEAR THE SOUTHERN
CALIFORNIA COAST AT THE START OF THE 8-14 DAY PERIOD CONTINUES TO BE
CONSIDERABLY MORE PROGRESSIVE IN GEFS SOLUTIONS THAN THE ECMWF ENSEMBLES
SUGGEST. GIVEN THAT THE MODELS HAVE BEEN TRENDING SLOWER ON THIS SYSTEM, THE
CHANCES OF ABOVE-MEDIAN PRECIPITATION AMOUNTS REMAIN ELEVATED IN PARTS OF THE
SOUTHWEST FOR THE 8-14 DAY PERIOD. BUILDING 500-HPA HEIGHTS PREDICTED BY THE
GEFS AND CANADIAN MODELS POINT TO DRIER CONDITIONS IN THE 8-14 DAY PERIOD THAN
FOR 6-10 DAYS AND ENHANCED CHANCES OF BELOW-MEDIAN PRECIPITATION FOR MOST OF
THE REMAINDER OF THE WEST. AN EXPECTED ENHANCED NORTH PACIFIC STORM TRACK
INCREASES THE ODDS OF ABOVE-MEDIAN PRECIPITATION ALONG THE PACIFIC COAST FROM
SOUTHEASTERN ALASKA TO PARTS OF WASHINGTON STATE. ELSEWHERE, THE PRECIPITATION
OUTLOOK FOR 8-14 DAYS REMAINS SIMILAR TO THE 6-10 DAY OUTLOOK, ALTHOUGH THE
CONFIDENCE AND AREA OF ABOVE-MEDIAN PRECIPITATION AMOUNTS IN THE EASTERN CONUS
IS DIMINISHED DUE TO THE INCREASING CHANCES OF DRY NORTHWESTERLY UPPER-LEVEL
FLOW.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 50% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON
DAY 11, AND 10% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO UNCERTAINTIES ASSOCIATED WITH AN ANTICIPATED BUILDING RIDGE IN WESTERN NORTH
AMERICA.

FORECASTER: DAVE UNGER

NOTES:


AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.

THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS
THE SAME AS THAT IN THE TABLES: A-ABOVE   N-NEAR NORMAL   B-BELOW

THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "F").  LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A).  PROBABILITY OF N IS
ALWAYS < 40%.

THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "INCHES").  LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A).  PROBABILITY OF N IS
ALWAYS < 40%.

IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL
BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY
EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY
SEASONS.  IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A
FORECAST OF LITTLE OR NO PRECIPITATION.

THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN
THE CLIMATE OUTLOOKS.

THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON
DECEMBER 18

ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19721129 - 19911203 - 19571121 - 19771130 - 19781128


ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19721128 - 19571121 - 19931105 - 19911202 - 20081203


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 02 - 06 2014

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    N     OREGON      N    N     NRN CALIF   A    A
SRN CALIF   A    A     IDAHO       N    N     NEVADA      A    A
W MONTANA   B    B     E MONTANA   B    B     WYOMING     N    B
UTAH        A    A     ARIZONA     A    A     COLORADO    A    B
NEW MEXICO  A    A     N DAKOTA    B    B     S DAKOTA    B    B
NEBRASKA    N    B     KANSAS      A    B     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    B
MINNESOTA   B    N     IOWA        N    A     MISSOURI    A    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   N    A
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A
MASS        A    A     CONN        A    A     RHODE IS    A    A
PENN        A    A     NEW JERSEY  A    A     W VIRGINIA  A    A
MARYLAND    A    A     DELAWARE    A    A     VIRGINIA    A    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    B
AK ALEUTIAN A    N     AK WESTERN  N    B     AK INT BSN  B    B
AK S INT    N    B     AK SO COAST N    N     AK PNHDL    A    A



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 04 - 10 2014

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    N     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B
UTAH        A    A     ARIZONA     A    A     COLORADO    A    B
NEW MEXICO  A    N     N DAKOTA    N    B     S DAKOTA    N    B
NEBRASKA    A    B     KANSAS      A    B     OKLAHOMA    A    B
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    B
MINNESOTA   N    B     IOWA        N    B     MISSOURI    A    N
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   N    B
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A
MASS        A    A     CONN        A    A     RHODE IS    A    A
PENN        A    A     NEW JERSEY  A    A     W VIRGINIA  A    A
MARYLAND    A    A     DELAWARE    A    A     VIRGINIA    A    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    N    A     FL PENIN    N    A     AK N SLOPE  N    B
AK ALEUTIAN A    N     AK WESTERN  N    B     AK INT BSN  B    B
AK S INT    N    N     AK SO COAST N    A     AK PNHDL    A    A

                           LEGEND
TEMPS WITH RESPECT TO NORMAL     PCPN WITH RESPECT TO MEDIAN
A - ABOVE   N  - NEAR NORMAL     A - ABOVE   N - NEAR MEDIAN
B - BELOW                        B - BELOW

THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.

FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.

$$



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