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FXUS06 KWBC 211907
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU AUGUST 21 2014

6-10 DAY OUTLOOK FOR AUG 27 - 31 2014

TODAYS MODELS ARE IN FAIR AGREEMENT ON THE 500-HPA PATTERN FORECAST FOR THE
6-10 DAY PERIOD. ALL MODELS AGREE ON POSITIVE HEIGHT ANOMALIES CENTERED OVER
THE NORTHERN PACIFIC, EXTENDING ACROSS THE ALEUTIANS SOUTHEASTWARD TO THE
WESTERN CONUS. THESE ANOMALIES HAVE BEEN WEAKER IN RECENT ENSEMBLE RUNS,
HOWEVER, INDICATING A POTENTIAL FOR A SIGNIFICANT CHANGE IN THE PATTERN, AS
THESE POSITIVE HEIGHT ANOMALIES HAVE BEEN PERSISTING FOR WEEKS. A BROAD TROUGH
IS FORECAST OVER CENTRAL NORTH AMERICA WITH SOME DOWNSTREAM RIDGING EXPECTED
OVER FAR EASTERN CANADA. THESE POSITIVE HEIGHT ANOMALIES HAVE ALSO BEEN WEAKER
IN RECENT FORECASTS. OVERALL THE 500-HPA PATTERN FORECAST OVER NORTH AMERICA
HAS BEEN TRENDING TOWARD A MORE ZONAL PATTERN. TODAYS MANUAL 500-HPA HEIGHT
BLEND FAVORS THE 6Z GFS ENSEMBLE, WHICH HAS HAD MORE RUN TO RUN CONSISTENCY
THAN THE ECMWF OR CANADIAN ENSEMBLES. RECENT DETERMINSTIC GFS AND ECMWF RUNS
HAVE BEEN FAIRLY INCONSISTENT OVER TIME, SO THEY WERE LESS FAVORED IN TODAYS
BLEND.

THE ANOMALOUS RIDGING OVER THE GULF OF ALASKA FAVORS ABOVE-NORMAL TEMPERATURES
IN ALASKA AND ALONG THE WEST COAST. FORECAST PROBABILITIES ARE LOWER COMPARED
TO YESTERDAY BECAUSE OF THE DEAMPLIFICATION OF THE FORECAST HEIGHT ANOMALIES.
MODELS ARE IN GOOD AGREEMENT ON ANOMALOUS TROUGHING OVER THE NORTHERN PLAINS
AND ROCKIES. ALL FORECAST TOOLS ARE IN REASONABLY GOOD AGREEMENT ON THE
FORECAST TEMPERATURE PATTERN ACROSS THE CENTRAL AND EASTERN CONUS, WITH A MEAN
FRONTAL POSITION FORECAST FROM THE GREAT LAKES TOWARD THE SOUTHWESTERN U.S.
ABOVE NORMAL TEMPERATURES ARE FAVORED SOUTH OF THE FRONT, INCLUDING THE
SOUTHERN PLAINS, SOUTHEAST, AND EASTERN U.S.

WHILE THE EXTRATROPICAL PATTERN IS GENERALLY WELL AGREED UPON, MORE FORECAST
UNCERTAINTY IS INTRODUCED BY TROPICAL ACTIVITY IN THE ATLANTIC. A TROPICAL WAVE
IN THE ATLANTIC IS FORECAST TO MOVE WEST-NORTHWESTWARD TOWARD THE SOUTHEAST
COAST, POSSIBLY DEVELOPING INTO A NAMED TROPICAL CYCLONE. THERE IS A POTENTIAL
THIS SYSTEM MAY HAVE SOME IMPACT ON THE EASTERN U.S., ENHANCING THE ODDS OF
ABOVE-MEDIAN PRECIPITATION FOR THE GULF COAST, FLORIDA PENINSULA, AND SOUTHWEST
COAST, THOUGH THERE IS STILL A GREAT DEAL OF UNCERTAINTY.  THE PRECIPITATION
OUTLOOK ACROSS THE REMAINDER OF THE CONUS FOLLOWS FROM THE FORECAST
EXTRATROPICAL 500-HPA HEIGHT PATTERN ACROSS NORTH AMERICA. WITH NEGATIVE HEIGHT
ANOMALIES CENTERED OVER THE ROCKIES, ABOVE-MEDIAN (BELOW-MEDIAN) PRECIPITATION
IS FAVORED ALONG AND EAST OF THE AXIS (OVER THE PACIFIC NORTHWEST).

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


MODEL OF THE DAY: 6Z GFS ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
FAIRLY GOOD AGREEMENT AMONG THE MODELS AND TOOLS, OFFSET BY UNCERTAINTY DUE TO
EXPECTED TROPICAL STORM ACTIVITY THAT COULD IMPACT PARTS OF THE CONUS.

8-14 DAY OUTLOOK FOR AUG 29 - SEP 04, 2014

THE FORECAST CIRCULATION FOR WEEK-2 IS EXPECTED TO BE SIMILAR TO THAT IN THE
6-10 DAY PERIOD, THOUGH SOME RETROGRESSION IS EXPECTED. THE TROUGH IS NOW
FORECAST ALONG THE WEST COAST, AS OPPOSED TO THE CENTRAL PLAINS AND ROCKIES.
THE REST OF THE CONUS IS EXPECTED TO EXPERIENCE A FAIRLY ZONAL PATTERN. THE
TEMPERATURE PROBABILITY FORECAST IS SIMILAR TO THAT IN THE 6-10 DAY PERIOD,
WITH A FEW EXCEPTIONS. IN ALASKA, ANOMALOUS TROUGHING IS EXPECTED TO
INCREASINGLY FAVOR BELOW NORMAL TEMPERATURES FOR MUCH OF THE STATE. WITH A MORE
ZONAL PATTERN, A LARGER AREA OF THE CONUS IS EXPECTED TO EXPERIENCE INCREASED
CHANCES FOR NEAR NORMAL TEMPERATURES. THE PRECIPITATION PROBABILITY FORECAST IS
VERY SIMILAR TO THAT OF THE 6-10 DAY PERIOD, EXCEPT THE PATTERN OVER THE
SOUTHWEST IS EXPECTED TO BE LESS FAVORABLE FOR MONSOON ACTIVITY, ENHANCING THE
LIKELIHOOD OF BELOW MEDIAN PRECIPITATION THERE.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 40% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, AND 60% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED
ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO REASONABLE AGREEMENT AMONG MODEL TOOLS, OFFSET BY A LOW-AMPLITUDE FORECAST
PATTERN, RECENTLY POOR MODEL PERFORMANCE, AND UNCERTAINTY WITH RESPECT TO
TROPICAL ACTIVITY.

FORECASTER: MIKE CHARLES

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
SEPTEMBER 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:
19800819 - 20080901 - 20020809 - 19870810 - 19640820


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:
19800819 - 20080831 - 19870812 - 19560830 - 19810903


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 27 - 31 2014

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       B    B     NEVADA      A    N
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        B    N     ARIZONA     N    N     COLORADO    B    N
NEW MEXICO  A    N     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    B    A     KANSAS      N    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    N
MINNESOTA   B    A     IOWA        B    A     MISSOURI    A    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   B    A
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    B    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  A    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    N     AK SO COAST A    N     AK PNHDL    A    N



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 29 - SEP 04, 2014

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