Prognostic Meteorological Discussion
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FXUS06 KWBC 221901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI AUGUST 22 2014

6-10 DAY OUTLOOK FOR AUG 28 - SEP 01, 2014

TODAY`S MODELS ARE IN FAIR AGREEMENT ON THE 500-HPA PATTERN FORECAST FOR THE
6-10 DAY PERIOD. ALL MODELS ARE FORECASTING POSITIVE 500-HPA HEIGHT ANOMALIES
OVER THE NORTHERN PACIFIC, EXTENDING ACROSS THE ALEUTIANS. UNLIKE THE PAST
SEVERAL DAYS, TODAY`S ECMWF AND CANADIAN ENSEMBLES ARE NO LONGER FORECASTING
THESE ANOMALIES TO EXTEND INTO THE WESTERN U.S. RATHER, THE PATTERN IS SHIFTED
TO THE WEST IN THESE MODELS, WITH A TROUGH CENTERED NEAR THE WEST COAST. THE
LATEST GFS ENSEMBLE, HOWEVER, IS STILL FORECASTING THE TROUGH FURTHER EAST,
WITH NEGATIVE HEIGHT ANOMALIES CENTERED OVER THE MIDDLE OF THE CONUS, AND
RIDGING EXTENDING INTO THE WESTERN CONUS. THIS UNCERTAINTY IN THE WEST IS ALSO
INDICATED BY LARGE SPREAD IN THE SPAGHETTI DIAGRAMS FOR TODAY`S ECMWF AND
CANADIAN ENSEMBLES. BECAUSE THE GFS ENSEMBLES HAVE HAD MUCH BETTER RUN-TO-RUN
CONTINUITY, IT IS FAVORED IN TODAY`S MANUAL 500-HPA BLEND. THE 6Z GFS
DETERMINISTIC RUN WAS ALSO INCLUDED SINCE IT`S CONSISTENT WITH THE PATTERN
FORECAST BY THE GFS ENSEMBLE, AND ADDS SOME AMPLITUDE TO THE RESULTING BLEND.

THE ANOMALOUS RIDGING OVER THE GULF OF ALASKA FAVORS ABOVE NORMAL TEMPERATURES
IN SOUTHERN ALASKA AND THE ALASKAN PANHANDLE. OFFSHORE WINDS ALSO FAVOR ABOVE
NORMAL TEMPERATURES IN PARTS OF OREGON, CALIFORNIA, AND THE SOUTHWEST. MODELS
ARE IN FAIRLY 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.

AN ABUNDANCE OF STORM SYSTEM ACTIVITY FORECAST IN ALASKA STRONGLY FAVORS ABOVE
MEDIAN PRECIPITATION FOR MOST OF THE STATE. ANOMALOUS HIGH PRESSURE,
POTENTIALLY EXTENDING INTO THE PACIFIC NORTHWEST, ENHANCES THE CHANCES FOR
BELOW MEDIAN PRECIPITATION THERE. THE 500-HPA PATTERN IS FORECAST TO BE
UNFAVORABLE FOR MONSOON ACTIVITY, INCREASING THE LIKELIHOOD FOR BELOW MEDIAN
PRECIPITATION IN THE SOUTHWEST. WITH NEGATIVE HEIGHT ANOMALIES CENTERED OVER
THE CENTRAL PLAINS, ABOVE MEDIAN PRECIPITATION IS FAVORED ALONG AND EAST OF THE
ANOMALOUS TROUGH AXIS. THE LATEST MODEL GUIDANCE FOR THE TROPICAL SYSTEM
CURRENTLY IN THE CARIBBEAN SUGGESTS THAT THE STORM WILL DEVELOP INTO A TROPICAL
STORM/HURRICANE, BUT MOST MODELS FORECAST THE STORM TO RECURVE OUT TO SEA.
HOWEVER THERE IS STILL A LOT OF UNCERTAINTY IN THE TRACK, WITH SOME POTENTIAL
FOR THE STORM TO MAKE SOME LEVEL OF IMPACT ON THE SOUTHEASTERN U.S. BECAUSE OF
THIS POTENTIAL, PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION ARE HIGHER OVER
THE FLORIDA PENINSULA AND THE SOUTHEAST THAN YESTERDAY.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 40% OF TODAY`S 6Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 30% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 15% OF
TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 15% 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 30 - SEP 05, 2014

THE FORECAST CIRCULATION FOR WEEK-2 IS EXPECTED TO BE VERY SIMILAR TO THAT IN
THE 6-10 DAY PERIOD. 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.
NEGATIVE HEIGHT ANOMALIES ARE EXPECTED TO BE SHIFTED SLIGHTLY WEST COMPARED TO
THE 6-10 DAY PERIOD, FAVORING BELOW NORMAL TEMPERATURES FROM THE PACIFIC
NORTHWEST INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS. THE POTENTIAL FOR SOME
HEIGHTS TO RISEIN THE NORTHEAST INCREASES THE LIKELIHOOD OF ABOVE NORMAL
TEMPERATURES THERE. THE PRECIPITATION PROBABILITY FORECAST IS VERY SIMILAR TO
THAT OF THE 6-10 DAY PERIOD.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 50% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, AND 50% 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, RECENT 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:
19800821 - 19680831 - 20020809 - 19510825 - 20030805


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:
19800820 - 19680830 - 20020808 - 19510826 - 20080831


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 28 - SEP 01, 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 30 - SEP 05, 2014

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    B     OREGON      B    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    A
UTAH        B    B     ARIZONA     N    B     COLORADO    B    N
NEW MEXICO  A    B     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    B    A     KANSAS      N    A     OKLAHOMA    A    N
N TEXAS     A    N     S TEXAS     A    B     W TEXAS     A    B
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    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A
MASS        A    A     CONN        A    A     RHODE IS    A    A
PENN        N    A     NEW JERSEY  A    A     W VIRGINIA  N    A
MARYLAND    N    A     DELAWARE    A    A     VIRGINIA    N    A
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  B    A
AK ALEUTIAN A    N     AK WESTERN  B    N     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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