Prognostic Meteorological Discussion
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FXUS06 KWBC 021931
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED SEPTEMBER 02 2015

6-10 DAY OUTLOOK FOR SEP 08 - 12 2015

TODAY`S MODEL SOLUTIONS ARE IN ONLY FAIR AGREEMENT ON THE PREDICTED 500-HPA
FLOW PATTERN OVER NORTH AMERICA AND VICINITY. THE ENSEMBLE MEAN SOLUTIONS FROM
THE GFS, ECMWF, AND CANADIAN FORECAST TROUGHS OVER THE BERING SEA OR WESTERN
ALASKA. A LOW AMPLITUDE CIRCULATION PATTERN IS EXPECTED OVER THE NORTHERN CONUS
WITH A BROADLY CYCLONIC FLOW ANTICIPATED OVER THE CENTRAL AND EASTERN PARTS OF
THE NATION. A SUB-TROPICAL RIDGE IS FORECAST TO DOMINATE THE SOUTHERN CONUS
WITH A WEAKNESS IN THE RIDGE PREDICTED FOR THE SOUTHEASTERN U.S. THE ENSEMBLE
SPAGHETTI CHARTS INDICATE MODERATE SPREAD ACROSS MOST OF THE FORECAST DOMAIN
MOSTLY RELATED TO TIMING DIFFERENCES IN THE LOW AMPLITUDE FLOW EXPECTED OVER
THE NORTHERN U.S. THE SPREAD IS PARTIALLY DUE TO THE UNCERTAINTIES ASSOCIATED
WITH TROPICAL SYSTEMS IN THE PACIFIC RECURVING AND ENTERING THE MID-LATITUDES
DURING THE PERIOD. TODAY`S HEIGHT BLEND DEPICTS VERY SMALL HEIGHT ANOMALIES
ACROSS MOST OF THE FORECAST DOMAIN. HEIGHTS ARE ANTICIPATED TO BE SLIGHLY ABOVE
NORMAL OVER THE WESTERN, AND MOST OF THE NORTHEASTERN CONUS, AND SLIGHTLY BELOW
NORMAL OVER THE NORTH-CENTRAL AND SOUTHEASTERN CONUS. NEGATIVE HEIGHT ANOMALIES
ARE FORECAST OVER MUCH OF ALASKA EXCEPT FOR THE NORTHWESTERN PART OF THE STATE
AND THE ALASKA PANHANDLE WHERE SLIGHTLY ABOVE NORMAL HEIGHTS ARE ANTICIPATED.

BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE NORTHERN HIGH PLAINS IN
ASSOCIATION WITH THE AREA OF NEAR TO BELOW NORMAL HEIGHTS ANTICIPATED OVER THE
REGION. ABOVE NORMAL TEMPERATURES ARE FAVORED OVER MOST OF THE EASTERN AND
SOUTH-CENTRAL CONUS DUE TO WEAK ANOMALOUS SOUTHEASTERLY FLOW AND THE RIDGE
EXPECTED TO BUILD OVER MUCH OF THE SOUTHERN CONUS. A WEAKNESS IN THIS RIDGE
OVER THE SOUTHEAST CREATES HIGH UNCERTAINTY IN THE FORECAST FOR THIS REGION.
ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE ALSO INDICATED FOR MUCH
OF SOUTHERN ALASKA AHEAD OF THE TROUGH PREDICTED OVER THE BERING SEA AND THE
ALEUTIANS. ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO BELOW NORMAL TEMPERATURES
FOR THE NORTH SLOPE OF ALASKA. PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE
ENHANCED ALONG THE WEST COAST OF THE CONUS DUE IN PART TO ABOVE NORMAL SSTS
CURRENTLY OBSERVED IN ADJACENT WATERS.

THERE ARE ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE
CENTRAL AND EASTERN CONUS DUE TO THE BROADLY CYCLONIC FLOW EXPECCTED OVER THESE
REGIONS. ABOVE NORMAL HEIGHTS ENHANCE PROBABILITIES FOR BELOW MEDIAN
PRECIPITATION FOR THE NORTHWESTERN CONUS AND NORTHWESTERN ALASKA. THE
SUB-TROPICAL RIDGE FORECAST OVER THE SOUTHERN CONUS TILT THE ODDS TO BELOW
MEDIAN PRECIPITATION FOR PARTS OF SOUTHERN TEXAS AND SOUTHERN FLORIDA.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 25% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON
DAY 8, 10% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 10% OF
YESTERDAY`S 12Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 7


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO
ONLY FAIR AGREEMENT AMONG THE MODEL SOLUTIONS, SMALL HEIGHT ANOMALIES, AND
MODERATE SPREAD AMONG THE ENSEMBLE MEMBERS.



8-14 DAY OUTLOOK FOR SEP 10 - 16 2015

TODAY`S WEEK-TWO MODEL SOLUTIONS GENERALLY EXHIBIT LARGE SPREAD AND UNCERTAINTY
FOR MUCH OF THE FORECAST DOMAIN, ALTHOUGH THERE IS FAIRLY GOOD AGREEMENT THAT A
TROUGH WILL BE LOCATED OVER THE EAST-CENTRAL CONUS. ELSEWHERE, TIMING
DIFFERENCES AMONG ENEMBLE MEMBERS LEADS TO RELATIVLY LARGE SPREAD. THE TROUGH
PREDICTED OVER THE EAST-CENTRAL CONUS IS FORECAST TO SUPPRESS THE SUB-TROPICAL
RIDGE TO THE GULF OF MEXICO. AGREEMENT IS SOMEWHAT BETTER OVER ALASKA, AS MOST
MODEL SOLUTIONS AGREE IN FORECASTING A TROUGH NEAR THE WESTERN PART OF THE
STATE AND A RIDGE NEAR THE PANHANDLE AND SOUTHEASTERN ALASKA. THE BLENDED
HEIGHT CHART INDICATES NEAR TO BELOW NORMAL HEIGHTS OVER THE EAST-CENTRAL CONUS
AND MUCH OF ALASKA, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE ANTICIPATED
ELSEWHERE.

BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE NORTHERN AND CENTRAL
PLAINS DUE TO THE TROUGH ANTICIPATED OVER THE EAST-CENTRAL PART OF THE NATION.
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED FOR THE EAST
COAST, SOUTHERN ALASKA, AND THE ALASKA PANHANDLE (DUE TO ANOMALOUS SOUTHERLY
FLOW), ALONG THE GULF COAST (DUE TO ABOVE NORMAL SEA-SURFACE TEMPERATURES) AND
OVER THE WESTERN CONUS (DUE TO ABOVE NORMAL HEIGHTS). BELOW NORMAL HEIGHTS AND
WEAK ANOMALOUS NORTHERLY FLOW ENHANCE PROBABILITIES FOR BELOW NORMAL
TEMPERATURES FOR THE NORTH SLOPE OF ALASKA.

THE TROUGH PREDICTED OVER THE EAST-CENTRAL CONUS FAVORS ABOVE MEDIAN
PRECIPITATION FOR THE EASTERN QUARTER AND SOUTHERN TIER OF THE CONUS. THERE ARE
ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR MUCH OF SOUTHERN
ALASKA IN ASSOCIATION WITH THE TROUGH PREDICTED OVER THE BERING SEA/WESTERN
ALASKA. BELOW MEDIAN PRECIPITATION IS FAVORED FOR THE NORTHWESTERN CONUS
CONSISTENT WITH GEFS REFORECAST GUIDANCE. ANOMALOUS NORTHERLY FLOW TILTS THE
ODDS TO BELOW MEDIAN PRECIPITATION FOR PARTS OF NORTHWESTERN ALASKA.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 10% OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 25% OF TODAY`S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF YESTERDAY`S 12Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 10, 15% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 15% OF YESTERDAY`S 12Z CANADIAN ENSEMBLE MEAN CENTERED
ON DAY 10


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO LARGE MODEL SPREAD AND UNCERTAINTY.

FORECASTER: RANDY SCHECHTER

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 17

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:
19600830 - 19830907 - 19520906 - 20040916 - 19950815


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:
20040915 - 19600901 - 19830907 - 19950816 - 19520908


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 08 - 12 2015

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 10 - 16 2015

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

                           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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