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FXUS06 KWBC 231922
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED AUGUST 23 2017

6-10 DAY OUTLOOK FOR AUG 29 - SEP 02, 2017

TODAY`S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED MID-TROPOSPHERIC
FLOW PATTERN FOR NORTH AMERICA. AN AMPLIFIED PATTERN FOR THIS TIME OF YEAR IS
PREDICTED WITH A RIDGE EXPECTED OVER THE WESTERN CONUS AND MUCH OF MAINLAND
ALASKA, WHILE A POSITIVELY TILTED TROUGH IS ANTICIPATED OVER THE EAST-CENTRAL
CONUS FROM THE GREAT LAKES TO THE WEST-CENTRAL GULF COAST REGION. A TROUGH IS
PREDICTED OVER THE ALASKA PENINSULA AND THE EASTERN ALEUTIANS. THE
DETERMINISTIC SOLUTIONS FROM THE GFS AND ECMWF ARE IN BASICALLY GOOD AGREEMENT
WITH THE ENSEMBLE MEANS SOLUTIONS, ALTHOUGH AS IS TYPICALLY THE CASE, THE
DETERMINISTIC SOLUTIONS ARE MORE AMPLIFIED WITH MAIN CIRCULATION FEATURES. THE
LARGEST UNCERTAINTY WITH REGARD TO THE CURRENT MODEL SOLUTIONS IS IN REGARD TO
THE HANDLING OF A TROPICAL SYSTEM (THE REMNANTS OF TROPICAL DEPRESSION HARVEY)
WHICH IS FORECAST TO INTENSIFY OVER THE BAY OF CAMPECHE/SOUTHERN GULF OF
MEXICO), AND HOW IT INTERACTS WITH THE TROUGH FORECAST OVER THE EAST-CENTRAL
CONUS. THIS UNCERTAINTY IS REFLECTED IN THE ENSEMBLE SPAGHETTI CHARTS WHICH
INDICATE MODERATE SPREAD OVER MUCH OF THE FORECAST DOMAIN, BUT LARGE SPREAD
OVER THE EAST-CENTRAL CONUS. TODAY`S 500-HPA BLEND CHART DEPICTS NEAR TO ABOVE
NORMAL HEIGHTS OVER MOST OF THE WESTERN THIRD OF THE CONUS, SOUTHERN FLORIDA,
EXTREME NORTHERN MAINE, AND NORTHEASTERN MAINLAND ALASKA, WHILE NEAR TO BELOW
NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.

BELOW NORMAL HEIGHTS TILT THE ODDS TO BELOW NORMAL TEMPERATURES FOR MUCH OF THE
EASTERN TWO-THIRDS OF THE CONUS AND THE ALEUTIANS. NEAR TO ABOVE NORMAL HEIGHTS
FAVOR ABOVE NORMAL TEMPERATURES FOR MAINE, FLORIDA, AND THE WESTERN THIRD OF
THE CONUS. ANOMALOUS SOUTH-SOUTHEASTERLY FLOW ENHANCE PROBABILITIES FOR ABOVE
NORMAL TEMPERATURES FOR MUCH OF WESTERN MAINLAND ALASKA AND THE ALASKA
PANHANDLE.

THE TROUGH FORECAST OVER THE EAST-CENTRAL U.S. FAVORS ABOVE NORMAL
PRECIPITATION FOR THE SOUTHEASTERN CONUS. MONSOONAL FLOW TILTS THE ODDS TO
ABOVE NORMAL PRECIPITATION FOR PARTS OF THE SOUTHWESTERN CONUS. ANOMALOUS
NORTHERLY FLOW, ALONG WITH SINKING MOTION ON THE REAR SIDE OF THE TROUGH
FORECAST OVER THE EAST-CENTRAL U.S. ENHANCE PROBABILITIES FOR BELOW NORMAL
PRECIPITATION FOR MUCH OF THE CENTRAL CONUS. ABOVE NORMAL HEIGHTS FAVORS BELOW
NORMAL PRECIPITATION FOR THE NORTHWEST U.S. AND PARTS OF MAINE. THE TROUGH
PREDICTED OVER THE ALASKA PENINSULA TILT THE ODDS TO ABOVE NORMAL PRECIPITATION
FOR SOUTHERN MAINLAND ALASKA AND THE ALASKA PANHANDLE, WHILE ANOMALOUS
NORTHEASTERLY FLOW FAVORS BELOW NORMAL PRECIPITATION FOR THE WESTERN ALEUTIANS.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 20% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 10% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 30%
OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF YESTERDAY`S 12Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
FAIRLY GOOD MODEL AGREEMENT ON AN AMPLIFIED FLOW PATTERN OVER MUCH OF THE
FORECAST DOMAIN.

8-14 DAY OUTLOOK FOR AUG 31 - SEP 06, 2017

DURING THE WEEK-2 PERIOD LITTLE OVERALL CHANGE IS EXPECTED WITH REGARD TO THE
MID-LEVEL FLOW PATTERN EXPECTED OVER THE FORECAST DOMAIN. THE ONE EXCEPTION IS
THE SOUTHERN EXTENT OF THE TROUGH FORECAST OVER THE EAST-CENTRAL CONUS WHICH IS
ANTICIPATED TO LIFT OUT TO THE NORTHEAST AS THE REMAINS OF THE TROPICAL SYSTEM
FORECAST OVER THE GULF OF MEXICO GETS CAUGHT UP IN THE MID-LATITUDE WESTERLIES.
THE ENSEMBLE SPAGHETTI CHARTS INDICATE MODERATE TO LARGE SPREAD OVER MOST OF
THE FORECAST DOMAIN. THE LARGEST SPREAD IS IN REGARD TO THE AMPLITUDE OF THE
TROUGH FORECAST OVER THE EAST-CENTRAL CONUS, AND THE POSSIBILITY OF TROUGH
ENERGY UNDERCUTTING THE RIDGE FORECAST OVER THE WESTERN CONUS. TODAY`S 500-HPA
BLEND CHART INDICATES ABOVE NORMAL HEIGHTS OVER MOST OF THE WESTERN THIRD OF
THE CONUS, FLORIDA, AND EXTREME NORTHEASTERN MAINLAND ALASKA, WHILE BELOW
NORMAL HEIGHTS ARE EXPECTED OVER THE REMAINDER OF THE FORECAST DOMAIN.

THE EXPECTED TEMPERATURE AND PRECIPITATION ANOMALIES FOR WEEK 2 ARE VERY
SIMILAR TO THOSE PREDICTED FOR THE 6-10 DAY PERIOD, ALTHOUGH A SOMEWHAT WETTER
PATTERN IS ANTICIPATED FOR PARTS OF THE NORTHEAST DURING WEEK 2.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 10% OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY`S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF YESTERDAY`S 12Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 10, 5% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 10% OF YESTERDAY`S 12Z CANADIAN ENSEMBLE MEAN CENTERED
ON DAY 10


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO FAIRLY GOOD AGREEMENT AMONG THE ENSEMBLE MEANS.

FORECASTER: RANDY S

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 21

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:
19530813 - 20050819 - 19660903 - 19800903 - 20090821


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:
19530813 - 20090822 - 20090827 - 19920809 - 19660902


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 29 - SEP 02, 2017

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    N
W MONTANA   A    B     E MONTANA   A    N     WYOMING     A    N
UTAH        A    A     ARIZONA     A    A     COLORADO    B    N
NEW MEXICO  N    B     N DAKOTA    A    B     S DAKOTA    B    B
NEBRASKA    B    B     KANSAS      B    B     OKLAHOMA    B    B
N TEXAS     B    B     S TEXAS     B    B     W TEXAS     B    B
MINNESOTA   B    B     IOWA        B    B     MISSOURI    B    B
ARKANSAS    B    N     LOUISIANA   B    A     WISCONSIN   B    B
ILLINOIS    B    B     MISSISSIPPI B    A     MICHIGAN    B    B
INDIANA     B    N     OHIO        B    N     KENTUCKY    B    A
TENNESSEE   B    A     ALABAMA     B    A     NEW YORK    B    N
VERMONT     N    B     NEW HAMP    N    N     MAINE       A    B
MASS        N    N     CONN        N    N     RHODE IS    N    N
PENN        B    A     NEW JERSEY  B    A     W VIRGINIA  B    A
MARYLAND    B    A     DELAWARE    B    A     VIRGINIA    B    A
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A
FL PNHDL    N    A     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN B    N     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 AUG 31 - SEP 06, 2017

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