Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXUS06 KWBC 252000
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 25 2016

6-10 DAY OUTLOOK FOR AUG 31 - SEP 04, 2016

TODAY`S 500-HPA HEIGHT MANUAL BLEND SHOWS A MORE AMPLIFIED PATTERN OVER THE
CONUS THAN FORECASTS ISSUED EARLIER THIS WEEK. A COHERENT WAVE PATTERN IS
DEPICTED FROM EAST ASIA AND THE NORTH PACIFIC EASTWARD ACROSS NORTH AMERICA.
ANOMALOUS RIDGING IS FORECAST OVER THE CENTRAL CONUS, WHILE ANOMALOUS TROUGHING
IS FORECAST OVER BOTH THE WEST COAST AND NEW ENGLAND. THE ECMWF SYSTEM IS GIVEN
SLIGHTLY HIGHER WEIGHTING BASED ON A BETTER TELECONNECTED PATTERN OVER THE
NORTH PACIFIC AND WESTERN NORTH AMERICA, THOUGH ASSOCIATED SURFACE FORECAST
TOOLS FROM THE VARIOUS ENSEMBLES ARE IN GOOD AGREEMENT.

ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER THE ENTIRE CENTRAL AND EASTERN
PORTIONS OF THE CONUS, WITH THE HIGHEST PROBABILITIES INDICATED NEAR THE
ANOMALOUS RIDGE AXIS FROM THE PLAINS TO THE SOUTHEAST. DYNAMICAL AND
STATISTICAL TOOLS ARE IN GOOD AGREEMENT ON A TREND TOWARD COOLER CONDITIONS
OVER MUCH OF THE NORTHWESTERN PORTION OF THE CONUS, WHERE ANOMALOUS TROUGHING
IS FORECAST. AS THE FORECAST PATTERN CONTINUES TO AMPLIFY SOMEWHAT OVER THE
WESTERN U.S. COMPARED TO YESTERDAY`S OUTLOOK, THE FORECAST TEMPERATURE GRADIENT
TIGHTENS AS WELL, WITH ENHANCED ODDS OF ABOVE-NORMAL TEMPERATURES INDICATED
OVER THE PLAINS, EXTENDING TO THE SOUTHWEST. MODELS ARE IN BETTER AGREEMENT ON
ANOMALOUS TROUGHING OVER FAR SOUTHEASTERN CANADA AND NEW ENGLAND, LEADING TO
ENHANCED PROBABILITIES OF NEAR-NORMAL TEMPERATURES, A COOLER SOLUTION THAN WAS
DEPICTED YESTERDAY.

THE PRECIPITATION OUTLOOK IS DERIVED MAINLY FROM THE REFORECAST-CALIBRATED GEFS
AND ECMWF SYSTEMS. ABOVE-MEDIAN PRECIPITATION IS FAVORED OVER THE
NORTHWESTERN-MOST CONUS NEAR THE FORECAST TROUGH AXIS, EXTENDING EASTWARD
ACROSS THE NORTHERN PLAINS. ABOVE-MEDIAN PRECIPITATION IS ALSO MORE LIKELY
ACROSS THE MIDWEST, GREAT LAKES, AND NORTHEAST, WITH AN EXTENSION SOUTHWARD
ALONG THE EASTERN SEABOARD TO THE GULF COAST. A KEY UNCERTAINTY OVER THE
SOUTHEAST IS THE PATH OF A TROPICAL DISTURBANCE FORECAST TO MOVE BETWEEN CUBA
AND FLORIDA OVER THE NEXT COUPLE OF DAYS. FORECAST MODELS SUGGEST THAT THIS
COULD IMPACT THE GULF COAST AND PARTS OF THE SOUTHEAST EARLY IN THE PERIOD.
REGARDLESS OF THE TROPICAL DEVELOPMENT AND TRACK OF THIS DISTURBANCE, MODELS
ARE IN FAIRLY GOOD AGREEMENT ON SURFACE TROUGHING OVER THE NORTHEASTERN GULF
COAST EARLY IN THE PERIOD. BELOW-MEDIAN RAINFALL IS LIKELY OVER PARTS OF THE
SOUTH-CENTRAL CONUS CENTERED ON THE SOUTHERN HIGH PLAINS. ANOMALOUS RIDGING AND
A FORECAST CIRCULATION NOT CONDUCIVE TO MONSOON RAINFALL OVER THE SOUTHWEST
SUPPORT THIS OUTLOOK.

WITH AN ANOMALOUS RIDGE AXIS FORECAST OVER ALASKA, ABOVE-NORMAL TEMPERATURES
ARE FAVORED, WHILE ABOVE-(BELOW-)MEDIAN PRECIPITATION IS FAVORED WEST (EAST) OF
THE RIDGE AXIS.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 15% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 10%
OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 40% OF TODAY`S 0Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 8, AND 20% OF TODAY`S OPERATIONAL 0Z ECMWF
CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG VARIOUS TOOLS, OFFSET SOMEWHAT BY UNCERTAINTY IN THE
PRECIPITATION OUTLOOK OVER THE SOUTHEAST.


8-14 DAY OUTLOOK FOR SEP 02 - 08 2016

THE 500-HPA HEIGHT MANUAL BLEND FOR WEEK-2 IS SLIGHTLY DEAMPLIFIED WITH RESPECT
TO THE 6-10 DAY PERIOD, BUT WITH NOTABLE EASTWARD PROGRESSION. THE VARIOUS
ENSEMBLE MEAN SOLUTIONS DIVERGE SIGNIFICANTLY, HOWEVER, WITH THE ECMWF AND
CANADIAN FAVORING A MORE PROGRESSIVE SOLUTION COMPARED TO THE GEFS.
TELECONNECTIONS UPON THE FORECAST POSITIVE HEIGHT ANOMALY OVER THE NORTHEAST
PACIFIC SEEM TO SUPPORT THE ECMWF AND CANADIAN SOLUTIONS. THIS, ALONG WITH
SLIGHTLY BETTER 500-HPA SKILL SCORES FROM THE ECMWF, LEADS TO THE MANUAL BLEND
BEING TILTED HEAVILY TOWARD THE ECMWF, WITH ANOMALOUS TROUGHING FAVORED OVER
MUCH OF THE WESTERN CONUS.

ABOVE-NORMAL TEMPERATURES ARE AGAIN FAVORED ACROSS THE CENTRAL AND EASTERN
CONUS UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. BELOW-NORMAL TEMPERATURES ARE
FAVORED OVER A LARGE REGION OF THE WESTERN CONUS, AS THE VARIOUS TOOLS REMAIN
IN DECENT AGREEMENT DESPITE THE CIRCULATION DIFFERENCES DISCUSSED ABOVE. AS IN
THE 6-10 DAY PERIOD, A SLIGHT WEAKNESS IN ABOVE-NORMAL PROBABILITIES IS
INDICATED FROM THE NORTHERN PLAINS SOUTHWARD THROUGH THE CENTRAL U.S.,
HIGHLIGHTING UNCERTAINTY WITH RESPECT TO POTENTIAL INCURSIONS OF CANADIAN AIR
MASSES DURING THE PERIOD.

THE PRECIPITATION OUTLOOK REMAINS UNCERTAIN, A NOT-UNCOMMON FEATURE OF EXTENDED
RANGE OUTLOOKS DURING LATE SUMMER AND EARLY AUTUMN. THE TROPICAL CYCLONE THREAT
IS EXPECTED TO TIME OUT BEFORE THE START OF THE PERIOD OVER THE SOUTHEAST,
THOUGH UNCERTAINTY LINGERS FARTHER NORTH DUE TO THE POTENTIAL EXTRATROPICAL
TRANSITION OF THE TROPICAL CYCLONE REMNANTS. THE FORECAST SOUTHWEST TO
NORTHEAST DIPOLE OF FORECAST PROBABILITIES OVER THE CENTRAL CONUS HINTS AT
ANOMALOUS NORTHWARD MOISTURE TRANSPORT AHEAD OF A MID-LATITUDE TROUGH.
ANOMALOUS TROUGHING ACROSS THE PACIFIC NORTHWEST FAVORS ABOVE-MEDIAN
PRECIPITATION OVER THAT REGION.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 10% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 60% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 20% OF
TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE
TO FAIR AGREEMENT AMONG FORECAST TOOLS OFFSET BY MODEL DISAGREEMENT AT 500-HPA.


FORECASTER: STEPHEN BAXTER

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 15

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:
19510901 - 19530902 - 19890907 - 20080905 - 19930830


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:
19510901 - 19890905 - 19930830 - 19520804 - 19890816


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 31 - SEP 04, 2016

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 02 - 08 2016

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

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.