Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS06 KWBC 261952
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON SEPTEMBER 26 2016

6-10 DAY OUTLOOK FOR OCT 02 - 06 2016

TODAY`S MODEL SOLUTIONS ARE IN GOOD AGREEMENT.  TROUGHING IS GENERALLY
PREDICTED OVER THE BERING SEA. SPLIT FLOW, WITH RIDGING OVER ALASKA AND
TROUGHING INTO THE WESTERN CONUS, FOLLOWED BY DOWNSTREAM RIDGING OVER THE
EASTERN CONUS ARE ALSO FEATURES COMMON TO THE AVAILABLE MODEL OUTPUTS. THE
AVAILABLE MODEL SOLUTIONS ALSO AGREE ON BELOW AVERAGE HEIGHTS OVER THE GULF OF
MEXICO. THE MODELS DIFFER ON HOW FAR SOUTH THE TROUGH IS LIKELY TO DIG OVER THE
SOUTHWEST, WITH THE EUROPEAN CENTER MODELS DEPICTING LOWER HEIGHTS FROM THE
SOUTHWEST TO THE GULF OF MEXICO. MANY GEFS RUNS HAVE A STRIP OF NEAR TO ABOVE
AVERAGE HEIGHTS OVER THE SOUTHERN PLAINS.

THE PATTERN DESCRIBED ABOVE FAVORS ABOVE AVERAGE TEMPERATURES FOR ALASKA, WITH
RIDGING AND ABOVE AVERAGE HEIGHTS OVER MUCH OF THE STATE. SOME LOW-LEVEL
EASTERLY FLOW COULD BRING TEMPERATURES CLOSER TO NORMAL FOR EASTERN ALASKA.
TROUGHING OVER THE WESTERN CONUS FAVORS BELOW NORMAL TEMPERATURES FROM THE WEST
COAST TO THE HIGH PLAINS. RIDGING ALOFT AND AT LOWER LEVELS FAVORS ABOVE NORMAL
TEMPERATURES FOR THE EASTERN HALF OF THE CONUS.

THE TROUGHING OVER THE BERING SEA SEEDS A POTENTIAL STORM TRACK INTO WESTERN
ALASKA, FAVORING ABOVE MEDIAN PRECIPITATION THERE, WHILE THE RIDGING OVER
MAINLAND ALASKA FAVORS BELOW MEDIAN PRECIPITATION. TROUGHING OVER THE WESTERN
CONUS OVER TOP OF LOW-LEVEL SOUTHERLY FLOW FAVORS ABOVE MEDIAN PRECIPITATION
FROM NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST TO THE UPPER MISSISSIPPI
VALLEY AND CENTRAL GREAT PLAINS. THE RIDGING OVER THE EASTERN CONUS FAVORS
BELOW MEDIAN PRECIPITATION. SOME MODELS ARE INDICATING THE POTENTIAL FOR A
TROPICAL CYCLONE TO MOVE INTO THE GULF OF MEXICO LATER IN THE PERIOD, WHILE THE
GEFS-BASED SOLUTIONS RECURVE THE DISTURBANCE OVER THE BAHAMAS WITH POTENTIAL
WEAKER IMPACTS TO FLORIDA. CORRESPONDINGLY, ODDS FOR BELOW MEDIAN PRECIPITATION
WERE REDUCED OVER THE GULF COAST WHILE ODDS FOR ABOVE MEDIAN PRECIPITATION OVER
MUCH OF FLORIDA WERE RETAINED FROM YESTERDAY`S OUTLOOK.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 10% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 15%
OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 8, AND 25% OF YESTERDAY`S 12Z EUROPEAN ENSEMBLE
MEAN CENTERED ON DAY 7


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG MODEL SOLUTIONS IN A MORE AMPLIFIED LONGWAVE PATTERN, BUT
INCREASED UNCERTAINTY DUE TO POTENTIAL TROPICAL CYCLONE ACTIVITY.


8-14 DAY OUTLOOK FOR OCT 04 - 10 2016

MODEL AGREEMENT ON THE PREDICTED 500-HPA PATTERN DECREASES FROM THE PRIOR
PERIOD, ALTHOUGH THE ENSEMBLE MEANS FROM THE GFS, EUROPEAN CENTER AND
ENVIRONMENT CANADA DEPICT GENERALLY SIMILAR PATTERNS. PREDICTED ANOMALIES ARE
WEAKER IN THE GFS-BASED AND CANADIAN MODELS. GEFS-BASED SOLUTIONS GENERALLY
HAVE A MORE EASTWARD TRACK FOR THE PREDICTED TROPICAL CYCLONE OVER THE
CARIBBEAN AND WESTERN ATLANTIC. UNCERTAINTY ABOUT TROPICAL CYCLONE TRACKS AT
THESE LEAD TIMES IS VERY HIGH COMPARED TO SHORTER-TERM OUTLOOKS, SO ONLY SLIGHT
SHIFTS IN THE OUTLOOK WERE INTRODUCED UNTIL A MORE CONSISTENT TRACK IS
INDICATED IN THE MODELS.

TROUGHING OVER THE BERING SEA, RIDING OVER MOST OF ALASKA, AND ABOVE NORMAL
SEA-SURFACE TEMPERATURES NEAR WESTERN ALASKA FAVOR ABOVE NORMAL TEMPERATURES
FOR THE STATE. A PREDICTED TROUGH OVER THE WESTERN CONUS FAVORS A CONTINUATION
OF BELOW NORMAL TEMPERATURES FROM THE WEST COAST TO THE NORTHERN PLAINS AND
SOUTHERN HIGH PLAINS. ABOVE NORMAL TEMPERATURES ARE FAVORED FROM THE GREAT
PLAINS TO THE EAST COAST UNDER RIDGING ALOFT. MODELS DO DISAGREE OVER THE
MIDWEST ON THE CERTAINTY OF ABOVE NORMAL TEMPERATURES WITH THE GEFS DEPICTING
COOLER, MORE PROGRESSIVE SOLUTIONS. BOTH GEFS AND EUROPEAN CENTER MODELS
INDICATE ABOVE NORMAL TEMPERATURES OVER THE SOUTHEAST, THOUGH THE EUROPEAN
CENTER MODEL HAS MUCH HIGHER ODDS.

THE TROUGH OVER THE BERING SEA FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH OF
WESTERN ALASKA. TROUGHING OVER THE WESTERN CONUS, THOUGH PREDICTED TO BE WEAKER
THAN DURING THE 6-10 DAY PERIOD, STILL FAVORS AN ACTIVE PATTERN FROM NORTHERN
CALIFORNIA TO THE CENTRAL PLAINS, THOUGH SOME PROGRESSION TO THE PATTERN
EXTENDS THE NORTHERN PORTIONS TO THE GREAT LAKES. BELOW MEDIAN PRECIPITATION IS
FAVORED ALONG THE APPALACHIANS, FROM THE SOUTHEAST TO THE LOWER GREAT LAKES.
WEAK TROUGHING OVER THE WESTERN ATLANTIC FAVORS ABOVE MEDIAN PRECIPITATION FOR
FLORIDA AND PORTIONS OF THE EAST COAST.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 20% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 25% OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY`S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 10% OF YESTERDAY`S 12Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 10


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE TEMPERATURE TOOLS OFFSET BY UNCERTAINTY ABOUT THE
POTENTIAL DEVELOPMENT OF A TROPICAL CYCLONE ACROSS THE CARIBBEAN SEA AND ITS
EFFECTS ON THE PRECIPITATION OUTLOOK.

FORECASTER: MATT ROSENCRANS

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
OCTOBER 20

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:
20081006 - 19960918 - 20090916 - 19511005 - 19870917


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:
20081005 - 19960920 - 19680925 - 20090918 - 19900930


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 02 - 06 2016

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 04 - 10 2016

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

$$



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