Prognostic Meteorological Discussion
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FXUS06 KWBC 252001
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 25 2017

6-10 DAY OUTLOOK FOR OCT 01 - 05 2017

TODAY`S ENSEMBLE MEAN SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT ON A FAIRLY
AMPLIFIED FLOW PATTERN OVER MUCH OF THE FORECAST DOMAIN. HOWEVER, SPREAD AND
UNCERTAINTY ARE HIGH AMONG THE COMPONENT ENSEMBLE MEMBERS OVER MUCH OF THE
COUNTRY, ESPECIALLY IN THE WESTERN CONUS. A FAIRLY STRONG ANOMALOUS RIDGE IS
FORECAST OVER THE NORTH PACIFIC AND ALEUTIANS, AND A TROUGH IS FORECAST FROM
EASTERN ALASKA TO THE NORTHWESTERN CONUS. A RIDGE IS ALSO EXPECTED TO BUILD
DOWNSTREAM OVER MUCH OF THE CENTRAL AND EASTERN CONUS. THE VARIOUS SPAGHETTI
MAPS (5640 AND 5820 METER LEVELS) DEPICT LARGE SPREAD AMONG THE COMPONENT
ENSEMBLE MEMBERS OVER MUCH OF THE COUNTRY. TODAY`S MANUAL 500-HPA HEIGHT BLEND
SLIGHTLY FAVORS THE 0Z ECMWF ENSEMBLE SOLUTION BASED PRIMARILY ON
CONSIDERATIONS OF RECENT SKILL.

THE RIDGE AND ABOVE NORMAL HEIGHT ANOMALIES OVER THE NORTH PACIFIC AND
ALEUTIANS INCREASES CHANCES FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF WESTERN
ALASKA. THE TROUGH AND BELOW NORMAL HEIGHT ANOMALIES OVER THE PACIFIC NORTHWEST
TILT THE ODDS TOWARDS BELOW NORMAL TEMPERATURES OVER WASHINGTON STATE AND
PORTIONS OF THE NORTHERN INTERMOUNTAIN REGION. THE ABOVE NORMAL HEIGHT
ANOMALIES OVER PART OF CALIFORNIA AND THE SOUTHWEST AND THE ABOVE NORMAL SSTS
ALONG THE WEST COAST ENHANCE PROBABILITIES OF ABOVE NORMAL TEMPERATURES OVER
THAT REGION. ABOVE NORMAL TEMPERATURES ARE STRONGLY FAVORED OVER THE NORTHERN
PLAINS, UPPER MISSISSIPPI VALLEY, GREAT LIKES AND NORTHEAST CONUS DUE TO A
RIDGE AND ABOVE NORMAL HEIGHT ANOMALIES OVER THE EAST-CENTRAL CONUS. ENHANCED
PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE INDICATED FOR COASTAL PARTS OF
THE SOUTHEAST AND FLORIDA, DUE TO PREDICTED EASTERLY FLOW.

THERE ARE LARGELY ENHANCED PROBABILITIES FOR ABOVE NORMAL PRECIPITATION FROM
THE PACIFIC NORTHWEST TO THE UPPER MISSISSIPPI VALLEY, INCLUDING MOST OF THE
ROCKIES AND GREAT PLAINS, IN ASSOCIATION WITH A TROUGH OVER THE NORTHWESTERN
CONUS, AND THE POTENTIAL ADVECTION OF TROPICAL MOISTURE INTO THE REGION. BELOW
NORMAL PRECIPITATION IS FAVORED FROM THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST
US TO THE NORTHEASTERN CONUS DUE TO EXPECTED RIDGING. THERE ARE INCREASED ODDS
FOR ABOVE NORMAL PRECIPITATION OVER FLORIDA DUE TO A PREDICTED COLD FRONT.
BELOW NORMAL SEA-LEVEL PRESSURE OVER THE BERING SEA AND THE NORTHWESTERN GULF
OF ALASKA FAVORS ABOVE NORMAL PRECIPITATION OVER WESTERN ALASKA.

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, 5% OF
TODAY`S OPERATIONAL 0Z GFS 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,
10% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 20% OF TODAY`S 0Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE MODELS AND TOOLS OVER MOST OF THE U.S.

8-14 DAY OUTLOOK FOR OCT 03 - 09 2017

COMPARED TO THE 6-10 DAY PERIOD, THE WEEK-2 CIRCULATION PATTERN IS SIMILAR BUT
MORE DEAMPLIFIED. THE WEEK-2 TEMPERATURE PATTERN IS WARMER OVERALL (ESPECIALLY
IN THE SOUTH, AND IN EASTERN ALASKA) COMPARED TO THE 6-10 DAY TEMPERATURE
PATTERN. THE PRECIPITATION OUTLOOK FOR THE WEEK-2 PERIOD IS EXPECTED TO BECOME
MORE EAST-WEST ORIENTED (ZONAL), COMPARED TO THE 6-10 DAY PRECIPITATION
OUTLOOK, WHICH IS SIGNIFICANTLY MORE NORTH-SOUTH ORIENTED (MERIDIONAL). THE
SOUTHERN PLAINS AND SOUTHERN ROCKIES ARE FORECAST TO TRANSITION FROM A
RELATIVELY WET 6-10 DAY PATTERN TO ONE THAT IS CLOSE TO NORMAL DURING WEEK-2.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 15% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 10% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 35% OF
TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO FAIRLY LARGE UNCERTAINTY IN TODAY`S ENSEMBLES.

FORECASTER: Y. FAN

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 19

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:
19820929 - 19520911 - 19830930 - 19571005 - 19860928


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:
19820929 - 19520911 - 19990904 - 19830930 - 19680919


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 01 - 05 2017

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 03 - 09 2017

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

$$



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