Prognostic Meteorological Discussion
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FXUS06 KWBC 151951
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 15 2014

6-10 DAY OUTLOOK FOR SEP 21 - 25 2014

THERE IS GOOD AGREEMENT AMONG TODAY`S ENSEMBLE MEAN FORECASTS OF 6-10 DAY
500-HPA HEIGHTS OVER NORTH AMERICA AND VICINITY. MODELS AGREE ON THE PREDICTION
OF A DEEP TROUGH OVER THE EASTERN NORTH PACIFIC, SOUTH OF THE ALEUTIAN ISLANDS.
 A STRONG RIDGE IS PREDICTED OVER THE WEST COAST OF NORTH AMERICA. DOWNSTREAM
FROM THESE FEATURES, MODELS PREDICT A TROUGH OVER THE EASTERN CONUS. MOST
ENSEMBLE MEANS PREDICT HEIGHTS TO BE ONLY SLIGHTLY BELOW AVERAGE IN THE TROUGH
OVER THE EASTERN CONUS, HOWEVER, THERE IS CONSIDERABLE SPREAD AMONG THE
INDIVIDUAL ENSEMBLE MEMBERS ON ITS STRENGTH. A STRONGER EASTERN TROUGH WILL
FAVOR COOLER TEMPERATURES THROUGHOUT THE EAST THAN INDICATED BY THE MEAN
SURFACE TEMPERATURE FORECASTS FROM THE MODELS, LEADING TO GREATER UNCERTAINTY
IN THE FORECAST FOR THE EASTERN CONUS. CONFIDENCE IS HIGH IN THE FORECAST FOR
THE WEST.

THE STRONG RIDGE FORECAST OVER THE WESTERN CONUS FAVORS ABOVE-NORMAL
TEMPERATURES WITH A CONSIDERABLE DEGREE OF CONFIDENCE. TEMPERATURES OVER THE
EASTERN CONUS ARE MUCH LESS CERTAIN DUE TO UNCERTAINTIES IN THE STRENGTH OF THE
EXPECTED NEARBY TROUGH. PREDICTION FROM MOST MODELS SUGGEST THAT THE WARM
TEMPERATURES ASSOCIATED WITH THE WESTERN RIDGE WILL EXTEND WELL INTO CANADA,
RESULTING IN RELATIVE MILD AIR BEING DRAWN DOWN IN THE NORTHERLY FLOW BEHIND
THE TROUGH AXIS.  THUS, NEAR NORMAL TEMPERATURES ARE FAVORED THROUGHOUT MUCH OF
THE EAST. THE ODDS OF ABOVE-NORMAL TEMPERATURES ARE ELEVATED ALONG THE GULF OF
MEXICO DUE TO WARM TEMPERATURES FORECAST BY MOST MODELS, AND ABOVE NORMAL SEA
SURFACE TEMPERATURES IN THE REGION.

THE TROUGH OVER THE EASTERN CONUS ENHANCES PROBABILITIES FOR ABOVE-MEDIAN
PRECIPITATION AMOUNTS OVER MUCH OF THE EASTERN CONUS. THE GEFS ENSEMBLE
SUGGESTS THE MAIN FOCUS OF THE PRECIPITATION WILL BE WEST OF THE APPALACHIANS,
LEADING TO LESSER PRECIPITATION AMOUNTS IN PARTS OF THE EAST COAST, WHERE
NEAR-MEDIAN AMOUNTS ARE THE MOST LIKELY CATEGORY. MEAN SEA LEVEL PRESSURE
PREDICTIONS FROM THE MODELS SUGGEST EASTERLY FLOW OVER THE SOUTHEAST AND GULF
COAST STATES, WHICH COMBINED WITH WARM SSTS IN THE GULF OF MEXICO ELEVATE THE
CHANCES FOR ABOVE-MEDIAN PRECIPITATION FOR THE SOUTHEAST AND TEXAS. THE
POSSIBILITY OF SOME RESIDUAL MOISTURE FROM TROPICAL STORM ODILE CURRENTLY OVER
SOUTHERN BAJA CALIFORNIA, ELEVATE CHANCES FOR ABOVE-MEDIAN PRECIPITATION FOR
PARTS OF THE SOUTHERN ROCKIES AND THE SOUTHERN GREAT PLAINS. THE WESTERN RIDGE
ENHANCES CHANCES FOR BELOW-MEDIAN PRECIPITATION FROM THE PACIFIC NORTHWEST TO
THE UPPER GREAT LAKES. SOUTHWESTERLY UPPER-LEVEL FLOW INCREASE CHANCES OF
ABOVE-MEDIAN PRECIPITATION FOR SOUTHEASTERN ALASKA. THE GEFS ENSEMBLE MEAN
PRECIPITATION AMOUNTS FAVOR BELOW-MEDIAN PRECIPITATION IN SOUTHWESTERN ALASKA
WITH ABOVE-MEDIAN PRECIPITATION FAVORED ALONG THE NORTH SLOPE.

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


MODEL OF THE DAY: TODAY`S 0Z ECMWF ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE MODEL HEIGHT FORECASTS, AND A STRONG FORECAST ANOMALY
PATTERN OVER WESTERN NORTH AMERICA.

8-14 DAY OUTLOOK FOR SEP 23 - 29 2014

THE ENSEMBLE MEAN SOLUTIONS FOR THE 500-HPA HEIGHTS FOR THE 8-14 DAY PERIOD ARE
QUITE SIMILAR TO THE 6-10 DAY MEAN. THE CONTINUED PRESENCE OF A TROUGH OVER THE
EASTERN CONUS FOR THE 7-DAY PERIOD SUGGEST INCREASED CHANCES OF BELOW-NORMAL
TEMPERATURES OVER PARTS OF THE NORTH-CENTRAL AND NORTHEASTERN CONUS. ELSEWHERE,
TEMPERATURE ANOMALIES FOR THE 8-14 DAY PERIOD ARE EXPECTED TO BE SIMILAR TO
THOSE IN THE 6-10 DAY PERIOD.

THE PRECIPITATION FORECAST FOR THE 8-14 DAY PERIOD IS SUBSTANTIALLY DRIER THAN
THE 6-10 DAY FOR PARTS OF THE GREAT PLAINS TO THE OHIO VALLEY, SINCE MOST OF
THE PRECIPITATION IN THE 6-10 DAY IS EXPECTED TO BE CLEAR OF THE AREA BY DAY-8.
OTHERWISE THE OUTLOOK FOR 8-14 DAYS IS QUITE SIMILAR TO THE 6-10 DAY PERIOD.
THE POSSIBILITY OF CONTINUED MOISTURE SURGES FROM TROPICAL STORM ACTIVITY IN
THE EASTERN PACIFIC OFF THE WESTERN COAST OF MEXICO WILL HAVE TO BE WATCHED
CLOSELY. THE GEFS SLIGHTLY FAVORS ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE
SOUTHERN ROCKIES, ALTHOUGH AS A WHOLE.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 30% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON
DAY 11, AND 30% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO GOOD AGREEMENT ON THE POSITION OF LONGWAVE FEATURES.

FORECASTER: DAVE UNGER

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 18

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:
19550909 - 19740912 - 20070910 - 19730915 - 20080915


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:
19550908 - 19740910 - 19840928 - 19950913 - 20080913


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 21 - 25 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 23 - 29 2014

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

                           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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