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FXUS06 KWBC 231901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE SEPTEMBER 23 2014

6-10 DAY OUTLOOK FOR SEP 29 - OCT 03, 2014

TODAY`S MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON THE FORECAST CIRCULATION
FOR THE 6-10 DAY PERIOD. THE DOMINANT FEATURE ON THE OFFICIAL 500-HPA HEIGHT
MANUAL BLEND CONTINUES TO BE THE HIGH-AMPLITUDE, COHERENT WAVE PATTERN CENTERED
ON THE NORTH ATLANTIC, WITH A TROUGH SOUTH OF GREENLAND, AND RIDGES UPSTREAM
AND DOWNSTREAM OVER EASTERN NORTH AMERICA AND NORTHWESTERN EUROPE,
RESPECTIVELY. MODEL SOLUTIONS HAVE TRENDED A BIT TOWARD THE ECMWF SOLUTION FROM
YESTERDAY, WITH A DEEPER TROUGH CENTERED OVER THE NORTHERN ROCKIES. HOWEVER,
POSITIVE HEIGHT ANOMALIES ARE FORECAST TO EXTEND FROM THE NORTHEASTERN PACIFIC
TOWARD NORTHWESTERN NORTH AMERICA, SOMETHING THE GFS AND ITS ENSEMBLE MEAN WERE
HINTING AT YESTERDAY.

THE TOOLS DERIVED FROM THE GFS AND ECMWF FORECAST SYSTEMS ARE IN STILL IN GOOD
AGREEMENT AT THE SURFACE. GIVEN THE LARGE POSITIVE HEIGHT ANOMALY FORECAST JUST
NORTH OF THE GREAT LAKES, ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE
CENTRAL AND EASTERN CONUS, THOUGH SOME EASTWARD PROGRESSION IS FORECAST
COMPARED TO YESTERDAY. SOME ADJUSTMENTS WERE MADE TO REIGN IN EXCESSIVELY HIGH
PROBABILITIES IN THE FIRST GUESS AUTOMATED FORECAST. THE ADJUSTMENTS WERE MADE
ACROSS NORTHERN NEW ENGLAND, WHERE THERE IS SOME POSSIBILITY OF A COLD FRONT
BRINGING IN A CANADIAN AIR MASS LATER IN THE PERIOD, AS INDICATED BY
TELECONNECTIONS UPON THE INTENSE UPPER-LEVEL TROUGH FORECAST IN THE NORTH
ATLANTIC. ADDITIONALLY, PROBABILITIES WERE MODIFIED SOMEWHAT ACROSS THE
SOUTHEAST, WHERE ANOMALOUSLY WET CONDITIONS CONTINUE TO BE FAVORED. FOR THE
WESTERN THIRD OF THE CONUS, UPPER-LEVEL TROUGHING FAVORS BELOW-NORMAL
TEMPERATURES. CONFIDENCE IS HIGHER IN THIS REGION THAN IT WAS YESTERDAY, DUE TO
BETTER AGREEMENT AMONG FORECAST TOOLS. A TENDENCY TOWARD HIGHER 500-HPA HEIGHTS
AND WARMER-THAN-NORMAL SSTS FAVORS ABOVE-NORMAL TEMPERATURES ALONG THE
IMMEDIATE CALIFORNIA COAST.

THE HIGH-AMPLITUDE RIDGE FORECAST OVER EASTERN NORTH AMERICA LEADS TO A FAIRLY
HIGH-CONFIDENCE PRECIPITATION OUTLOOK ACROSS THE NORTHERN TIER OF THE CONUS.
SURFACE HIGH PRESSURE AND ANOMALOUS MID-LEVEL NORTHERLIES FAVOR BELOW-MEDIAN
PRECIPITATION ACROSS PARTS OF THE NORTHEASTERN CONUS. ANOMALOUS SOUTHEASTERLY
FLOW AT LOW-TO-MID LEVELS FAVORS ABOVE-MEDIAN PRECIPITATION FOR MUCH OF THE
ROCKIES, PLAINS, AND MIDWEST. PARTS OF THE SOUTHEAST ARE EXPECTED TO RECEIVE
ABOVE-MEDIAN RAINFALL DUE TO TROPICAL MOISTURE INTERACTING WITH THE REMNANTS OF
A COLD FRONT.

ANOMALOUS UPPER-LEVEL RIDGING FAVORS DRIER-THAN-NORMAL CONDITIONS ACROSS PARTS
OF INTERIOR ALASKA, WHILE ANOMALOUS MID-LEVEL SOUTHERLIES ARE EXPECTED TO
INCREASE ODDS OF ABOVE-MEDIAN PRECIPITATION ACROSS PARTS OF SOUTHERN ALASKA AND
THE PANHANDLE. A COMBINATION OF WARM SSTS SOUTH OF ALASKA AND ABOVE-NORMAL
500-HPA HEIGHTS FARTHER NORTH LEAD TO ENHANCED PROBABILITIES FOR ABOVE-NORMAL
TEMPERATURES ACROSS MOST OF THE STATE.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 15% OF TODAY`S OPERATIONAL 6Z GFS
CENTERED ON DAY 8, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 20%
OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, 30% 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: 0Z ECMWF ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG TOOLS OVER THE CONUS, OFFSET SLIGHTLY BY MODEL
DISAGREEMENT AT UPPER-LEVELS OVER PARTS OF THE NORTH PACIFIC THAT COULD IMPACT
DOWNSTREAM SURFACE CLIMATE.

8-14 DAY OUTLOOK FOR OCT 01 - 07 2014

TODAY`S WEEK-2 500-HPA HEIGHT MANUAL BLEND SHOWS SOME EASTWARD PROPAGATION AND
DEAMPLIFICATION COMPARED TO THE 6-10 DAY PERIOD. ENSEMBLE SPREAD AND RUN-TO-RUN
VARIABILITY IS QUITE LOW FOR THE GFS, BUT HIGHER FOR THE ECMWF. THE ECMWF
FAVORS MORE ANOMALOUS TROUGHING ACROSS THE NORTHWESTERN CONUS THAN DO THE GFS
AND CANADIAN ENSEMBLE MEANS. THE GFS AND ECMWF SYSTEMS ARE GIVEN EQUAL
WEIGHTING IN THE MANUAL BLEND FOR THIS PERIOD, IN PART TO KEEP CONTINUITY WITH
YESTERDAY, WHILE ALSO ACCOUNTING FOR THE CONSISTENCY AND LOW ENSEMBLE SPREAD
FOUND IN THE GFS SOLUTIONS. THE 06Z GFS ENSEMBLE MEAN REVEALS A
WELL-TELECONNECTED PATTERN AND EXHIBITS A HIGHER ANOMALY CORRELATION WITH THE
COMPOSITE HEIGHT ANALOG DERIVED FROM ITS FORECAST.

AGAIN, AT THE SURFACE THERE IS FAIRLY LITTLE DIFFERENCE, THOUGH THE ECMWF IS
GENERALLY SHIFTED WEST COMPARED TO THE GFS-DERIVED TOOLS. THIS OUTLOOK
REPRESENTS A COMPROMISE BETWEEN THE TWO, WITH A SLIGHT SHIFT TOWARD THE GFS
SOLUTION. THE ONLY APPRECIABLE CHANGE IN THE WEEK-2 OUTLOOK COMPARED WITH THE
6-10 DAY OUTLOOK IS AN EASTWARD SHIFT OF PROBABILITIES, REFLECTING THE
GENERALLY PROGRESSIVE NATURE OF THE FORECAST CIRCULATION.

ALASKA IS GENERALLY EXPECTED TO REMAIN ACTIVE AND WARMER-THAN-NORMAL AS
ANOMALOUS SOUTHERLY FLOW IS EXPECTED TO DOMINATE DURING MUCH OF THE PERIOD.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S OPERATIONAL 0Z
GFS CENTERED ON DAY 11, 10% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 11,
10% OF TODAY`S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY`S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 45% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 10% 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 LOWER ENSEMBLE SPREAD AND BETTER RUN-TO-RUN CONTINUITY OFFSET BY SOME FAIRLY
LARGE DIFFERENCES BETWEEN THE GFS AND ECMWF FORECAST CIRCULATIONS.

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
OCTOBER 16

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:
19690910 - 19651002 - 20030904 - 19840916 - 19630930


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:
19690910 - 19870930 - 19530910 - 19630907 - 19801006


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 29 - OCT 03, 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 01 - 07 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       N    B     NEVADA      A    B
W MONTANA   N    B     E MONTANA   N    N     WYOMING     B    N
UTAH        B    N     ARIZONA     N    N     COLORADO    B    A
NEW MEXICO  B    N     N DAKOTA    N    A     S DAKOTA    N    A
NEBRASKA    B    A     KANSAS      N    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     N    A
MINNESOTA   N    A     IOWA        N    A     MISSOURI    A    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   A    A
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    N
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    A
AK ALEUTIAN A    A     AK WESTERN  A    N     AK INT BSN  A    N
AK S INT    A    N     AK SO COAST A    A     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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