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FXUS06 KWBC 221908
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 22 2014

6-10 DAY OUTLOOK FOR SEP 28 - OCT 02, 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 IS 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 DIVERGE, HOWEVER, FARTHER UPSTREAM OVER THE NORTHEASTERN PACIFIC AND
WESTERN NORTH AMERICA. THE GFS AND ITS ENSEMBLE MEAN FAVOR ABOVE-NORMAL HEIGHTS
BUILDING NEAR AND JUST OFF THE WEST COAST, WHILE THE ECMWF AND ITS ENSEMBLE
MEAN SUGGEST NEGATIVE HEIGHT ANOMALIES EXTENDING FROM THE NORTHEASTERN PACIFIC
SOUTHEASTWARD TO THE INTERMOUNTAIN WEST. TELECONNECTIONS UPON THE LARGEST
FORECAST ANOMALY CENTERS SLIGHTLY FAVOR THE ECWMF SOLUTION. ALSO, THE ECMWF HAS
DISPLAYED BETTER CONTINUITY FROM RUN TO RUN ON THIS ISSUE, THOUGH ENSEMBLE
SPREAD IS HIGH IN BOTH SYSTEMS. THEREFORE, THE ECMWF IS GIVEN HIGHER WEIGHTING
THAN THE GFS IN TODAY`S MANUAL BLEND.

THESE DIFFERENCES BECOME SOMEWHAT LESS INTERESTING AT THE SURFACE, WHERE TOOLS
DERIVED FROM BOTH SYSTEMS REMAIN IN GOOD AGREEMENT. GIVEN THE IMPRESSIVE
POSITIVE HEIGHT ANOMALY FORECAST JUST NORTH OF THE GREAT LAKES, ABOVE-NORMAL
TEMPERATURES ARE FAVORED FOR MOST OF THE CENTRAL AND EASTERN CONUS. SOME
ADJUSTMENTS WERE MADE TO REIGN IN EXCESSIVELY HIGH PROBABILITIES ACROSS 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
ARE FAVORED. FOR THE WESTERN THIRD OF THE CONUS, UPPER-LEVEL TROUGHING FAVORS
BELOW-NORMAL TEMPERATURES, BUT NOT EXCEPTIONALLY SO, ACROSS PARTS OF THE
SOUTHWEST AND INTERMOUNTAIN WEST. NEAR-NORMAL TEMPERATURES ARE MOST LIKELY
ACROSS THE PACIFIC NORTHWEST. 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 FROM THE GREAT LAKES EASTWARD. ANOMALOUS SOUTHEASTERLY FLOW AT
LOW-TO-MID LEVELS FAVORS ABOVE-MEDIAN PRECIPITATION FOR MUCH OF THE ROCKIES,
HIGH PLAINS, AND SOUTHWEST. 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 MOST
OF ALASKA, WHILE TROUGHING IN THE GULF OF ALASKA IS EXPECTED TO KEEP THE
ALASKAN PANHANDLE ACTIVE. 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 10% OF TODAY`S OPERATIONAL 0Z GFS
CENTERED ON DAY 8, 10% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 20% OF
TODAY`S 0Z 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 10% 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 SEP 30 - OCT 06, 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 (ESPECIALLY WITH THE GFS) IS PROBLEMATIC FOR THIS PERIOD. THE ECMWF
FAVORS MORE ANOMALOUS TROUGHING ACROSS THE WESTERN CONUS THAN DO THE GFS AND
CANADIAN ENSEMBLE MEANS. AS IN THE PRECEDING PERIOD, TELECONNECTIONS UPON THE
LARGEST ANOMALY CENTERS OVER NORTHERN EUROPE AND NORTHEASTERN ASIA TEND TO
SUPPORT THE ECWMF, THOUGH NOT OVERWHELMINGLY.

AGAIN, AT THE SURFACE THERE IS FAIRLY LITTLE DIFFERENCE, THOUGH THE ECMWF
SUPPORTS A LARGER AREA FAVORING BELOW-NORMAL TEMPERATURES ACROSS THE WESTERN
U.S. THIS OUTLOOK REPRESENTS A COMPROMISE BETWEEN THE TWO, WITH A SLIGHT SHIFT
TOWARD THE ECMWF 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 BECOME MORE ACTIVE COMPARED TO THE 6-10 DAY
PERIOD, AS ANOMALOUS SOUTHERLY FLOW IS EXPECTED TO DOMINATE, ESPECIALLY LATE IN
THE PERIOD.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 30% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 50% 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: BELOW AVERAGE, 2 OUT OF 5, DUE
TO HIGH SPREAD AMONG TODAY`S ENSEMBLE MEMBERS AND CONTINUED DISAGREEMENT
BETWEEN THE ECMWF AND GFS ENSEMBLE MEANS OVER THE WESTERN CONUS.

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 - 19870930 - 19840916 - 19790915


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:
19690909 - 19630906 - 19870930 - 19840916 - 19790915


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 28 - OCT 02, 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 30 - OCT 06, 2014

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    N     OREGON      N    B     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       B    N     NEVADA      N    B
W MONTANA   N    A     E MONTANA   N    A     WYOMING     N    A
UTAH        B    B     ARIZONA     B    B     COLORADO    N    A
NEW MEXICO  B    A     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    N
VERMONT     A    B     NEW HAMP    A    B     MAINE       A    B
MASS        A    N     CONN        A    N     RHODE IS    A    N
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    A
MARYLAND    A    N     DELAWARE    A    N     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    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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