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FXUS06 KWBC 201901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED AUGUST 20 2014

6-10 DAY OUTLOOK FOR AUG 26 - 30 2014

TODAYS MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE 500-HPA PATTERN FORECAST FOR
THE 6-10 DAY PERIOD. ALL MODELS AGREE ON POSITIVE HEIGHT ANOMALIES CENTERED
OVER THE NORTHERN PACIFIC, EXTENDING ACROSS THE ALEUTIANS SOUTHEASTWARD TO THE
WESTERN CONUS. THIS FEATURE IS MUCH WEAKER TODAY, HOWEVER, COMPARED TO
YESTERDAY`S OUTLOOK. A BROAD TROUGH IS FORECAST OVER CENTRAL NORTH AMERICA WITH
DOWNSTREAM RIDGING EXPECTED OVER FAR EASTERN CANADA. TODAYS MANUAL 500-HPA
HEIGHT BLEND FAVORS THE 0Z ECMWF ENSEMBLE, WHICH RECENTLY HAS HAD THE HIGHEST
SKILL OUT OF ALL AVAILABLE MODELS. THAT SAID, MODEL SKILL HAS BEEN GENERALLY
LOW (ANOMALY CORRELATIONS OF ~0.5) RECENTLY, NOT TOO UNEXPECTED GIVEN THE TIME
OF YEAR.

THE ANOMALOUS RIDGING OVER THE GULF OF ALASKA FAVORS ABOVE-NORMAL TEMPERATURES
IN ALASKA AND ALONG THE WEST COAST. FORECAST PROBABILITIES ARE LOWER COMPARED
TO YESTERDAY BECAUSE OF THE DEAMPLIFICATION OF THE FORECAST HEIGHT ANOMALIES.
MODELS ARE IN GOOD AGREEMENT ON ANOMALOUS TROUGHING OVER THE NORTHERN PLAINS
AND ROCKIES. ALL FORECAST TOOLS ARE IN REASONABLY GOOD AGREEMENT ON THE
FORECAST TEMPERATURE PATTERN ACROSS THE CENTRAL AND EASTERN CONUS, WITH A MEAN
FRONTAL POSITION FORECAST FROM THE GREAT LAKES TOWARD THE SOUTHWESTERN U.S.
NEAR-NORMAL TEMPERATURES ARE FAVORED FOR THE MID-ATLANTIC COAST DUE TO
ANOMALOUSLY HIGH SURFACE PRESSURE AND A PROLONGED PERIOD OF EASTERLY FLOW.

WHILE THE EXTRATROPICAL PATTERN IS GENERALLY WELL AGREED UPON, MORE FORECAST
UNCERTAINTY IS INTRODUCED BY WAY OF TROPICAL ACTIVITY IN BOTH TROPICAL BASINS.
A TROPICAL WAVE IN THE ATLANTIC IS FORECAST TO MOVE WEST-NORTHWESTWARD TOWARD
THE SOUTHEAST COAST, POSSIBLY DEVELOPING INTO A NAMED TROPICAL CYCLONE. THIS
ENHANCES ODDS OF ABOVE-MEDIAN PRECIPITATION FOR THE FLORIDA PENINSULA AND GULF
COAST. ODDS ARE THAT THIS SYSTEM WILL GET ENTRAINED IN THE WESTERLIES BEFORE IT
REACHES THE FAR WESTERN GULF, BUT NOT WELL EAST OF THE CONUS DUE TO GENERALLY
POSITIVE HEIGHT ANOMALIES OVER THE WESTERN ATLANTIC. IN THE EAST PACIFIC BASIN,
A TROPICAL DISTURBANCE IS EXPECTED TO MOVE NORTHWESTWARD OFF THE MEXICAN COAST,
WITH SOME ENSEMBLE MEMBERS (PARTICULARLY FROM THE GEFS AND CANADIAN ENSEMBLE)
SUGGESTING THAT MOISTURE FROM THIS SYSTEM WILL EFFECT THE SOUTHWESTERN CONUS.
THE ECMWF, HOWEVER, SUGGESTS THAT THE STORM STAYS WELL OFF THE NORTH AMERICAN
COAST AND HAS NO IMPACT OVER THE SOUTHWEST. SLIGHTLY ELEVATED PROBABILITIES FOR
ABOVE-MEDIAN PRECIPITATION ARE DEPICTED OVER PARTS OF SOUTHERN CALIFORNIA AND
ARIZONA TO ACCOUNT FOR THIS POSSIBILITY. IN LIGHT OF BOTH TROPICAL THREATS, THE
PRECIPITATION FORECAST IS QUITE UNCERTAIN, ESPECIALLY ACROSS THE SOUTHERN CONUS.

THE PRECIPITATION OUTLOOK ACROSS THE REMAINDER OF THE CONUS FOLLOWS FROM THE
FORECAST EXTRATROPICAL 500-HPA HEIGHT PATTERN ACROSS NORTH AMERICA. WITH A
TROUGH CENTERED NEAR 95W, ABOVE-MEDIAN (BELOW-MEDIAN) PRECIPITATION IS FAVORED
ALONG AND EAST OF THE AXIS (OVER THE PACIFIC NORTHWEST).

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


MODEL OF THE DAY: 0Z ECMWF ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
FAIRLY GOOD AGREEMENT AMONG THE MODELS AND TOOLS, OFFSET BY UNCERTAINTY DUE TO
EXPECTED TROPICAL STORM ACTIVITY THAT COULD IMPACT PARTS OF THE CONUS.

8-14 DAY OUTLOOK FOR AUG 28 - SEP 03, 2014

THE FORECAST CIRCULATION FOR WEEK-2 IS EXPECTED TO BE LESS AMPLIFIED, AND MORE
ZONAL, THAN DURING THE 6-10 DAY PERIOD. MOST DYNAMICAL AND STATISTICAL TOOLS
SUGGEST THAT THE AREA OF BELOW-NORMAL TEMPERATURES WILL EXPAND COMPARED TO THE
6-10 DAY PERIOD AS THE MEAN FRONTAL ZONE IS PUSHED FARTHER SOUTH AND EAST.
ALSO, 500-HPA HEIGHTS ARE EXPECTED TO BE NEAR OR BELOW THAT WHICH IS FORECAST
FOR THE 6-10 DAY PERIOD ACROSS THE ENTIRE CONUS, FAVORING A COOLER SOLUTION
RELATIVE TO THE PRECEDING PERIOD. THAT SAID, ENSEMBLE SPREAD IS VERY HIGH AND
MODEL SKILL HAS BEEN LOW OVER THE PAST SEVERAL WEEKS (500-HPA HEIGHT ANOMALY
CORRELATIONS OF ~0.3), SO PROBABILITIES ARE GENERALLY LOWER THAN IN THE 6-10
DAY PERIOD.

THE SAME UNCERTAINTIES WITH RESPECT TO PRECIPITATION LINGER FROM THE 6-10 DAY
PERIOD DUE TO TROPICAL CYCLONE ACTIVITY. OTHERWISE, AN EASTWARD PROGRESSION IS
DEPICTED IN THE PRECIPITATION OUTLOOK COMPARED TO THE PREVIOUS PERIOD.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 10% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 50% OF TODAY`S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 15% 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 REASONABLE AGREEMENT AMONG MODEL TOOLS, OFFSET BY A LOW-AMPLITUDE FORECAST
PATTERN, RECENTLY POOR MODEL PERFORMANCE, AND UNCERTAINTY WITH RESPECT TO
TROPICAL ACTIVITY.

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
AUGUST 21

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:
19800815 - 19610828 - 19640820 - 19870810 - 20080901


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:
19800816 - 19870809 - 19560829 - 20080829 - 19610830


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 26 - 30 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 28 - SEP 03, 2014

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