Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS06 KWBC 311930
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI JULY 31 2015

6-10 DAY OUTLOOK FOR AUG 06 - 10 2015

TODAY`S ENSEMBLE MEANS ARE IN GOOD AGREEMENT ON THE FORECAST 500-HPA MEAN
CIRCULATION PATTERN OVER NORTH AMERICA AND VICINITY FOR THE 6-10 DAY PERIOD.
THE FORECAST HEIGHT PATTERN REMAINS SIMILAR TO YESTERDAY`S, BUT WITH SOME
EASTWARD PROGRESSION OVER WESTERN NORTH AMERICA. THIS, COMBINED WITH WITH
LITTLE MOVEMENT OF FORECAST ANOMALIES OVER EASTERN NORTH AMERICA, RESULTS IN A
SLIGHT SHORTENING OF THE WAVELENGTHS COMPARED TO YESTERDAY`S 500-HPA HEIGHT
BLEND.

BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE NORTHERN CONUS UNDER
BELOW-NORMAL 500-HPA HEIGHTS. FORECAST TOOLS HAVE COME INTO BETTER AGREEMENT
WITH RESPECT TO TEMPERATURES ACROSS THE INTERIOR WEST, WITH BELOW-NORMAL
TEMPERATURES NOW BEING SLIGHTLY FAVORED UNDER AN ANOMALOUS FORECAST TROUGH.
PROBABILITIES OF BELOW-NORMAL TEMPERATURES OVER THE NORTHEASTERN CONUS ARE
INCREASED OVER YESTERDAY`S OUTLOOK DUE TO EXCELLENT AGREEMENT AMONG ALL
TEMPERATURE TOOLS. THERE IS SOME INCREASED UNCERTAINTY OVER THE FRONT RANGE,
WHERE LAST NIGHT`S DETERMINISTIC RUNS OF THE GFS AND ECMWF INDICATE SLIGHTLY
ABOVE-NORMAL HEIGHTS IN ADVANCE OF AN AMPLIFYING SHORTWAVE OVER THE NORTHWEST.
THEIR RESPECTIVE ENSEMBLE MEANS REVEAL LESS OVERALL AMPLIFICATION, BUT THE
POSSIBILITY OF A WARMER SOLUTION ACROSS THE FRONT RANGE WAS NONETHELESS
ACCOUNTED FOR.

THE PRECIPITATION OUTLOOK IS SIMILAR TO YESTERDAY`S WITH ONLY MINOR CHANGES
MADE TO ACCOUNT FOR THE UPDATED GUIDANCE REGARDING THE POSITION OF THE MEAN
FRONTAL BOUNDARY. THOSE CHANGES ARE CONSISTENT WITH THE PREVIOUSLY EXPECTED
EVOLUTION FROM THE 6-10 DAY PERIOD TO WEEK-2.

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, 15%
OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 25% OF TODAY`S 0Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 8, 15% 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, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG VARIOUS TOOLS, OFFSET SLIGHTLY BY UNCERTAINTY OVER THE
FRONT RANGE.

8-14 DAY OUTLOOK FOR AUG 08 - 14 2015

THE FORECAST CIRCULATION FOR WEEK-2 REMAINS DEAMPLIFIED COMPARED TO THE 6-10
DAY PERIOD, THOUGH THE MAJOR FEATURES REMAIN INTACT. THE LARGEST CHANGES ARE
UPSTREAM OVER THE NORTH PACIFIC, WHERE MORE UNIFORM NEGATIVE HEIGHT ANOMALIES
ARE FORECAST COMPARED TO THE PAST COUPLE OF DAYS. THE MOST RECENT FEW RUNS OF
THE DETERMINISTIC GFS SHOW A DEEP, CONSOLIDATED TROUGH OVER THE NORTH PACIFIC.
THIS LEADS TO A WARMER SOLUTION, AT LEAST BRIEFLY, OVER THE WEST-CENTRAL CONUS
WHERE FORECAST 500-HPA HEIGHTS ARE SLIGHTLY ABOVE NORMAL. THIS LEADS TO
NEAR-NORMAL TEMPERATURES BEING FAVORED OVER A FAIRLY LARGE SWATH OF THE
NORTH-CENTRAL CONUS. IF THE ENSEMBLE MEANS CONTINUE THE TREND SEEN IN THE
RECENT DETERMINISTIC RUNS, A RETROGRESSION OF THE LONG-WAVE PATTERN MIGHT BE
EXPECTED LATE IN WEEK-2 AND BEYOND. THIS IS CONSISTENT WITH COUPLED CFS AND
ECMWF EXTENDED GUIDANCE, WHICH SHIFTS THE BEST ODDS OF BELOW(ABOVE)-NORMAL
TEMPERATURES TO THE CENTRAL PLAINS (PACIFIC NORTHWEST) FOR WEEKS 3 AND 4. THIS
IS ALSO CONSISTENT WITH THE LOW-FREQUENCY ENSO SIGNAL.

THE PRECIPITATION OUTLOOK REMAINS VERY SIMILAR TO THAT ISSUED YESTERDAY. ODDS
OF BELOW-MEDIAN PRECIPITATION ARE NOW HIGHER OVER THE OHIO VALLEY, SINCE THE
FORECAST ANOMALY PATTERN RETAINS A HIGHER AMPLITUDE TODAY. THIS IS DUE IN PART
TO BETTER AGREEMENT AMONG THE VARIOUS DYNAMICAL MODELS.

ANALOGS BASED ON TODAY`S 500-HPA HEIGHT BLEND CONTINUE TO FAVOR A WARM ENSO
STATE, HIGHLIGHTING THE CONSISTENCY OF THE FORECAST WITH THE ONGOING
LOW-FREQUENCY STATE. SEE WEDNESDAY`S DISCUSSION IN THE ARCHIVES FOR A MORE
DETAILED DISCUSSION OF THE USEFULNESS OF ENSO AS A WEEK-2 PREDICTOR OVER THE
NEXT FEW MONTHS
(HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ARCHIVES/SHORT_RANGE/2015/07/29/PMDMRD.20
150729.TXT).

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 0Z GFS CENTERED ON DAY 11, 10% OF TODAY`S
OPERATIONAL 6Z GFS 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: AVERAGE, 3 OUT OF 5, DUE TO
RELATIVELY GOOD AGREEMENT AMONG THE ENSEMBLE MEANS OFFSET BY A FORECAST
LOW-AMPLITUDE FLOW AND A POTENTIAL PATTERN CHANGE OVER THE NORTH PACIFIC.

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 20

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:
19840712 - 20020729 - 19810804 - 19620713 - 19730812


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:
19840712 - 19960809 - 20020730 - 19810803 - 19730811


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 06 - 10 2015

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 08 - 14 2015

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

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.