Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2
329
FXUS06 KWBC 221947
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON MAY 22 2017

6-10 DAY OUTLOOK FOR MAY 28 - JUN 01, 2017

RECENT ENSEMBLE MEAN SOLUTIONS OF THE NCEP GEFS, ECMWF AND CANADIAN MODELS ARE
IN GOOD AGREEMENT ON THE LARGE SCALE CIRCULATION PATTERN FORECAST FOR THE 6-10
DAY PERIOD. MODELS FORECAST A RELATIVE TROUGH OVER THE ALEUTIAN ISLANDS, A
RIDGE  EXTENDING FROM EASTERN ALASKA SOUTHWARD ALONG THE PACIFIC COAST OF
CANADA INTO THE WESTERN CONUS, AND A TROUGH OVER EASTERN NORTH AMERICA. HIGH
RESOLUTION MODEL RUNS OF THE NCEP GFS AND ECMWF PREDICT SIMILAR, THOUGH
SLIGHTLY MORE AMPLIFIED, FLOW PATTERNS. TODAY`S MANUAL BLEND OF THE 500-HPA
HEIGHT FIELD INDICATES ABOVE NORMAL HEIGHT ANOMALIES OVER ALASKA, THE WESTERN
CONUS, AND ALONG THE GULF AND ATLANTIC COASTS.

ABOVE NORMAL TEMPERATURES ARE FORECAST FOR MUCH OF THE WESTERN U.S., UNDER
ABOVE NORMAL HEIGHTS, WITH GREATER PROBABILITIES FOR REGIONS WEST OF THE ROCKY
MOUNTAINS AND FOR THE PACIFIC NORTHWEST. WITH A PREDICTED TROUGH AND NORTHERLY
MID-LEVEL ATMOSPHERIC FLOW OVER THE CENTRAL U.S., BELOW NORMAL TEMPERATURES ARE
MOST LIKELY FROM JUST EAST OF THE ROCKY MOUNTAINS, INCLUDING THE CENTRAL AND
SOUTHERN PLAINS, TO THE MISSISSIPPI RIVER. ABOVE NORMAL TEMPERATURES ARE MOST
LIKELY FOR THE GULF COAST, WHERE HEIGHTS ARE PREDICTED TO BE NEAR TO ABOVE
NORMAL, AND FOR MUCH OF THE EASTERN U.S., WHERE ATMOSPHERIC FLOW IS ANOMALOUSLY
FROM THE SOUTH. ABOVE NORMAL TEMPERATURES ARE PREDICTED TO BE MOST LIKELY FOR
WESTERN AND NORTHERN PARTS OF ALASKA, WHILE BELOW NORMAL TEMPERATURES ARE MORE
LIKELY FOR SOME INTERIOR AND SOUTHERN PARTS OF THE STATE, FOLLOWING REFORECAST
CALIBRATIONS OF THE ECMWF AND GEFS ENSEMBLE PREDICTION SYSTEMS.

TROUGHING TO THE WEST OF ALASKA LEADS TO A FORECAST OF ABOVE MEDIAN
PRECIPITATION FOR WESTERN REGIONS OF THE STATE, WHILE BELOW MEDIAN
PRECIPITATION IS MORE LIKELY FOR EASTERN REGIONS OF THE STATE INCLUDING THE
ALASKA PANHANDLE, UNDER THE PREDICTED MID-LEVEL RIDGE. ENHANCED PROBABILITIES
OF BELOW MEDIAN PRECIPITATION EXTEND SOUTHWARD INTO THE PACIFIC NORTHWEST AND
THE NORTHERN PLAINS. ABOVE MEDIAN PRECIPITATION IS MOST LIKELY FOR A LARGE AREA
OF THE CONUS FROM JUST EAST OF THE SOUTHERN AND CENTRAL ROCKIES ACROSS THE
SOUTHERN PLAINS INTO MOST OF THE CONUS TO THE EAST OF THE MISSISSIPPI VALLEY.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 10% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 50%
OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN 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 THE MODEL SOLUTIONS AND GOOD AGREEMENT AMONG THE
TEMPERATURE AND PRECIPITATION TOOLS.

8-14 DAY OUTLOOK FOR MAY 30 - JUN 05, 2017

ENSEMBLE MEAN FORECASTS FROM THE NCEP GEFS, ECMWF AND CANADIAN MODELS GENERALLY
PERSIST THE PATTERN FROM THE 6-10 DAY PERIOD INTO THE 8-14 DAY PERIOD. RELATIVE
TROUGHING CONTINUES TO BE FORECAST TO THE WEST OF ALASKA, WHILE RIDGING
CONTINUES TO BE FORECAST FROM EASTERN ALASKA SOUTHWARD INTO THE PACIFIC
NORTHWEST. ENSEMBLE SPREAD IS INCREASING AT THE LONGER LEAD TIMES OF THE 8-14
DAY PERIOD FORECAST, SUCH THAT MEAN ANOMALIES ARE MUCH LESS AMPLIFIED THAN IN
THE 6-10 DAY PERIOD FORECAST. A SHORTWAVE TROUGH IS PREDICTED NEAR THE PACIFIC
COAST OF CALIFORNIA IN THE 8-14 DAY PERIOD, WHILE THE TROUGH PREDICTED OVER THE
EASTERN CONUS IS MUCH LESS AMPLIFIED. THE TEMPERATURE AND PRECIPITATION
PATTERNS FORECAST FOR THE 8-14 DAY PERIOD ARE SOMEWHAT SIMILAR TO THE 6-10 DAY
PERIOD FORECAST, WITH SOME SLIGHT CHANGES RESULTING FROM CHANGES IN THE
CIRCULATION FORECAST.

ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES CONTINUE TO BE FORECAST FOR
WESTERN AND NORTHERN REGIONS OF ALASKA, AS WELL AS THE ALASKA PANHANDLE. BELOW
NORMAL TEMPERATURES CONTINUE TO BE PREDICTED FOR SOUTHEASTERN REGIONS OF THE
STATE BY THE ECMWF AND GEFS ENSEMBLE PREDICTION SYSTEMS. ENHANCED PROBABILITIES
OF ABOVE NORMAL TEMPERATURES ARE FORECAST DURING THE 8-14 DAY PERIOD FOR MUCH
OF THE WEST, THOUGH NEAR NORMAL TEMPERATURES ARE NOW EXPECTED TO BE MORE LIKELY
FOR MUCH OF THE CALIFORNIA COAST, WHERE A SHORTWAVE TROUGH IS PREDICTED. BELOW
NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY FOR MUCH OF THE CENTRAL AND
SOUTHERN PLAINS, WITH SOMEWHAT WEAKER PROBABILITIES DUE TO INCREASING ENSEMBLE
SPREAD, WHILE ABOVE NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY FOR THE GULF
AND ATLANTIC COASTS.

ABOVE MEDIAN PRECIPITATION IS MOST LIKELY ACROSS A SIMILAR LARGE AREA OF THE
CONUS TO THE EAST OF THE ROCKY MOUNTAINS. PROBABILITIES OF ABOVE MEDIAN
PRECIPITATION ARE GREATER IN THE 8-14 DAY PERIOD FOR PARTS OF THE GREAT BASIN
AND NORTHERN ROCKIES EAST OF A PREDICTED SHORTWAVE TROUGH. ABOVE MEDIAN
PRECIPITATION CONTINUES TO BE MOST LIKELY FOR NORTHERN AND WESTERN REGIONS OF
ALASKA, AS IN THE 6-10 DAY PERIOD FORECAST, WHILE BELOW MEDIAN PRECIPITATION IS
MOST LIKELY FOR SOUTHEASTERN PARTS OF THE STATE.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 10% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% OF TODAY`S 6Z 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 SOME DISAGREEMENT BETWEEN MODELS AND AMONG TEMPERATURE AND PRECIPITATION
TOOLS.

FORECASTER: DAN C

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
JUNE 15

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:
20070530 - 19750528 - 19790511 - 19950525 - 19850514


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:
20070530 - 19750527 - 19910501 - 19950525 - 19700601


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 28 - JUN 01, 2017

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 30 - JUN 05, 2017

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

                           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.