Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2

000
FXUS06 KWBC 191924
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE AUGUST 19 2014

6-10 DAY OUTLOOK FOR AUG 25 - 29 2014

TODAYS MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE 500-HPA PATTERN FORECAST FOR
THE 6-10 DAY PERIOD. ALL MODELS AGREE ON HIGH AMPLITUDE RIDGING IN THE GULF OF
ALASKA AND NEAR THE WESTERN COAST OF THE CONUS, A BROAD TROUGH OVER MUCH OF THE
NORTHERN U.S., AND A RIDGE IN THE SOUTHEASTERN CONUS. SPAGHETTI CHARTS INDICATE
A GOOD DEAL OF UNCERTAINTY REGARDING THE 500-HPA HEIGHT PATTERN OVER THE
NORTHEAST AND INTO THE WESTERN ATLANTIC. SOME MEMBERS FROM THE LATEST GFS AND
ECMWF ENSEMBLES FORECAST A RIDGE, WHILE OTHERS FORECAST A TROUGH, SO FORECAST
PROBABILITIES ARE LOWEST IN THE NORTHEASTERN U.S. TODAYS MANUAL 500-HPA HEIGHT
BLEND FAVORS THE 0Z ECMWF ENSEMBLE, WHICH RECENTLY HAS HAD THE HIGHEST SKILL
OUT OF ALL AVAILABLE MODELS.

THE HIGH AMPLITUDE ANOMALOUS RIDGING OVER THE GULF OF ALASKA STRONGLY FAVORS
ABOVE NORMAL TEMPERATURES IN ALASKA AND ALONG THE WEST COAST. FORECAST
PROBABILITIES ARE FAIRLY HIGH BECAUSE OF THE AMPLITUDE OF THE EXPECTED HEIGHT
ANOMALIES, AND THE PERSISTENCE OF THIS PATTERN IN RECENT FORECASTS. MODELS ARE
IN GOOD AGREEMENT ON ANOMALOUS TROUGHING OVER THE NORTHERN PLAINS AND ROCKIES.
SINCE THERE IS GOOD CONSISTENCY FROM RUN TO RUN, AND GOOD AGREEMENT AMONG THE
MODELS, BELOW NORMAL TEMPERATURES ARE STRONGLY FAVORED ACROSS MUCH OF THE GREAT
BASIN, ROCKIES, NORTHERN AND CENTRAL PLAINS, AND INTO THE GREAT LAKES.
ANOMALOUS RIDGING IN EASTERN CANADA IS EXPECTED TO EXTEND SOUTH INTO THE
NORTHEASTERN U.S., FAVORING ABOVE NORMAL TEMPERATURES THERE. RIDGING AND
LOW-LEVEL SOUTHERLY FLOW INCREASE THE CHANCES FOR ABOVE NORMAL TEMPERATURES IN
THE SOUTHERN U.S.

ANOMALOUS TROUGHING AND ASSOCIATED STORM SYSTEMS ARE EXPECTED NEAR ALASKA
DURING THE 6-10 DAY PERIOD, FAVORING ABOVE MEDIAN PRECIPITATION THROUGHOUT MUCH
OF THE STATE. RIDGING NEAR THE WEST COAST OF THE U.S. IS EXPECTED TO LIMIT
STORM SYSTEM ACTIVITY IN THE WESTERN U.S., INCREASING THE LIKELIHOOD FOR NEAR
TO BELOW MEDIAN PRECIPITATION IN THE WEST. WITH A FAIRLY STORMY PATTERN
EXPECTED OVER THE EASTERN TWO THIRDS OF THE CONUS, NEAR TO ABOVE MEDIAN
PRECIPITATION IS EXPECTED FOR MUCH OF THE REST OF THE CONUS, EXCEPT OVER
SOUTHERN TEXAS, WHERE THE LOW LEVEL FLOW IS EXPECTED TO ORIGINATE OVER MEXICO,
RATHER THAN THE GULF OF MEXICO, AND THEREFORE BE RELATIVELY DRY.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 30% OF TODAY`S 6Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,
AND 30% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
FAIRLY GOOD AGREEMENT AMONG THE MODELS AND TOOLS.

8-14 DAY OUTLOOK FOR AUG 27 - SEP 02, 2014

THE FORECAST CIRCULATION FOR WEEK-2 IS EXPECTED TO BE LESS AMPLIFIED, AND MORE
ZONAL, THAN DURING THE 6-10 DAY PERIOD. THERE IS A LOT MORE UNCERTAINTY IN THE
WEEK-2 PERIOD, AS IS TYPICAL. THE TEMPERATURE PROBABILITY FORECAST IS SIMILAR
TO THAT OF THE 6-10 DAY PERIOD, THOUGH PROBABILITIES ARE LOWER DUE TO THE
INCREASED UNCERTAINTY. THE AREA WHERE BELOW NORMAL TEMPERATURES ARE FAVORED IS
SMALLER AS SOUTHERLY FLOW IS EXPECTED TO BECOME MORE WIDESPREAD OVER THE WEST
CENTRAL U.S., FAVORING MODERATING TEMPERATURES THERE. ONE DIFFERENCE IN THE
PRECIPITATION PROBABILITY FORECAST IS THAT AS STORM SYSTEM ACTIVITY SHIFTS FROM
ALASKA INTO WESTERN CANADA BY THE WEEK-2 PERIOD, BELOW MEDIAN PRECIPITATION
BECOMES FAVORED FOR SOUTHERN ALASKA, WITH ABOVE MEDIAN PRECIPITATION FAVORED IN
NORTHERN ALASKA, AS LOW LEVEL WINDS ARE EXPECTED TO BECOME ANOMALOUSLY
NORTHERLY. IN ADDITION, THE LARGE SCALE PATTERN IS FORECAST TO BECOME MORE
FAVORABLE FOR SOUTHWEST MONSOON ACTIVITY, FAVORING ABOVE MEDIAN PRECIPITATION
FOR PARTS OF THE SOUTHWEST.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 40% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 11,
AND 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: NEAR AVERAGE, 3 OUT OF 5, DUE
TO ONLY FAIR AGREEMENT AMONG THE MODEL SOLUTIONS.

FORECASTER: MIKE CHARLES

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:
19610828 - 19560825 - 19860826 - 19640819 - 19920803


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:
19560826 - 19860828 - 19660825 - 19640819 - 19550830


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 25 - 29 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    N     COLORADO    B    N
NEW MEXICO  N    N     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    B    A     KANSAS      B    A     OKLAHOMA    A    A
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    B
MINNESOTA   B    A     IOWA        B    A     MISSOURI    A    A
ARKANSAS    A    A     LOUISIANA   A    N     WISCONSIN   B    A
ILLINOIS    N    A     MISSISSIPPI A    A     MICHIGAN    B    A
INDIANA     N    A     OHIO        N    A     KENTUCKY    N    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N
MASS        A    N     CONN        A    N     RHODE IS    A    N
PENN        N    A     NEW JERSEY  N    A     W VIRGINIA  N    A
MARYLAND    N    A     DELAWARE    N    A     VIRGINIA    N    A
N CAROLINA  N    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  A    N
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    B



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 27 - SEP 02, 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    B     NEVADA      A    N
W MONTANA   N    B     E MONTANA   B    N     WYOMING     B    N
UTAH        N    A     ARIZONA     N    A     COLORADO    N    N
NEW MEXICO  N    N     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    B    A     KANSAS      N    A     OKLAHOMA    A    A
N TEXAS     A    N     S TEXAS     A    B     W TEXAS     A    N
MINNESOTA   B    A     IOWA        B    A     MISSOURI    N    A
ARKANSAS    A    A     LOUISIANA   A    N     WISCONSIN   B    A
ILLINOIS    B    A     MISSISSIPPI A    A     MICHIGAN    B    A
INDIANA     N    A     OHIO        N    A     KENTUCKY    N    A
TENNESSEE   N    A     ALABAMA     A    A     NEW YORK    N    A
VERMONT     N    A     NEW HAMP    A    A     MAINE       A    A
MASS        N    A     CONN        N    A     RHODE IS    N    A
PENN        N    A     NEW JERSEY  N    A     W VIRGINIA  N    A
MARYLAND    N    A     DELAWARE    N    A     VIRGINIA    N    A
N CAROLINA  N    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  N    A
AK ALEUTIAN A    N     AK WESTERN  A    N     AK INT BSN  N    N
AK S INT    A    B     AK SO COAST A    B     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.

$$



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