Prognostic Meteorological Discussion
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FXUS06 KWBC 181911
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED APRIL 18 2018

6-10 DAY OUTLOOK FOR APR 24 - 28 2018

TODAY`S VARIOUS ENSEMBLE MEAN SOLUTIONS ARE IN FAIR AGREEMENT ON THE 6-10 DAY
PATTERN OVER THE FORECAST DOMAIN. THE MANUAL BLEND AT 500-HPA FORECASTS AN
ANOMALOUS TROUGH OVER THE BERING SEA AND WESTERN MAINLAND ALASKA, POSITIVE
HEIGHT ANOMALIES OVER THE WESTERN HALF OF THE CONUS AND THE NORTHEAST, AND WEAK
NEGATIVE HEIGHT ANOMALIES OVER MUCH OF THE SOUTHEAST. TODAY`S MANUAL 500-HPA
BLEND SLIGHTLY FAVORS THE 0Z ECMWF ENSEMBLE MEAN, DUE TO ITS HIGHER RECENT
500-HPA FORECAST SKILL.

NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE EASTERN CONUS,
DUE TO THE PASSAGE OF SEVERAL COLD FRONTS. ABOVE NORMAL TEMPERATURES ARE
FAVORED OVER MUCH OF THE WESTERN CONUS, WHERE NEAR TO ABOVE NORMAL HEIGHTS ARE
PREDICTED. NEAR TO ABOVE NORMAL TEMPERATURES ARE FAVORED OVER MUCH OF ALASKA,
CONSISTENT WITH REFORECAST-CALIBRATED GEFS AND ECMWF TOOLS AND ABOVE NORMAL SST
IN SURROUNDING AREAS. BELOW NORMAL TEMPERATURES ARE FAVORED OVER SOUTHEASTERN
MAINLAND ALASKA AND THE ALASKA PANHANDLE, CONSISTENT WITH FORECAST TOOLS.

MUCH OF THE NORTHWESTERN CONUS TO PARTS OF THE NORTHERN PLAINS ARE FAVORED TO
REMAIN RELATIVELY DRY, CONSISTENT WITH DYNAMICAL FORECAST TOOLS. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR PARTS OF CALIFORNIA AND NEVADA AS WELL AS MUCH OF
CENTRAL AND SOUTHERN ROCKIES AND HIGH PLAINS IN ASSOCIATION WITH A MEAN 500-HPA
TROUGH PREDICTED OVER THE SOUTHWESTERN CONUS. BELOW NORMAL PRECIPITATION IS
FAVORED FOR PARTS OF THE SOUTH-CENTRAL CONUS AND MUCH OF THE LOWER AND MIDDLE
MISSISSIPPI VALLEY, CONSISTENT WITH VARIOUS FORECAST TOOLS. A PREDICTED MEAN
500-HPA TROUGH OVER MUCH OF THE EAST COAST ENHANCES PROBABILITIES OF ABOVE
NORMAL PRECIPITATION THERE. SEVERAL PREDICTED STORM SYSTEMS IN THE GULF OF
ALASKA INCREASE THE LIKELIHOOD OF ABOVE NORMAL PRECIPITATION FOR MUCH OF
ALASKA.

THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY`S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY`S GFS SUPERENSEMBLE MEAN 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, 10% OF TODAY`S OPERATIONAL 0Z
ECMWF CENTERED ON DAY 8, AND 10% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED
ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: NEAR AVERAGE, 3 OUT OF 5, DUE TO
FAIR OVERALL AGREEMENT AMONG THE AVAILABLE FORECAST TOOLS.

8-14 DAY OUTLOOK FOR APR 26 - MAY 02, 2018

THE FORECAST 500-HPA HEIGHT PATTERN FOR WEEK-2 IS SIMILAR TO THE 6-10 DAY
FORECAST PATTERN BUT WITH RELATIVELY LOW AMPLITUDE, LIKELY DUE TO INCREASED
ENSEMBLE SPREAD IN THE WEEK-2 PERIOD.

THE TEMPERATURE PROBABILITY FORECAST DURING THE WEEK-2 PERIOD IS GENERALLY
SIMILAR TO THE 6-10 DAY PERIOD.

MUCH OF THE NORTHWESTERN CONUS IS FAVORED TO REMAIN RELATIVELY DRY, CONSISTENT
WITH DYNAMICAL FORECAST TOOLS. THE PREDICTED STORM TRACK ACROSS SOUTHERN
CALIFORNIA, THE SOUTHERN PLAINS, AND LOWER MISSISSIPPI VALLEY INCREASES
PROBABILITIES OF ABOVE NORMAL PRECIPITATION THERE. A FORECAST 500-HPA MEAN
TROUGH OVER THE NORTHEAST FAVORS NEAR TO ABOVE NORMAL PRECIPITATION OVER PARTS
OF THE GREAT LAKES AND THE NORTHEAST. BELOW NORMAL PRECIPITATION IS FAVORED FOR
MUCH OF THE SOUTHEAST U.S., CONSISTENT WITH DYNAMICAL FORECAST TOOLS. SEVERAL
STORM SYSTEMS FORECAST OVER THE GULF OF ALASKA ENHANCE PROBABILITIES OF ABOVE
NORMAL PRECIPITATION FOR MUCH OF ALASKA.

THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% OF TODAY`S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY`S GFS SUPERENSEMBLE MEAN
CENTERED ON DAY 11, 10% OF TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 40%
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: BELOW AVERAGE, 2 OUT OF 5, DUE TO
FAIRLY POOR MODEL AGREEMENT WITH A RELATIVELY LOW-AMPLITUDE CIRCULATION PATTERN.

FORECASTER: Y. FAN

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
APRIL 19.

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:
20030422 - 19950415 - 19790414 - 19860412 - 19550426


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:
20030423 - 19950415 - 19860412 - 19550426 - 19830423


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR APR 24 - 28 2018

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR APR 26 - MAY 02, 2018

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