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FXUS06 KWBC 252011
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 25 2018

6-10 DAY OUTLOOK FOR MAY 01 - 05 2018

TODAY`S ENSEMBLE MEAN FORECASTS ARE IN GOOD AGREEMENT ON THE PREDICTED
CIRCULATION PATTERN DURING THE 6-10 DAY PERIOD. HIGH RESOLUTION RUNS AND
ENSEMBLE MODELS PREDICT A RIDGE OVER THE EASTERN CONUS AND A TROUGH OVER THE
WESTERN CONUS. ABOVE-NORMAL 500-HPA HEIGHTS ARE FAVORED FOR THE EASTERN AND
NORTHWESTERN CONUS, WHILE BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST OVER THE
SOUTHWESTERN CONUS. TODAY`S MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON
THE ENSEMBLE MEAN SOLUTIONS FROM THE GEFS, ECMWF, AND CANADIAN MODEL SUITES.

UNDER A PREDICTED RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES, ABOVE NORMAL
TEMPERATURES ARE MOST LIKELY FROM THE SOUTHERN PLAINS ACROSS THE MISSISSIPPI
VALLEY INTO THE MID-ATLANTIC AND NORTHEAST. BELOW NORMAL TEMPERATURES ARE MOST
LIKELY FOR PARTS OF THE WEST-CENTRAL AND SOUTHWESTERN CONUS, INCLUDING THE
CENTRAL AND SOUTHERN ROCKY MOUNTAINS AND THE NORTHERN PLAINS. PROBABILITIES OF
ABOVE NORMAL TEMPERATURES ARE ENHANCED OVER THE NORTHWEST AS INDICATED BY A
CONSOLIDATION OF REFORECAST-CALIBRATED TEMPERATURES FROM THE ECMWF AND GEFS
ENSEMBLES. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR WESTERN AND NORTHERN
ALASKA, AHEAD OF A TROUGH OVER THE BERING SEA, AS WELL AS SOUTHERN PARTS OF THE
ALASKA PANHANDLE, UNDER A PREDICTED RIDGE. BELOW NORMAL TEMPERATURES ARE FAVORED
FOR MUCH OF SOUTHEASTERN MAINLAND ALASKA.

IN ASSOCIATION WITH A PREDICTED TROUGH, ENHANCED PROBABILITIES OF ABOVE NORMAL
PRECIPITATION OVER MUCH OF THE SOUTHWESTERN CONUS ARE PREDICTED, AS WELL AS
OVER THE SOUTHERN PLAINS AND THE MISSISSIPPI VALLEY, WITH NORTHWARD MOISTURE
FLOW AROUND SURFACE HIGH PRESSURE. PROBABILITIES OF BELOW NORMAL PRECIPITATION
ARE ENHANCED FOR THE NORTHWESTERN CONUS AND THE SOUTHERN ALASKA PANHANDLE,
UNDER A PREDICTED RIDGE. BELOW NORMAL PRECIPITATION IS FAVORED ALONG MUCH OF
THE EASTERN SEABOARD UNDER ANOMALOUS NORTHERLY 500-HPA FLOW. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR MUCH OF ALASKA, AHEAD OF A PREDICTED TROUGH.

THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% OF TODAY`S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 20% OF TODAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 20% 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 OVERALL AGREEMENT AMONG THE AVAILABLE FORECAST TOOLS.

8-14 DAY OUTLOOK FOR MAY 03 - 09 2018

A 500-HPA TROUGH IS FORECAST TO SHIFT EAST ACROSS THE NORTH-CENTRAL CONUS EARLY
IN WEEK-2. ABOVE NORMAL HEIGHTS ARE EXPECTED TO BE WEAKER OVER MUCH OF THE
EASTERN CONUS THAN FORECAST FOR THE 6-10 DAY PERIOD. ABOVE NORMAL HEIGHTS ARE
ANTICIPATED OVER MUCH OF THE WESTERN CONUS. SPREAD AMONG ENSEMBLE MEMBERS IS
MODERATE TO LARGE DURING WEEK-2 INDICATIVE OF INCREASED UNCERTAINTY DURING THIS
TIME PERIOD.

ABOVE NORMAL TEMPERATURES ARE MORE LIKELY OVER THE WESTERN CONUS UNDER ABOVE
NORMAL HEIGHTS. BELOW NORMAL TEMPERATURES ARE MOST LIKELY FOR MUCH OF THE
CENTRAL CONUS CONSISTENT WITH EASTWARD PROGRESSION OF THE PREDICTED TROUGH.
PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE ELEVATED FOR THE EASTERN CONUS
DUE TO SOUTHERLY FLOW AROUND SURFACE HIGH PRESSURE. ABOVE NORMAL TEMPERATURES
ARE FAVORED FOR WESTERN ALASKA, THE ALEUTIANS, AND THE SOUTHERN ALASKA
PANHANDLE WITH A FORECAST OF RIDGING. BELOW NORMAL TEMPERATURES ARE FAVORED FOR
PARTS OF SOUTHEASTERN MAINLAND ALASKA CONSISTENT WITH THE GEFS REFORECAST
GUIDANCE.

THE WEEK 2 PRECIPITATION OUTLOOK IS SIMILAR TO THE 6-10 DAY OUTLOOK, ALTHOUGH
AREAS OF BELOW NORMAL PRECIPITATION IN THE WESTERN CONUS HAVE EXTENDED TO THE
NORTHERN HIGH PLAINS BUT WITH REDUCED PROBABILITIES AS UNCERTAINTY IN THE
PREDICTED CIRCULATION PATTERN INCREASES. ABOVE NORMAL PRECIPITATION REMAINS
MOST LIKELY OVER PARTS OF THE SOUTHWESTERN AND SOUTH-CENTRAL CONUS. THE AREA OF
ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION OVER THE MISSISSIPPI
VALLEY HAS SHIFTED SLIGHTLY EASTWARD, RESULTING IN A REDUCTION OF BELOW NORMAL
PRECIPITATION AREAS OVER THE EAST COAST.

THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY`S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY`S GFS SUPERENSEMBLE MEAN
CENTERED ON DAY 11, 20% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY
11, 20% OF YESTERDAY`S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, 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
A CHANGING CIRCULATION PATTERN AND GREATER UNCERTAINTY IN THE ENSEMBLE
FORECASTS, ALONG WITH SOME DISAGREEMENT IN THE TEMPERATURE AND PRECIPITATION
TOOLS.

FORECASTER: QIN Z

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 MAY
17.

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:
19640407 - 19590507 - 20060503 - 19850414 - 19570424


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:
19640406 - 19980502 - 19740426 - 19790426 - 20060502


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 01 - 05 2018

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 03 - 09 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    A
W MONTANA   A    B     E MONTANA   N    B     WYOMING     A    B
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    N    B     S DAKOTA    N    B
NEBRASKA    N    N     KANSAS      B    A     OKLAHOMA    B    A
N TEXAS     B    A     S TEXAS     N    A     W TEXAS     N    A
MINNESOTA   B    N     IOWA        B    N     MISSOURI    B    A
ARKANSAS    B    A     LOUISIANA   N    A     WISCONSIN   B    N
ILLINOIS    B    A     MISSISSIPPI N    A     MICHIGAN    B    A
INDIANA     B    A     OHIO        B    N     KENTUCKY    N    A
TENNESSEE   N    A     ALABAMA     N    N     NEW YORK    A    N
VERMONT     A    A     NEW HAMP    A    N     MAINE       A    A
MASS        A    N     CONN        A    N     RHODE IS    A    N
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    A
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    B
FL PNHDL    A    B     FL PENIN    A    B     AK N SLOPE  N    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  N    A
AK S INT    B    A     AK SO COAST B    A     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.

$$




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