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FXUS06 KWBC 261947
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU APRIL 26 2018

6-10 DAY OUTLOOK FOR MAY 02 - 06 2018

AT THE BEGINNING OF THE 6-10 DAY PERIOD, TODAY`S ENSEMBLE MEAN SOLUTIONS DEPICT
500-HPA TROUGHS OVER THE NORTH-CENTRAL AND SOUTHWESTERN CONUS AS WELL AS OVER
WESTERN ALASKA WHILE RIDGES ARE ANTICIPATED OVER THE SOUTHEASTERN CONUS AND
EASTERN ALASKA. BY THE END OF THE PERIOD, THE TROUGHS OVER THE NORTH-CENTRAL
AND SOUTHWESTERN CONUS ARE EXPECTED TO PROGRESS EASTWARD AND PHASE OVER THE
EASTERN CONUS WHILE A RIDGE BUILDS OVER THE WESTERN CONUS. OVER ALASKA, THE
RIDGE OVER EASTERN PORTIONS OF THE STATE IS EXPECTED TO PERSIST THROUGH THE
PERIOD WHILE TROUGHING CONTINUES OVER THE BERING SEA. THE 500-HPA HEIGHT BLEND,
BASED ON THE ENSEMBLE MEAN SOLUTIONS, DEPICTS ABOVE NORMAL HEIGHTS ACROSS THE
EASTERN SEABOARD, THE NORTHWESTERN CONUS, AND SOUTHEASTERN ALASKA. NEAR TO
BELOW NORMAL HEIGHTS ARE EXPECTED FOR THE CENTRAL AND SOUTHWESTERN CONUS AS
WELL AS WESTERN AND NORTHERN ALASKA.

AS TROUGHS OVER THE SOUTHWESTERN AND NORTH-CENTRAL CONUS PROGRESS EASTWARD
TOWARD THE EASTERN CONUS, A STRIPE OF ENHANCED PROBABILITIES OF BELOW NORMAL
TEMPERATURES IS INDICATED FOR PARTS OF THE CENTRAL CONUS. RIDGING EARLY IN THE
PERIOD LEADS TO INCREASED CHANCES OF ABOVE NORMAL TEMPERATURES FROM THE EASTERN
SEABOARD TO PARTS OF THE GULF COAST REGION. ABOVE NORMAL TEMPERATURES ARE ALSO
FAVORED FOR THE NORTHWESTERN CONUS AS A RIDGE ESTABLISHES ITSELF OVER THE
REGION BY THE MIDDLE OF THE PERIOD. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR
WESTERN AND NORTHERN ALASKA AHEAD OF A TROUGH OVER THE EASTERN BERING SEA.
PERSISTENT RIDGING OVER EASTERN ALASKA LEADS TO INCREASED ODDS OF ABOVE NORMAL
TEMPERATURES FOR PARTS OF THE ALASKA PANHANDLE.

ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE FOUR CORNERS REGION IN
ASSOCIATION WITH A TROUGH OVER THE SOUTHWESTERN CONUS EARLY IN THE PERIOD. AS
THIS TROUGH PROGRESSES EASTWARD, GULF MOISTURE IS EXPECTED TO BE DRAWN
NORTHWARD, LEADING TO INCREASED ODDS OF ABOVE NORMAL PRECIPITATION FROM THE
SOUTHERN PLAINS AND THE WESTERN AND CENTRAL GULF COAST REGION NORTHEASTWARD
ACROSS MUCH OF THE EAST-CENTRAL CONUS. RIDGING EARLY IN THE PERIOD SLIGHTLY
FAVORS BELOW NORMAL PRECIPITATION FOR PARTS OF THE FLORIDA PENINSULA. BELOW
NORMAL PRECIPITATION IS ALSO FAVORED FOR THE NORTHWESTERN CONUS EXTENDING TO
PARTS OF THE NORTHERN PLAINS AS HEIGHTS RISE ACROSS THESE REGIONS. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR WESTERN ALASKA AHEAD OF A TROUGH OVER THE EASTERN
BERING SEA.

THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY`S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% 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: NEAR AVERAGE, 3 OUT OF 5, DUE TO
RELATIVELY GOOD OVERALL MODEL AGREEMENT OFFSET BY AN ANTICIPATED PATTERN CHANGE
ACROSS MUCH OF THE FORECAST DOMAIN.

8-14 DAY OUTLOOK FOR MAY 04 - 10 2018

DURING WEEK-2, THE GEFS AND ECMWF ENSEMBLE MEANS FORECAST A MEAN LONGWAVE
TROUGH OVER EASTERN NORTH AMERICA WHILE A MEAN RIDGE IS EXPECTED OVER THE
WESTERN CONUS EXTENDING TO EASTERN ALASKA. A MEAN TROUGH IS ANTICIPATED TO
PERSIST UPSTREAM OVER THE EASTERN BERING SEA. THE MANUAL 500-HPA HEIGHT BLEND
IS BASED ON THE ENSEMBLE MEAN SOLUTIONS AND FEATURES ABOVE NORMAL HEIGHTS
ACROSS THE WESTERN CONUS AND EASTERN ALASKA. NEAR TO BELOW NORMAL HEIGHTS ARE
ANTICIPATED FOR PARTS OF THE EASTERN CONUS AND WESTERN ALASKA.

ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE WESTERN CONUS DUE TO RIDGING
WHILE A MEAN TROUGH OVER THE EASTERN CONUS LEADS TO INCREASED CHANCES OF BELOW
NORMAL TEMPERATURES FOR MUCH OF THE EAST-CENTRAL CONUS. NEAR TO ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR ALASKA AHEAD OF A TROUGH OVER THE EASTERN BERING
SEA.

THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION FROM THE EASTERN
SEABOARD TO THE SOUTHERN PLAINS IN ASSOCIATION WITH TROUGH DEVELOPMENT OVER
EASTERN NORTH AMERICA. RIDGING AND RISING HEIGHTS ACROSS THE WESTERN AND
NORTH-CENTRAL CONUS LEAD TO ENHANCED PROBABILITIES OF NEAR TO BELOW NORMAL
PRECIPITATION FOR THESE REGIONS. NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED
FOR ALASKA AHEAD OF A MEAN TROUGH OVER THE EASTERN BERING SEA.

THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY`S 0Z GFS
ENSEMBLE MEAN 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: AVERAGE, 3 OUT OF 5, DUE FAIRLY
GOOD AGREEMENT ON THE OVERALL 500-HPA PATTERN OFFSET BY FAIRLY LARGE
DIFFERENCES AMONG THE PRECIPITATION TOOLS ACROSS PARTS OF THE FORECAST DOMAIN.

FORECASTER: SCOTT H

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.





6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 02 - 06 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     N    N
UTAH        N    A     ARIZONA     N    A     COLORADO    B    A
NEW MEXICO  B    A     N DAKOTA    N    B     S DAKOTA    B    B
NEBRASKA    B    N     KANSAS      B    N     OKLAHOMA    N    A
N TEXAS     N    A     S TEXAS     A    A     W TEXAS     B    N
MINNESOTA   B    N     IOWA        N    N     MISSOURI    N    A
ARKANSAS    N    A     LOUISIANA   A    A     WISCONSIN   N    N
ILLINOIS    N    A     MISSISSIPPI A    A     MICHIGAN    N    A
INDIANA     N    A     OHIO        A    A     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A
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    N
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    N    B     AK N SLOPE  A    A
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  N    N
AK S INT    N    A     AK SO COAST N    A     AK PNHDL    A    N



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 04 - 10 2018

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

$$




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