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FXUS06 KWBC 271901
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 27 2017

6-10 DAY OUTLOOK FOR MAY 03 - 07 2017

TODAY`S DYNAMICAL MODEL SOLUTIONS FOR THE 6-10 DAY PERIOD ARE IN GOOD AGREEMENT
ON THE EXPECTED 500-HPA CIRCULATION PATTERN OVER MOST OF NORTH AMERICA. TROUGHS
ARE PREDICTED OVER THE EASTERN CONUS AND THE BERING SEA/ALEUTIANS, WHILE RIDGES
ARE ANTICIPATED OVER THE WEST-CENTRAL ATLANTIC AND THE NORTHWESTERN CONUS
EXTENDING NORTH/NORTHWESTWARD TO WESTERN CANADA AND ALASKA. TROUGH ENERGY IS
EXPECTED TO START UNDERCUTTING THE RIDGE FORECAST OVER THE PACIFIC NORTHWEST.
THE 0Z GFS ENSEMBLE MEAN IS A BIT MORE AMPLIFIED WITH THE EXPECTED CIRCULATION
PATTERN AND SOMEWHAT FURTHER EAST WITH THE TROUGH PREDICTED NEAR THE ALEUTIANS.
ENSEMBLE SPREAD IS LOW TO MODERATE OVER THE EASTERN CONUS, AND MODERATE TO HIGH
OVER THE WEST. TODAY`S OFFICIAL 500-HPA MANUAL HEIGHT BLEND INDICATES NEAR TO
ABOVE NORMAL HEIGHTS OVER THE WESTERN CONUS, WHILE NEAR TO BELOW NORMAL HEIGHTS
ARE EXPECTED OVER THE CENTRAL AND EASTERN CONUS AND ALASKA.

ABOVE NORMAL HEIGHTS ENHANCE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR
MOST OF THE SOUTHWESTERN CONUS, WHILE BELOW NORMAL HEIGHTS FAVOR BELOW NORMAL
TEMPERATURES FOR MOST OF THE CENTRAL AND EAST-CENTRAL CONUS. ANOMALOUS
EAST-SOUTHEASTERLY FLOW AND ABOVE NORMAL SEA SURFACE TEMPERATURES ENHANCE
PROBABILITIES FOR NEAR TO ABOVE NORMAL TEMPERATURES FOR ALASKA.

THE TROUGH FORECAST OVER THE EASTERN CONUS FAVORS ABOVE MEDIAN PRECIPITATION
FOR MUCH OF THE EASTERN U.S. ANOMALOUS NORTH/NORTHWESTERLY FLOW TILTS THE ODDS
TO BELOW MEDIAN PRECIPITATION FOR PARTS OF THE PLAINS, GREAT LAKES, AND
MISSISSIPPI VALLEY. SHORTWAVE ENERGY RIDING OVER THE TOP OF THE RIDGE FORECAST
OVER THE NORTHWESTERN CONUS ENHANCES PROBABILITIES FOR ABOVE MEDIAN
PRECIPITATION FOR PARTS OF THE NORTHERN PLAINS, NORTHERN ROCKIES, CENTRAL GREAT
BASIN, AND THE SOUTHWEST. BELOW NORMAL HEIGHTS AND THE TROUGH FORECAST OVER THE
BERING SEA ENHANCE PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR THE ALASKA
PANHANDLE AND PARTS OF SOUTHEASTERN ALASKA, WHILE RIDGING FAVORS BELOW MEDIAN
PRECIPITATION FOR PARTS OF NORTHWESTERN ALASKA.

TODAY`S OFFICIAL 500-HPA 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 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF YESTERDAY`S 12Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, AND 20% OF TODAY`S 0Z CANADIAN
ENSEMBLE MEAN CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT ON A MODERATELY AMPLIFIED PATTERN FOR MUCH OF THE FORECAST
DOMAIN AND FAIRLY GOOD AGREEMENT AMONG THE FORECAST TOOLS, OFFSET BY MODERATE
SPREAD AMONG THE ENSEMBLE MEMBERS AND THE EXPECTATION OF A PROGRESSIVE FLOW
PATTERN.

8-14 DAY OUTLOOK FOR MAY 05 - 11 2017

COMPARED TO THE 6-10 DAY PERIOD, THE OVERALL CIRCULATION PATTERN IS EXPECTED TO
BE PROGRESSIVE AND DEAMPLIFIED DURING WEEK-2. TROUGHS ARE FORECAST OVER THE
NORTHEASTERN AND SOUTHWESTERN CONUS AND THE BERING SEA/ALEUTIANS, WHILE RIDGES
ARE ANTICIPATED OVER THE CENTRAL CONUS AND WESTERN CANADA EXTENDING
NORTH-NORTHWESTWARD OVER ALASKA. THE ENSEMBLE SPAGHETTI CHARTS INDICATE
RELATIVELY HIGH SPREAD ACROSS MOST OF THE FORECAST DOMAIN WITH LARGE
DIFFERENCES NOTED IN BOTH AMPLITUDE AND PHASE OF INDIVIDUAL SHORTWAVE FEATURES.
TODAY`S WEEK-2 BLENDED 500-HPA HEIGHT CHART INDICATES A RELATIVELY WEAK HEIGHT
ANOMALY PATTERN, DUE TO THE HIGH SPREAD AMONG ENSEMBLE MEMBERS. NEAR TO BELOW
NORMAL HEIGHTS ARE PREDICTED OVER THE EASTERN AND SOUTHERN CONUS, WHILE NEAR TO
ABOVE NORMAL HEIGHTS ARE ANTICIPATED OVER THE MUCH OF THE NORTHWESTERN AND
NORTH-CENTRAL CONUS AND ALASKA.

BELOW NORMAL HEIGHTS ENHANCE PROBABILITIES FOR BELOW NORMAL TEMPERATURES FOR
MUCH OF THE EASTERN THIRD OF THE CONUS. NEAR TO ABOVE NORMAL HEIGHTS FAVOR NEAR
TO ABOVE NORMAL TEMPERATURES FOR MOST OF THE WESTERN TWO-THIRDS OF THE CONUS.
THE EXCEPTION IS OVER PARTS OF THE NORTHWEST CONUS WHERE NORTHEASTERLY SURFACE
FLOW TILTS THE ODDS TO BELOW NORMAL TEMPERATURES. ABOVE NORMAL HEIGHTS ENHANCE
PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR WESTERN AND CENTRAL ALASKA.

THE PREDICTED TROUGH OVER THE NORTHEAST U.S. FAVORS ABOVE MEDIAN PRECIPITATION
FOR PARTS OF THE NORTHEAST CONUS. ANOMALOUS NORTH/NORTHWESTERLY MID-LEVEL FLOW
AND DESCENT ON THE REAR SIDE OF THE NORTHEAST TROUGH ENHANCES PROBABILITIES FOR
BELOW MEDIAN PRECIPITATION FOR THE CENTRAL AND EAST-CENTRAL CONUS. THE TROUGH
OVER THE SOUTHWEST U.S. TILTS THE ODDS TO ABOVE MEDIAN PRECIPITATION FOR MUCH
OF THE INTERIOR WESTERN CONUS. ABOVE NORMAL HEIGHTS FAVORS BELOW MEDIAN
PRECIPITATION FOR NORTHERN CALIFORNIA AND MOST OF OREGON. THE TROUGH NEAR THE
ALEUTIANS FAVORS ABOVE MEDIAN PRECIPITATION FOR THAT REGION, SOUTH COASTAL
ALASKA, AND THE ALASKA PANHANDLE. RIDGING ENHANCES PROBABILITIES FOR BELOW
MEDIAN PRECIPITATION FOR PARTS OF CENTRAL ALASKA.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 25% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 10% 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 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF YESTERDAY`S 12Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 10, AND 10% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN
CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: MUCH BELOW AVERAGE, 1 OUT OF 5,
DUE TO FAIRLY GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFFSET BY LARGE
SPREAD AMONG INDIVIDUAL ENSEMBLE MEMBERS, DISAGREEMENT AMONG MANY OF THE
FORECAST TOOLS, AND RELATIVELY WEAK HEIGHT ANOMALIES.

FORECASTER: RANDY S

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
18

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:
19930427 - 20040421 - 19800407 - 19730415 - 19960421


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:
19930427 - 19960421 - 19510424 - 19730415 - 19800407


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 03 - 07 2017

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 05 - 11 2017

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

                           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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