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6-10 Day outlooks are issued daily between 3pm & 4pm Eastern Time. All forecasts issued on weekends are completely automated while all weekday outlooks are modified by the forecaster.
 
Please refer to the U.S. Prognostic Discussion for an explanation of terms and symbols used on these maps.


 
 
HOME> Outlook Maps> Prognostic Map Discussion
 
Prognostic Discussions
Valid: Apr 26 - 30, 2015 (6-10 Day Outlook)
Valid: Apr 28 - May 04, 2015 (8-14 Day Outlook)
Issued: Apr 20, 2015

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EDT MON APRIL 20 2015 
 
6-10 DAY OUTLOOK FOR APR 26 - 30 2015 
 
TODAY'S ENSEMBLE MODEL SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE 500-HPA  
FLOW PATTERN EXPECTED OVER MUCH OF NORTH AMERICA AND VICINITY. ALL MODELS ARE  
FORECASTING A TROUGH OVER THE GULF OF ALASKA, AND A RIDGE OVER THE WESTERN AND  
CENTRAL CONUS. FARTHER TO THE EAST, A CLOSED 500-HPA LOW IS PREDICTED BY ALL OF  
TODAY'S MODEL SOLUTIONS OVER NORTHEASTERN NORTH AMERICA WITH NEGATIVE 500-HPA  
HEIGHT ANOMALIES FORECAST OVER THE EASTERN CONUS.       
 
BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE GREAT LAKES AND EASTERN  
CONUS IN ASSOCIATION WITH BELOW NORMAL 500-HPA HEIGHTS. ABOVE NORMAL  
TEMPERATURES ARE FAVORED FOR THE FLORIDA PENINSULA AND ALONG THE GULF COAST  
CONSISTENT WITH BIAS CORRECTED TEMPERATURES FROM THE ECMWF, GFS, AND CANADIAN  
ENSEMBLES, AND WITH GEFS REFORECAST GUIDANCE. RIDGING OVER NORTHWESTERN NORTH  
AMERICA INCREASES THE CHANCES FOR ABOVE NORMAL TEMPERATURES FOR THE CENTRAL  
CONUS. ANOMALOUS SOUTHEASTERLY FLOW FROM A LOW PRESSURE PREDICTED OVER THE GULF  
OF ALASKA LEADS TO ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR  
EASTERN AND CENTRAL ALASKA, THE ALEUTIANS AND THE ALASKA PANHANDLE.    
 
BELOW MEDIAN PRECIPITATION IS FAVORED FOR THE GREAT LAKES WEST OF A CLOSED  
500-HPA LOW PREDICTED OVER EASTERN NORTH AMERICA. PROBABILITIES OF BELOW MEDIAN  
PRECIPITATION ARE ENHANCED NEAR THE RIDGE POSITION OVER THE SOUTHERN CONUS.  
ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION ARE INDICATED FOR MUCH OF  
THE NORTHWESTERN CONUS IN ASSOCIATION WITH A MEAN TROUGH PREDICTED OFF THE WEST  
COAST. ABOVE MEDIAN PRECIPITATION IS ALSO FAVORED FOR THE SOUTHEASTERN COUNS  
CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GFS AND ECMWF CALIBRATED  
REFORECAST TOOLS. EXCEPT FOR THE ALASKA PANHANDLE, THERE ARE ENHANCED CHANCE OF  
BELOW MEDIAN PRECIPITATION FOR ALASKA AND THE ALEUTIANS  WEST OF A TROUGH  
PREDICTED OVER THE GULF OF ALASKA.  
 
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 10% 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 YESTERDAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 7, 20% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 7, AND 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN  
CENTERED ON DAY 8  
  
 
MODEL OF THE DAY: NO PREFERENCE  
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY  
GOOD ENSEMBLE MEAN AGREEMENT OFFSET BY LARGE SPREAD AMONG ENSEMBLE MEMBERS OVER  
THE NORTHERN CONUS 
 
8-14 DAY OUTLOOK FOR APR 28 - MAY 04, 2015  
 
TODAY'S WEEK TWO ENSEMBLE MEAN SOLUTIONS DEPICT MEAN 500-HPA TROUGHS OVER THE  
GULF OF ALASKA AND OVER SOUTHEASTERN CANADA, WITH A RIDGE OVER WESTERN CANADA  
AND MUCH OF CENTRAL CONUS. A TROUGH IS FORECAST OFF THE WEST COAST OF THE NORTH  
AMERICA WITH AN ENERGETIC SHORT WAVE NEAR THE SOUTHWESTERN CONUS. MODEL SPREAD  
IS FAIRLY HIGH OVER MUCH OF NORTH AMERICA DURING THE OUTLOOK PERIOD, ESPECIALLY  
IN THE NORTHERN STREAM. AS A RESULT OF THIS UNCERTAINTY, TODAY'S WEEK TWO  
500-HPA MANUAL HEIGHT BLEND IS BASED PRIMARILY ON THE ENSEMBLE MEAN SOLUTIONS. 
 
ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE ENHANCED FOR ALASKA, THE ALEUTIANS  
AND THE ALASKA PANHANDLE IN ASSOCIATION WITH THE POSITIVE 500-HPA HEIGHT  
ANOMALIES. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF EASTERN CONUS AND  
THE GULF COAST NEAR THE FORECAST TROUGH EXCEPT THE FLORIDA PENINSULA.  
ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE SOUTHERN PLATEAU, THE  
CENTRAL AND SOUTHERN HIGH PLAINS RELATED TO THE POSITIVE 500-HPA ANOMALIES  
PREDICTED. 
 
PROBABILITIES OF BELOW MEDIAN PRECIPITATION ARE ENHANCED WEST OF THE PREDICTED  
TROUGH FOR PARTS OF THE CENTRAL PLAINS, UPPER MISSISSIPPI VALLEY, AND THE GREAT  
LAKES. ENHANCED PROBABILITIES OF BELOW MEDIAN PRECIPITATION ARE INDICATED FOR  
MUCH OF THE WESTERN CONUS IN ASSOCIATION WITH A MEAN RIDGE PREDICTED.  ABOVE  
MEDIAN PRECIPITATION IS FAVORED FOR THE WESTERN TEXAS, NORTHWESTERN AND  
SOUTHEAST COAST CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GFS AND ECMWF  
CALIBRATED REFORECAST TOOLS. THERE ARE ENHANCED PROBABILITIES OF BELOW MEDIAN  
PRECIPITATION FOR ALASKA AND THE ALEUTIANS WEST OF THE TROUGH FORECAST OVER THE  
GULF OF ALASKA. 
 
 
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 20% OF TODAY'S 6Z GFS ENSEMBLE  
MEAN CENTERED ON DAY 11, 20% OF YESTERDAY'S GFS SUPERENSEMBLE MEAN CENTERED ON  
DAY 10, 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 IS: AVERAGE, 3 OUT OF 5, DUE TO  
RELATIVELY GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFFSET BY LARGE  
SPREAD AMONG THE COMPONENT ENSEMBLE MEMBERS OVER MUCH OF NORTH AMERICA 
 
FORECASTER: QIN GINGER ZHANG 
 
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  
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:  
19690414 - 19640407 - 19740412 - 19800331 - 20070424 
 
 
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:  
19800331 - 19940503 - 19690412 - 19640406 - 19620401 
 
 
6-10 DAY OUTLOOK TABLE 
OUTLOOK FOR APR 26 - 30 2015 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    A     OREGON      N    A     NRN CALIF   B    A      
SRN CALIF   N    B     IDAHO       A    A     NEVADA      N    N      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     A    N      
UTAH        A    B     ARIZONA     N    B     COLORADO    A    B      
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    N      
NEBRASKA    A    N     KANSAS      A    B     OKLAHOMA    N    B      
N TEXAS     N    B     S TEXAS     A    B     W TEXAS     A    B      
MINNESOTA   N    B     IOWA        B    N     MISSOURI    B    N      
ARKANSAS    B    B     LOUISIANA   N    N     WISCONSIN   B    B      
ILLINOIS    B    B     MISSISSIPPI N    N     MICHIGAN    B    B      
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    N      
TENNESSEE   B    N     ALABAMA     B    A     NEW YORK    B    B      
VERMONT     B    B     NEW HAMP    B    N     MAINE       B    N      
MASS        B    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    N      
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A      
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  A    B      
AK ALEUTIAN A    B     AK WESTERN  A    B     AK INT BSN  A    B      
AK S INT    A    B     AK SO COAST A    B     AK PNHDL    A    N      
  
                            
 
8-14 DAY OUTLOOK TABLE 
OUTLOOK FOR APR 28 - MAY 04, 2015 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    A     OREGON      N    N     NRN CALIF   N    N      
SRN CALIF   A    N     IDAHO       N    N     NEVADA      N    B      
W MONTANA   N    A     E MONTANA   N    A     WYOMING     A    B      
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B      
NEW MEXICO  A    N     N DAKOTA    N    A     S DAKOTA    A    N      
NEBRASKA    A    B     KANSAS      A    N     OKLAHOMA    B    N      
N TEXAS     B    N     S TEXAS     B    N     W TEXAS     A    A      
MINNESOTA   N    N     IOWA        N    B     MISSOURI    B    B      
ARKANSAS    B    N     LOUISIANA   B    N     WISCONSIN   N    B      
ILLINOIS    B    B     MISSISSIPPI B    N     MICHIGAN    B    B      
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    N      
TENNESSEE   B    N     ALABAMA     B    N     NEW YORK    B    N      
VERMONT     B    N     NEW HAMP    B    N     MAINE       B    N      
MASS        B    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    N      
N CAROLINA  B    N     S CAROLINA  B    N     GEORGIA     B    N      
FL PNHDL    N    A     FL PENIN    A    A     AK N SLOPE  A    N      
AK ALEUTIAN A    B     AK WESTERN  A    B     AK INT BSN  A    B      
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. 
 
$$ 
 

                   
 
Related Topics:
Prognostic Discussion, Surface Forecasts, 500mb Heights and Anomalies, Time Series of Surface Forecast Skill, Model Guidance Used Our Mission, Who We Are, CPC Information, CPC Web Team
 

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