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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: May 11 - 15, 2015 (6-10 Day Outlook)
Valid: May 13 - 19, 2015 (8-14 Day Outlook)
Issued: May 05, 2015

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EDT TUE MAY 05 2015 
 
6-10 DAY OUTLOOK FOR MAY 11 - 15 2015 
 
THE AVAILABLE MODELS EXHIBIT GOOD AGREEMENT ON THE 500-HPA HEIGHT FIELD OVER  
NORTH AMERICA. MOST MODELS DEPICT A TROUGH NEAR THE WEST COAST OF NORTH AMERICA  
THAT EXTENDS OVER THE SOUTHWEST, RIDGING OVER THE CENTRAL PORTIONS OF THE  
CONUS, AND A DEEP TROUGH OVER NORTHEAST CANADA. THAT RESULTS IN A MEAN  
SOUTHERLY COMPONENT TO THE UPPER-LEVEL FLOW OVER THE CONUS. THE MOST APPARENT  
DIFFERENCES IN THE MODEL SOLUTIONS ARE OVER THE GREAT PLAINS WHERE THE  
ECMWF-BASED SOLUTIONS HAVE A SHARPER RIDGE INTO CANADA AND SOME TROUGHING BACK  
OVER THE GREAT LAKES. THE GFS AND ENVIRONMENT CANADA MODELS HAVE INDICATIONS OF  
SHORTWAVE ACTIVITY, BUT ARE HAVE A MORE PROGRESSIVE FLOW.  
 
THE AVERAGE ANALOG CORRELATION FOR THE GFS-BASED SOLUTIONS IS SLIGHTLY HIGHER,  
SO THE 500-HPA MANUAL HEIGHT BLEND IS WEIGHTED SLIGHTLY IN FAVOR OF THE  
GFS-BASED SOLUTIONS. THE MOST WEIGHT IS GIVEN TO THE 0Z GFS ENSEMBLE MEAN AS  
THAT MODEL HAS THE HIGHEST COMBINED ANALOG CORRELATION AND ANOMALY CORRELATION  
SCORE. 
 
THE RESULTANT UPPER-LEVEL PATTERN SUPPORTS ABOVE NORMAL TEMPERATURES OVER  
ALASKA DUE TO MEAN SOUTHERLY FLOW IN THE LOW-LEVELS AND ABOVE NORMAL HEIGHTS  
ALOFT. MEAN SOUTHWESTERLY FLOW EAST OF THE TROUGH NEAR THE WEST COAST, FAVORS  
ABOVE NORMAL TEMPERATURES FOR THE NORTHERN ROCKIES, GREAT BASIN, AND  
CALIFORNIA, EXCEPT ALONG THE IMMEDIATE COAST. BELOW NORMAL TEMPERATURES ARE  
FAVORED OVER THE GREAT PLAINS, SUPPORTED BY THE ENHANCED ODDS OF ABOVE MEDIAN  
PRECIPITATION ACROSS MUCH OF THE SOUTHERN AND CENTRAL GREAT PLAINS AND THE  
POTENTIAL FOR HIGH PRESSURE TO EXTEND SOUTHWARD OUT OF CANADA. MEAN RIDGING  
FAVORS ABOVE NORMAL TEMPERATURES FOR THE EASTERN THIRD OF THE CONUS. 
 
MEAN SOUTHWESTERLY FLOW ALOFT AND EASTERLY FLOW AT LOWER LEVELS, GENERALLY  
FAVORS ABOVE MEDIAN PRECIPITATION FOR MOST OF THE SOUTHERN CONUS. THE POTENTIAL  
FOR HIGH PRESSURE TO EXTEND SOUTHWARD FROM CANADA ENHANCES THE ODDS FOR BELOW  
MEDIAN PRECIPITATION OVER THE NORTHERN GREAT PLAINS. OFFSHORE FLOW INCREASES  
THE ODDS OF BELOW MEDIAN PRECIPITATION FOR THE COASTS OF OREGON AND NORTHERN  
CALIFORNIA. 
 
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS ENSEMBLE MEAN  
CENTERED ON DAY 8, 15% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 10%  
OF TODAY'S OPERATIONAL 0Z GFS 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD  
AGREEMENT AMONG THE MODEL SOLUTIONS, TEMPERED BY DISAGREEMENT AMONG THE SURFACE  
TEMPERATURE AND PRECIPITATION TOOLS. 
 
8-14 DAY OUTLOOK FOR MAY 13 - 19 2015  
 
MODEL SOLUTIONS FOR THE WEEK-2 PERIOD EXHIBIT VERY GOOD AGREEMENT. MOST MODELS  
PREDICT A TROUGH NEAR THE ALEUTIANS, SPLIT FLOW OVER WESTERN NORTH AMERICA WITH  
A TROUGH OVER THE SOUTHWEST, AND GENERALLY ABOVE NORMAL 500-HPA HEIGHTS OVER  
THE EASTERN THIRD OF THE CONUS. OVERALL, THE GFS-BASED SOLUTIONS GENERALLY  
DEPICT HIGHER HEIGHTS OVER THE NORTHERN TIER OF THE CONUS THAN THE ECWMF AND  
ENVIRONMENT CANADA MODEL SOLUTION.  
 
DUE TO THE ABOVE AVERAGE LEVEL OF AGREEMENT, THE 500-HPA MANUAL BLEND IS A  
50/50 WEIGHTING OF GFS-BASED MODELS AND NON GFS-BASED MODELS. THE 6Z GFS  
ENSEMBLE MEAN AND YESTERDAY'S 12Z ECMWF ENSEMBLE MEAN RECEIVE THE MOST WEIGHT  
IN THE MANUAL BLEND, WITH THE 0Z GFS AND CANDIAN ENSEMBLE MEANS FILLING OUT THE  
REMAINDER. 
 
THE RESULTANT UPPER-LEVEL PATTERN FAVORS ABOVE NORMAL TEMPERATURES OVER ALL OF  
ALASKA AND MOST OF THE CONUS, EXCEPT FOR AN AREA CENTERED ON THE SOUTHWEST.  
ABOVE NORMAL 500-HPA HEIGHTS AND LOW LEVEL RIDGING SUPPORT ABOVE NORMAL  
TEMPERATURES EAST OF THE MISSISSIPPI RIVER. NEAR OR BELOW NORMAL TEMPERATURES  
ARE FAVORED FROM CALIFORNIA TO TEXAS, AS FAR NORTH AS CENTRAL UTAH AND COLORADO  
DUE TO A PREDICTED TROUGH OVER THAT REGION. 
 
LOW-LEVEL SOUTHWESTERLY FLOW INCREASES THE ODDS FOR ABOVE MEDIAN PRECIPITATION  
OVER SOUTHWEST ALASKA, WITH BELOW MEDIAN PRECIPITATION OVER THE INTERIOR BASIN  
OF ALASKA. UPPER-LEVEL AND SURFACE RIDGING FAVORS BELOW MEDIAN PRECIPITATION  
FROM THE PACIFIC NORTHWEST TO NORTHERN CALIFORNIA. MEAN SOUTHERLY LOW-LEVEL  
FLOW AND AN UPPER-LEVEL TROUGH FAVOR ABOVE MEDIAN PRECIPITATION FROM THE  
ROCKIES TO THE SOUTHERN GREAT PLAINS AND ACROSS TO THE SOUTHEAST. SURFACE  
RIDGING AND A PROGRESSIVE UPPER-LEVEL FLOW FAVOR BELOW MEDIAN PRECIPITATION  
FROM MISSOURI TO THE GREAT LAKES AND PORTIONS OF THE MID-ATLANTIC. 
 
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 20% OF TODAY'S 0Z GFS ENSEMBLE  
MEAN CENTERED ON DAY 11, 30% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY  
11, 30% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE  
TO VERY GOOD AGREEMENT AMONG THE MODELS BUT TEMPERED BY SMALL DISAGREEMENTS  
AMONG THE TOOLS 
 
FORECASTER: MATT ROSENCRANS 
 
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:  
20040415 - 20090423 - 20040504 - 19540424 - 20000417 
 
 
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:  
20040414 - 20000416 - 20090423 - 19810416 - 20040504 
 
 
6-10 DAY OUTLOOK TABLE 
OUTLOOK FOR MAY 11 - 15 2015 
 
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    A     NEVADA      A    N      
W MONTANA   A    N     E MONTANA   A    B     WYOMING     A    N      
UTAH        A    A     ARIZONA     N    N     COLORADO    B    A      
NEW MEXICO  B    A     N DAKOTA    N    B     S DAKOTA    B    N      
NEBRASKA    B    N     KANSAS      B    N     OKLAHOMA    B    A      
N TEXAS     B    A     S TEXAS     B    A     W TEXAS     B    A      
MINNESOTA   B    N     IOWA        B    N     MISSOURI    N    N      
ARKANSAS    N    A     LOUISIANA   N    A     WISCONSIN   B    N      
ILLINOIS    N    N     MISSISSIPPI N    A     MICHIGAN    N    N      
INDIANA     N    N     OHIO        A    N     KENTUCKY    A    A      
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    N      
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N      
MASS        A    N     CONN        A    N     RHODE IS    A    N      
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    A      
MARYLAND    A    A     DELAWARE    A    A     VIRGINIA    A    A      
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A      
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  A    N      
AK ALEUTIAN A    A     AK WESTERN  A    B     AK INT BSN  A    B      
AK S INT    A    N     AK SO COAST A    N     AK PNHDL    A    N      
  
                            
 
8-14 DAY OUTLOOK TABLE 
OUTLOOK FOR MAY 13 - 19 2015 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N      
SRN CALIF   N    N     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     A    A      
UTAH        A    A     ARIZONA     B    A     COLORADO    A    A      
NEW MEXICO  B    A     N DAKOTA    A    N     S DAKOTA    A    N      
NEBRASKA    A    N     KANSAS      A    N     OKLAHOMA    N    A      
N TEXAS     N    A     S TEXAS     B    A     W TEXAS     B    A      
MINNESOTA   A    N     IOWA        A    N     MISSOURI    A    B      
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   A    N      
ILLINOIS    A    B     MISSISSIPPI A    A     MICHIGAN    A    B      
INDIANA     A    B     OHIO        A    B     KENTUCKY    A    B      
TENNESSEE   A    N     ALABAMA     A    A     NEW YORK    A    N      
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N      
MASS        A    N     CONN        A    N     RHODE IS    A    N      
PENN        A    B     NEW JERSEY  A    B     W VIRGINIA  A    B      
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N      
N CAROLINA  A    A     S CAROLINA  A    A     GEORGIA     A    A      
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  A    N      
AK ALEUTIAN A    A     AK WESTERN  A    N     AK INT BSN  A    B      
AK S INT    A    N     AK SO COAST A    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. 
 
$$ 
 

                   
 
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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