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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 27 - 31, 2015 (6-10 Day Outlook)
Valid: May 29 - Jun 04, 2015 (8-14 Day Outlook)
Issued: May 21, 2015

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EDT THU MAY 21 2015 
 
6-10 DAY OUTLOOK FOR MAY 27 - 31 2015 
 
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA CIRCULATION  
PATTERN OVER NORTH AMERICA. SPLIT-FLOW IS PREDICTED OVER THE WEST COAST OF  
NORTH AMERICA WITH A RIDGE IN THE NORTHERN STREAM OVER WESTERN CANADA AND A  
TROUGH IN THE SOUTHERN STREAM OVER CALIFORNIA AND THE U.S. SOUTHWEST. A TROUGH  
IS PREDICTED OVER CENTRAL AND EASTERN CANADA WHILE ABOVE-NORMAL HEIGHTS ARE  
PREDICTED OVER THE EASTERN U.S. ENSEMBLE SPREAD IS HIGHER OVER THE WEST IN THE  
MODELS WITH UNCERTAINTY IN THE SPLIT FLOW PATTERN. THERE IS GREATER CONSENSUS  
AMONG ENSEMBLE MEMBERS IN PREDICTING THE RIDGE OVER THE EAST. 
 
BELOW NORMAL TEMPERATURES ARE MOST LIKELY IN AN AREA FROM EASTERN ARIZONA TO  
WESTERN TEXAS ASSOCIATED WITH PRECIPITATION AHEAD OF A PREDICTED SOUTHERN  
STREAM TROUGH. THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES  
FOR THE EASTERN U.S., CONSISTENT WITH PREDICTED ABOVE NORMAL HEIGHTS. RIDGING  
OVER WESTERN NORTH AMERICA LEADS TO INCREASED PROBABILITIES OF ABOVE NORMAL  
TEMPERATURES FOR PACIFIC COAST STATES, MONTANA AND ALASKA. 
 
THE TROUGH PREDICTED OVER THE SOUTHWEST AND CONVERGENT FLOW TO THE EAST LEADS  
TO ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR MUCH OF THE CONUS,  
WITH THE GREATEST PROBABILITIES FOR THE LOWER MISSISSIPPI VALLEY. BELOW MEDIAN  
PRECIPITATION IS MORE LIKELY IN COASTAL REGIONS OF THE PACIFIC NORTHWEST AND  
ALONG THE U.S.-CANADIAN BORDER FROM EASTERN MONTANA TO THE WESTERN GREAT LAKES  
REGION UNDER NORTH-WESTERLY FLOW. 
 
THE PROBABILITY OF ABOVE MEDIAN PRECIPITATION IS ENHANCED FOR THE ALEUTIAN  
ISLANDS UNDER A PREDICTED TROUGH, WHILE BELOW MEDIAN PRECIPITATION IS MOST  
LIKELY FOR SOUTHEAST ALASKA INCLUDING THE PANHANDLE, UNDER A PREDICTED RIDGE. 
 
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS ENSEMBLE MEAN  
CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,  
10% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 30% 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  
FAIRLY GOOD AGREEMENT AMONG THE VARIOUS MODELS AND SURFACE TOOLS. 
 
8-14 DAY OUTLOOK FOR MAY 29 - JUN 04, 2015  
 
DURING THE WEEK TWO PERIOD, MODELS SOMEWHAT PERSIST THE CIRCULATION PATTERN OF  
THE 6-10 DAY PERIOD FORECAST, WITH INCREASED UNCERTAINTY AND LARGER ENSEMBLE  
SPREAD IN THE TROUGH AND RIDGE OVER ALASKA. MODELS CONTINUE TO PREDICT TROUGHS  
OVER THE ALEUTIAN ISLANDS, EASTERN CANADA, AND THE U.S. SOUTHWEST, AND RIDGES  
OVER EASTERN ALASKA AND WESTERN CANADA. THE EASTERN HALF OF THE U.S. IS  
FORECAST TO BE UNDER ABOVE NORMAL HEIGHTS WITH RISING HEIGHTS OVER THE CENTRAL  
PLAINS. 
 
ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR THE U.S. WEST, AS WELL AS FOR THE  
EASTERN HALF OF THE CONUS. PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE  
ENHANCED FOR WEST TEXAS, ASSOCIATED WITH THE PREDICTED SOUTHERN STREAM TROUGH.  
ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR ALASKA WITH RIDGING PREDICTED  
OVER WESTERN NORTH AMERICA. 
 
ABOVE MEDIAN PRECIPITATION IS MOST LIKELY OVER MUCH OF THE CONUS ASSOCIATED  
WITH THE SOUTHERN STREAM TROUGH AND CONVERGENCE AHEAD OF THE SPLIT STREAM.  
BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR SOUTHEASTERN ALASKA, AND COASTAL  
AREAS OF THE PACIFIC NORTHWEST, UNDER THE RIDGE OVER THE WEST COAST OF NORTH  
AMERICA. ABOVE MEDIAN PRECIPITATION IS MOST LIKELY FOR THE WEST COAST OF ALASKA  
ASSOCIATED WITH THE TROUGH OVER THE ALEUTIAN ISLANDS. 
 
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 35% OF TODAY'S 6Z GFS ENSEMBLE  
MEAN CENTERED ON DAY 11, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON  
DAY 11, AND 30% 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 GOOD AGREEMENT AMONG MODELS AND TOOLS. 
 
FORECASTER: DAN COLLINS 
 
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  
JUNE 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:  
20080525 - 19980526 - 19660603 - 19710604 - 19580604 
 
 
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:  
20080526 - 19980527 - 20090430 - 19660603 - 19710603 
 
 
6-10 DAY OUTLOOK TABLE 
OUTLOOK FOR MAY 27 - 31 2015 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    A     NRN CALIF   A    N      
SRN CALIF   A    N     IDAHO       A    A     NEVADA      N    A      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     N    A      
UTAH        N    A     ARIZONA     N    N     COLORADO    N    A      
NEW MEXICO  B    A     N DAKOTA    N    B     S DAKOTA    N    A      
NEBRASKA    N    A     KANSAS      N    A     OKLAHOMA    N    A      
N TEXAS     N    A     S TEXAS     N    A     W TEXAS     B    A      
MINNESOTA   N    B     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    A     ALABAMA     A    A     NEW YORK    A    A      
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A      
MASS        A    A     CONN        A    A     RHODE IS    A    A      
PENN        A    A     NEW JERSEY  A    A     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    N     FL PENIN    A    B     AK N SLOPE  A    N      
AK ALEUTIAN A    A     AK WESTERN  A    N     AK INT BSN  A    B      
AK S INT    A    B     AK SO COAST A    B     AK PNHDL    A    B      
  
                            
 
8-14 DAY OUTLOOK TABLE 
OUTLOOK FOR MAY 29 - JUN 04, 2015 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    A     NRN CALIF   A    N      
SRN CALIF   A    N     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     A    A      
UTAH        A    A     ARIZONA     A    N     COLORADO    N    A      
NEW MEXICO  N    A     N DAKOTA    N    N     S DAKOTA    N    A      
NEBRASKA    N    A     KANSAS      N    A     OKLAHOMA    A    A      
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     B    A      
MINNESOTA   N    N     IOWA        A    A     MISSOURI    A    A      
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   N    A      
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A      
INDIANA     A    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    N      
MASS        A    A     CONN        A    A     RHODE IS    A    A      
PENN        A    A     NEW JERSEY  A    A     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    N     AK N SLOPE  A    N      
AK ALEUTIAN A    A     AK WESTERN  A    N     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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