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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: Aug 23 - 27, 2017 (6-10 Day Outlook)
Valid: Aug 25 - 31, 2017 (8-14 Day Outlook)
Issued: Aug 17, 2017

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EDT THU AUGUST 17 2017 
 
6-10 DAY OUTLOOK FOR AUG 23 - 27 2017 
 
TODAY'S ENSEMBLE MEAN FORECASTS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED  
MID-TROPOSPHERIC FLOW PATTERN FOR NORTH AMERICA. TROUGHS ARE ANTICIPATED OVER  
THE NORTHEASTERN AND NORTHWESTERN LOWER 48 STATES AND ALASKA, WHILE A RIDGE IS  
EXPECTED OVER THE WEST-CENTRAL CONUS. THE DETERMINISTIC SOLUTIONS FROM THE GFS  
AND ECMWF ARE IN BASICALLY GOOD AGREEMENT WITH THE ENSEMBLE MEAN FORECASTS,  
EXCEPT AS IS TYPICALLY THE CASE, THEY ARE MORE AMPLIFIED WITH THE MAIN  
CIRCULATION FEATURES. THE ENSEMBLE SPAGHETTI CHARTS GENERALLY INDICATE LOW  
SPREAD OVER THE EASTERN CONUS, AND MODERATE SPREAD OVER THE WESTERN CONUS AND  
EASTERN PACIFIC. TODAY'S 500-HPA BLEND CHART INDICATES NEAR TO ABOVE NORMAL  
HEIGHTS OVER THE NORTHWESTERN AND NORTH-CENTRAL CONUS, AND CENTRAL AND NORTHERN  
MAINLAND ALASKA, WHILE NEAR TO BELOW NORMAL HEIGHTS ARE ANTICIPATED OVER THE  
REMAINDER OF THE FORECAST DOMAIN. 
 
BELOW NORMAL HEIGHTS TILT THE ODDS TO BELOW NORMAL TEMPERATURES FOR MUCH OF THE  
NORTHEASTERN U.S., WHILE ABOVE NORMAL HEIGHTS FAVOR ABOVE NORMAL TEMPERATURES  
FOR MUCH OF THE NORTHWESTERN CONUS. THE EXPECTATION OF NEAR NORMAL HEIGHTS AND  
ABOVE NORMAL TEMPERATURES EARLY IN THE PERIOD ENHANCES PROBABILITIES FOR ABOVE  
NORMAL TEMPERATURES FOR MUCH OF THE SOUTHERN TIER OF THE CONUS. THE TROUGH  
FORECAST OVER ALASKA TILTS THE ODDS TO BELOW NORMAL TEMPERATURES FOR THE  
WESTERN PART OF THE STATE, WHILE ABOVE NORMAL SEA SURFACE TEMPERATURES ENHANCE  
PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR THE WESTERN ALEUTIANS. 
 
ANOMALOUS NORTHWESTERLY FLOW TILTS THE ODDS TO BELOW NORMAL PRECIPITATION NEAR  
THE GREAT LAKES AND PARTS OF THE OHIO VALLEY. A FRONTAL SYSTEM AND THE  
POSSIBILITY OF TROPICAL MOISTURE ENHANCE PROBABILITIES FOR ABOVE NORMAL  
PRECIPITATION FOR FLORIDA AND PARTS OF THE SOUTHEAST. THE TROUGH FORECAST OVER  
THE NORTHEAST FAVORS ABOVE NORMAL PRECIPITATION FOR MAINE. MONSOONAL MOISTURE  
AND THE LIKELIHOOD OF MCS ACTIVITY TILT THE ODDS TO ABOVE NORMAL PRECIPITATION  
FOR PARTS OF THE WEST-CENTRAL CONUS. A TROUGH EXPECTED OVER THE NORTHWEST U.S.  
ENHANCES PROBABILITIES FOR ABOVE NORMAL PRECIPITATION FOR PARTS OF THE INTERIOR  
NORTHWESTERN U.S. ANOMALOUS NORTHEASTERLY FLOW FAVORS BELOW NORMAL  
PRECIPITATION FOR PARTS OF NORTHWESTERN MAINLAND ALASKA, WHILE THE TROUGH  
EXPECTED OVER ALASKA TILT THE ODDS TO ABOVE NORMAL PRECIPITATION FOR  
SOUTHEASTERN MAINLAND ALASKA AND THE ALASKA PANHANDLE. 
  
 
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 20% OF TODAY'S 0Z GFS ENSEMBLE MEAN  
CENTERED ON DAY 8, 10% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 10%  
OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 7, 10% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND  
10% OF YESTERDAY'S 12Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 7  
  
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
FAIRLY GOOD MODEL AGREEMENT, WITH SOME DISAGREEMENT AMONG THE FORECAST TOOLS 
 
8-14 DAY OUTLOOK FOR AUG 25 - 31 2017  
 
DURING THE WEEK-2 PERIOD, A LESS AMPLIFIED PATTERN IS EXPECTED. THE TROUGH OVER  
THE NORTHEASTERN CONUS IS FORECAST TO PROGRESS NORTHEASTWARD AND WEAKEN AS THE  
NORTHERN PART OF THE RIDGE OVER THE WEST-CENTRAL U.S. GETS FLATTENED BY TROUGH  
ENERGY PROGRESSING EASTWARD FROM THE NORTHWESTERN CONUS. TROUGHING IS  
ANTICIPATED TO PERSIST OVER MUCH OF WESTERN AND CENTRAL MAINLAND ALASKA. THE  
ENSEMBLE SPAGHETTI CHARTS INDICATE MODERATE TO LARGE SPREAD ACROSS MOST OF THE  
FORECAST DOMAIN. TODAY'S 500-HPA BLEND CHART INDICATES NEAR TO ABOVE NORMAL  
HEIGHTS OVER THE NORTHWESTERN HALF OF THE CONUS AND MOST OF ALASKA, WHILE NEAR  
TO BELOW NORMAL HEIGHTS ARE ANTICIPATED OVER THE SOUTHEASTERN HALF OF THE CONUS  
AND OVER EXTREME SOUTHWESTERN MAINLAND ALASKA AND THE ALASKA PENINSULA. 
 
THE TEMPERATURE PROBABILITY FORECAST DURING THE WEEK-2 PERIOD IS SIMILAR TO THE  
6-10 DAY PERIOD, WITH A COUPLE OF EXCEPTIONS. AS SURFACE HIGH PRESSURE BUILDS  
SOUTHEASTWARD DURING WEEK 2, A SOMEWHAT COOLER PATTERN IS EXPECTED ALONG MUCH  
OF THE GULF COAST, WHILE AS MID-LEVEL HEIGHTS RISE OVER THE SOUTHWEST U.S. A  
WARMER REGIME IS ANTICIPATED FOR SOUTHERN CALIFORNIA AND PARTS OF NORTHERN  
ARIZONA. 
 
RISING HEIGHTS OVER THE NORTHWESTERN CONUS LEADS TO ENHANCED PROBABILITIES FOR  
BELOW NORMAL PRECIPITATION FOR THE REGION. RESIDUAL MONSOONAL MOISTURE, IN  
COMBINATION WITH POSSIBLE MCS ACTIVITY TILT THE ODDS TO ABOVE NORMAL  
PRECIPITATION FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS. ABOVE NORMAL  
PRECIPITATION IS ALSO ANTICIPATED FOR FLORIDA AS A FRONT DISSIPATES OVER THE  
REGION AND TROPICAL WAVES APPROACH FROM THE TROPICAL ATLANTIC. ABOVE NORMAL  
HEIGHTS TILT THE ODDS TO BELOW NORMAL PRECIPITATION FOR NORTHERN MAINLAND  
ALASKA, WHILE ANOMALOUS SOUTHWESTERLY FLOW LEADS TO ENHANCED PROBABILITIES FOR  
ABOVE NORMAL PRECIPITATION FOR THE SOUTHEASTERN MAINLAND ALASKA AND THE ALASKA  
PANHANDLE. 
 
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 25% OF TODAY'S 0Z GFS ENSEMBLE  
MEAN CENTERED ON DAY 11, 5% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11,  
25% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 5% OF TODAY'S  
OPERATIONAL 0Z GFS CENTERED ON DAY 11, 25% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 11, 5% 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: ABOUT AVERAGE, 3 OUT OF 5, DUE  
TO FAIRLY GOOD MODEL AGREEMENT, WITH SOME DISAGREEMENT AMONG THE TEMPERATURE  
TOOLS 
 
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  
SEPTEMBER 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: 19800814 - 19690817 - 19910802 - 19640818 - 19660812
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: 19660810 - 19800813 - 19640817 - 19690816 - 19660816 6-10 DAY OUTLOOK TABLE OUTLOOK FOR AUG 23 - 27 2017 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON A A NRN CALIF A N SRN CALIF N N IDAHO A A NEVADA A N W MONTANA A A E MONTANA A N WYOMING A N UTAH N N ARIZONA N N COLORADO N A NEW MEXICO A A N DAKOTA N N S DAKOTA N N NEBRASKA B A KANSAS N A OKLAHOMA N A N TEXAS A N S TEXAS A N W TEXAS A A MINNESOTA B B IOWA B N MISSOURI B A ARKANSAS N A LOUISIANA A N WISCONSIN B B ILLINOIS B N MISSISSIPPI N N MICHIGAN B B INDIANA B B OHIO B B KENTUCKY B B TENNESSEE B N ALABAMA N N NEW YORK B N VERMONT B N NEW HAMP B A MAINE N A MASS B A CONN B N RHODE IS B N PENN B B NEW JERSEY B N W VIRGINIA B B MARYLAND B B DELAWARE B N VIRGINIA B N N CAROLINA B N S CAROLINA N N GEORGIA A N FL PNHDL A A FL PENIN A A AK N SLOPE N B AK ALEUTIAN N N AK WESTERN B B AK INT BSN N N AK S INT B N AK SO COAST B A AK PNHDL B A 8-14 DAY OUTLOOK TABLE OUTLOOK FOR AUG 25 - 31 2017 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A N SRN CALIF A N IDAHO A B NEVADA A N W MONTANA A B E MONTANA A N WYOMING A N UTAH A N ARIZONA A N COLORADO N A NEW MEXICO A A N DAKOTA N N S DAKOTA N N NEBRASKA N N KANSAS B A OKLAHOMA B A N TEXAS N A S TEXAS A A W TEXAS N A MINNESOTA N N IOWA B N MISSOURI B N ARKANSAS B N LOUISIANA N A WISCONSIN B B ILLINOIS B N MISSISSIPPI N N MICHIGAN B B INDIANA B B OHIO B B KENTUCKY B N TENNESSEE B N ALABAMA B N NEW YORK B B VERMONT B B NEW HAMP B B MAINE B B MASS B B CONN B B RHODE IS B B PENN B B NEW JERSEY B B W VIRGINIA B B MARYLAND B B DELAWARE B B VIRGINIA B B N CAROLINA B N S CAROLINA B N GEORGIA N N FL PNHDL N A FL PENIN A A AK N SLOPE N B AK ALEUTIAN N N AK WESTERN B B AK INT BSN N N AK S INT B N AK SO COAST B A AK PNHDL B 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. $$
 
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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