Skip Navigation Links www.nws.noaa.gov 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center
 
 

CPC Search
Graphics & Maps (6-10 Day)
   Surface Fcsts
   500mb Heights
     & Anomalies

   Hawaiian Outlook
     & Anomalies

   Surface Fcst
     Skill

   Model Guidance Used
   Archives [NEW]

Graphics & Maps (8-14 Day)
   Surface Fcsts
   500mb Heights
     & Anomalies

   Model Guidance Used
   Archives [NEW]

Verifications
   Charts
   Explanation

Related Products
   HPC: Day 6, Day 7
   AO/NAO/PNA/AAO

About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

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: Sep 27 - Oct 01, 2021 (6-10 Day Outlook)
Valid: Sep 29 - Oct 05, 2021 (8-14 Day Outlook)
Issued: Sep 21, 2021

Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EDT Tue September 21 2021 
 
6-10 DAY OUTLOOK FOR SEP 27 - OCT 01, 2021 
 
Today's model solutions are in good agreement on the predicted 500-hPa  
circulation pattern across North America and surrounding regions during the  
6-10 day period. Most dynamical model solutions forecast a deep trough over the  
Arctic region stretching from northern Alaska to the Gulf of Alaska. Negative  
500-hPa height anomalies are forecast over most of Mainland Alaska, the Alaska  
Panhandle and parts of the northwestern CONUS, while positive 500-hPa height  
anomalies are favored over the western Aleutians. A broad ridge and associated  
positive 500-hPa height anomalies are predicted over much of the central CONUS.  
A trough is predicted over the eastern CONUS with below normal 500-hPa heights  
anticipated across the East Coast. 
 
Near to above normal temperatures are favored for most of the CONUS due to  
persistent broad ridging and above normal 500-hPa heights over the region and  
also consistent with the consolidation forecast tool. Below normal temperature  
probabilities are elevated over Alaska underneath predicted troughing and below  
normal 500-hPa heights, while above normal temperature probabilities are  
elevated over the western Aleutians, under above normal 500-hPa heights. 
 
Near to above normal precipitation probabilities are enhanced over most of the  
western CONUS due to a forecast trough over the Gulf of Alaska and potential  
storm system development. Below normal precipitation is likely for most of the  
central and eastern CONUS underneath forecast ridging and above normal 500-hPa  
heights. However, a predicted trough over the northeastern CONUS enhances  
probabilities of above normal precipitation over Maine. Troughing and  
associated surface low pressure over the Gulf of Alaska increases the odds of  
above normal precipitation over the Panhandle due to increased southerly flow.  
Near to below normal precipitation probabilities are increased over Mainland  
Alaska due to being farther displaced from the forecast surface low pressure. 
 
The official 6-10 day 500-hPa height blend consists of 40% of Today's 6z GFS  
Ensemble Mean centered on Day 8, 40% of Today's 0z European Ensemble Mean  
centered on Day 8, and 20% 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  
good agreement among the model circulation and temperature forecasts, offset by  
some differences among the precipitation tools. 
 
8-14 DAY OUTLOOK FOR SEP 29 - OCT 05, 2021  
 
Today's ensemble mean dynamical model forecasts are in good agreement on the 
predicted 500-hPa circulation pattern over North America for the week-2 period.  
Anomalous ridging and above normal 500-hPa heights are forecast over the  
western Aleutians, while a trough and below normal 500-hPa heights are  
predicted over Mainland Alaska, the Gulf of Alaska, the Alaska Panhandle and  
parts of the northwestern CONUS. Predicted riding and positive 500-hPa height  
anomalies are forecast over much of CONUS except for the Gulf Coast where weak  
negative height anomalies are indicated. 
 
Anomalous ridging with above normal 500-hPa heights increases chances of above  
normal temperatures over most of the western and central CONUS as well as the  
Northeast. Below normal temperatures are favored over Florida under below  
normal 500-hPa heights. Near normal temperatures are likely over parts of the  
eastern CONUS, consistent with the ERF operational autoblend forecast tool.  
Predicted troughing across Alaska and associated north to northwesterly  
mid-level flow favor increased probabilities of below normal temperatures  
across most of the state. 
  
Near to above normal precipitation probabilities are enhanced over most of the  
western CONUS due to a forecast trough over the Gulf of Alaska. Near to below  
normal precipitation is favored across most of the central and eastern CONUS,  
under the broad ridging and positive 500-hPa heights. The eastward progression  
of the trough over the Gulf of Alaska toward the west coast of British Columbia  
favors increased chances for above normal precipitation across parts of  
southeastern Mainland Alaska and the Panhandle. Near to below normal  
precipitation probabilities are increased for the remainder of the state, on  
the backside of the trough. 
 
The official 8-14 day 500-hPa height blend consists of: 40% of Today's 6z GFS  
Ensemble Mean centered on Day 11, 40% of Today's 0z European Ensemble Mean  
centered on Day 11, and 20% of Today's 0z Canadian Ensemble Mean centered on  
Day 11  
 
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Above average, 4 out of 5, due to  
good agreement among the model circulation and temperature forecasts, offset by  
some differences among the precipitation tools. 
 
FORECASTER: Luke H 
 
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  
October 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:  
19920926 - 19600922 - 19590907 - 19580918 - 20040913 
 
 
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:  
19600921 - 19920924 - 19590906 - 19580917 - 19561001 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Sep 27 - Oct 01, 2021 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    A     OREGON      N    A     NRN CALIF   N    A      
SRN CALIF   N    N     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B      
UTAH        A    A     ARIZONA     A    N     COLORADO    A    N      
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    A    B     KANSAS      A    B     OKLAHOMA    A    B      
N TEXAS     A    B     S TEXAS     A    N     W TEXAS     A    N      
MINNESOTA   A    B     IOWA        A    B     MISSOURI    A    B      
ARKANSAS    A    B     LOUISIANA   A    B     WISCONSIN   A    B      
ILLINOIS    A    B     MISSISSIPPI N    B     MICHIGAN    A    B      
INDIANA     N    B     OHIO        N    B     KENTUCKY    N    B      
TENNESSEE   N    B     ALABAMA     N    B     NEW YORK    N    N      
VERMONT     N    N     NEW HAMP    N    N     MAINE       A    A      
MASS        N    N     CONN        N    N     RHODE IS    N    N      
PENN        N    B     NEW JERSEY  N    N     W VIRGINIA  N    B      
MARYLAND    N    B     DELAWARE    N    B     VIRGINIA    N    B      
N CAROLINA  N    B     S CAROLINA  N    B     GEORGIA     N    B      
FL PNHDL    N    B     FL PENIN    N    N     AK N SLOPE  B    N      
AK ALEUTIAN B    N     AK WESTERN  B    N     AK INT BSN  B    B      
AK S INT    B    B     AK SO COAST B    B     AK PNHDL    B    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Sep 29 - Oct 05, 2021 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    A     OREGON      N    A     NRN CALIF   A    A      
SRN CALIF   A    N     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B      
UTAH        A    A     ARIZONA     A    N     COLORADO    A    N      
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    A    B     KANSAS      A    B     OKLAHOMA    A    B      
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    N      
MINNESOTA   A    B     IOWA        A    B     MISSOURI    A    B      
ARKANSAS    A    B     LOUISIANA   A    B     WISCONSIN   A    B      
ILLINOIS    A    B     MISSISSIPPI N    B     MICHIGAN    A    B      
INDIANA     A    B     OHIO        N    B     KENTUCKY    N    B      
TENNESSEE   N    B     ALABAMA     N    B     NEW YORK    N    B      
VERMONT     A    B     NEW HAMP    A    B     MAINE       A    B      
MASS        A    N     CONN        A    N     RHODE IS    A    N      
PENN        N    B     NEW JERSEY  N    B     W VIRGINIA  N    B      
MARYLAND    N    B     DELAWARE    N    B     VIRGINIA    N    B      
N CAROLINA  N    B     S CAROLINA  N    B     GEORGIA     N    B      
FL PNHDL    N    N     FL PENIN    B    A     AK N SLOPE  B    N      
AK ALEUTIAN B    N     AK WESTERN  B    N     AK INT BSN  B    N      
AK S INT    B    N     AK SO COAST B    N     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
 

NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740
Climate Prediction Center Web Team
Page last modified: July 21, 2014
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act
About Us
Careers