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: Aug 18 - 22, 2020 (6-10 Day Outlook)
Valid: Aug 20 - 26, 2020 (8-14 Day Outlook)
Issued: Aug 12, 2020

Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EDT Wed August 12 2020 
 
6-10 DAY OUTLOOK FOR AUG 18 - 22 2020 
 
Today's 6-10 day 500-hPa outlook features anomalous ridging over the Bering Sea  
and over the western half of the CONUS. A deep anomalous trough is predicted  
over the Gulf of Alaska. Over the eastern U.S. a trough is forecast, but models  
disagree on the intensity. Today's deterministic GFS runs and GFS ensemble">GFS ensemble  
means predict a deeper trough than today's 0z ECMWF ensemble. Because the 0z  
ECMWF ensemble has shown higher skill at 500-hPa over the past 2 months, and  
because CPC's recent calibrated ECMWF ensemble forecasts have consistently  
shown higher skill for 2m temperature and precipitation, the 0z ECMWF ensemble  
mean was favored in today's manual 500-hPa blend, which features relatively  
weak negative 500-hPa height anomalies over the eastern CONUS. 
 
Anomalous ridging over the Bering Sea favors near to above normal temperatures  
over most of Alaska. The western half of the CONUS is expected to remain under  
the influence of 500-hPa ridging and positive height anomalies, enhancing  
chances of above normal temperatures. The greatest probabilities of above  
normal temperatures are over the Great Basin , which is directly beneath the  
maximum positive height anomalies and is likely to experience persistent above  
normal temperatures. The lowest probabilities are in the Pacific Northwest, due  
to the offshore trough forecast to move onshore towards the end of the 6-10 day  
period. Intrusion of relatively cold Canadian air is forecast to lower  
temperatures across much of the eastern half of the CONUS during the period.  
This favors below normal temperatures for much of the eastern CONUS. Above  
normal temperatures are favored over parts of New England as ridging is  
forecast to build toward the end of the period, as well as for the Florida  
peninsula, which is expected to remain south of the forecast surface front. 
 
Below normal precipitation is favored for most of Alaska due to forecast  
ridging over the Bering Sea. A deep trough expected over the eastern Gulf of  
Alaska increases chances of above normal precipitation over the Alaska  
Panhandle and parts of the Pacific Northwest. Beneath and downstream of the  
ridge axis over the western CONUS, below normal precipitation is favored from  
near the Continental Divide eastward through most of the Great Plains, to parts  
of the Northeast. Enhanced probabilties of above normal precipitation are  
favored for southern California, as a shift in the mean surface high position  
and potential tropical activity in the eastern Pacific may promote increased  
moisture flow into the region. Enhanced rainfall near a predicted surface  
trough increases the chances of above normal precipitation for parts of  
Southern Texas, the Southeast and Mid-Atlantic coasts. 
 
The official 6-10 day 500-hPa height blend consists of 15% of Today's 6z GFS  
Ensemble Mean centered on Day 8, 15% of Today's GFS Superensemble 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 Today's operational 0z  
ECMWF 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 models for most of the forecast domain and fairly good  
agreement among the temperature and precipitation tools. 
 
8-14 DAY OUTLOOK FOR AUG 20 - 26 2020  
 
During the week-2 period, the 500-hPa pattern from the Bering Sea east to the  
western CONUS is forecast to be very similar to the 6-10 day period, except  
lower in amplitude due to an increase in spread among ensemble members. Across  
the eastern CONUS there continues to be larger uncertainty with respect to the  
strength of a 500-hPa trough. Today's 0z ECMWF and Canadian ensemble means  
predict a weaker trough than today's GFS ensemble">GFS ensemble means. 
 
Above normal temperatures are favored for Mainland Alaska and the Aleutians,  
underneath forecast above normal 500 hPa heights. With a forecast ridge over  
much of the western half of the CONUS, above normal temperatures are favored  
there. Large negative temperature anomalies associated with the trough  
predicted over parts of the eastern CONUS during the first half of the week-2  
period support increased chances of below normal temperatures from parts of the  
Southern Plains to the Southeast. However, a return to southerly flow predicted  
in the second half of the period enhances the likelihood of above normal  
temperatures from the Northern Plains to the Northeast and parts of  
Mid-Atlantic. The Florida Peninsula is expected to remain south of the surface  
front, favoring above normal temperatures there. 
 
The precipitation outlook for the week-2 period is very similar to the 6-10 day  
period. Probabilities are a bit lower, though, due to an increase in  
uncertainty due to a more transient pattern expected to develop. The GEFS  
reforecast tool (wetter) and ECMWF reforecast tool (drier) continue to differ  
across the Desert Southwest. If a northward surge of enhanced moisture,  
associated with tropical cyclones in the East Pacific, then monsoon rainfall  
may begin to increase. 
 
The official 8-14 day 500-hPa height blend consists of: 15% of Today's 6z GFS  
Ensemble Mean centered on Day 11, 15% of Today's GFS Superensemble Mean  
centered on Day 11, 10% of Today's operational 6z GFS 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 models for much of the forecast domain and fairly  
agreement among the temperature and precipitation tools. 
 
FORECASTER: Y. Fan 
 
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  
August 20. 
 
 
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:  
19950811 - 19850807 - 19700817 - 19620823 - 20060804 
 
 
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:  
19850808 - 19620823 - 19950812 - 19640726 - 19950803 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Aug 18 - 22 2020 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N      
SRN CALIF   A    A     IDAHO       A    B     NEVADA      A    N      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B      
UTAH        A    B     ARIZONA     A    N     COLORADO    A    B      
NEW MEXICO  A    B     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    B    B     KANSAS      B    B     OKLAHOMA    B    B      
N TEXAS     B    B     S TEXAS     N    N     W TEXAS     N    B      
MINNESOTA   B    B     IOWA        B    B     MISSOURI    B    B      
ARKANSAS    B    B     LOUISIANA   B    B     WISCONSIN   B    B      
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    B    B      
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    B      
TENNESSEE   B    B     ALABAMA     B    A     NEW YORK    B    B      
VERMONT     N    B     NEW HAMP    N    B     MAINE       N    B      
MASS        N    B     CONN        N    B     RHODE IS    N    B      
PENN        B    N     NEW JERSEY  B    N     W VIRGINIA  B    N      
MARYLAND    B    A     DELAWARE    B    A     VIRGINIA    B    A      
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A      
FL PNHDL    B    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    N    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Aug 20 - 26 2020 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    A     OREGON      A    N     NRN CALIF   A    N      
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B      
UTAH        A    B     ARIZONA     A    N     COLORADO    A    B      
NEW MEXICO  A    B     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    A    B     KANSAS      N    B     OKLAHOMA    B    B      
N TEXAS     B    B     S TEXAS     B    A     W TEXAS     A    B      
MINNESOTA   A    B     IOWA        N    B     MISSOURI    B    B      
ARKANSAS    B    B     LOUISIANA   B    N     WISCONSIN   A    B      
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    A    B      
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    B      
TENNESSEE   B    N     ALABAMA     B    N     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        N    N     NEW JERSEY  A    N     W VIRGINIA  B    N      
MARYLAND    N    N     DELAWARE    A    N     VIRGINIA    B    A      
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A      
FL PNHDL    N    A     FL PENIN    A    N     AK N SLOPE  A    B      
AK ALEUTIAN A    N     AK WESTERN  A    N     AK INT BSN  A    B      
AK S INT    A    B     AK SO COAST A    B     AK PNHDL    N    B      
  
                           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