Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussions

Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EDT Wed October 16 2019 
 
6-10 DAY OUTLOOK FOR OCT 22 - 26 2019 
 
Today's model forecasts are in good agreement in terms of the mid-level  
circulation pattern for the 6-10 day period. Ensemble means from the ECMWF,  
GEFS, and Canadian models predict troughs over the Aleutian Islands and the  
north-central CONUS, and a ridge over the Pacific coast of North America.  
Spaghetti diagrams of the 500-hPa heights indicate relatively large ensemble  
spread and low confidence in an amplified ridge over the North Atlantic. The  
official blended 500-hPa height pattern indicates negative 500-hPa height  
anomalies over the Aleutian Islands and over the north-central CONUS and  
positive 500-hPa height anomalies to the west of the Rocky Mountains and along  
the Eastern Seaboard.  
 
Probabilities are enhanced for below normal temperatures across much of the  
eastern Rocky Mountains and central CONUS under predicted negative 500-hPa  
height anomalies, while above normal temperatures are likely over the western  
CONUS, under above normal 500-hPa heights. Enhanced probabilities for above  
normal temperatures are also indicated for parts of the eastern CONUS, under  
southerly flow ahead of the trough and in association with near to above normal  
500-hPa heights. Above normal temperatures are likely for southern and western  
Alaska, associated with above average sea surface temperatures.  
 
Amplified troughing over the north-central CONUS leads to elevated  
probabilities of above normal precipitation over the entire eastern CONUS, with  
the highest probabilities exceeding 60 percent in the Southeast region,  
supported by the consolidation forecast tool. Above normal precipitation is  
also likely from Washington state eastward across the Northern Plains, as  
indicated by the GEFS and ECMWF reforecast tools. Above normal precipitation is  
likely for southern areas of Alaska including the Panhandle, ahead of a  
predicted trough, while below normal precipitation is likely for northwestern  
Alaska. 
 
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, between the models on the predicted 500-hPa height pattern, and  
among the temperature and precipitation forecast tools. 
 
8-14 DAY OUTLOOK FOR OCT 24 - 30 2019  
 
The GEFS, ECMWF and Canadian ensemble means for the 8-14 day forecast period  
indicate continued eastward progression of the circulation pattern over North  
America. Models predict trough axes over western areas of Alaska and over the  
Upper Mississippi Valley and Great Lakes in the week 2 period, with a ridge  
predicted to be near the Pacific Coast of North America in the ensemble mean  
forecasts. The official 500-hPa model height blend indicates negative 500-hPa  
height anomalies to the south of the Aleutian Islands, as well as over much of  
the eastern half of the CONUS. Positive 500-hPa height anomalies are forecast  
over eastern Alaska and over the western CONUS.  
 
The predicted temperature pattern for the week 2 period reflects the predicted  
eastward progression of the circulation pattern from the 6-10 day period. Below  
normal temperatures are likely from the Rockies eastward to the Mid-Atlantic  
and parts of the Southeast, under the predicted 500-hPa trough. Near to above  
normal temperatures are more likely over the southern Florida Peninsula and  
parts of the Northeast, consistent with the consolidation forecast tool.  
Probabilities of above normal temperatures continue to be enhanced for most  
areas west of the Rocky Mountains, associated with predicted positive 500-hPa  
height anomalies. Above normal temperatures are likely for southern and western  
Alaska in the week 2 period, under predicted above normal 500-hPa heights over  
the region and above normal sea surface temperatures nearby. 
 
With the predicted eastward progression of the trough over the CONUS in the  
week 2 period, the area of likely above normal precipitation extends across  
parts of the Northern Plains and the northern Great Lakes region and southward  
along the Atlantic Coast to the Florida Peninsula. Below normal precipitation  
is likely for remaining areas of the CONUS, from the Pacific Northwest and the  
Southwest eastward across the Central and Southern Plains into the Middle and  
Lower Mississippi Valley, and parts of the Southeast and the Tennessee Valley.  
Above normal precipitation is likely for most areas of Alaska, excluding the  
northwestern mainland, ahead of the predicted trough over the Aleutian Islands.  
 
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 between models on the predicted 500-hPa height pattern, offset  
by uncertainty related to the evolution of the pattern later in week-2. 
 
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  
October 17. 
 
 
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:  
19941022 - 19951008 - 20071011 - 20011024 - 20051023 
 
 
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:  
19941022 - 19681005 - 19951007 - 20051021 - 20071011 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Oct 22 - 26 2019 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    A     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    N     IDAHO       B    B     NEVADA      A    B      
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A      
UTAH        N    B     ARIZONA     A    B     COLORADO    B    B      
NEW MEXICO  N    B     N DAKOTA    B    A     S DAKOTA    B    A      
NEBRASKA    B    B     KANSAS      B    B     OKLAHOMA    B    B      
N TEXAS     B    B     S TEXAS     B    B     W TEXAS     B    B      
MINNESOTA   B    A     IOWA        B    N     MISSOURI    B    N      
ARKANSAS    B    N     LOUISIANA   B    A     WISCONSIN   B    A      
ILLINOIS    B    A     MISSISSIPPI B    A     MICHIGAN    N    A      
INDIANA     N    A     OHIO        N    A     KENTUCKY    N    A      
TENNESSEE   B    A     ALABAMA     N    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    A     FL PENIN    A    A     AK N SLOPE  N    N      
AK ALEUTIAN A    A     AK WESTERN  A    B     AK INT BSN  N    N      
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Oct 24 - 30 2019 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    N     IDAHO       B    B     NEVADA      A    B      
W MONTANA   B    B     E MONTANA   B    N     WYOMING     B    N      
UTAH        A    B     ARIZONA     A    B     COLORADO    B    B      
NEW MEXICO  N    B     N DAKOTA    B    N     S DAKOTA    B    N      
NEBRASKA    B    B     KANSAS      B    B     OKLAHOMA    B    B      
N TEXAS     B    B     S TEXAS     B    B     W TEXAS     B    B      
MINNESOTA   B    N     IOWA        B    B     MISSOURI    B    B      
ARKANSAS    B    B     LOUISIANA   B    B     WISCONSIN   B    B      
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    B    N      
INDIANA     B    B     OHIO        B    N     KENTUCKY    B    B      
TENNESSEE   B    B     ALABAMA     B    B     NEW YORK    N    A      
VERMONT     N    A     NEW HAMP    A    A     MAINE       A    A      
MASS        A    A     CONN        A    A     RHODE IS    A    A      
PENN        B    A     NEW JERSEY  N    A     W VIRGINIA  B    A      
MARYLAND    N    A     DELAWARE    N    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  N    A      
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  N    A      
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    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. 
 
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