Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EST Tue November 12 2019 
 
6-10 DAY OUTLOOK FOR NOV 18 - 22 2019 
 
There remains decent model agreement regarding a transient 500-hPa geopotential  
height pattern in the 6-10 day period. The last several runs of the  
deterministic GFS are out of phase with its ensembles and therefore were  
omitted from today's manual blend. Guidance depicts an amplified trough over  
the East early in the period, with more troughing developing over the the West  
later in the period. The ECMWF and Canadian ensembles maintain the strong  
ridging over the Northeast Pacific, with the GEFS trending slightly stronger  
with this ridging as well. A stronger ridge would result in a potential for a  
more elongated trough axis over the West, or potentially a cut-off mid-level  
low developing near or off the Southern California Coast. Today's forecast  
gives most weight to the ECMWF ensembles due to their good continuity with  
previous forecasts. The manual blend shows above normal 500-hPa heights for the  
northwest quadrant of the CONUS, near normal heights for the Southwest,  
Central, and southeastern CONUS, and above normal heights over the Northeast.  
Troughing forecast over western Alaska and the Bering Sea favors below normal  
heights across the state and a continued active storm track. 
 
Increased above normal temperature probabilities are favored for the western  
half of the CONUS. Ridging in the Northeast Pacific favors an inland expansion  
of positive height anomalies resulting in the warmer temperatures. While  
troughing and resultant cooler temperatures may build into the West later in  
the period, both the GEFS and ECWMF reforecast tools, as well as the  
consolidation tool, depict increased above normal temperature probabilities  
which are favored in today's forecast. East of the Mississippi, initial  
troughing favors some below normal temperatures, but a trend toward warmer  
temperatures is favored as that trough weakens. For the entire period,  
increased below normal temperature probabilities are favored for parts of the  
Lower Mississippi Valley and the Southeast, with enhanced near normal  
temperature probabilities forecast for the remainder of the East. Increased  
above normal temperature probabilities are forecast for Alaska due to continued  
southerly flow combined with anomalously warm sea surface temperatures. 
 
A series of low pressure systems is forecast to impact Alaska throughout the  
period favoring enhanced probabilities of above normal precipitation.  
Underneath ridging and the positive height anomalies over the West, anomalously  
dry conditions are favored to continue. Downstream, the potential for shortwave  
troughing to amplify along with lee side cyclogenesis favor above normal  
precipitation for the Southwest, Rockies, Great Plains, and parts of the Upper  
and Middle Mississippi Valley. There is a bit more uncertainty to the east  
where low pressure is forecast to track off the East Coast early in the period.  
The ECMWF ensembles now track the system closer to the coast than the GEFS. The  
GEFS therefore shows less precipitation. Because more weight is being given to  
the ECMWF in this forecast, increased probabilities of above normal  
precipitation is favored for coastal parts of the Northeast due to the  
possibility of enhanced moisture flow off of the Atlantic. Increased below  
normal precipitation probabilities are forecast over the Tennessee Valley,  
Lower Mississippi Valley, and the Southeast, which are forecast to be displaced  
far enough from the aforementioned low pressure, and on the back side of a  
weakening trough axis. 
 
The official 6-10 day 500-hPa height blend consists of 20% of Today's 6z GFS  
Ensemble Mean centered on Day 8, 50% of Today's 0z European Ensemble Mean  
centered on Day 8, 5% of Today's operational 0z ECMWF centered on Day 8, and  
25% of Today's 0z Canadian Ensemble Mean centered on Day 8  
  
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Average, 3 out of 5, due to model  
agreement in terms of the pattern, offset by timing and spatial differences in  
regards to the evolution of the overall pattern later in the period. 
 
8-14 DAY OUTLOOK FOR NOV 20 - 26 2019  
 
A generally low amplitude 500-hPa geopotential height pattern reduces  
confidence in the week-2 outlook. The largest uncertainty is over the West,  
where the ECMWF and Canadian maintain strong ridging in the Northeast Pacific  
throughout week-2. Conversely, the GEFS weakens this ridging faster. Only the  
ECMWF and Canadain were considered in today's week-2 outlook due to their  
agreement on the mid-level height pattern. The manual blend for week-2 shows  
above normal heights for the northwestern CONUS, with near normal heights  
elsewhere throughout the CONUS. Above normal heights are also favored for the  
Alaska Panhandle and extreme eastern mainland Alaska. Below normal heights  
remain favored for western mainland Alaska and the Aleutians. 
 
Slightly enhanced near to above normal temperature probabilities are posted  
throughout much of the CONUS due to the lack of any substantial signal for  
cooler temperatures. There has been a cooling trend in the guidance over the  
West due to the potential for more troughing to develop. However, given the  
forecast for the ridging and positive height anomalies to remain over the  
Northwest, above normal temperatures are favored for that region. Below normal  
temperature probabilities are increased over the Desert Southwest and the  
Southern and Central Rockies, closer to the potential trough axis. 
 
Amplifying shortwave troughing over the Rockies and Desert Southwest favors  
enhanced chances for above normal precipitation in those areas. Above normal  
precipitation probabilities are also increased over Southern California where a  
potential cut-off mid level low may increase moisture throughout the area.  
Surface low pressure ejecting out of the Rockies may result in elevated  
precipitation chances across the Plains and Mississippi Valley. Below normal  
precipitation remains favored for much of the northwestern CONUS under the  
influence of ridging. Below normal precipitation is favored for parts of the  
Northeast and Mid-Atlantic, consistent with the ECMWF reforecast tool.  
Increased probabilities for above normal precipitation remain favored for  
Alaska due to persistent cyclonic flow. 
 
The official 8-14 day 500-hPa height blend consists of: 80% 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: Below average, 2 out of 5, due to  
a forecast low amplitude pattern with lack of defined mid-level features over  
much of the CONUS. 
 
FORECASTER: Thomas Collow 
 
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  
November 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:  
19931026 - 19511029 - 19571122 - 19761126 - 19861101 
 
 
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:  
19931025 - 19511029 - 19641120 - 19581125 - 19861101 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Nov 18 - 22 2019 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    A     IDAHO       A    B     NEVADA      A    B      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     A    A      
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A      
NEW MEXICO  A    A     N DAKOTA    A    A     S DAKOTA    A    A      
NEBRASKA    A    A     KANSAS      A    A     OKLAHOMA    A    A      
N TEXAS     N    A     S TEXAS     N    A     W TEXAS     A    A      
MINNESOTA   A    A     IOWA        N    A     MISSOURI    N    A      
ARKANSAS    N    A     LOUISIANA   N    B     WISCONSIN   A    A      
ILLINOIS    N    A     MISSISSIPPI B    B     MICHIGAN    N    A      
INDIANA     N    N     OHIO        N    N     KENTUCKY    N    B      
TENNESSEE   N    B     ALABAMA     N    B     NEW YORK    N    N      
VERMONT     N    N     NEW HAMP    N    A     MAINE       N    A      
MASS        N    A     CONN        N    A     RHODE IS    N    A      
PENN        N    N     NEW JERSEY  N    N     W VIRGINIA  N    B      
MARYLAND    N    N     DELAWARE    N    A     VIRGINIA    N    N      
N CAROLINA  N    N     S CAROLINA  B    B     GEORGIA     B    B      
FL PNHDL    N    B     FL PENIN    N    N     AK N SLOPE  A    A      
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    A      
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Nov 20 - 26 2019 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    A     IDAHO       A    B     NEVADA      N    B      
W MONTANA   A    B     E MONTANA   A    A     WYOMING     N    A      
UTAH        B    A     ARIZONA     B    A     COLORADO    B    A      
NEW MEXICO  B    A     N DAKOTA    A    A     S DAKOTA    A    A      
NEBRASKA    N    A     KANSAS      N    A     OKLAHOMA    N    A      
N TEXAS     N    A     S TEXAS     N    A     W TEXAS     N    A      
MINNESOTA   A    A     IOWA        N    A     MISSOURI    N    A      
ARKANSAS    N    A     LOUISIANA   N    A     WISCONSIN   N    A      
ILLINOIS    N    A     MISSISSIPPI N    A     MICHIGAN    N    N      
INDIANA     N    N     OHIO        A    N     KENTUCKY    N    A      
TENNESSEE   A    N     ALABAMA     A    N     NEW YORK    A    N      
VERMONT     A    B     NEW HAMP    A    B     MAINE       A    N      
MASS        A    B     CONN        A    B     RHODE IS    A    B      
PENN        A    N     NEW JERSEY  A    B     W VIRGINIA  A    N      
MARYLAND    A    B     DELAWARE    A    B     VIRGINIA    A    N      
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N      
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  A    A      
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  A    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. 
 
$$