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 EST Tue February 25 2020 
 
6-10 DAY OUTLOOK FOR MAR 02 - 06 2020 
 
Model solutions predict an amplified ridge over the North Pacific with positive  
500-hPa height anomalies extending eastward to the Pacific coast of the CONUS.  
Negative 500-hPa height anomalies centered over the Arctic Ocean extend  
southward into mainland Alaska and the Alaska Panhandle in all model solutions.  
Model forecasts from the ECMWF, GEFS and Canadian ensembles are in agreement on  
a transient pattern over the CONUS during the 6-10 day period, indicating  
trough development downstream of the predicted ridge over the western central  
CONUS or the eastern North Pacific in some ensemble members. The manual blend  
of recent ECMWF, GEFS and Canadian ensemble means indicates below normal  
500-hPa heights over the western CONUS, excluding coastal areas of Oregon and  
California, and above normal 500-hPa heights approximately from the Mississippi  
Valley to the Atlantic Coast.  
 
Predicted troughing and generally below normal 500-hPa heights over Alaska lead  
to probable below normal temperatures in the 6-10 day period for most of the  
state, with the exception of the western Aleutians. Under predicted northerly  
flow and a trough, near to below normal temperatures are likely for much of the  
western CONUS. Above normal temperatures are likely during the 6-10 day period  
for the Intermountain West and Great Plains, under anomalous southerly flow.  
Above normal temperatures are also likely from the Mississippi Valley to the  
Atlantic Coast under predicted positive 500-hPa height anomalies.  
 
A strong upper-level jet and potential storm track leads to likely above normal  
precipitation for much of Alaska and parts of the Pacific Northwest. The  
predicted trough over the western central CONUS during the 6-10 day period  
leads to likely above normal precipitation for much of the CONUS from the Rocky  
Mountains eastward. Higher probabilities for above normal precipitation extend  
from the Southwest, across the Central Plains, into the central Mississippi  
Valley and Great Lakes region. Near to below normal precipitation is more  
likely for much of California and Nevada, as the predicted ridge over the North  
Pacific may push eastward into the coast. Below normal precipitation is also  
more likely for parts of southern Texas and the Florida Peninsula, in areas  
that are predicted to be south of potential storm tracks.  
 
The official 6-10 day 500-hPa height blend consists of 25% of Today's 6z GFS  
Ensemble Mean centered on Day 8, 50% of Today's 0z European Ensemble Mean  
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: About average, 3 out of 5, due to  
good agreement among model ensemble mean forecasts, offset by a predicted  
transient pattern and differences in temperature tools over the western CONUS.  
 
8-14 DAY OUTLOOK FOR MAR 04 - 10 2020  
 
The predicted circulation pattern during the 8-14 day period is similar to the  
forecast for the 6-10 day period, however there is much greater ensemble spread  
and uncertainty around the amplitude and location of a trough over the eastern  
North Pacific or the western CONUS and downstream ridging. While all models  
indicate an amplification of the predicted ridge over the western North  
Pacific, a significant de-amplification of downstream anomalies is indicated by  
model ensemble means. The ECMWF ensemble mean in particular shows no  
significant height anomalies over the western CONUS. The manual blend of  
500-hPa heights indicates weak negative 500-hPa height anomalies over the  
northwestern CONUS and positive 500-hPa height anomalies over the eastern  
CONUS, centered over the Southeast. A strong jet persists into the 8-14 day  
period across southern Alaska in model forecasts, with positive 500-hPa  
anomalies over southwestern Alaska, and negative 500-hPa anomalies over  
mainland Alaska and the Alaska Panhandle.  
 
The temperature pattern forecast for the 8-14 day period is generally similar  
to the pattern forecast for the 6-10 day period, with an expansion of the areas  
of potentially near normal temperatures over the western CONUS, and a general  
decrease in the probabilities of below and above normal temperatures over the  
CONUS, with a large increase in ensemble spread and uncertainty. Below normal  
temperatures continue to be likely for Alaska, except for the western  
Aleutians, under relative troughing and below normal 500-hPa heights over much  
of the state.  
 
The precipitation pattern forecast for the 8-14 day period is similar to the  
pattern forecast for the 6-10 day period, with above normal precipitation  
likely for much of Alaska, along the predicted storm track, as well as for much  
of the CONUS, ahead of a developing trough over the west, while the area of  
potential near normal precipitation has increased across the western CONUS and  
probabilities of above normal precipitation have decreased in magnitude, due to  
increasing uncertainty in the circulation pattern.  
 
The official 8-14 day 500-hPa height blend consists of: 25% of Today's 6z GFS  
Ensemble Mean centered on Day 11, 50% of Today's 0z European Ensemble Mean  
centered on Day 11, and 25% 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 predicted transient circulation pattern during the forecast period, a large  
increase in ensemble spread, and differences in temperature tools over the  
western CONUS.  
 
FORECASTER: D Collins 
 
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  
March 19. 
 
 
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:  
20040308 - 19880307 - 20020212 - 19590227 - 19530223 
 
 
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:  
20040308 - 19590302 - 20020221 - 19940309 - 20080214 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Mar 02 - 06 2020 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    A     OREGON      B    N     NRN CALIF   N    B      
SRN CALIF   N    B     IDAHO       N    A     NEVADA      N    N      
W MONTANA   N    A     E MONTANA   A    A     WYOMING     B    A      
UTAH        N    A     ARIZONA     B    A     COLORADO    N    A      
NEW MEXICO  N    A     N DAKOTA    A    A     S DAKOTA    A    A      
NEBRASKA    A    A     KANSAS      A    A     OKLAHOMA    A    A      
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A      
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A      
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   A    A      
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A      
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A      
TENNESSEE   A    A     ALABAMA     A    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    B     AK N SLOPE  B    A      
AK ALEUTIAN B    A     AK WESTERN  B    A     AK INT BSN  B    A      
AK S INT    B    A     AK SO COAST B    A     AK PNHDL    B    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Mar 04 - 10 2020 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    N     OREGON      N    N     NRN CALIF   N    N      
SRN CALIF   N    A     IDAHO       N    N     NEVADA      N    N      
W MONTANA   N    A     E MONTANA   N    A     WYOMING     N    A      
UTAH        N    A     ARIZONA     B    A     COLORADO    N    A      
NEW MEXICO  N    A     N DAKOTA    A    A     S DAKOTA    A    A      
NEBRASKA    A    A     KANSAS      A    A     OKLAHOMA    A    N      
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    N      
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A      
ARKANSAS    A    A     LOUISIANA   A    N     WISCONSIN   A    A      
ILLINOIS    A    A     MISSISSIPPI A    A     MICHIGAN    A    A      
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A      
TENNESSEE   A    A     ALABAMA     A    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    N     FL PENIN    A    N     AK N SLOPE  B    A      
AK ALEUTIAN N    N     AK WESTERN  B    A     AK INT BSN  B    A      
AK S INT    B    A     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. 
 
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