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 Fri June 28 2024 
 
6-10 DAY OUTLOOK FOR JUL 04 - 08 2024 
 
Today’s model solutions are consistent with yesterday’s, with the GEFS, ECMWF  
(ECENS), and Canadian (ECCC) ensemble means all depicting a similar synoptic  
picture over the forecast domain during the 6-10 day forecast period. Weakly  
positive 500-hPa height anomalies are favored over much of the Contiguous U.S.  
(CONUS) with a weak jet stream stretching across Canada. A broad, low-amplitude  
trough is depicted over Hudson Bay and the Great Lakes region. Models indicate  
an amplified pattern over Alaska with a strong ridge over the Bering Sea and a  
shortwave trough immediately downstream over the Gulf of Alaska. 
 
Expansive positive 500-hPa height anomalies over the CONUS favor above-normal  
temperatures for most of the Lower 48. Models depict the largest height  
departures over the West Coast and the Southeast U.S., and accordingly the  
consensus among forecast tools place the highest odds for above-normal  
temperatures in the same regions, exceeding 70% probability for portions of  
California and much of the southeastern CONUS. Under the influence of the weak  
troughing over Hudson Bay, portions of the Northern Plains tilt slightly  
towards below-normal temperatures. Near-normal temperatures are favored for  
western Washington with enhanced onshore flow under the influence of strong  
surface high pressure over the North Pacific. Enhanced onshore flow off the  
Bering Sea favors below-normal temperatures for western Alaska and extending  
into the Alaskan Interior, while near-normal temperatures are likely for the  
rest of the state. Most of Hawaii is also favored for near-normal temperatures,  
while Oahu and Kawai tilt towards below-normal temperatures, consistent with  
the Hawaii CON. 
 
Model ensembles depict an active North American Monsoon (NAM) during the  
forecast period, resulting in a tilt towards above-normal precipitation for  
portions of the Desert Southwest and extending into the Central Plains, while  
troughing over eastern Canada extends the area favored to receive  above-normal  
precipitation into the Ohio Valley, Great Lakes and Northeast U.S. With a  
northward-shifted jet stream most forecast tools favor below-normal  
precipitation for much of the northwestern CONUS. Signals regarding  
precipitation from the forecast tools are weak over the southeastern CONUS,  
therefore near-normal precipitation is favored for much of the Gulf Coast and  
Southeast U.S. Cool onshore flow tilts much of Alaska toward above-normal  
precipitation with the exception of the Alaskan Peninsula and the Panhandle,  
where near-normal precipitation is favored. Above-normal precipitation is also  
favored for Hawaii, consistent with today’s autoblend. 
 
The official 6-10 day 500-hPa height blend consists of 34% of Today's 0z GFS  
Ensemble Mean centered on Day 8, 33% of Today's 0z European Ensemble Mean  
centered on Day 8, and 33% 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, with  
good run-to-run continuity among forecast models, offset by differences between  
models regarding strength and position of various synoptic features. 
 
8-14 DAY OUTLOOK FOR JUL 06 - 12 2024  
 
Model ensembles depict a general persistence of the synoptic pattern from the  
6-10 day period. The most notable difference is a weakening of the trough over  
eastern Canada, and model solutions also favor a de-amplification of the  
ridge/trough pattern over the Alaska region. Over the CONUS widespread positive  
height anomalies remain and shift slightly northward. 
 
Above-normal temperatures continue to be favored for most of the CONUS,  
expanding to include the Northern Plains as weak troughing retreats into  
Canada. Chances for above-normal temperatures remain highest (>50%) over  
portions of California and for much of the southeastern CONUS. Near-normal  
temperatures continue to be favored for western Washington with the synoptic  
pattern likely to enhance onshore flow. Ongoing onshore flow off the  
anomalously cool waters of the Bering Sea results in an expansion of  
probabilities for below-normal temperatures, now covering the entire state with  
highest probabilities (>50%) along the western coast. 
 
Models maintain an active NAM during week-2, enhancing chances for above-normal  
precipitation for portions of the Desert Southwest. Increasing activity is  
favored by model solutions in the tropics, resulting in a tilt towards  
above-normal precipitation for the Gulf Coast and up along the Eastern  
Seaboard, while northward-shifting positive height anomalies over the CONUS  
bring a slight tilt towards below-normal precipitation for portions of the  
Middle Mississippi Valley. Below-normal precipitation continues to be favored  
for much of the northwestern CONUS with models generally keeping precipitation  
along the West Coast north of the Canadian border. Above-normal precipitation  
is favored to continue over Alaska due to enhanced onshore flow off the Bering  
Sea. Above-normal precipitation also remains slightly favored for Hawaii,  
consistent with the Hawaii CON. 
 
The official 8-14 day 500-hPa height blend consists of: 34% of Today's 0z GFS  
Ensemble Mean centered on Day 11, 33% of Today's 0z European Ensemble Mean  
centered on Day 11, and 33% 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, with  
good run-to-run continuity among forecast models, offset by differences between  
models regarding strength and position of various synoptic features. 
 
FORECASTER: Daniel Barandiaran 
 
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 1991-2020 base period means as reference in  
the climate outlooks. 
 
The next set of long-lead monthly and seasonal outlooks will be released on  
July 18. 
 
 
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:  
19510608 - 19520608 - 19530608 - 19540608 - 19550608 
 
 
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:  
19510607 - 19520607 - 19530607 - 19540607 - 19550607 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Jul 04 - 08 2024 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    B     IDAHO       A    B     NEVADA      A    B      
W MONTANA   N    B     E MONTANA   B    N     WYOMING     N    N      
UTAH        A    B     ARIZONA     A    A     COLORADO    A    N      
NEW MEXICO  A    A     N DAKOTA    B    A     S DAKOTA    B    A      
NEBRASKA    N    N     KANSAS      A    A     OKLAHOMA    A    A      
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    A      
MINNESOTA   N    A     IOWA        A    A     MISSOURI    A    A      
ARKANSAS    A    A     LOUISIANA   A    N     WISCONSIN   A    A      
ILLINOIS    A    A     MISSISSIPPI A    N     MICHIGAN    A    A      
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A      
TENNESSEE   A    N     ALABAMA     A    N     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    N     S CAROLINA  A    N     GEORGIA     A    N      
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  N    A      
AK ALEUTIAN N    N     AK WESTERN  B    A     AK INT BSN  B    A      
AK S INT    N    A     AK SO COAST N    N     AK PNHDL    N    N      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Jul 06 - 12 2024 
 
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    B     E MONTANA   A    N     WYOMING     A    N      
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A      
NEW MEXICO  A    A     N DAKOTA    A    N     S DAKOTA    A    N      
NEBRASKA    A    N     KANSAS      A    N     OKLAHOMA    A    N      
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A      
MINNESOTA   A    N     IOWA        A    N     MISSOURI    A    B      
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   A    N      
ILLINOIS    A    B     MISSISSIPPI A    N     MICHIGAN    A    N      
INDIANA     A    N     OHIO        A    N     KENTUCKY    A    N      
TENNESSEE   A    N     ALABAMA     A    N     NEW YORK    A    N      
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    A      
MASS        A    A     CONN        A    N     RHODE IS    A    A      
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    N      
MARYLAND    A    N     DELAWARE    A    N     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  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    N      
  
                           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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