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 Tue April 15 2025 
 
6-10 DAY OUTLOOK FOR APR 21 - 25 2025 
 
There is reasonable agreement among today’s GEFS, ECMWF, and CMCE depictions of  
500-hPa height anomalies during the extended range forecast period and the  
Canadian has come into better agreement with the GEFS and ECMWF, but these two  
models are not as well-aligned as yesterday. Regardless, the 500-hPa manual  
blend continues to depict amplified ridges over the North Pacific and eastern  
Contiguous U.S. (CONUS) and a weak trough over the West.  
  
Amplified ridging over the East favors above-normal temperatures for most of  
the CONUS east of the Rockies, particularly over the Southeast U.S. where  
probabilities exceed 70%. With models favoring a weaker trough over the West a  
slight tilt towards above-normal temperatures is introduced to much of the  
Great Basin in today’s 6-10 day outlook. Northerly surface flow over the  
Pacific Northwest results in a tilt towards below-normal temperatures from  
Washington and Oregon east into the Northern Rockies. Near-normal temperatures  
are favored for the Northern Plains and Upper Midwest, consistent with most  
forecast tools. For Alaska, easterly flow along the Canada border tilts the  
odds towards below-normal temperatures for the eastern half of the state, while  
strong ridging over the North Pacific favors above-normal temperatures for  
southwestern Alaska and the Aleutians. Above-normal temperatures are also  
favored for Hawaii, with probabilities increasing from southeast to northwest. 
 
The trough/ridge pattern over North America leads to a fairly wet pattern east  
of the Rockies. Multiple models indicate periods of enhanced precipitation over  
the Mississippi Valley throughout the forecast period, where above-normal  
precipitation is most strongly favored (>50% centered over Oklahoma). Chances  
of above-normal precipitation fall away to the east and west, with near-normal  
precipitation favored over the Desert Southwest and portions of the Great  
Basin, as well as along portions of the Eastern Seaboard. Forecast tools  
generally favor below-normal precipitation for much of the West Coast with  
amplified ridging upstream. Weak but persistent surface low pressure over the  
Bering Sea brings southerly flow into the southern Alaskan coast, tilting the  
odds towards above-normal precipitation for much of the state, especially the  
southern half of the state where probabilities exceed 50%.. Forecast tools also  
indicate above-normal precipitation for Hawaii, consistent with the Hawaii CON  
and 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: About average, 3 out of 5, due to  
good agreement among the forecast tools with regard to temperature and  
precipitation, offset by diverging model solutions as the period progresses. 
 
8-14 DAY OUTLOOK FOR APR 23 - 29 2025  
 
Similar to the 6-10 day period there is good agreement on the overall synoptic  
pattern and evolution. The ECMWF, GEFS, and CMCE all depict a transition to  
more zonal flow over the CONUS and positive height anomalies across most of  
North America, but the Canadian deviates from the GEFS and ECMWF, eroding the  
weak trough over the Intermountain West more quickly than the other models. The  
500-hPa manual height blend features weak positive height across most of the  
CONUS, while weak negative heights nose into California from the west and into  
Mainland Alaska from the east.    
  
The week-2 temperature outlook is very similar to the 6-10 day period, although  
probabilities are generally lower, likely to increased zonal flow..  
Above-normal temperatures are indicated east of the Rockies and west into the  
Great Basin, with enhanced probabilities (>50% chance) from the Gulf Coast  
north into the Mississippi and Ohio Valleys and the Mid-Atlantic. Near-normal  
temperatures are favored along the U.S.-Canada border and down the West Coast,  
while southern California and Arizona tilt weakly towards below-normal  
temperatures under weak negative 500-hPa heights. Easterly flow persists over  
Mainland Alaska, resulting in near- to below-normal temperatures being favored  
for most of the state, while a slight tilt towards above-normal temperatures  
remains over the Aleutian Islands. 
  
Likewise, the week-2 precipitation outlook is very similar to the 6-10 day  
period. Above-normal precipitation is generally favored from the Rockies  
eastward, with the exception of New England and southern Florida where  
near-normal precipitation is most likely. Chances of above-normal precipitation  
are enhanced over the Great Plains and Mississippi Valley, particularly for the  
Arklatex region where chances top 50%. Below-normal precipitation continues to  
be favored along the northern half of the West Coast, and near-normal  
precipitation is most likely for much of the Desert Southwest and the Great  
Basin. Persistent surface low pressure over the Bering Sea favors above-normal  
precipitation for most of the state, with near-normal precipitation indicated  
for portions of the Aleutian Islands. Hawaii continues to tilt towards  
above-normal precipitation, consistent with most forecast tools. 
 
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: About average, 3 out of 5, due to  
good agreement among the forecast tools with regard to temperature and  
precipitation, offset by diverging model solutions and weak forecast anomalies. 
 
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  
April 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:  
19860407 - 20060423 - 20000326 - 19880408 - 20040328 
 
 
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:  
20000325 - 20060423 - 19880410 - 20090327 - 19860407 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Apr 21 - 25 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  B    B     OREGON      N    B     NRN CALIF   N    B      
SRN CALIF   N    N     IDAHO       N    N     NEVADA      A    N      
W MONTANA   B    A     E MONTANA   B    A     WYOMING     N    A      
UTAH        A    A     ARIZONA     N    N     COLORADO    A    A      
NEW MEXICO  A    A     N DAKOTA    N    A     S DAKOTA    N    A      
NEBRASKA    A    A     KANSAS      A    A     OKLAHOMA    A    A      
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A      
MINNESOTA   N    A     IOWA        A    A     MISSOURI    A    A      
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   N    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    N     NEW HAMP    A    N     MAINE       A    N      
MASS        A    N     CONN        A    N     RHODE IS    A    N      
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    N     AK N SLOPE  B    N      
AK ALEUTIAN A    A     AK WESTERN  N    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 Apr 23 - 29 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    N     OREGON      N    N     NRN CALIF   N    N      
SRN CALIF   B    N     IDAHO       A    N     NEVADA      A    N      
W MONTANA   N    A     E MONTANA   N    A     WYOMING     A    A      
UTAH        A    N     ARIZONA     N    N     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     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    N      
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N      
MASS        A    N     CONN        A    N     RHODE IS    A    N      
PENN        A    A     NEW JERSEY  A    N     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    N     AK N SLOPE  B    A      
AK ALEUTIAN N    A     AK WESTERN  B    A     AK INT BSN  B    A      
AK S INT    B    A     AK SO COAST N    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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