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 April 16 2025 
 
6-10 DAY OUTLOOK FOR APR 22 - 26 2025 
 
The extended range forecast continues to track as general agreement continues  
among today’s GEFS, ECMWF, and CMCE depictions of 500-hPa height anomalies  
during the forecast period. Differences remain with regard to the strength of  
various synoptic features, but regardless model solutions are generally  
trending in the same direction. 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 60%. With models favoring weakening negative height  
anomalies over the West and persistent broad southeasterly flow at the surface  
over the Great Plains, chances of above-normal temperatures have spread  
westward from yesterday’s outlook, with probabilities now exceeding 50% for  
much of the Great Basin and Central Rockies. Near-normal temperatures are  
indicated along the immediate West Coast and along the U.S.-Canada border,  
under weaknesses in the broad ridging over North America and the North Pacific.  
For Alaska, easterly flow along the Canada border tilts the odds towards  
below-normal temperatures for most of the state, while strong ridging over the  
North Pacific favors above-normal temperatures for the Alaskan Peninsula and  
the Aleutians. Above-normal temperatures are also favored for Hawaii,  
consistent with most forecast tools. 
 
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 northeastern Texas).  
Chances of above-normal precipitation fall away to the west and northeast, with  
near-normal precipitation favored over the Desert Southwest and portions of the  
Great Basin, as well as the eastern Great Lakes and New England. Forecast tools  
generally favor near- to below-normal precipitation for much of the West Coast  
and Great Basin 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. 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 24 - 30 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 heights 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, with  
enhanced above-normal probabilities spreading northward into the Northern  
Plains resulting from strong southeasterly surface flow. Above-normal  
temperatures are also indicated east of the Rockies and west into the Great  
Basin, with enhanced probabilities (>60% chance) from the Gulf Coast north into  
the Mississippi and Tennessee Valleys and the Central Plains. Near-normal  
temperatures are favored for much of California and Desert Southwest 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  
Alaskan Peninsula and 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 where near-normal precipitation is  
most likely. Chances of above-normal precipitation are enhanced over the Great  
Plains and Mississippi Valley, particularly for the Central Plains and Middle  
Mississippi Valley where chances top 50%. Near-normal precipitation is favored  
along the northern half of the West Coast, as well as for much of the Desert  
Southwest, consistent with most forecast tools. Persistent surface low pressure  
over the Bering Sea favors above-normal precipitation for most of Alaska, with  
near-normal precipitation indicated for portions of the Aleutian Islands.  
Hawaii continues to tilt towards above-normal precipitation, consistent with  
the Hawaii CON. 
 
The official 8-14 day 500-hPa height blend consists of: 33% of Today's 0z GFS  
Ensemble Mean centered on Day 11, 34% 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:  
20000329 - 19900403 - 19700327 - 19510411 - 20020328 
 
 
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:  
20000401 - 19700326 - 19990420 - 19730425 - 19860408 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Apr 22 - 26 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  N    N     OREGON      A    N     NRN CALIF   A    N      
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    N      
W MONTANA   N    N     E MONTANA   N    A     WYOMING     A    A      
UTAH        A    N     ARIZONA     A    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    N     OHIO        A    N     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    N     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    A     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 24 - 30 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   N    N      
SRN CALIF   N    A     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    A     E MONTANA   A    A     WYOMING     A    A      
UTAH        A    A     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    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 A    A     AK WESTERN  B    A     AK INT BSN  B    A      
AK S INT    N    A     AK SO COAST N    A     AK PNHDL    N    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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