Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EDT Fri May 23 2025 
 
6-10 DAY OUTLOOK FOR MAY 29 - JUN 02, 2025 
 
Today's ensemble mean solutions are in good agreement in depicting a high  
amplitude 500-hPa height pattern across much of North America. The period  
begins with a powerful trough over the Gulf of Alaska with a second trough to  
its north near northwestern Mainland Alaska. An anomalous ridge is forecast  
downstream stretching from central Canada to the western Contiguous United  
States (CONUS). Anomalous troughing is forecast across much of the eastern  
CONUS centered near the Great Lakes and Ohio Valley. Generally near normal  
heights are forecast for Hawaii. As time progresses, the trough over the Gulf  
of Alaska is expected to weaken as the flow pattern becomes more zonal.  
However, the second trough near the northwestern Mainland is forecast to  
persist and retrograde slightly to the Bering Sea. The ridging across the West  
is forecast to persist throughout most of the period with above normal heights  
prevailing across the region. However, the flow becomes more zonal by day 10.  
The trough over the eastern CONUS is expected to progress toward the coast and  
temporarily strengthen around day 8 before weakening at the end of the period.  
Near normal heights are generally forecast to persist for Hawaii with troughing  
indicated northwest of the state and ridging forecast southeast of the state.  
 
With multiple troughs expected in the vicinity of Alaska, below normal  
temperatures are favored for most of the state. Above normal temperatures are  
likely downstream across most of the western CONUS and northern Plains.  
Probabilities of above normal temperatures exceed 80 percent for parts of  
northeastern California and the western Great Basin as anomalous ridging is  
forecast to build across the region during the middle of the period. Below  
normal temperatures are likely for much of the south-central and southeastern  
CONUS northward to the Middle Mississippi Valley, eastern Great Lakes, and  
Mid-Atlantic states. The area most likely to experience below normal  
temperatures is centered over the Tennessee Valley. A slight tilt toward above  
normal temperatures are indicated for parts of Northern New England ahead of  
the predicted mean trough axis. Above normal temperatures are favored for much  
of the Florida Peninsula to the south of the predicted mean frontal boundary.  
Above normal temperatures are favored for Hawaii, due in large part to above  
normal sea surface temperatures (SSTs) in adjacent waters.  
 
An active period is anticipated across Alaska with multiple troughs affecting  
the state. Above normal precipitation is favored for most of the state. The  
highest likelihood of above normal precipitation is forecast for Southeast  
Alaska early in the period, due to anticipated anomalous onshore flow ahead of  
the strong trough forecast over the Gulf of Alaska. Thereafter, the most likely  
area of above normal precipitation shifts to the west along the South Coast, as  
a surface low develops near the Aleutians. Ridging is forecast to strengthen  
across the West by the middle of the period, leading to increased chances of  
drier than normal weather across much of Northern California, the Pacific  
Northwest, the Columbia River Valley, and parts of the Northern Rockies.  
Surface high pressure is forecast across much of the north-central CONUS. As  
such, below normal precipitation is most likely for the western and central  
Great Lakes, the Upper Mississippi Valley, and parts of the Northern Plains.  
This surface high is expected to push a frontal boundary farther to the south  
than typical this time of year, leading to increased precipitation chances  
across much of the Southern CONUS. The tail end of this frontal boundary will  
likely be a focal point for increased precipitation chances for the Southern  
Plains into the Southern and Central Rockies. Potential moisture advection from  
both the Gulf and from potential tropical activity in the Pacific may also  
contribute to increased totals across this region. Above normal precipitation  
is also favored along the Eastern Seaboard ahead of the predicted mean trough  
axis over the eastern CONUS and due to potential surface low development over  
eastern Canada. A slight tilt toward above normal precipitation is indicated  
for Hawaii, consistent with calibrated precipitation amounts from the ECMWF and  
GEFS ensembles. 
 
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, and 30% 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, due to  
good agreement among today’s ensemble means. 
 
8-14 DAY OUTLOOK FOR MAY 31 - JUN 06, 2025  
 
The week-2 period begins with a highly amplified pattern featuring anomalous  
ridging across much of the West and Northern Plains. Troughs are predicted over  
Alaska and the Eastern Seaboard. As time progresses the pattern becomes  
significantly more zonal as the trough over the Gulf of Alaska weakens and the  
resultant downstream flow flattens. By the middle of week-2, most model  
solutions predict near to above normal heights overspreading most of the CONUS  
in this lower amplitude pattern. An exception is for western parts of Mainland  
Alaska where residual troughing is forecast to persist but with diminished  
amplitude. Persistent troughing or a weakness in subtropical ridging is  
forecast across the eastern Gulf Coast region for the duration of the period.  
Generally near normal heights are expected for Hawaii throughout the period.  
 
Below normal temperatures remain likely across Alaska due to predicted  
troughing, especially early in the period. Ridging and above normal heights are  
forecast to persist across most of the West, leading to increased probabilities  
of above normal temperatures across this region. A slight tilt toward above  
normal temperatures is also indicated for parts of the Northern Plains due to  
predicted ridging early in the period. Below normal temperatures are favored  
for much of the southeastern and south-central CONUS, due to mean troughing  
predicted from the Eastern Seaboard to the Gulf Coast region. Above normal  
temperatures are favored across parts of the Northeast ahead of the predicted  
mean trough axis. Above normal temperatures are favored for the southern half  
of the Florida Peninsula and southern Texas to the south of a mean frontal  
boundary. A tilt toward above normal temperatures is also forecast for Hawaii  
due to above normal SSTs. 
 
An active pattern is anticipated to continue into week-2 for much of the  
southern tier of the CONUS. A predicted frontal boundary early in the period  
leads to increased chances of above normal precipitation from the southern and  
central High Plains and Southern and Central Rockies eastward across the Gulf  
Coast region. The tropics may also be a player in increasing precipitation  
chances in the southern CONUS. The potential development of a tropical system  
in the eastern Pacific may lead to increased mid-level moisture advection to  
portions of the southern High Plains. Additionally, daily model output is  
indicating the potential for increased tropical moisture flow into the eastern  
Gulf Coast region during the second half of week-2. A slight tilt toward above  
normal precipitation is also indicated for the East Coast, near and ahead of a  
predicted mean trough axis centered over the Appalachians. Conversely,  
predicted expansive surface high pressure favors a drier than normal pattern  
across most of the northern CONUS from the western Great Lakes to the Northern  
Plains. Below normal precipitation is likely for the northwestern CONUS due to  
predicted mid-level ridging. An active pattern remains favored for most of  
Alaska, due to predicted mean cyclonic mid-level flow. The greatest chances of  
above normal precipitation is indicated for southwestern Mainland Alaska and  
the Alaska Peninsula, associated with predicted surface low development near  
the eastern Aleutians. A slight tilt toward above normal precipitation is  
indicated for Hawaii, consistent with calibrated precipitation amounts from the  
ECMWF and GEFS ensembles. 
 
The official 8-14 day 500-hPa height blend consists of: 20% of Today's 6z GFS  
Ensemble Mean centered on Day 11, 50% of Today's 0z European Ensemble Mean  
centered on Day 11, and 30% of Today's 0z Canadian Ensemble Mean centered on  
Day 11  
 
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to good  
model agreement on an amplified pattern early in the period offset by increased  
uncertainty associated with a potential change to a more zonal pattern later in  
the period.  
 
FORECASTER: Scott H 
 
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  
June 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:  
20040530 - 20010603 - 20060511 - 19610521 - 20030515 
 
 
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:  
20010602 - 20040602 - 20060511 - 20030514 - 19660515 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for May 29 - Jun 02, 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    N      
UTAH        A    N     ARIZONA     A    A     COLORADO    A    A      
NEW MEXICO  B    A     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    N    N     KANSAS      B    N     OKLAHOMA    B    A      
N TEXAS     B    A     S TEXAS     N    A     W TEXAS     B    A      
MINNESOTA   A    B     IOWA        N    B     MISSOURI    B    N      
ARKANSAS    B    A     LOUISIANA   N    A     WISCONSIN   N    B      
ILLINOIS    B    B     MISSISSIPPI B    A     MICHIGAN    N    B      
INDIANA     B    N     OHIO        B    N     KENTUCKY    B    N      
TENNESSEE   B    A     ALABAMA     B    A     NEW YORK    N    N      
VERMONT     N    A     NEW HAMP    N    A     MAINE       A    A      
MASS        N    A     CONN        N    A     RHODE IS    N    A      
PENN        B    N     NEW JERSEY  B    A     W VIRGINIA  B    N      
MARYLAND    B    A     DELAWARE    B    A     VIRGINIA    B    A      
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A      
FL PNHDL    N    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    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for May 31 - Jun 06, 2025 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B      
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N      
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    A      
UTAH        A    A     ARIZONA     A    A     COLORADO    N    A      
NEW MEXICO  N    A     N DAKOTA    A    B     S DAKOTA    N    B      
NEBRASKA    N    N     KANSAS      B    A     OKLAHOMA    B    A      
N TEXAS     B    A     S TEXAS     N    A     W TEXAS     B    A      
MINNESOTA   A    B     IOWA        N    B     MISSOURI    B    A      
ARKANSAS    B    A     LOUISIANA   B    A     WISCONSIN   N    B      
ILLINOIS    B    B     MISSISSIPPI B    A     MICHIGAN    N    B      
INDIANA     N    B     OHIO        N    N     KENTUCKY    B    N      
TENNESSEE   B    A     ALABAMA     B    A     NEW YORK    N    N      
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A      
MASS        A    A     CONN        N    A     RHODE IS    A    A      
PENN        N    N     NEW JERSEY  N    A     W VIRGINIA  N    N      
MARYLAND    N    A     DELAWARE    N    A     VIRGINIA    N    A      
N CAROLINA  N    A     S CAROLINA  N    A     GEORGIA     B    A      
FL PNHDL    N    A     FL PENIN    A    A     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 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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