NWS Climate Prediction Center



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Latest 6 to 10 Day Temperature Outlook

Prognostic Discussions


Valid: Oct 08 - 12, 2023 (6-10 Day Outlook)
Valid: Oct 10 - 16, 2023 (8-14 Day Outlook)
Issued: Oct 02, 2023


Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks 
NWS Climate Prediction Center College Park, MD 
300 PM EDT Mon October 02 2023 
 
6-10 DAY OUTLOOK FOR OCT 08 - 12 2023 
 
There is considerably less uncertainty than at the end of last week regarding  
the mid-level height pattern during the extended range period. Models are in  
general agreement showing the 6-10 day period starting out fairly amplified,  
with mid-level troughs over the eastern North Pacific and the eastern CONUS  
while a strong anomalous ridge is centered south of Greenland. The GEFS is a  
bit stronger and farther southeast with the North Pacific trough than the other  
ensemble means. Meanwhile, a mid-level ridge is expected to be centered near  
the Canadian Prairies with an axis extending southward just west of the Front  
Range of the Rockies. Guidance is less consistent with this feature than with  
others; the European ensemble mean is stronger than the GEFS and the Canadian  
ensemble mean with this feature. There is also some discrepancy near Hudson  
Bay, as the GEFS and European ensemble mean keep 500-hPa heights somewhat  
higher than the Canadian ensemble mean, but none of the inconsistencies has  
much of an effect on sensible weather across the CONUS.  
 
This is likely a transient pattern, with some progression and de-amplification  
taking place as the 6-10 period progresses. Teleconnections indicate that the  
well above-normal 500-hPa heights south of Greenland are not consistent with a  
strong mid-level trough over the north-central or northeastern North Pacific.  
This is borne out in all the ensemble means, though there are some  
discrepancies regarding the placement and strength of specific features,  
especially at the end of the period. By day 9, most guidance shows a weaker  
mid-level trough farther east in the North Pacific and a weakening trough that  
has moved from the eastern CONUS into or near the western North Atlantic Ocean,  
a positive 500-hPa height anomaly center near Hudson Bay, and a trough in the  
northeastern North Pacific, with subnormal 500-hPa heights extending near or  
into the Pacific Northwest. The Canadian ensemble means show lower heights near  
Hudson Bay and a larger positive 500-hPa anomaly across part of the western  
CONUS compared to the GEFS and European ensemble means. The preponderance of  
the guidance favors the higher 500-hPa heights near Hudson Bay and mid-level  
heights closer to normal in the western CONUS, so this is the favored solution  
at this time. 
 
By day 10 or shortly thereafter, another change in the mid-level pattern is  
getting underway, showing some retrogression and re-amplification of features  
across Canada, the northwestern CONUS, and the North Pacific, which will be  
most notable during week-2. The European ensemble mean is slower to start this  
retrogression than the other ensemble means, but all show it well underway by  
the middle of week-2. 
 
The favored 6-10 day pattern would lead to below-normal temperatures from the  
eastern to the south-central CONUS near and behind the strong mid-level trough.  
Cold weather may impact vulnerable crops during the last half of the period in  
the middle Ohio Valley, central Appalachians, and adjacent areas. Meanwhile,  
the Canadian ridge favors above-normal temperatures farther west from the upper  
Mississippi Valley and Great Plains to the West Coast, with the best odds for  
warmth in the northern halves of the High Plains and eastern Rockies, closest  
to the mid-level ridge centered near the Canadian Prairies. Farther east,  
downstream from the ridge and upstream from the trough, below-normal  
precipitation is most likely, except for some potential moisture intrusion  
along the Gulf Coast, and some storminess in part of New England just  
downstream from the eastern CONUS trough. 
 
The mid-level trough southeast of Alaska is expected to bring heavy  
precipitation into the Pacific Northwest, with odds for above-normal  
precipitation exceeding 60 percent from the Cascades westward. In addition,  
this feature favors wet weather in eastern and particularly southeastern Alaska  
near and east of the trough axis. The low 500-hPa heights also somewhat enhance  
chances for below-normal temperatures over most of Mainland Alaska. 
 
The official 6-10 day 500-hPa height blend consists of 15% of Today's 6z GFS  
Ensemble Mean centered on Day 8, 35% of Today's GFS Superensemble Mean centered  
on Day 8, 15% of Today's operational 6z GFS centered on Day 8, 10% of Today's  
0z European Ensemble Mean centered on Day 8, 15% of Today's operational 0z  
ECMWF centered on Day 8, and 10% 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  
general agreement among the tools on the broadscale pattern, with the noted  
discrepancies not having a dramatic impact on sensible weather in the CONUS and  
Alaska. 
 
8-14 DAY OUTLOOK FOR OCT 10 - 16 2023  
 
During week-2, retrogression of the de-amplified pattern is expected, along  
with some re-amplification of certain features. By the end of the period, a  
positive 500-hPa anomaly center is forecast west of Hudson Bay and north of the  
Canadian Prairies while the strong mid-level trough near the western CONUS is  
re-positioned westward and broadened, with the axis extending southward into  
the North Pacific well west of the Pacific Northwest. There is a bit more  
uncertainty in the East, but 500-hPa heights should generally be near to  
slightly below normal, with a weak trough axis from near the New England coast  
southeastward into the North Atlantic. 
 
The re-building heights in Canada and the weakening of the mid-level trough in  
the East should displace the cold air that settled into the eastern CONUS  
during the 6-10 day period, with temperatures climbing above normal there by  
the end of week-2. The speed of this transition is uncertain, as are the  
temperature anomalies early in the period - good radiational cooling underneath  
surface high pressure could allow nighttime temperatures to drop lower than  
indicated by guidance during days 8 and 9. This uncertainty led to a forecast  
favoring neither colder than normal nor warmer than normal temperatures in much  
of the East. But odds favor above-normal temperatures over the rest of the  
CONUS, with the most enhanced chances in the northern Plains closest to the  
mid-level high pressure centered north of the Canadian Prairies. The  
precipitation forecast pattern is similar to the 6-10 day period, with dry  
weather slightly favored over much of the interior CONUS and parts of the East  
Coast and wetter than normal weather in the Northwest and near the Gulf Coast.  
With the mid-level ridge center established well north in Canada, some return  
flow of Gulf moisture is possible late week-2, reducing the odds for subnormal  
precipitation during week-2 as a whole across the interior CONUS. 
 
The trough south of Alaska will continue to favor wetter-than-normal weather in  
the eastern Mainland and southeastern Alaska and drier conditions farther west.  
In addition, the below-normal 500-hPa heights slightly increase the odds for  
below-normal temperatures over most of the Mainland and the Aleutians. 
 
The official 8-14 day 500-hPa height blend consists of: 45% of Today's 6z GFS  
Ensemble Mean centered on Day 11, 15% of Today's GFS Superensemble Mean  
centered on Day 11, 30% of Today's 0z European Ensemble Mean centered on Day  
11, and 10% of Today's 0z Canadian Ensemble Mean centered on Day 11  
 
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Near normal, 3 out of 5, for  
general agreement in the evolution of the mid-level height pattern, tempered by  
differences in the timing and magnitude of evolving features. 
 
FORECASTER: Rich Tinker 
 
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  
October 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:  
19941015 - 19830930 - 20081011 - 19981015 - 19841013 
 
 
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:  
19941015 - 19830929 - 20081010 - 19520911 - 19841013 
 
 
6-10 DAY OUTLOOK TABLE 
Outlook for Oct 08 - 12 2023 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A      
SRN CALIF   A    N     IDAHO       A    A     NEVADA      A    A      
W MONTANA   A    N     E MONTANA   A    B     WYOMING     A    B      
UTAH        A    N     ARIZONA     A    N     COLORADO    A    B      
NEW MEXICO  A    B     N DAKOTA    A    B     S DAKOTA    A    B      
NEBRASKA    A    B     KANSAS      A    B     OKLAHOMA    N    B      
N TEXAS     B    B     S TEXAS     B    N     W TEXAS     A    N      
MINNESOTA   A    B     IOWA        A    B     MISSOURI    N    B      
ARKANSAS    B    B     LOUISIANA   B    N     WISCONSIN   A    B      
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    B    B      
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    B      
TENNESSEE   B    B     ALABAMA     B    B     NEW YORK    B    N      
VERMONT     B    N     NEW HAMP    B    N     MAINE       N    N      
MASS        B    N     CONN        B    N     RHODE IS    B    N      
PENN        B    B     NEW JERSEY  B    B     W VIRGINIA  B    B      
MARYLAND    B    B     DELAWARE    B    B     VIRGINIA    B    B      
N CAROLINA  B    B     S CAROLINA  B    B     GEORGIA     B    B      
FL PNHDL    B    N     FL PENIN    B    N     AK N SLOPE  B    N      
AK ALEUTIAN B    B     AK WESTERN  B    B     AK INT BSN  B    A      
AK S INT    B    N     AK SO COAST B    B     AK PNHDL    N    A      
  
                            
 
8-14 DAY OUTLOOK TABLE 
Outlook for Oct 10 - 16 2023 
 
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN    
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A      
SRN CALIF   A    N     IDAHO       A    A     NEVADA      A    N      
W MONTANA   A    A     E MONTANA   A    N     WYOMING     A    N      
UTAH        A    N     ARIZONA     A    N     COLORADO    A    N      
NEW MEXICO  A    N     N DAKOTA    A    N     S DAKOTA    A    N      
NEBRASKA    A    N     KANSAS      A    N     OKLAHOMA    A    N      
N TEXAS     A    N     S TEXAS     A    N     W TEXAS     A    N      
MINNESOTA   A    N     IOWA        A    N     MISSOURI    A    N      
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   A    N      
ILLINOIS    A    N     MISSISSIPPI A    N     MICHIGAN    A    N      
INDIANA     A    N     OHIO        N    N     KENTUCKY    N    N      
TENNESSEE   N    N     ALABAMA     N    N     NEW YORK    A    N      
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N      
MASS        A    N     CONN        N    N     RHODE IS    N    N      
PENN        N    N     NEW JERSEY  N    N     W VIRGINIA  N    N      
MARYLAND    N    N     DELAWARE    N    N     VIRGINIA    N    N      
N CAROLINA  N    N     S CAROLINA  N    N     GEORGIA     N    N      
FL PNHDL    N    A     FL PENIN    N    A     AK N SLOPE  B    N      
AK ALEUTIAN B    B     AK WESTERN  B    B     AK INT BSN  B    N      
AK S INT    B    N     AK SO COAST B    N     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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