289
FXUS06 KWBC 301916
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed July 30 2025

6-10 DAY OUTLOOK FOR AUG 05 - 09 2025

The ECMWF, GEFS and Canadian ensemble models broadly agree on the 500-hPa
height pattern over North America and surrounding regions during the 6-10 day
period, with only minor variations among the models in terms of amplitude and
phase of predicted wave features. The manual height blend is based on 0Z
ensemble means, weighing the ECMWF model greater due to recent model anomaly
correlation skill. The manual blend shows a mid-level trough across the eastern
Bering Sea and Aleutians, accompanied by near to below normal heights. Weak
mid-level troughs are depicted over the northwestern and portions of the
eastern Contiguous U.S. (CONUS). The eastern trough is associated with near
normal heights over the Southeast, with positive height anomalies increasing
northward from the Great Lakes and Northeast to a broad anomalous ridge
centered over eastern Canada. A 594-dm height contour is predicted over the
southwestern and south-central CONUS. A moderately amplified (60-90 meters
above normal) anomalous ridge is depicted on the manual height blend to be
centered over the far eastern Pacific near 42N/140W.

Above normal temperatures are favored for Mainland Alaska, and near to slightly
below normal temperatures are favored for the Alaska Panhandle and Aleutians,
supported by the reforecast guidance. Above normal temperatures are favored for
western Oregon, California, western and southern Nevada, the Four Corners
region, Wyoming, and most of the Plains. Above normal temperatures are favored
to continue east of there across the Mississippi Valley and most of the Eastern
CONUS, with the exception of near normal temperatures favored over portions of
the southern Mid-Atlantic and interior Southeast. This widespread area of
favored anomalous warmth is attributed to mid-level ridging and/or low-level
southerly flow. Below normal temperature chances are elevated for an area
centered on the Northern Intermountain region, tied to mid-level troughing.
Above normal temperatures are likely for Hawaii, consistent with the automated
and consolidated tools.

Below normal precipitation is favored for northwestern parts of Mainland Alaska
related to drier easterly flow, while above normal precipitation is favored for
most other areas of the state, consistent with the precipitation consolidation
of calibrated model precipitation forecasts. This anomalous wetness is due to
moist onshore flow associated with broad low pressure over the Aleutians. For
the CONUS, above normal precipitation is favored from the Pacific Northwest
eastward over the Northern Intermountain region, Northern Rockies, and Northern
Plains, associated with a mid-level trough that is predicted to slowly weaken
as it moves eastward over this area. From there, chances are slightly tilted
towards above normal precipitation across the Upper Mississippi Valley, and for
most areas east of the Mississippi River, in an environment dominated by
southerly return flow from the Gulf and any weak frontal boundaries that
enhance low-level convergence. Below normal precipitation is favored from the
Central and Southern Intermountain region eastward to the Central and Southern
Plains, under a strong subtropical ridge and is well removed from the main
storm track. Near to below normal precipitation is also favored over parts of
the Northeast, under positive 500-hPa height anomalies. Above normal
precipitation is favored for Hawaii, consistent with the consolidation.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 40% 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 between ensemble models on the mid-level height pattern
forecast, offset by some differences among temperature and precipitation
forecast tools.

8-14 DAY OUTLOOK FOR AUG 07 - 13 2025

Ensemble mean forecasts for the 500-hPa circulation pattern over North America
remain in general agreement during the 8-14 day period, while the overall
pattern deamplifies. Differences from the earlier 6-10 day period include a
ridge over the north-central Pacific building across the western Bering Sea,
and slight eastward progression of the trough over the Aleutians and positive
height anomaly over the far eastern Pacific. The forecast pattern over the
CONUS favors above normal heights. However, predicted positive height anomalies
are weak over the Northern Plains and over southeastern or south-central
portions of the CONUS. This latter feature is of particular interest in August,
as this represents a weakness in the subtropical ridge, leaving the Gulf region
vulnerable to any tropical cyclone activity.

Above normal temperature chances are elevated for most of Alaska south of the
Brooks Range, consistent with the ECENS and GEFS reforecast temperature tools.
Near to slightly below normal temperatures are favored over the North Slope and
the Alaska Panhandle as indicated by todays auto temperature forecast. Farther
south, nearly all of the CONUS is favored to have above normal temperatures
during week-2, based on widespread mid-level ridging, positive 500-hPa height
departures, and broad southerly flow from the Gulf. The small-scale exception
is over parts of the Northern Rockies, where many tools predict near or even
below normal temperatures, probably related to a weakened mid- level trough.
Above normal temperatures are favored for Hawaii, supported by the consolidated
and automated temperature tools.

Below normal precipitation remains favored for much of the Southwest, extending
northward across eastern Idaho and western Wyoming based on the consolidation
and various raw precipitation tools. Above normal precipitation is slightly
favored for the Pacific Northwest, parts of the Northern Intermountain region,
northwestern California, and over southern Texas and most of the Florida
Peninsula. This is based on the consolidated and automated precipitation tools.
Odds slightly favor wetter-than-normal conditions from eastern North Dakota and
much of the Upper and Middle Mississippi Valley eastward across the Great Lakes
region and Ohio Valley to the Atlantic Coast from Maine to North Carolina. This
is consistent with many of the tools. In Alaska, continued onshore flow favors
above normal precipitation for much of the state, with the exception of near
normal precipitation for western and northwestern parts of Alaska, which is
more removed from the influence of onshore flow elsewhere. Above normal
precipitation is also favored over the Hawaiian Islands, warranted by the
automated precipitation tool.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 40% 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: Near average, 3 out of 5, due to
good overall agreement on the mid-level height forecast, offset by a
deamplifying pattern and weak signals in the precipitation tools for most areas.

FORECASTER: Anthony A

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
August 21.


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:
20010811 - 19600711 - 19880715 - 19530725 - 20030711


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:
20010809 - 19600712 - 19530724 - 20030711 - 19880715


6-10 DAY OUTLOOK TABLE
Outlook for Aug 05 - 09 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      N    A     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       B    B     NEVADA      N    B
W MONTANA   B    A     E MONTANA   N    A     WYOMING     A    B
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    A
NEBRASKA    A    N     KANSAS      A    B     OKLAHOMA    A    B
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    B
MINNESOTA   A    A     IOWA        A    N     MISSOURI    A    N
ARKANSAS    A    N     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   N    A     ALABAMA     N    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    A     W VIRGINIA  A    A
MARYLAND    A    A     DELAWARE    N    A     VIRGINIA    N    A
N CAROLINA  N    A     S CAROLINA  N    A     GEORGIA     N    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  A    N
AK ALEUTIAN N    A     AK WESTERN  A    N     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    B    A



8-14 DAY OUTLOOK TABLE
Outlook for Aug 07 - 13 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   N    N     E MONTANA   A    N     WYOMING     A    N
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B
NEW MEXICO  A    B     N DAKOTA    A    N     S DAKOTA    A    N
NEBRASKA    A    N     KANSAS      A    B     OKLAHOMA    A    B
N TEXAS     A    N     S TEXAS     A    N     W TEXAS     A    B
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        A    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    N     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    N
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    N     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN N    N     AK WESTERN  A    N     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    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.

$$