530
FXUS06 KWBC 311909
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Thu July 31 2025

6-10 DAY OUTLOOK FOR AUG 06 - 10 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 moderately amplified anomalous
ridge over the Bering Sea and a mid-level trough accompanied by near to below
normal heights across the Aleutians. A weak mid-level trough is depicted over
the northwestern Contiguous U.S. (CONUS). Positive 500-hPa height anomalies are
forecast over most of the CONUS. A broad anomalous ridge is centered over
eastern Canada. Slightly above-normal 500-hPa heights are predicted across
Hawaii.

Above normal temperatures are favored for most of l Mainland Alaska, while near
to slightly below normal temperatures are favored over the North Slope and the
Alaska Panhandle, supported by todays GEFS and ECMWF calibrated reforecast
tools. Below normal temperature chances are elevated in northeastern
Washington, Northern Idaho, and western Montana, tied to mid-level troughing.
Near to above normal temperatures are favored over the remainder of the CONUS,
This widespread area of favored anomalous warmth is attributed to mid-level
ridging and/or low-level southerly flow. Above normal temperatures are likely
for Hawaii, under above normal 500-hPa height, consistent with the automated
and consolidated temperature forecast tools.

Above normal precipitation is favored for the Alaska Peninsula , southern
coast, and eastern parts of Mainland Alaska, 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 most
of the eastern CONUS, 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 08 - 14 2025

Ensemble mean forecasts for the 500-hPa circulation pattern over North America
remain in general agreement during the 8-14 day period. In the manual blend of
model forecasts, a ridge and positive 500-hPa height anomalies is forecast over
the Bering Sea. The mid-level trough and associated negative 500-hPa height
anomalies over the Aleutian Islands remain in the week-2 forecast, but with
slight eastward progression. Positive 500-hPa height anomalies are forecast
over most of the CONUS. The broad anomalous ridge forecast over eastern Canada
during the 6-10 day period deamplifies. Slightly above-normal 500-hPa heights
are predicted across Hawaii.

Above normal temperature chances are elevated for parts of southeastern
Mainland Alaska, while slightly below normal temperatures are favored over
portions of  northern Mainland Alaska, 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,
supported by most of the dynamical temperature forecast tools. Above normal
temperatures are favored for Hawaii, supported by the consolidated and
automated temperature tools.

Below normal precipitation is favored across parts of the Four Corners Region
under above normal 500-hPa heights. Above normal precipitation is slightly
favored for the Pacific Northwest, parts of the Northern Intermountain region,
California, southwestern Arizona, and most of eastern CONUS. This is based on
the consolidated and automated precipitation tools. In Alaska, continued
onshore flow favors above normal precipitation for nearly all of the state.
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: Luke 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
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:
19600712 - 20010812 - 19880715 - 19980730 - 20010807


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:
20010811 - 19600713 - 19880716 - 19980730 - 20030711


6-10 DAY OUTLOOK TABLE
Outlook for Aug 06 - 10 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    A     OREGON      A    A     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       N    B     NEVADA      A    B
W MONTANA   N    A     E MONTANA   A    N     WYOMING     A    B
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    N
NEBRASKA    A    N     KANSAS      A    B     OKLAHOMA    A    B
N TEXAS     A    B     S TEXAS     A    N     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    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  N    A     GEORGIA     N    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  B    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



8-14 DAY OUTLOOK TABLE
Outlook for Aug 08 - 14 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A
SRN CALIF   A    A     IDAHO       A    N     NEVADA      A    N
W MONTANA   A    N     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    A
INDIANA     A    A     OHIO        A    N     KENTUCKY    A    N
TENNESSEE   A    N     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    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  B    A
AK ALEUTIAN N    N     AK WESTERN  N    A     AK INT BSN  N    A
AK S INT    A    A     AK SO COAST A    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.

$$