427
FXUS06 KWBC 052027
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue August 05 2025

6-10 DAY OUTLOOK FOR AUG 11 - 15 2025

Today`s ensemble mean solutions generally depict a positive NAO pattern with
near to below normal heights dominating much of the higher latitudes of the
western Hemisphere, particularly early in the period. As time progresses,
troughing over Greenland weakens but a trough over Alaska remains firmly
established. Farther to the south, off the West Coast of the CONUS, above
normal heights are predicted to retrograde. This forecast ridge retrogression
supports a decrease in heights downstream over the Pacific Northwest and
Northern Rockies and an increase in heights farther to the east across the
northern and central Plains. A strong subtropical ridge is forecast across the
Southwest early in the period but weakens fairly rapidly as time progresses.
Farther to the north and east, strong ridging is forecast over Eastern Canada
with associated above normal heights stretching southward to the northeastern
quadrant of the CONUS. A weakness in the subtropical ridge is depicted farther
to the south, near the Lower Mississippi Valley early in the period. Tropical
storm Henriette, currently over the eastern Pacific, is forecast to pass to the
north of Hawaii but potentially close enough to influence sensible weather
across parts of the island chain.

Above normal temperatures are likely for the northeastern quadrant of the
CONUS, associated with the predicted ridge in Eastern Canada. Probabilities of
above normal temperatures exceed 80 percent across northern New England and
adjacent northeastern New York State. Enhanced probabilities of above normal
temperatures are much more modest over most of the Southeastern quadrant of the
CONUS, as predicted height anomalies are relatively weak and increased
cloudiness may keep maximum temperatures down. Above normal temperatures are
likely across the Southwest due to strong subtropical ridging early in the
period. Probabilities of above normal temperatures exceed 60 percent for most
of New Mexico and adjacent areas of western Texas. Near normal temperatures are
favored farther to the north, across parts of the northern Rockies, associated
with a predicted mid-level trough. Above normal temperatures are more likely
for the Pacific Northwest and Northern California due to strong ridging early
in the period. Below normal temperatures are likely for most of Alaska due to
persistent troughing. However, near normal temperatures are favored along much
of the South Coast, where predicted height anomalies are relatively weaker.
Above normal temperatures are likely for Hawaii associated with above normal
SSTs, especially for western portions of the island chain.

An active period is anticipated across Alaska as a trough is forecast to
persist across much of the Mainland. Probabilities of above normal
precipitation exceed 50 percent across Southeast Alaska and adjacent areas of
the southeastern Mainland, due to predicted onshore flow ahead of this trough.
Conversely, subtropical ridging favors below normal precipitation across much
of the Great Basin, eastward across the central Rockies and adjacent areas of
the central High Plains. As this subtropical ridge weakens later in the period,
this may allow monsoonal moisture to increase over southern Arizona, where
above normal precipitation is slightly favored. Above normal precipitation is
also favored across parts of the Northern Rockies and Plains associated with a
predicted trough. Onshore flow to the west of a surface high over the Atlantic
favors elevated chances of above normal precipitation for the Southeast.
Elevated above normal precipitation probabilities extend northward to the Great
Lakes, due to predicted frontal activity.  Conversely, strong ridging over
eastern Canada leads to increased chances of near  normal precipitation across
much of the Northeast and adjacent Mid-Atlantic. Above normal precipitation is
favored for central and western Hawaii, as nearby tropical storm Henriette may
promote increased moisture advection across parts of the island chain.

The official 6-10 day 500-hPa height blend consists of 25% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 50% of Today`s 0z European Ensemble Mean
centered on Day 8, and 25% 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 todays ensemble means.


8-14 DAY OUTLOOK FOR AUG 13 - 19 2025

The 500-hPa forecast for the week-2 period exhibits some of the same main
features as the preceding 6-10 day period. A strong trough is forecast to
persist across most of Alaska early in the period. However, models predict
increased heights over southwestern Alaska by the end of the period due, in
part, to a predicted retrogression of a ridge initially positioned off the
Pacific Northwest Coast. As this ridge retrogrades, height falls and associated
troughing are forecast over the West Coast as time progresses. As heights begin
to fall over the West, corresponding height rises and increased ridging are
predicted across much of the Plains. Above normal heights are forecast to
persist for the northeastern quadrant of the CONUS throughout the period. By
the beginning of week-2, subtropical ridging over the Southwest is predicted to
substantially weaken relative to the preceding 6-10 day period. The weakened
ridge center is then forecast to slowly migrate northward and eastward toward
the central Plains later in the period.

Above normal temperatures are likely across the northeastern quadrant of the
CONUS, due to strong and persistent ridging in adjacent eastern Canada.
Probabilities of above normal temperatures exceed 70 percent for the lower
Great Lakes and most of the Northeast. The likelihood of above normal
temperatures is forecast to increase farther to the west, across the Plains,
due to predicted increased ridging. Predicted height falls over the West Coast
significantly reduces above normal temperature chances relative to yesterday`s
outlook. As such, near normal temperatures are now more likely for much of the
Northern Rockies, Pacific Northwest, as well as southern and central California
and adjacent areas of western Arizona and southwestern Nevada. Above normal
temperatures are more likely for the Florida Peninsula, underneath predicted
low-level southeasterly flow and above normal SSTs in adjacent waters.
Conversely, below normal temperatures are favored for most of Alaska due to a
persistent trough. The exception is for parts of the South Coast, where
predicted mean height anomalies are more modest. Above normal temperatures are
favored for Hawaii, with the highest confidence across western and central
portions of the island chain.

An active pattern is anticipated to continue into week-2 for much of eastern
and central Alaska associated with persistent troughing. Near or below normal
precipitation is more likely across western parts of the state, associated with
predicted height rises later in the period. Above normal precipitation is
favored for the Pacific Northwest, Northern Rockies, and adjacent areas of the
Northern Plains, underneath predicted shallow cyclonic flow. Below normal
precipitation is more likely for most of the central Plains and parts of the
southern Plains as subtropical ridging migrates into the region from the
Southwest. As this subtropical ridge moves northeastward, increased monsoonal
moisture advection is possible for the Southwest, leading to elevated above
normal precipitation chances for Arizona and adjacent areas of eastern New
Mexico and southeastern California, northeastward across southeastern Utah and
western Colorado. Dry conditions are more likely for parts of western Nevada
and adjacent areas of California, farther away from the predicted monsoonal
moisture plume. Above normal precipitation chances are elevated for the Great
Lakes and Ohio Valley, consistent with teleconnections from forecast positive
height anomaly centers over both the northeastern Atlantic and the northeastern
Pacific. Above normal precipitation is also favored for the southeastern
quadrant of the CONUS due to potential enhanced moisture advection associated
with predicted southeasterly or southerly low-level flow. Above normal
precipitation is slightly favored for western Hawaii as an area of low pressure
is forecast to pass nearby early in the period.

The official 8-14 day 500-hPa height blend consists of: 25% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 50% of Today`s 0z European Ensemble Mean
centered on Day 11, and 25% 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 the 500-hPa pattern offset by weak precipitation signals
across much of the forecast domain.

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
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:
19970720 - 19820808 - 19530819 - 19980802 - 19890716


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:
19970719 - 19820808 - 19890719 - 19980802 - 19530818


6-10 DAY OUTLOOK TABLE
Outlook for Aug 11 - 15 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   N    A     E MONTANA   A    N     WYOMING     A    B
UTAH        A    B     ARIZONA     A    N     COLORADO    A    B
NEW MEXICO  A    N     N DAKOTA    A    N     S DAKOTA    A    N
NEBRASKA    A    N     KANSAS      A    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    N
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    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    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 N    A     AK WESTERN  B    A     AK INT BSN  B    A
AK S INT    B    A     AK SO COAST N    A     AK PNHDL    B    A



8-14 DAY OUTLOOK TABLE
Outlook for Aug 13 - 19 2025

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

$$