607
FXUS06 KWBC 131901
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed August 13 2025

6-10 DAY OUTLOOK FOR AUG 19 - 23 2025

Today`s model solutions continue to be in good agreement on the predicted
500-hPa circulation pattern across North America and surrounding regions during
the 6-10 day period. The manual 500-hPa height blend is based on the ensemble
means from the GEFS, ECMWF and Canadian models. The resultant manual blend
features amplified ridging over the eastern Bering Sea and moderate troughing
downstream over the North Pacific, broad ridging over most of the Contiguous
U.S. (CONUS) and troughing over Quebec, extending into the Northeast and
adjacent North Atlantic. Todays model solutions continue to stretch negative
height anomalies further south along the East Coast, adding confidence to the
cooling trend seen in model guidance for the northeastern quarter of the CONUS.

Expansive positive 500-hPa height anomalies over much of North America broadly
favors above-normal temperatures for much of the CONUS, with probabilities of
at least 40% almost universal from the West Coast to the Mississippi Valley and
Southeast.  Higher probabilities of above-normal temperatures are forecast
along the Gulf Coast and up the Lower Mississippi Valley (>50%), and especially
for the Great Basin, Rockies and High Plains, with peak probabilities exceeding
70% over the northern Great Basin. Chances of above-normal temperatures weaken
along the northern West Coast and for the northeastern CONUS, with near-normal
temperatures most likely for the Seattle area, and portions of the Upper
Mississippi Valley, the Ohio Valley, Central Appalachians, and the Mid-Atlantic
states, while below-normal temperatures become more likely for the Northeast
U.S. and eastern portions of the Great Lakes as the Quebec trough becomes
deeper. Amplified ridging over the eastern Bering Sea favors above-normal
temperatures for much of Mainland and Southeast Alaska, while lingering
troughing upstream over the Chukchi Sea favors near- to below-normal
temperatures for the North Slope. Continued positive sea surface temperature
anomalies near Hawaii favor persistent above-normal temperatures for the state.

Troughing over the North Pacific favors near or above-normal precipitation
along the U.S.-Canada border from the West Coast to the Northern Plains.
Monsoon activity also tilts the odds towards above-normal precipitation for
portions of the Desert Southwest and Rockies. Increased moisture off the Gulf
of America spreading north is also indicated by model guidance, tilting
portions of the Southern Plains, Southeast U.S., and Mid-Atlantic towards
above-normal precipitation. Tropical Storm (TS) Erin, which formed just west of
the Cape Verde islands on Aug 11 is moving generally westward and is favored to
approach the East Coast then turn to move parallel to the coast. While the
exact track of Eric cannot be determined at this time, troughing over Quebec
has the potential to interact with the wind field of Erin as depicted by model
solutions, resulting in dry northwesterly flow and pushing the odds towards
below-normal precipitation for portions of the Great Lakes and New England.
Model guidance indicates the storm track off the North Pacific situated over
the Canadian Pacific coast, resulting in below-normal precipitation for
portions of the northwestern CONUS. In Alaska, troughing over the Chukchi Sea
favors above-normal precipitation for much of the Alaskan Mainland, however
ridging over the Bering Sea prevents southward spread of this enhanced
moisture, tilting the southern coast towards below-normal precipitation.

The official 6-10 day 500-hPa height blend consists of 33% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 34% of Today`s 0z European Ensemble Mean
centered on Day 8, and 33% 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. Very
good agreement among the temperature and precipitation dynamical and
statistical tools is offset by uncertainty surrounding the tropics

8-14 DAY OUTLOOK FOR AUG 21 - 27 2025

Ensemble mean solutions for the 8-14 day period predict the amplified pattern
seen in the 6-10day period to flatten out somewhat, due mostly to deformation
and weakening of the troughs over the North Pacific and Quebec. Strong ridging
remains in place over the eastern Bering Sea and over the southwestern CONUS.
The troughing feature over the Chukchi Sea is favored to weaken but remain,
while model ensembles depict the trough over Quebec weakening slightly but
broadening, resulting in a noticeable shift in temperatures for much of the
eastern CONUS.

Models favor the Quebec trough to broaden, which along with potential
large-scale influence from TS Erin, results in portions of the eastern CONUS
being favored to shift from above-normal temperatures during the 6-10 day
period to near-normal for week-2, with a slight tilt towards below-normal
temperatures spreading into the Upper Mississippi, Great Lakes, and
Mid-Atlantic regions. Above-normal temperatures continue to be favored across
the western half of the Lower 48 and along the Gulf Coast, with probabilities
exceeding 50% for most of the Lower 48 west of the Rockies. For Alaska the
persistent upper-level pattern results in a mostly persistence forecast,
although weakening troughing over the Chukchi Sea allows for a slight shift
northward for enhanced above-normal temperature probabilities. Similarly, the
Hawaii forecast is little changed from the 6-10 day period with no changes in
temperature forcing in the region.

Monsoon moisture is favored to continue spreading into the southwestern CONUS,
slightly tilting the odds towards above-normal precipitation from the Desert
Southwest up into the Central Rockies. Models depict Pacific moisture moving
over the top of the CONUS ridge and along the U.S.-Canada border, slightly
favoring above-normal precipitation for portions of the Northern Plains as
well. Tropical moisture could also play a role in the week-2 precipitation
outlook as the Atlantic TC season picks up, resulting in a modest tilt towards
above-normal precipitation for the Gulf Coast and Southeastern U.S. Similar to
the 6-10 day period, large-scale interactions with Erin and the Quebec trough
would tend to lower the potential for precipitation for the northeastern CONUS,
resulting in near- to below-normal precipitation indicated from New England
south to Chesapeake Bay and westward as far as the Central Plains. As the week
progresses the tropics will be closely monitored for potential impacts from any
developing systems.

The official 8-14 day 500-hPa height blend consists of: 33% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 34% of Today`s 0z European Ensemble Mean
centered on Day 11, and 33% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: About average, 3 out of 5. Good
agreement among the temperature and precipitation dynamical and statistical
tools is offset by the likelihood of tropical cyclone activity in the Atlantic
during week-2.

FORECASTER: Daniel Barandiaran

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:
19880802 - 19960806 - 19810726 - 20020813 - 19620827


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:
19620826 - 19880801 - 20020813 - 19810728 - 19960805


6-10 DAY OUTLOOK TABLE
Outlook for Aug 19 - 23 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N
W MONTANA   A    N     E MONTANA   A    A     WYOMING     A    A
UTAH        A    N     ARIZONA     A    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    A    A     S DAKOTA    A    A
NEBRASKA    A    A     KANSAS      A    N     OKLAHOMA    A    N
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    N
MINNESOTA   A    N     IOWA        N    N     MISSOURI    A    N
ARKANSAS    A    N     LOUISIANA   A    N     WISCONSIN   N    N
ILLINOIS    A    N     MISSISSIPPI A    A     MICHIGAN    B    B
INDIANA     A    N     OHIO        N    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    A     NEW YORK    B    N
VERMONT     B    N     NEW HAMP    B    N     MAINE       B    N
MASS        B    N     CONN        B    A     RHODE IS    B    A
PENN        B    N     NEW JERSEY  B    A     W VIRGINIA  N    N
MARYLAND    B    A     DELAWARE    B    A     VIRGINIA    B    A
N CAROLINA  N    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  N    A
AK ALEUTIAN A    B     AK WESTERN  A    A     AK INT BSN  N    A
AK S INT    A    B     AK SO COAST A    B     AK PNHDL    A    B



8-14 DAY OUTLOOK TABLE
Outlook for Aug 21 - 27 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    N
W MONTANA   A    N     E MONTANA   A    A     WYOMING     A    A
UTAH        A    A     ARIZONA     A    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    N    A     S DAKOTA    N    A
NEBRASKA    A    A     KANSAS      A    N     OKLAHOMA    A    N
N TEXAS     A    N     S TEXAS     A    A     W TEXAS     A    N
MINNESOTA   B    N     IOWA        B    N     MISSOURI    N    N
ARKANSAS    N    N     LOUISIANA   A    A     WISCONSIN   B    N
ILLINOIS    B    B     MISSISSIPPI A    A     MICHIGAN    B    B
INDIANA     B    B     OHIO        B    B     KENTUCKY    N    N
TENNESSEE   N    N     ALABAMA     N    A     NEW YORK    B    B
VERMONT     B    N     NEW HAMP    B    N     MAINE       B    N
MASS        B    N     CONN        B    N     RHODE IS    B    N
PENN        B    N     NEW JERSEY  B    N     W VIRGINIA  B    N
MARYLAND    B    N     DELAWARE    B    N     VIRGINIA    N    N
N CAROLINA  N    A     S CAROLINA  A    A     GEORGIA     A    A
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    A
AK ALEUTIAN A    B     AK WESTERN  A    A     AK INT BSN  A    A
AK S INT    A    N     AK SO COAST A    B     AK PNHDL    A    B

                           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.

$$