476
FXUS06 KWBC 081901
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Thu May 08 2025

6-10 DAY OUTLOOK FOR MAY 14 - 18 2025

Today`s model solutions are 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 primarily on the
ensemble means from the GEFS, ECMWF and Canadian models due to recent model
skill. The resultant manual blend features an anomalous trough and below normal
500-hPa heights over the Davis Strait extending southward to offshore of
Atlantic Canada. A strong mid-level anomalous ridge and above normal 500-hPa
height is forecast across the northeastern Contiguous United States (CONUS). A
trough and below-normal 500-hPa heights are forecast over most of the western
CONUS. The pattern for Alaska is forecast to be slow-moving such that by the
end of the period, the trough over the Bering Sea is predicted to essentially
remain in place. Slightly above normal 500-hPa heights are predicted across
Hawaii.

Above normal temperatures are likely for most of the eastern and central CONUS
due to a combination of anomalous ridging over the northeastern CONUS and
southerly flow across the Plains and Mississippi Valley. The highest likelihood
of unseasonable warmth is across portions of the northeastern CONUS, near the
center of the predicted mean ridge. Near to below normal temperatures are
likely for the western CONUS as a strong trough is forecast to progress
eastward across the region during the period, supported by most of the
dynamical temperature forecast tools. A slight tilt toward above normal
temperatures is indicated for southwestern Alaska and the Aleutians ahead of
the Bering Sea trough. Above normal sea surface temperatures (SSTs) in nearby
waters may also contribute to increasing chances of above normal temperatures
for this region. Below normal temperatures are favored for parts of
northeastern Mainland Alaska consistent with predicted below normal heights and
for Southeast Alaska underneath anomalous northerly mid-level flow. Near normal
temperatures are favored for the remainder of the state due to weak or
conflicting guidance. Above normal temperatures are likely across Hawaii
consistent with anticipated above normal sea surface temperatures (SSTs) in
adjacent waters.

An active period is anticipated across much of the western CONUS as an
anomalous trough pushes eastward over the Interior West during the period. As
the trough progresses eastward, enhanced above normal precipitation
probabilities are forecast across much of the central and eastern CONUS as
southerly flow increases. Above normal precipitation is also likely for the
coastal Southeast and Mid-Atlantic as a slow moving low pressure system is
expected to promote ample moisture advection into this region from the Gulf and
Atlantic. Below normal precipitation is more likely across parts of southern
Texas, supported by most of the dynamical precipitation forecast tools. Above
normal precipitation is favored across most of southern and central Alaska due
to persistent anomalous troughing predicted over the Bering Sea, while below
normal precipitation is likely over parts of  northern Mainland Alaska. Above
normal precipitation is also favored for Hawaii, consistent with skill weighted
calibrated precipitation amounts calculated from the GEFS and ECMWF ensembles.

The official 6-10 day 500-hPa height blend consists of 30% of Today`s 6z 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 among todays ensemble means.


8-14 DAY OUTLOOK FOR MAY 16 - 22 2025

Ensemble mean solutions for the 8-14 day period predict a fairly consistent
500-hPa circulation pattern relative to the 6-10 day period across North
America and the surrounding regions. The week-2 period features anomalous
ridging and above normal 500-hPa height over the North Pacific Ocean extending
eastward to the West Coast. The trough over the Bering Sea is forecast to
gradually reduce in intensity. The trough over the western CONUS is forecast to
progress eastward and weaken with time. The ridge over the Great Lakes is
generally forecast to lift northeastward with heights returning to near normal
in its wake across much of the East during the latter half of the period.
Generally near to slightly below normal 500-hPa heights are forecast for
Hawaii, well to the south of a mean ridge forecast across the eastern Pacific.

Above normal temperatures are favored for most of the eastern CONUS and Texas,
due to a combination of anomalous ridging and southerly flow. However,
relatively modestly enhanced probabilities of above normal temperatures are
indicated for parts of  the Southeast and Mid-Atlantic coast as confidence is
tempered in the wake of a departing low pressure system early in the period.
Cooler than normal temperatures are favored for parts of the High Plains and
the Rockies due to troughing, particularly early in the period. However, above
normal temperatures are more likely for portions of California and Nevada under
ridging and  above normal 500-hPa heights. A slight tilt toward below normal
temperatures is indicated for parts of northeastern Alaska associated with
nearby Arctic surface high pressure to the north, while above normal
temperatures are- modestly favored  over the Aleutians and parts of the
southwestern Mainland Alaska.. Above normal temperatures remain likely across
Hawaii associated with anticipated above normal SSTs in adjacent waters.

An active pattern is anticipated to continue into week-2 for much of the CONUS
due to a predicted trough and increased southerly flow, consistent with most of
the dynamical precipitation forecast tools. Below normal precipitation is more
likely across northern and central California, northwestern Nevada, and
southern Florida under ridging and above normal 500-hPa heights. An active
pattern and increased above normal precipitation chances remain forecast for
much of southern and central Alaska due to persistent troughing over the State.
Above normal precipitation is also favored for Hawaii, consistent with skill
weighted calibrated precipitation amounts calculated from the GEFS and ECMWF
ensembles.

The official 8-14 day 500-hPa height blend consists of: 30% of Today`s 6z 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: Average, 3 out of 5, due to a
predicted amplified pattern early in period offset by a potential moderation of
the pattern and increased uncertainty later in week-2.


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 May
15.


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:
19570428 - 19880521 - 20060428 - 19800519 - 19870421


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:
19780516 - 19870421 - 20060426 - 19880521 - 19700517


6-10 DAY OUTLOOK TABLE
Outlook for May 14 - 18 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      B    N     NRN CALIF   N    N
SRN CALIF   B    N     IDAHO       B    A     NEVADA      B    A
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        B    A     ARIZONA     B    N     COLORADO    B    A
NEW MEXICO  B    N     N DAKOTA    A    A     S DAKOTA    A    A
NEBRASKA    A    A     KANSAS      A    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    B     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    N     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    N
MASS        A    A     CONN        A    A     RHODE IS    A    A
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  A    N     GEORGIA     A    N
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  N    B
AK ALEUTIAN A    A     AK WESTERN  N    A     AK INT BSN  N    A
AK S INT    N    A     AK SO COAST N    A     AK PNHDL    B    A



8-14 DAY OUTLOOK TABLE
Outlook for May 16 - 22 2025

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

$$