491
FXUS06 KWBC 131902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue May 13 2025

6-10 DAY OUTLOOK FOR MAY 19 - 23 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 mid-level ridge and
above-normal heights over the Eastern Pacific extending eastward to the west
coast of the Contiguous United States (CONUS). A mid-level trough is forecast
over the north-central CONUS extending southwestward to the Southern Rockies,
while a ridge and above-normal 500-height are predicted across the southeastern
CONS. Troughing is also forecast across Alaska, extending into the Gulf of
Alaska, with associated negative 500-hPa height anomalies across the state.
Slightly below-normal  500-hPa heights are predicted across Hawaii.

Below-normal temperatures are favored over most of the northern CONUS as well
as portions of the Four Corners region with troughing stretched across the
Northern Tier. Probabilities exceed 60% for portions of the Northern Plains
and the Upper Mississippi Valley. Above-normal temperatures are slightly
favored over parts of the West Coast and more strongly favored for the southern
CONUS east of the Rockies, under positive 500-hPa height anomalies. Chances of
above-normal temperatures increase from north to south, exceeding 70% in
southern Texas and portions of the Southeast. Under predicted negative 500-hPa
height anomalies, below-normal temperatures are likely over northern Alaska and
Southeast Alaska, while slightly above-normal temperatures are favored for
parts of the southwestern Mainland Alaska, consistent with the reforecast
consolidation temperature forecast tool. Above-normal temperatures are likely
for Hawaii, with positive sea surface temperature anomalies surrounding the
Islands.

Above-normal precipitation is slightly favored for much of the Northern and
Central Rockies as well as most points east, ahead of predicted troughing.
Probabilities are slightly enhanced (>40%) for most of the north-central CONUS
where precipitation is forecast to be enhanced by Gulf moisture inflow.
Below-normal precipitation is favored across much of the West Coast with
amplified ridging upstream over the Eastern Pacific, as well as the Florida
Peninsula where surface high pressure is favored. Above-normal precipitation is
favored for most of central and eastern Alaska, with a predicted trough and
southerly flow, while below-normal precipitation is favored for portions of the
southwestern Mainland Alaska and the Alaska Peninsula, supported by most of the
dynamical precipitation forecast tools. Precipitation consolidation tool
forecasts favor above-normal precipitation for Hawaii.

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. Very
good agreement among the temperature and precipitation dynamical and
statistical tools is offset by differences in ensemble mean 500-hPa height
anomalies.

8-14 DAY OUTLOOK FOR MAY 21 - 27 2025

Ensemble mean solutions for the 8-14 day period predict a progressive and
de-amplified 500-hPa circulation pattern relative to the 6-10 day period across
North America and the surrounding regions. Ridging over the Eastern Pacific is
favored to weaken, but also spread into the western CONUS, while a mid-level
trough is forecast over the Great Lakes region. Large positive height anomalies
over the Canadian Maritimes help to flatten out upper-level flow, resulting in
a very zonal pattern over the CONUS. Weak troughing continues over Alaska, with
an amplified ridge upstream over the Bering Sea. 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 continue to be favored across most of the southern
and southwestern CONUS in the week-2 period, under ridging and positive 500-hPa
height anomalies. Probabilities exceed 50% for the Florida Peninsula and
portions of the southwestern CONUS as well as southern Texas, where positive
height anomalies are greatest. Below-normal temperatures are favored for the
northeast quarter of the CONUS under persistent troughing. Forecast tools also
indicate a slight tilt towards below-normal temperatures for portions of the
Pacific Northwest. Above-normal temperatures are favored for portions of
southern Alaska, while below-normal temperatures are indicated over much of
northern Alaska, consistent with most of the dynamical temperature forecast
tools. Above-normal temperatures are predicted to persist across Hawaii during
week-2 by dynamical models.

Near- to above-normal precipitation is slightly favored for much of the eastern
CONUS (except for Florida, where below-normal precipitation is indicated) and
parts of the Southern Plains, supported by most dynamical model precipitation
forecast tools. Near- to below-normal precipitation is slightly favored over
the western CONUS, under mean positive 500-hPa height anomalies. Above-normal
precipitation is favored for most Alaska under persistent troughing, while
near-normal precipitation is forecast over the western Aleutians. Above-normal
precipitation is favored for Hawaii during the week-2 period, 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: About average, 3 out of 5. Good
agreement among the temperature and precipitation dynamical and statistical
tools is offset by weak ensemble mean 500-hPa height anomalies.

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:
19910527 - 19780523 - 19880527 - 19570423 - 19740423


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:
19910526 - 19780522 - 19570422 - 19740422 - 19770502


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

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



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

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

                           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.

$$