087
FXUS06 KWBC 091902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Wed April 09 2025

6-10 DAY OUTLOOK FOR APR 15 - 19 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 amplified mid-level height
pattern across the north-central Pacific, with a gradual eastward shift of
ridging from eastern Russia to the Bering Sea and troughing over the Gulf of
Alaska. Ridging and positive 500-hPa height anomalies are generally favored
across the western and southeastern Contiguous United States (CONUS), with
another shortwave trough and below normal 500-hPa heights over the northeastern
CONUS. Above-normal heights are forecast across the Aleutians and northern
Mainland Alaska. Slightly below-normal 500-hPa heights are predicted across
Hawaii.

Enhanced probabilities of above-normal temperatures are favored across much of
the western and central CONUS  underneath predominant ridging and above normal
500-hPa heights, supported by most of the dynamical guidance. The strongest
probabilities (>70%) are forecast across portions of Nevada and California.
Above-normal temperatures are slightly favored across parts of  the Southern
Plains and Florida due to the above normal 500-hPa heights. Below-normal
temperatures are most likely over the northeastern CONUS in association with
the below-normal 500hPa heights and troughing. The ridge-trough placement and
progression across Alaska favors elevated odds for below-normal temperatures
for parts of the western Mainland and Southeast Alaska, with above-normal
temperatures across the northeastern Mainland and the Aleutians. Above-normal
temperatures are forecast for Hawaii, consistent with the reforecast
consolidation tool.

Surface high pressure building behind a departing frontal system favors
enhanced chances of below-normal precipitation across Florida. Conversely,
shortwave troughing favors elevated near- to above-normal precipitation chances
extending from the Southern Plains to the Great Lakes and Northeast with
potential for a surface low to develop by the end of the period. Below-normal
precipitation probabilities are enhanced across the West tied to increasing
positive height anomalies and supported by the GEFS and ECENS reforecast tools.
Shortwave troughing progressing into the Gulf of Alaska favors enhanced
southerly flow, and subsequent increased probabilities for above-normal
precipitation for much of central and eastern Mainland and Southeast Alaska.
Near- to below-normal precipitation chances are increased across the portions
of southwestern Mainland Alaska and Aleutians behind the trough. Above-normal
precipitation is slightly favored in Hawaii with better agreement among model
guidance.

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. Good
agreement among the dynamical and statistical tools is offset by a progressive
pattern.

8-14 DAY OUTLOOK FOR APR 17 - 23 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. Ridging is forecast across much of the
western CONUS, with troughing persisting across northeastern North America.
Troughing initially forecast across the Gulf of Alaska is predicted to weaken
with ridging and positive height anomalies overspreading much of Alaska during
the period. The week-2 manual 500-hPa height blend depicts near-to slightly
below-normal heights over the Great Lakes and Northeast, with above-normal
heights forecast over the remainder of the CONUS. Above-normal heights are
favored for most of Alaska, with the largest positive height anomalies (+150
meters) centered across the Aleutians. Slightly below-normal 500-hPa heights
are forecast across Hawaii.

Probabilities for above-normal temperatures are increased over much of the
western half of the  CONUS during week-2 tied to a tendency toward more
ridging, with the highest probabilities (greater than 60 percent) over the
Great Basin. Below-normal temperatures chances are elevated across much of the
eastern CONUS tied to a stronger cold signal in the uncalibrated guidance, and
the potential for enhanced backdoor cold front activity given the negative
height anomaly center across southeastern Canada. A variable temperature
pattern is forecast across Alaska with the eastward shifting ridging favoring
more mid-level northerly flow across western Mainland Alaska near- to
below-normal temperature probabilities elevated over the region. Weak
probabilities for above-normal temperatures are favored for parts of the
Aleutians. In Hawaii, above-normal temperatures continue to be likely.

Signals are generally weak for precipitation across the U.S. during week-2,
with shortwave troughing potentially serving as a focus for a surface low track
across the Southern Plains through the Great Lakes and Northeast where weak
probabilities for above-normal precipitation are posted. The GEFS and ECENS
reforecast tools support enhanced chances for below-normal precipitation across
the western CONUS underneath more influence from surface high pressure, and
also supported by the analogs. Near- to above-normal precipitation chances are
elevated across Alaska and Hawaii.

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
continued good model agreement, offset by decreasing amplification and lack of
robust synoptic features in the guidance.

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
April 17.


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:
19980419 - 20080324 - 19600407 - 19620413 - 19770407


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:
20080323 - 19600406 - 19620416 - 19560324 - 19980419


6-10 DAY OUTLOOK TABLE
Outlook for Apr 15 - 19 2025

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



8-14 DAY OUTLOOK TABLE
Outlook for Apr 17 - 23 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    B     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    B     IDAHO       A    B     NEVADA      A    B
W MONTANA   A    B     E MONTANA   A    N     WYOMING     A    B
UTAH        A    B     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    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   N    N     IOWA        A    N     MISSOURI    N    A
ARKANSAS    N    A     LOUISIANA   N    N     WISCONSIN   N    N
ILLINOIS    N    A     MISSISSIPPI N    N     MICHIGAN    B    A
INDIANA     B    A     OHIO        B    A     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    A     NEW JERSEY  B    N     W VIRGINIA  B    A
MARYLAND    B    A     DELAWARE    B    N     VIRGINIA    B    N
N CAROLINA  B    N     S CAROLINA  B    N     GEORGIA     N    N
FL PNHDL    N    N     FL PENIN    A    N     AK N SLOPE  N    A
AK ALEUTIAN N    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.

$$