873
FXUS06 KWBC 011902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue April 01 2025

6-10 DAY OUTLOOK FOR APR 07 - 11 2025

The 0z GEFS, ECENS, and CMCE are in very good agreement regarding an amplified
500-hPa height pattern across North America. Troughing is forecast over the
eastern contiguous U.S. (CONUS), with ridging becoming established across the
western CONUS. Troughing initially forecast across central Alaska is predicted
to weaken, with ridging and positive height anomalies expanding over the state
by the end of the period. Todays manual 6-10 day 500-hPa height blend depicts
above-normal heights across much of the western CONUS, and below-normal heights
over the northeastern quadrant of the CONUS. The largest positive and negative
anomalies are indicated closer to the U.S./Canadian Border. Near-normal heights
are favored across the south-central and southeastern CONUS. Near- to slightly
below-normal heights are depicted over much of Mainland Alaska and the Alaska
Peninsula, with above-normal heights forecast over the western Aleutians, far
eastern Mainland, and Southeast Alaska.

Probabilities for below-normal temperatures are increased over much of the
central and eastern CONUS underneath increasing northerly mid-level flow behind
a frontal boundary predicted to move through at the outset of the period, with
the highest chances (greater than 80 percent) across the Lower Mississippi
Valley. There is some concern for early spring frosts or freezes across some
areas as relatively colder temperatures coincide with emerging vegetation.
Ridging forecast across the West favors elevated probabilities of above-normal
temperatures. Troughing predicted over central Mainland Alaska supports
increased chances for above-normal temperatures over the southern and eastern
parts of the state due to enhanced southerly flow. Conversely, below-normal
temperature chances are increased on the backside of the mean trough axis
across western Mainland. Increasing mid-level heights over the Aleutians
supports enhanced near- to above-normal temperatures chances. Above-normal
temperatures continue to be favored across Hawaii.

A frontal system is favored to quickly progress east at the outset of the
period. While above-normal precipitation probabilities are increased across
portions of the southeastern U.S., a broad area of enhanced below-normal
precipitation probabilities are forecast across much of the western CONUS and
building into the Great Plains and Midwest as surface high pressure becomes
established. Elevated probabilities for above-normal precipitation are favored
across eastern Alaska due to enhanced onshore flow ahead of troughing. Near- to
below-normal precipitation chances are increased across the far western
Mainland and the Aleutians underneath a more northerly mid-level flow pattern.
Above-normal precipitation is forecast across Hawaii supported by the
consolidation forecast tool.

The official 6-10 day 500-hPa height blend consists of 34% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 33% 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. Good
agreement with regard to overall synoptic picture, offset by stronger ridging
depicted in ECMWF and subsequent solutions offered by ECMWF-based tools.

8-14 DAY OUTLOOK FOR APR 09 - 15 2025

The 500-hPa height pattern predicted during week-2 is similar to that of the
6-10 day period, with minimal eastward progression and decreasing amplification
of features. The dynamical models remain in good agreement regarding ridging
(troughing) across the western (eastern) CONUS. The week-2 manual 500-hPa
height blend depicts below-normal heights for most areas east of the
Mississippi River, and above-normal heights upstream to the west. Weakly
above-normal heights are depicted across Alaska  underneath a weak trough
signature persisting across the central Mainland. Larger positive height
anomalies are forecast across the Aleutians and far western Mainland associated
with ridging centered across eastern Russia and the Bering Sea.

Below-normal temperature probabilities remain elevated across the eastern half
of the CONUS as well as the Southern Plains, with the greatest probabilities
(>60%) over portions of the southeastern U.S. Enhanced probabilities are
indicated for above-normal temperatures across the West, especially the Great
Basic (>70%), under the largest forecast positive 500-hPa height departures. As
the mean trough axis shifts to the east and weakens, warming temperatures are
forecast across the Northern and Central Plains resulting in an eastward
expansion of the enhanced above-normal temperature chances to include these
areas. Chances for above-normal temperatures remain across southern Alaska due
to continued southerly flow. A slight tilt toward below-normal temperatures is
favored over the western Mainland, supported by a teleconnection with the
upstream positive height anomaly center and enhanced northerly mid-level flow.
Increased probabilities for above-normal temperatures remain forecast across
Hawaii.

Ridging over the West, combined with surface high pressure over the East, favor
increased chances for below-normal precipitation over much of the CONUS, with
chances above 50 percent for portions of the Great Basin and Lower MIssissippi
Valley. Lingering frontal activity across the southern Florida Peninsula tilts
the odds toward above-normal precipitation supported by the ECENS and GEFS
reforecast tools, with near-normal precipitation favored along the immediate
East Coast from the Outer Banks northward tied to possible surface low
development later in the period. A slight tilt toward elevated odds for above
(below) normal precipitation remains favored across eastern (western) Mainland
Alaska underneath slightly enhanced southerly (northerly) mid-level flow
associated with weak troughing across the Central Mainland, although a much
drier signal is noted in the dynamical models across coastal southeastern
Alaska later in the period compared to earlier in the period. Above-normal
precipitation chances are increased across Hawaii.

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: Above average, 4 out of 5. Good
agreement with regard to overall synoptic picture, offset by stronger ridging
depicted in ECMWF and subsequent solutions offered by ECMWF-based tools.

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
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:
19970313 - 19670318 - 19630404 - 19900409 - 19630329


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:
19970313 - 19670318 - 19630403 - 19630328 - 19890312


6-10 DAY OUTLOOK TABLE
Outlook for Apr 07 - 11 2025

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    A     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    B     COLORADO    A    B
NEW MEXICO  A    B     N DAKOTA    A    B     S DAKOTA    A    B
NEBRASKA    A    B     KANSAS      N    B     OKLAHOMA    B    B
N TEXAS     B    B     S TEXAS     B    B     W TEXAS     B    B
MINNESOTA   N    B     IOWA        N    B     MISSOURI    B    B
ARKANSAS    B    B     LOUISIANA   B    B     WISCONSIN   B    B
ILLINOIS    B    B     MISSISSIPPI B    B     MICHIGAN    B    B
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    B
TENNESSEE   B    B     ALABAMA     B    N     NEW YORK    B    N
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    A     VIRGINIA    B    N
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     B    A
FL PNHDL    B    A     FL PENIN    B    A     AK N SLOPE  B    A
AK ALEUTIAN B    B     AK WESTERN  B    N     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    A



8-14 DAY OUTLOOK TABLE
Outlook for Apr 09 - 15 2025

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

$$