National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS06 KWBC 241902
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 24 2024

6-10 DAY OUTLOOK FOR APR 30 - MAY 04, 2024

Dynamical models agree on the overall 500-hPa circulation pattern forecast over
the region of North America during the 6-10 day period. A trough is forecast to
the west of Mainland Alaska during the period in each of the GEFS, ECMWF and
Canadian ensemble means. Positive 500-hPa height anomalies and a ridge are
forecast over southwest Alaska. A trough predicted off of the Pacific coast of
the contiguous U.S. (CONUS) and a ridge over the central and eastern CONUS are
more amplified in today’s 6-10 day model forecasts than yesterday’s.

Above normal temperatures are favored for the Aleutians, the southern
two-thirds of Mainland Alaska, and Southeast Alaska during the 6-10 day period
under positive 500-hPa height anomalies. Below normal temperatures are favored
for the North Slope, under slightly negative 500-hPa height anomalies. Below
normal temperatures are favored for the northwestern CONUS from central
California northward, under a predicted trough during the period. Above normal
temperatures are likely across most of the remainder of the CONUS, with
probabilities exceeding 70 percent for much of the region, under an amplified
ridge over the central and eastern CONUS. Near normal temperatures are favored
for Hawaii supported by the Auto forecast.

Above normal precipitation is favored for most of Alaska, ahead of a predicted
trough. Below normal precipitation is favored for the Alaska Panhandle,
consistent with most dynamical model forecasts. Near to below normal
precipitation is favored for much of the southwestern CONUS into the central
High Plains, where little or no precipitation is expected during the period for
climatologically relatively dry regions. Above normal precipitation is favored
from the Pacific Northwest across the northern CONUS into the Northern Plains,
ahead of a predicted trough, and for the Southern Plains and upper Mississippi
Valley, with southerly surface moisture transport and as predicted by
calibrated GEFS and ECMWF dynamical model precipitation forecasts. Below normal
precipitation is slightly favored for most of the eastern CONUS, ahead of a
predicted ridge. Below normal precipitation is slightly favored for the Big
Island of Hawaii supported by the Auto forecast.

The official 6-10 day 500-hPa height blend consists of 40% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 40% of Today`s 0z European Ensemble Mean
centered on Day 8, and 20% of Today`s 0z Canadian Ensemble Mean centered on Day
8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: About average, 3 out of 5, with
good agreement among model forecasts for the circulation pattern during the
period, offset by weaker signals and some disagreement among precipitation
tools.

8-14 DAY OUTLOOK FOR MAY 02 - 08 2024

The 500-hPa circulation pattern predicted for the 6-10 day period generally
persists into the 8-14 day period. A trough that is forecast to the west of
Mainland Alaska progresses eastward, lowering mid-level heights over the state.
A predicted trough near the west coast of the CONUS persists into the 8-14 day
period. Positive 500-hPa height anomalies are predicted over the eastern
two-thirds of the CONUS.

Probabilities favororing above normal temperatures for the southern two-thirds
of Mainland Alaska decrease as mid-level heights decrease. Near to below normal
temperatures are favored for the North Slope, supported by calibrated GEFS
model forecasts. Near to below normal temperatures are favored for the West,
under a predicted trough. Above normal temperatures continue to be likely over
the remainder of the CONUS, under predicted positive 500-hPa height anomalies.
Below normal temperatures are slightly favored for the northwestern island of
Hawaii, with increasing cloudiness in the model forecasts.

A predicted trough to the west of Alaska increases chances of above normal
precipitation across most of the state, excluding the Alaska Panhandle. Above
normal precipitation is favored for much of the West across the Northern
Rockies into the Northern Plains and western Great Lakes region, ahead of the
predicted trough. Above normal precipitation is slightly favored for the Great
Plains and upper Mississippi Valley, as moisture streams northward into the
region early in the period. Below normal precipitation is favored for much of
the eastern CONUS, ahead of a predicted ridge. Above normal precipitation is
slightly favored for northwestern islands of Hawaii supported by the Auto
forecast.

The official 8-14 day 500-hPa height blend consists of: 40% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 40% of Today`s 0z European Ensemble Mean
centered on Day 11, and 20% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Slightly below average, 2 out of
5, with general agreement among dynamical models for the overall circulation
pattern during the period, offset by weaker signals in the precipitation tools,
and some disagreement among both precipitation and temperature tools.

FORECASTER: D Collins

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
16.


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:
19900507 - 19900416 - 19940404 - 19770406 - 20000409


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:
19510403 - 19520403 - 19530403 - 19540403 - 19550403


6-10 DAY OUTLOOK TABLE
Outlook for Apr 30 - May 04, 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for May 02 - 08 2024

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

$$