150
FXUS06 KWBC 061902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon May 06 2024

6-10 DAY OUTLOOK FOR MAY 12 - 16 2024

Today`s model solutions are in good agreement on the predicted amplified
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, ECENS, and Canadian models due to recent model
skill. The resultant manual blend features a 500-hPa trough and negative
500-hPa height anomalies across the eastern contiguous U.S. (CONUS). A ridge
and associated positive 500-hPa height anomalies are forecast over the
northwestern CONUS, while a weak trough is forecast over the southwestern
CONUS. A trough is forecast over Alaska. Weak troughing with negative 500-hPa
height anomalies are favored for Hawaii.

Mid-level ridging and positive 500-hPa height anomalies across the western
CONUS bring elevated chances for above-normal temperatures over much of the
western CONUS extending eastward through the High Plains, the Upper and Middle
Mississippi Valley, and into the Upper Great Lakes region. The strongest
chances are forecast over parts of Oregon, California, Nevada, and Utah with
probabilities exceeding 70% in this region. Anomalous mid-level troughing
favors near- to below-normal temperatures across much of the Southern Plains
and the eastern CONUS, except for Maine and southern Florida where above-normal
temperatures are indicated. In Alaska, weakly below-normal 500-hPa height
anomalies lead to chances for below-normal temperatures across the state. In
Hawaii, above-normal temperatures are forecast consistent with the
consolidation of tools.

In the Pacific Northwest, below-normal precipitation is likely beneath the
positive 500-hPa height anomalies. The below-normal chances overspread the
northern Rockies and into the Northern Plains. Along the southern and eastern
edge of the trough above-normal precipitation is slightly favored as a surface
frontal boundary is likely to become established that may help to focus
precipitation along the East Coast and Gulf Coast. Areas of surface
low-pressure may develop in the southern Rockies and a weak trough predicted
over the Southwest that may bring precipitation to the region. In Alaska,
above-normal precipitation is forecast over much of Alaska as troughing may
bring onshore flow. In Hawaii, above-normal precipitation is favored due to a
weak trough over the region.

The official 6-10 day 500-hPa height blend consists of 40% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 30% 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 model solutions and forecast temperature and precipitation
tools.


8-14 DAY OUTLOOK FOR MAY 14 - 20 2024

Ensemble mean solutions for the 8-14 day period maintain a fairly persistent
and less amplified 500-hPa circulation pattern relative to the 6-10 day period
across North America and the surrounding regions. During week-2, a ridge is
forecast over the western CONUS. A weak trough with negative anomalies is
forecast over the eastern CONUS. Another weak trough is predicted over Alaska,
while ridging and above-normal 500-hPa heights are forecast over the Aleutians.
A weak trough with slightly below-normal 500-hPa heights continued to be
predicted over Hawaii.

A weak mid-level trough and negative 500-hPa height anomalies supports
near-normal temperature for much of the eastern CONUS, excluding portions of
the Northeast and Florida peninsula where above-normal temperatures are
indicated. Elevated probabilities of above-normal temperatures are forecast
over much of the central and western CONUS due to the forecast ridging and
above-normal 500-hPa heights. In Alaska, below-normal temperatures are slightly
favored with continued weak troughing impacting the state. In Hawaii, slightly
above-normal temperatures are forecast consistent with the consolidation of
tools.

Below-normal precipitation is favored for parts of the Pacific Northwest and
the Northern Rockies with ridging over the region. Near- to above-normal
precipitation is forecast over the remainder of the CONUS due to southerly
return flow associated with mean surface high pressure over the Southeast and
the mid-level trough expected to linger in the region through much of the
period, and supported by most of the dynamical precipitation forecast tools. In
Alaska, above-normal precipitation is generally favored across the state with
unsettled weather beneath a mid-level trough continuing. Meanwhile,
above-normal precipitation is slightly favored for Hawaii consistent with the
consolidation of tools.

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, with
good agreement in the overall circulation pattern for the period, offset by
weaker signals and some disagreement among precipitation and temperature tools.


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
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:
19980514 - 19750430 - 20030420 - 19640501 - 19980519


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:
19980516 - 19980511 - 19750428 - 20030420 - 19640430


6-10 DAY OUTLOOK TABLE
Outlook for May 12 - 16 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for May 14 - 20 2024

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

$$