561
FXUS06 KWBC 141902
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 14 2024

6-10 DAY OUTLOOK FOR MAY 20 - 24 2024

Todays model solutions have come into better agreement over the last few days
and the GEFS, ECMWF, and CMCE all depict a similar synoptic picture over the
6-10 day forecast period, although differences still remain when considering
the daily evolution of various features. Todays manual blend features
widespread positive height anomalies over the North Pacific, a weak subtropical
ridge centered over southeastern Texas, and troughing over the northwestern and
north-central CONUS. Weak troughing is also favored near the East Coast.

Subtropical ridging favors above-normal temperatures for much of the southern
and eastern contiguous U.S. (CONUS), with probabilities exceeding 80% for
portions of South Texas. Troughing over the West Coast favors below-normal
temperatures for much of the CONUS west of the Rockies, especially the
northwest CONUS where probabilities exceed 50%. Portions of southern California
also have enhanced chances of below-normal temperatures, consistent with most
forecast tools. For Alaska, increased northwesterly flow aloft favors increased
cloudiness and below-normal temperatures for the Alaskan Interior and extending
southeastward through the Panhandle, while the North Slope tilts slightly
towards above-normal temperatures, as indicated by the GEFS and ECMWF
reforecast tools. The Hawaii ERF consolidation (CON) favors above-normal
temperatures for the entire state.

Troughing over both coasts and positive height anomalies centered over northern
Mexico develop a stronger than normal jet stream for this time of year,
favoring a more active pattern which tilts the odds toward above-normal
precipitation for most of the CONUS east of the Rockies. The subtropical ridge
favors below-normal precipitation for portions of the southern CONUS,
especially for portions of southern New Mexico and southeastern Texas. Much of
Alaska tilts towards above-normal precipitation with weak troughing favored
over eastern Siberia although model solutions generally keep the enhanced
potential for precipitation confined to the Mainland and below-normal
precipitation is slightly favored for the southern coast and the Panhandle of
Alaska. The Hawaii CON indicates above-normal precipitation for most of the
state, with odds increasing from east to west, while near-normal precipitation
is most likely for the Big Island.

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: Above average, 4 out of 5, with
good run-to-run continuity among forecast models, offset by differences between
models regarding strength and position of various synoptic features.

8-14 DAY OUTLOOK FOR MAY 22 - 28 2024

Ensemble mean solutions for the 8-14 day (week-2) period predict a
de-amplification of the 500-hPa circulation pattern relative to the 6-10 day
period across North America and the surrounding regions. Height anomalies are
weaker relative to the 6-10 day period as the synoptic pattern becomes more
zonal and spread among model solutions increases. During week-2, positive
500-hPa height anomalies persist over the North Pacific and the south-central
and southeastern CONUS, while weak troughing continues over the coasts. This
persistence of the synoptic pattern results in similar outlooks between
forecast periods for both temperature and precipitation.

Above-normal temperatures continue to be favored for the southern CONUS east of
the Rockies. Continued troughing over both coasts favors an eastward expansion
of chances for below-normal temperatures as far as the Great Lakes, while
near-normal temperatures become most likely for the northeastern CONUS. Western
Alaska continues to tilt towards below-normal temperatures with northwesterly
flow aloft continuing, while reforecast tools continue to favor a slight tilt
towards above-normal temperatures for the North Slope, and indicate a similar
tilt for southeastern Alaska as well. Most of Hawaii continues to be favored
for above-normal temperatures, although near-normal temperatures are now most
likely for the Big Island, consistent with todays autoblend and Hawaii CON
tool.

Subtropical ridging over the southern CONUS continues to favor below-normal
precipitation for portions of the Four Corners, southeastern Texas, and south
Florida, while the weak troughing present on both coasts results in a tilt
towards above-normal precipitation for much of the CONUS, supported by the
majority of forecast tools. Continued troughing over Siberia favors
above-normal precipitation for much of the Alaskan Mainland, however surface
flow is favored to become southeasterly over the Panhandle, resulting in a
slight tilt towards below-normal precipitation. Above-normal precipitation
continues to be favored for Hawaii, especially Kawai.

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, with
good run-to-run continuity among forecast models, offset by differences between
models regarding strength and position of various synoptic features.

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 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:
19710506 - 19730518 - 19520523 - 20060504 - 20060427


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:
19990527 - 19710505 - 19730519 - 19520521 - 20060504


6-10 DAY OUTLOOK TABLE
Outlook for May 20 - 24 2024

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



8-14 DAY OUTLOOK TABLE
Outlook for May 22 - 28 2024

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

$$