Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
672
FXUS06 KWBC 131922
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 13 2024
6-10 DAY OUTLOOK FOR MAY 19 - 23 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 significant differences still remain when
considering the daily evolution of various features. The above ensembles were
weighted equally and the resultant manual blend features widespread positive
height anomalies over the North Pacific, a weak subtropical ridge centered over
northern Mexico, and weak troughing over both the West and East Coasts.
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 portions of the northwest CONUS, especially Washington where
probabilities exceed 50%. Portions of southern California also tilt slightly
toward below-normal temperatures, consistent with most forecast tools. For
Alaska, increased northwesterly flow aloft favors increased cloudiness and
below-normal temperatures for much of the state, except for the North Slope
which tilts slightly towards above-normal temperatures, as indicated by the
GEFS and ECMWF reforecast tools. The Hawaii ERF consolidation favors
above-normal temperatures for the entire state.
Weak 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 much of the CONUS. The subtropical ridge favors below-normal
precipitation for portions of the southern CONUS, especially for portions of
southern New Mexico. 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 so near-normal precipitation is favored for the Panhandle of Alaska.
The Hawaii CON indicates above-normal precipitation for the whole state, with
odds increasing from east to west.
The official 6-10 day 500-hPa height blend consists of 33% of Today`s 0z GFS
Ensemble Mean centered on Day 8, 34% 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: About average, 3 out of 5, with
moderate agreement among forecast models and tools regarding the overall
synoptic picture, offset by differences between models regarding strength and
position of various features.
8-14 DAY OUTLOOK FOR MAY 21 - 27 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 northern Mexico,
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 chance for below-normal temperatures as far as the Great Lakes, while
near-normal temperatures become most likely for the northeastern CONUS. For
Alaska much of the state 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.
Subtropical ridging over northern Mexico continues to favor below-normal
precipitation for portions of New Mexico and West Texas, 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 the western islands.
The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 0z GFS
Ensemble Mean centered on Day 11, 35% 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
moderate agreement among forecast models and tools regarding the overall
synoptic picture, offset by differences between models regarding strength and
position of various features and weaker height anomalies.
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:
19730518 - 19710505 - 20060504 - 19520520 - 19610519
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:
19730519 - 19520520 - 19710525 - 19710505 - 19610519
6-10 DAY OUTLOOK TABLE
Outlook for May 19 - 23 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B N NRN CALIF N A
SRN CALIF B A IDAHO B A NEVADA N A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH N A ARIZONA N B COLORADO A A
NEW MEXICO A B N DAKOTA B A S DAKOTA N 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 N A MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN N A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B N AK PNHDL B N
8-14 DAY OUTLOOK TABLE
Outlook for May 21 - 27 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B N NRN CALIF B N
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B A ARIZONA B N COLORADO B A
NEW MEXICO A B N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS N A OKLAHOMA A A
N TEXAS A N 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 B A
INDIANA N A OHIO N A KENTUCKY N A
TENNESSEE A A ALABAMA A A NEW YORK N A
VERMONT N A NEW HAMP N A MAINE N 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 A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A N AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN N A
AK S INT B A AK SO COAST B N AK PNHDL B 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.
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