815
FXUS06 KWBC 011934
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon July 01 2024

6-10 DAY OUTLOOK FOR JUL 07 - 11 2024

Models are in very good agreement with the 500-hPa mean heights, and also the
daily evolution of individual features. The ensemble means, deterministic GFS,
and deterministic European Model (ECMWF) all show a strong mean mid-level ridge
in western North America, with an axis aligned near the Pacific Coast and the
largest 500-hPa height anomalies (near +90 dm) over the Pacific Northwest.
Downstream, a relatively weak mid-level trough stretches from northern Canada
southward through the Plains, Mississippi Valley, and parts of the Ohio Valley.
The trough leads into another mid-level ridge downstream over the eastern
contiguous U.S. (CONUS) and the western North Atlantic, with the highest
500-hPa heights near Atlantic Canada. Meanwhile, subnormal mean 500-hPa heights
cover most of Alaska. There is a little uncertainty regarding both the mean
mid-level trough in central North America and the downstream ridge farther
east. The GEFS shows a weaker mean mid-level trough over the central CONUS than
the other two, which show a 500-hPa anomaly center over the Great Lakes as
opposed to a north-south band of slightly below-normal 500-hPa heights in the
GEFS. The stronger solutions of the Canadian and European ensemble means are
favored since this is indicated by most of the tools. To the east, the
mid-level ridge across eastern North America  is weaker and farther east in the
Canadian ensemble mean than in other guidance, and again the stronger solution
depicted by a majority of the tools is favored. This leaves a fairly amplified
pattern across the CONUS. Elsewhere, subnormal mean 500-hPa heights are
expected across most of Alaska, and slightly above normal mean heights are
anticipated across Hawaii.

The models are also very similar in the details of how the pattern evolves.
Mid-level features move little and are generally less amplified at the end of
the period. Heights climb closer to normal over Alaska, and remain slightly
above normal across Hawaii. Meanwhile, the mid-level trough near the central
CONUS retracts northward with time, leading to above-normal 500-hPa heights
covering across most of the CONUS, with a ridge axis centered near the interior
western CONUS, and another in the western North Atlantic. Some model solutions
show a slower evolution toward broadly above-normal 500-hPa heights in the
CONUS, but the favored models with more amplified mid-level features depict a
quicker transition, so the outlooks lean in this direction.

This pattern strongly favors enhanced chances for above-normal temperatures
through most of the CONUS, and near normal temperatures over part of the
central CONUS under the mean mid-level trough. Excessive heat is possible for
much of the period across parts of the interior West through the California
Valleys, where odds for above-normal temperature exceed 80 percent. Enhanced
chances for above-normal temperatures are also forecast in much of the eastern
CONUS, with odds exceeding 60 percent from the Appalachians to the Atlantic
Coast. Subnormal 500-hPa heights should favor below-normal temperatures across
Alaska which increase in western parts of the state. But near-normal
temperatures are expected over Hawaii despite above-normal mean 500-hPa
heights, as models depict a small area of subnormal 850-hPa temperature
lingering over the Islands, which would keep temperatures relatively low.

The highest chances for wetter than normal weather cover southern Texas.
Tropical moisture, including some from the remnants of Hurricane Beryl, is
expected to flow northward into this area due to a weakness in the subtropical
ridge. Deep South Texas has odds exceeding 60 percent for wetter than normal
weather. Conditions are less extreme elsewhere, with the western CONUS ridge
expected to bring drier than normal weather to most of the western CONUS and
the northern half of the Plains, especially near the greatest 500-hPa anomalies
across the Pacific Northwest. Over the rest of the CONUS, cyclonic mid-level
flow downstream from the mean trough slightly increases the odds for wetter
than normal weather. The below-normal 500-hPa heights over Alaska increase
chances for above-normal precipitation there somewhat, and a slight tilt of the
odds favoring wetter than normal weather is also forecast across Hawaii.

The official 6-10 day 500-hPa height blend consists of 15% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 20% of Today`s GFS Superensemble Mean centered
on Day 8, 25% of Today`s 0z European Ensemble Mean centered on Day 8, 15% of
Today`s operational 0z ECMWF centered on Day 8, and 25% 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 and model-to-model consistency offset by slight
differences in the evolution of the mid-level pattern, and uncertainties
regarding the tropical moisture expected to push into southern Texas.

8-14 DAY OUTLOOK FOR JUL 09 - 15 2024

The progression toward increasing mid-level 500-hPa across the CONUS continues
during week-2, which is an evolution generally favored by all ensemble means.
During this period, the mid-level ridge in the western CONUS remains moderately
amplified and meanders a little, although model differences increase
uncertainty in the evolution of the mid-level pattern. The different ensemble
means end week-2 with the ridge axis somewhere from the interior western CONUS
to near the Great Plains. Given good model agreement, a mid-level ridge is
expected to be centered somewhere over the western half of the CONUS, but there
is no reason to favor the specific placement of the ridge axis in any one model
relative to the others. Again, the Canadian ensemble mean shows the pattern
evolving more slowly, with less of a rebound in 500-hPa heights across the
eastern CONUS, but the faster solutions of the other models seem most likely at
this time. Farther north, mid-level heights are expected to slowly increase
across Alaska during the period while remaining slightly below normal, with
little movement in mid-level features there. Slightly elevated 500-hPa heights
are expected over Hawaii.

The broadly above-normal 500-hPa heights favor warmer than normal weather
throughout the CONUS, with excessive heat remaining possible at times from the
California Valleys to the Rockies. Odds for above-normal temperature exceed 70
percent across that region. A secondary maximum in the chances for above-normal
temperatures covers the Northeast and parts of Florida, where 500-hPa heights
should be above-normal longer than in areas farther west. Warmer than normal
weather exceeds 60 percent there. Only parts of Deep South Texas, in an area of
enhanced precipitation due to the influx of tropical moisture, has no increase
in the likelihood of above-normal temperatures. Persisting below-normal
mid-level heights across Alaska keeps elevated odds for colder than normal
weather across the state, and the expected above-normal 500-hPa heights coupled
with slightly below normal 850-hPa temperatures should keep temperature
unremarkable across Hawaii.

The tropical moisture influx into southern Texas should persist through at
least part of week-2, maintaining significantly elevated chances (over 50
percent) for wetter than normal weather. To the south of the positive 500-hPa
height anomaly in the west, some tools indicate a surge of monsoon-related
moisture in the Southwest, where chances for wet weather also exceed 50 percent
in some areas. There is more uncertainty elsewhere. The drifting mid-level
ridge generally favors suppressed precipitation from the northern Plains to the
Pacific Northwest while cyclonic flow across the eastern CONUS (despite
increasing 500-hPa heights) marginally favors above-normal precipitation there.
Slightly enhanced chances for wetter than normal weather also encompass both
Alaska and Hawaii, consistent with tools derived from the ensemble means.

The official 8-14 day 500-hPa height blend consists of: 15% of Yesterday`s 6z
GFS Ensemble Mean centered on Day 10, 20% of Yesterday`s GFS Superensemble Mean
centered on Day 10, 15% of Yesterday`s operational 0z GFS centered on Day 10,
35% of Yesterday`s 0z European Ensemble Mean centered on Day 10, and 15% of
Yesterday`s 0z Canadian Ensemble Mean centered on Day 10


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
regarding the strength and position of some synoptic features, plus
uncertainties inherent in the anticipated influx of moisture into southern
Texas and the Desert Southwest.

FORECASTER: Rich Tinker

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
July 18.


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:
19650630 - 19940715 - 19920615 - 19880614 - 19580710


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:
19510610 - 19520610 - 19530610 - 19540610 - 19550610


6-10 DAY OUTLOOK TABLE
Outlook for Jul 07 - 11 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    B
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B
UTAH        A    B     ARIZONA     A    N     COLORADO    A    B
NEW MEXICO  A    N     N DAKOTA    N    B     S DAKOTA    N    B
NEBRASKA    N    B     KANSAS      N    N     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   N    N     IOWA        N    N     MISSOURI    N    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   N    N
ILLINOIS    N    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    N     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



8-14 DAY OUTLOOK TABLE
Outlook for Jul 09 - 15 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    N
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    N
NEBRASKA    A    N     KANSAS      A    N     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     N    A     W TEXAS     A    A
MINNESOTA   A    B     IOWA        A    N     MISSOURI    A    N
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   A    N
ILLINOIS    A    N     MISSISSIPPI A    A     MICHIGAN    A    N
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  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.

$$