047
FXUS06 KWBC 141933
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Fri June 14 2024

6-10 DAY OUTLOOK FOR JUN 20 - 24 2024

Dynamical models remain in very good agreement regarding the 500-hPa height
pattern across North America during the 6-10 day period. At the outset of the
period, highly amplified ridging is forecast across the eastern CONUS, with the
0z ECENS, GEFS, and CMCE indicating 500-hPa heights near or greater than 594
dam over parts of the Ohio Valley, Mid-Atlantic, and Northeast. Troughing is
initially favored across the West, with the mid-level pattern forecast to
de-amplify across the CONUS by day-10, resulting in weakening positive height
anomalies in the East and increasing positive height anomalies in the West.
Todays manual 6-10 day height blend depicts positive 500-hPa height anomalies
east of the Rockies, with a maxima exceeding +100 meters over New England.
Slightly above-normal heights in the mean are forecast across the West given
the transitional pattern, and across Alaska, a weak mid-level trough is
expected to drift from the Bering Sea into the Gulf of Alaska, leaving slightly
above-normal heights over or near the western Mainland and near- to
below-normal heights along the southern tier of the state and the adjacent
North Pacific Ocean.

Strong ridging and its associated positive height anomalies favor high
probabilities of above-normal temperatures throughout much of the eastern and
central CONUS. The largest probabilities (above 80 percent) are forecast across
the eastern Great Lakes and most of the Northeast where the ECENS depicts 5-day
temperatures averaging more than 10 degrees F above normal. Farther west, the
amplified mid-level trough will keep temperatures near or below normal for the
first day or two, but rebounding heights will engender rising temperatures
later in the period, and so above-normal temperatures are favored over the
western half of the CONUS as well for the period as a whole. The only part of
the CONUS without enhanced chances for above-normal temperatures is southern
and western Texas due to the likelihood of persistent, above-normal rainfall.
Over Alaska, a weakening mid-level trough drifting southeastward brings
slightly enhanced chances for subnormal temperatures to western and northern
Alaska including the Aleutians, with marginally-elevated near- to above-normal
temperature chances over the remainder of the state. Enhanced above-normal
temperature probabilities are favored across Hawaii, consistent with the
consolidation forecast tool and expected above-normal sea surface temperatures.

A tropical or semi-tropical storm system feature is forecast to be near
southern Texas as the 6- to 10-day period gets underway, resulting in heavy
rainfall across that region according to the ECENS, CMCE, and GEFS. Thereafter,
the evolution of this system is uncertain, with the CMCE pushing heavy rain
across Florida and the immediate Gulf Coast region, the ECENS surging moisture
farther northward across the central Gulf Coast region and adjacent Southeast,
and the GEFS keeping the heaviest rains over the Gulf of Mexico. All of these
ensemble means, however, show the potential for at least moderate rains to
linger around southern Texas for much of the period. The 6-10 day precipitation
outlook reflects a compromise of these solutions, with above-normal
precipitation probabilities exceeding 50 percent from south Texas northeastward
along western and central portions of the immediate Gulf Coast, and topping 40
percent farther east and north across the rest of the Gulf Coast and adjacent
Southeast as well as the Florida Peninsula. Farther west, most guidance shows a
surge of semi-tropical moisture and some rainfall pushing into parts of the
central and eastern Four Corners region, reflected by a better than 50 percent
chance for surplus rainfall from easternmost Arizona through the western half
of New Mexico and some adjacent areas. Odds for heavier rains drop off farther
west, where the moisture flow will be less robust and in situ dry air may
reduce amounts. Troughing aloft early in the period favors above-normal
precipitation across the Rockies and High Plains while southerly, anomalously
moist flow may interact with a wavering frontal boundary, increasing odds for
heavy rainfall across the northern tier of the CONUS from the Great Plains
through New England. South of this area, raw and reforecast precipitation
guidance from the ECENS and GEFS lean toward subnormal precipitation from the
Middle Mississippi Valley through much of the Ohio Valley and into the
mid-Atlantic region and South Atlantic States. In contrast, the CMCE favors
near- normal or slightly above-normal rainfall across this area. The official
outlook favors neither unusually wet nor unusually dry weather due to the
inconsistent guidance, except in parts of the Carolinas where the ECENS and
GEFS are drier than in other locations. Meanwhile, the rebounding 500-hPa
heights over the western CONUS bring enhanced odds for deficient precipitation
to parts of northern California, much of Nevada, and some adjacent locales.
With weak troughing moving from west of Mainland Alaska into the Gulf of
Alaska, elevated above-normal precipitation chances cover most of the state,
especially southeastern areas, and above-normal precipitation probabilities are
increased across Hawaii.

The official 6-10 day 500-hPa height blend consists of 45% of Today`s GFS
Superensemble Mean centered on Day 8, 35% 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, due to
high confidence regarding high temperatures over much of the country,
especially in the East early in the period, offset by some increasing
uncertainty in the evolution of mid-level features and the resulting
precipitation pattern toward day-10.

8-14 DAY OUTLOOK FOR JUN 22 - 28 2024

Although the models are in good agreement on the mean 500-hPa pattern during
week-2, there is some increasing uncertainty due to decreasing amplification of
the mid-level pattern across the CONUS. Typically, this results in weaker
surface and mid-level features driving the sensible weather across the
continent, and such features are always more difficult for the models to
forecast accurately, especially later in the period. The pattern evolution
during week-2 is expected to feature continued de-amplification of the ridge in
the East, marginal troughing lingering near or west of British Columbia, and
some expansion of positive height anomalies through much of the western CONUS.
The manual height blend for week-2 depicts weakly positive height anomalies
across much of the CONUS in the mean, with a maxima between +30 and +60 meters
from the Southwest through the middle of the CONUS and across the Northeast. A
small region of nominally below-normal heights is anticipated over or near
southwestern Canada while slightly positive 500-hPa height anomalies are
forecast over Alaska as troughing over the Gulf of Alaska at the outset of the
period drifts southeastward.

Due to the broad coverage of positive 500-hPa height anomalies, elevated
probabilities for above-normal temperatures cover most of the CONUS. The
highest probabilities (above 70 percent) are highlighted across the lower
Northeast and much of the mid-Atlantic region, which will be on the southern
fringe of the larger positive 500-hPa height anomalies with abnormally high
temperatures already in place. Across the CONUS, subnormal temperatures are
only favored across northwestern Washington, closest to the weak mid-level
troughing in southwestern Canada. In Hawaii, above-normal temperatures continue
to be favored, consistent with the consolidation tool and anticipated
above-normal sea surface temperatures.

As in the 6-10 day forecast, there is good agreement regarding increased
tropical moisture across the Gulf Coast, particularly from eastern and southern
Texas through the central Gulf Coast region and adjacent Lower Mississippi
Valley and Southeast. The ECMWF reforecast tool is particularly robust with
rainfall totals in this region, but the other ensembles also show above-normal
amounts here. These factors support probabilities for surplus rainfall
exceeding 50 percent across these areas, with odds of better than 40 percent
reaching into central and northeastern Texas, to near the Ohio/Mississippi
Rivers confluence, and the western Florida Peninsula. Also similar to the 6-
to 10-day period, raw and re-forecast ensemble means show some level of
enhanced moisture advection into the Four Corners region, with the ECENS
reforecast tool being the most robust. This supports enhanced chances for
above-normal precipitation exceeding 50 percent from easternmost Arizona into
central New Mexico. In situ dry air and somewhat less moisture advection will
likely inhibit precipitation totals farther west. Over the rest of the CONUS,
raw and reforecast precipitation guidance generally favors slightly elevated
odds for above-normal precipitation, and a nominal tilt of the odds in this
direction is depicted in the official forecast. Across Alaska, the lower
mid-level heights and onshore surface flow favor below-normal temperatures and
above-normal precipitation in Southeastern Alaska while a slight tilt of the
odds toward warmer and wetter than typical conditions exists for most of the
Mainland. The consolidation tool shows increased chances for above-normal
precipitation  throughout Hawaii, and this is reflected in the official outlook.

The official 8-14 day 500-hPa height blend consists of: 33% of Today`s GFS
Superensemble 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: Average, 3 out of 5, due to good
agreement regarding the pattern evolution, offset by more uncertainty inherent
to a less amplified pattern, particularly in regards to the precipitation
forecast.

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
June 20.


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:
20070619 - 20010619 - 20030530 - 19940611 - 19590621


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:
20010619 - 20070618 - 19960604 - 19770603 - 19870604


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

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    N     OREGON      A    B     NRN CALIF   A    B
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    B
W MONTANA   A    N     E MONTANA   N    A     WYOMING     A    A
UTAH        A    N     ARIZONA     A    A     COLORADO    A    A
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     N    A     W TEXAS     A    A
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    N
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   A    A
ILLINOIS    A    A     MISSISSIPPI A    N     MICHIGAN    A    A
INDIANA     A    N     OHIO        A    N     KENTUCKY    A    N
TENNESSEE   A    N     ALABAMA     A    N     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    N     NEW JERSEY  A    N     W VIRGINIA  A    N
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
N CAROLINA  A    B     S CAROLINA  A    N     GEORGIA     A    N
FL PNHDL    A    A     FL PENIN    A    A     AK N SLOPE  N    N
AK ALEUTIAN B    N     AK WESTERN  N    N     AK INT BSN  N    A
AK S INT    N    A     AK SO COAST N    A     AK PNHDL    N    A



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

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  N    A     OREGON      A    N     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    B
W MONTANA   A    N     E MONTANA   A    A     WYOMING     A    A
UTAH        A    N     ARIZONA     A    A     COLORADO    A    A
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    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   A    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    N
AK ALEUTIAN B    N     AK WESTERN  N    N     AK INT BSN  N    N
AK S INT    N    A     AK SO COAST N    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.

$$