905
FXUS06 KWBC 171902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Mon June 17 2024

6-10 DAY OUTLOOK FOR JUN 23 - 27 2024

The high amplitude longwave pattern during mid-June is forecast to at least
briefly become more zonal over the contiguous U.S. (CONUS). Despite the
likelihood of a less amplified longwave pattern, the GEFS, ECENS, and CMCE
maintain positive 500-hPa height anomalies during the 6-10 day period with the
largest height departures over California and the Great Basin. Above-normal
temperatures are favored for nearly all of the CONUS except for parts of the
Pacific Northwest due to a trough nearby and enhanced onshore flow.

Due to the predicted transition to a zonal flow pattern with fast-moving
individual shortwave troughs, forecast confidence is limited for the 6-10 day
precipitation outlook. The passage of one to two cold fronts enhance
above-normal precipitation probabilities for the Northeast. Further to the
south across the Mid-Atlantic, Ohio Valley, Middle Mississippi Valley, and
Central Great Plains, these same cold fronts tilt the outlook towards the wet
side, but precipitation amounts are expected to be less than the Northeast. The
GEFS remains bullish on a continued chance of tropical cyclone (TC) development
in the Bay of Campeche or western Gulf of Mexico through late June. This TC
potential along with anomalously moist southeasterly flow favors above-normal
precipitation across the Gulf Coast States, Southern Great Plains, New Mexico,
and eastern Arizona. Enhanced onshore flow favors above-normal precipitation
across western parts of Oregon and Washington, while below-normal precipitation
is more likely for more inland areas of the western CONUS.

Since 500-hPa heights are forecast to be close to average and the 5-day surface
flow is ill-defined, the 6-10 day temperature and precipitation outlooks are
generally based on the consolidation tool, a skill-weighted combination of the
GEFS and ECENS reforecast tools. Above-normal temperatures are favored along
the southern coast and across inland areas, while below-normal temperatures are
more likely along coastal western Alaska and the Aleutians due to below-normal
SSTs. Above-normal precipitation is favored for much of Alaska.

Based on the GEFS and ECENS, near- to below-normal temperatures and
above-normal precipitation are favored for Hawaii.

The official 6-10 day 500-hPa height blend consists of 35% of Today`s 6z GFS
Ensemble Mean centered on Day 8, 40% 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: Forecast confidence: Average, 3
out of 5, due to good agreement among the temperature tools offset by a
transition to a less amplified longwave pattern.

8-14 DAY OUTLOOK FOR JUN 25 - JUL 01, 2024

Following a brief deamplification of the longwave pattern, the GEFS, ECENS, and
CMCE depict that the anomalous 500-hPa ridge is likely to return to the
east-central CONUS by the end of June. These ensemble means feature an
amplifying mid-level ridge (trough) over eastern (western) North America during
the week-2 period. The strengthening ridge with increasing positive 500-hPa
height anomalies support enhanced above-normal temperature probabilities
throughout the eastern and central CONUS. Although an amplifying mid-level
trough is forecast over western North America, any below-normal temperatures
are expected to be limited to the Pacific Northwest and northern Rockies. Due
to decreasing 500-hPa heights compared to yesterday, above-normal temperature
probabilities are lower across California and the Southwest.

The variable longwave pattern during week-2, convective rainfall at this time
of year, and uncertainty on if and where a tropical cyclone emerges from the
Gulf of Mexico result in a low confidence precipitation outlook. Shortwave
troughs, tracking north of the 40th parallel, support slightly elevated
above-normal precipitation probabilities across parts of the north-central
CONUS and northern New England. The wet tilt across the southern tier of the
CONUS is consistent with the consolidation tool, uncalibrated model output, and
the predicted surface pattern. Enhanced onshore flow favors above-normal
precipitation for the Pacific Northwest, while precipitation tools depict
increased below-normal precipitation probabilities from the Great Basin
eastward to the central Rockies and central high Plains.

The manual 500-hPa height blend depicts small negative height anomalies across
much of Alaska. The 8-14 day temperature outlook leans towards the recently
more skillful ECENS reforecast tool but also considered the negative SST
anomalies across the Bering Sea. Due to the proximity of troughing aloft,
above-normal precipitation probabilities are elevated for a majority of Alaska.

Based on the GEFS and ECMWF models, below-normal temperatures and above-normal
precipitation are favored for Hawaii.

The official 8-14 day 500-hPa height blend consists of: 35% of Today`s 6z GFS
Ensemble Mean centered on Day 11, 40% of Today`s 0z European Ensemble Mean
centered on Day 11, and 25% of Today`s 0z Canadian Ensemble Mean centered on
Day 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Forecast confidence: Average, 3
out of 5, due to good agreement among the temperature tools offset by a
variable longwave pattern and uncertainty in the precipitation outlook.

FORECASTER: Brad Pugh

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:
19530627 - 19900604 - 19970626 - 19520617 - 19940613


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:
19530626 - 19970624 - 20060527 - 19530621 - 19520616


6-10 DAY OUTLOOK TABLE
Outlook for Jun 23 - 27 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     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    A     COLORADO    A    A
NEW MEXICO  A    A     N DAKOTA    A    N     S DAKOTA    A    N
NEBRASKA    A    N     KANSAS      A    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A
MINNESOTA   A    N     IOWA        A    N     MISSOURI    A    A
ARKANSAS    A    A     LOUISIANA   A    A     WISCONSIN   A    N
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    A     AK WESTERN  A    N     AK INT BSN  A    A
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    B    A



8-14 DAY OUTLOOK TABLE
Outlook for Jun 25 - Jul 01, 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      N    A     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       N    B     NEVADA      A    B
W MONTANA   N    N     E MONTANA   A    N     WYOMING     A    B
UTAH        A    B     ARIZONA     A    A     COLORADO    A    N
NEW MEXICO  A    A     N DAKOTA    A    A     S DAKOTA    A    N
NEBRASKA    A    N     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    N     MISSISSIPPI A    A     MICHIGAN    A    N
INDIANA     A    N     OHIO        A    N     KENTUCKY    A    A
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    N
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N
MASS        A    N     CONN        A    N     RHODE IS    A    N
PENN        A    N     NEW JERSEY  A    N     W VIRGINIA  A    N
MARYLAND    A    N     DELAWARE    A    N     VIRGINIA    A    N
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  B    N     AK INT BSN  A    A
AK S INT    A    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.

$$