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FXUS06 KWBC 271902
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 27 2024

6-10 DAY OUTLOOK FOR JUN 02 - 06 2024

Today's model solutions are in good agreement on a moderately amplified 500-hPa 
circulation pattern across North America and surrounding regions during the 
6-10 day period. The manual 500-hPa height blend is based primarily on the 
ensemble means from the GEFS, ECMWF, and Canadian models due to recent model 
skill. The resultant manual blend features strong troughing and negative 
500-hPa height anomalies over Alaska and the Gulf of Alaska. Ridging and 
positive height anomalies are forecast over the western and central contiguous 
U.S. (CONUS), while another trough is depicted over the southern East Seaboard 
and western Atlantic. Near- to slightly above-normal 500-hPa heights are 
forecast over the Hawaiian Islands.

Enhanced chances for near- to above-normal temperatures are predicted over much 
of the CONUS (except for portions of Georgia and South Carolina, where 
below-normal temperatures are indicated in association with a trough predicted 
over the southern Eastern Seaboard) due to the anticipated mid-level ridging, 
generally above-normal 500-hPa height anomalies, and increased southwesterly 
surface flow, supported by most of the dynamical temperature forecast tools. 
Probabilities favoring above normal temperatures exceed 80% for parts of the 
Northern and Central Great Basin. Below-normal temperature probabilities are 
increased over Alaska, including the Aleutians and Southeast Alaska, closer to 
the mid-level trough and surface storminess. In Hawaii, slightly above-normal 
temperature probabilities are favored underneath near- to weak positive height 
anomalies.

Anomalous mid-level ridging favors below-normal precipitation over much of the 
western half of the CONUS, except for portions of  the West Coast where 
above-normal precipitation is indicated due to a trough predicted over the Gulf 
of Alaska. In contrast, near- to above-normal precipitation probabilities are 
increased over the remainder of the CONUS due to southerly return flow 
associated with mean surface high pressure over the Southeast and the mid-level 
trough expected to linger in the region through much of the period, and 
supported by most of the dynamical precipitation forecast tools. In Alaska, 
above-normal precipitation chances are elevated over much of Alaska due to the 
trend toward increased troughing to the south and southwest of the state later 
in the period, consistent with most temperature guidance. In Hawaii, 
below-normal precipitation probabilities are slightly elevated across Hawaii 
Islands, consistent with the consolidation precipitation forecast tool. 

The official 6-10 day 500-hPa height blend consists of 40% of Today's 6z GFS 
Ensemble Mean centered on Day 8, 30% of Today's 0z European Ensemble Mean 
centered on Day 8, and 30% 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 
good agreement among model solutions and forecast temperature and precipitation 
tools.

8-14 DAY OUTLOOK FOR JUN 04 - 10 2024 

Ensemble mean solutions for the 8-14 day period predict a fairly consistent 
500-hPa circulation pattern relative to the 6-10 day period across North 
America and the surrounding regions.The GEFS and ECMWF are in good agreement 
regarding a ridge with above-normal 500-hPa heights over the western and 
central CONUS during the week-2 period. Weak anomalous troughing is forecast 
over the eastern CONUS. Stroug troughing and negative 500-hPa height anomalies 
are persistent over Alaska and the Gulf of Alaska. Near- to slightly 
above-normal 500-hPa heights are still predicted over the Hawaiian Islands.

The subtropical ridge and broadly above-normal 500-hPa heights as well as 
increased southwesterly surface flow over the central CONUS favor elevated 
probabilities for near- to  above-normal temperatures for much of the CONUS, 
with the highest probabilities persisting across portions of Northern and 
Central Great Basin. One exception is over parts of the Ohio and Tennessee 
Valley, favoring slightly below-normal temperatures due to lingering influence 
from a trough and negative 500-hPa anomalies predicted over the region. In 
Alaska, below-normal temperature chances are increased over southern portions 
of the State, similar to the 6- to 10-day forecast period given the very 
similar mean mid-level flow pattern. In Hawaii, slightly above-normal 
temperatures are likely over the State, consistent with the consolidation 
temperature forecast tool. 

Increased probabilities for above-normal precipitation are favored across much 
of the southern and eastern CONUS, supported by most of the precipitation 
forecast tools. There is a slight tilt toward elevated below-normal 
precipitation probabilities across the northern Interior West extending 
eastward to the western Upper Great Lakes, under a ridge and positive 500-hPa 
anomalies predicted over the region. There are enhanced chances for 
above-normal precipitation along most of the West Coast, under a moist Pacific 
air mass and some potential influence from the strong troughing centered near 
southern Alaska. This troughing continues to favor enhanced chances for 
above-normal precipitation across most of Alaska. Slightly drier than normal 
weather is likely across the Hawaii islands, consistent with the consolidation 
precipitation forecast tool. 

The official 8-14 day 500-hPa height blend consists of: 30% of Today's 6z GFS 
Ensemble Mean centered on Day 11, 40% 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: 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: Luke H

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: 
19660514 - 19620528 - 19660519 - 20040529 - 19620602


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: 
19660515 - 19620528 - 20040528 - 19660520 - 19620602


6-10 DAY OUTLOOK TABLE
Outlook for Jun 02 - 06 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A     
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    N     
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    B     
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 N    A     MICHIGAN    A    A     
INDIANA     A    A     OHIO        A    A     KENTUCKY    N    A     
TENNESSEE   N    A     ALABAMA     N    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  N    A     W VIRGINIA  N    A     
MARYLAND    N    A     DELAWARE    N    A     VIRGINIA    N    A     
N CAROLINA  N    A     S CAROLINA  N    A     GEORGIA     N    A     
FL PNHDL    N    A     FL PENIN    A    A     AK N SLOPE  B    A     
AK ALEUTIAN B    N     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 Jun 04 - 10 2024

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    A     OREGON      A    A     NRN CALIF   A    A     
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N     
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B     
UTAH        A    N     ARIZONA     A    A     COLORADO    A    N     
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    B     
NEBRASKA    A    B     KANSAS      A    N     OKLAHOMA    A    N     
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A     
MINNESOTA   A    B     IOWA        A    B     MISSOURI    A    N     
ARKANSAS    A    N     LOUISIANA   A    A     WISCONSIN   A    B     
ILLINOIS    A    N     MISSISSIPPI A    A     MICHIGAN    A    N     
INDIANA     N    N     OHIO        N    N     KENTUCKY    N    N     
TENNESSEE   N    N     ALABAMA     N    A     NEW YORK    A    A     
VERMONT     A    A     NEW HAMP    A    A     MAINE       A    A     
MASS        A    A     CONN        N    A     RHODE IS    N    A     
PENN        A    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  N    A     
AK ALEUTIAN B    N     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.

$$