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Prognostic Meteorological Discussion (PMD)

Issued by National Weather Service (NWS)

                            
000
FXUS06 KWBC 181902
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue June 18 2019

6-10 DAY OUTLOOK FOR JUN 24 - 28 2019

Today's GFS, ECMWF and Canadian ensemble means are in good agreement on the 
500-hPa pattern throughout the forecast domain in the 6-10 day period. A ridge 
is predicted in the Northern Pacific near Alaska. Downstream troughing is 
forecast over the western CONUS and ridging is predicted to amplify over the 
central-eastern CONUS. The resultant manual blend features positive 500-hPA 
height anomalies for Alaska, negative 500-hPa height anomalies over the West 
and northern-central tier of the CONUS, and positive 500-hPa height anomalies 
over the Northeast. 

Below normal temperatures are favored for the western CONUS, and parts of the 
Northern and Central Plains as a result of troughing forecast over the region. 
Chances of above normal temperatures are enhanced over the Southern Plains and 
much of the eastern CONUS, influenced by low-level southerly flow. Above normal 
temperatures are favored over parts of the Upper Mississippi Valley, consistent 
with the dynamical forecast tools. Above normal temperatures are most likely 
for Alaska, due to the forecast positive 500-hPa height anomalies. 

Anomalous troughing upstream over the West and multiple shortwave troughs lead 
to enhanced probabilities of above normal precipitation over much of the 
northwestern CONUS, and eastward to much of the east-central CONUS. Increased 
below normal precipitation probabilities are forecast over parts of the 
Southwest, the Gulf Coastal region and the Florida Peninsula, consistent with 
the forecast consolidation tool. Below normal precipitation probabilities are 
increased over Alaska, underneath predicted 500-hPa ridging over the region. 
Above normal precipitation is likely for parts of the western Aleutians, ahead 
of a forecast trough.

The official 6-10 day 500-hPa height blend consists of 10% of Today's 0z GFS 
Ensemble Mean centered on Day 8, 10% of Today's 6z GFS Ensemble Mean centered 
on Day 8, 10% of Today's GFS Superensemble Mean centered on Day 8, 10% of 
Today's operational 6z GFS centered on Day 8, 30% of Today's 0z European 
Ensemble Mean centered on Day 8, 10% of Today's operational 0z ECMWF 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 
good agreement between models on the predicted 500-hPa height pattern.

8-14 DAY OUTLOOK FOR JUN 26 - JUL 02, 2019 

Models are in fair agreement on the 500-hPa height pattern in week-2. The 0Z 
ECMWF ensemble mean is the most amplified with the trough over the west. 
Anomalous troughs are forecast west of the Aleutians and over the western 
CONUS. The amplified ridges are forecast to extend from the north Pacific to 
Alaska, and over the central part of the CONUS. The resultant manual blend 
indicates negative 500-hPa height anomalies for the western CONUS. Above normal 
heights are forecast for Alaska and the central-eastern CONUS.     

Probabilities of above normal temperatures are increased for Alaska, due to 
forecast above normal 500-hPa heights over the region. Chances of above normal 
temperatures are also enhanced over the central and the eastern CONUS 
associated with the positive 500-hPa height anomalies. Near to below normal 
temperatures are favored for much of the Western CONUS as a result of forecast 
troughing. 

Above normal precipitation chances are elevated for the northwestern CONUS, 
parts of the northern Plains, the Upper and Middle Mississippi Valley, the 
Great Lakes region, the Ohio and Tennessee Valleys, and the Mid-Atlantic, 
consistent with the consolidation forecast tool. Below normal precipitation is 
favored for parts of the Southwest and the Central and Southern Plains, the 
Florida Peninsula and the Northeast, consistent with the dynamical forecast 
tools. Increased chances of below normal precipitation are forecast for much of 
Alaska, due to forecast ridging over the region. Above normal precipitation 
probabilities are increased over southwestern mainland Alaska and the 
Aleutians, ahead of a forecast trough. 

The official 8-14 day 500-hPa height blend consists of: 10% of Today's 0z GFS 
Ensemble Mean centered on Day 11, 10% of Today's 6z GFS Ensemble Mean centered 
on Day 11, 10% of Today's GFS Superensemble Mean centered on Day 11, 10% of 
Today's operational 6z GFS centered on Day 11, 40% of Today's 0z European 
Ensemble Mean centered on Day 11, and 20% 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 fair 
agreement between models on the predicted 500-hPa height pattern initially, 
offset by uncertainty related to the amplitude of upper-level troughing over 
the West.

FORECASTER: Y. Fan

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 1981-2010 base period means for 
temperature...precipitation...and 500-hpa heights 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: 
19600702 - 19870626 - 19820614 - 19770618 - 19680622


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: 
19600701 - 19870626 - 19820614 - 19750530 - 19560627


6-10 DAY OUTLOOK TABLE
Outlook for Jun 24 - 28 2019

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  B    A     OREGON      B    A     NRN CALIF   B    A     
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    B     COLORADO    B    B     
NEW MEXICO  B    B     N DAKOTA    N    A     S DAKOTA    N    A     
NEBRASKA    B    A     KANSAS      B    A     OKLAHOMA    N    A     
N TEXAS     A    A     S TEXAS     A    A     W TEXAS     A    A     
MINNESOTA   A    A     IOWA        N    A     MISSOURI    N    A     
ARKANSAS    A    A     LOUISIANA   A    B     WISCONSIN   N    A     
ILLINOIS    N    A     MISSISSIPPI A    A     MICHIGAN    N    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    N     
MASS        A    A     CONN        A    A     RHODE IS    A    N     
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    N     FL PENIN    A    B     AK N SLOPE  A    B     
AK ALEUTIAN A    A     AK WESTERN  A    B     AK INT BSN  A    B     
AK S INT    A    B     AK SO COAST A    B     AK PNHDL    A    B     
 
                           

8-14 DAY OUTLOOK TABLE
Outlook for Jun 26 - Jul 02, 2019

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

$$