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Prognostic Meteorological Discussion (PMD)

Issued by National Weather Service (NWS)

                            
000
FXUS06 KWBC 241947
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 24 2019

6-10 DAY OUTLOOK FOR JUN 30 - JUL 04, 2019

Model solutions are in good agreement on the predicted circulation pattern over 
North America during the 6-10 day period. Recent ECMWF, GEFS and Canadian 
ensemble means each predict ridging over the western Aleutians and troughing 
over the Bering Sea and parts of western Alaska. All model solutions predict an 
amplified trough downstream over the North Pacific off of the Pacific coast of 
North America, ridging over the northern central CONUS, and a trough over the 
Northeast CONUS and southward off of the Atlantic Coast. The predicted trough 
over the North Pacific is more amplified in the GEFS ensemble mean, while the 
ridge over the northern central CONUS is more amplified in the ECMWF. The 
official manual 500-hPa blend weights the ECMWF model the highest, due to 
recent greater anomaly correlation skill scores. The manual 500-hPa blend 
indicates positive 500-hPa height anomalies over the Aleutians and across the 
Gulf of Alaska into the Alaska Panhandle and negative 500-hPa height anomalies 
over the Bering Sea and northern Alaska. The manual blend indicates weak 
positive 500-hPa height anomalies over much of the CONUS with the exceptions of 
parts of the California coast and New England. Stronger positive 500-hPa height 
anomalies are indicated over the northern Central CONUS. 

Above normal temperatures are likely over most of the CONUS under predicted 
weak positive 500-hPa height anomalies. Probabilities of above normal 
temperatures are greatest  for the northern central CONUS with a predicted 
ridge over the region. Near normal temperatures are more likely for the 
Northeast under a predicted trough. Near to below normal temperatures are 
favored over parts of northern and central California into Nevada, ahead of a 
predicted trough over the North Pacific, and over parts of eastern Texas and 
the Southern Plains, due to the moderation of temperatures by an above normal 
precipitation forecast. Above normal temperatures are probable for the 
Aleutians and Alaska Panhandle, under predicted positive 500-hPa height 
anomalies, and along the west coast of Alaska due to above normal sea surface 
temperatures near the region. Below normal temperatures are more likely for 
parts of the central Alaska mainland, under negative 500-hPa height anomalies. 

Probabilities of above normal precipitation are enhanced for the Aleutians, 
along an expected storm track, and for most of the Alaska mainland ahead of a 
predicted trough over the Bering Sea, while below normal precipitation is more 
likely for the Alaska Panhandle. Near or below normal precipitation is expected 
for much of the western CONUS, much of which is climatologically dry and 
indicated as near normal. Above normal precipitation is more likely from 
eastern Texas northeastward into the Central Mississippi Valley and the 
Tennessee and Ohio Valleys, as moisture is predicted to be drawn northward from 
the Gulf of Mexico by low-level southerly flow. Above normal precipitation is 
also predicted to be likely east of the Rockies from eastern Montana, Wyoming 
and Colorado into the Northern Plains and Great Lakes region, with a potential 
for storm systems to develop and propagate over the expected ridge. Near to 
below normal precipitation is likely for much of the Eastern Seaboard, ahead of 
the predicted ridge, with a small area of likely above normal precipitation 
indicated for Maine, under a predicted trough. 

The official 6-10 day 500-hPa height blend consists of 25% of Today's 6z GFS 
Ensemble Mean centered on Day 8, 45% 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 the model 500-hPa circulation forecasts and among the 
temperature and precipitation forecast tools.

8-14 DAY OUTLOOK FOR JUL 02 - 08 2019 

Ensemble means from the ECMWF, GEFS and Canadian model forecasts are in fair 
agreement on the predicted week 2 500-hPa circulation pattern, with some 
differences in the evolution of the pattern among models. The ECMWF ensemble 
mean indicates slightly positive 500-hPa height anomalies over much of the 
CONUS in week 2, in comparison to the recent GEFS ensemble means that indicate 
slightly negative 500-hPa height anomalies over the entire eastern CONUS. and a 
more amplified trough over the North Pacific. The official manual 500-hPa blend 
weights the ECMWF model the most, due to recent greater anomaly correlation 
skill scores. The manual blend of 500-hPa heights for week 2 is similar to the 
circulation pattern forecast for the 6-10 day period indicating weak positive 
500-hPa height anomalies over most of the CONUS. Weak positive 500-hPa height 
anomalies are predicted over the Northeast, under a weakening trough, and 
greater positive 500-hPa height anomalies are indicated over the northwest 
CONUS and Northern Plains, as the ridge is predicted to increase in amplitude 
over this region. 

The temperature forecast for the week 2 period indicates increased 
probabilities of above normal temperatures for the Pacific Northwest, under 
predicted increasing 500-hPa heights, and lower probabilities of above normal 
temperatures for the northern central CONUS as a ridge over the region in the 
6-10 day period forecast is expected to shift westward in week 2. Enhanced 
probabilities of below normal precipitation expand in parts of Colorado and 
Arizona as well as for much of the Southern Plains into the Central Mississippi 
Valley, related to an enhanced probability of above normal precipitation for 
these regions. The temperature forecast for Alaska is similar in week 2 to the 
6-10 day forecast, with above normal temperatures most likely along the coasts 
and near to below normal temperatures more likely in the Alaska interior. 

Overall the predicted precipitation pattern for week 2 is similar to the 
forecast for the 6-10 day period. Probabilities of above normal precipitation 
are enhanced from eastern Texas into the the Central Mississippi Valley and the 
Tennessee and Ohio Valleys, as moisture continues to be expected to be drawn 
northward from the Gulf of Mexico at low levels. Probabilities of above normal 
precipitation are slightly enhanced for much of the central CONUS with the 
potential development of storm systems across the region east of the Rockies. 
Near to below normal precipitation continues to be likely west of the Rockies 
in week 2, with some potential for small precipitation amounts, ahead of a 
trough over the Pacific Ocean, as indicated by some of the tools. Probabilities 
of above normal precipitation continue to be enhanced for Alaska outside of the 
Alaska Panhandle, ahead of a predicted trough over the Bering Sea and with 
nearby above normal sea surface temperatures. 

The official 8-14 day 500-hPa height blend consists of: 20% of Today's 6z GFS 
Ensemble Mean centered on Day 11, 50% 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: About average, 3 out of 5, due to 
fair agreement among the model circulation forecasts and among the temperature 
and precipitation tools, offset by increasing uncertainty with longer lead 
times.

FORECASTER: D Collins

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 
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: 
19750619 - 19560629 - 19980626 - 19890626 - 20000708


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: 
19980627 - 19620615 - 19750618 - 19890627 - 20080614


6-10 DAY OUTLOOK TABLE
Outlook for Jun 30 - Jul 04, 2019

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    N     OREGON      A    B     NRN CALIF   B    N     
SRN CALIF   A    N     IDAHO       A    B     NEVADA      N    N     
W MONTANA   A    N     E MONTANA   A    A     WYOMING     A    A     
UTAH        A    B     ARIZONA     A    B     COLORADO    A    A     
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    A     
NEBRASKA    A    A     KANSAS      A    B     OKLAHOMA    A    A     
N TEXAS     B    A     S TEXAS     N    A     W TEXAS     A    B     
MINNESOTA   A    A     IOWA        A    A     MISSOURI    A    A     
ARKANSAS    N    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    N    N     
VERMONT     N    N     NEW HAMP    N    N     MAINE       N    A     
MASS        N    N     CONN        N    N     RHODE IS    N    N     
PENN        A    B     NEW JERSEY  A    B     W VIRGINIA  A    N     
MARYLAND    A    B     DELAWARE    A    B     VIRGINIA    A    B     
N CAROLINA  A    B     S CAROLINA  A    N     GEORGIA     A    N     
FL PNHDL    A    N     FL PENIN    A    N     AK N SLOPE  N    A     
AK ALEUTIAN A    A     AK WESTERN  A    A     AK INT BSN  B    A     
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    B     
 
                           

8-14 DAY OUTLOOK TABLE
Outlook for Jul 02 - 08 2019

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

$$