6-10 Day Narrative

805 
FXUS06 KWBC 131916
PMDMRD
Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks
NWS Climate Prediction Center College Park, MD
300 PM EDT Tue August 13 2019
6-10 DAY OUTLOOK FOR AUG 19 - 23 2019
Model solutions are in good agreement in predicting an upper-level amplified 
trough over the western Aleutians. Downstream, model solutions continue to 
indicate a weak 500-hPa ridge over the west-central CONUS, and a weak trough 
over the eastern CONUS. The resultant of manual blend indicates negative 
500-hPa height anomalies over much of Alaska, while positive 500-hPa height 
anomalies are predicted over most of the CONUS.
A broad subtropical ridge favors enhanced probabilities of near to above normal 
temperatures throughout much of the CONUS, except for parts of the Northern 
Rockies and the Northern Plains in association with cold air advection from 
northwestern Canada. Above normal temperatures are likely across the southwest 
coast of mainland Alaska, the Aleutians, and parts of the Alaska Panhandle due 
to anomalous southerly surface flow during the period and above normal SSTs in 
soundings. Below normal temperatures are favored over east-central mainland 
Alaska underneath below normal 500-hPa heights over the region. 
A prolonged break in the monsoon is likely during mid to late August. Near to 
below normal precipitation is likely across parts of the Southwest, Great Basin 
eastward to the Central and Southern Plains as a 500-hPa ridge becomes centered 
well south of the Four Corners region and northwesterly flow prevails. The 
ridge aloft is likely to suppress convection across most of Texas. Potential 
frontal activity forecast to enhance convection, which favors above normal 
precipitation over the parts of the Northern Plain, and the Mississippi Valley. 
Predicted mean southerly flow and associated moisture advection increase 
chances for above normal precipitation across the Gulf Coast to much of the 
eastern CONUS. Near to below normal precipitation is favored for much of 
mainland Alaska, consistent with the forecast consolidation tool. Above normal 
precipitation probabilities are increased over parts of the south coast of 
mainland Alaska, the Aleutians and the Alaska Panhandle underneath near to 
below normal 500-hPa heights.
The official 6-10 day 500-hPa height blend consists of 20% of Today's 0z GFS 
Ensemble Mean centered on Day 8, 20% of Today's 6z GFS Ensemble Mean centered 
on Day 8, 20% of Today's GFS Superensemble Mean centered on Day 8, 20% of 
Today's 0z European Ensemble Mean centered on Day 8, and 20% of Yesterday's 12z 
European Ensemble Mean centered on Day 7 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Above average, 4 out of 5, due to 
good model consistency and a well established longwave pattern.
8-14 DAY OUTLOOK FOR AUG 21 - 27 2019 
During Week-2, the predicted 500-hPa circulation pattern is similar to the 
pattern for the 6-10 day period. The ensemble means remain in good agreement 
today and feature an amplified 500-hPa pattern at the higher latitudes of the 
Northern Hemisphere. An upper-level trough is likely to persist across the 
Aleutians, while mostly zonal flow is forecast across much of mainland Alaska. 
Weak 500-hPa height anomalies are predicted over most of the CONUS except for 
the Northeast and parts of the northern CONUS where above normal heights are 
favored.  
Below normal temperatures are likely to persist over the northern Rockies due 
to the forecast trough over northwestern Canada. The subtropical ridge is 
likely to expand north and east during Week-2, increasing the probabilities for 
near to above normal temperatures across the western to the central and eastern 
CONUS. The highest probabilities of above normal temperatures continue to be 
forecast for the southern High Plains, Southern Rockies, the Southwest, and the 
Northeast based on the anomalous subtropic ridge aloft and underneath predicted 
above normal 500-hPa heights over the Northeast. Below normal temperatures are 
likely across parts of eastern mainland Alaska underneath below normal 500-hPa 
heights, while above normal temperatures are likely to persist for the 
remainder of the state, consistent with consolidation forecast tool and above 
normal SSTs in surrounding areas.
The suppressed monsoon is likely to persist for much of Week-2 with the 500-hPa 
ridge axis extending from the Desert Southwest eastward to parts of the 
southern Great Plains. The predicted 500-hPa height pattern and influx of 
anomalous moisture result in increased chances of above normal precipitation 
from the Pacific Northwest extending east into parts of the northern Plains, 
the upper-Mississippi Valley, and parts of the Great Lakes. The enhanced odds 
for above normal precipitation forecast across parts of the Lower Mississippi 
Valley and Southeast are related to a weakening front at the beginning of 
Week-2. Below normal precipitation is favored for the far Northeast, consistent 
with the consolidation forecast tool. Near to above normal precipitation is 
favored for Alaska in association with storm systems forecast near southern 
Alaska.
The official 8-14 day 500-hPa height blend consists of: 20% of Today's 0z GFS 
Ensemble Mean centered on Day 11, 20% of Today's 6z GFS Ensemble Mean centered 
on Day 11, 20% of Today's GFS Superensemble Mean centered on Day 11, 20% of 
Today's 0z European Ensemble Mean centered on Day 11, and 20% of Yesterday's 
12z European Ensemble Mean centered on Day 10 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Average, 3 out of 5, due to good 
agreement among the ensemble means on the longwave pattern but offset by weak 
signals in the precipitation tools.
FORECASTER: Qin Z
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 
August 15.
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: 
19620726 - 19870821 - 19560728 - 19930806 - 19780825
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: 
19620726 - 19560727 - 19780825 - 19870821 - 19670726
6-10 DAY OUTLOOK TABLE
Outlook for Aug 19 - 23 2019
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N     
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N     
W MONTANA   N    N     E MONTANA   N    N     WYOMING     A    B     
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B     
NEW MEXICO  A    B     N DAKOTA    N    A     S DAKOTA    A    N     
NEBRASKA    A    B     KANSAS      A    B     OKLAHOMA    A    B     
N TEXAS     A    B     S TEXAS     A    B     W TEXAS     A    B     
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    N     
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A     
TENNESSEE   A    A     ALABAMA     A    A     NEW YORK    A    A     
VERMONT     A    N     NEW HAMP    A    N     MAINE       A    N     
MASS        A    N     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    A     FL PENIN    A    A     AK N SLOPE  B    B     
AK ALEUTIAN A    A     AK WESTERN  A    B     AK INT BSN  B    B     
AK S INT    B    N     AK SO COAST A    N     AK PNHDL    N    A     
 
                           
8-14 DAY OUTLOOK TABLE
Outlook for Aug 21 - 27 2019
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    N     OREGON      A    N     NRN CALIF   A    N     
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N     
W MONTANA   B    A     E MONTANA   B    A     WYOMING     A    N     
UTAH        A    B     ARIZONA     A    B     COLORADO    A    B     
NEW MEXICO  A    B     N DAKOTA    A    A     S DAKOTA    A    A     
NEBRASKA    A    N     KANSAS      A    N     OKLAHOMA    A    A     
N TEXAS     A    A     S TEXAS     A    N     W TEXAS     A    B     
MINNESOTA   A    A     IOWA        A    N     MISSOURI    N    A     
ARKANSAS    N    A     LOUISIANA   N    A     WISCONSIN   A    N     
ILLINOIS    A    N     MISSISSIPPI N    A     MICHIGAN    A    A     
INDIANA     A    A     OHIO        A    A     KENTUCKY    A    A     
TENNESSEE   A    A     ALABAMA     N    A     NEW YORK    A    N     
VERMONT     A    B     NEW HAMP    A    B     MAINE       A    B     
MASS        A    N     CONN        A    N     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    A     FL PENIN    A    A     AK N SLOPE  N    N     
AK ALEUTIAN A    A     AK WESTERN  A    N     AK INT BSN  N    N     
AK S INT    A    A     AK SO COAST A    A     AK PNHDL    A    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.
$$