6-10 Day Narrative

889 
FXUS06 KWBC 161902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED AUGUST 16 2017
6-10 DAY OUTLOOK FOR AUG 22 - 26 2017
TODAY'S DYNAMICAL MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED 
MID-TROPOSPHERIC FLOW PATTERN. TODAY'S MODELS HAVE TRENDED TOWARD A HIGHER 
AMPLITUDE 500-HPA PATTERN OVER THE FORECAST DOMAIN THAN YESTERDAY. MODELS 
PREDICT TROUGHS OVER MUCH OF ALASKA, OFF THE WESTERN COAST OF THE CONUS, AND 
OVER EASTERN CANADA AND THE NORTHEASTERN U.S. TODAY'S MANUAL 500-HPA HEIGHT 
BLEND SHOWS POSITIVE HEIGHT ANOMALIES OVER PARTS OF THE NORTHERN PLAINS, 
NEGATIVE HEIGHT ANOMALIES OVER THE GREAT LAKES REGION AND THE NORTHEAST, AND 
NEAR NORMAL HEIGHT ELSEWHERE IN THE COUNTRY.
ODDS OF BELOW NORMAL TEMPERATURES ARE ELEVATED OVER MOST OF ALASKA DUE TO A 
PREDICTED NEARBY TROUGH. POSITIVE TEMPERATURE ANOMALIES FORECAST DURING THE 
FIRST HALF OF THE 6-10 DAY PERIOD FAVOR INCREASED CHANCES OF ABOVE NORMAL 
TEMPERATURES FOR THE EAST COAST. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR 
PARTS OF THE SOUTHERN PLAINS DUE TO SUBTROPICAL RIDGING. ABOVE NORMAL 
TEMPERATURES ARE FAVORED FOR NORTHERN CALIFORNIA TO THE SOUTH OF AN ANTICIPATED 
FRONTAL BOUNDARY OVER THE NORTHWESTERN CONUS. 
ABOVE NORMAL PRECIPITATION IS LIKELY FOR MUCH OF THE EASTERN HALF OF THE CONUS 
DUE TO THE FORECAST PASSAGE OF A STRONG COLD FRONT WITH ASSOCIATED RAINFALL. 
BELOW NORMAL PRECIPITATION IS FAVORED OVER PARTS OF TEXAS DUE TO FORECAST 
SUBTROPICAL RIDGING. NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED FOR PARTS OF 
THE SOUTHWEST DUE TO INCREASED MONSOON ACTIVITY, AND FOR THE GREAT BASIN DUE TO 
SOME PREDICTED TROUGH ENERGY IN THE AREA. THERE ARE INCREASED ODDS FOR ABOVE 
NORMAL PRECIPITATION FOR EXTREME NORTHWEST PORTIONS OF THE PACIFIC NORTHWEST 
NEAR A MEAN TROUGH. BELOW NORMAL PRECIPITATION IS FAVORED FARTHER FROM THE 
TROUGH AXIS FOR PARTS OF THE NORTHERN AND CENTRAL HIGH PLAINS. ABOVE NORMAL 
PRECIPITATION IS ALSO FAVORED FOR EASTERN MAINLAND ALASKA AND THE PANHANDLE 
AHEAD OF A TROUGH WHILE BELOW NORMAL PRECIPITATION IS FAVORED BEHIND THE TROUGH 
AXIS FOR PARTS OF SOUTHWESTERN ALASKA AND THE ALEUTIANS.
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 40% OF TODAY'S 6Z GFS ENSEMBLE MEAN 
CENTERED ON DAY 8, 30% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, AND 30% 
OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO 
FAIRLY GOOD MODEL AGREEMENT, WITH SOME DISAGREEMENT AMONG THE TEMPERATURE TOOLS
8-14 DAY OUTLOOK FOR AUG 24 - 30 2017 
DURING THE WEEK-2 PERIOD, A LESS AMPLIFIED PATTERN IS EXPECTED. THE TROUGH 
FORECAST IN THE EASTERN PACIFIC DURING THE 6-10 DAY PERIOD IS PREDICTED TO 
RETROGRADE BY THE WEEK-2 PERIOD, WITH THE LARGEST NEGATIVE HEIGHT ANOMALIES 
FORECAST SOUTH OF THE ALEUTIANS. THE RIDGE IN THE WESTERN U.S. DURING THE 6-10 
DAY PERIOD IS FORECAST TO BROADEN BY THE WEEK-2 PERIOD, SO THAT MOST OF THE 
WESTERN HALF OF THE CONUS IS PREDICTED TO BE UNDER POSITIVE HEIGHT ANOMALIES. 
THE EASTERN TROUGH IS EXPECTED TO DEEPEN SLIGHTLY, COMPARED TO THE 6-10 DAY 
PERIOD.
THE TEMPERATURE PROBABILITY FORECAST DURING THE WEEK-2 PERIOD IS SIMILAR TO THE 
6-10 DAY PERIOD, WITH A COUPLE EXCEPTIONS. 500-HPA HEIGHTS ARE EXPECTED TO 
BUILD OVER MUCH OF ALASKA, LIMITING BELOW NORMAL TEMPERATURES AND INTRODUCING 
MORE ABOVE NORMAL TEMPERATURES BY THE WEEK-2 PERIOD. WITH THE EASTERN TROUGH 
EXPECTED TO SHIFT EASTWARD AND DEEPEN BY THE WEEK-2 PERIOD, BELOW NORMAL 
TEMPERATURES ARE FAVORED FOR MUCH OF THE EASTERN HALF OF THE COUNTRY.
DURING THE WEEK-2 PERIOD, INCREASED POSITIVE HEIGHT ANOMALIES OVER MAINLAND 
ALASKA FAVOR NEAR TO BELOW NORMAL PRECIPITATION, THOUGH A FEW PREDICTED STORM 
SYSTEMS STILL FAVOR ABOVE NORMAL PRECIPITATION FOR THE ALASKA PANHANDLE DURING 
THE WEEK-2 PERIOD. DUE TO FORECASTED RIDGING, NEAR TO BELOW NORMAL 
PRECIPITATION IS FAVORED FOR THE NORTHERN TIER OF THE CONUS. A FORECAST 
INCREASE IN ANOMALOUS SOUTHERLY LOW-LEVEL FLOW OVER THE SOUTHERN AND CENTRAL 
PLAINS INCREASES THE LIKELIHOOD FOR ABOVE NORMAL PRECIPITATION IN THOSE AREAS. 
A REMNANT TROUGH FORECAST NEAR THE GULF COAST FAVORS ABOVE NORMAL PRECIPITATION 
FOR PARTS OF THE SOUTHEAST.
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 40% OF TODAY'S OPERATIONAL 6Z 
GFS CENTERED ON DAY 11, AND 60% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED 
ON DAY 11 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE 
TO FAIRLY GOOD MODEL AGREEMENT, WITH SOME DISAGREEMENT AMONG THE TEMPERATURE 
TOOLS
FORECASTER: MIKE C
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 17
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: 
19640818 - 19800814 - 19690817 - 19660810 - 19560827
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: 
19660810 - 19640817 - 19620820 - 19560827 - 19800814
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 22 - 26 2017
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    N     OREGON      A    A     NRN CALIF   A    N     
SRN CALIF   N    N     IDAHO       A    A     NEVADA      A    A     
W MONTANA   A    N     E MONTANA   A    N     WYOMING     A    N     
UTAH        A    A     ARIZONA     A    N     COLORADO    A    A     
NEW MEXICO  A    A     N DAKOTA    A    B     S DAKOTA    A    B     
NEBRASKA    N    N     KANSAS      N    A     OKLAHOMA    N    A     
N TEXAS     A    N     S TEXAS     A    B     W TEXAS     A    N     
MINNESOTA   N    B     IOWA        N    A     MISSOURI    N    A     
ARKANSAS    N    A     LOUISIANA   A    A     WISCONSIN   N    B     
ILLINOIS    N    A     MISSISSIPPI A    A     MICHIGAN    N    A     
INDIANA     N    A     OHIO        N    A     KENTUCKY    N    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    N     AK N SLOPE  B    N     
AK ALEUTIAN A    B     AK WESTERN  B    B     AK INT BSN  B    A     
AK S INT    B    B     AK SO COAST B    B     AK PNHDL    B    A     
 
                           
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 24 - 30 2017
STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN   
WASHINGTON  A    B     OREGON      A    B     NRN CALIF   A    N     
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    N     
W MONTANA   A    B     E MONTANA   A    N     WYOMING     A    N     
UTAH        A    N     ARIZONA     A    N     COLORADO    A    N     
NEW MEXICO  A    A     N DAKOTA    A    N     S DAKOTA    A    N     
NEBRASKA    A    N     KANSAS      B    A     OKLAHOMA    B    A     
N TEXAS     N    A     S TEXAS     A    A     W TEXAS     A    A     
MINNESOTA   N    B     IOWA        B    B     MISSOURI    B    A     
ARKANSAS    B    A     LOUISIANA   A    A     WISCONSIN   N    B     
ILLINOIS    B    B     MISSISSIPPI B    A     MICHIGAN    N    B     
INDIANA     B    B     OHIO        B    B     KENTUCKY    B    N     
TENNESSEE   B    A     ALABAMA     B    A     NEW YORK    B    B     
VERMONT     N    N     NEW HAMP    N    N     MAINE       N    N     
MASS        N    N     CONN        N    N     RHODE IS    N    N     
PENN        B    N     NEW JERSEY  B    N     W VIRGINIA  B    N     
MARYLAND    B    N     DELAWARE    B    N     VIRGINIA    B    N     
N CAROLINA  B    A     S CAROLINA  B    A     GEORGIA     A    A     
FL PNHDL    A    A     FL PENIN    A    N     AK N SLOPE  N    N     
AK ALEUTIAN A    B     AK WESTERN  A    B     AK INT BSN  N    N     
AK S INT    N    N     AK SO COAST N    N     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.
$$