859  
FXUS06 KWBC 232038  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST FRI FEBRUARY 23 2018  
 
6-10 DAY OUTLOOK FOR MAR 01 - 05 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED  
LARGE SCALE 500-HPA CIRCULATION PATTERN IN THE 6-10 DAY PERIOD. A HIGH  
AMPLITUDE RIDGE IS PREDICTED OVER WESTERN ALASKA. DOWNSTREAM, A STRONG TROUGH  
IS PREDICTED ALONG THE WEST COAST WITH A RIDGE OVER EAST-CENTRAL NORTH AMERICA.  
TODAY'S MANUAL 500-HPA BLEND IS BASED PRIMARILY ON THE ENSEMBLE MEANS FROM THE  
CANADIAN, EUROPEAN, AND GEFS MODEL SUITES. BELOW NORMAL 500-HPA HEIGHTS ARE  
FORECAST FOR THE WESTERN CONUS, PARTS OF THE NORTHERN AND CENTRAL PLAINS, PARTS  
OF THE EAST COAST, AND THE SOUTHERN ALASKA PANHANDLE, WHILE NEAR TO ABOVE  
NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO INCREASED CHANCES OF BELOW  
NORMAL TEMPERATURES FOR THE WESTERN CONUS. A RIDGE FORECAST OVER EAST-CENTRAL  
NORTH AMERICA LEADS TO ENHANCED CHANCES OF ABOVE NORMAL TEMPERATURES FOR THE  
MUCH OF EASTERN CONUS AND THE SOUTHERN PLAINS. ANOMALOUS RIDGING OVER WESTERN  
ALASKA FAVORS NEAR TO ABOVE NORMAL TEMPERATURES FOR EXTREME WESTERN MAINLAND  
ALASKA AS WELL AS THE ALEUTIANS. ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO  
NEAR TO BELOW NORMAL TEMPERATURES FOR EASTERN MAINLAND ALASKA AND THE ALASKA  
PANHANDLE.  
 
THE DEEP TROUGH FORECAST OVER THE WESTERN CONUS AND/OR ANOMALOUS SOUTHWESTERLY  
FLOW ENHANCE PROBABILITIES OF NEAR TO ABOVE NORMAL PRECIPITATION OVER MUCH OF  
THE CONUS, EXCEPT FOR PARTS OF SOUTHERN ROCKIES, THE SOUTHERN PLAINS, AND  
FLORIDA WHERE BELOW NORMAL PRECIPITATION IS INDICATED, CONSISTENT WITH THE GEFS  
AND ECMWF REFORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR WESTERN  
ALASKA, WHILE BELOW NORMAL PRECIPITATION IS FORECAST FOR NORTHEASTERN ALASKA,  
CONSISTENT WITH DYNAMICAL MODEL GUIDANCE FROM THE ECMWF AND GEFS ENSEMBLE MEANS  
SOLUTIONS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 5% OF TODAY'S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 25% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 7, 10% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED  
ON DAY 8, 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 5% OF  
YESTERDAY'S 12Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 7  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
A RELATIVELY AMPLIFIED FLOW PATTERN ACROSS MUCH OF THE FORECAST DOMAIN.  
 
8-14 DAY OUTLOOK FOR MAR 03 - 09 2018  
 
THE MEAN 500-HPA FLOW PATTERN EXPECTED FOR THE WEEK-2 PERIOD FEATURES A LESS  
AMPLIFIED CIRCULATION AND THE OVERALL LONG WAVE PATTERN IS SHIFTED WESTWARD.  
ABOVE NORMAL HEIGHTS ARE EXPECTED OVER ALASKA, PARTS OF THE SOUTHERN PLAINS,  
THE SOUTHERN ROCKIES, THE NORTHERN PLAINS, THE UPPER MISSISSIPPI VALLEY, THE  
GREAT LAKES, AND PARTS OF THE NORTHEAST, WHILE NEAR TO BELOW NORMAL HEIGHTS ARE  
ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
A TROUGH NEAR THE WEST COAST OF THE CONUS AND BELOW NORMAL HEIGHTS LEAD TO  
INCREASED CHANCES OF NEAR TO BELOW NORMAL TEMPERATURES FOR MUCH OF THE WESTERN  
AND CENTRAL CONUS. ENHANCED PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ALSO  
EXPECTED OVER PARTS OF NORTH AND SOUTH CAROLINA, AND VIRGINIA DUE TO EXPECTED  
BELOW NORMAL HEIGHTS AND NORTHERLY FLOW. NEAR TO ABOVE NORMAL TEMPERATURES ARE  
FAVORED FOR NORTHWESTERN MAINLAND ALASKA AS WELL AS THE ALEUTIANS, AND BELOW  
NORMAL TEMPERATURES ARE FAVORED FOR SOUTHEASTERN ALASKA AND THE ALASKA  
PANHANDLE, CONSISTENT WITH TODAY'S DYNAMICAL MODEL GUIDANCE.  
 
THE TROUGH FORECAST NEAR THE WEST COAST OF THE CONUS AND/OR ANOMALOUS  
SOUTHWESTERLY FLOW ENHANCE PROBABILITIES OF ABOVE NORMAL PRECIPITATION OVER  
MUCH OF CALIFORNIA, PARTS OF THE NORTHERN AND CENTRAL PLAINS, AND UPPER AND  
MIDDLE MISSISSIPPI VALLEYS. BELOW NORMAL PRECIPITATION IS INDICATED OVER PARTS  
OF THE CENTRAL AND SOUTHERN ROCKIES, AND THE SOUTHERN AND CENTRAL PLAINS DUE TO  
THE EAST-CENTRAL RIDGE. NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED FOR  
WESTERN ALASKA, WHILE BELOW NORMAL PRECIPITATION IS FORECAST FOR PARTS OF  
EASTERN ALASKA, WESTERN MONTANA, AND PARTS OF THE GREAT LAKES, AND SOUTHEAST  
ACCORDING THE REFORECAST TOOL FROM THE ECMWF ENSEMBLE.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 30% OF TODAY'S  
0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 5% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 10, 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN  
CENTERED ON DAY 11, AND 5% OF YESTERDAY'S 12Z CANADIAN ENSEMBLE MEAN CENTERED  
ON DAY 10  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
FAIRLY GOOD ENSEMBLE MEAN MODEL AGREEMENT OFFSET BY A TRANSITION TO A LESS  
AMPLIFIED PATTERN DURING WEEK-2.  
 
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 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  
MARCH 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:  
19510203 - 19520203 - 19530203 - 19540203 - 19550203  
 
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:  
19510202 - 19520202 - 19530202 - 19540202 - 19550202  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 01 - 05 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B A  
SRN CALIF B A IDAHO B A NEVADA B A  
W MONTANA B N E MONTANA B A WYOMING B A  
UTAH B A ARIZONA B A COLORADO B N  
NEW MEXICO B B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA A A  
N TEXAS A N S TEXAS A N W TEXAS N B  
MINNESOTA A A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A N WISCONSIN A A  
ILLINOIS A A MISSISSIPPI A A MICHIGAN A N  
INDIANA A A OHIO A A KENTUCKY A A  
TENNESSEE A A ALABAMA A N 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 A NEW JERSEY A A W VIRGINIA A A  
MARYLAND A A DELAWARE A A VIRGINIA A A  
N CAROLINA A N S CAROLINA A N GEORGIA A N  
FL PNHDL A N FL PENIN A B AK N SLOPE N N  
AK ALEUTIAN A A AK WESTERN N A AK INT BSN B N  
AK S INT B N AK SO COAST B N AK PNHDL B N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 03 - 09 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B A  
SRN CALIF B N IDAHO B N NEVADA B N  
W MONTANA B B E MONTANA B N WYOMING B N  
UTAH B N ARIZONA B N COLORADO B N  
NEW MEXICO B B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B N OKLAHOMA B B  
N TEXAS N B S TEXAS N B W TEXAS B B  
MINNESOTA B A IOWA B A MISSOURI N N  
ARKANSAS N N LOUISIANA N N WISCONSIN N N  
ILLINOIS N N MISSISSIPPI N N MICHIGAN A B  
INDIANA N N OHIO N N KENTUCKY N N  
TENNESSEE N N ALABAMA N N 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 N N NEW JERSEY N N W VIRGINIA N N  
MARYLAND N N DELAWARE N N VIRGINIA B N  
N CAROLINA B N S CAROLINA B B GEORGIA N B  
FL PNHDL N B FL PENIN N B AK N SLOPE N N  
AK ALEUTIAN N N AK WESTERN N N AK INT BSN B N  
AK S INT B N AK SO COAST B B AK PNHDL B 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.  
 

 
 
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