257  
FXUS06 KWBC 232002  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST TUE JANUARY 23 2018  
 
6-10 DAY OUTLOOK FOR JAN 29 - FEB 02, 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED  
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. A LOW AMPLITUDE BROADLY CYCLONIC  
FLOW PATTERN IS ANTICIPATED ACROSS MUCH OF THE CONUS WITH A WEAK TROUGH  
FORECAST OVER THE WEST-CENTRAL PART OF THE NATION. A RIDGE IS PREDICTED OVER  
THE CARIBBEAN, WHILE TROUGHS ARE EXPECTED NORTHEAST OF HUDSON BAY AND OVER MOST  
OF SOUTHERN AND EASTERN MAINLAND ALASKA. THE ENSEMBLE SPAGHETTI CHARTS DEPICT  
MODERATE SPREAD OVER THE EASTERN CONUS AND MODERATE TO LARGE SPREAD OVER THE  
WESTERN CONUS AND EASTERN PACIFIC. THE AO INDEX WHICH RECENTLY HAS BEEN  
NEGATIVE IS FORECAST TO BE NEAR ZERO AT DAY 7, WEAKLY NEGATIVE AT 10 DAY, AND  
REMAIN NEGATIVE AT DAY 14. THE PNA INDEX WHICH RECENTLY HAS BEEN WEAKLY  
NEGATIVE IS FORECAST TO BE NEAR ZERO AT DAY 7, AND REMAIN CLOSE TO ZERO THROUGH  
DAY 14. TODAY'S 500-HPA BLEND CHART DEPICTS NEAR TO BELOW NORMAL HEIGHTS OVER  
THE NORTHWEST CONUS, THE ALASKA PANHANDLE, AND EXTREME SOUTHEASTERN MAINLAND  
ALASKA, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER  
OF THE FORECAST DOMAIN.  
 
ABOVE NORMAL HEIGHTS ENHANCE PROBABILITIES OF NEAR TO ABOVE NORMAL TEMPERATURES  
FOR MOST OF THE CONUS. THE EXCEPTION IS OVER PARTS OF THE NORTHWESTERN AND  
NORTH-CENTRAL CONUS WHERE BELOW NORMAL HEIGHTS TILT THE ODDS TO NEAR TO BELOW  
NORMAL TEMPERATURES. ANOMALOUS NORTHERLY FLOW ENHANCES PROBABILITIES OF BELOW  
NORMAL TEMPERATURES FOR MUCH OF ALASKA.  
 
THE TROUGH FORECAST OVER THE WEST-CENTRAL CONUS FAVORS ABOVE NORMAL  
PRECIPITATION FOR THE EASTERN THIRD OF THE NATION. BELOW NORMAL HEIGHTS AND/OR  
ANOMALOUS WESTERLY FLOW ENHANCES PROBABILITIES OF ABOVE NORMAL PRECIPITATION  
FOR PARTS OF THE PACIFIC NORTHWEST, THE NORTHERN INTERMOUNTAIN WEST, NORTHERN  
ROCKIES, AND NORTHERN PLAINS. ABOVE NORMAL HEIGHTS AND/OR ANOMALOUS NORTHERLY  
FLOW TILT THE ODDS TO NEAR TO BELOW NORMAL PRECIPITATION FOR THE REMAINDER OF  
THE CONUS AND ALASKA.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 25% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF  
YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, 10% OF TODAY'S 0Z  
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 10% OF YESTERDAY'S 12Z CANADIAN  
ENSEMBLE MEAN CENTERED ON DAY 7  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY  
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS AND FAIR AGREEMENT AMONG THE  
SURFACE TOOLS.  
 
8-14 DAY OUTLOOK FOR JAN 31 - FEB 06, 2018  
 
THE OVERALL CIRCULATION PATTERN IS EXPECTED TO BE SOMEWHAT PROGRESSIVE DURING  
WEEK-2 AS HEIGHTS FALL OVER THE CENTRAL CONUS AND RISE OVER THE PACIFIC  
NORTHWEST. THE TROUGH FORECAST OVER THE WEST-CENTRAL CONUS DURING THE 6-10 DAY  
PERIOD IS ANTICIPATED TO MOVE TO THE CENTRAL CONUS AND AMPLIFY. THE ENSEMBLE  
SPAGHETTI CHARTS CONTINUE TO INDICATE MODERATE SPREAD OVER THE EASTERN CONUS,  
AND MODERATE TO LARGE SPREAD OVER THE WESTERN CONUS AND EASTERN PACIFIC.  
TODAY'S 500-HPA BLENDED HEIGHT CHART DEPICTS NEAR TO BELOW NORMAL HEIGHTS OVER  
PARTS OF THE ROCKIES, THE HIGH PLAINS, THE UPPER AND MIDDLE MISSISSIPPI  
VALLEYS, AND THE GREAT LAKES, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE  
ANTICIPATED OVER THE REMAINDER OF THE CONUS AND ALASKA.  
 
FOR THE CONUS, AREAS THAT ARE EXPECTED TO HAVE NEAR TO ABOVE (BELOW) NORMAL  
HEIGHTS GENERALLY CORRESPOND TO AREAS THAT ARE FORECAST TO HAVE ENHANCED  
PROBABILITIES FOR ABOVE (BELOW) NORMAL TEMPERATURES. ANOMALOUS NORTHERLY FLOW  
TILT THE ODDS TO BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHEASTERN MAINLAND  
ALASKA AND THE ALASKA PANHANDLE. ABOVE NORMAL HEIGHTS FAVOR ABOVE NORMAL  
TEMPERATURES FOR THE ALEUTIANS AND PARTS OF SOUTHWESTERN MAINLAND ALASKA.  
 
THE TROUGH OVER THE CENTRAL U.S. ENHANCES PROBABILITIES OF ABOVE NORMAL  
PRECIPITATION FOR MUCH OF THE CENTRAL AND EASTERN CONUS AS WELL AS PORTIONS OF  
THE NORTHERN AND CENTRAL ROCKIES AND NORTHERN AND CENTRAL PLAINS. ABOVE NORMAL  
HEIGHTS AND/OR ANOMALOUS NORTH/NORTHWESTERLY FLOW FAVORS BELOW NORMAL  
PRECIPITATION FOR PARTS OF THE WESTERN AND SOUTHWESTERN CONUS. ANOMALOUS  
NORTHERLY FLOW TILTS THE ODDS TO BELOW NORMAL PRECIPITATION FOR NORTHEASTERN  
ALASKA AND THE ALASKA PANHANDLE, WHILE ANOMALOUS SOUTHERLY FLOW ENHANCES  
PROBABILITIES FOR ABOVE NORMAL PRECIPITATION FOR THE ALEUTIANS AND PARTS OF  
SOUTHWESTERN MAINLAND ALASKA.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% 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, 15% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF YESTERDAY'S 12Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, 10% OF TODAY'S 0Z CANADIAN ENSEMBLE  
MEAN CENTERED ON DAY 11, AND 10% 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  
GOOD AGREEMENT AMONG THE ENSEMBLE MODEL SOLUTIONS OFFSET BY MODERATE TO HIGH  
SPREAD AMONG ENSEMBLE MEMBERS.  
 
FORECASTER: RANDY S  
 
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  
FEBRUARY 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:  
19990128 - 19510121 - 19540126 - 20000111 - 19680112  
 
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:  
19680112 - 19990128 - 19510121 - 20080110 - 19590110  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 29 - FEB 02, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON N A NRN CALIF A B  
SRN CALIF A B IDAHO N A NEVADA A B  
W MONTANA B A E MONTANA B A WYOMING N A  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA B A S DAKOTA N A  
NEBRASKA A N KANSAS A B OKLAHOMA A B  
N TEXAS A B S TEXAS N B W TEXAS A B  
MINNESOTA N A IOWA A A MISSOURI A A  
ARKANSAS A N LOUISIANA A N 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 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 A AK N SLOPE N B  
AK ALEUTIAN B B AK WESTERN B B AK INT BSN B B  
AK S INT B B AK SO COAST B B AK PNHDL B B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 31 - FEB 06, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B B OREGON B B NRN CALIF A B  
SRN CALIF A B IDAHO B N NEVADA A B  
W MONTANA B A E MONTANA B A WYOMING B A  
UTAH A N ARIZONA A B COLORADO N N  
NEW MEXICO A B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B A OKLAHOMA N N  
N TEXAS A N S TEXAS A N W TEXAS A B  
MINNESOTA B A IOWA B A MISSOURI N A  
ARKANSAS A A LOUISIANA A A WISCONSIN B A  
ILLINOIS N A MISSISSIPPI A A MICHIGAN N A  
INDIANA N 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 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 A AK N SLOPE N B  
AK ALEUTIAN A A AK WESTERN N N AK INT BSN N B  
AK S INT N N AK SO COAST A N 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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