166  
FXUS06 KWBC 062025  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST TUE FEBRUARY 06 2018  
 
6-10 DAY OUTLOOK FOR FEB 12 - 16 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED  
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. A DEEP CLOSED-OFF TROUGH IS  
ANTICIPATED NORTH OF HUDSON BAY, EXTENDING SOUTHWESTWARD OVER THE SOUTHWEST  
CONUS LEADING TO A BROADLY CYCLONIC FLOW PATTERN ACROSS MOST OF THE CONUS. A  
RIDGE IS PREDICTED OVER THE EAST PACIFIC, WHILE A TROUGH IS FORECAST OVER THE  
ALEUTIANS. A SUBTROPICAL RIDGE IS FORECAST TO BE CENTERED OVER FLORIDA AND THE  
SOUTHERN GULF OF MEXICO. TODAY'S MANUAL 500-HPA BLEND IS BASED PRIMARILY ON THE  
ENSEMBLE MEANS FROM THE CANADIAN, EUROPEAN, AND GEFS MODEL SUITES. THE  
RESULTANT MANUAL BLEND DEPICTS NEAR TO BELOW NORMAL HEIGHTS OVER PARTS OF THE  
NORTHERN ROCKIES, THE NORTHERN PLAINS, AND THE UPPER MISSISSIPPI VALLEY, WHILE  
NEAR TO ABOVE NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST  
DOMAIN.  
 
BELOW NORMAL HEIGHTS ENHANCE PROBABILITIES OF BELOW NORMAL TEMPERATURES FOR  
PARTS OF THE NORTHERN ROCKIES AND THE NORTHERN PLAINS. NEAR TO ABOVE NORMAL  
HEIGHTS AND RIDGING FAVOR NEAR TO ABOVE NORMAL TEMPERATURES FOR MUCH OF THE  
SOUTHWESTERN AND EASTERN CONUS. ANOMALOUS SOUTHERLY FLOW TILTS THE ODDS TO  
ABOVE NORMAL TEMPERATURES FOR MUCH OF ALASKA.  
 
THE BROAD TROUGH FORECAST OVER THE CONUS ENHANCES PROBABILITIES OF NEAR TO  
ABOVE NORMAL PRECIPITATION OVER THE SOUTHWEST, THE SOUTHERN ROCKIES, THE  
SOUTHERN PLAINS, AND THE EASTERN CONUS, EXCEPT FOR FLORIDA WHERE BELOW NORMAL  
PRECIPITATION IS INDICATED. UPSLOPE FLOW TILTS THE ODDS FOR NEAR TO ABOVE  
NORMAL PRECIPITATION FOR MUCH OF MONTANA. THE RIDGE UPSTREAM OVER THE NORTHEAST  
PACIFIC AND ABOVE NORMAL HEIGHTS TILT THE ODDS TO NEAR TO BELOW NORMAL  
PRECIPITATION FOR THE WEST COAST OF THE CONUS. BELOW NORMAL PRECIPITATION IS  
ALSO FAVORED FOR PARTS OF THE NORTHERN AND CENTRAL PLAINS CONSISTENT WITH  
DYNAMICAL MODEL GUIDANCE FROM THE ECMWF ENSEMBLE MEANS SOLUTIONS. THE TROUGH  
OVER THE ALEUTIANS FAVORS ABOVE NORMAL PRECIPITATION FOR ALASKA.  
 
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  
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS AND VARIOUS TOOLS FOR MUCH OF  
THE FORECAST DOMAIN.  
 
8-14 DAY OUTLOOK FOR FEB 14 - 20 2018  
 
THE MEAN 500-HPA FLOW PATTERN EXPECTED FOR THE WEEK-2 PERIOD IS SIMILAR TO THAT  
DEPICTED FOR THE 6 TO 10 DAY TIME FRAME WITH A TROUGH OVER THE CONUS, A RIDGE  
OVER THE EAST PACIFIC, AND A SUBTROPICAL RIDGE REMAINING OVER THE GULF OF  
MEXICO. THE ENSEMBLE SPAGHETTI CHARTS INDICATE MODERATE TO LARGE SPREAD OVER  
OVER MUCH OF THE FORECAST DOMAIN. NEAR TO ABOVE NORMAL HEIGHTS ARE FORECAST  
ACROSS MOST OF THE CONUS AND ALASKA, WHILE NEAR TO BELOW NORMAL HEIGHTS ARE  
ANTICIPATED OVER PARTS OF NORTH DAKOTA AND MINNESOTA.  
 
ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TOWARD BELOW NORMAL TEMPERATURES FOR  
MONTANA. ABOVE NORMAL HEIGHTS FAVOR NEAR TO ABOVE NORMAL TEMPERATURES FOR MUCH  
OF THE CONUS. ANOMALOUS SOUTHERLY FLOW ENHANCES PROBABILITIES OF NEAR TO ABOVE  
NORMAL TEMPERATURES FOR MUCH OF ALASKA CONSISTENT WITH CALIBRATED GEFS AND  
ECMWF GUIDANCE.  
 
THE TROUGH FORECAST OVER THE CONUS AND RETURN FLOW FROM THE GULF OF MEXICO  
ENHANCE PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR PARTS OF THE SOUTHWEST,  
THE SOUTHERN ROCKIES, THE SOUTHERN PLAINS, THE LOWER AND MIDDLE MISSISSIPPI  
VALLEY, THE TENNESSEE VALLEY, THE OHIO VALLEY, THE LOWER GREAT LAKES, THE  
MIDDLE ATLANTIC, AND THE NORTHEAST. MODELS DEPICT A STRONGER TROUGH OVER THE  
NORTH-CENTRAL CONUS RESULTING IN THE REDUCTION OF DRY AREAS OVER THE EASTERN  
CONUS RELATIVE TO YESTERDAY. UPSLOPE FLOW TILTS THE ODDS FOR NEAR TO ABOVE  
NORMAL PRECIPITATION FOR PARTS OF THE NORTHERN HIGH PLAINS AND NORTHERN  
ROCKIES. RIDGES AND ABOVE NORMAL HEIGHTS FAVOR NEAR TO BELOW NORMAL  
PRECIPITATION FOR THE REMAINDER OF THE CONUS. THE TROUGH OVER THE ALEUTIANS  
TILTS THE ODDS TO ABOVE NORMAL PRECIPITATION FOR ALASKA.  
 
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: BELOW AVERAGE, 2 OUT OF 5, DUE TO  
FAIR AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFF-SET BY MODERATE TO LARGE  
SPREAD AMONG ENSEMBLE MEMBERS OVER MUCH OF THE FORECAST DOMAIN.  
 
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  
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:  
19630122 - 19840119 - 19630117 - 19910128 - 20030209  
 
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:  
19840119 - 19630118 - 19630123 - 19910127 - 19510131  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 12 - 16 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON N B OREGON N B NRN CALIF A B  
SRN CALIF A N IDAHO N N NEVADA A B  
W MONTANA B A E MONTANA B A WYOMING N N  
UTAH N N ARIZONA A A COLORADO N N  
NEW MEXICO A A N DAKOTA B N S DAKOTA N B  
NEBRASKA N B KANSAS N N OKLAHOMA N A  
N TEXAS N A S TEXAS N A W TEXAS N A  
MINNESOTA N N IOWA N N MISSOURI N A  
ARKANSAS A A LOUISIANA A N WISCONSIN N N  
ILLINOIS N A MISSISSIPPI A A MICHIGAN N N  
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 N FL PENIN A B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A  
AK S INT A A AK SO COAST A A AK PNHDL N A  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 14 - 20 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON N B OREGON A B NRN CALIF A B  
SRN CALIF A N IDAHO A B NEVADA A B  
W MONTANA B A E MONTANA B A WYOMING N B  
UTAH A B ARIZONA A A COLORADO A N  
NEW MEXICO A A N DAKOTA N N S DAKOTA N N  
NEBRASKA N B KANSAS A N OKLAHOMA A A  
N TEXAS A A S TEXAS A N W TEXAS A A  
MINNESOTA N N IOWA N B MISSOURI A A  
ARKANSAS A A LOUISIANA A B WISCONSIN N N  
ILLINOIS A N MISSISSIPPI A N MICHIGAN N N  
INDIANA A A OHIO A A KENTUCKY A A  
TENNESSEE A A ALABAMA A B NEW YORK A A  
VERMONT A A NEW HAMP A A MAINE A N  
MASS A A CONN A A RHODE IS A A  
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 B GEORGIA A B  
FL PNHDL A B FL PENIN A B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A  
AK S INT N A AK SO COAST N A AK PNHDL N 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.  
 

 
 
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