614  
FXUS06 KWBC 192001  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST MON FEBRUARY 19 2018  
 
6-10 DAY OUTLOOK FOR FEB 25 - MAR 01, 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE EXPECTED 500-HPA  
FLOW PATTERN OVER THE FORECAST DOMAIN. A DEEP TROUGH IS FORECAST NORTHWEST OF  
HUDSON BAY EXTENDING EAST/SOUTHEAST OVER THE NORTH ATLANTIC, AND SOUTHWESTWARD  
OVER THE WESTERN CONUS. RIDGES ARE ANTICIPATED OVER THE GULF OF MEXICO AND  
WESTERN MAINLAND ALASKA. THE FLOW PATTERN IS PREDICTED TO BE RELATIVELY  
AMPLIFIED. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE SMALL TO MODERATE SPREAD  
ACROSS THE MAJORITY OF THE FORECAST DOMAIN. 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 ABOVE NORMAL HEIGHTS  
OVER MOST OF THE EASTERN CONUS, THE SOUTHERN PLAINS, THE ALEUTIANS, AND  
SOUTHWESTERN MAINLAND ALASKA, AND NEAR TO BELOW NORMAL HEIGHTS OVER MUCH OF THE  
WESTERN CONUS, THE NORTHERN PLAINS, NORTHEASTERN MAINLAND ALASKA, AND THE  
ALASKA PANHANDLE.  
 
PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO INCREASED CHANCES FOR BELOW  
NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS. A STRONG  
RIDGE FORECAST OVER THE SOUTHEASTERN U.S. LEADS TO ENHANCED CHANCES OF ABOVE  
NORMAL TEMPERATURES FOR THE EASTERN CONUS AND THE SOUTHERN PLAINS. ANOMALOUS  
RIDGING OVER SOUTHWESTERN ALASKA FAVORS NEAR TO ABOVE NORMAL TEMPERATURES FOR  
MUCH OF WESTERN AND NORTHERN MAINLAND ALASKA AS WELL AS THE ALEUTIANS.  
ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO NEAR TO BELOW NORMAL TEMPERATURES  
FOR SOUTHEASTERN 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 PARTS OF  
THE SOUTHERN PLAINS, AND MOST OF THE EASTERN CONUS, EXCEPT FOR FLORIDA WHERE  
BELOW NORMAL PRECIPITATION IS INDICATED DUE TO THE HIGHLY ANOMALOUS SOUTHEAST  
RIDGE. BELOW NORMAL PRECIPITATION IS ALSO FAVORED FOR PARTS OF THE HIGH PLAINS,  
AND THE CENTRAL AND SOUTHERN ROCKIES, CONSISTENT WITH DYNAMICAL MODEL GUIDANCE  
FROM THE ECMWF ENSEMBLE MEAN SOLUTIONS. BELOW NORMAL HEIGHTS TILT THE ODDS TO  
NEAR TO ABOVE NORMAL PRECIPITATION FOR THE WESTERN CONUS. SURFACE LOW PRESSURE  
OVER THE EASTERN GULF OF ALASKA FAVORS ABOVE NORMAL PRECIPITATION FOR MUCH OF  
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 MODELS AND FORECAST TOOLS.  
 
8-14 DAY OUTLOOK FOR FEB 27 - MAR 05, 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, ALTHOUGH SLIGHTLY LESS AMPLIFIED  
CIRCULATION FEATURES ARE INDICATED AND THE OVERALL LONG WAVE PATTERN IS SHIFTED  
A BIT WESTWARD. ABOVE NORMAL HEIGHTS ARE EXPECTED OVER MOST OF THE EASTERN  
CONUS, MAINLAND ALASKA, AND THE ALEUTIANS, WHILE BELOW NORMAL HEIGHTS ARE  
ANTICIPATED OVER THE WESTERN CONUS, AND THE SOUTHERN ALASKA PANHANDLE.  
 
THE WEEK-2 TEMPERATURE PROBABILITY FORECAST IS VERY SIMILAR TO THE 6-10 DAY  
FORECAST, EXCEPT SLIGHTLY LOWER PROBABILITIES DUE TO THE TYPICALLY INCREASED  
UNCERTAINTY IN THE WEEK-2 PERIOD, AND A GENERAL WESTWARD DISPLACEMENT OF THE  
TEMPERATURE ANOMALY PATTERN DUE TO AN EXPECTED RETROGRESSION OF THE OVERALL  
LONG WAVE HEIGHT PATTERN.  
 
THE BROAD TROUGH FORECAST OVER THE WESTERN CONUS ENHANCES PROBABILITIES OF NEAR  
TO ABOVE NORMAL PRECIPITATION OVER PARTS OF THE HIGH PLAINS AND MISSISSIPPI  
VALLEY AREA. ABOVE NORMAL HEIGHTS TILT THE ODDS TO NEAR TO BELOW NORMAL  
PRECIPITATION FOR PARTS OF THE EASTERN GREAT LAKES, THE OHIO VALLEY, THE MIDDLE  
ATLANTIC, THE NORTHEAST, AND FLORIDA. BELOW NORMAL PRECIPITATION IS ALSO  
FAVORED FOR COLORADO, CONSISTENT WITH DYNAMICAL MODEL GUIDANCE FROM THE ECMWF  
ENSEMBLE MEAN SOLUTIONS. BELOW NORMAL HEIGHTS TILT THE ODDS TO NEAR TO ABOVE  
NORMAL PRECIPITATION FOR PARTS OF THE UTAH, ARIZONA, NEVADA, AND CALIFORNIA.  
SURFACE LOW PRESSURE OVER THE EASTERN GULF OF ALASKA FAVORS ABOVE NORMAL  
PRECIPITATION FOR MUCH OF ALASKA.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 15% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
GOOD AGREEMENT AMONG THE MODELS AND FORECAST TOOLS.  
 
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:  
19590205 - 19890213 - 19570130 - 19550224 - 19660214  
 
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:  
19590205 - 19570202 - 19890201 - 19890212 - 19550224  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 25 - MAR 01, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON B A NRN CALIF B A  
SRN CALIF B A IDAHO B A NEVADA B A  
W MONTANA B A E MONTANA B A WYOMING B N  
UTAH B A ARIZONA B A COLORADO B B  
NEW MEXICO B N N DAKOTA B N S DAKOTA B B  
NEBRASKA B B KANSAS N N OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS N N  
MINNESOTA N N IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A A 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 N  
FL PNHDL A B FL PENIN A B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN N A  
AK S INT B A AK SO COAST B A AK PNHDL B N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 27 - MAR 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 N NEVADA B A  
W MONTANA B N E MONTANA B N WYOMING B N  
UTAH B N ARIZONA B A COLORADO B B  
NEW MEXICO N N N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS A N  
MINNESOTA B A IOWA N A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN N A  
ILLINOIS A A MISSISSIPPI A A MICHIGAN A N  
INDIANA A N OHIO A B KENTUCKY A N  
TENNESSEE A N ALABAMA A N NEW YORK A B  
VERMONT A B NEW HAMP A B MAINE A B  
MASS A B CONN A B RHODE IS A B  
PENN A B NEW JERSEY A B W VIRGINIA A B  
MARYLAND A B DELAWARE A B VIRGINIA A B  
N CAROLINA A N S CAROLINA A N GEORGIA A N  
FL PNHDL A N FL PENIN A B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN N A  
AK S INT B A AK SO COAST B N AK PNHDL B N  
 
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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