554  
FXUS06 KWBC 202208  
PMDMRD  
PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST TUE FEB 20 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  
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 MAINLAND  
ALASKA, AND NEAR TO BELOW NORMAL HEIGHTS OVER MUCH OF THE WESTERN CONUS, THE  
NORTHERN PLAINS, AND SOUTHERN ALASKA PANHANDLE.  
 
PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO INCREASED CHANCES OF 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 HIGH 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 COLORADO, NEW MEXICO,  
AND EASTERN TEXAS, 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 MOST 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 LESS AMPLIFIED  
CIRCULATION FEATURES ARE INDICATED AND THE OVERALL LONG WAVE PATTERN IS  
SHIFTED A BIT WESTWARD. BELOW NORMAL HEIGHTS ARE EXPECTED OVER MOST OF THE  
WESTERN CONUS AND THE EAST COAST AND SOUTHERN ALASKA PANHANDLE, WHILE ABOVE  
NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
A DEEP TROUGH IN THE WESTERN CONUS LEADS TO INCREASED CHANCES OF NEAR TO BELOW  
NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND CENTRAL CONUS. A RIDGE  
FORECAST OVER THE SOUTHEASTERN U.S. LEADS TO ENHANCED CHANCES OF NEAR TO ABOVE  
NORMAL TEMPERATURES FOR THE EASTERN CONUS. 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 BROAD TROUGH FORECAST OVER THE WESTERN CONUS ENHANCES PROBABILITIES OF  
NEAR TO ABOVE NORMAL PRECIPITATION OVER PARTS OF THE HIGH PLAINS AND  
MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, AND THE SOUTHEAST. 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 PARTS OF WESTERN  
MONTANA, COLORADO, NEW MEXICO AND WESTERN TEXAS, 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: 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  
 
ABOUT AVERAGE, 3 OUT OF 5, DUE TO FAIRLY GOOD MODEL AGREEMENT, WITH SOME  
DISAGREEMENT AMONG THE TEMPERATURE 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.  
 
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:  
19890213 - 19550223 - 19570131 - 19590205 - 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:  
19890201 - 19550224 - 19570131 - 19590206 - 20010212  
 
6 TO 10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 26 - MAR 02, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B A 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 N  
NEW MEXICO B B N DAKOTA B A S DAKOTA B A  
NEBRASKA B N KANSAS N N OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS N N  
MINNESOTA N A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN A N  
ILLINOIS A N MISSISSIPPI A A MICHIGAN A N  
INDIANA A N OHIO A N KENTUCKY A N  
TENNESSEE A A ALABAMA A A 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 N NEW JERSEY A N W VIRGINIA A N  
MARYLAND A N DELAWARE A N VIRGINIA A N  
N CAROLINA A A S CAROLINA A A GEORGIA A A  
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 B A AK PNHDL B B  
 
 
8 TO 14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 28 - MAR 06, 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 A ARIZONA B A COLORADO B N  
NEW MEXICO B B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B A OKLAHOMA N A  
N TEXAS N A S TEXAS A A W TEXAS N N  
MINNESOTA B A IOWA B A MISSOURI N A  
ARKANSAS N A LOUISIANA A A WISCONSIN N A  
ILLINOIS N A MISSISSIPPI A A MICHIGAN N N  
INDIANA N N OHIO N N KENTUCKY N N  
TENNESSEE N A ALABAMA A A NEW YORK N B  
VERMONT A B NEW HAMP A B MAINE A B  
MASS N B CONN N B RHODE IS N B  
PENN N B NEW JERSEY N B W VIRGINIA N N  
MARYLAND N B DELAWARE N B VIRGINIA N N  
N CAROLINA N N S CAROLINA N 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 A A  
AK S INT B N AK SO COAST B 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 - ON AFOS AS  
NFDPMDMRD.  
 

 
 
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