104  
FXUS06 KWBC 212008  
PMDMRD  
PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST WED FEB 21 2018  
 
6-10 DAY OUTLOOK FOR FEB 27 - MAR 03, 2018  
 
TODAY'S 00Z GFS ENSEMBLE MEAN SOLUTION FORECASTS A TROUGH 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. TODAY'S MANUAL 500-HPA BLEND INDICATES NEAR TO ABOVE NORMAL HEIGHTS OVER MOST  
OF THE EASTERN CONUS, THE SOUTHERN PLAINS, THE ALEUTIANS, AND MUCH OF MAINLAND ALASKA, AND NEAR TO  
BELOW NORMAL HEIGHTS OVER MUCH OF THE WESTERN CONUS, THE NORTHERN PLAINS, THE SOUTHERN ALASKA  
PANHANDLE, EXTREME NORTHERN MAINLAND ALASKA, AND EASTERN NEW ENGLAND.  
 
PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO INCREASED CHANCES FOR BELOW NORMAL TEMPERATURES  
FOR MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS. A 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 ALASKA FAVORS NEAR TO ABOVE NORMAL TEMPERATURES FOR MOST OF MAINLAND ALASKA  
AS WELL AS THE ALEUTIANS. ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO NEAR TO BELOW NORMAL  
TEMPERATURES FOR 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 EAST-CENTRAL AND SOUTHEASTERN  
CONUS, EXCEPT FOR SOUTHERN FLORIDA WHERE BELOW NORMAL PRECIPITATION IS INDICATED DUE TO THE HIGHLY  
ANOMALOUS SOUTHEAST RIDGE. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE SOUTHERN HIGH  
PLAINS AND WESTERN MONTANA, WHILE ABOVE NORMAL PRECIPITATION IS FORECAST FOR ALASKA, CONSISTENT WITH  
DYNAMICAL MODEL GUIDANCE FROM THE GFS ENSEMBLE MEAN SOLUTIONS. BELOW NORMAL HEIGHTS TILT THE ODDS TO  
NEAR TO ABOVE NORMAL PRECIPITATION FOR THE SOUTHWESTERN CONUS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 100% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8  
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO A RELATIVELY HIGH  
AMPLIFIED FLOW PATTERN ACROSS MUCH OF THE FORECAST DOMAIN.  
 
8-14 DAY OUTLOOK FOR MAR 01 - 07, 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. BELOW NORMAL HEIGHTS ARE EXPECTED OVER MOST  
OF THE WESTERN CONUS AND THE EAST COAST, AND THE SOUTHERN ALASKA PANHANDLE, WHILE NEAR TO ABOVE  
NORMAL HEIGHTS ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
A BROAD TROUGH IN THE WESTERN CONUS LEADS TO INCREASED CHANCES FOR NEAR TO BELOW NORMAL TEMPERATURES  
FOR MUCH OF THE WESTERN AND CENTRAL CONUS. BELOW NORMAL HEIGHTS TILT THE ODDS TO BELOW NORMAL  
TEMPERATURES FOR PARTS OF VIRGINIA AND NORTH CAROLINA. ABOVE NORMAL HEIGHTS LEAD TO ENHANCED CHANCES  
OF NEAR TO ABOVE NORMAL TEMPERATURES FOR PARTS OF THE WESTERN GULF COAST REGION. ANOMALOUS RIDGING  
OVER SOUTHWESTERN ALASKA FAVORS NEAR TO ABOVE NORMAL TEMPERATURES FOR MAINLAND ALASKA AS WELL AS THE  
ALEUTIANS. ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO BELOW NORMAL TEMPERATURES FOR THE ALASKA  
PANHANDLE. THE WEEK-2PRECIPITATION PROBABILITY FORECAST IS VERY SIMILAR TO THE 6-10 DAY FORECAST,  
EXCEPT FOR BELOW NORMAL PRECIPITATION IS FORECAST OVER THE EASTERN GREAT LAKES AND THE NORTHEASTERN  
CONUS.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF 100% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO CONSISTENCY WITH THE  
6-10 DAY PRECIPITATION OUTLOOK 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.  
 
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:  
19510201 - 19520201 - 19530201 - 19540201 - 19550201  
 
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:  
19510131 - 19520131 - 19530131 - 19540131 - 19550131  
 
6 TO 10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 27 - MAR 03, 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 B E MONTANA B N WYOMING B N  
UTAH B A ARIZONA B A COLORADO B N  
NEW MEXICO B N N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS N N OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS N B  
MINNESOTA N 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 N KENTUCKY A A  
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 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 B N  
 
8 TO 14 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 01 - 07, 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 N 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 A OHIO N N KENTUCKY N A  
TENNESSEE N A ALABAMA N A NEW YORK N B  
VERMONT N B NEW HAMP N B MAINE N B  
MASS N B CONN N B RHODE IS N B  
PENN N B NEW JERSEY N B W VIRGINIA N N  
MARYLAND B N DELAWARE B N VIRGINIA B N  
N CAROLINA B N S CAROLINA N A GEORGIA N N  
FL PNHDL N N FL PENIN N 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 N A 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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