511  
FXUS06 KWBC 122003  
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 12 2018  
 
6-10 DAY OUTLOOK FOR FEB 18 - 22 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN VERY GOOD AGREEMENT ON THE EXPECTED  
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. ALL OF TODAY'S MODEL SOLUTIONS  
FORECAST AN AMPLIFIED RIDGE OVER MAINLAND ALASKA, A TROUGH OVER MUCH OF CANADA  
INTO THE WESTERN HALF OF THE CONUS, AND A RIDGE OVER MUCH OF THE EASTERN U.S.  
THE FORECAST PATTERN IS VERY HIGH AMPLITUDE, INCREASING CONFIDENCE IN THE  
FORECAST AND RESULTING IN FAIRLY LARGE FORECAST PROBABILITIES. IN ADDITION  
THERE IS EXCELLENT AGREEMENT BETWEEN THE TOOLS AND BETWEEN TODAY'S GFS, ECMWF,  
AND CANADIAN ENSEMBLE MEANS. TODAY'S MANUAL 500-HPA BLEND FAVORS LARGELY  
POSITIVE HEIGHT ANOMALIES OVER ALL OF ALASKA, NEGATIVE HEIGHT ANOMALIES OVER  
THE WESTERN HALF OF THE CONUS, AND POSITIVE HEIGHT ANOMALIES OVER THE EASTERN  
HALF OF THE CONUS.  
 
HIGHLY ANOMALOUS RIDGING OVER ALASKA STRONGLY FAVORS ABOVE NORMAL TEMPERATURES  
FOR MOST OF ALASKA. PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO  
INCREASED CHANCES FOR BELOW NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND  
NORTH-CENTRAL CONUS, ESPECIALLY IN THE NORTHERN PLAINS AND ROCKIES WHERE  
NEGATIVE HEIGHT ANOMALIES ARE THE LARGEST. A STRONG RIDGE FORECAST OVER THE  
EASTERN U.S. LEADS TO ENHANCED CHANCES OF ABOVE NORMAL TEMPERATURES.  
 
THE STRONG RIDGE FORECAST OVER ALASKA IS EXPECTED TO PUSH THE TYPICAL STORM  
TRACK FARTHER NORTH, LARGELY FAVORING ABOVE NORMAL PRECIPITATION FOR MUCH OF  
MAINLAND ALASKA, EXCEPT FOR THE SOUTHERN COAST AND ALASKA PANHANDLE WHERE A  
MORE NORTHERLY STORM TRACK WOULD FAVOR DRIER CONDITIONS. NEAR TO BELOW NORMAL  
PRECIPITATION IS FAVORED FOR THE WEST COAST, WEST OF THE TROUGH AXIS. A COUPLE  
OF STORM SYSTEMS ARE FORECAST TO DROP SOUTH INTO THE CONUS, WITHIN THE TROUGH,  
AND INCREASE THE LIKELIHOOD OF ABOVE NORMAL PRECIPITATION FOR PARTS OF THE  
GREAT BASIN, ROCKIES AND NORTHERN PLAINS. A STATIONARY FRONT IS EXPECTED TO  
SETUP ACROSS TEXAS, THE MIDDLE MISSISSIPPI VALLEY, OHIO VALLEY AND NORTHEAST,  
FAVORING INCREASED STORM SYSTEM ACTIVITY AND ABOVE NORMAL PRECIPITATION.  
BENEATH THE HIGHLY ANOMALOUS SOUTHEAST RIDGE, BELOW NORMAL PRECIPITATION IS  
FAVORED FOR PARTS OF THE GULF COAST, MID-ATLANTIC COAST, AND FLORIDA.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 60% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 40% OF TODAY'S OPERATIONAL 0Z  
ECMWF CENTERED ON DAY 8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: WELL ABOVE AVERAGE, 5 OUT OF 5,  
DUE TO VERY GOOD AGREEMENT AMONG THE MODELS AND TOOLS.  
 
8-14 DAY OUTLOOK FOR FEB 20 - 26 2018  
 
BY THE WEEK-2 PERIOD, THE LARGE-SCALE PATTERN OVER THE FORECAST DOMAIN IS  
EXPECTED TO BE SHIFTED SLIGHTLY WEST, AND SLIGHTLY LESS AMPLIFIED, BUT REMAIN  
LARGELY UNCHANGED. THE HEIGHT ANOMALIES DEPICTED IN THE MANUAL 500-HPA BLEND  
ARE RELATIVELY LARGE FOR THE WEEK-2 PERIOD, SUGGESTING VERY GOOD MODEL  
AGREEMENT AND CERTAINTY. THE WEEK-2 TEMPERATURE PROBABILITY FORECAST IS VERY  
SIMILAR TO THE 6-10 DAY FORECAST, EXCEPT IN THE EASTERN U.S. PROBABILITIES OF  
ABOVE NORMAL TEMPERATURES ARE EVEN HIGH, DUE TO THE FACT THAT THE RIDGE IS  
PREDICTED TO MIGRATE SLIGHTLY WESTWARD, WITH THE LARGEST POSITIVE HEIGHT  
ANOMALIES BECOMING CENTERED ALONG THE EAST COAST. THE WEEK-2 PRECIPITATION  
PROBABILITY FORECAST IS ALSO VERY SIMILAR TO THE 6-10 DAY FORECAST, EXCEPT  
PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE INCREASED OVER THE MIDDLE  
MISSISSIPPI VALLEY DUE TO VERY GOOD AGREEMENT ON PERSISTENT STORM SYSTEM  
ACTIVITY ALONG THE STATIONARY FRONT DURING THE WEEK-2 PERIOD.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S  
OPERATIONAL 6Z GFS CENTERED ON DAY 11, AND 60% OF TODAY'S 0Z EUROPEAN ENSEMBLE  
MEAN CENTERED ON DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: WELL ABOVE AVERAGE, 5 OUT OF 5,  
DUE TO VERY GOOD AGREEMENT AMONG THE MODELS AND TOOLS.  
 
FORECASTER: MIKE C  
 
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:  
19820131 - 19890213 - 19820205 - 19570124 - 19890205  
 
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:  
19820202 - 19570124 - 19590201 - 19890213 - 19750124  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 18 - 22 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B B  
SRN CALIF B B IDAHO B A NEVADA B B  
W MONTANA B A E MONTANA B A WYOMING B A  
UTAH B A ARIZONA B N COLORADO B A  
NEW MEXICO A N N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B A OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS A A  
MINNESOTA B A IOWA B A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN N 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 N 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 A A AK SO COAST N B AK PNHDL B B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 20 - 26 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B B NRN CALIF B B  
SRN CALIF B B IDAHO B N NEVADA B B  
W MONTANA B A E MONTANA B A WYOMING B A  
UTAH B N ARIZONA B N COLORADO B A  
NEW MEXICO B N N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B A OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS A A  
MINNESOTA B A IOWA B A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN N 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 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 A A AK SO COAST N N AK PNHDL B 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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