133  
FXUS06 KWBC 072001  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST WED FEBRUARY 07 2018  
 
6-10 DAY OUTLOOK FOR FEB 13 - 17 2018  
 
THE ENSEMBLE MEANS AND THEIR DETERMINISTIC MODEL RUNS ARE IN GOOD AGREEMENT  
THAT A STRONG SUBTROPICAL RIDGE (500-HPA HEIGHTS ABOVE 588 DM) DEVELOPS OVER  
THE GULF OF MEXICO, FLORIDA, AND THE SOUTHWEST ATLANTIC BY DAY 6. THE 6Z GFS  
AND 0Z ECMWF ENSEMBLE MEANS FEATURE A SLIGHTLY MORE AMPLIFIED 500-HPA RIDGE  
OVER THE NORTHEAST PACIFIC THAN THE 0Z CANADIAN ENSEMBLE MEAN. ELSEWHERE, MODEL  
SOLUTIONS ARE IN GOOD AGREEMENT WITH AN UPPER-LEVEL TROUGH EXTENDING FROM  
HUDSON BAY SOUTHWEST TO THE WEST-CENTRAL CONUS.  
 
THE STRENGTHENING SUBTROPICAL RIDGE FAVORS ABOVE-NORMAL TEMPERATURES ACROSS THE  
EASTERN THIRD OF THE CONUS. THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL  
TEMPERATURES ARE FORECAST ACROSS THE SOUTHEAST WHERE MINIMUM TEMPERATURES ARE  
LIKELY TO AVERAGE 15 TO 25 DEGREES F ABOVE NORMAL ON DAYS 6 AND 7. ABOVE-NORMAL  
TEMPERATURES ARE ALSO FAVORED ACROSS THE WESTERN U.S. DUE TO RIDGING ALOFT, BUT  
PROBABILITIES ARE TEMPERED SINCE THE STATISTICAL TOOLS OFFER A COLDER SOLUTION.  
THE LOWEST CONFIDENCE IN THE TEMPERATURE OUTLOOK EXISTS ACROSS THE  
NORTH-CENTRAL U.S. WHERE TEMPERATURES ARE EXPECTED TO BE VARIABLE DURING THE  
5-DAY PERIOD AND TEMPERATURE TOOLS DISAGREE. THE WARMER ECMWF SOLUTION IS  
PREFERRED ACROSS THIS REGION BASED ON THE MEAN SEA LEVEL PRESSURE FIELDS WHICH  
DEPICT ONLY MODEST SURFACE HIGH PRESSURE EXTENDING SOUTH FROM CANADA. A SLIGHT  
TILT IN THE ODDS FOR BELOW-NORMAL TEMPERATURES IS FORECAST FOR THE NORTHERN  
HIGH PLAINS WHERE ARCTIC SURFACE HIGH PRESSURE IS MOST LIKELY TO EXTEND SOUTH  
INTO THE CONUS.  
 
THE UPPER-LEVEL RIDGE ANCHORED OFFSHORE OF THE WEST COAST STRONGLY FAVORS  
BELOW-NORMAL PRECIPITATION ACROSS THE WESTERN CONUS WITH THE HIGHEST  
PROBABILITIES ACROSS NORTHERN CALIFORNIA WHERE THE GEFS MEAN INDICATES NO  
PRECIPITATION DURING THE 5-DAY PERIOD. SOUTHWEST FLOW ALOFT AND RETURN FLOW  
FROM THE GULF OF MEXICO ENHANCE ODDS FOR ABOVE-NORMAL PRECIPITATION ACROSS THE  
EASTERN THIRD OF THE CONUS. A SHORTWAVE TROUGH IN THE SOUTHERN STREAM TILTS THE  
ODDS TO ABOVE-NORMAL PRECIPITATION ACROSS THE BIG BEND REGION OF TEXAS. SINCE  
GFS AND ECMWF ENSEMBLE MEMBERS HAVE A CLOSED 500-HPA LOW DEVELOPING NEAR  
SOUTHERN CALIFORNIA DURING THIS PERIOD, PROBABILITIES FOR BELOW-NORMAL  
PRECIPITATION ARE REDUCED ACROSS SOUTHERN CALIFORNIA AND THE DESERT SOUTHWEST.  
 
AN UPPER-LEVEL TROUGH OVER THE BERING SEA COUPLED WITH SOUTHWEST FLOW AT THE  
SURFACE INCREASE CHANCES FOR ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL  
PRECIPITATION THROUGHOUT ALASKA.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 6Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, AND 60% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD  
AGREEMENT AMONG PRECIPITATION TOOLS OFFSET BY POOR AGREEMENT AMONG TEMPERATURE  
TOOLS.  
 
8-14 DAY OUTLOOK FOR FEB 15 - 21 2018  
 
THE GFS AND ECMWF ENSEMBLE MEANS MAINTAIN THE UPPER-LEVEL RIDGE OVER THE  
NORTHEAST PACIFIC AND INDICATE THAT IT AMPLIFIES NORTH TO THE HIGHER LATITUDES  
OF ALASKA DURING WEEK-2. THESE ENSEMBLE MEANS FEATURE A DECREASE IN 500-HPA  
HEIGHTS ACROSS THE EASTERN THIRD OF THE CONUS COMPARED TO YESTERDAY'S  
SOLUTIONS. THESE LOWER 500-HPA HEIGHTS ARE ASSOCIATED WITH A WEAKENING OF THE  
SUBTROPICAL RIDGE OVER THE GULF OF MEXICO AND AN EASTWARD SHIFT OF THE  
UPPER-LEVEL TROUGH. THEREFORE, NEAR TO BELOW-NORMAL TEMPERATURES ARE FAVORED  
FOR PARTS OF THE MISSISSIPPI VALLEY, WHILE THE COVERAGE AND PROBABILITIES FOR  
ABOVE-NORMAL TEMPERATURES ARE REDUCED ACROSS THE EASTERN CONUS COMPARED TO THE  
6-10 DAY PERIOD. THE UPPER-LEVEL RIDGE ALOFT CONTINUES TO FAVOR ABOVE-NORMAL  
TEMPERATURES ACROSS THE WESTERN CONUS. A LACK OF SNOW COVER FOR THIS TIME OF  
YEAR ACROSS CALIFORNIA AND THE GREAT BASIN ALSO FAVORS ABOVE-NORMAL  
TEMPERATURES ACROSS THESE AREAS.  
 
THE HIGHEST CONFIDENCE IN THE PRECIPITATION OUTLOOK EXISTS ACROSS THE WESTERN  
CONUS WHERE THE RIDGE UPSTREAM OVER THE NORTHEAST PACIFIC STRONGLY FAVORS  
BELOW-NORMAL PRECIPITATION FOR THIS REGION. PRECIPITATION SIGNALS ARE WEAK  
AMONG THE TOOLS EAST OF THE ROCKIES. AN EXPECTED TEMPERATURE GRADIENT FAVORS  
NEAR TO ABOVE-NORMAL PRECIPITATION FROM THE GREAT LAKES AND NEW ENGLAND  
SOUTHWEST TO TEXAS. ENHANCED ODDS FOR BELOW-NORMAL PRECIPITATION ARE FORECAST  
FOR THE SOUTHEAST SINCE THE LONGWAVE PATTERN FAVORS A STORM TRACK TO THE  
NORTHWEST OF THIS REGION.  
 
DUE TO THE PERSISTENT UPPER-LEVEL TROUGH OVER THE BERING SEA, INCREASED CHANCES  
FOR ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL PRECIPITATION ARE FORECAST TO  
CONTINUE ACROSS ALASKA THROUGH THE WEEK-2 PERIOD.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 6Z GFS  
ENSEMBLE MEAN 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: BELOW AVERAGE, 2 OUT OF 5, DUE TO  
POOR MODEL CONTINUITY AND POOR AGREEMENT AMONG TEMPERATURE TOOLS.  
 
FORECASTER: BRAD PUGH  
 
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 - 20030209 - 19570125 - 19910128  
 
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:  
19630119 - 19840119 - 19570124 - 19910127 - 19630124  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 13 - 17 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A B OREGON A B NRN CALIF A B  
SRN CALIF A B IDAHO A B NEVADA A B  
W MONTANA N B E MONTANA B B WYOMING N B  
UTAH A B ARIZONA A B COLORADO N B  
NEW MEXICO A B N DAKOTA N N S DAKOTA N B  
NEBRASKA N B KANSAS N B OKLAHOMA N B  
N TEXAS N N S TEXAS N N W TEXAS N B  
MINNESOTA N N IOWA N B MISSOURI N B  
ARKANSAS A A LOUISIANA A A WISCONSIN N B  
ILLINOIS N B MISSISSIPPI A A MICHIGAN N N  
INDIANA A N 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 A FL PENIN A N 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 A A  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 15 - 21 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A B OREGON A B NRN CALIF A B  
SRN CALIF A B IDAHO A B NEVADA A B  
W MONTANA A B E MONTANA N B WYOMING A B  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA N B S DAKOTA N B  
NEBRASKA N B KANSAS A B OKLAHOMA A B  
N TEXAS N N S TEXAS N N W TEXAS A A  
MINNESOTA N N IOWA N B MISSOURI N N  
ARKANSAS N N LOUISIANA N B WISCONSIN B N  
ILLINOIS N N MISSISSIPPI A B MICHIGAN B A  
INDIANA N A OHIO N A KENTUCKY N A  
TENNESSEE A N ALABAMA A B NEW YORK N A  
VERMONT N A NEW HAMP A A MAINE N A  
MASS A A CONN A A RHODE IS A A  
PENN A A NEW JERSEY A N W VIRGINIA A N  
MARYLAND A N DELAWARE A N VIRGINIA A N  
N CAROLINA A B 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 A A AK SO COAST A A AK PNHDL A 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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