405  
FXUS06 KWBC 022002  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST FRI FEBRUARY 02 2018  
 
6-10 DAY OUTLOOK FOR FEB 08 - 12 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED  
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. A DEEP CLOSED-OFF TROUGH IS  
ANTICIPATED NORTH/NORTHEAST OF HUDSON BAY, EXTENDING SOUTHWARD, LEADING TO AN  
AMPLIFIED, BROADLY CYCLONIC FLOW PATTERN ACROSS MOST OF THE CONUS. A RIDGE IS  
PREDICTED OVER THE EAST PACIFIC APPROACHING THE NORTH AMERICAN WEST COAST AND  
EXTENDING NORTH/NORTHWESTWARD TO ALASKA. THERE IS SOME INDICATION THAT  
SHORTWAVE ENERGY WILL START TO UNDERCUT THE WESTERN RIDGE AS A WEAK SOUTHERN  
JET STREAM GETS ESTABLISHED AND TROUGHING DEVELOPS OVER THE SOUTHWEST CONUS. A  
TROUGH IS FORECAST OVER THE ALEUTIANS. THE ENSEMBLE SPAGHETTI CHARTS INDICATE  
LOW TO MODERATE SPREAD OVER THE EASTERN CONUS, AND LARGE SPREAD OVER THE  
WESTERN CONUS AND EASTERN PACIFIC. THE AO INDEX WHICH RECENTLY HAS BEEN  
NEGATIVE IS EXPECTED TO BE NEAR ZERO AT DAY 7, BE NEGATIVE AT DAY 10, AND  
REMAIN NEGATIVE AT DAY 14. THE PNA INDEX WHICH RECENTLY HAS BEEN WEAKLY  
NEGATIVE IS FORECAST TO BECOME WEAKLY POSITIVE AT DAY 7, AND REMAIN POSITIVE  
THROUGH DAY 14. TODAY'S MANUAL 500-HPA BLEND CHART DEPICTS NEAR TO BELOW NORMAL  
HEIGHTS OVER PARTS OF THE ALEUTIANS, WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE  
ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
SURFACE ARCTIC HIGH PRESSURE ENHANCE PROBABILITIES OF NEAR TO BELOW NORMAL  
TEMPERATURES FOR MUCH OF THE CENTRAL AND EASTERN CONUS (EXCEPT FLORIDA).  
ANOMALOUS SOUTHEASTERLY FLOW TILTS THE ODDS TO ABOVE NORMAL TEMPERATURES FOR  
THE ALEUTIANS. NEAR TO ABOVE NORMAL HEIGHTS FAVOR NEAR TO ABOVE NORMAL  
TEMPERATURES FOR THE REMAINDER OF THE FORECAST DOMAIN.  
 
THE BROAD TROUGH FORECAST OVER THE CONUS ENHANCES PROBABILITIES OF ABOVE NORMAL  
PRECIPITATION ALONG THE EAST AND GULF COASTS. UPSLOPE FLOW TILTS THE ODDS TO  
ABOVE NORMAL PRECIPITATION FOR PORTIONS OF THE NORTHERN ROCKIES AND NORTHERN  
HIGH PLAINS. THE TROUGH OVER THE ALEUTIANS FAVORS ABOVE NORMAL PRECIPITATION  
FOR ALASKA. ABOVE NORMAL HEIGHTS AND/OR ANOMALOUS NORTHERLY 500-HPA FLOW TILT  
THE ODDS TO NEAR TO BELOW NORMAL PRECIPITATION FOR THE REMAINDER OF THE CONUS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 5% OF YESTERDAY'S OPERATIONAL 18Z GFS CENTERED ON DAY 7, 10% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF YESTERDAY'S 12Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, AND 10% OF TODAY'S OPERATIONAL 0Z  
ECMWF CENTERED ON DAY 8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS AND FAIR AGREEMENT AMONG THE  
SURFACE TOOLS OFFSET BY INCREASING SPREAD AMONG ENSEMBLE MEMBERS.  
 
8-14 DAY OUTLOOK FOR FEB 10 - 16 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 A SLOW PROGRESSION OF THE  
MAIN CIRCULATION FEATURES IS INDICATED AS HEIGHTS RISE NEAR THE GREAT LAKES.  
THE ENSEMBLE SPAGHETTI CHARTS INDICATE MODERATE SPREAD OVER THE EASTERN CONUS,  
AND LARGE SPREAD OVER THE WESTERN CONUS AND EASTERN PACIFIC. NEAR TO ABOVE  
NORMAL HEIGHTS ARE FORECAST ACROSS MOST OF THE CONUS, SOUTHEASTERN MAINLAND  
ALASKA, AND THE ALASKA PANHANDLE, WHILE NEAR TO BELOW NORMAL HEIGHTS ARE  
ANTICIPATED OVER THE ALEUTIANS AND THE REMAINDER OF MAINLAND ALASKA.  
 
ARCTIC SURFACE HIGH PRESSURE TILTS THE ODDS TO NEAR TO BELOW NORMAL  
TEMPERATURES FOR THE EASTERN THIRD OF THE CONUS AND ALONG THE GULF COAST. ABOVE  
NORMAL HEIGHTS FAVOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE WESTERN  
TWO-THIRDS OF THE CONUS AND THE ALASKA PANHANDLE. ANOMALOUS SOUTHERLY FLOW  
ENHANCES PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR THE ALEUTIANS AND  
SOUTHERN AND CENTRAL MAINLAND ALASKA.  
 
ABOVE NORMAL HEIGHTS, ANOMALOUS NORTH/NORTHWESTERLY FLOW, AND SPRAWLING SURFACE  
HIGH PRESSURE FAVOR NEAR TO BELOW NORMAL PRECIPITATION FOR MOST OF THE NORTHERN  
AND CENTRAL CONUS. THE DEVELOPMENT OF A SOUTHERN JET STREAM ENHANCES  
PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR SOUTHERN TEXAS AND PARTS OF THE  
SOUTHEAST CONUS. THE TROUGH OVER THE ALEUTIANS TILTS THE ODDS TO ABOVE NORMAL  
PRECIPITATION FOR PARTS OF THE ALEUTIANS, SOUTHERN AND CENTRAL MAINLAND ALASKA,  
AND THE ALASKA PANHANDLE.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 15% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 35% OF YESTERDAY'S  
12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO  
FAIR AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFF-SET BY MODERATE TO LARGE  
SPREAD AMONG ENSEMBLE MEMBERS OVER MUCH OF THE FORECAST DOMAIN.  
 
FORECASTER: RANDY S  
 
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:  
19820211 - 20050116 - 19590119 - 19970126 - 19950215  
 
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:  
19950215 - 19590118 - 20050115 - 19820210 - 19970126  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 08 - 12 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 A WYOMING A B  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA N A S DAKOTA N N  
NEBRASKA A B KANSAS N B OKLAHOMA B B  
N TEXAS B N S TEXAS B A W TEXAS N N  
MINNESOTA N N IOWA N B MISSOURI B B  
ARKANSAS B B LOUISIANA B A WISCONSIN B N  
ILLINOIS B B MISSISSIPPI B N MICHIGAN B N  
INDIANA B B OHIO B N KENTUCKY B B  
TENNESSEE B N ALABAMA B A NEW YORK B N  
VERMONT B A NEW HAMP B A MAINE B A  
MASS B A CONN B A RHODE IS B A  
PENN B N NEW JERSEY B A W VIRGINIA B N  
MARYLAND B A DELAWARE B A VIRGINIA B A  
N CAROLINA B A S CAROLINA B A GEORGIA B A  
FL PNHDL N A FL PENIN A A 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 10 - 16 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 A B WYOMING A B  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA A B S DAKOTA A B  
NEBRASKA A B KANSAS A B OKLAHOMA A B  
N TEXAS N N S TEXAS B A W TEXAS A A  
MINNESOTA A B IOWA A B MISSOURI A B  
ARKANSAS N B LOUISIANA B N WISCONSIN A B  
ILLINOIS A B MISSISSIPPI B B MICHIGAN N B  
INDIANA N B OHIO N B KENTUCKY N B  
TENNESSEE B B ALABAMA B N NEW YORK B B  
VERMONT B B NEW HAMP B B MAINE B B  
MASS B B CONN B B RHODE IS B B  
PENN B B NEW JERSEY B B W VIRGINIA B B  
MARYLAND B B DELAWARE B B VIRGINIA B B  
N CAROLINA B N S CAROLINA B A GEORGIA B N  
FL PNHDL B A FL PENIN B A AK N SLOPE N N  
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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