035  
FXUS06 KWBC 312002  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST WED JANUARY 31 2018  
 
6-10 DAY OUTLOOK FOR FEB 06 - 10 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 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 WESTERN ALASKA. THE ENSEMBLE SPAGHETTI CHARTS  
INDICATE MOSTLY LOW TO MODERATE SPREAD OVER THE FORECAST DOMAIN. THE AO INDEX  
WHICH RECENTLY HAS TRENDED FROM WEAKLY POSITIVE TO NEAR ZERO IS EXPECTED TO  
REMAIN NEAR ZERO AT DAY 7, BE WEAKLY 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  
THE NORTH-CENTRAL CONUS AND THE ALEUTIANS, WHILE NEAR TO ABOVE NORMAL HEIGHTS  
ARE ANTICIPATED OVER THE REMAINDER OF THE FORECAST DOMAIN.  
 
NEAR TO BELOW NORMAL HEIGHTS ENHANCE PROBABILITIES OF NEAR TO BELOW NORMAL  
TEMPERATURES FOR MUCH OF THE NORTH-CENTRAL AND INTERIOR NORTHEASTERN CONUS.  
ANOMALOUS SOUTHEASTERLY FLOW TILTS THE ODDS TO ABOVE NORMAL TEMPERATURES FOR  
THE ALEUTIANS. NEAR TO ABOVE NORMAL HEIGHTS FAVORS NEAR TO ABOVE NORMAL  
TEMPERATURES FOR THE REMAINDER OF THE FORECAST DOMAIN.  
 
THE BROAD TROUGH FORECAST OVER THE CONUS ENHANCES PROBABILITIES FOR ABOVE  
NORMAL PRECIPITATION FOR MUCH OF THE NORTHEASTERN AND NORTH-CENTRAL CONUS.  
UPSLOPE FLOW TILTS THE ODDS TO ABOVE NORMAL PRECIPITATION FOR PARTS OF THE  
NORTHERN ROCKIES AND NORTHERN PLAINS. ANOMALOUS SOUTHEASTERLY FLOW FAVORS ABOVE  
NORMAL PRECIPITATION FOR THE ENTIRE SOUTH COAST OF ALASKA. ABOVE NORMAL HEIGHTS  
AND/OR ANOMALOUS NORTHERLY 500-HPA FLOW FAVORS NEAR TO BELOW NORMAL  
PRECIPITATION FOR THE REMAINDER OF THE CONUS AND NORTHERN MAINLAND ALASKA.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% 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 6Z GFS CENTERED ON DAY 8, 30% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 20% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS AND AMONG THE SURFACE TOOLS.  
 
8-14 DAY OUTLOOK FOR FEB 08 - 14 2018  
 
THE MEAN 500-HPA PATTERN EXPECTED FOR THE WEEK-2 PERIOD IS SIMILAR TO THAT  
DEPICTED FOR THE 6 TO 10 DAY TIME FRAME. THE ECMWF BASED ENSEMBLE MEAN  
SOLUTIONS ARE A BIT MORE PROGRESSIVE WITH THE MAIN CIRCULATION FEATURES. GIVEN  
THE USUAL MODEL BIAS OF CLOSED-OFF TROUGHS LIFTING OUT FASTER THEN OBSERVED,  
THE SLOWER GFS SOLUTIONS ARE GIVEN HIGHER WEIGHTS IN THE BLENDED HEIGHT  
FORECAST CHART. THE ENSEMBLE SPAGHETTI CHARTS INDICATE LOW TO MODERATE SPREAD  
OVER THE EASTERN CONUS, AND MODERATE TO LARGE SPREAD OVER THE WESTERN CONUS AND  
EASTERN PACIFIC.  
 
NEAR TO BELOW NORMAL HEIGHTS AND/OR ARCTIC SURFACE HIGH PRESSURE TILT THE ODDS  
TO NEAR TO BELOW NORMAL TEMPERATURES FOR PARTS OF THE CENTRAL AND EASTERN CONUS.  
ABOVE NORMAL HEIGHTS FAVOR ABOVE NORMAL TEMPERATURES FOR THE WESTERN THIRD OF  
THE CONUS, THE ALASKA PANHANDLE, AND PARTS OF SOUTHERN AND CENTRAL MAINLAND  
ALASKA. ANOMALOUS SOUTHEASTERLY FLOW ENHANCES PROBABILITIES FOR ABOVE NORMAL  
TEMPERATURES FOR THE ALEUTIANS.  
 
UPSLOPE FLOW TILT THE ODDS TO ABOVE NORMAL PRECIPITATION FOR PARTS OF THE  
NORTHERN ROCKIES AND NORTHERN PLAINS. ABOVE NORMAL HEIGHTS AND ANOMALOUS  
NORTH/NORTHWESTERLY FLOW STRONGLY FAVOR BELOW NORMAL PRECIPITATION FOR PARTS OF  
THE WESTERN CONUS. SURFACE ARCTIC HIGH PRESSURE ENHANCES PROBABILITIES FOR NEAR  
TO BELOW NORMAL PRECIPITATION FOR MUCH OF THE CENTRAL AND EASTERN CONUS.  
ANOMALOUS SOUTHERLY (SOUTHEASTERLY) FLOW TILT THE ODDS TO ABOVE NORMAL  
PRECIPITATION FOR PARTS OF MAINE (THE ALEUTIANS AND SOUTHWESTERN MAINLAND  
ALASKA). ABOVE NORMAL HEIGHTS FAVOR BELOW NORMAL PRECIPITATION FOR NORTHERN  
MAINLAND ALASKA.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 25% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 25% OF  
YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, AND 10% OF TODAY'S  
0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
FAIR AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFF-SET BY MODERATE TO LARGE  
SPREAD AMONG ENSEMBLE MEMBERS OVER PARTS 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:  
19530126 - 19510123 - 19540126 - 19820211 - 19560114  
 
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:  
19510123 - 19530126 - 19540125 - 19590115 - 19560114  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 06 - 10 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 N E MONTANA B A WYOMING A N  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA B A S DAKOTA B A  
NEBRASKA B N KANSAS N B OKLAHOMA N B  
N TEXAS N N S TEXAS A N W TEXAS A B  
MINNESOTA B A IOWA B A MISSOURI B N  
ARKANSAS N N LOUISIANA N N WISCONSIN B A  
ILLINOIS B A MISSISSIPPI N N MICHIGAN B A  
INDIANA B A OHIO B A KENTUCKY B A  
TENNESSEE N A ALABAMA N A NEW YORK B A  
VERMONT B A NEW HAMP B A MAINE B A  
MASS N A CONN N A RHODE IS N A  
PENN B A NEW JERSEY N A W VIRGINIA B A  
MARYLAND N A DELAWARE N A VIRGINIA N A  
N CAROLINA N A S CAROLINA N A GEORGIA N A  
FL PNHDL N N FL PENIN N N AK N SLOPE N B  
AK ALEUTIAN A A AK WESTERN N A AK INT BSN N B  
AK S INT A A AK SO COAST A A AK PNHDL A A  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 08 - 14 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 B A S DAKOTA B N  
NEBRASKA B B KANSAS B B OKLAHOMA B B  
N TEXAS N B S TEXAS N N W TEXAS N N  
MINNESOTA B N IOWA B B MISSOURI B B  
ARKANSAS B B LOUISIANA N B WISCONSIN B N  
ILLINOIS B B MISSISSIPPI B B MICHIGAN B B  
INDIANA B B OHIO B B KENTUCKY B B  
TENNESSEE B B ALABAMA B B NEW YORK B N  
VERMONT B N NEW HAMP B N MAINE B A  
MASS B N CONN B N RHODE IS B N  
PENN B B NEW JERSEY B B W VIRGINIA B B  
MARYLAND B B DELAWARE B B VIRGINIA B B  
N CAROLINA B B S CAROLINA B B GEORGIA B B  
FL PNHDL N B FL PENIN N B AK N SLOPE N B  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A N  
AK S INT A N 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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