150  
FXUS06 KWBC 061902  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EDT MON MAY 06 2024  
 
6-10 DAY OUTLOOK FOR MAY 12 - 16 2024  
 
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED AMPLIFIED  
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING  
THE 6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE  
ENSEMBLE MEANS FROM THE GEFS, ECENS, AND CANADIAN MODELS DUE TO RECENT MODEL  
SKILL. THE RESULTANT MANUAL BLEND FEATURES A 500-HPA TROUGH AND NEGATIVE  
500-HPA HEIGHT ANOMALIES ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS). A RIDGE  
AND ASSOCIATED POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST OVER THE  
NORTHWESTERN CONUS, WHILE A WEAK TROUGH IS FORECAST OVER THE SOUTHWESTERN  
CONUS. A TROUGH IS FORECAST OVER ALASKA. WEAK TROUGHING WITH NEGATIVE 500-HPA  
HEIGHT ANOMALIES ARE FAVORED FOR HAWAII.  
 
MID-LEVEL RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES ACROSS THE WESTERN  
CONUS BRING ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER MUCH OF THE  
WESTERN CONUS EXTENDING EASTWARD THROUGH THE HIGH PLAINS, THE UPPER AND MIDDLE  
MISSISSIPPI VALLEY, AND INTO THE UPPER GREAT LAKES REGION. THE STRONGEST  
CHANCES ARE FORECAST OVER PARTS OF OREGON, CALIFORNIA, NEVADA, AND UTAH WITH  
PROBABILITIES EXCEEDING 70% IN THIS REGION. ANOMALOUS MID-LEVEL TROUGHING  
FAVORS NEAR- TO BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE SOUTHERN PLAINS  
AND THE EASTERN CONUS, EXCEPT FOR MAINE AND SOUTHERN FLORIDA WHERE ABOVE-NORMAL  
TEMPERATURES ARE INDICATED. IN ALASKA, WEAKLY BELOW-NORMAL 500-HPA HEIGHT  
ANOMALIES LEAD TO CHANCES FOR BELOW-NORMAL TEMPERATURES ACROSS THE STATE. IN  
HAWAII, ABOVE-NORMAL TEMPERATURES ARE FORECAST CONSISTENT WITH THE  
CONSOLIDATION OF TOOLS.  
 
IN THE PACIFIC NORTHWEST, BELOW-NORMAL PRECIPITATION IS LIKELY BENEATH THE  
POSITIVE 500-HPA HEIGHT ANOMALIES. THE BELOW-NORMAL CHANCES OVERSPREAD THE  
NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS. ALONG THE SOUTHERN AND EASTERN  
EDGE OF THE TROUGH ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED AS A SURFACE  
FRONTAL BOUNDARY IS LIKELY TO BECOME ESTABLISHED THAT MAY HELP TO FOCUS  
PRECIPITATION ALONG THE EAST COAST AND GULF COAST. AREAS OF SURFACE  
LOW-PRESSURE MAY DEVELOP IN THE SOUTHERN ROCKIES AND A WEAK TROUGH PREDICTED  
OVER THE SOUTHWEST THAT MAY BRING PRECIPITATION TO THE REGION. IN ALASKA,  
ABOVE-NORMAL PRECIPITATION IS FORECAST OVER MUCH OF ALASKA AS TROUGHING MAY  
BRING ONSHORE FLOW. IN HAWAII, ABOVE-NORMAL PRECIPITATION IS FAVORED DUE TO A  
WEAK TROUGH OVER THE REGION.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 6Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 8, AND 30% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY  
8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
GOOD AGREEMENT AMONG MODEL SOLUTIONS AND FORECAST TEMPERATURE AND PRECIPITATION  
TOOLS.  
 
8-14 DAY OUTLOOK FOR MAY 14 - 20 2024  
 
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD MAINTAIN A FAIRLY PERSISTENT  
AND LESS AMPLIFIED 500-HPA CIRCULATION PATTERN RELATIVE TO THE 6-10 DAY PERIOD  
ACROSS NORTH AMERICA AND THE SURROUNDING REGIONS. DURING WEEK-2, A RIDGE IS  
FORECAST OVER THE WESTERN CONUS. A WEAK TROUGH WITH NEGATIVE ANOMALIES IS  
FORECAST OVER THE EASTERN CONUS. ANOTHER WEAK TROUGH IS PREDICTED OVER ALASKA,  
WHILE RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS ARE FORECAST OVER THE ALEUTIANS.  
A WEAK TROUGH WITH SLIGHTLY BELOW-NORMAL 500-HPA HEIGHTS CONTINUED TO BE  
PREDICTED OVER HAWAII.  
 
A WEAK MID-LEVEL TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES SUPPORTS  
NEAR-NORMAL TEMPERATURE FOR MUCH OF THE EASTERN CONUS, EXCLUDING PORTIONS OF  
THE NORTHEAST AND FLORIDA PENINSULA WHERE ABOVE-NORMAL TEMPERATURES ARE  
INDICATED. ELEVATED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE FORECAST  
OVER MUCH OF THE CENTRAL AND WESTERN CONUS DUE TO THE FORECAST RIDGING AND  
ABOVE-NORMAL 500-HPA HEIGHTS. IN ALASKA, BELOW-NORMAL TEMPERATURES ARE SLIGHTLY  
FAVORED WITH CONTINUED WEAK TROUGHING IMPACTING THE STATE. IN HAWAII, SLIGHTLY  
ABOVE-NORMAL TEMPERATURES ARE FORECAST CONSISTENT WITH THE CONSOLIDATION OF  
TOOLS.  
 
BELOW-NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE PACIFIC NORTHWEST AND  
THE NORTHERN ROCKIES WITH RIDGING OVER THE REGION. NEAR- TO ABOVE-NORMAL  
PRECIPITATION IS FORECAST OVER THE REMAINDER OF THE CONUS DUE TO SOUTHERLY  
RETURN FLOW ASSOCIATED WITH MEAN SURFACE HIGH PRESSURE OVER THE SOUTHEAST AND  
THE MID-LEVEL TROUGH EXPECTED TO LINGER IN THE REGION THROUGH MUCH OF THE  
PERIOD, AND SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION FORECAST TOOLS. IN  
ALASKA, ABOVE-NORMAL PRECIPITATION IS GENERALLY FAVORED ACROSS THE STATE WITH  
UNSETTLED WEATHER BENEATH A MID-LEVEL TROUGH CONTINUING. MEANWHILE,  
ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR HAWAII CONSISTENT WITH THE  
CONSOLIDATION OF TOOLS.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 11, AND 30% 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, WITH  
GOOD AGREEMENT IN THE OVERALL CIRCULATION PATTERN FOR THE PERIOD, OFFSET BY  
WEAKER SIGNALS AND SOME DISAGREEMENT AMONG PRECIPITATION AND TEMPERATURE TOOLS.  
 
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 1991-2020 BASE PERIOD MEANS AS REFERENCE IN  
THE CLIMATE OUTLOOKS.  
 
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON MAY  
16.  
 
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:  
19980514 - 19750430 - 20030420 - 19640501 - 19980519  
 
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:  
19980516 - 19980511 - 19750428 - 20030420 - 19640430  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR MAY 12 - 16 2024  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A B OREGON A B NRN CALIF A N  
SRN CALIF A A IDAHO A B NEVADA A N  
W MONTANA A B E MONTANA A B WYOMING A N  
UTAH A A ARIZONA A A COLORADO A A  
NEW MEXICO N A N DAKOTA A N S DAKOTA A N  
NEBRASKA A N KANSAS A A OKLAHOMA N A  
N TEXAS B A S TEXAS B A W TEXAS B A  
MINNESOTA A N IOWA A N MISSOURI N N  
ARKANSAS B N LOUISIANA B A WISCONSIN A N  
ILLINOIS N N MISSISSIPPI B A MICHIGAN N N  
INDIANA N N OHIO N N KENTUCKY B N  
TENNESSEE B A ALABAMA B A NEW YORK N A  
VERMONT N A NEW HAMP N A MAINE A A  
MASS N A CONN N A RHODE IS N A  
PENN N A NEW JERSEY N A W VIRGINIA B A  
MARYLAND N A DELAWARE N A VIRGINIA N A  
N CAROLINA N A S CAROLINA B A GEORGIA B A  
FL PNHDL B A FL PENIN A A AK N SLOPE B A  
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A  
AK S INT B A AK SO COAST B A AK PNHDL B A  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR MAY 14 - 20 2024  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A N OREGON A B NRN CALIF A N  
SRN CALIF A A IDAHO A N NEVADA A N  
W MONTANA A N E MONTANA A A WYOMING A A  
UTAH A A ARIZONA A A COLORADO A A  
NEW MEXICO A N N DAKOTA A A S DAKOTA A A  
NEBRASKA A A KANSAS A A OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS A N  
MINNESOTA A A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN A A  
ILLINOIS A A MISSISSIPPI N A MICHIGAN N A  
INDIANA N A OHIO N A KENTUCKY N A  
TENNESSEE N A ALABAMA N A NEW YORK N A  
VERMONT N A NEW HAMP N A MAINE A A  
MASS N A CONN N A RHODE IS N A  
PENN N A NEW JERSEY N A W VIRGINIA N A  
MARYLAND N A DELAWARE N A VIRGINIA N A  
N CAROLINA N A S CAROLINA N A GEORGIA N A  
FL PNHDL N A FL PENIN A A AK N SLOPE B A  
AK ALEUTIAN B A AK WESTERN B A AK INT BSN B A  
AK S INT B A AK SO COAST B A 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.  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page