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6-10 Day outlooks are issued daily between 3pm & 4pm Eastern Time. All forecasts issued on weekends are completely automated while all weekday outlooks are modified by the forecaster.
 
Please refer to the U.S. Prognostic Discussion for an explanation of terms and symbols used on these maps.


 
 
HOME> Outlook Maps> Prognostic Map Discussion
 
Prognostic Discussions
Valid: Dec 18 - 22, 2018 (6-10 Day Outlook)
Valid: Dec 20 - 26, 2018 (8-14 Day Outlook)
Issued: Dec 12, 2018

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EST WED DECEMBER 12 2018 
 
6-10 DAY OUTLOOK FOR DEC 18 - 22 2018 
 
TODAY'S ENSEMBLE MODELS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA  
CIRCULATION PATTERN OVER NORTH AMERICA FOR THE 6-10 DAY PERIOD. AN AMPLIFIED  
TROUGH IS PREDICTED OVER WESTERN MAINLAND ALASKA EXTENDING SOUTHEASTWARD OFF THE COAST OF NORTHWESTERN NORTH AMERICA. RIDGING IS FORECAST DOWNSTREAM OF THIS
TROUGH OVER MUCH OF THE INTERIOR WESTERN CONUS EXTENDING TO THE NORTHERN PLAINS. TODAY'S MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE ENSEMBLE MEAN SOLUTIONS FROM THE GEFS AND ECMWF. BELOW NORMAL HEIGHTS ARE FORECAST ACROSS ALASKA, WHILE ABOVE NORMAL HEIGHTS ARE GENERALLY FORECAST ACROSS MUCH OF THE CONUS. NEAR TO SLIGHTLY BELOW NORMAL HEIGHTS ARE FORECAST ACROSS THE SOUTHEASTERN CONUS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF MAINLAND ALASKA AND THE ALEUTIANS IN ASSOCIATION WITH THE TROUGH PREDICTED IN THE VICINITY. THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES AHEAD OF THIS TROUGH FOR THE ALASKA PANHANDLE. ABOVE NORMAL TEMPERATURES ARE FAVORED FARTHER TO THE EAST ACROSS MUCH OF THE CONUS UNDERNEATH ABOVE NORMAL HEIGHTS AND PACIFIC FLOW EARLY IN THE PERIOD. NEAR NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE FLORIDA PENINSULA, CONSISTENT WITH DYNAMICAL FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS LIKELY FOR THE PACIFIC NORTHWEST EXTENDING EASTWARD TO PARTS OF THE NORTHERN ROCKIES AND THE NORTHERN PLAINS AHEAD OF A MEAN TROUGH PREDICTED OFFSHORE OF NORTHWESTERN NORTH AMERICA. BELOW NORMAL PRECIPITATION IS FAVORED FOR MUCH OF CALIFORNIA EXTENDING EASTWARD ACROSS MUCH OF THE CONUS DUE TO RIDGING AND ABOVE NORMAL HEIGHTS. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR MUCH OF MAINE, CONSISTENT WITH CONSOLIDATION FORECAST TOOLS. THE POTENTIAL FOR SOUTHERN STREAM ENERGY LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR PARTS OF THE SOUTHWEST AND THE SOUTHERN PLAINS. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED ACROSS MUCH OF ALASKA, ASSOCIATED WITH A TROUGH PREDICTED OVER WESTERN PARTS OF THE STATE. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF WESTERN MAINLAND ALASKA DUE TO PREDICTED MEAN LOW-LEVEL OFFSHORE FLOW. THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 20% 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 ASSOCIATED SURFACE TOOLS 8-14 DAY OUTLOOK FOR DEC 20 - 26 2018 TODAY'S MODEL ENSEMBLE MEANS ARE IN FAIR AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN DURING THE 8-14 DAY PERIOD. A UPPER-LEVEL RIDGING IS FORECAST TO AMPLIFY OVER THE NORTHEAST PACIFIC. A LOW AMPLITUDE TROUGH IS GENERALLY FORECAST FARTHER TO THE EAST OVER THE EASTERN AND CENTRAL CONUS, BUT THE GFS AND ECMWF MODELS DIFFER ON THE LOCATION OF THIS TROUGH. THE MANUAL
500-HPA HEIGHT BLEND, BASED PRIMARILY ON THE ENSEMBLE MEANS FROM THE GEFS AND ECMWF, FEATURES NEAR TO ABOVE NORMAL HEIGHTS FOR ALASKA AND MUCH OF THE CONUS, SLIGHTLY BELOW NORMAL 500-HPA HEIGHTS ARE FORECAST FOR PARTS OF THE GULF COAST REGION AND NEAR NORMAL HEIGHTS FOR A MAJORITY OF THE CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE CONUS, CONSISTENT WITH DYNAMICAL FORECAST TOOLS. HOWEVER, AS THE UPPER-LEVEL RIDGE AMPLIFIES OVER THE NORTHEAST PACIFIC, A COOLING TREND MAY OCCUR ACROSS THE NORTH CENTRAL CONUS LATE IN WEEK-2. ABOVE NORMAL TEMPERATURES ARE FAVORED AHEAD OF THE TROUGH AXIS FOR MUCH OF ALASKA AND ALSO ABOVE NORMAL SEA SURFACE TEMPERATURES NEARBY. BELOW NORMAL TEMPERATURES FAVORED FOR PARTS OF THE NORTHERN INTERMOUNTAIN, CONSISTENT WITH DYNAMICAL FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE NORTHWESTERN CONUS DUE TO ONSHORE FLOW AT THE BEGINNING OF THE WEEK-2. DOWNSTREAM RIDGING ACROSS THE WESTERN CONUS LEADS TO ENHANCED PROBABILITIES OF BELOW NORMAL PRECIPITATION FOR MUCH OF THE WESTERN CONUS. BELOW NORMAL PRECIPITATION IS ALSO FAVORED FOR THE MIDDLE MISSISSIPPI VALLEY AND PARTS OF THE CENTRAL PLAINS, CONSISTENT WITH CONSOLIDATION FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE REMINDER OF THE CONUS UNDERNEATH PREDICTED CYCLONIC FLOW. ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH OF ALASKA AHEAD OF FORECAST TROUGHING OVER THE WESTERN BERING SEA. THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 10% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO FAIR AGREEMENT ON THE PREDICTED 500-HPA HEIGHT PATTERN, OFFSET BY DIFFERENCES AMONG THE SURFACE TOOLS ACROSS MUCH OF THE FORECAST DOMAIN. FORECASTER: Y. FAN 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 DECEMBER 20.
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: 19591221 - 19861129 - 19981211 - 19591209 - 19841122
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: 19591209 - 19841121 - 20071220 - 19861128 - 19591221 6-10 DAY OUTLOOK TABLE OUTLOOK FOR DEC 18 - 22 2018 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON A A NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A A E MONTANA A N WYOMING A B UTAH A B ARIZONA A N COLORADO A B NEW MEXICO A N N DAKOTA A N S DAKOTA A B NEBRASKA A B KANSAS A B OKLAHOMA A B N TEXAS A B S TEXAS A A W TEXAS A A MINNESOTA A B IOWA A B MISSOURI A B ARKANSAS A B LOUISIANA A B WISCONSIN A B ILLINOIS A B MISSISSIPPI A B MICHIGAN A B INDIANA A B OHIO A B KENTUCKY A B TENNESSEE A B ALABAMA A B NEW YORK A B VERMONT A N NEW HAMP A N MAINE A A MASS A B CONN A B RHODE IS A B PENN A B NEW JERSEY A B W VIRGINIA A B MARYLAND A B DELAWARE A B VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA A B FL PNHDL A B FL PENIN N B AK N SLOPE B A AK ALEUTIAN B A AK WESTERN B N AK INT BSN B A AK S INT B A AK SO COAST B A AK PNHDL A A 8-14 DAY OUTLOOK TABLE OUTLOOK FOR DEC 20 - 26 2018 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON A B NRN CALIF A B SRN CALIF A B IDAHO N B NEVADA A B W MONTANA N N E MONTANA A A WYOMING A N UTAH A B ARIZONA A N COLORADO A A NEW MEXICO A A N DAKOTA A N S DAKOTA A N NEBRASKA A N KANSAS A N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA A N IOWA A N MISSOURI A N ARKANSAS A A LOUISIANA A N WISCONSIN A N ILLINOIS A N MISSISSIPPI A N 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 N 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 A AK N SLOPE N 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 N 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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Prognostic Discussion, Surface Forecasts, 500mb Heights and Anomalies, Time Series of Surface Forecast Skill, Model Guidance Used Our Mission, Who We Are, CPC Information, CPC Web Team
 

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