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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 20 - 24, 2018 (6-10 Day Outlook)
Valid: Dec 22 - 28, 2018 (8-14 Day Outlook)
Issued: Dec 14, 2018

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 
300 PM EST FRI DECEMBER 14 2018 
 
6-10 DAY OUTLOOK FOR DEC 20 - 24 2018 
 
TODAY'S ENSEMBLE MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED 500-HPA  
CIRCULATION PATTERN OVER NORTH AMERICA FOR THE 6-10 DAY PERIOD. A TROUGH IS  
PREDICTED OVER WESTERN ALASKA. RIDGING IS FORECAST OVER MUCH OF THE WESTERN  
CONUS. MEAN TROUGHING IS FORECAST FARTHER TO THE EAST ACROSS MUCH OF EASTERN NORTH AMERICA. 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 MOST OF ALASKA AND THE EASTERN CONUS, WHILE ABOVE NORMAL HEIGHTS ARE GENERALLY FORECAST ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF WESTERN 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 AND PARTS OF SOUTHEASTERN MAINLAND ALASKA. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE CONUS UNDERNEATH MEAN TO ABOVE NORMAL HEIGHTS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE PACIFIC NORTHWEST DUE TO THE POTENTIAL FOR ENHANCED PACIFIC FLOW. BELOW NORMAL PRECIPITATION IS LIKELY FOR MUCH OF SOUTHERN CALIFORNIA EXTENDING EASTWARD ACROSS MUCH OF THE INTERIOR WEST DUE TO RIDGING AND ABOVE NORMAL HEIGHTS. BELOW NORMAL PRECIPITATION IS ALSO FAVORED ACROSS MUCH OF THE MISSISSIPPI VALLEY CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLES. NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED ACROSS THE GREAT LAKES REGION TO NORTHERN NEW ENGLAND UNDERNEATH PREDICTED MEAN CYCLONIC FLOW. THE POTENTIAL FOR SOUTHERN STREAM ENERGY LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR THE FLORIDA PENINSULA. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED ACROSS MUCH OF NORTHEASTERN ALASKA, SOUTH COAST OF ALASKA AND THE ALEUTIANS, IN ASSOCIATION 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 20% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 20% OF YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO RELATIVELY GOOD AGREEMENT AMONG MODEL SOLUTIONS AND ASSOCIATED SURFACE TOOLS 8-14 DAY OUTLOOK FOR DEC 22 - 28 2018 TODAY'S MODEL SOLUTIONS ARE IN POOR AGREEMENT ON THE PREDICTED 500-HPA PATTERN OVER THE FORECAST DOMAIN DURING THE WEEK-2 PERIOD. THE STRONG RIDGE PREDICTED OVER THE WESTERN CONUS DURING THE 6-10 DAY PERIOD IS FORECAST TO WEAKEN AND RETROGRADE OFF THE WEST COAST OF THE CONUS DURING WEEK-2. DOWNSTREAM, BROAD, RELATIVELY LOW AMPLITUDE CYCLONIC FLOW IS FORECAST OVER MUCH OF THE CONUS. HOWEVER, MODELS DISAGREE ON THE PLACEMENT OF THE MEAN TROUGH AXIS WITH THE ECMWF ENSEMBLE MEAN FARTHER TO THE WEST WITH THIS FEATURE RELATIVE THE GEFS. RIDGING IS GENERALLY FORECAST ACROSS EASTERN ALASKA AHEAD OF A TROUGH EXPECTED OVER THE ALEUTIANS AND THE BERING SEA. NEAR TO ABOVE NORMAL HEIGHTS ARE INDICATED ACROSS MUCH OF THE WESTERN AND SOUTHERN CONUS AND ALASKA. SLIGHTLY BELOW NORMAL HEIGHTS ARE FAVORED FOR MUCH OF THE NORTHEASTERN CONUS AND NORTH-CENTRAL CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS PARTS OF THE CENTRAL AND SOUTHWESTERN CONUS IN ASSOCIATION WITH RIDING (PARTICULARLY EARLY IN THE PERIOD). SINCE THIS RIDGING IS FORECAST TO WEAKEN AS IT RETROGRADES OFF THE COAST, HEIGHT DEPARTURES ASSOCIATED WITH PREDICTED DOWNSTREAM TROUGHING ARE RELATIVE MODEST. THIS RELATIVELY LOW AMPLITUDE FLOW COMBINED WITH PREDICTED MJO INFLUENCES LEADS TO FAVORED ABOVE NORMAL TEMPERATURE FOR MUCH OF THE EASTERN
CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR SOUTHEASTERN PARTS OF ALASKA, THE ALEUTIANS AND THE ALASKA PANHANDLE IN ASSOCIATION WITH RIDGING AND ABOVE NORMAL HEIGHTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF NORTHWESTERN MAINLAND ALASKA. AS A RIDGE RETROGRADES OFF THE WEST COAST OF THE CONUS, BELOW NORMAL PRECIPITATION IS INCREASINGLY LIKELY ACROSS MUCH OF THE SOUTHWESTERN CONUS. MEAN CYCLONIC FLOW LEADS TO FAVORED ABOVE NORMAL PRECIPITATION FOR PARTS OF THE CENTRAL CONUS. BELOW NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR THE MIDDLE AND SOUTHERN ATLANTIC SEABOARD AND THE EASTERN GULF COAST, EXCEPT FOR PARTS OF THE FLORIDA PENINSULA, CONSISTENT WITH PRECIPITATION ESTIMATES FROM THE GEFS AND ECMWF ENSEMBLES. ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH OF ALASKA AHEAD OF FORECAST TROUGHING OVER THE BERING SEA. 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, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO MODEL DISAGREEMENTS ASSOCIATED WITH A PREDICTED TRANSITIONAL PATTERN. FORECASTER: QIN Z 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: 19861129 - 20011218 - 19591213 - 20071220 - 19791225
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: 20011219 - 20071220 - 19861128 - 19881124 - 19591213 6-10 DAY OUTLOOK TABLE OUTLOOK FOR DEC 20 - 24 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 N 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 A B S TEXAS A B W TEXAS A B MINNESOTA A A IOWA A B MISSOURI A B ARKANSAS A B LOUISIANA A B WISCONSIN A A ILLINOIS A B MISSISSIPPI A B MICHIGAN A A INDIANA A B OHIO A N KENTUCKY A B TENNESSEE A B ALABAMA A B NEW YORK A A VERMONT A A NEW HAMP A A MAINE A A MASS A N CONN A N RHODE IS A N PENN A N NEW JERSEY A N W VIRGINIA A B MARYLAND A N DELAWARE A B VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA A B FL PNHDL A A FL PENIN N A AK N SLOPE B N AK ALEUTIAN B N AK WESTERN B B AK INT BSN B N AK S INT N A AK SO COAST N A AK PNHDL A A 8-14 DAY OUTLOOK TABLE OUTLOOK FOR DEC 22 - 28 2018 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON A N NRN CALIF A N SRN CALIF A B IDAHO N N NEVADA A N W MONTANA N N E MONTANA A A WYOMING A A UTAH A N ARIZONA A B 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 A MINNESOTA A A IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A N WISCONSIN A N ILLINOIS A A MISSISSIPPI A N MICHIGAN A N INDIANA A A OHIO A A KENTUCKY A N TENNESSEE A N ALABAMA A N NEW YORK A N VERMONT A N NEW HAMP A N MAINE A N MASS A N CONN A N RHODE IS A N PENN A N NEW JERSEY A N W VIRGINIA A N MARYLAND A N DELAWARE A B VIRGINIA A B N CAROLINA N B S CAROLINA N B GEORGIA A N FL PNHDL A N FL PENIN A A AK N SLOPE B A AK ALEUTIAN A A AK WESTERN B A AK INT BSN N A AK S INT A A AK SO COAST A A AK PNHDL N 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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