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%.
December 22, 2017 - The Climate Prediction Center outlook for Mariposa County through January 4, 2018 shows a below average chance of rain/snow along with a probability of above average temps.
The following has a 6-10 day outlook followed by an 8-14 day outlook.
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD 300 PM EST THU DECEMBER 21 2017 6-10 DAY OUTLOOK FOR DEC 27 - 31 2017 TODAY'S MODEL FORECASTS ARE IN GOOD AGREEMENT ON A PREDICTED AMPLIFIED 500-HPA CIRCULATION PATTERN FOR THE 6-10 DAY PERIOD. ENSEMBLE PREDICTION SYSTEMS FROM THE NCEP GEFS, ECMWF, AND ENVIRONMENT CANADA PREDICT A STRONG RIDGE OVER THE NORTH PACIFIC AND ALASKA, A DOWNSTREAM TROUGH EXTENDING FROM NORTHERN QUEBEC INTO THE NORTH-CENTRAL CONUS, AND ABOVE NORMAL 500-HPA HEIGHTS OVER THE WESTERN CONUS AND ACROSS THE SOUTHERN CONUS. THE 500-HPA FLOW PATTERN OF THE ECMWF ENSEMBLE PREDICTION SYSTEM IS WEIGHTED MORE HEAVILY IN THE OFFICIAL 500-HPA HEIGHT BLEND BASED ON CONSIDERATIONS OF RECENT FORECAST SKILL. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MOST OF ALASKA, EXCEPT FOR SOUTHEASTERN REGIONS OF THE STATE, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. BELOW NORMAL TEMPERATURES ARE MORE LIKELY FOR THE ALASKA PANHANDLE, UNDER NORTHERLY FLOW AHEAD OF THE PREDICTED RIDGE. BELOW NORMAL TEMPERATURES ARE LIKELY FOR A LARGE AREA OF THE CONUS, UNDER A PREDICTED AMPLIFIED TROUGH AND AN INFLUX OF ARCTIC AIR. PROBABILITIES EXCEED 80 PERCENT OVER A LARGE AREA OF THE NORTHERN CONUS FROM THE NORTHERN PLAINS ACROSS THE GREAT LAKES TO NEW ENGLAND. UNDER PREDICTED SOUTHEASTERLY FLOW, ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE FLORIDA PENINSULA. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FOR LARGE PARTS OF CALIFORNIA INTO THE GREAT BASIN AND SOUTHWEST, UNDER PREDICTED ABOVE NORMAL HEIGHTS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR SOUTHWESTERN ALASKA AND THE ALEUTIANS AHEAD OF A PREDICTED TROUGH. BELOW NORMAL PRECIPITATION IS LIKELY FOR MOST OF ALASKA UNDER A PREDICTED RIDGE. THE PREDICTED TROUGH OVER THE CENTRAL EASTERN CONUS ENHANCES THE PROBABILITY OF ABOVE NORMAL PRECIPITATION FOR THE PARTS OF THE NORTHERN ROCKIES INTO THE GREAT PLAINS STATES AND ACROSS THE CENTRAL AND EASTERN CONUS, FOLLOWING THE PREDICTED MEAN FRONTAL BOUNDARY. BELOW NORMAL PRECIPITATION IS FAVORED FOR CALIFORNIA AND PARTS OF NEVADA AND THE SOUTHWEST UNDER PREDICTED ANOMALOUS NORTHERLY 500-HPA FLOW. THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S GFS SUPERENSEMBLE MEAN 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 MODEL AGREEMENT ON A HIGHLY AMPLIFIED FLOW PATTERN, WITH SOME AREAS OF DISAGREEMENT IN THE PRECIPITATION FORECAST. 8-14 DAY OUTLOOK FOR DEC 29, 2017 - JAN 04, 2018 IN THE WEEK 2 PERIOD, MODEL FORECASTS PREDICT A SLIGHTLY LESS AMPLIFIED 500-HPA TROUGH, RELATIVE TO THE 6-10 DAY PERIOD, AS A RESULT OF INCREASING ENSEMBLE SPREAD AND FORECAST UNCERTAINTY, ALONG WITH SOME EASTWARD PROGRESSION OVER THE CONUS. THE ECMWF AND ENVIRONMENT CANADA ENSEMBLE AVERAGES MAINTAIN A MORE AMPLIFIED TROUGH INTO THE WEEK 2 PERIOD, RELATIVE TO THE NCEP GEFS ENSEMBLE PREDICTION SYSTEM. ABOVE NORMAL TEMPERATURES REMAIN LIKELY FOR NORTHWESTERN MAINLAND ALASKA, UNDER THE PREDICTED RIDGE. BELOW NORMAL TEMPERATURES ARE MOST LIKELY FOR THE ALASKA PANHANDLE, UNDER ANOMALOUS NORTHERLY FLOW. BELOW NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR A LARGE AREA OF THE CONUS, UNDER THE PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES ARE LIKELY OVER THE SOUTHWEST CONUS WITH AN INFLUX OF PACIFIC AIR PREDICTED FOR THE REGION. WITH THE PREDICTED RIDGE OVER ALASKA, BELOW NORMAL PRECIPITATION IS LIKELY OVER MOST AREAS OF THE STATE. THE PRECIPITATION FORECAST OVER THE CONUS FOR WEEK 2 IS VERY SIMILAR TO THE 6-10 DAY PERIOD FORECAST. ABOVE NORMAL PRECIPITATION IS LIKELY FROM PARTS OF THE NORTHERN INTERMOUNTAIN REGION EASTWARD ACROSS THE CENTRAL AND EASTERN CONUS. THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 40% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO AN AMPLIFIED PREDICTED CIRCULATION PATTERN, OFFSET BY INCREASING ENSEMBLE SPREAD. FORECASTER: Y. FAN
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%.
Source: NOAA