Weather
NOAA just released their weather outlook for December 2014. This is big news as December is the first real ski season month of the 2014/15 winter season.
NOAA continues to stick with the El Nino pattern for the USA.
The good news is that NOAA is forecasting above average precipitation in nearly every Western US State.
Northern California is especially favored with the Tahoe area highly favored to get above average precipitation in December. Utah, Nevada, Arizona, New Mexico, Colorado, and Oregon are also in the above average precipitation zone. Lets hope they’re right.
The bad news is that many of the Western States are also forecast to receive above average temperatures in December. Alaska, California, Oregon, Washington, and Nevada are all forecast to have above average temperatures in December.
NOAA December 2014 Outlook Discussion:
30-DAY OUTLOOK DISCUSSION FOR DECEMBER 2014 THE OUTLOOK FOR DECEMBER 2014 IS DECIDEDLY UNCERTAIN AT THIS POINT. THERE ARE SEVERAL COMPETING INFLUENCES THAT ARE YET TO BE CLEARLY RESOLVED IN EITHER THE STATISTICAL OR DYNAMICAL TOOLS. LET'S FIRST BEGIN WITH THE DYNAMICAL MODEL GUIDANCE. MONTHLY FORECASTS FROM THE NMME AND IMME ARE FAIRLY MILD ACROSS MUCH OF THE CONUS, ESPECIALLY THE NORTHERN AND WESTERN PORTIONS. THIS IS A REASONABLE SOLUTION GIVEN THE GENERAL WARM ENSO SIGNAL. HOWEVER, THERE IS LITTLE INDICATION THAT A ROBUST ENSO RESPONSE IN THE EXTRATROPICS CAN BE SUSTAINED ABSENT SOME REASONABLY CANONICAL EQUATORIAL CONVECTIVE ANOMALIES CONSISTENT WITH AN EL NINO. CURRENTLY, THE CONVECTIVE STATE OF THE EQUATORIAL PACIFIC IS SOMEWHAT INCONSISTENT WITH WHAT WOULD OTHERWISE BE EXPECTED. SO IN THIS SENSE, MODEL GUIDANCE INITIALIZED WEEKS AGO THAT INDICATE AN ENSO-LIKE FOOTPRINT OVER NORTH AMERICA ARE SOMEWHAT SUSPECT. ADDING TO THE UNCERTAINTY IS THE FACT THAT MORE RECENT GUIDANCE FROM THE CFS AND ECMWF THAT EXTENDS AT LEAST THROUGH THE MIDDLE OF DECEMBER INDICATES A DIFFERENT PATTERN FOR THE FIRST TWO WEEKS OF THE MONTH, WITH ABOVE-NORMAL TEMPERATURES CENTERED IN THE EASTERN CONUS (WITH THE CFS WARMER THAN THE ECMWF), AND NEAR- TO BELOW-NORMAL TEMPERATURES CENTERED OVER PARTS OF THE WEST. THIS LATER GUIDANCE IS SLIGHTLY PREFERRED, BUT THE TYPICAL LOW FORECAST SKILL IS UNDERSTOOD. THE CURRENT AND FORECAST STATE OF THE MJO MAY HAVE SOME IMPLICATIONS FOR THE MONTHLY FORECAST. THIS, TOO, IS UNCERTAIN SINCE THERE DOES NOT SEEM TO BE A STRONG ATMOSPHERIC RESPONSE IN THE SUBTROPICS YET, CASTING DOUBT ON WHETHER THE ONGOING EVENT WILL SUBSTANTIALLY MODULATE NORTH AMERICAN CLIMATE. SHOULD A ROBUST MJO PROPAGATE FROM THE INDIAN OCEAN TO THE PACIFIC, THE RESPONSE LATER IN THE MONTH COULD BALANCE OUT A WARMER SIGNAL INDICATED EARLY BY THE FORECAST EVOLUTION OVER THE NEXT WEEK OR TWO. FINALLY, THERE ARE SIGNS IN THE CURRENT MEDIUM RANGE GUIDANCE THAT RELOADING OF ANOMALOUSLY COLD AIR IN WESTERN CANADA COULD OCCUR BY LATE NOVEMBER. THIS IS BEST SUPPORTED BY THE LATEST CANADIAN AND ECMWF ENSEMBLE AND DETERMINISTIC GUIDANCE. SUCH A SCENARIO CASTS MORE DOUBT ON THE WARM ENSO RESPONSE OVER SOUTHERN CANADA AND THE NORTHERN CONUS. IN LIGHT OF THE AFOREMENTIONED DISCUSSION, THERE IS RELATIVELY LITTLE COVERAGE ON THE 0.5 LEAD MONTHLY TEMPERATURE MAP. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR THE IMMEDIATE WEST COAST BASED ON GOOD MODEL CONSENSUS AND STATISTICAL GUIDANCE BASED ON PACIFIC SSTS. UNCERTAINTY INCREASES IN THE PACIFIC NORTHWEST SOMEWHAT. ABOVE-NORMAL TEMPERATURES ARE FAVORED IN THE NORTHEASTERN CONUS AT THE INTERSECTION OF SIGNALS FROM ENSO, MJO, AND RECENT MODEL GUIDANCE. CONFIDENCE HERE IS STILL FAIRLY LOW AS INDICATED BY MEAGER PROBABILITIES. BELOW-NORMAL TEMPERATURES ARE WEAKLY FAVORED FOR THE SOUTH-CENTRAL CONUS WHERE THE ENSO SIGNAL IS STRONGEST AND THERE IS MORE SUPPORT FROM MODEL GUIDANCE. THE NORTHWARD EXTENSION IS BASED ON THE DISTINCT POSSIBILITY THAT ANOTHER ARCTIC AIRMASS MOVES SOUTHWARD EAST OF THE ROCKIES EARLY IN THE MONTH. IF THIS OCCURS, EVEN AN EMERGENCE OF A STATIONARY ENSO SIGNAL LATER IN THE MONTH WOULD STILL NOT UNDO THE ODDS FOR BELOW-NORMAL TEMPERATURES OVER THE INDICATED REGION. FOR PRECIPITATION, A GENERAL CONSENSUS OF ENSO IMPACTS AND MODEL GUIDANCE IS USED, WITH LOW PROBABILITIES INDICATING THE LOW CONFIDENCE IN LIGHT OF THE ABOVE FACTORS. IF ROBUST MJO IMPACTS ARE REALIZED EARLY IN THE MONTH, ABOVE-MEDIAN PRECIPITATION MIGHT EXTEND FARTHER NORTH INTO PARTS OF THE OHIO VALLEY AT THE EXPENSE OF RAINFALL NEAR THE GULF COAST. UNCERTAINTY IS ALSO ESPECIALLY HIGH OVER THE PACIFIC NORTHWEST, WHERE THERE ARE MULTIPLE CONFLICTING SIGNALS.
