Prognostic Discussion for Monthly Outlook
NWS Climate Prediction Center College Park MD
830 AM EST Thu Feb 20 2020


30-DAY OUTLOOK DISCUSSION FOR MARCH 2020

The March temperature and precipitation outlooks depict limited forecast 
coverage and only modestly elevated probabilities from that expected from 
climatology due to above-average uncertainty - a result of a number of factors. 
This is true for both monthly mean temperatures and monthly total precipitation 
amounts and for both above- and below-normal tercile categories. 
 
In the Tropics, the MJO, although active, is being affected by other 
subseasonal coherent tropical variability (i.e., atmospheric Kelvin wave and 
Equatorial Rossby wave activity), so forecasts of its evolution by common 
guidance (e.g., RMM index) are non-canonical and varied in nature. Constructive 
and destructive interference of these other tropical modes can make it 
difficult to have high forecast confidence and fully interpret observed and 
forecast amplitude and eastward propagation of the main MJO envelope. Most RMM 
forecasts, however, do indicate varying degrees of forecast amplitude and 
eastward propagation over the next few weeks across the Pacific Ocean into the 
Western Hemisphere. In fact, at the current time, a strong enhanced convective 
anomaly has been in place across the west-central Pacific Ocean along the 
equator. The March temperature and precipitation outlooks do utilize some MJO 
predictive information from both lagged and conterminous composite as well as a 
multi-linear regression forecast tool that targets temperature and 
precipitation contributions from the MJO. 

Week 3-4 dynamical model guidance from both the CFS and ECMWF monthly 
prediction systems are also utilized to aid prediction during the first half of 
March as well as monthly integrations from the CFS for the entire month of 
March. The monthly NMME forecasts are not considered due to considerably 
outdated initial conditions used for their March predictions. The higher than 
average uncertainty (potential and strength of any teleconnection from the MJO 
and weak signals from both statistical forecast tools and dynamical model 
guidance results in a large region of "Equal Chances" (EC) across the forecast 
domain for both temperature and precipitation.
   
Above-normal monthly mean temperatures are favored for parts of northern and 
western Alaska due to strong long term positive temperature trends primarily 
linked to reduced sea ice coverage in nearby waters. Some signals from 
dynamical model guidance support favored above-normal temperatures for 
California, Nevada and parts of neighboring states at only modest probability 
departures from the region's climatological odds. Both the MJO and dynamical 
model guidance serve as the forecast basis for elevated odds of below-normal 
temperatures for the central and southern Plains, Ohio Valley, Southeast and 
mid-Atlantic regions.

For precipitation, prospects of a pattern favoring below-normal temperatures 
across parts of the eastern CONUS also favors below-normal precipitation for 
parts of the central and northern Mississippi Valley, Ohio Valley and Great 
Lakes. The most likely region of enhanced odds for above-normal precipitation 
resides along the Gulf and south Atlantic coasts. Forecast ridging and a 
potential northward shifted storm track favors below-normal precipitation for 
Arizona and the West Coast as well as the Alaska Panhandle. Consensus of 
dynamical model guidance favors above-normal monthly total precipitation 
amounts for northern and western Alaska during March 2020.

FORECASTER: Jon Gottschalck

The climatic normals are based on conditions between 1981 and 2010, following
the World Meteorological Organization convention of using the most recent 3 
complete decades as the climate reference period.  The probability anomalies
for temperature and precipitation based on these new normals better represent
shorter term climatic anomalies than the forecasts based on older normals.

An updated monthly outlook... for Mar will be issued on Sat February 29 2020

These outlooks are based on departures from the 1981-2010 base period.
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