Weather - Precipitation

Meteorology versus Meteors

If a meteorologist studies weather, what do we call a person who studies meteors? In the days of ancient Greeks, meteorology was the study of the atmosphere, and anything that came out of it - rain, sleet, snow, hail. So, not too surprising that meteorology became the study of weather. But what about meteors? The science of meteors is called Meteorics.  Accordingly, a student of meteors is a meteoriticist. A tongue twister to be sure.

HT-2



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Weather Discussion - March 2017 

by Richard Schreiber


What's Involved with Weather Forecasting


Even a high-level discussion of weather forecasting would take many pages of text and a lot of time and effort to write and to read.  So what I have done instead is to create an outline of the tools and concepts involved -- think of this as a course outline. You can then pursue any of the topics that are interesting to you.  A web search will produce plenty of resources beyond the few I have provided: many are well written and illustrated.


First, an overview


Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location (thanks, Wikipedia).  To be equipped to forecast, meteorologists first need to acquire a lot of data.  Then they apply numerical modeling techniques using supercomputers.  The model output drives predictions which are also refined by actual weather people, in our case the National Weather Service or commercial providers such as the Weather Company.  Results are communicated to individuals and organizations though various means (e.g. the internet, NOAA Weather Radio).  How to communicate to the variety of audiences that want weather predictions is an evolving science in its own right.


The most demanding aspect is probably devising the numerical models used to forecast weather and then acquiring forecasters who are skilled at using and refining the output based on science, experience and intuition.  


The "Outline" (Some references provided - use your own searches to expand on a topic)


1.  Data collection

         Surface weather observation - small scale areas 

                -  NOAA and personal weather stations

                -  Private/public cooperatives: CoCoRaHS,  CWOP, NWS
                   Cooperative Observer 
Program, etc.

                -  Ocean buoy network for marine weather  http://www.ndbc.noaa.gov/


         Large scale weather data obtained from geo-stationary and polar orbiting
          satellites - includes 
both visible and infrared data

                -  precipitation

                -  sea surface temperatures

                -  atmospheric temperature and humidity

                -  sea-ice boundaries

                -  volcanic eruptions, etc. 


          Doppler radar - determines location and velocity of a storm, clouds,
          precipitation, etc.


          Weather balloons - carry instrumentation to help measure conditions like
          humidity, temperature, 
and the wind speed in our atmosphere to around
         100,000 ft. 


         Aircraft weather observations

                -  sensor based observations from commercial and military aircraft,
                AMDAR initiative

                     https://www.wmo.int/pages/prog/www/GOS/ABO/AMDAR/

               -  NOAA "hurricane hunter" aircraft fleet improves forecasting hurricanes
                   and tropical 
cyclones


2.  Data analysis and computer modeling

              Numerical Weather Prediction (NWP) data - uses current observations
              and processes 
with computer models to forecast the future state of
              weather 

                     https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/numerical-weather-prediction

               Data manipulation in preparation for 1 -7 day forecast 


3.  Weather forecasts and weather data products

               "Nowcasts" - short time scales (on the order of a few minutes to a few
                hours) 

                Forecasters rely heavily on an extrapolation of current weather trends  

                Longer time scales - use of numerical model output to develop 3-
                dimensional views 
for various time frames

                Main focus of forecasters 1- 7 days and creation of digital products

                 http://www.nws.noaa.gov/outlook_tab.php      

               Learn to make your own forecasts based on observations of clouds,
               other features, readings from your personal weather station

               Improving numerical models, greater use of model ensembles (use of«
               multiple model 
with different inputs to arrive at a more reliable forecast)

               Forecast reliability: skill, lead time and predictability 

https://www.ametsoc.org/ams/index.cfm/about-ams/ams-statements/statements-of-the-ams-in-force/weather-analysis-and-forecasting/

 

4. Users of weather forecasts and communicating forecast data

               Increasing demand for accurate, specialized forecasts needed by
               agriculture, industry 
and scientific organizations

               Determining best means of communicating forecasts - use of other
               disciplines to 
help identify new opportunities

               Means of distribution:  the web, NOAA Weather radio, broadcast TV,
               marine 
weather fax broadcasting, GRIB data, etc., etc. 



In conclusion, I have undoubtedly overlooked a topic or two or buried an important idea within another topic.  But if I succeeded in giving you an idea of the range and complexity of weather forecasting then it was worth doing the outline.  This could provide suggestions for future monthly articles. 


Mar2017Recap

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February 2017 was a warm month and March continued the trend, based on almost every factor we use to compare past history with the present:

  • Highest monthly mean temperature in ten years
  • 2nd highest high temperature (missing first place by slightly over a half degree!) 
  • Not a single day with a below freezing temperature.  Although not that unusual, there was one year with 6 days where the  temperature fell below 32 degrees F during March
  • Twelve days with a temperature above 80 degrees F.  This is extraordinary as the most recent competitor was 2011 with only 4 days when the temperature exceeded 80 degrees 
  • Third highest low temperature during the month
  • Lowest ten-year monthly heating degree days factor and highest cooling degree days factor

February and March are generally windy months.  This year we had 6 days with gusts exceeding 30 mph and one day with a maximum of 45 mph.  Over our ten-year history we have noted that March and February are surprisingly similar, and historically have maximum gusts in the very same range, i.e. 36 - 51 mph.  

So far this year we have measured 2.53 inches of precipitation, still within the norm, but the March contribution of a scant 0.17 inch won't help our area very much.  But it's too early to jump to conclusions since March is typically not a wet month.  In 2010 by this time we had seen 5.78 inches of precipitation, but that amount was double any other year before or since.

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Richard Schreiber

Comments and suggestions appreciateddschre@att.net


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© Howard Topoff 2011