Policy Changes, Technological Advances in NOAA

The beginning of a new year can often bring about changes in companies and organizations.  NOAA is no exception.  They continue to try to find ways to improve communication with the general public, redefine how they classify certain weather phenomena, and gather data for forecasting.  Here are a few changes occurring in the government-based weather industry this year.


Storm Prediction Center

As someone who has taught numerous sections of introductory meteorology over several college terms, I can recite the criteria for classifying a thunderstorm as severe by heart:

1) Hail greater than 3/4 or 0.75 inches in diameter
2) Wind gusts in excess of 50 knots or 58 mph
3) A tornado (duh)

The SPC has changed the parameters of #1 in the list above.  Severe hail will now begin at one inch in diameter.  This will obviously cut down the number of severe hail reports when compared to previous years.  Just keep that in mind in case a lazy news report meets your eye this Spring/Summer.

National Hurricane Center

In response to the needs of emergency managers in coastal areas as well as improved forecasting of tropical cyclones, the NHC has determined they can let the public know of watches and warnings 12 hours earlier.  Watches will now be issued 48 hours in advance while warnings will be issued 36 hours in advance.

This is a somewhat trivial change, if you ask me.  With around-the-clock news and weather coverage, the general public is often well-informed of the threat of tropical cyclones days before they strike land.  It’s not as if a watch from the National Weather Service causes people to suddenly say, “Oh, there might a hurricane in a couple days.”

My guess is that this has more to do with government red tape than anything else.  An emergency manager may not be able to implement evacuation plans until official word of impending doom.  Maybe a better way of stating it is this: if an emergency manager begins mass evacuations based upon what they see on TV and nothing happens, they might have some explaining to do.  Call it a net.

National Center for Environmental Prediction

Here’s something that makes a lot of sense.  In the world of forecasting, all computer models begin with an initial set of data from which to begin the forecast.  These initial data are gathered from observations around the globe.  These observations are not evenly distributed.  There are generally more observations in the high populated areas along the coasts.  Where observations are really sparse is over that 71% of the globe that’s covered by water.  There are some observations over the water, but the density is far less than that over land, especially in North America.

The lack of observations over water, especially the Pacific Ocean, can create problems in forecasting the weather across the continent.  In the middle latitudes, the prevailing wind is westerly and most storm systems come across the Pacific before crossing through the U.S. and Canada.  The lack of observations out over the North Pacific as the storm passes can hinder a computer model’s ability to properly predict the storm as it comes ashore.  NOAA is now trying to remedy this problem.

NOAA Gulfstream IV aircraft. Image from NOAA. Click for larger image.

The NOAA Gulfstream IV will now traverse the North Pacific on a daily basis to measure temperature, moisture, pressure, and wind throughout the region.  These data will be transferred back to NCEP headquarters and used in the forecast models.  In theory, this should help improve the accuracy of weather forecasts 4-7 days out.  As I’ve noted on this blog in the past, NCEP admits their forecasts lose accuracy in the long-term.  It’s possible that having better information about the weather over the open Pacific Ocean will improve these forecasts.  According to the linked article, preliminary studies showed 10-15% improvement in rainfall forecasts.  It’s a step in the right direction.

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