UFSP 100 Weather Forecasting
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UFSP 100 Weather Forecasting Ross A. Lazear
description
UFSP 100 Weather Forecasting. Ross A. Lazear. Why is forecasting the weather so difficult?. • Imagine a rotating sphere 8,000 miles in diameter -Has a bumpy surface -Surrounded by 40-km deep mixture of different gases whose concentrations vary both spatially and over time - PowerPoint PPT Presentation
Transcript of UFSP 100 Weather Forecasting
UFSP 100Weather Forecasting
Ross A. Lazear
Why is forecasting the weather so difficult?
• Imagine a rotating sphere 8,000 miles in diameter
-Has a bumpy surface-Surrounded by 40-km deep mixture of
different gases whose concentrations vary both spatially and over time
-Heated, along with its gases, by a nuclear reactor 93,000,000 miles away
• Sphere is revolving around the nuclear reactor
-Some locations are heated more during one part of the revolution than others
• Mixture of gases receives inputs from the surface below
-Generally calmly; sometimes violently!
Why is forecasting the weather so difficult?
Why is forecasting the weather so difficult?
.....Now, imagine that after observing this gaseous mixture, you are expected to predict its state at multiple locations on the sphere one, two, or more days into the future.
This is essentially the task encountered every day by a weather forecaster!
Adapted from Ryan, 1982, Bulletin of the American Meteorological Society
Why the discrepancy?
Forecasting is often extremely challenging!
There are *many* forecasts made available to the public…
*National Weather Service*The Weather Channel*AccuWeather*Wunderground*Your iPhone…etc…
*Nowcasting (Up to six hours)
*Short/medium range (Up to 7-10 days)
*Long range/intraseasonal/seasonal
*Climate (IPCC)
Types of Forecasts
*Nowcasting (Up to six hours)
*Short/medium range (Up to 7-10 days)
*Long range/intraseasonal/seasonal
*Climate (IPCC)
Types of Forecasts
When will the thunderstorm hit?
When will the snow taper?
When will the rain change to snow/sleet/freezing rain?
Nowcasting
Radar Satellite SoundingsNowcasting Tools
Nowcasting Tools
Surface (airport) observations
*Nowcasting (Up to six hours)
*Short/medium range (Up to 7-10 days)
*Long range/intraseasonal/seasonal
*Climate (IPCC)
Types of Forecasts
Short/Medium Range ForecastingComputer models needed!
Models use:-Current surface observations-Upper air observations-Previous forecast
…and then…
Short/Medium Range Forecasting
From MetEd / UCAR
ModelsGFS - 16 days, global, U.S.A.NAM - 84 hours, N. America, U.S.A.HRRR/Rapid Refresh, 18 hours, U.S.A.ECMWF - 10 days, global, U.K.UKMET - global, U.K.NOGAPS - global, U.S.A. (Navy)JMA - JapanCMC - Canada
WRF - Multiple domains, also run locally at Albany!
*Nowcasting (Up to six hours)
*Short/medium range (Up to 7-10 days)
*Long range/intraseasonal/seasonal
*Climate (IPCC)
Types of Forecasts
Long Range/Intraseasonal/SeasonalVarious global “signals” that help meteorologists forecast on longer time scales.
-ENSO (El Niño/La Niña)
Long Range/Intraseasonal/SeasonalAlso…
-Lots of other complex atmospheric waves in the tropics…
From Dr. Paul Roundy, UAlbany
Hurricane Sandy, October 2012
National Hurricane CenterForecast for Hurricane Sandy5 PM EDT October 24, 2012
Evening of October 25, 2012
Other forecast challenges: Precipitation type!
Forecast temperature profile for March 19, 2013 winter storm
ACTUAL temperature profile for March 19, 2013 winter storm...Close call for a heavy sleet storm!
Other forecast challenges: Precipitation type!
