Unformatted text preview: Elements of Meteorology Notes, Fall 2006 — 11:670:201 W? m Forecasting
i. WMO - World Meteorological Organization (UN)
ii. National Weather Service (NW8)
1. NCEP - National Centers for Environmental Prediction 2. WFO — Weather Forecast Office — a NWS office that is responsible for a
speciﬁc area of counties or parishes (in Louisiana)
3. CPC — Climate Prediction Center
4. TPCINHC — Tropical Prediction Center! National Hurricane Center
5. SP0 — Storm Prediction Center — severe thunderstorms and tornadoes
b. Methods of forecasting i. Persistence — Stipulates that future weather will remain like past/present
weather. ii. Steady—stateltrendinowcasting —— Assumes that current features will retain their
current strength and motion. iii. Analog —- Conditions resemble features that produced certain conditions in the
past — "Best—fit" iv. Climatology — based upon average weather — ”temperatures will be ‘near
normal’" v. Ensemble — Average together several computer models or several runs of the
same model to come up with a new solution.
c. Probability of Precipitation i. There is an N% chance that any random point within the area will receive
ii. Based on the analog method. d. Numerical Weather Prediction — Based on the presumption that the atmosphere behaves
like a ﬂuid. i. Complicated equations that take several variables into account use calculus to
predict how current conditions will change.
ii. This process must be reiterated to forecast out to periods in time and requires
millions and millions of calculations per second.
iii. Made practical by the computer age.
iv. Numerical weather prediction must only be used as guidance at this point. It is
not to be solely relied upon to make forecasts.
e. Watches and Warnings
i. A watch means that conditions are favorable for a speciﬁc weather event to
occur. Meant to get the public to keep vigilant.
ii. Lead time — in a warning, the time between the warning issuance and the event’s
iii. A warning means that the said event is either imminent or occurring, and lead
time depends on the event. Tornado warnings are issued minutes before the event, whereas hurricane warnings are issued about 24 hours before arrival of
the conditions. ' f. Short-term forecasts (within 24 hours) are about 90 percent accurate. Accuracy
decreases as time into the future increases. 9. Forecasts come from private agencies like AccuWeather, but official watches and
warnings come from public agencies, such as NOAA, NWS, and their sub-agencies h. AWIPS — Advanced Weather Interactive Processing System. Part of recent
modernization, it is a method of classifying forecast products issued by WFOs. 1.. Thunderstorms and Tornadoes
3. Stages of Thunderstorm Development i. Cumulus — Millions and millions of air parcels rise and cool to their dew points. ii. Growing — Vertical development of the cumulonimbus cloud becomes more
robust. 14 ...
View Full Document
- Spring '08