Precipitation Potential Placement
Precipitation Potential Placement is a derived parameter combining precipitable
water and low-level mean RH to help better place where rainfall will occur.
Research has been published in the National Weather Association Digest in 2003
and stems from research and operational use of this product originally
developed at NESDIS and Rod Scofield for satellite rainfall estimates dating
back to 1981.
Rainfall is usually maximized where the best low level convergence and instability
overlay with the highest values for this parameter.
The risk for heavy rainfall increases as values go up. Additionally, thresholds
for precipitation also change based on temperatures. Onset of rainfall ranges
from around 0.3 inches with temperatures below 30 to 1.0 inches above 80. Values
above 1.0-1.4 inches with temperatures below 60 usually increase the risk for heavy
rainfall while values above 1.6-2.0 inches increase the risk for heavy rainfall
events with temperatures above 60.
For more information, see:
http://www.srh.noaa.gov/ffc/research/finalPP2.htm