PPT Slide
Forecasting Excessive Rainfall
(3 or more inches) in a 12 to 24 hour period
----- ----- Is an 850/700 mb theta-e ridge present ?
----- ----- Is the sfc-500 mb RH > 70 % and PW > 1 in and/or 120 % of normal?
----- ----- Is a short wave, cyclonic circulation (lobe), or jet streak expected over the area?
----- ----- Is a water vapor (6.7 mm) and Precipitable Water Plume over or approaching the area?
----- ----- Is positive 850/700 mb theta-e advection present?
----- ----- Is sfc-500 mb RH > 70 % and PW > 1.5 and/or > 140 % of norm?
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other meteorological variables to consider: speed of system, regeneration, and surface features such as winds, dew points and boundaries.