Subj : Wx Terms (P)(6) To : All From : Daryl Stout Date : Sun Sep 17 2017 12:04 am PTCHY Patchy PTCLDY Partly Cloudy PTDY On a buoy report, Pressure Tendency is the sign (plus or minus) and the amount of pressure change (hPa) for a three hour period ending at the time of observation. PTLY Partly PTN Portion PTTN pattern PTWC (Pacific Tsunami Warning Center) - The Pacific Tsunami Warning Center in Ewa Beach (pronounced Eva Beach), HI has an international warning responsibility for the entire Pacific and a regional warning responsibility for the State of Hawaii. See also WC/ATWC. PTYPE precipitation type Public Information Statement A narrative statement issued by a National Weather Service Forecast Office that can be used for: 1) A current or expected nonhazardous event of general interest to the public that can usually be covered with a single message (e.g., unusual atmospheric phenomena such as sun dogs, halos, rainbows, aurora borealis, lenticular clouds, and stories about a long-term dry/cold/wet/warm spell). 2) Public educational information and activities, such as storm safety rules, awareness activities, storm drills, etc. 3) Information regarding service changes, service limitations, interruptions due to reduced or lost power or equipment outages, or special information clarifying interpretation of NWS data. For example, this product may be used to inform users of radar equipment outages or special information clarifying interpretation of radar data originating from an unusual source which may be mistaken for precipitation (such as chaff drops, smoke plumes, etc., that produces echoes on the radar display. Public Severe Weather Outlook These are issued when the Storm Prediction Center (SPC) in Norman, Oklahoma anticipates an especially significant and/or widespread outbreak of severe weather. This outlook will stress the seriousness of the situation, defines the threat area, and provides information on the timing of the outbreak. The lead time on this outlook is normally less than 36 hours prior to the severe weather event. Puddle In hydrologic terms, (1) The act of compacting earth, soil clay, etc., by mixing them with water and rolling or tamping the mixture. (2) A compact mass of earth, soil, clay, or a mixture of material, which has been compacted through the addition of water, rolling and tamping. This makes the material less permeable. (3) A small pool of water, usually a few inches in depth and from several inches to several feet in it greatest dimension. Puget Sound Convergence Zone A situation where wind forced around the Olympic Mountains converges over the Puget Sound. Causes extreme variability in weather conditions around Seattle, Washington with some areas of sunshine and others in clouds and rain. Pulse A short burst of electromagnetic energy that a radar sends out in a straight line to detect a precipitation target. The straight line that this pulse travels along is called a radar beam. Pulse Duration The time over which a radar pulse lasts. The pulse duration can be multiplied by the speed of light to determine the pulse length or pulse width. Pulse Length The linear distance in range occupied by an individual pulse from a radar. h = c * t , where t is the duration of the transmitted pulse, c is the speed of light, h is the length of the pulse in space. Note, in the radar equation, the length h/2 is actually used for calculating pulse volume because we are only interested in signals that arrive back at the radar simultaneously. This is also called a pulse width. Pulse Radar A type of radar, designed to facilitate range (distance) measurements, in which are transmitted energy emitted in periodic, brief transmission. Pulse Repetition Frequency (PRF) The amount of time between successive pulses, or bursts, of electromagnetic energy that is transmitted by a radar. The PRF determines the maximum range at which echoes can be detected and also the maximum radial velocity that can be detected by a Doppler radar. Pulse Repetition Time (PRT) The time elapsed between pulses by the radar. This is also called the pulse interval. Pulse Resolution Volume A discrete radar sampling volume, of dimensions (horizontal beamwidth * vertical beamwidth * 1 range gate). Pulse Severe Thunderstorms Single cell thunderstorms which produce brief periods of severe weather (3/4 inch hail, wind gusts in the excess of 58 miles an hour, or a tornado). Pulse Storm A thunderstorm within which a brief period (pulse) of strong updraft occurs, during and immediately after which the storm produces a short episode of severe weather. These storms generally are not tornado producers, but often produce large hail and/or damaging winds. See also overshooting top. Pulse Width Same as Pulse Length; the linear distance in range occupied by an individual pulse from a radar. h = c * t , where t is the duration of the transmitted pulse, c is the speed of light, h is the length of the pulse in space. Note, in the radar equation, the length h/2 is actually used for calculating pulse volume because we are only interested in signals that arrive back at the radar simultaneously. Pulse-Pair Processing Nickname for the technique of mean velocity estimation by calculation of the signal complex covariance argument. The calculation requires two consecutive pulses, hence "pulse-pair". PVA Positive Vorticity Advection - the advection of higher values of vorticity into an area. PVL Prevail PW Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location, usually extending from the surface to 300 mb. PWAT Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location, usually extending from the surface to 300 mb. PWO Public Severe Weather Outlook --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .