 The main focus is investigating the dynamics resulting in synoptically forced training convective rainfall  Synoptic conditions necessary for the generation of an SCEPT event  Define a SCEPT event to which precipitation rate and duration period satisfy a given criteria  Gather selected atmospheric variables which have a statistically significant correlation to SCEPT events  Allow forecasters to better locate regions of training convection based on findings

Synoptically forced Convective Extreme Precipitation Training  Events linked with frontal boundaries (typically warm fronts) ◦ Isentropic lift  Deep convection develops in a baroclinic environment where differential cyclonic vorticity advection is present ◦ Typica lly ahead of a short-wave trough or jet streak  500 hPa trough nearly stationary during training events  LLJ helps initiate convection and heavy rainfall

 Near-neutral to weakly positive differential vorticity advection  Location of 850 hPa maximum moisture convergence  Precipitable water maximum (moisture tongue) good indicator of heavy rainfall  High precipitable water content (>1.42 in) required  Midlatitude and upper-level lows positioned to the W or NW  Strong surface moisture convergence and UVV at 700 hPa

 Multisensor Precipitation Estimates (MPE) using a Z-R relationship to diagnose precipitation rate for each event  SCEPT event location points were gathered from the National Centers for Environmental Prediction – National Center for Atmospheric Research (NCEP – NCAR) while atmospheric variables examined for each event were gathered from the North American Regional Reanalysis (NARR)

 Rainfall rates must be exceeding 17 mm/h for at least 3 consecutive hours to account as an event  Event location determined by where event occurred ◦ If multiple events occurred, location determined by data cluster  NARR data used to analyze synoptic conditions of each event ◦ diagnostic fields included geopotential heights (300, 500, and 850 hPa), 500 hPa differential vorticity, 300 hPa jet streaks, UVV at 700 hPa, 850 hPa temperature fields, and precipitable water

 For each height field, the trough axis either deepening, weakening or neutral and tilted positively, negatively, or neutral  A shortwave (long-wave) trough 8000km) in amplitude and wavelength  Closed lows were recorded at the pressure level(s)  Axis of greatest precipitable water was noted as well  36 SCEPT events during from

1) Closed Upper Level Low (CULL) 2) Upper Level Trough (ULT) 3) 850 hPa Trough-Low (850TL)

 Contained a 500 hPa closed low  Positively tilted & strengthening trough at 850 and 500 hPa  Lows at 300 and 500 hPa nearly stacked  850 hPa jet generally over SCEPT event, moving toward the NW  Precipitable water averaged 36.2mm

 Moisture convergence occurred along the flow of the 850 hPa jet from SW-NE  The SCEPT event was located along the warm front of the associated MLC  Accompanied by WAA  Generally occurred from 7Z -16Z during the cool season months

A) 300 hPa, B) 500 hPa, C) 850 hPa, D) Surface observations

 500 hPa trough without a closed low  Maximum UVV at 700hPa occurred along the flow  850 hPa jet advecting moisture from the SSW  Precipitable water average 37.1mm

 Accompanied by WAA  300 hPa trough located 915 km west of event  Generally occurred in the warm sector of an MLC  Strong, positively tilted troughs existed at 300 and 500 hPa

A) 300 hPa, B) 500 hPa, C) 850 hPa, D) Surface observations

 Weak UL flow with an 850 hPa shortwave trough or low present  Trough/low averaged 565km to west of SCEPT event  Moisture convergence was greatest along flow of 850 hPa jet  Advection occurred from the SSW

 Little to no UL forcing existed and no relationship could be found with the 500 hPa and 300 hPa flows  Precipitable water averaged 42.2mm  Primarily a warm season phenomena

A) 300 hPa, B) 500 hPa, C) 850 hPa, D) Surface observations

 Each case has its own characteristics ◦ However, Strong UVV at 700 hPa, WAA and High Moisture content common to all  Of the 36 events, 47% had a closed 500 hPa low and 25% had a longwave 500 hPa trough ◦ Overall, 72% of the SCEPT events were synoptically forced with a long-wave trough  SCEPT event locations were concentrated across the western region of study ◦ Gulf moisture and Atlantic moisture transport influenced events

 500 hPa trough was slightly positive or neutrally tilted for CULL and ULT events  SCEPT events developed right of the 300 hPa jet streak  Surface moisture convergence maximum within 230 km of event location, training parallel to 850 hPa flow  700 hPa UVV maximums within 270 km of SCEPT event with training at the 700 hPa on a WSW to ENE orientation

 Why SCEPT events occurred during the early morning hours associated with the least thermal instability  Possibility of a weakening LLJ during morning leading to system speed reduction  Longer research period needed examining more variables  Finer look surface moisture convergence and UVV to reduce error