ELBOW 2001 The Effects of Lake Breezes On Weather Project David Sills, MSC-MRB Peter Taylor, York University Patrick King, MSC-MRB Wayne Hocking, University of Western Ontario Art Schaafsma / Ian Nichols, University of Guelph - Ridgetown College

Motivation - Flash Floods Punkeydoodles Corners flash flooding case from ELBOW lake breeze fronts found to be one of the most important factors

Motivation - Flash Floods Punkeydoodles Corners flash flooding case from ELBOW lake breeze fronts found to be one of the most important factors

Motivation - Flash Floods Punkeydoodles Corners flash flooding case from ELBOW 1997 – 24h precipitation accumulation. Note area of maximum precipitation.

Motivation - Flash Floods

Motivation - Tornadoes Guelph F2 tornado case from 17 July lake breeze fronts important for convective initiation and suspected factor in tornadogenesis

Motivation - Tornadoes

Guelph F2 tornado case from 17 July lake breeze fronts important for convective initiation and suspected factor in tornadogenesis

Motivation - Tornadoes

ELBOW 2001 Objectives To improve our understanding of the way in which low-level boundaries such as lake breeze fronts interact among themselves and with synoptic-scale weather features to initiate or enhance convective storms and generate severe to extreme weather events, including flash floods and tornadoes. To evaluate and improve current methods of short- range forecasting and nowcasting for lake breeze occurrence, location of lake breeze frontal boundaries and circulations, and the initiation and enhancement of thunderstorms and related severe weather at lake breeze fronts.

Investigators (Field program) MSC-MRB (MSC Funding) NRC Twin Otter aircraft time portable 3 cm Doppler radar boundary-layer profiler, radiosondes scientists, computer resources, etc. York University (CFCAS Funding) Mesonet, radiosondes, light aircraft, mobile surveys PDF / graduate students / summer students University of Western Ontario (CFCAS Funding) wind profiler, surface observations, kite observations, radiosondes University of Guelph - Ridgetown College (CFCAS Funding) assistance with mesonet, additional surface data The Weather Network Mobile surveys

Observing Platforms Most instrumention will be sited within the effective Doppler range of the Exeter radar (~100 km radius) Mesonet stations, upper-air launches and aircraft flights will be along lines between Lake Huron and Lake Erie Three simultaneous upper-air releases at 15Z, 18Z and 21Z Aircraft flights at various altitudes to build vertical cross- section through lake breeze circulations and across fronts A 3 cm (X-band) Doppler radar, two profilers, and mobile surface and upper-air observations will be located within the effective clear-air return range of Exeter radar (~50 km radius)

Study Period General Obs:Jan Dec archive operational data for climatological study Enhanced Obs: June Aug data from profilers, radars, mesonet Intensive Obs:11 June - 20 July+ (window) - data from mesonet, upper-air stations, portable Doppler, aircraft, profilers, mobile observations Evaluation, Modelling and Analysis: Aug Dec 2002

Study Location

Instrument Siting

Model Evaluation Will be evaluating the skill of several current operational and semi-operational models to predict lake breezes and associated convective weather eg. HIMAP

MC2 Hi-Res Modelling Will be using the MC2 model to both better understand lake breeze / severe storm dynamics and evaluate MC2’s ability to predict these phenomena

Lake Breeze Forecast Utility The forecaster aid called the Lake Breeze Forecast Utility will also be improved by adding cases from ELBOW 2001.

Summary ELBOW 2001 will build on the experience gained with the 1997 ELBOW pilot project A greater variety of observation platforms will be used including the Exeter Doppler radar, a portable Doppler radar and the Twin Otter aircraft Modelling, analysis and evaluation will be conducted after the field program ends Strong emphasis on knowledge / technology transfer