Igor / Front over eastern Newfoundland 21 Sept 2010

GOES VIS series I inserted a cyan line to denote the front which is discernable in the imagery (when you remove it) and I inserted a grey circle in the area of Igor’s pressure center based on continuity and clearer area near center Animated gif of satellite: http://www.novaweather.net/Uploads/Igor_2010/GOES_VIS_12_to_18Z_21_SEP_2010_Igor_anim.gif (best to copy into browser window)

Surface Plots

Doppler Radar

Animation of lowest elevation angle http://www.novaweather.net/Uploads/Igor_2010/WTP_Vel_LOLAA_Igor_2010_anim.gif (open in a web browser) Animation of elev 1.5 deg and 3.5 deg available at: http://www.novaweather.net/Uploads/Igor_2010/WTP_PPI1p5_Vel_21_SEP_2010_Igor_anim.gif http://www.novaweather.net/Uploads/Igor_2010/WTP_PPI3p5_Vel_21_SEP_2010_Igor_anim.gif (best copy link into browser I think)

3 elevation angles prior to frontal passage over eastern portion of land

PPI 1.5 degrees

PPI 3.5 degrees

Winds veered to the south as the sharp front approached St John’s (YYT/XSW) and Cape Race (WRA) XSW: 120 at 14Z, 140 at 15Z, 170 at 16Z, 340 at 17Z – sharp shift of almost 180 degrees consistent with sharp front moving west to east, not low center passage moving south to north Airport site YYT had 6-degree temp drop from 16 to 17Z (16C to 10C, 61F to 50F)

Cape Race had similar trend, however data went offline as storm moved by WRA: 120 at 13Z, 130 at 14Z, 180 at 15Z, then offline

High-res Model High-res (2.5km horiz scale) local area model (GEM-LAM2.5) depicted the veering wind ahead of front and passage of absolute center of Igor just offshore

St John’s (XSW/YYT) and Cape Race (WRA) red circles

Model temp and pressure pattern (note kinked pressure pattern assoc Model temp and pressure pattern (note kinked pressure pattern assoc. with front)