Igor / Front over eastern Newfoundland

21 Sept 2010

GOES VIS series

I inserted a cyan line to denote the front which is discernablein the imagery (when you remove it) and I inserted a grey circle in the area of Igor’s pressure center based on continuityand 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.gifhttp://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. with front)