Airmass Persistent SW Date Convection Flow Transient trough Other Notes Prefrontal 3/23/2002 Frontal X Postfrontal Prefrontal 4/15/2002 Frontal X Postfrontal Prefrontal 6/1/2002 X Frontal Postfrontal Prefrontal 9/16/2002 X Frontal Postfrontal Prefrontal 2/1/2003 Frontal X Postfrontal Prefrontal 4/1/2003 X Frontal Postfrontal Prefrontal X 4/2/2003 Frontal X Postfrontal Prefrontal Trough forms to the 9/16/2003 X south Frontal Postfrontal Prefrontal 4/28/2004 Frontal X Postfrontal Prefrontal 5/10/2004 Frontal X Postfrontal Prefrontal 7/9/2004 X Frontal Postfrontal Prefrontal 10/17/2004 X Frontal Postfrontal Prefrontal Arctic 3/13/2005 X Frontal Postfrontal Prefrontal 4/13/2005 Frontal X Postfrontal Prefrontal 5/16/2005 Frontal X Postfrontal Prefrontal 7/22/2005 X Frontal
Date Airmass Convection Persistent SW Flow Transient trough Other Notes 3/23/2002 Prefrontal Frontal X Postfrontal 4/15/2002 Prefrontal Frontal X Postfrontal 6/1/2002 X Prefrontal Frontal Postfrontal 9/16/2002 X Prefrontal Frontal Postfrontal 2/1/2003 Prefrontal Frontal X Postfrontal 4/1/2003 X Prefrontal Frontal Postfrontal 4/2/2003 Prefrontal X Frontal X Postfrontal 9/16/2003 Prefrontal X Trough forms to the south Frontal Postfrontal 4/28/2004 Prefrontal Frontal X Postfrontal 5/10/2004 Prefrontal Frontal X Postfrontal 7/9/2004 X Prefrontal Frontal Postfrontal 10/17/2004 X Prefrontal Frontal Postfrontal 3/13/2005 Prefrontal X Arctic Frontal Postfrontal 4/13/2005 Prefrontal Frontal X Postfrontal 5/16/2005 Prefrontal Frontal X Postfrontal 7/22/2005 X Prefrontal Frontal