Can we execute workflow to check if condition is met and send an email

This workflow should be possible by using the SmartObject event and executing this SmartObject, then perhaps storing the results in process data fields and using line rules to check if it should proceed with the sending of email or not.

https://help.k2.com/onlinehelp/k2blackpearl/UserGuide/4.7/default.htm#Thick_Client_Wizards/Event_Wizards-General/SmartObject/SmartObject_Event.htm?Highlight=smartobject event

https://help.k2.com/onlinehelp/k2blackpearl/UserGuide/4.7/default.htm#2.Create/K2_for_VisualStudio_K2_Studio/4.Workflow/Object_Browser-3.ProcessActivity_Data.htm?Highlight=data field

https://help.k2.com/onlinehelp/k2blackpearl/UserGuide/4.7/default.htm#2.Create/K2_for_VisualStudio_K2_Studio/4.Workflow/Line_Wizards.htm?Highlight=line rule

https://help.k2.com/onlinehelp/k2blackpearl/UserGuide/4.7/default.htm#Thick_Client_Wizards/Event_Wizards-General/Email/Email_Event.htm?Highlight=email event

You can use the schedules to start workflow each days:

https://help.k2.com/onlinehelp/k2blackpearl/UserGuide/4.7/default.htm#K2_Management_Site/Workflow_Server/Schedules.htm?Highlight=schedule

If not 4.7, perhaps creating Windows Service to run each days to start workflow via code:

https://help.k2.com/onlinehelp/k2blackpearl/DevRef/4.7/default.htm#Start_Instance_and_Get_Data_Fields.html?Highlight=start

Or creating a Windows task that calls an application/console app that starts this workflow via code.