Laredo Tropical air will remain above south Texas through Thursday afternoon. A much colder airmass will move south from the central Great Plains, bringing quickly falling temperatures and showers when it arrives around 6 pm Thursday in the Laredo area. The much cooler air will take another hour to hour and a half to reach Zapata. Temperatures will recover Saturday, and especially Sunday into Monday before an even colder airmass arrives from Canada Monday evening.
I'm expecting partly cloudy and humid tonight and Thursday, low in the low 70's, high Thursday in the high 80's. Temperatures will quickly fall into the 50's, breezy with rain beginning early Thursday evening, low by Friday dawn in the high 40's. Showers ending, cloudy Friday afternoon, high in the 50's. Partly cloudy Saturday and Sunday, high in the upper 60's Saturday, around 80 Sunday. Partly cloudy Monday, high in the 80's, quickly falling temperatures with showers Monday evening. Cloudy and quite cool Tuesday, high around 50. Partly cloudy Wednesday, high in the 50's.