A large ridge of high pressure was situated along the eastern seaboard for the week of July 15th through July 19th.  The flow around this high pressure ridge brought a very warm and humid air mass into eastern New York for much of the week, along with plenty of sunshine.
The result was high temperatures each day exceeding 90 degrees.  When combined with the humidity, heat index values exceeded 100 degrees at times during the afternoon and evening hours, mainly for the mid Hudson Valley. The hottest days were July 18th-19th, when high temperatures reached the mid to upper 90s in many locations.  On the 19th, heat index values were between 105 and 110 degrees across portions of Ulster and Dutchess Counties, with heat index values over 100 degrees across much of eastern New York.  The New York State Independent System Operator (NYISO) reported that power consumption reached a record high on Friday, July 19th, exceeding the record set in 2006.
By the weekend, an approaching cold front brought somewhat cooler and less humid air into the region, which allowed heat index values to be lower.

Heat in EASTERN DUTCHESS, NEW YORK
From 17-JUL-13 11:00:00 to 17-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN SCHENECTADY, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ULSTER, NEW YORK
From 17-JUL-13 11:00:00 to 17-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN RENSSELAER, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in NORTHERN WASHINGTON, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHERN WASHINGTON, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN COLUMBIA, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN DUTCHESS, NEW YORK
From 17-JUL-13 11:00:00 to 17-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHEAST WARREN, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHEAST WARREN, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Excessive Heat in EASTERN ULSTER, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in NORTHERN SARATOGA, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ULSTER, NEW YORK
From 15-JUL-13 11:00:00 to 15-JUL-13 18:30:00 (EST-5)
Reported by: COOP Observer

Excessive Heat in EASTERN DUTCHESS, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in NORTHERN SARATOGA, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHERN SARATOGA, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN DUTCHESS, NEW YORK
From 15-JUL-13 11:00:00 to 15-JUL-13 18:30:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHERN SARATOGA, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Excessive Heat in WESTERN DUTCHESS, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN SCHENECTADY, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ALBANY, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN SCHENECTADY, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN DUTCHESS, NEW YORK
From 15-JUL-13 11:00:00 to 15-JUL-13 18:30:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN RENSSELAER, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN COLUMBIA, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN DUTCHESS, NEW YORK
From 16-JUL-13 11:00:00 to 16-JUL-13 15:30:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ALBANY, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN GREENE, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN GREENE, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ULSTER, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN DUTCHESS, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN DUTCHESS, NEW YORK
From 18-JUL-13 12:00:00 to 18-JUL-13 18:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHERN HERKIMER, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in SOUTHERN FULTON, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in SCHOHARIE, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in MONTGOMERY, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN ULSTER, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN GREENE, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN ALBANY, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in EASTERN ULSTER, NEW YORK
From 16-JUL-13 11:00:00 to 16-JUL-13 15:30:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN COLUMBIA, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN RENSSELAER, NEW YORK
From 19-JUL-13 11:00:00 to 19-JUL-13 19:00:00 (EST-5)
Reported by: COOP Observer

Heat in WESTERN DUTCHESS, NEW YORK
From 16-JUL-13 11:00:00 to 16-JUL-13 15:30:00 (EST-5)
Reported by: COOP Observer