Steamy Nights in the Big Apple: UPDATE July 20th
Temperatures in New York City bottomed out at 81° on Saturday July 20th, the third consecutive day above 80° and possibly breaking or tying the record for such. On Friday morning (July 19) the minimum fell to just 83° in Central Park (1° short of the all-time record) and 86° at La Guardia Airport (tying their record). Cooler air is now filtering into the region and the heat wave should break on Sunday.
The official Central Park site in Manhattan fell to just 83° Friday morning (July 19th) just short of the all-time warmest low temperature of 84° set on July 22, 2011. At La Guardia Airport in Queens the minimum was 86°, tying their all-time record of 86° also set on August 2, 2006. Bridgeport, Connecticut tied their all-time record low maximum temperature with 80° (previously seen on July 4, 2002). The city is enduring its 7th consecutive day with 90°+ temperatures and 3rd consecutive day with minimum temperatures remaining above 80°. I'm not sure if this is a record for the site but am confident it at least ties such. This has been the first 7-day stretch of 90°+ temperatures since a 9-day stretch August 11-19, 2002. The longest 90°+ period in the city’s history was 12 days from August 24-September 4, 1953. So far this month Central Park has averaged 81.7° (through July 20th) and thus has a shot of besting its warmest single month on record of 81.4° in July 1999. However, cooler air is expected to overrun the region by Sunday and another big heat wave does not appear to be on the horizon at this time, so it is unlikely the 1999 figure will be topped.
Heat indices have hovered around 105° for much of the NYC and Philadelphia area with some 110°s being reported at local amateur weather stations although the official site at Dover, Delaware had a heat index of 110° at their 1 p.m. observation time (93° with 78° dew point: 63% humidity) on July 18th.METARS for New York's Central Park official site as of mid-afternoon Friday July 19th. The minimum of 83° was just 1° short of the warmest low on record of 84° set on July 22, 2011.
NWS-New York City web site.
A large swath of the nation is enduring 90°+ heat this Thursday although no truly extreme temperatures are being reported from anywhere. For the most part the heat wave is fairly typical of what one might expect in mid-July east of the Mississippi River.Temperature map for 5 p.m. EST on July 18th. 90° temperatures stretch from Montana to New Hampsire and southward.
UCAR map.The oppressive heat is being caused by a near-record warm dome of air over the eastern third of the country as seen in this map of 500 mb-level temps. The surface maximum temperatures would be hotter than what we have seen so far if drought conditions rather than flooding rains had preceded the heat wave.
Map from Washington Post Capital Weather Gang.
Christopher C. Burt