Hub of the heat: Washington, D.C. soars to 99, breaking record high

UPDATE, 3:45 p.m.: The mercury touched 99 at 2:34 p.m. according to observers at Reagan National Airport, breaking the record for the date.

From 1:40 p.m.: At 12:49 p.m., Reagan National Airport (DCA) - the official observing location for Washington, D.C. - sizzled to 98 degrees, tying the record high for June 21, shared with 1998 (and some previous years).

This morning’s low at DCA of 78 is also likely set a record for warmest minimum temperature (unless it drops below that prior to midnight). The previous record was 76 set in 2010.

Temperatures at 1:45 p.m. (Weather.com) Washington, D.C. remains among the top destinations for hot temperatures along the East Coast and for the whole country when you factor in humidity.

Heat index values at 1 p.m. (Unisysweather) As I discussed yesterday, the mid-Atlantic and Northeast coincide with the center of an area of high pressure at upper levels - compressing and heating the air. Lower down in the atmosphere, high pressure is situated to the southeast, circulating humid air from the Atlantic and Gulf of Mexico in a clockwise loop passing over this same region.

Records elsewhere

Today

So far today, here are records that have been tied/broken in the East:

Boston: 96 (previous record 95, 1949)

Nantucket: 92 (previous record 84), also new monthly record!

New York City (JFK): 96

Hartford: 96 (tie with 1953)

Burlington: 97 (previous record 95, 1953)

Wednesday

A number of cities, primarily in the Northeast and New England set record highs Wednesday, including:

New York City (JFK): 94 (previous record 93, 1995)

New York City (LaGuardia): 98 (previous record 96, 1953)

Newark: 98 (previous record 97, 1953)

Hartford: 97 (previous record 96, 1995)

Burlington: 95 (previous record 94)