While yesterday provided many areas with “token relief” from the heat, the next few days should bring the Eastern region the summer’s hottest weather thus far. In fact, the next three days are looking more and more like the three-day period between July 5 and 7 of last year, when the temperature in most of the larger cities reached 100 on at least two of those three days.
During the night, temperatures were no lower than the mid-70s across the region. Temperatures this afternoon will be near 90 at many of the beaches, and the mid or upper-90s in many suburban towns from southern New England to Virginia. However, Baltimore will be close to or slightly above 100. Expect sunshine, and dewpoint temperatures mostly in the lower-70s. The high humidity will make it “feel like” its greater than 100 just about everywhere, but as high as 110 or even 115 in the typically hotter spots. Lows tonight will range from the 70s in most outlying areas to the lower-80s in most of the big cities.
Tomorrow will be the hottest day of the next three. The global models have been consistent in portraying this, and we feel that tomorrow will be the day when we’ll see at least a half-dozen thermometers that will surpass 100 degrees. Of course, we’re referring to those stations which report hourly temperatures. But, it should be implied that most home weather stations and ‘bank thermometers’ will be peaking above 100 degrees as well. When very large high pressure systems set up across the eastern third of the country, we closely monitor what temperature forecasts are (and are forecasted to be) at the 850-millibar level. By early on Friday night, the temperature at the 850-millibar level should be close to 25 degrees Celsius (77 degrees Fahrenheit) at this elevation. It can fluctuate, but is generally around 5,000 feet. Modified soundings, which show the future vertical wind profile of the atmosphere, also indicate that the winds on Friday will be out of the west and northwest from the surface on up to about 5,000 feet. So, it can be implied that most of the unusually warm air aloft will be getting “mixed down” to the surface.
A chart that shows the results of mixing down implies that it has the potential to be as high as 105 degrees Fahrenheit. Dewpoints tomorrow will probably be slightly lower than today, but most of them should still be in the mid and upper-60s. Because there will be some moisture involved, most actual temperatures won’t be as high as 105, but many will still be very close to 100, and it’ll “feel” even hotter.
Be Safe…Stay Cool!!!!