Friday forecast: 100 at BWI, 102 downtown
The National Weather Service has dialed back its predictions for Friday's high temperature at BWI-Marshall Airport - from 102 to a mere 100 degrees. But the high at the Inner Harbor is still forecast to reach 102.
UPDATE, 12:15 p.m.: An Excessive Heat Watch has been posted for Thursday across all of Central and Southern Maryland. Temperatures will be in the upper 90s to 100 degrees, with Heat Index values of 105 to 110 degrees:
"AN EXCESSIVE HEAT WATCH MEANS THAT A PROLONGED PERIOD OF HOT
TEMPERATURES IS EXPECTED. THE COMBINATION OF HOT TEMPERATURES AND
HIGH HUMIDITY WILL COMBINE TO CREATE A DANGEROUS SITUATION IN
WHICH HEAT ILLNESSES ARE POSSIBLE. DRINK PLENTY OF FLUIDS...STAY
IN AN AIR-CONDITIONED ROOM...STAY OUT OF THE SUN...AND CHECK UP
ON RELATIVES AND NEIGHBORS."
Earlier post resumes: We should expect these predictions to fluctuate as the week goes by, and computer models crunch fresh data and regularly spit out new information. A lot depends on how much cloud cover drifts into the region from elsewhere, providing some feeble shade against the July sun. That's pretty difficult to predict with much precision this far out.
Anyway, in the short term, forecasters are predicting some small chances for showers and thunderstorms Tuesday and Wednesday afternoon - in the range of 20 to 40 percent - as storms fire up in the Midwest and ride around the edge of the high and stagger into Maryland's heat and very high humidity.
NWS/Sterling science officer Steve Zubrick told me yesterday that dew points during this period will reach the low 70s, with some near the bay sloshing up to 75 degrees or higher. (see map) Add forecast temperatures of 95 again today, 98 on Thursday, 100 Friday and 99 Saturday, and it's going to be stifling.
Heat Index readings - a measure of the combined effects of heat and humidity on the body's ability to cool itself - are expected to top 110 degrees by the end of the week.
The Baltimore Health Department issued a Code Red Heat Alert today, effective through Sunday. That will open cooling centers across the city and send workers out to check on vulnerable residents.
Ocean City looks better, with a predicted high of only 88 degrees for FRiday, rising to 91 by Sunday. Deep Creek Lake is looking forward to highs of 87 for the entire weekend, with chances for showers every day from now thorugh Sunday.
I remember arriving at BWI once on a day like these, stepping out of the air-conditioned baggage claim area into the heat and humidity en route to the parking lots, and thinking, "This can't be the real air; it's gotta be bus exhaust. Nobody can be expected to breathe this stuff."
Well, it's possible to get a lungful of bus exhaust under there, but it really was the regular air, what Marylanders and visitors alike are expected to breathe in mid-summer. Here's a flower for the grave of whoever invented air conditioning.
(SUN PHOTO: Amy Davis, 2011)