Sure, the sun is shining out there this morning, and it's a pleasant 75 degrees or so. But it's not going to last long.

The National Weather Service radar and satellite data clearly show there's a front with much cooler air behind it, poised on Thursday morning just to our west. It comes out of the Ohio Valley with plenty of clouds. And as it moves across Central Maryland later today, there's a 50 percent chance it will announce itself with some showers and thunderstorms.

Forecasters are calling for less than a tenth of an inch of rain with the frontal passage, or more in thunderstorms. The colder Canadian air behind it could arrive with gusty winds, and small hail. But it will clear off quickly, and then late-afternoon temperatures will begin to drop into the 50s.

Some locations at higher elevations to our west will fall into the upper 30s tonight. "[For t]he first time in several months the words 'patchy frost' have entered my mind," one NWS forecaster said in this morning's forecast discussion. He doesn't really think there will be frost, though. "Still a touch too warm for frost formation," he said.

But, as we've been saying for days, we are looking at some much cooler weather for the weekend, with highs only in the 60s. Next week looks sunny and warmer, with daytime highs at BWI climbing slowly back toward 80 degrees by mid-week.

Meanwhile, out in the Atlantic, Tropical Storm Maria, with top sustained winds at 65 mph, is passing immediately west of Bermuda. A Hurricane Watch and Tropical Storm Warning are posted for the island. Tropical storm winds and 1 to 3 inches of rain are forecast there. The storm could reach hurricane force briefly before weakening in the next few days, the National Hurricane Center said.

UPDATE, 11 a.m.: Maria now has top winds of 70 mph, just below hurricane force. It is now expected to become a hurricane later today. 

UPDATE, 5:30 p.m.: Maria is now a minimal hurricane, with top winds of 75 mph. It is only the third storm this season to reach hurricane strength. A Hurricane Watch and Tropical Storm Warning have been issued for southeastern Newfoundland as Maria accelerates to the north northeast at 36 mph.

There is a "moderate" rip current risk at the beaches. And the weekend at the shore looks problematic, with east winds, clouds and rain chances both days.

Here is the latest advisory on Maria. Here is the forecast discussion. Here is the forecast storm track.