Perfect through the weekend; Fay rain later?
Boy, you can't beat this forecast. From today straight through the weekend, forecasters are calling for sunny to mostly-sunny skies. Afternoon highs will stick close to seasonal norms - in the mid-80s - and the nights will be fine for opening the windows and shutting off the AC.
It looks for now like we're done with the 90-degree beatings we've been taking this week. The backdoor cold front late yesterday dropped temperatures noticeably. After a high over 90 yesterday afternoon, we fell to 52 overnight out on the WeatherDeck. Here are the readings from The Baltimore Sun's weather station at Calvert & Centre streets.
BWI reported a high yesterday of 93 degrees (the fourth 90-plus day this month), and then an overnight low of 62 degrees.
So, are we done with the 90s for the summer? I wouldn't bet the ranch on that. BWI had six days in the 90s in September last year. But then, we had 16 days in the 90s in August of last year, too. And we're not going to come close to that this month.
Thanks largely to a cool August (a degree cooler than the long-term average so far, with 12 of 19 days below the norm), this summer has been generally cooler than the last two. At least so far. Here are the counts of 90-plus days, by month:
2006: May (2); June (6); July (18); August (13); September (0); TOTAL: 39
2007: May (3); June (7); July (10); August (16); September (6); TOTAL: 42
2008: May (0); June (9); July (10); August (4) through the 19th; TOTAL: 23
Now, as for Fay... In their discussion this morning, forecasters at Sterling say that by Sunday, the high pressure system we're under now will begin to move off the coast. That will put us in the return flow, bringing warmer, wetter air up from the South. Humidities will rise, increasing the chance for showers or thunderstorms Sunday night into Monday.
By the middle of the week, moisture from the remains of Tropical Storm Fay could begin to cross our region, bringing rain. But forecasters can't tell yet where or precisely when that would occur.
If it comes, we could use it. BWI is running 1.68 inches below average for the month. Drought monitor data show abnormally dry conditions close by, in Delaware and New Jersey. Streams are low in central Maryland and water tables are falling, although that's not unusual for mid-summer.
On the map below, red and orange dots represent streams flowing at rates in the driest quarter of the archived record.
No emergency, but a good dose of rain would be welcome.