D.C. area forecast: From summer heat to autumn crispness in a day

September 12, 2013

Today’s Daily Digit

A somewhat subjective rating of the days weather, on a scale of 1 to 10.

6
Lingering heat thrills summer-seekers today. Autumn lovers start rejoicing tomorrow.

Express Forecast

Today: Morning sun, afternoon clouds. 30% chance of late afternoon storms. Highs: Low 90s.

Tonight: Cloudy, becoming breezy. 40% chance of early-mid evening storms. Lows: Low-to-mid 60s.
Tomorrow: Becoming mostly sunny. Breezy, and much less humid. Highs: Low-to-mid 70s.

FORECAST IN DETAIL

Temperature Map

Temperatures: Latest D.C. area temperature map. See interactive map on our Weather Wall.

The winds of change will be blowing strongly Friday, ushering in a cool, crisp fall preview. But today, we deal with a parting shot from summer, a season that can still pump in heat and humidity well into September.

Showers and storms – some with locally heavy rain and gusty winds – have a 30-40% chance of passing through the region ahead of a strong cold front. This same feature, along with a big blue “H” (high pressure) moving south from Canada, will be responsible for the dramatic cool-down starting tomorrow and lasting through much of the weekend.

Today (Thursday): It will have a summery feel as temperatures easily rise through the 80s and into the low 90s. Mostly sunny skies will aid the warming, though cloud cover will increase after the morning hours.

storm threat

Showers and storms could follow across parts of the region late this afternoon; if storms do occur (30-40% chance), then the timing would favor a window from 5-10 p.m. (earliest across the northwest suburbs and latest across the southeast). Any of the storms could produce heavy rain and gusty winds, but widespread severe weather is not expected. Winds are from the southwest between 5-10 mph. Confidence: Medium

Tonight: A stiffening breeze and plunging humidity levels after midnight will be the highlights, as cloud coverage remains widespread. Showers and storms could linger near the city and points south and east after sunset, but any precipitation will clear out as the cold front drops in during the late evening.

Temperatures will not drop off much given the clouds and strengthening winds, falling into the 60s. Dew points will, however, rapidly falling into the 50s after midnight – setting us up for a comfortable Friday. Winds turn northwesterly and increase to 10-15 mph overnight. Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…


(Caroline Angelo via Flickr)

Tomorrow (Friday): We’ll have a pleasant early kickoff to the weekend, despite all the wind, which will kick up to 25-30 mph in gusts (and average 15-20 mph sustained) from the northwest. Partial cloud cover will scatter during the morning to bring mostly sunny skies for the balance of the day. Temperatures warm into the mid-70s as humidity drops further (dew points into the 40s), making it feel like fall.  Confidence: Medium-High

Tomorrow night: This is when it begins to feel a bit nippy. Bring a jacket with you to the Nats game or one of the county fairs (Anne Arundel, Frederick), as temperatures will drop through the 60s during the evening under a mostly clear sky. Breezes remain brisk through the evening (10-15 mph from the northwest) – adding to the crisp feeling – but slacken off to 5-10 mph as the night progresses. Lows bottom out in the mid-40s in the outlying suburbs (with some lower 40s possible in the highest elevations), upper 40s in the closer-in suburbs, and in the lower 50s downtown. Confidence: Medium-High

A LOOK AHEAD

nice day
Saturday will be a splendid day that feels like late October. Nearly wall-to-wall sunshine and dry, nearly calm conditions take control. Highs only reach the upper 60s to low 70s, which is about 10 degrees cooler than normal. It might be time to drink a mug of hot apple cider after sunset, as temperatures will quickly turn chilly, and eventually dip into the mid-40s in the outlying suburbs and into the upper 40s to near 50 closer to town.. Confidence: Medium-High

Some warmth returns on Sunday, but even as temperatures climb into the mid-upper70s, they will remain cooler than normal.  It remains picturesque outside with sunny blue skies, so enjoy outdoor activities without any weather worries. Humidity increases only marginally, with dew points in the 50s expected. The same goes for Monday, though some scattered clouds may pass through with the approach of another cold front, which could come through the region dry. More significantly, it should knock humidity levels down slightly early next week (though they won’t be that high to begin with). Highs head for the upper 70s. Confidence: Medium-High

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Jason Samenow · September 11, 2013