PM Update: Chance of showers through the evening into Saturday; Which hurricane model should you trust?


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It’s been a warm, muggy, sprinkly day. Light, scattered showers have been moving across the area since this morning, and some of them have become annoyingly persistent, especially just north of the Beltway. Speaking of annoying, dew points are parked in the upper 60s, making for an uncomfortable afternoon. A change is a-comin’ though, and while Saturday still looks like it could be rainy, Sunday will be our turning point back into the better weather we’ve grown so accustomed to this summer.

Through Tonight: Unfortunately it’s going to stay warm and muggy through the evening with lows only reaching 70 degrees by sunrise in the District. The temperature will drop to the mid 60s in the cooler suburbs. Dew points will be in the mid to upper 60s, making the humidity quite uncomfortable. Scattered showers will continue through the evening. Some areas could see locally heavy rain, but widespread heavy downpours are unlikely. 50 percent chance of rain through the night. Winds from the east at 5 to 10 mph.

Tomorrow (Saturday) and tomorrow night: A 30 percent chance of rain on Saturday, though hopefully this won’t bust your weekend outdoor plans. The temperature will climb to near 80 degrees in the afternoon under mostly cloudy skies. It will be a little muggy on Saturday as dew points remain relatively high. The chance for showers continues through Saturday night, as lows bottom out in the mid 60s in the District, and low 60s in our cooler suburbs.

Sunday: Things start to dry out on Sunday under mostly sunny skies. Highs will be around 80 degrees in the city but will only reach the upper 70s in some of the suburbs.  A drop in the dew point will allow for some relief from the humidity. Light winds around 5 mph out of the northeast.

See A. Camden Walker’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter . For related traffic news, check out Dr. Gridlock.

Pollen: Trees and grass are LOW. Weeds are MODERATE. Mold spores are MODERATE.


Nationals Park on August 18, 2014. (Kevin Wolf via Flickr)

Which model should you trust?

This week’s “hurricane hype” discussion here and in social media prompts the question of who to trust. In terms of hurricane models, Jeff Masters at Weather Underground reports each year on the trustworthiness of the various models. On Thursday, he posted on the models’ forecast skill from the 2013 hurricane season. He writes:

As usual, in 2013 the official NHC forecast for Atlantic storms was better than any individual computer models at most forecast time periods, although NOAA’s HWRF model did slightly better than the NHC official forecast for 5-day forecasts. Once again, the European Center (ECMWF) and GFS models were the top performers, when summing up all track forecasts made for all Atlantic named storms. The two models were about equal in performance for 12-hour through 72-hour forecast, with the GFS model besting the European model for 3-day, 4-day, and 5-day forecasts. NOAA’s specialized regional hurricane models, the GFDL and HWRF, were also respectable in accuracy for 12-hour through 48-hour forecast accuracy in 2013, though not quite as good as the GFS and European models. The simple BAMM model and CMC models did quite poorly compared to the others.

Read more on the status of the tropical disturbance in the Atlantic from Brian McNoldy.

Angela Fritz is an atmospheric scientist and The Post's deputy weather editor.
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Angela Fritz · August 22