10:40 p.m. update: After reviewing the latest models, no changes required to the forecast below. I still think this event is a bigger deal west of I-95 and especially into Loudoun and Frederick counties, where temperatures will be colder and ice lasts longer. We’ll have coverage starting at 5 a.m.
Today we broke a 63-hour streak of temperatures at or below freezing, as highs reached 35-40 degrees. We’re transitioning to even milder weather but we must first endure a period of mixed precipitation early Friday, that may cause mischief for the morning commute.
Through Tonight: Mostly cloudy into the pre-dawn hours (sorry, no northern lights). Precipitation likely develops between 4 and 8 a.m. – first in areas to the southwest. If it starts early enough, it may briefly falls as sleet and/or snow north and northwest of town (a dusting maybe), otherwise expect light freezing rain. Lows range from the mid-20s in the colder suburbs to the low 30s downtown. The chance of precipitation ranges from 40 to 60 percent, from northeast to southwest. As the ground is cold, please use caution, especially on sidewalks and untreated roads.
Tomorrow (Friday): Light freezing rain is likely (60 percent chance area-wide, so not guaranteed) early on – coinciding with the start of the morning commute. Temperatures should range from the upper 20s to low 30s at that time. As the morning wears on, the entire region gradually warms above freezing – so any ice turns to plain rain. By 8 or 9 a.m., most locations along and east of I-95 should be at or above freezing, and by 9 or 10 a.m., most other places. The exception might be some of the colder pockets in Loudoun and Frederick county which could take into the early afternoon to cross the 32-degree threshold.
Friday afternoon remains cloudy, with periods of light rain. Highs range from the raw upper 30s to low 40s. Winds are light.
Cold wave in perspective – less impressive than January 2009: CWG’s Justin Grieser posted this observation on our Facebook page…
Worth pointing out that the January 2009 cold snap was notably longer than what we saw this week. Temperatures at National Airport remained at or below freezing for 104 consecutive hours (more than 4 days) from Jan 14-18, 2009. For 42 straight hours, it was below 20ºF, with the temperature bottoming out at 8ºF on Jan 17.
This week, by comparison, brought 63 consecutive hours at or below freezing and only 18-19 straight hours below 20ºF. DC’s lowest reading was 6ºF. While this week’s cold was notable for the rapid temperature drop and harsher wind chills, I personally didn’t find it as impressive in persistence. Calling it the coldest in two decades was certainly true for many parts of the Midwest, but not so much D.C.
White House #WeTheGeeks Google Hangout on polar vortex: Tomorrow, I’ll join an esteemed panel to discuss the polar vortex, extreme weather and possible connections with climate change in a live, online Google Hangout convened by the White House at 2 p.m. More information here, on the White House blog: We the Geeks: “Polar Vortex” and Extreme Weather
Washington’s Manic Weather: Behind the Extremes with the Capital Weather Gang: On January 28, Kevin Ambrose and I will giving a two-hour multimedia presentation at the Smithsonian on extreme weather in Washington, D.C. I’ll discuss some of our extreme weather events in recent years and what was behind them. Kevin will complement my presentation with his incredible photos and story telling. The program coincides with the anniversary of the record Knickerbocker snowstorm, which Kevin will also discuss. Follow this link for more information and to register: Weather Gang at the Smithsonian