Cold Air and Another Chance for Winter Weather (12 Feb 16)
POSTED ON: Friday, February 12, 2016 1:17 PM by A.R. Davies
An Arctic cold front will slide across the region Friday night. As it passes, snow showers are possible Friday evening with a coating of snow (up to one inch is possible in isolated locations). Due to the potential impact on the end of the evening rush hour, the National Weather Service issued a Winter Weather Advisory from 1800 EST on Friday to 0000 EST on Saturday.
Behind the front, strong northwesterly winds will usher in an Arctic air mass for the remainder of the weekend. The high temperature on Saturday will only be in the mid 20’s and will likely occur before noon with falling temperatures and single digit wind chill values throughout the day. On Sunday morning, the low temperature will be near 10 oF with wind chill values ranging -5 to -15 oF. Northwest winds will be sustained between 18 and 25 mph throughout the day on Saturday with gusts as high as 40 mph. By Sunday, the wind will gradually decrease with a high temperature in the low 20’s. Wind Chill Advisories will be possible Saturday night and Sunday morning, particularly in some of the Baltimore and Washington suburbs where wind chill values could approach -20 oF.
An area of low pressure will develop along the Gulf States on Monday and will impact the Mid Atlantic area Monday and Tuesday. The National Weather Service categorized our area as having an “Enhanced” winter storm threat between 0700 on Monday and 0700 on Tuesday (an enhanced threat level indicates that the primary threat for this storm is a disruption in travel). At this time, the track of the system up the East coast remains unclear. The Figure below outlines the two most probable scenarios:
Scenario A: The system tracks northwest of Maryland: (75% chance of happening)
If this scenario occurs, expect a period of light or moderate snow to develop on Monday out ahead of the storm (<4.0 inches of potential snow accumulation). As the system tracks north and west of us, a warm front will cross the area from south to north. However, an area of high pressure over New England will help keep some cold air in place at the surface before it retreats out to sea. Therefore, expect the snow to turn to a mix of snow/sleet/freeing rain before turning to heavy rain late Monday night or Tuesday. How quickly the transition from snow to mix to rain will occur under this scenario is unclear at this time. Historically, that transition happens fairly quick south of Baltimore with the worst impacts in terms of icing likely to occur in the valleys east and west of South Mountain and along the Mason Dixon Line. Heavy rain (upwards of 3.0 inches) is possible under this scenario Monday night and Tuesday. This could potentially create flooding concerns.
Scenario B: The system tracks directly over (or just south) of Maryland: (25% chance of happening)
If this scenario occurs, the transition from snow to mix to rain will occur late on Monday/Tuesday morning. This could result in an impactful snow event on Monday (>4.0 inches of potential snow accumulation and perhaps some minor ice accumulation), before eventually mixing to all rain (heavy at times) on Tuesday. This could also mean a significant snow, sleet, and freezing rain event for the suburbs north and west of Baltimore and Washington.
Disclaimer: This is not an official U.S. Navy weather forecast and should not be confused with the official Navy weather forecast provided by the Fleet Weather Center in Norfolk, VA. Furthermore, the official U.S. Government forecast for the greater Annapolis area is issued by the National Weather Service Baltimore/Washington Forecast Office in Sterling, VA.
Category: General Interest