Freeze Warning in Northern Virginia: Timeline, Impacts

PHOTOS: Patch archive and National Weather Service map; area in deep purple is under a Freeze Warning; area in light blue is under a Freeze Watch. To see the map legend, go to NWS.

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While the DC metro area is more than two weeks into official spring, Mother Nature has other plans.

The National Weather Service on Monday issued a Freeze Warning for most of Northern Virginia and Washington, D.C. The areas under the warning include the District of Columbia, Arlington, Fairfax, Loudoun and Prince William counties as well as the cities of Alexandria, Fairfax, Leesburg, Manassas and Manassas Park.

A Freeze Warning means sub-freezing temperatures are expected. The Freeze Warning goes into effect Monday night, at midnight, until 10 a.m. Tuesday. Expect temperatures in the upper 20s to lower 30s Monday night and Tuesday morning and mid-20s to around 30 degrees Tuesday night, the weather service said.

Here's a look at Monday's weather rollercoaster, from the NWS forecast for the DC metro area:

• Monday: Showers and possibly a thunderstorm, mainly after 2 p.m. High near 69. Southwest wind 13 to 18 mph, with gusts as high as 33 mph. Chance of precipitation is 80 percent. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
• Monday night: Showers likely and possibly a thunderstorm before 11 p.m., then isolated showers between 11 p.m. and 2 a.m. Cloudy during the early evening, then gradual clearing, with a low around 31. Blustery, with a north wind 15 to 20 mph, with gusts as high as 33 mph. Chance of precipitation is 60 percent. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
• Tuesday: Sunny, with a high near 47. North wind 11 to 16 mph, with gusts as high as 28 mph.

Northern Virginia is also under a Freeze Watch late Tuesday night through Wednesday morning.

How to protect your plants

Unprotected vegetation sensitive to freezing temperatures will be killed or damaged, the weather service warns.

Here are some steps you can take when a frost or freeze threatens, according to TodaysHomeowner.com.

• Bring Indoors:Frost-tender plants in containers should be brought inside during cold weather. Dig up tender bulbs and store them in a cool dry place.
• Water Plants: Water plants thoroughly before a freeze to prevent desiccation and to add insulating water to the soil and plant cells.
• Protect Tender Sprouts: Cover tender plants overnight with an inverted bucket or flower pot, or with a layer of mulch. Be sure to uncover them in the morning when the temperature rises above freezing.
• Cover Shrubs and Trees: Larger plants can be covered with fabric, old bed sheets, burlap, or commercial frost cloths (avoid using plastic). For best results, drape the cover over a frame to keep it from touching the foliage. Fabric covers help to trap heat from the soil, so make sure your cover drapes to the ground. Uncover them in the morning when the temperature rises above freezing.
• Assess Losses:Hardy perennials, trees, and shrubs may recover from a late spring freeze, even if visibly damaged. Their blooms and fruit may be lost for the year, but once they begin actively growing you’ll be able to determine and remove any permanent damage to stems and branches. Frost-tender plants will not recover at all, so avoid planting them until you’re confident that freezing weather has passed.
• Practice Prevention: Choose plants that are hardy for your climate zone, or plant tender plants in containers that can be brought indoors. Avoid applying fertilizer until after the last frost, to prevent a flush of tender growth that can be damaged by the cold.