USNA Weather Forecast
Gusty winds overnight and this morning will usher-in a seasonably cool and dry air mass as high pressure builds overhead. The wind gusts will gradually decrease throughout the day as the High builds with clear and nearly calm conditions early Saturday morning allowing the overnight low temperature to dip into the upper 20s.
A Low pressure system will move across the Great Lakes on Saturday and will bring unsettled weather to the region. An associated leading warm front will first push into the Mid-Atlantic region on Saturday morning and intersect the cold (and dry) air mass already in place. A wintry mix will ensue with precipitation types/transition timing dependent on how quickly the surface cold air erodes.
The most probably scenario for Annapolis is light snow Saturday morning with surface air temperatures just below freezing. Initial snowfall radar returns likely will not reach the ground as the precipitation evaporates, moistens the dry atmospheric column, and thermodynamically helps to cool the temperature. Light snow accumulation is possible Saturday morning in Annapolis with coating to 1.0 inch (20% chance no accumulation; 15% chance of 1.0-2.0 inches). By late morning/midday the light snow will likely mix with sleet and/or rain as the surface air temperatures warms and linger near or just above freezing. There could be a midday lull in precipitation intensity, however a period of steady snow/sleet/rain/mix seems probably through the afternoon with some slushy accumulation possible on untreated surfaces (coating to 0.1 inch of sleet/slush possible). By late afternoon/evening, any lingering precipitation in Annapolis will likely be cold rain.
Locations south of Annapolis should anticipate less overall precipitation and fewer wintry impacts. However, locations north and west of I-95 could see 1.0-3.0 inches of snow in the morning followed by a prolonged period of sleet/snow/freezing rain/mix through early evening with 0.1 to 0.25 inches of sleet/ice/slush accumulation, particularly on untreated surfaces.
With numerous dynamic and thermodynamic factors at play, and little consensus in the model guidance, the forecasted precipitation types/transitions could change. Please follow official updates from the National Weather Service at www.weather.gov/lwx. I will also post periodic updates on Facebook. The Low on Saturday will usher-in a pattern change as below normal temperatures are likely through late next week.
Five Day Weather Forecast:
- Friday: Sunny, windy, and cool. Northwest wind 13-18 mph in the morning with gusts as high as 35 mph. Decreasing winds throughout the afternoon. High near 36 oF.
- Saturday: Overcast with light snow possible in the morning (40% chance) and a wintry mix of snow, sleet, and rain in the afternoon (60% chance), and all rain developing in the evening (40% chance). South wind increasing to 8-13 mph. Low: 24-28 oF. High: 36-40 oF.
- Sunday: Sunny and breezy. Northwest wind 13-18 mph, gusting to 32 mph. Low: 38-42↓ oF. High: 40-44↓ oF.
- Monday: Sunny, breezy, and cold. Northwest wind 10-15 mph, gusting to 28 mph. Low: 22-26 oF. High: 30-34 oF.
- Tuesday: Sunny and cold. Northwest wind 10-15 mph. Low: 20-24 oF. High: 30-34 oF.
Five Day Coastal Flooding Forecast:
- There is a chance for minor coastal flooding around high tide at 2347 EST on 18 JAN (water levels 2.4 to 2.7 ft above MLLW possible).
- Otherwise, coastal nuisance flooding is not anticipated.
ISSUED: 17 January 2020 at 0925
NEXT FORECAST: 20 January 2020
FORECASTER: Meteorologist A.R. Davies | Follow on Facebook
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