Johnny Sterling VA
Current visible satellite imagery depicts mostly cloudy skies for Sterling Virginia with a surface temperature of 71 degrees currently being reported with light southerly winds in Washington as of 1744 UTC. Elsewhere upper 60s are being reported with light south winds. These conditions are a result of high pressure moving east into the Atlantic and a surface low located in the Great Lakes pushing towards the area. Radar composite is dry for the entire area.
Short Term (Tonight-Monday)
Models are coming into good agreement on the evolution and development of a deep shortwave trough poised to affect the area during the short term. 12 Z GFS and NAM show warm air advection out ahead of the cold front for tomorrow afternoon with southerly winds bringing in moisture from the Gulf of Mexico. Good omega out ahead of the front along with the other factors mentioned should give good instability for showers and a few rumbles of thunder tomorrow afternoon and evening. As the front crosses Saturday night, winds will turn to the north/northwest bringing in cooler conditions for Sunday as all eyes turn to the shortwave trough in the southern US.
All models GFS/NAM/ECMFW suggest phasing of the northern and southern branch to form a deep low pressure off the Mid-Atlantic coast. The track of the low is still somewhat uncertain between the models. The NAM suggest slower phasing and a low track just off the coast placing much of the region under heavy QPF. The GFS and ECMFW suggest a much stronger solution and a track more inland. This deeper and stronger solution brings even more QPF into the forecast area with precipitation lasting through at least Monday. With that said, models are in agreement in that strong frontogenesis will create an impressive vertically stacked storm system. Needless to say, expect widespread rain to develop across the region Sunday through Monday. Pressure gradient tightens across much of the region so gusty winds will need to be monitored.
Long Term (Monday-Thursday)
Ensembles show agreement on the overall pattern through the extended. Surface low spins into southern New York as the storm becomes negatively titled. As the storm propagates to the north, northerly winds will remain over the area. Thickness levels show 534 over the area with some spotty precipitation around. A rain/snow mix with all snow in the higher terrain is possible. Overall, temperatures will be cool with this stiff north/northwest wind.