Rueter sterling forecast

The high pressure that has been dominating the weather pattern for much of the workweek will begin to shift east into the Atlantic Ocean, bringing more unsettled weather to the Sterling area. Expect temperatures to warm well into the upper 70s tomorrow, with clouds on the increase throughout the day. Southerly flow and strong warm air advection ahead of the cold front will allow temperatures to warm quickly.

Rain will begin Saturday evening and temperatures will cool into the mid-50s as the cold front pushes through the area. A very active pattern looks to be setting up for the weekend and into Monday, The first low pressure center will quickly move up the coast, while a much stronger low pressure center fills in behind by Sunday. This low pressure system becomes strongly negatively tilted by 9Z on Monday and actually retrogrades back south into Pennsylvania as it is vertically stacked. Temperatures will struggle to get out of the 50s as this cut off low pressure center will likely be affecting our area with below average temperatures and potentially heavy amounts of total storm precipitation. The qpf values for 0Z Sunday to 0Z Monday are showing a bulls eye of almost 2.5" of precipitation over the Sterling area. This heavy rain over a period of four days will create conditions favorable for flooding and precautions should be taken.

The real question of this forecast will be the track and location of this cutoff low. The GFS has significantly less precipitation for our area, and the track of the low pressure is much quicker, as it does not retrograde and is far weaker. According to the GFS, the rain will move out of the area by 3Z on Monday, where the NAM has it beginning to retrograde and deepen, with a surface low pressure of 980mb. The ensembles show a good agreement into Wednesday, but the big change with the GFS is more the intensity and precipitation. Since the GFS has not handled cut off lows well at all this year, almost always tracking them through far too quickly, I am definitely more apt to go with the track and precipitation amounts that the NAM has. It makes sense that this cutoff low will deepen and retrograde with the upper level support. Rain should begin for Sterling Saturday afternoon into evening, and continue until early Tuesday. The most intense precipitation will occur on Monday, as the low pressure significantly deepens. Temperatures will be in the mid-50s throughout the whole period after the passage of the cold front Saturday night, and conditions will begin to improve Wednesday and the next ridge pushes in and skies clear.