Weather with Bill Evans

Good Day On This Friday July 30, 2021 A cold front will move through early this morning, followed by a secondary front this afternoon. High pressure will then build from the upper Midwest tonight through Saturday, then weaken Saturday night. Weak low pressure will then pass well to the north across upstate New York and New England on Sunday while another weak low develops along the Mid Atlantic coast and heads out to sea. A cold front will then pass through late Sunday into Monday, followed by a broad high pressure system building in behind the front early next week. The high will shift east and offshore by mid week. A low pressure trough over the Ohio Valley could then bring unsettled conditions for late week. Cold front bisects the area as of 08Z. The front will continue offshore this morning with skies becoming mostly sunny, then a secondary front will move through this afternoon accompanied by bkn Cu. NW winds after passage of this front will pick up to 15-20 mph with gusts up to 30 mph during the late afternoon and early evening. Temps this afternoon via downslope flow and mixing up to 825-850 mb should reach 80-85 in most areas, except upper 70s across the interior lower Hudson Valley. The NW flow will bring in a cooler air for tonight, with lows ranging from the upper 40s in the interior valleys well NW of NYC and in the Long Island Pine Barrens, to the lower 60s in NYC. If winds inland diminish sooner the interior valleys could bottom out in the mid 40s. Fair wx with mostly sunny skies expected on Sat under sfc high pressure. High temps ranging from the mid 70s inland, to upper 70s most elsewhere, perhaps still touching 80 in urban NE NJ. Sat night will also remain dry, with clouds increasing over the interior as a warm front lifts through nrn PA and upstate NY. Return flow will begin to set up along the coast as the sfc high weakens and moves east, so low temps will moderate, ranging from the mid 50s to mid 60s. Clouds should increase daytime Sunday, with chance of showers in the afternoon as weak low pressure passes to the north, and as another weak low takes shape along the Mid Atlantic coast. If the second low tracks close enough to the area, some of these showers could be on the heavy side going into Sunday evening, but this remains uncertain with the ECMWF low track farther south and the NAM perhaps suffering from upstream convective feedback and overdoing the low strength and northward track. High temps should be a touch warmer than those of Sat, mostly upper 70s/lower 80s. The low to the north and associated frontal boundary extending along the Eastern seaboard exits east Sunday night into Monday. Showers and isolated thunderstorms along the front will likely linger in the area into the early morning hours. Expect post- frontal conditions Monday with breezy north winds and clearing skies. Temperatures in the afternoon change little and despite the cold front highs will still be in the upper 70s and low 80s. By Tuesday a 1020mb high pressure system builds behind the front and settles into New York state. Conditions over the forecast area should be stable and with 1000-500mb RH values at or below 50% rain chances are very minimal. Though one feature that will have to be monitored is the previous surface boundary. As it retrogrades northward as a warm front, models are depicting a broad coastal low forming offshore. This low is enhanced an deepened by upper level jet dynamics, but should remain south of the area. Once the high slides offshore mid to late week, south winds from the boundary and warm front continue to moisten the surrounding environment. Southern New York could see precipitable water values around 1.9 to 2.0 inches Thursday. This combined with a mid level trough extending through the Ohio River Valley could lead to a series moderate to heavy rain events late in the week. Much uncertainty remains with the long range forecast and will have to be monitored for updates. .MARINE... Seas on the ocean waters should diminish below 5 ft going into the early daylight hours. A stronger NW flow will then take hold after a secondary cold frontal passage this afternoon. Gusts over 25 kt expected on all waters, with ocean seas building back to 5 ft. Conds should fall below SCA criteria on the non-ocean waters during Fri evening, and on the ocean late Fri night. Quiet thereafter into mid week. Combo of S winds and incoming swell from a low off the coast could build ocean seas back up to 3-5 ft on Wed.