DAYS 1-5 (SEPTEMBER 11-15)
A little more tweaking in the shorter term forecast as details on the weekend trough / low pressure system become more clear. You may remember a few days ago I mentioned this weekend looking great, and all guidance reflected that idea of high pressure in control the entire time with fair weather. But guidance is not always so good, and sometimes it leads us astray, which it did in this case for me. So now we talk about a bit of a split this weekend. But before that, we do have a nice day today with high pressure in control, building in from the west. A ribbon of high clouds provided a nice sunrise if you were up for it, but sunshine will be abundant today along with dry air and a northwesterly breeze. As high pressure moves overhead tonight, winds die off and radiational cooling takes hold. The temperature spread you saw on my previous forecast will definitely not be adequate enough to cover the range in temperature we will see for later tonight to Saturday morning for low temperatures, where the normal colder spots can drop to around 40 while the urban areas can stay at or above 50. The high will still have enough influence so that our weather is fair on Saturday, to start the weekend, but you’ll notice more high to mid level cloudiness starting to show up later on ahead of our next trough – the one initially underestimated by guidance. This system will move through during Sunday. An initial disturbance going by just to our southeast will toss a batch of moisture our way with rain and embedded heavier showers moving through the region Sunday morning to midday from southwest to northeast. This will be followed by a clearing trend and some sunshine should return to the region during the afternoon in the same progression the rain had. You will notice another spike in humidity during Sunday. A cold front still has to move through and will do so later at night with a shower threat. High pressure builds in during Monday and Tuesday with fair weather and lower humidity again. Previously, I had this progression faster and hinted at much warmer weather Tuesday than we will probably end up with, but it will still be on the mild side.
TODAY: High clouds can filter the early-day sun, then brighter sun with just a few passing fair-weather clouds. Highs 71-78. Wind NW 5-15 MPH, a few higher gusts.
TONIGHT: Patchy high clouds but mainly clear. Lows 40-47 valleys, swamps, and bogs, 47-54 elsewhere with mildest in urban centers. Wind NW up to 10 MPH dropping to calm.
SATURDAY: Lots of sun, but more high and middle clouds later. Highs 70-77. Wind variable up to 10 MPH.
SATURDAY NIGHT: Increasing clouds. Fog patches overnight. Rain potential South Coast toward dawn. Lows 55-62. Wind S up to 10 MPH becoming variable.
SUNDAY: Cloudy start with a period of rain in the morning to midday, steadiest and longest-lasting I-95 belt eastward, including embedded heavier showers, as well as patchy fog. Clouds break for sun afternoon. Humid. Highs 70-77. Wind variable becoming SW 5-15 MPH.
SUNDAY NIGHT: Variably cloudy. An additional shower possible. Patchy fog. Lows 56-63. Wind SW up to 10 MPH shifts to NW.
MONDAY: Mostly sunny. Less humid. Highs 71-78. Wind NW 5-15 MPH.
MONDAY NIGHT: Mostly clear. Fog patches in low elevations. Lows 51-58. Wind NW under 10 MPH.
TUESDAY: Sunny. Highs 72-79. Wind variable up to 10 MPH.
DAYS 6-10 (SEPTEMBER 16-20)
Warm, fair weather September 16. Shower chance September 17. Dry, cooler later next week.
DAYS 11-15 (SEPTEMBER 21-25)
Shower chances greatest September 24-25, with fair weather expected leading up to that. Temperatures variable, but not too far from normal. Autumnal equinox is at 8:05 p.m. EDT on September 22.