DAYS 1-5 (JULY 1-5)
This 5-day forecast period takes us through the holiday weekend as Independence Day is Saturday. July starts off with a spell of hot weather as an upper ridge builds in, though its center remains to our west, delivering heat from the Midwest and Great Lakes, while high pressure at the surface builds to our south, sending in higher humidity behind yesterday’s disturbance and warm frontal passage (which was responsible for some heavy downpours in parts of the region). Being on the eastern side of the “ring of fire” – the zone where thunderstorms can travel around the periphery of the high pressure ridge, we’ll have to watch for those, aided of course by the heat and humidity. Our chances are highest today through early Thursday morning, before they drop off during the day Thursday and through much of Friday when the ridge reaches its most eastward extent. As the ridge backs to the west a little and allows a cold front to drop through the region Saturday, we’ll again face a higher thunderstorm possibility. While this pattern supports high heat and humidity in general over this period of time, there are also modifying factors. They include: Local sea breezes, debris cloudiness from thunderstorm clusters, actual storms with heavy rain, and post-storm cooled air. These can all at least temporarily slow down or take the edge of the heat. It’s also not going to be across the board oppressive humidity the entire time for most areas either. We will see some dew points break the 70-degree mark, but many areas may stay in the 60s for dew points for many hours, and also a westerly wind can occur and create a down-slope effect which can drive down points even lower, especially in the coastal plain. Sometimes when this happens, however, the air temperature can end up higher, but the breeze and lower dew point can compensate for this. Additionally, you may have heard talk of “low temps in the 80s”. That will not be happening either. The closest we will come to that a night or two is a low temperature closer to 80 than to 70 in some of the urban centers, due to the “heat island” effect, most certainly not where the extreme majority of people are trying to sleep. So it’s very important to keep all of this stuff in its proper perspective, which I will for you. So, despite headlines you may have seen, this will not be “the hottest (or the worst) in years”. It will be a hot spell in July, the likes of which we’ve seen many times. Now that we have that cleared up, how about the rest of the outlook heading through the weekend? Well, Saturday is key obviously, since it’s Independence Day, and currently I am leaning toward an earlier-in-the-day frontal passage over a later one. A later one would mean hotter weather and a longer / later chance for showers and t-storms, while earlier could easily cap the temperature rise but also end the shower and storm threat much sooner. Additionally, you may have heard some talk about a front that doesn’t really make it through the region. I also disagree with that idea and believe the front moves through efficiently enough so that we see drier and “cooler” (80s) on Sunday with fair weather, courtesy of high pressure to our north.
TODAY: Variably cloudy morning-midday with a shower or thunderstorm possible. Partly to mostly sunny afternoon with isolated thunderstorms possible. Highs 89-96. Dew point 65+ Wind SW 5-15 MPH, gusts around 20 MPH.
TONIGHT: Partly to mostly cloudy. A passing shower or thunderstorm possible. Lows 67-74. Dewpoint 65+. Wind SW 5-15 MPH.
THURSDAY: Early clouds, then lots of sun. Only a remote chance of an isolated thunderstorm. Highs 93-100 except 85-92 South Coast. Dew point 65+ but may drop to 55-62 in the coastal plain. Wind W 5-15 MPH, gusts around 20 MPH.
THURSDAY NIGHT: Mostly clear to partly cloudy. Lows 71-78. Dew point 65+ but may start out below that in some areas. Wind W to SW 5-15 MPH.
FRIDAY: Plenty of sun. A few clouds. A remote chance of a thunderstorm. Highs 92-99 except 84-91 Cape Cod. Dew most mostly 65+ but can fall again in coastal plain. Wind SW to W 5-15 MPH, a few higher gusts.
FRIDAY NIGHT: Partly cloudy. Lows 71-78. Dew point 65+. Wind SW 5-15 MPH.
SATURDAY (INDEPENDENCE DAY): Variably cloudy. Chance of showers and thunderstorms especially morning-midday. Highs 85-92. Dew point 65+ then lowering. Wind SW shifting to N 5-15 MPH, higher gusts possible near any storms.
SATURDAY NIGHT: Partly cloudy to mostly clear. Lows 65-72. Dew point falls below 60 late. Wind N 5-15 MPH.
SUNDAY: Mostly sunny to partly cloudy. Highs 81-88, coolest coastal areas. Dew point sub-60. Wind NE 5-15 MPH.
DAYS 6-10 (JULY 6-10)
Greatest chance of unsettled weather July 7-8 and again July 10. Overall pattern is less hot with high pressure to our north and a frontal boundary to our south. Details TBD.
DAYS 11-15 (JULY 11-15)
Overall pattern features west to east flow with a few passing disturbances bringing shower and t-storm opportunities, but no prolonged unsettled weather. Temperatures near to above normal with the return of some hotter weather possible.