DAYS 1-5 (JULY 26-30)
Summer heat builds in our region over the next few days, but they won’t all be completely similar days. The pattern of air mass changes is actually active during this stretch, and today we’re in a westerly air flow of slightly lower dew point air. It will still be a very warm day with high temps making a run at 90, maybe surpassing it by a little bit in some locations. Absent today will be any rain chance, so other than needing sun protection and hydration, it’s a great outside day (beach, etc.). Things change tonight as the wind shifts to southwest and transports in higher dew points. Some cloudiness may move into the region overnight and around dawn into a part of the morning – debris from upstream thunderstorms later today, limiting any early-day sun, but it will return and heat us up by later morning into the afternoon with more areas reaching or surpassing 90, with a heat index in the middle to upper 90s due to the higher humidity. The concern for Thursday is the later-day thunderstorm threat as a trough of low pressure moves quickly into the region. A couple isolated storms can pop up ahead of what will probably be a broken to solid line of storms to cross much of the region sometime between 3PM and sunset. The potential is there for severe weather to occur – highest threat is damaging wind, but large hail can also occur with stronger cells in the line, and even brief tornado occurrences cannot be rule out. Any activity will sweep off to the east and southeast and dissipate during the evening, and we’ll be left with a quieter but warm and muggy night. But behind this trough we’ll see the wind shift back to the west for Friday, enough to create a down-slope effect (drying of air coming from the hills / mountains to our west). So despite being another hot day, the dew point will fall to the middle and perhaps lower 60s after being around or just over 70 Thursday. But that’s also temporary as we will see a wind shift back to southwest Friday night into Saturday with another shot of higher humidity. How hot it can get Saturday will depend on the timing of a cold front and associated clouds / showers / thunderstorms coming from the northwest. I think the timing will be fast enough that widespread 90+ temperatures can be avoided, but even if it doesn’t get that hot, it will be quite muggy until the front goes by, along with the shower/storm threat. I’ll try to nail down the timing/details next update. Assuming the front is quick enough, Saturday night sees a dew point crash, and Sunday will most certainly be relatively cooler and much drier. Also of note: We’ll see a hazy look to the sky at times the next few days as we still have some areas of wildfire smoke from Canada that the upper winds will transport through the Northeast. Most of if not all of this will be aloft enough not to have an impact on the air quality.
TODAY: Mostly sunny. Highs 84-91, cooler South Coast. Dew point 60+. Wind WSW 5-15 MPH.
TONIGHT: Mostly clear evening. Clouds increase overnight. Lows 65-72. Dew point 60+. Wind WSW up to 10 MPH.
THURSDAY: Intervals of clouds and sun. Showers and thunderstorms likely by mid to late afternoon into evening, and some can be quite strong to severe. Highs 88-95. Dew point 65+. Wind SW 5-15 MPH, higher gusts.
THURSDAY NIGHT: Variably cloudy with showers and thunderstorms diminishing evening. Partly cloudy with patchy ground fog overnight. Lows 68-75. Dew point 65+. Wind W up to 10 MPH.
FRIDAY: Sunny to partly cloudy. Isolated afternoon thunderstorms possible. Highs 89-96, hottest interior valleys, except cooler portions of South Coast. Dew point lowering through the 60s except staying in upper 60s South Coast. Wind W 5-15 MPH in the morning, diminishing slightly in the afternoon when some local coastal sea breezes are possible.
FRIDAY NIGHT: Partly cloudy. Lows 70-77. Dew point rising to 65+. Wind SW up to 10 MPH.
SATURDAY: Variably cloudy. Scattered showers/thunderstorms. Highs 85-92, cooler South Coast. Dew point 65+. Wind SW 5-15 MPH shifting to NW by late.
SATURDAY NIGHT: Clearing. Lows 58-65. Dew point falling to 50s. Wind NW 5-15 MPH.
SUNDAY: Sunny to partly cloudy. Highs 76-83. Dew point below 60. Wind NW 5-15 MPH.
DAYS 6-10 (JULY 31 – AUGUST 4)
Low humidity with fair weather July 31. Higher humidity, no significant heat, and some shower opportunities with a weak through of low pressure moving back into the region in the early days of August. Can refine day-to-day details as it gets closer.
DAYS 11-15 (AUGUST 5-9)
Overall pattern dominated by a weak trough. A shot of drier air from Canada at some point, preceded by shower and thunderstorm chances.