Wonderful weekend, muggy with showers and thunderstorms early next week

The recent trend of an unsettled work-week, but great weekend will continue, as an area of high pressure has settled into the region, and the previous frontal boundary has finally cleared. This leads to northwest winds, which are much drier in nature, thus the lack of precipitation. However, the trough that caused yesterday’s rainfall is still not too far to our northeast. This leads to cold temperatures in the middle and upper parts of the atmosphere. Once the sun heats the ground, the warm ground combined with the colder temperatures above lead to an unstable atmosphere, causing lift for cumulus clouds. This is why the sun will be peaking in and out of clouds for the rest of this afternoon. The cumulus clouds are well-evidenced by the current satellite. The stronger ones with potential showers are staying to our northeast.

Regardless, the dry atmosphere and high pressures will preclude any precipitation from forming. As high pressure continues to build in and the air gets drier, the cumulus clouds will taper off during the evening. The leftover diminishing clouds combined with temperatures in the mid 70s at the shore should lead to a great evening to view the sunset. Be careful of rip currents, however.

Tonight and Saturday: The decreasing clouds combined with a dry atmosphere will lead to ideal radiational cooling conditions. Some of you may even want a light jacket or sweatshirt tonight, as low temperatures may fall into the low to mid 50s for much of the area, though slightly warmer in the city itself. For tomorrow, the ridge will build in more strongly, leading to fewer clouds and warmer temperatures than we had today. Temperatures should rise into the mid 80s with low humidity and plenty of sunshine, with light winds. At the shore, temperatures will initially climb around 80, but the light winds and warm temperatures will not be able to stop a sea breeze, so winds may get gusty at times, but otherwise a beautiful beach day. Potentially more importantly, the weather will be great as California Chrome goes for his Triple Crown!

Today’s 12z NAM at 500mb valid for tomorrow evening shows a large ridge building into the region. This will lead to a beautiful Saturday and Sunday. Image produced via GEMPAK computer program.

Saturday night and Sunday: Another clear and gorgeous night is on tap for Saturday night, as the ridge of high pressure remains overhead. The light winds and dry conditions will allow temperatures to fall into the 50s, which is great for sleeping. The immediate urban area may only remain in the low 60s. On Sunday, the ridge will continue to be overhead, but now a tad further east — this means that we will be under the influence of some return-flow, allowing the winds to shift southerly. This will not change much in terms of our sensible weather — highs should still be in the mid 80s with sunny skies, and upper 70s along the shore — so another 10/10 day. But the return flow to the south may usher in a bit more moisture as we head towards next week.

Sunday night and Monday: As the ridge continues to move eastward, return flow out of the south and southwest will increase. This will increase our clouds and moisture as the night goes on — thus warmer overnight lows — potentially staying in the 60s, with even the slight risk of a shower. In association with the southerly winds and return flow will be a warm front for Monday, which will further help to increase clouds as well as lift for showers and thunderstorms. The front may get wedged between the ridge to the northeast and an incoming trough to the west — leading to unsettled weather perhaps through Tuesday.

Today’s GFS model valid for Monday afternoon shows high precipitable water values in our area. This means that the whole atmosphere — not just the surface — will be loaded with moisture. This means the potential for — but does not guarantee — heavy downpours on Monday afternoon. (weather.cod.edu)

The high precipitable water values mean that any shower or thunderstorm that forms could produce very heavy downpours. As of now, the instability and wind shear do not appear high enough for much in the way of severe weather, but isolated strong thunderstorms may still be possible. It will not be raining all the time, and there will be some peaks of sun — but the ridge moving to the east as well as a stalled frontal boundary certainly will mean an increase in clouds with the potential for showers and thunderstorms. The duration of the frontal boundary’s stalling will determine whether unsettled weather will last through Wednesday and Thursday, or if we clear out. Temperatures will generally be in the upper 70s and low 80s for next week.