This week will be up and down with a very warm middle. This comes as the pattern remains progressive with low and high pressure quickly traversing the country. This makes it so that neither a high nor low will dominate the week, but will rather continue to trade places.
MONDAY
The system that brought New England's severe weather outbreak yesterday is continuing to drag its cold front across the region. The front's progress will be slow and likely won't clear eastern Maine until Tuesday morning. With this system still around, it will remain generally unsettled for Monday. Frequent showers will be most likely across the northern third of New England as well as much of Maine. A couple isolated showers may drop into southern New England in the afternoon, but most there will remain dry all day today.
GFS showing potential weather this afternoon:
Highs today will vary from around seasonable across central and southern New England, where it will remain mostly to completely dry to cool across the north and into the Berkshires where numerous showers and a thicker cloud cover will prevail. After a warm and humid start to the day, the cold front will keep temperatures from rising too much in the afternoon for everyone. Humidity will also be on the downward trend during the day.
TUESDAY
Tuesday will see the low pressure system and cold front exit eastern Maine. Eastern Maine could see some leftover showers in the morning, but other than that, it will be a dry day with partly cloudy to mostly sunny skies. High pressure will build to the southwest, which will initiate a brief warming trend. A warmer air mass will enter New England aloft, allowing temperatures to get into the 80s region-wide. Humidity won’t return by Tuesday as the flow at the surface remains generally from the west-northwest rather than the southwest.
500mb height change from Monday afternoon to Tuesday afternoon. Rising heights over New England indicate a warmer air mass moving in:
WEDNESDAY & THURSDAY
Wednesday will be the warmest day of the week as a southwest flow firmly takes over ahead of an approaching system and cold front. Temperatures should surge well into the 80s to low 90s for most during the day. New England will once again be placed into the warm sector of the system with a warm front lifting into the region during the day. This will be followed by the system’s cold front, which is looking to cross from Wednesday afternoon to Thursday morning.
As for thunderstorm potential, there will be a chance for stronger storms as the startup is supportive of it, however, the timing of the front may limit severe activity. As of now, guidance is pointing toward pre-frontal showers and storms to break out more toward Wednesday night rather than Wednesday afternoon. This will greatly limit the amount of instability for storms to work with as forcing from the front does not exactly line up with peak afternoon heating.
With that said, some guidance is adamant about a severe weather risk for Wednesday evening. The Storm Prediction Center currently has southern and central New England in the “marginal” category (level 1 of 5) for severe thunderstorms on Wednesday. We’ll need to keep watching trends on the timing of the cold front to get a better idea of this threat.
In any case, Thursday will be cooler and less humid post cold front. With the cold front likely still around, showers may continue to be possible, mainly for Maine, on Thursday. Overall, the day should see improving conditions. Highs will be in the 70s to low 80s.
FRIDAY
On Friday, high pressure will build over New England, bringing continued cooler conditions, but not notably cool, to New England. Highs will likely be dominated by the 70s for most of New England with some low 80s in the valleys of southern New England. With high pressure nearby, the flow will likely be weak, allowing sea breezes to develop, keeping the coast cooler.
Euro showing wind direction and speed on Friday afternoon. You can see the high pressure just to the west of New England st where winds are moving away from the center of the high (winds diverge from high pressure and converge on low pressure):
WEEKEND
The flow remains progressive with the high pressure quickly sliding away ahead of another approaching trough. This trough will bring another chance for showery and potentially thundery weather for next weekend. As of now, the timing looks to favor Sunday for the more unsettled weather over Saturday. Humidity will likely be on the rise once again over the weekend.
Weather map for Sunday morning (June 30):
Comments