BOX is getting excited
Our weather pattern turns much more active in this period as a strong cold front buoyed by powerful kinematics advances eastward from the Berkshires/Litchfield Hills on into central/eastern MA and RI. Per today`s NWP, the cold front`s eastward advance appears to be slower, as strongly meridional, front-parallel flow contribute to a slower eastward egress. When it comes to projecting impacts regarding this strong frontal passage, timing will be especially critical. Greatest impact likely to be felt by most people include heavy rain, with some potential for urban and poor drainage flooding in slow moving downpours - enhanced by a surge in PWATs of 1.5 to 1.7" per the SREF mean. Potential exists for a few rumbles of thunder as the front marches eastward due to rising dewpoints and the mentioned strong kinematic and dynamic support. These could serve to enhance rainfall rates were any to develop. Today`s guidance swings a fine line of shallow convective elements eastward across the Berkshires and northern CT into central MA by roughly the pre-dawn/early Friday AM commute hrs, with heavy downpours likely to accompany its passage. There are some indications of potential for backbuilding/re- development of northward-moving downpours, which could elevate the risk for localized urban and poor drainage flooding during the morning commute with areas in eastern MA, eastern CT and RI particularly favored. Had considered an impact-based flood watch as this could really cause issues for Friday morning commuters but will let later shifts make that determination with only localized street flooding concerns. Gusty winds and the potential for embedded convection, all capable of producing instances of wind damage, are possible as well. As mentioned previously the low-level jet is maximized near or ahead of the front - 925 mb winds peak around 55 kt across northern CT, much of RI and eastern MA. Mixing however looks shallow and while gusts could reach as high as 40 mph across especially coastal SNE, the questions on mixing made me less confident on gusts into more solid Wind Advisory ranges. However as we tend to see in strongly sheared but weak instability scenarios which best classifies this case, the shallow convective fine line could help mix this down and lead to localized, sporadic instances of wind damage especially as trees are fully leafed. SPC has maintained our area in a general risk for thunder at this point in time; while severe weather is considered a low risk, it is not out of the question to see some wind damage occur in association with this line of shallow convection.
