Plain-language summary:
Some scattered showers will occur from Vermont westward today before dying down tonight. Widespread light rain moves into the region from Monday night through Tuesday evening, with rain possibly lasting through Wednesday. It will likely turn sunnier, warmer, and drier for Thursday and Friday before more wet weather is possible late next weekend. It turns really uncertain afterward, but it likely will turn warmer for at least a day or two before possibly turning cooler and more showery again for a few days before turning warmer again afterwards. The cooler temperatures will be primarily be during daytime, with clouds and moisture preventing nighttime frosts and freezes.
Meteorological discussion:
A weakening upper-level low passing to the south will produce some scattered showers today, mostly from Vermont on westward. The showers will be a little more convective and stronger but hit or miss during the day today, as breaks of sun lead to surface heating and also instability given the cool air aloft. Showers will die down tonight as the upper-level low weakens and we lose the daytime instability. Another low pressure will move into James Bay tomorrow, with warm advection induced widespread light rain overspreading eastern Ontario and northern New York by early afternoon, and then southern Quebec and the rest of northern New England tomorrow evening, except Maine which could miss this first round of rain. The low pressure will move into central Quebec and weaken, but an extended area of surface troughing extending from Quebec down to a slowly strengthening low pressure in Missouri will lead to another round of rain Monday night into Tuesday evening for most. The low pressure in Missouri will move onto the southern New England coast by Wednesday, producing more rain from northern New York to central Maine, but areas north of the U.S./Canada border will likely be dry on Wednesday. However, since it is a slow-moving and somewhat cut-off low, the timing and location is a bit uncertain. Northerly flow behind the storm could lead to a brief cooldown, though the air mass coming in is not that cold, and the increased sunshine and drier air could actually lead to warmer surface temperatures during daytime north of the rain area.
 |
| Source: TropicalTidbits |
 |
| Source: TropicalTidbits |
The slightly cut-off low pressure will only slowly move eastward through Thursday while slowly weakening. Clouds and precipitation will gradually diminish Wednesday night into Thursday. Somewhat higher pressure should lead to a warmer and drier Thursday and Friday with more sunshine. However, the outlook then becomes really uncertain with the slow-moving nature of systems. With the strong May sun angle, it will turn warm, perhaps the warmest of the spring so far, as the air mass that wasn't that cold to begin with warms considerably. Another perhaps weaker storm approaching from the central Plains will likely lead to more rain next weekend, though it might also be slower or get buried to the south, in which case at least Saturday would be dry in most of the region and still rather warm. Next Sunday will likely be wet with slightly cool temperatures.
 |