5.25 Evening Zones Update: Transient, unsettled weather continues
Memorial Day Weekend serves, for many, as the unofficial start to summer. Here’s the hoping the atmosphere is thinking the same. So far, Spring has offered mostly transient weather with temperatures near or below average for a fairly notable amount of days. The pattern has been active, as well, with a plethora of storm systems impacting the area over the past few weeks. A few coastal storms have even impacted our region, more typical in the cold season, and have led to raw and rainy days.
While temperatures have warmed gradually over the past few weeks, making the rainy days less damp and cold, the unsettled weather still remains notable across the Northeast. The presence of high latitude blocking and an active Pacific Jetstream have combined to keep it that way, and the active pattern looks likely to remain for the next week or two. In the near term, the weather is likely to remain transient through Memorial Day weekend.
The nature of the weekends transient weather can actually be traced back to a storm system developing today, as a result of a large mid and upper level trough moving from the Central to the Eastern United States. A low pressure system is expected to develop off the East Coast, and move to a position south of Long Island and then east of Southern New England later today and tomorrow. This low pressure will be quite strong for this time of year — down below 996mb on most forecast models.
NAM model showing showers and thunderstorms associated with 996mb low over Long Island later tonight
After rain which moved through the region this morning (related to a warm front) some clearing has occured over parts of Southeast PA and Central and Southern NJ. With a mid level disturbance approaching the region, this extra daytime heating is already fueling to aid in the development of more showers and thunderstorms, just before the sunset. These will move northward back into much of NJ, NYC and CT later tonight — and some of them may be occasionally strong to even severe some gusty winds and hail over Southeast PA and Southern/Central NJ as well.
The low pressure system and upper-level low moves east of New England on Friday, keeping residual unsettled weather over New England for the majority of the day. Meanwhile, west-northwesterly winds will gradually develop in the Northern Mid Atlantic. Another round of more scattered showers and thunderstorms, will likely develop as the atmosphere becomes more unstable with cold-air aloft and daytime surface heating, during Friday afternoon and early evening. The presence of the low pressure system will keep temperatures near or below normal in many areas, particularly New England.
The best day of the weekend looks very likely to be Saturday. Much of the region will be wedged between two larger storm systems — one well to our northeast over New England (moving away) and another developing back to our Southwest over the Mississippi Valley. Temperatures may warm to near or slightly above normal in the lower or middle 70s, especially away from the coast, during the afternoon hours with partly cloudy skies anticipated. However, the pleasant and warm weather may be fleeting quickly, as passing mid-level disturbance will cause some clouds to increase by late in the day and a few showers may return, to parts of the region.
GFS model forecast temperatures for 2pm Saturday afternoon
Largely unsettled weather will again return on Sunday and Memorial Day as a warm front slowly approaches the region from the southwest. While no widespread or heavy rain is anticipated, and timing is uncertain, plenty of clouds and few scattered showers and thunderstorms are anticipated at some point each day. As a result, temperatures may average near to below normal once again in the 60s or lower 70s.
The unsettled weather pattern looks likely to continue into much of next week as multiple storm systems traverse the country and impact the region. Temperatures will likely run near or below normal, each day depend on the amount of clouds and rainfall. If you’re looking for calmer, warmer weather, the forecast looks to take a turn in the positive direction by Mid-June. We’ll have to hang in there until then!