Premium Weekly Outlook 5/16 – 5/22: Moderation to around average temperatures late week

After some cooler temperatures today and then some more unsettled weather for Tuesday and Wednesday, moderating temperatures to near normal with pleasant weather returns late this week. But there is a potential fly in the ointment for a warming trend to continue this weekend as a coastal storm may try to develop. For this weekly outlook, we’ll discuss some technical details and thoughts on the weather through this week and this coming weekend.

After a very chilly start with temperatures near record lows across the region, temperatures today should be a little warmer than Sunday’s high temperatures with slightly warmer mid-level temperatures, deep mixing and more sunshine in the afternoon. High temperatures should rise into the lower to middle 60s for much of the region today. A tight pressure gradient and winds around 40kts on top of a deep mixed layer will also cause west-northwest winds to gust between 30mph and 40mph again today. The west-northwest winds will also keep sea-breezes from developing this afternoon for coastal locations.

Mostly clear skies are expected for early tonight. Then warm-air advection aloft ahead of an upper-level shortwave trough approaching from the Great Lakes/Ohio Valley will cause more clouds from the southwest to increase later tonight and Tuesday. Temperatures will likely be warmer than Monday with more west-southwest flow and sunshine. A weak cold front dropping south, will may also cause clouds to increase from the north of tomorrow. But any showers from this front likely remain northwest of New York City. Cloud cover will keep high temperatures tomorrow in the lower to middle 60s, which is still below normal. If the onset in clouds is delayed a bit, temperatures could rise into the upper 60s.

Then a couple waves of low pressure running along another frontal boundary stalled south of the region will cause more showers or a period of steady rain to develop over parts of the region later tomorrow afternoon and evening. The most likely areas to see more rainfall tomorrow will be over Central and Southern parts of New Jersey, being closer to the wave tracking to our south. But model guidance shows the region will be at least underneath the right-entrance region of a strong upper-level jet streak to the north tomorrow evening. Then high pressure from over the Great Lakes builds into the area late Tuesday night night with clearing skies. Temperatures will drop into the upper 40s to lower 50s across the much region with northerly winds.

 

High pressure remains in control on Wednesday through Friday with plenty of sunshine and temperatures warmer each day. Deep mixing levels between 700mb and 800mb will help temperatures reach the upper 60s to lower 70s on Wednesday. Then more ridging and warmer mid-level temperatures will likely help temperatures to rise further into the lower to middle 70s for Thursday and Friday. A sea-breeze developing during the afternoon could keep temperatures a little cooler near the coast each day.

Then model guidance shows southern energy coming downstream of the ridge building into Midwest or Great Lakes, then possibly forming into a cut-off low. This will cause surface low pressure developing near the Southeast coast, then tracking slowly northeast. Much of the ensemble guidance keep this low weaker and tracking well south of the region. The lack of high-latitude blocking or Western Atlantic ridging, as well as a large trough over the Western United States, suggests the pattern will be a too progressive for this low strengthen more and track further north, closer to the region.

Weather conditions this weekend and perhaps early next week depend on the outcome of this low pressure system. If this low stays farther south we will have more pleasant weather with temperatures slightly above average. If this low tracks closer to area, more onshore winds, clouds, and some rainfall with cooler temperatures will be in store sometime during the weekend or early next week — especially by Saturday night or Sunday. We will continue to keep a close eye on in it. Stay tuned for more forecast updates during the week.