Another rainy end to the week, unsettled pattern extends into 2019

Good morning! Today should start off quite similar to Wednesday, with temps in the upper 20’s and lower 30’s for the morning commute. The aforementioned high pressure system will be moving through southern Canada and portions of New England this morning and into the afternoon hours, which should allow for near-identical conditions as on Wednesday. Temperatures should only be able to rise into the middle to upper 30’s for most of the area, with lower 40s possible for New York City and coastal locations.

While we remain in a relatively cold and dry pattern today a large area of low pressure over the Northern Plains will be dumping heavy snowfall and blizzard conditions in addition to heavy rain and thunderstorms over the Southern Plains. As this system strengthens and heads through the middle of the United States today, the northwesterly flow we’ve had for the past couple of days will shift to a more southwesterly flow. As with the two previous systems that we have seen cut to our west, this means that copious amounts of moisture and warmer temperatures will not be too far behind. The warm front associated with this system does not look to push through the region until after 8-10 pm, meaning any precipitation will likely hold off until later in the night. Light rain showers should be common into the overnight hours with the potential for some light mixed precipitation exclusively for elevated locations well north and west of the NYC area.

~Updated weekly planner~

Any mixed precipitation will quickly change to normal rain very early Friday morning as strong southwesterly flow overspreads the entire Mid-Atlantic and Northeast. Another anonymously moist airmass will be in place just in time for the Friday morning commute, which will likely feature steady rain and winds out of the south. Temperatures on Friday will get rather mild, with highs likely reaching into the lower to middle 50’s for almost the entire forecast area-with a shot at some readings at or around 60 degrees across coastal sections of New Jersey.

Moderate to locally heavy rain will continue throughout the afternoon hours on Friday, with a chance at some localized flooding issues for locations with poor drainage. The rain will gradually tapper off from west to east on Friday evening as the associated cold front lags well off to our west over the Ohio Valley. Temperatures will stay very mild for the overnight hours Friday and into early Saturday morning with lows  in the upper 40’s to middle 50’s (warmer temps will be located to the south and east of the city).

This evenings NAM model showing the progression of moderate rain developing late Thursday night and lasting through much of the day on Friday

Drier conditions over the weekend and more unsettled for New Years Eve

This weekend should start off quite pleasant as the cold front and associated northwesterly flow lagging behind Fridays storm system finally pushes through on Saturday. This will lead to increasingly sunny skies and falling temperatures throughout much of the day, with temps going from the middle to upper 40’s in the morning, to upper to middle 30’s by the afternoon hours. High pressure will also be building back into the East late in the day on Saturday, which will cause low temperatures across the entire area to drop to seasonable levels. Expect lows in the upper 20’s to lower 30’s for the vast majority of the metro area.

By Sunday we’ll likely be watching a weak/strung-out piece of energy that gets left behind over the Southern Plains from the previous system. While yesterday’s afternoons model guidance severely diverges on the ultimate evolution of this system, there is a low possibility that this system is able to organize somewhat during the early morning/afternoon hours on Sunday over the Ohio Valley and produces a very light area of precipitation over portions of the Mid-Atlantic. Due to the very fast flow that will likely be in place over the Northeast and the lack of blocking to allow this system to slow down and significantly organize, this system has a very low ceiling for its potential impacts. In fact, the latest guidance overnight and this morning, has this system much weaker and staying to the south, for these reasons. So we have taken precipitation out of the forecast for Sunday.

Things begin to get more unsettled as we move into New Years eve and New Years day. Wednesday afternoon’s European model showed a large trough digging into the Western half of the country, which would cause another area of low pressure to pass off to our west and likely produce more rain and mild temperatures to close out 2018. Some of model guidance did show this system getting suppressed to our south, which would have increased the chances of seeing some more frozen precipitation. But most models this morning are now showing this system tracking to well to northwest as like the European model. The main point to take away here is that this time period seems increasingly likely to feature unsettled conditions with more rain likely arriving New Years Eve afternoon and night. This system will begin moving away with some clouds and perhaps some spotty showers left behind on New Year’s Day.

This afternoons ECMWF model showing the potential for yet another rainstorm to close out 2018

We’ll continue to monitor both systems over the coming days and we will have an update out by Friday! 

Have a great night!

Steve Copertino