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Quick-Hitting Snowstorm Likely for Portions of the Northeast Saturday Night

Good evening!

Today has been yet another in a string of warmer and unsettled days across the Northeast, with light to moderate rainfall training over portions of the Mid Atlantic and Northeast. Today’s rain was part of the same strung-out and progressive upper level energy that was responsible for the heavy rain and flash flooding that occurred over portions of the Ohio Valley and Mid Atlantic states last evening. The heavy rains last evenings moved quickly along a frontal boundary that remained stationary over the same areas, causing showers and even some embedded thunderstorms to train over the same locations. While the vast majority of these showers and thunderstorms very quite weak in nature, there were some stronger storms over the Ohio Valley and Northeast that produced some damaging wind gusts, along with an EF-1 tornado just to the south and east of Pittsburgh. Regardless, today was a rather dreary day across the entire region as the mid level energy over the Ohio Valley quickly moved east and caused numerous showers to break out once again. The showers have since moved offshore as the majority of the mid level energy moves off to our east, leaving behind mostly cloudy conditions. Despite the mostly cloudy and rainy conditions today, temperatures were able to rise to above-normal levels once again across the Northeast. Readings varied from the lower to middle 50’s over the New York metro area, to middle 50’s to lower 60’s across portions of southern New Jersey. These mild conditions should last until the late evening hours as a cold front begins to approach the area from the west, bringing in cooler temperatures overnight along with Northwesterly winds. High pressure will begin to build in over the Northeast tonight, with lows likely falling quite a bit into the middle to upper 20’s over the majority of the area, with lower 20’s expected to the North and West of the city. Calm conditions will likely prevail through the overnight hours as the high pressure expands over the Northeast.

This evenings latest high restitution water vapor satellite imagery along with regional radar mosaic and surface temperatures from across the area. Note the clearer and more dry air over portions of northern PA and NY.

This evenings latest high restitution water vapor satellite imagery along with regional radar mosaic and surface temperatures from across the area. Note the clearer and more dry air over portions of northern PA and NY.

Quick-Hitting Snowstorm Likely Tomorrow Across Portions of the Northeast

Well, with the way this week has went the last thing you would expect is a snowstorm for this weekend, but that is exactly what looks to be shaping up for portions of the Mid Atlantic and Northeast tomorrow night into Sunday morning. A weak a relatively disorganized area of mid level energy will become trapped in the fast-moving west-to-east flow over the CONUS tomorrow morning and begin to race towards the East. As it reaches the Great Lakes region tomorrow afternoon, it will begin to meet up with some energy from the sub-tropical jet over the Southern Plains states, and this will likely cause numerous showers and some localized thunderstorms to develop over portions of the Tennessee valley. At the same time, the area of high pressure that will be over the region this evening will be moving off of the coast, leaving some stale cold air over the region.  Winds will begin to shift to the south over the Mid Atlantic and Northeast, bringing in a slightly warmer low level airmass for tomorrows highs, but overall temperatures look to stay in the middle to upper 30’s. As we get deeper into the evening hours tomorrow, we should see the shortwave trough associated with tomorrows potential storm begin to amplify or strengthen a bit as the ridging over the southeast and western Atlantic causes the system to buckle.

This afternoons NAM model showing the potential evolution of tomorrows snowstorm

This afternoons NAM model showing the potential evolution of tomorrows snowstorm

As the mid level energy begins to strengthen tomorrow evening, we will also see the upper level jet streak associated with this system begin to expand, allowing precipitation to break out farther north into portions of the Mid Atlantic by sunset. Surface low pressure should then begin to develop over the Mid Atlantic coast tomorrow night, with snow quickly expanding from southwest to northeast over the Northeast. This afternoons model guidance still shows a reasonable amount of uncertainty with the strength of this system, which will be crucial to this forecast. Depending on how deep this low gets will determine how much dynamic cooling will take place as the precipitation is falling. A weaker storm will be warmer at the surface with less precip, and therefore less snow. A stronger system will be able to overcome marginal surface temperatures and have increased snowfall rates, yielding higher snow totals. At this time, a healthy compromise of the two seems plausible. Precipitation may start off as a mix of snow and rain over southern portions of the Northeast, but should turn to all snow by 8-10pm or so with the exception of immediate coastal areas.  The snow will quickly become moderate to heavy over portions of Pennsylvania, New Jersey and New York, with an enhanced chance at mixing over Long Island due to easterly winds. Moderate to heavy snow should continue through the overnight hours, likely until 3-5am as the system quickly accelerates to the north and east and moves offshore. Totals will likely vary by location and elevation over the region, but right now we expect a general 3-6″ from southeastern PA through northern NJ, and into SNY and CT. Portions of Long Island may see less than shown here due to prolonged periods of mixing. Travel conditions will likely be quite hazardous if you plan on driving tomorrow evening, so please stay up to the date with your local NWS for any watches or warnings in your area!

Our latest storm total snowfall map

Our latest storm total snowfall map

We will have updates tomorrow on this system including a new snowfall map!

Have a great weekend!

Steve Copertino

Weekend of Unsettled Conditions and Temperature Swings, Potential Cool Shot Next Week?

Good Evening! 

Today has has been a rather decent end to the work week with above-normal temperatures and light winds from the east. A warm front moved through the region the other night and introduced much warmer temperatures and higher dewpoints across much of the Northeast. This increased moisture from the southwesterly flow also allowed for more clouds to develop as well, but this did not stop highs from reaching into the middle 60’s to middle 70’s, which is a good deal above normal for this time of year. However, changes are on the way this evening, with a cold front currently located moving through central Pennsylvania. While this cold front isn’t all that strong, it will be strong enough to drop temperatures later tonight as well as knock dew points down to more seasonable levels. Additional, high pressure will begin to build in behind this front, so this will set up a strong enough pressure-gradient to create some gusty winds in the 15-25 mph range late tonight and into early tomorrow morning. Temperatures should be able to drop into the lower to middle 40’s tonight, with locations more north and west of the city likely seeing lows in the middle to upper 30’s. while conditions would otherwise be quite favorable for radiational cooling and some frost, the potential for gusty winds across the area should limit both of those possibilities.

High resolution visible satellite imagery, surface observations, and regional radar mosaic (Courtesy of SimuAWIPS)

High resolution visible satellite imagery, surface observations, and regional radar mosaic (Courtesy of SimuAWIPS)

Saturday Into Sunday

Saturday should have a nice and crisp start to the day as the northwesterly flow from Canada kicks in over the Northeast with winds still gusting in the 15-20 mph range. High pressure will also continue to build over the area, which should help promote sunnier skies and calm weather during the first half of the day. As we move deeper into the day tomorrow, winds should gradually shift from northerly to easterly, which will signify the start of another warm from passage. Dewpoints will also begin to increase once again as marine air works its way west, which will also work to gradually increase clouds by the late afternoon hours. Highs will likely reach the middle to upper 50’s tomorrow, with some locations closer to the coast likely making it to the 60’s. As the warm front begins to work its way inland, some weak low level energy will be present, which may help to increase the threat of showers across the area. These conditions should last into the evening hours, with lows staying in the middle to upper 40’s-some locations closer to the coast will likely be stuck in the 50’s due to warmer marine air aloft.

Sunday should start off quite the opposite of how Saturday did, as an approaching mid level warm front will increase moisture and available lift. This will cause an increased threat for showers, especially across western New Jersey and portions of eastern Pennsylvania. The overall progression of the front is still in question, but Sunday certainly looks to be quite a few degrees warmer than the previous day, with highs making it up into the middle to upper 60’s, which will be above average once again despite the increased threat for showers and cloudiness. Lows will likely stay rather mild with temperatures dipping into the upper 40’s and lower 50’s.

This afternoons high resolution NAM model showing showers located over eastern PA and potions of NJ early Sunday morning

This afternoons high resolution NAM model showing showers located over eastern PA and potions of NJ early Sunday morning

A Look Into Next Week

By Monday, most of the Northeast should be well within the warm sector of the warm front, so expect warmer temperatures once again for the region, with 70’s quite likely-which will be a good deal above normal. Later in the day on Monday, an area of energy associated with a trough in southern Canada will be moving our area and will enhance southwesterly flow ahead of an approaching cold front. While this front will be weakening quite a bit from when it moves on in from the Ohio Valley, it certainly will have the potential to bring some showers later in the day as it approaches the coast. As the front pushes offshore by Monday evening, dry northwesterly winds will once again take over and provide a chillier airmass for the entire Northeast as Canadian high pressure builds in.

Conditions will then turn rather zonal from Tuesday until Thursday, with the jetstream generally blowing from west to east across the nation. This should allow the area of high pressure to stick around for a majority of the week, with mainly dry conditions expected over the region. Temperatures should generally stay near-normal during this period as cooler air from Canada bleeds south ever-so-slightly. Thursday may have a shot at rather cold lows as an approaching trough from Canada starts to move southward.

By Friday, things begin to get interesting as the models have been keying in on a deep trough moving in over the East and bringing a nice shot of unseasonably cold weather. Western ridging will improve just enough to allow the cold that has been trapped to our north to quickly come down south by Friday night in the form of an arctic front, which will likely drop lows below freezing across the entire zone, with some locations well off to the north and west seeing lows in the 20’s and even teens. Depending on how much low level moisture hangs around before this Arctic front moves through, some locations could actually see flurries or snow showers, but this is something that we will have to revisit next week. Regardless, the chances of a widespread freeze are increasing for the later part of next week.

This afternoons ECMWF model showing a sharp shot of cooler temperatures over the Northeast by the end of next week

This afternoons ECMWF model showing a sharp shot of cooler temperatures over the Northeast by the end of next week

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Have a great night!

Steve Copertino

Public Analysis: Beautiful Presidents Day Weekend, Unsettled Next Week

After very blustery conditions with harsh windchills the past few days, we’re on tap for a beautiful Presidents Day weekend with clear and dry conditions expected over the entire region

Despite temperatures in the upper 30’s to low 40’s across most of the area this afternoon, the winds that have been present over the past two days due to the large area of low pressure was located to our east has finally moved on. This has allowed the winds to calm significantly and eliminated any real windchills from the area, making for seasonable conditions. This afternoons visible satellite imagery shows very little in the way of any cloud cover as a weak area of high pressure centered near Buffalo, New York remains in control throughout the rest of the day. This  should provide a very nice close to the work week with only high clouds possible towards sunset. Later this afternoon and this evening, a warm front located to our south will begin to move to the north and overspread the area by tomorrow morning. This front should initially usher in some mid-level clouds tomorrow morning, but these should be short-lived as tomorrow afternoon should be an excellent day for outdoor activities as the clouds burn off and the entire area sees temperatures climb well into the 50’s for the NYC metro and NE NJ, while locations closer to the coast remain limited to the upper 40’s and low 50’s. It is also quite likely that given the amount of warm air advecting into the region on Saturday, that portions of Central and Southern New Jersey reach temperatures at or above 60 degrees! This airmass is quite unseasonable for this time of year and most of the area will be running 10-18 degrees above normal on Saturday.

Visible satellite imagery of the Northeast showing relatively calm conditions and little in the way of cloud cover (Courtesy of Simuawips.com)

Visible satellite imagery of the Northeast showing relatively calm conditions and little in the way of cloud cover (Courtesy of Simuawips.com)

Some high clouds are possible Saturday evening as yet another series of weak mid-level disturbances pass to our north as well the south, but Sunday is shaping up to be very similar to Saturday with yet another beautiful day in store. Temperatures in the immediate New York metro area should be able to reach well into the 50’s, with southern locations once again seeing temperatures 10-20 degrees above normal as they climb into the low 60’s by late afternoon on Sunday. As we progress later into the day Sunday, a backdoor cold front will swing through the northern sections of our area and begin to usher in a more seasonable airmass as winds begin to shift from the south, to a more west/northwest. As this front continues on, we can expect a cooler day for Presidents Day Monday with a sharp temperature gradient from north to south across the area, with southern locations remaining in the low 50’s and 40’s for the northern locations. Overall, Presidents Day should be cooler than this weekend, but should remain dry and with very little cloud cover as a high pressure system from southern Canada begins to build south over the area providing continued calm/dry conditions once again.

Afternoon European model showing temperatures on Sunday reaching 18-25 degrees above normal for the entire area (Valid 1pm Sunday)

Afternoon European model showing temperatures on Sunday reaching 18-25 degrees above normal for the entire area (Valid 1pm Sunday)

As we continue on into the work week next week, mid level ridging will increase once more so a return to above-normal temperatures is likely over the entire Northeast. As a series of mid to upper level disturbances work their way east from the very active Pacific jetstream, we can expected our first shot of rain on Wednesday with a more significant signal for precipitation showing up just in time for next weekend as a stronger system works it’s way into the central part of the country. While we’re currently in a period of unseasonable warmth, the potential does exist for a return to colder temperatures and a more active weather pattern later this month and into the first few weeks of March. Make sure to stay tuned for any and all updates over the next few days! For more information and posts like this one, make sure you sign up for Zone Forecasts — where multiple detailed articles, videos, and interactives are posted each day.

Have a great Friday and an excellent Presidents Day Weekend!

 

Sunday Overview: Warming Trend For Early This Week

A beautiful Autumn weekend continues today, with high pressure still in control. But a warming trend will start today with more southwest winds, as high pressure begins to shift further south and east of the region. Highs will be in the upper 60 to lower 70s with plenty of sunshine today. These temperatures are already slightly above normal for this time of year. Clouds will be on the increase tonight as a weakening cold front approaches the region.  Some isolated or widely scattered showers are possible later tonight and tomorrow morning.  But with limited lift and moisture, these will likely be on light side.

The cold front likely washout day during the day tomorrow, as ridge from the southwest, begins building over the region. Clouds should break for more sunshine by the afternoon and unseasonable warm airmass will be in the region with temperatures well above normal. West-southwesterly winds will cause temperatures to rise into middle to upper 70s to near 80 over many parts of the region tomorrow afternoon. Some other highlights, for this upcoming week:

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