Doug Simonian

A Technical Discussion on Tuesday’s Snow

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We have another November snowfall event on the way for tomorrow – which is pretty unprecedented. It should not be a major snow event, but at the very least it should whiten the colder surfaces in most locations.

Forecast models have been showing a pretty weak disturbance traversing across the country from west to east, projected to pass south of Long Island. There won’t be much in the way of wind with this system because the storm itself will not be strong enough to create much of a pressure gradient with the high pressure to the north. However, despite the weak storm, precipitation should spread throughout the New York Metro region via overrunning – warm air to the south is colliding with cold air to the north, creating lift and precipitation.

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John Homenuk

Another autumn snowfall possible Tuesday

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NAM Model showing simulated radar precipitation types at 2pm on Tuesday November 27th, 2012. Notice the rain/snow line over Central NJ and along coastal areas of New Jersey, Long Island, and Connecticut.

Storm Overview

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Many areas having already received a pre-winter snowfall in Early November, a second wintry system is on the way Tuesday — one which could provide another light to moderate snowfall before the start of meteorological winter on December 1st. November snowfalls are not unheard of, but are rare — and seeing two in one month is exceedingly rare. This storm doesn’t look to pack the same significant potential as the first one, as it will be a much weaker system with less heavy banding. The heavy, slow moving bands of snow are what were largely responsible for the high snowfall amounts in the early November event, known in meteorology as deformation bands. These bands form where storms produce enhanced areas of lift and can often produce snowfall rates of 1-3″ per hour. Our system is swinging through from the west-northwest, and will eventually move off the coast and start strengthening once it’s well to our northeast.

Even despite the system being suppressed a bit, without any explosive strengthening or development, there will be a some moderate precipitation. The question becomes whether or not this precipitation can fall and stick as snow. This will be much easier inland, and in the higher elevations. Near the city and on the coast, there will be warmer air in place at the surface. This means that in order to cool the air, heavy precipitation needs to fall. Forecast models indicate that precipitation could fluctuate between rain and snow in these areas, depending on how heavy the precipitation is falling. This does not bode well for accumulating snow in these areas.

Snow and rain could begin as early as 8am Tuesday, and will continue throughout the day. The heaviest precipitation is expected to fall between 12 and 4pm, with precipitation lightening afterwards..but possibly continuing through the evening rush hour. By later Tuesday evening, the storm is expected to head to our north and east and precipitation will wrap up over Long Island and Connecticut.

Keep reading for details and forecast graphics/snow forecast maps…

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John Homenuk

Forecast: Seasonable, dry weather holds until weekend

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NAM model showing cloudiness around the area on Tuesday afternoon. Notice the low clouds (solid grey) near the coast, and mid/high clouds (light/dashed) inland.

A stretch of dry and pleasant weather has continued into the early part of this week, and the seasonable and dry trend will continue through the middle and end of it as a high pressure remains in control. The pattern looks to change in the long range, but for now it will remain seasonable as a low pressure system passes well offshore to our east. The system will provide periods of clouds from Tuesday through Thursday, however, as a northeasterly flow around the system offshore brings in some marine air, especially along the coast. Temperatures, which have been running 5 degrees or more below average for the month, will remain slightly below normal to near normal during the week. The next chance for precipitation looks to come at the end of the week into the weekend, when a cold frontal system will sweep through the Northeast. Some snow or rain squalls/showers are possible with this passage – which will bring in a very cold airmass.

Tuesday: Partly sunny with highs in the lower 50’s, a bit cooler away from the coast and city. High and mid level clouds will be around beginning in the late morning and afternoon, so we may not see much full sun — but some of these could burn off at times. Northeast winds around 10 miles per hour.

Tuesday Night: Mostly cloudy with temperatures falling into the 30’s and 40’s and northeast winds continuing.

Wednesday: Partly sunny with highs a few degrees warmer, in the low to mid 50’s. Northeast winds continuing but less clouds than Tuesday and Tuesday Night.

Looking Ahead: Models are keying in on some low clouds and fog developing Wednesday Night into Thursday, so it could be pretty gloomy to start the day. This should burn off by afternoon but may have some trouble doing so given the persistent northeast winds and marine air. Beyond this, some clearing for Friday and then a cold front passes this weekend bringing a chance of rain/snow showers and much colder air by early next week.

John Homenuk

Forecast: Cool, pleasant weather underneath high pressure

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GFS forecast model showing a high pressure system dominating the weather pattern over the Northeast US through the end of the weekend, with little chance for precipitation.

Stormy and unsettled weather haD become a fact of life in our area over the past few weeks, but the changed weather pattern will bring a much needed respite in activity through the end of the week and this weekend. A dome of high pressure building in over the Eastern US and a fast, progressive pattern in the mid levels of the atmosphere will keep the storminess away for the foreseeable future. Seasonable temperatures are also expected through the weekend, with overnight lows dropping into the 20’s and 30’s inland (warmer near the coast) and daytime highs scraping into the 50’s. No precipitation is expected through this weekend either, with plenty of sun to go around. A free and easy forecast.

Thursday: Partly cloudy, cool, but plenty of sun. High temperatures in the upper 40’s and low 50’s throughout the area. North/northeast winds around 5 to 10 miles per hour.

Thursday Night: Partly cloudy, cool. Lows in the upper 20’s inland, mid 30’s in the city and near the coast. North winds continue.

Friday: Mostly sunny once again, a bit warmer than the past few days with highs into the lower 50’s (slightly warmer in some locations). North winds continue, though, around 10 mph.

Saturday: Mostly sunny once again, with high temperatures again reaching into the low to mid 50’s. Much of the same as Friday — with no precipitation expected and just a few clouds.

Looking Ahead: Forecast models have trended weaker and farther out to sea with a potential storm system early next week. The progressive mid level pattern is expected to keep things moving — and not allow the storm to crawl up the coast. We’ll keep a close eye on it, but for now it looks like more dry conditions are expected through early next week with just a chance of some more clouds and unsettled seas with a northeast wind if the storm gets close enough to the area.