Monthly Archives: February 2014
NYC Weekend Weather Update & CA Storms – Feb 27, 2014
First up for the NYC area is a bitterly cold end to the work week.
A reinforcing arctic cold front is set to push through the area during the day today, perhaps spurring a few scattered moderate-heavy snow showers. Accumulation, if any, should be light. Behind this frontal boundary, a west wind between 15-20mph will usher in some of the coldest low temps we’ve seen in recent weeks. Lows in the city are forecast to be in the low teens, with zero to single digits in the interior. Wind chill values tomorrow morning will hover around zero.
Friday will be a sunny day with high pressure moving in. Despite the sunshine, temps will struggle into the 20s across the region.
Saturday, a weak frontal system moves through, but with dry atmospheric conditions, little if any snow is expected. Highs will be in the low-mid 30s.
Sunday-Monday, a prolonged winter weather event is forecast. The storm system currently impacting the west coast (see below) will move over the interior of the country, reorganize, and strengthen over the Midwest. This will lead to a stalled cold front draping across our region with multiple low pressure centers to slide along this front. One of these is forecast to develop into a potentially significant coastal storm. Models are coming into agreement that this storm center could pass close to the 40N 70W benchmark sweet spot.
The duration of the storm, starting Sunday night through Monday night means that it could result in significant snowfall, even with possible mixing in with sleet/rain near the coast during the day Monday. Still too early to tell how much snow – will keep monitoring the situation. High temps on Sunday will be in the mid 30s, then drop back into the low 30s for Monday.
Too much of a good thing for California?
As I noted in earlier posts, and as has been broadcast by the media, California remains in the grips of a crippling drought. A strong pacific storm system is spinning up multiple bands of heavy precipitation during the end of this week. While that is some good news for the drought, the intensity of the rainfall could lead to mudslides, and localized flooding. The best news out of this storm is that elevations over 7000′ are expected to pick up as much as 1-3′ of snow, adding to a paltry snowpack thus far. Check out the graphic from the San Diego NWS station for a look at the heavy rain fall totals expected (5-7″ in higher elevations near the coast with south facing slopes!).
NYC Weather, Relief for CA, A Stormy Monday for NY? – Feb 25, 2014
Keeping eyes peeled on the forecast for Monday, when the next strong storm system is forecast to arrive.
First, there’s some good news for our friends out west. As you can see in this first image, the GFS model is showing a storm system originating in the Pacific bringing areas of moderate to heavy rain over the weekend for California, which is currently in the grips of an historic drought. As the storm center approaches the coast, a strong cold front will swing from south to north through the state. This frontal boundary will spark thunderstorm and rain which should bring mild relief, with 1-2″ of rain forecast for coastal and valley areas, and 2-4″ up to 6″ for south-facing mountain slopes. In addition, heavy snow could fall in the higher elevations of the coastal ranges and Sierra. Welcome news for an area of the country that’s in need of moisture.
After the storm exits the western US, it is forecast to reorganize over the plains and Midwest, then track into our area. Right now, it’s still to early to say with certainty whether the intensity of the precipitation this storm brings, and whether it will be all snow, a mix, or even mostly rain. Will keep you all updated.
NYC Weather: It’s gonna get cold – Feb 25, 2014
The big weather story for the NYC region this week is going to be the return of bitterly cold temperatures across the region, thanks in part to our least favorite visitor, the polar vortex. By the end of the week, we’re looking at high temperatures in the mid to low 20s in the city, with lows in the teens to single digits. To put that into perspective, highs in the low 20s are 20 degrees below normal for this time of year, and just over two standard deviations from the mean.
There is one shot at precipitation during the work week, which is coming Wednesday. Fortunately for us, this storm will be taking a more southerly track, meaning that we’ll likely see under 1″ in the city, with slightly higher amounts out in eastern Long Island. Areas north and west should see trace to no accumulation from this system.
Today – increasing clouds with a high near freezing.
Wednesday – high near freezing, snow flurries likely, especially from the city east. Light accumulation under 1″ in the city – slightly higher east.
Thursday – the polar vortex returns along with a reinforcing dry arctic cold front. Mostly sunny with temps near freezing, but dropping rapidly during the evening hours with an overnight low in the teens.
Friday – clear skies but a high temp only in the mid 20s, overnight low in the teens.
Next shot of precipitation comes Saturday, associated with another arctic cold front. An area of strong high pressure will build in behind the front, pumping in frigid air from Canada for the end of the week.
Interesting to note that the ensemble forecast for the Arctic Oscillation is unanimous at this point that we’ll see a negative phase. As I noted in the earlier post linked above, these negative phases of the AO are often associated with the abnormally cold temperatures, and that certainly looks to be the case again this time around.
Really Cool Graphic – Tornado Tracks from 1950-2013 Mapped
Just a super interesting graphic that the Storm Prediction Center put together using GIS data. What you’re seeing is a graphical representation of the track of each tornado that’s impacted the continental United States from 1950-2013. Notice the density in Tornado Alley, a region of the country where geography is conducive to the large scale weather patterns that produce tornadoes. Also, check out the general trend of a northeast vector to the tornado tracks. Lastly, note that although tornadoes are considerably less common in the Northeast, they still do occur with some frequency.
NYC Weather, The Week Ahead: Return of the Polar Vortex
A most unwelcome weather pattern in store for the NYC area this coming week: the polar vortex will make its return! Refer to my earlier post about the Arctic oscillation providing conducive conditions for the influx of frigid air into the Northeast for an in-depth analysis on this.
Sunday – another day of fairly mild temps near 50 ahead of the first of several cold fronts. This frontal system has the potential to bring some rain showers along the coastal areas and NYC proper, with some accumulating snow in higher elevations north and west during the overnight hours Sunday. Overall conditions are not that favorable for a high impact event, so I wouldn’t expect anything too out of hand.
Monday – with the passage of the cold front, a cooler day is in store with highs in the mid 40s and winds picking up from the northwest, 15-25mph and gusts up to 35mph. Monday night, the chill sets in.
Tuesday – highs will only top out around freezing in the city as the polar vortex takes hold. A dry day with increasing clouds as we watch the next storm system move in Tuesday night.
Wednesday – all eyes turn to the North Carolina coast as forecast models suggest the development of an area of surface low pressure that then tracks northeast into offshore waters of Long Island. As is generally the case this far out, uncertainty about the storm track, snow-to-liquid ratio, and available moisture make it difficult to be certain as to the impact of this storm. At the minimum, would expect something like 1-3″ in the city with snowfall totals increasing eastward. High temps again struggling to make it above freezing.
The remainder of the week will see the polar vortex become entrenched with high temps only in the mid-upper 20s. At least there aren’t any more storms on tap until the weekend!
NYC Weather Update, Looking Ahead & the Arctic Oscillation (AO) – Feb 20, 2014
A strong frontal system that’s currently pushing its way into the Central Plains will be arriving in our area Friday, bringing showers, potential thunderstorms, and much warmer temps. Currently, the storm system is impacting a wide swath of terrain. Blizzard warnings up for most of the state of Iowa, and heavy snow is expected across Wisconsin and Minnesota.
Though this storm will weaken somewhat before it hits our area, it should nonetheless bring widespread rain showers with the possibility for a strong thunderstorm and wind gusts up to 50mph. Temps tomorrow will range in the mid 50s with a warm front passing over tonight and southwest winds pumping in warmer air ahead of the cold front tomorrow. Timing of the cold front passage looks to be in the late morning/early afternoon. Rain showers/thundershowers could band together and form a continuous line with some embedded stronger thunderstorms. Chances of  strong thunderstorms are slim, though. As you can see below, the Storm Prediction Center in Norman, OK, placed the far reaches of southern New Jersey in its outlook for severe weather.
Once the cold front passes, temps will regress back to average over the weekend, with temps on Saturday expected to top out around 50 under mostly sunny skies, and highs on Sunday in the mid 40s. Our reprieve from the cold will be short, however, as a reinforcing cold front will pass on Sunday, opening the door to a longer term trend of colder and below average temperatures.
You might be wondering why this has been such a cold winter for the Northeast. Well, something called the Arctic Oscillation (AO) is a contributing factor. The AO is a measure of the strength of the arctic jet stream. When the AO is positive, it means the arctic jet is strengthening. When negative, the AO signals a weakening in the arctic jet. Negative readings on the AO index generally correspond with colder surface temperatures. Why? When the arctic jet is speeding up and growing stronger, it keeps the coldest air trapped around the polar regions. When the arctic jet slows down, it allows this colder air mass to move southward, shifting the jet along with it. In extreme cases, it can even allow polar vortexes to take unusual orientations.
If you take a look at the AO Index bar graph below, you can note that the AO index was indeed negative during the latest outbreaks of bitter cold temperatures in our region.
I bring this up because the forecast for the next 7 days indicates a return to a negative AO regime, which should lead to colder temperatures through the week. This won’t be as bad as other cold spells, since the angle of the sun is about what it would be for early October, and the days are getting longer, allowing for more daytime heating. Currently forecast highs in the Monday-Wednesday timeframe are all just under freezing for NYC.
There are some slight chances for precipitation Tuesday, but the next significant storm system looks like it will impact the area around Wednesday. Given the temperature trend, this storm should fall as mostly snow, so we’ll see how subsequent forecasts turn out on storm track and available precipitable water.
NYC Midweek Weather – Feb 19, 2014
Sorry about the lapse in posts! Tuesday ended up being a pretty active weather day with showers moving through the area (thank goodness temps were warm enough so that it wasn’t more snow).
Your weather forecast for this week: rain has already dissipated across the region. Thursday starts out as a mostly sunny day, and highs should top out in the low-mid 40s, slightly above average in the city. Clouds will build throughout the day as a frontal system approaches from the west. Overnight Thursday, chances of precipitation increase along with the passage of a warm front.
Friday, temps continue to increase to the mid 50s ahead of an approaching cold front. Expect a mostly cloudy day, with showers and the potential for a line of stronger thunderstorms accompanying the frontal boundary passing in the afternoon.
Things dry out this weekend, with temps falling back to the mid 40s Saturday and Sunday. Another reinforcing cold front passes through Sunday, dipping high temps in the beginning of next week into mid 30s, below the average of around 40. No major storms on the horizon past Friday!
NYC Weekend Weather Update – Feb 15, 2014
We will be feeling the impacts of yet another storm, in what seems like an endless winter. A low pressure system currently over Cape Hatteras will move offshore into the Atlantic shortly. Once it does so, it is forecast to strengthen rapidly as it moves northeast towards the 40N 70W benchmark, which is associated with prime conditions for growth of strong nor’easters and winter storms.
Currently, forecast models are showing the brunt of the storm hitting Southeastern Mass and New England. In areas, the NWS office in Taunton is confident that there could be up to 12-15″ of snow, in addition to strong winds in excess of 50mph that have led to blizzard warnings for east facing shores of Mass including the Cape.
Impact
For our area, eastern Long Island is expected to see enough of a heavy snow band forecast to rotate around this storm to have winter storm warnings issued. These areas could see 6-8″+ of snow from this storm. Projected snowfall totals drop significantly as you go west, with mid-Island and Central Connecticut forecast to see 4-8″, and points west (including NYC) receiving 2-4″. Wind will also be a factor with a tightening pressure gradient caused by the rapid intensification of the coastal low.
Timing
Light snow is already falling over the area now, but the worst of this storm should take place in the evening and overnight hours. Snow and wind should pick up in intensity from southeast to northwest throughout the day. If you have made plans to travel along the NYC-Providence-Boston corridor, expect travel conditions to become hazardous this evening/night. The most intense part of this storm will be ongoing from about 6PM-1AM, but accumulating snow will begin around 3PM.
Notes
As with most storms this winter, there is still uncertainty as to the final track of the storm. Should the storm track slightly westward, and the deformation axis determining where a heavy band of snow progresses further inland, then areas west of where current winter storm warnings exist could see significantly higher snow accumulation. There is also some indication that a norlun trough might form, leading to a intense snow band projecting west/northwest from the center the coastal low. If this feature does develop, areas that this trough sits over could see much higher than projected snowfall.
Satellite image of the incoming storm below:
NYC Weekend Weather – Feb 14, 2014
Check out this impressive satellite image of the nor’easter that hit us yesterday. It’s now offshore of southeast Maine, and has strengthened considerably, taking on a classic “comma head” structure that is a hallmark of strong surface low storm systems.
Don’t shoot the messenger, but we are forecast to get even more snow Saturday. A clipper system to our northwest over Michigan will combine with another low pressure system moving into the Carolinas later today. Once this system moves offshore, it will begin strengthening and growing into another nor’easter. Luckily, forecast models are currently showing much lower amounts of available moisture (precipitable water) for this upcoming storm. In addition, even though the storm is forecast to pass near us, the bulk of the precipitation is currently forecast to remain over the open ocean. What this means is that we should only see light accumulations of snow, on the order of 1-3″. However, as with the previous storm, there is still a little uncertainty about the final track of this storm, and changes could lead to higher snowfall amounts.
Otherwise, expect milder temps today with windy and sunny conditions prevailing, temps in the low 40s. This should help some of the snow to melt. We should have clear skies for part of the evening to see the full moon on Valentine’s Day. Clouds move in overnight, with snow showers during the day Saturday and a high in the mid 30s. Another weaker clipper system moves in Sunday with another chance for light snow and high temps around freezing. Yet another system is forecast for Monday night into Tuesday, which looks to be snow to start and snow transitioning to rain on Tuesday. Monday’s high near freezing with a warm up Tuesday ahead of the frontal system moving in.
Here’s a graphic showing the snowfall totals from around the area from this last storm.
