Light rain today will fall today. This will be followed by a brief spell of sunny skies and calm weather Wednesday. Another storm system impacts the area Thursday, bringing some mixed precipitation and rain. On the back side of this system, a drastic drop in temperatures will take place going into the weekend. This will be the coldest air mass we’ve seen in many weeks with lows in the teens.
Rest of today – Light rain in the morning and cloudy. High temperatures in the upper-40s. Overnight lows in the mid-30s with gradual clearing.
Weather Prediction Center surface forecast for 7AM Wednesday
Wednesday – high pressure briefly builds in with high temperatures in the mid-40s. Mixed precipitation could begin later in the day as the next storm system approaches. Overnight lows in the upper-30s with increasing mixed precipitation then transitions to rain.
Thursday – A warm up takes place with a warm front and southerly flow overnight. High temperatures reach into the mid-50s with rain ending in the morning/early afternoon. Much cooler temperatures overnight with lows around 30°F once the cold front of this storm system moves through.
GFS model 1000-500 mb precipitation and thickness valid 5PM Friday. Note the large area of Canadian high pressure centered over Indiana.
Friday– strong Canadian high pressure builds behind the cold front mentioned above. A much colder air mass will accompany this high, with temperatures Friday only in the low-30s. The real chill takes place overnight, with lows dropping into the mid-teens as Arctic air keeps pumping in!
The groundhogs were unanimous in their proclamation of an early spring, but do their predictions jive with climate forecasts? Either way, the first week of February will be an active one with multiple storms impacting the area. Temperatures are forecast to start much above normal in the mid-50s, then taper down to being a touch above normal in the low-40s. Most of the precipitation that falls should be in the form of rain, though overnight periods could produce mixed precipitation.
Rest of today – Early clouds should give way to more sunny skies later in the day. High temperatures will be mild, in the mid-50s as a stationary front slowly lifts north as a warm front into the overnight hours. Overnight lows in the low-40s.
Tuesday – High temperatures in the low-50s. The warm front mentioned above stalls out, then returns as a cold front. This pattern brings the potential for some light rain showers. Overnight lows in the low-40s.
Wednesday – high pressure builds in briefly, and should give us some reprieve from rain, however, north winds will cool things off with highs in the low-40s. Overnight lows drop into the low-30s as a second, stronger storm system takes aim at the area. This one could start off as wintry mix and sleet overnight for NYC.
Thursday– any accumulation of wintry mix should get washed away as this second storm system lingers and produces rain during the course of the day Thursday. Mostly cloudy otherwise as highs climb into the low-40s. Temperatures currently forecast to remain steady for the most part overnight with onshore flow.
Are the Groundhogs Right? Climate Prediction Center’s temperature outlooks for the second half of February and the entire month suggest that the groundhogs might be on to something – at least for the eastern part of the US (especially the southeast), where above normal temperatures are being forecast. That isn’t as much the case for the western US, as you can see below.
Climate Prediction Center temperature outlook for Feb 8-12
Climate Prediction Center temperature outlook for Feb 10-16
Climate Prediction Center temperature outlook for the whole month of February
This weekend coming up will see a dramatic contrast from last weekend’s record-breaking warmth. Temperatures during the next few days will be average to below normal. Overnight lows in the low-20s for this period. A “warm up” will happen as we enter the warm sector of a passing storm Saturday going into Sunday, but reinforcing cold air arrives to start next week.
Rest of today – partly sunny with strong northwesterly winds. Temperatures will drop from around 50ºF into the low in the mid-20s overnight. A trough extending west from a departing area of low pressure that’s bringing the strong winds may touch off some rain.
Friday – a cold, sunny day with high temperatures starting off in the low-20s and only expected to reach 30ºF under the continuing influence of northwesterly winds .
Saturday – a large storm system will move through. Temperatures starting off in the low-20s will warm into the upper-30s with southerly flow ahead of the main cold front associated with this low. Thermal profiles will support snow to start, with a light accumulation possible before temperatures warm enough at the coast to transition to all rain overnight. Overnight lows aren’t expected to move much, dropping into the mid-30s.
GFS model 500 mb height anomalies for 7AM Monday
GFS model 300 mb heights and winds for 7AM Monday – the orientation of the jets stream mirrors the position of 500 mb height anomalies
Sunday– improving conditions with high temperatures in the upper-30s and partly cloudy skies. Overnight lows in the low-20s as a second and stronger blast of Arctic air flows in behind Saturday’s storm.
A quick hitting storm system brings possible light snow to the region overnight into Wednesday. High pressure builds behind this storm, with winds shifting to the northwest bringing a cool down midweek. Another storm approaches towards the end of the week. Ahead of this, temperatures surge back above normal, approaching 60°F, as southwesterly winds instigate warm air advection.
Rest of today – increasing clouds with high temperatures in the mid-40s. A coastal low passes east of the area, bringing some potential for light snow accumulations (1″ or so). Precipitation will start off as rain, though, then transition to snow briefly overnight. Overnight lows drop to around 30°F.
Weather Prediction Center surface forecast for 7PM Tuesday
Wednesday – snowfall may be enhanced by a second fast-moving arctic front. Behind this front, high pressure builds. Decreasing clouds, with winds picking up from the west then veering northwest towards overnight hours. High temperatures in the low-40s. Overnight lows will plummet quickly into the upper-20s with an Arctic air mass and northwesterly flow. Winds may gust above 30 mph during the overnight hours.
Thursday – expecting a calm, bright, sunny day with high temperatures in the low-30s, below normal for this time of year. High pressure will be moving right over us during this time. Overnight lows in the low-30s.
GFS model 500 mb height anomalies for 1AM Friday. Note the strong positive height anomaly over the Northeast, with a corresponding strong negative height anomaly over the Rockies.
Friday – high pressure will move offshore to the east, setting up warm southwesterly return flow between the western periphery of the high and an incoming storm system. High temperatures expected in the upper-40s. Temperatures should in fact warm up overnight, through the upper-40s.
A soggy and messy start to the week will give way to a blast of Arctic air, leading to an extended period of below normal high temperatures only in the 30s for the most part. Temperatures do look to rebound over the weekend towards more seasonable levels. The next chance for precipitation happens Wednesday as an arctic front, harbinger of these much colder temperatures, crosses the area and brings possible snow squalls.
Rest of today – periods of rain during the day with high temperatures in the mid-30s. Rain tapers off and ends early this evening as the low pressure responsible for the stormy conditions moves off to the east. Overnight lows drop to around 30°F.
GFS model 500 mb height anomalies for Wednesday at 7PM, note the strong negative height anomaly over the Northeastern US and St. Lawrence Valley
Wednesday – should be a mostly sunny day, though as an arctic front hits us late in the day and in the early evening, a few snow squalls/snow bands could hit. These would be brief in nature but could impinge on visibility, making travel difficult. High temperatures should be similar to today in the mid-30s. Overnight lows will plummet quickly into the upper-teens with an Arctic air mass and northwesterly flow.
Thursday – northwesterly flow continues as strong Arctic high pressure builds. This will keep temperatures only in the upper-20s for highs under mostly sunny skies. Overnight lows in the low-20s.
Weather Prediction Center surface forecast for 7AM Friday
Friday – temperatures moderate a little bit, with highs in the low-30s as the high starts moving east. Overnight lows in the low-20s.
Mild temperatures in the mid-50s are on the way along with long duration drenching rains to start the weekend. Rain tapers off Saturday evening and conditions improve Sunday with a return to more seasonable temperatures in the 40s. A chance of wintry mix or snow is possible late Monday.
Rest of today – mostly cloudy with chances for rain increasing by the afternoon. Steady rain expected overnight. High temperatures around 50°F. Temperatures actually rise overnight with southeasterly onshore flow aiding warm advection.
NAM 2-meter temperature and 10-meter winds at 11PM Friday
NAM precipitable water for 7AM Saturday
Saturday – rain continues through the day Saturday with high temperatures peaking in the mid-50s as a warm front passes and persistent onshore flow from the southeast, backing briefly to the northeast then veering south continuously advects warmer air off the ocean to the area. Overnight lows are a different picture dropping into low-40s as winds turn to the west behind a cold front.
Sunday – as the parent low bringing this rain moves north of the area and continues gathering strength, winds will pick up from the west. This will bring cooler air to the area resulting in highs in the mid-40s under partly sunny skies. Overnight lows continue a cooling trend to about the freezing mark.
Weather Prediction Center surface forecast for 7AM Sunday
Monday– another storm system will impact the area starting late in the day. Temperatures will be cold, topping out in the mid-30s. Precipitation starting late on Monday should begin as snow or a wintry mix given the currently forecast temperature profile. As is the case going into Saturday, a change in wind direction accompanying a warm front should help temperatures actually rise overnight into the upper-30s, allowing precipitation to transition to rain.
The week after we set our clocks back for the fall will see a shift to the coldest temperatures we’ve yet seen this season. High temperatures will trend from normal levels to slightly below normal (upper-50s to low-50s) before plummeting into the 40s following the passage of a low pressure center and cold front. The chilly air following this system will begin a longer term trend of below average temperatures going into the middle of the month at least.
Rest of today – mostly cloudy with a chance of showers as a cold front passes through later in the day. High temperatures on the mild side in the low-60s as we’ll be in the warm sector of the parent low bringing the cold front through. Overnight lows in the low-40s.
Weather Prediction center surface forecast for 7AM Wednesday
Wednesday – sunny with cooler high temperatures in the low-50s. High pressure depicted above will keep things nice and dry. Overnight lows in the low-40s.
Thursday – starting off mostly sunny with high temperatures in the mid-50s. A storm system will approach later in the day and bring the chance for rain at first, with rain and snow mixing possible overnight as lows drop into the mid-30s.
Climate Prediction Center temperature anomaly forecast for November 10-14
An anomalously low area of 500 mb heights will produce cold temperatures at the surface
Friday – the real cold sets in with high temperatures only in the low-40s. Rain/snow should taper off early giving way to sunny conditions, with winds picking up due to the low bringing this weather strengthening as it continues moving off to the northeast. Overnight lows are shaping up to be below freezing, near 30°F with winds forecast to die down and skies clearing allowing for some good radiational cooling.
A winter storm warning is in effect for NYC and the surrounding metropolitan region. This isn’t exactly how we’d all want to start March off! This storm is anticipated to bring some travel impacts to the area, however, for reasons discussed below, this won’t be a blockbuster snowmaker. Watch out for a slog of a morning commute tomorrow. This snow may also stick for a while – a frigid continental polar air mass from Canada will sweep in behind this storm bringing temperatures generally 10-15°F below normal for this time of year. High temperatures in the mid-30s should limit melting.
Headlines
Snowfall totals: I’m forecasting 4-6″ in parts of eastern Queens, southeastern Brooklyn, and lower totals further east into Long Island. Higher totals of 6-8″ are more likely to occur in Manhattan, the Bronx, and points further inland, particularly interior regions of Connecticut. Below are probabilistic forecast maps of various amounts of snow (>= 2″, >= 6″, and >= 8″).
Timing: Precipitation starting in earnest around 8PM. Starting out as a mix of rain/snow near the coast, but transitioning over to all snow later in the evening. The heaviest snow will happen overnight. Because of the fast-moving nature of this storm, precipitation is expected to end rather quickly between 4-6AM Monday morning in the city.
Uncertainties: There is still potential for a wobble in the storm track, further east and south would result in higher snow totals near the coast. Further west and closer to the coast would mean more mixing/rain at the coast and lower snow totals. There will be a rather sharp gradient of increasing snowfall totals spreading across the region (as seen in the previous probabilistic snowfall total forecasts). Mesoscale heavy snow bands will be difficult to pinpoint ahead of time. Some areas could see several inches more than neighboring areas just a few miles south and east.
Synoptic Set Up (The Big Picture)
A storm that’s currently unleashing severe storms with tornadoes across the Deep South now will slide up along the Mid-Atlantic and Northeastern coast of the US. As this storm progresses, it will move close to the 40°N/70°W benchmark, a spot that’s climatologically correlated to heavy snow events along the heavily populated I-95 corridor during the winter. This storm will continue to strengthen as it moves offshore. Snow is expected to develop ahead of the advancing warm front associated with this storm as its precipitation shield advances. Heavier snow is forecast to develop later on as strong isentropic lift associated with the warm front occurs, creating the potential for frontogenesis and some mesoscale bands of very heavy snow. The storm is expected to move quickly along the Northeast coast, such that the duration of precipitation in any one spot is expected to be less than 12 hours.
At the 500 mb level, a shortwave trough will provide positive vorticity and some additional lift/divergence, allowing the storm to continue strengthening. Finally, at the 300 mb level, the surface low will be close to the entrance region of a curved 300 mb jet streak. This will provide yet more divergence and lift, if only for a brief period.
Weather Prediction Center’s surface forecast for 1AM Monday morning
GFS model 500 mb vorticity and height for 1AM Monday
GFS 300 mb height, wind forecast for 1AM Monday, note the brighter red, orange, and white streak over the Northeast, indicating a jet streak.
Evolution of the Storm Track
Over the course of the last three days, forecast models have come into better agreement with this storm tracking close to the 40°N/70°W benchmark (circled in red in the images below). Note the increasingly tight clustering of storm center locations around the benchmark in progressive storm track forecasts from the Weather Prediction Center.
WPC storm track forecast issued 7AM Saturday, the brown spots indicate forecast storm center locations around the benchmark
WPC storm track forecast issued 7AM Sunday, the green spots indicate forecast storm center locations around the benchmark
The tightening clustering of these forecast storm center locations lends greater confidence to the idea that the storm will track very close to the benchmark.
Ensemble Snowfall Totals
The two primary model ensembles (GEFS and SREF) have been edging ever so slightly upwards in their forecast mean snowfall totals, while the model spread has decreased over the weekend
Latest GEFS ensemble plumes for snowfall totals at KLGA
Latest SREF ensemble plumes for snowfall totals at KLGA
These means/spreads were part of what informed my own forecast snowfall totals at the top of this post.
Factors Supporting Heavy Snow
Storm track over or very near the benchmark
Strong isentropic lift and possible frontogenesis (see images below). Strong lift is a critical ingredient for generating heavy precipitation
Possibility of mesoscale bands as a result of this lift, generating heavy snowfall rates
Temperatures probably supporting frozen precipitation through the atmosphere
GFS forecast for 850 mb frontogenesis
NAM 12km forecast for 850 mb frontogenesis and temperature advection (red shades indicate warm advection)
NAM forecast sounding for 1AM Monday
GFS sounding for 1AM Monday
Factors Suggesting Lower Snow Totals
Possibility still remains for storm track to shift further inland, introducing more warm air off the ocean, more rain than snow at the coast
Warm advection associated with the storm’s warm front possibly also affecting snow development. Note how close the overlapping temperature and dew point profiles in the forecast soundings above are to the freezing mark, the dashed blue line the middle of the image that is angled to the right at 45°. Evaporational cooling should help somewhat in staving off warming but if temperatures warm more than forecast, we could see more mixing
Mesoscale bands of heavy snow may not push far enough onshore
Surface temperatures ahead of the storm in the upper-30s near the coast, urban heat island effect could retard snow accumulation
Fast moving nature of the storm, total precipitation window only 12 hours
Small window for the best moisture support at the 850 mb level. No real evidence to suggest a low-level jet carrying a ton of moisture into the region.
NAM model forecast of 850 mb relative humidity and winds. There’s not too big of an area of completely saturated air at this level, and winds are not strong at this level either.
Although the calendar has flipped to March and we’re less than 3 weeks from the official start of spring, the weather has taken a decidedly winter-like turn as of late. This pattern will continue over the weekend and into next week. Initially, we’ll contend with 2 coastal storms that will bring chances for snow, and then enter next week with temperatures well below normal for this time of year. Sadly, this colder than normal pattern looks locked in for the next week or more
Rest of today – overcast conditions with temperatures hovering in the mid-30s. Precipitation will move back into the area by later this evening. Thermal profiles overnight point to a mix of snow/sleet at the coast with lows just around freezing. The local forecast office calls for an accumulation of 1-2″ of this wintry mess.
Weather Prediction Center surface forecast for 7AM Saturday
Saturday – the wintry precipitation continues the first half of the day as the first of two coastal storms continues to impact the region. High temperatures should warm up to around 40ºF with mostly cloudy skies, and precipitation should die off later in the day. Overnight lows should be around freezing.
Sunday – starts off as a decent enough day, but a second storm will be brewing and moving offshore, impacting the area overnight into Monday. High temperatures should be similar to Saturday in the low-40s with partly sunny skies. At this point, the primary precipitation modes at the coast appears to be a rain/snow mix. Thermal profiles don’t appear cold enough to support all snow with overnight lows expected to be above freezing around 35ºF.
Global Forecast System 1000 mb – 500 mb height, pressure, thickness foreast for 6AM Monday
Monday – precipitation tapering off early in the morning as this storm is a fast-mover. Temperatures topping out in the upper-30s with mostly cloudy skies.
Colder than Normal Temperatures Ahead
Climate Prediction Center has a 6-10 day temperature outlook suggesting a colder than normal pattern for much of the country, including our area. During this time, the polar jet stream is expected to dip further south allowing colder air to penetrate into the Continental US.
A weak cold front passes through to start the weekend. a decent weekend is in store with a chance for snow showers on Sunday night. Temperatures will be about average for this time of year through Presidents Day. We have a chance for more significant winter storm mid-week next week although details are fuzzy. At this time, thermal profiles at the coast suggest a mixed event like this past week with snow transitioning to sleet, freezing rain and plain rain. This event looks longer in duration due to a slow moving high east of the incoming storm. I will be on vacation next week and won’t be posting until the following week.
Rest of today – overcast with temperatures in the low-50s. Slight chance for rain with a weak cold front passing later in the afternoon. Overnight lows in the mid-30s.
Weather Prediction surface forecast for 7PM Friday
Saturday – mostly sunny with highs in the low-40s. Overnight lows around 30°F.
Sunday – mostly sunny during the day with highs around 40°F. Overnight lows in the low-30s will support some light snow associated with a broad area of low pressure. Not anticipating much accumulation beyond a coating.
Monday (President’s Day) – imoroving conditions. Partly sunny with highs in the low-40s and overnight lows dropping into the low-20s.
