Archives For blizzard

A “potentially historic and crippling snow storm” is imminent for the USA NE seaboard especially New York State with cities from New York to Boston being warned by weather agencies of a potentially life threatening blizzard lasting some 48 hours.  Update Tues 27: whilst the worst of the blizzard missed New York heavy snow occurred further North.  The system tracked further east than modelled.

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New York escaped worst, but Boston hit as expected with record snow in New England

 

Watch unfolding live pictures on webcams here:

http://player.theplatform.com/p/2E2eJC/NBCNewsIE8?guid=nbcnewslive_nyc1

http://www.earthcam.com/usa/newyork/timessquare/?cam=tsstreet

Potentially 36 inches (3 feet) of snow could fall in places (that’s waist deep!) as a Nor’Easter (NorthEasterly) wind buckles round a rapidly deepening low tracking NW up the coast over the next 48 hours. All weather agencies are busy getting the news out to people in the regions likely to be impacted.

Official warnings from NOAA and all regional weather agencies are giving these urban populations warning after the system has caught computer models napping.  The storm has rather unexpectedly “blown up” recently to become a potential threat only in the last 24 hours or so.

The charts below show the synoptic set-up that develops this system, named Juno, currently a rather benign low tracking west out of continental US.   This LOW is forecast to deepen rapidly due to it’s location in relation to a fast meridional jetstream looping round a HIGH pressure ridge in the US west.  The LOW is dragging cold air from the continent interior and, as this cold air interacts with humid air and plenty of moisture over the Atlantic, it will turn into a snow-making machine that could last 48 hours and dump feet of snow widely across many places indicated on maps above.

Here are some synoptic charts showing the development.  Note the track sliding up the NE coast.  The Nor’Easter wind itself can be seen developing on the northern edge of the low which, as it is forecast to slow and stall while it deepens (a common feature of bomb depressions) the strong NorthEasterly gales, some up to 70mph, will continue to pump snow across parts of the NE building up depths to 2 – 3 feet in places.

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Note the warm sea surface temperatures off shore which will provide enormous quantities of moisture for snow production on the NE wind.

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Here is a chart showing minimum temperatures and possible snow cover by Wednesday.

The US is more used to heavy snow and more able to cope with it than the UK because the USA has a continental climate which experiences colder winters with more regular and significant snow events.  Earlier this winter Buffalo recorded feet of lake-effect snow.  Even so, this snow storm is serious and a state of emergency has been issued for New York.  The difference this time is that this storm will dump a lot of snow in a very short space of time and more people will be impacted in a densely populated and urbanised part of the USA.

The National Weather Service and regional weather agencies and the New York Mayor have all issued weather warnings for the blizzard urging people not to underestimate the possible impacts of 2-3 feet of snowfall over the next 48 hours.

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http://www.nbcnewyork.com/news/local/NYC-New-York-New-Jersey-Connecticut-Blizzard-2015-NorEaster-Snow-Wind-Whiteout-Record-289770081.html#

Here are some tweets and information emerging on the eve of this storm:

 

More info:

Excellent write up and explanation of the evolution of this Nor’Easter storm http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/01/28/raging-snow-howling-wind-the-meteorological-evolution-of-the-blizzard-of-2015/

http://forecast.weather.gov/product.php?site=NWS&issuedby=OKX&product=WSW&format=CI&version=1&glossary=1&highlight=off

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2902

http://edition.cnn.com/2015/01/25/us/weather-storm/

http://www.bbc.co.uk/weather/features/30989760?ns_mchannel=social&ns_campaign=bbc_weather&ns_source=twitter&ns_linkname=news_central

http://www.climatecentral.org/news/what-warming-world-means-for-major-snowstorms-18594

http://meteorologicalmusings.blogspot.co.uk/2015/01/a-meteorologists-thoughts-on-blizzard.html

http://www.bbc.co.uk/news/world-us-canada-30996010

Here is a summary of the causes of the March 11 2013 “Channel Blizzard” which brought extra-ordinary “Spring” weather to SE England and the Channel Islands and N France. At RGS we had record low wind chill temperatures of -10°C at 9.30am, 36mph gusts and sub-zero temperatures all day.  Follow the numbers on the map to get a quick view of why it all happened!

1. Cold source region for Polar Air: the NE winds originated from the Polar regions with temperatures below -15°C and traveled across an extremely cold continent to reach the UK.

2. On their journey, the North Easterlies warmed a little over the North Sea (by now +4-5°C) which caused showers to form in unstable air (warming causes air to rise, clouds form and it snows). These showers formed lines called “snow streamers” which fed snow to the SE for most of the day and into Tuesday morning.

3. Much warmer SW winds at +10°C met the frigid cold Polar air mass somewhere over the Bay of Biscay but they didn’t mix well and they certainly didn’t get on!  In fact, the cold, dense polar air pushed the lighter, less dense tropical air right up off the ground, to over 4000m, where all the moisture condensed, formed cloud and snowed!  The high winds experienced across SE England were “squeezed” like toothpaste between the HIGH over Iceland the LOW over France (a high “pressure gradient”: look how close together the isobars are over SE England and the Channel!).

4. Next? Things will stay cold during mid-week as the UK remains firmly in Polar air and enjoys some dry weather courtesy of a HIGH over Iceland (unusual).  Clearer skies and frosts.  However, a Polar Low forming SE of Greenland at the moment is due to break through the Icelandic HIGH later in the week and bring unsettled conditions to the end of the week / weekend: as Polar air is still involved this may bring further snow and sleet.

Greenwich Lightship is a UK Met Office weather station in the middle of the English Channel. 3 metre waves, 50mph winds, sow and 10 foot waves were recorded.  Unbelievably horrendous conditions which the Channel Islands experienced as a blizzard.

Watch the satellite animation below and spot the storm winding up in the Bay of Biscay before it hits the Channel and says “Hello” to France and the UK!

A severe blizzard in the English Channel will brush perilously close to Reigate today and overnight. Sub-zero temperatures for the next 48 hours and strong gusty easterly winds of >20mph will make it feel like -10ºC and potentially much lower (see wind chill charts posted earlier).  Whilst the UKMet-Office model refuses to bring any significant snow to Reigate other weather models certainly do!  In fact, some forecast as much as 10cm of snow to our region falling later Monday and overnight especially. With cold temperatures and strong winds this snow will blow around and be very unpleasant indeed, and could amount to 10cm, especially south and east, less west and north.  Updates @RGSweather on twitter.