The origin of the Storm “Juno” 27 Jan 2015 (by Diego Fdez-Sevilla)
Juno has been the name of the first “big” storm that has made the news this Winter in January 2015. So how and where did it come from and, how did it look?
How and where did it come from?
I believe that two climatic events are related. A low pressure situated in previous days at the North of the Pacific ocean and the influence of warm and wet air from the Mexican Gulf getting in the path of the young Juno.
Looking at the images representing the Mean Sea Level Pressure it can be observed a very deep and persistent low pressure situated over the North of the Pacific the 23th of Jan from which the Jet Stream released a trail of low pressures moving East across North America.
Next are the images showing the atmospheric conditions between the 21st to the 27th of January for Mean Pressure at sea level, Temperature at 850 hPa and Total Precipitable Water at 850 hPa.
It seems that the Jet Stream has spread the influence of the low pressure over the Pacific and create a long corridor of low pressure at the North side of the Jet. Once one low pressure reached the warm current moving North from the Equator “Juno” built strength and acquired moisture to freeze and become snow.
Open for consideration.
I realise that there are meteorologists which will look more in detail to this event and they might see things that I might not. Therefore, I want also to mention my thoughts about the circumstances occurring in the days previous to Juno using the Daily Weather Maps Prepared by the National Centers for Environmental Prediction, Weather Prediction Center from NOAA.
The weather at the East coast of EEUU suffered the influence of a Low pressure moving from the Golf of Mexico between the days 21st to 24th. Meanwhile, considering also the images at the beginning of this post, the influence of the Pacific Low extended progressively into the North West side of North America following the north side of the Jet Stream. This situation created the bases to evolve into a corridor of low pressures or “front” which is reflected by the Weather Map the 25th of Jan. The low pressures following this front were originally the result of masses of air being dragged out from the cold and dry air being pumped from the Artic into the North Pacific Low. One low pressure arrived close enough to feel the influence of warm and wet air currents from the Gulf of Mexico, gaining strength on its winds due to thermal contrast and moisture which precipitated in the form of snow. And it was called Juno.
I might be overlooking something here but I think that all maps support my assessment. However feel free to make “constructive” comments or directly contact me by email d.fdezsevilla(at)gmail.com
How did it look Juno?
The trail connecting the Low pressure in the Pacific and Juno can be observed in the image representing a 3D reconstruction of the Pressure conditions at sea level. The “corridor” created of low pressures goes from 170W 50N to 60W 40N.
Juno seen by others.
At the website “oceanweatherservices” already pointed out the arrival of a Low pressure from the West, crossing over the Great lakes, gaining strength and threatening with high volumes of snow fall.
(21st Jan 2015) East Coast Bomb Low likely 24-25 January
An East Coast bomb low still looks likely 23rd to 25th. Expect a gale low near Cape Hatteras 12Z/24th exploding as it move northeast dropping 40 MB pressure from the 24th to 25th creating storm to hurricane force winds and waves to 13 meters (43 ft.) by early the 25th. Significant rain and snow amounts also possible along portions of the East Coast.
East Coast Storm update 23 January 2015
A fast moving and rapidly deepening storm low is still forecast to move northeastward along the US East Coast from the 24th to the 25th with winds forecast up to 65 knots and seas building to 10.5 meters (about 35 feet). Forecasts suggest that the low will deepen from 1008 MB to 950 MB over 48 hours (58 MB drop)!
Will this one be just the first “big” storm of this Winter? What next?
Here is the image showing the weather alerts being activated for Europe the 28th Jan 2015.
26 01 2015
Cold weather is again on the way for the UK. Later this week colder conditions will spread south, bringing a mixture of sunny spells and snow showers from Wednesday onwards. Temperatures for many will be below normal for the time of year and the wind chill, due to strong winds, will make it feel very cold.
Snow showers are expected to affect parts of the northern half of the UK on Wednesday and Thursday and the Met Office has issued a yellow severe weather warning for the potential impacts and this will be updated as required this week. Don’t be surprised to see some snow showers across southern areas too, but these are not currently expected to be heavy enough for the snow to settle. The northerly winds and cold weather are likely to continue into the weekend.
Is it due to the polar vortex?
There have been reports the cold weather is due to a “displaced polar vortex”. The large-scale low pressure area in the stratosphere, known as the Polar Vortex, is displaced towards Russia and looks likely to stay that way over the next few days. However this is not directly responsible for changes in the weather during the coming days. The cold northerly winds we are expecting at the end of the week are not unusual for winter.
What is the jet stream doing?
The jet stream is forecast to move south of the UK from Wednesday onwards. This means we will be on the ‘cold side’ of the jet and cold air from the poles/Arctic will work its way southwards to affect the UK.
Is the snowstorm in the USA coming our way?
The snowstorm affecting the east coast of the USA is not coming towards the UK. It is expected to move away from the States, crossing the Atlantic to the south of the UK to bring heavy rain to Spain and Portugal at the end of the week.
Following the Met Office weather forecast, “the snowstorm affecting the east coast of the USA is not coming towards the UK. It is expected to move away from the States, crossing the Atlantic to the south of the UK to bring heavy rain to Spain and Portugal at the end of the week.” I remember when the North of Spain and the UK use to share the effects of the same Low pressures in Winter. Now it seems that we are getting separated by the Jet Stream … …