Update: 21st of May, 8:00 a.m. UTC

After hammering India and Bangladesh, Amphan is forecasted to move north-northeastward and weaken into a depression later today. The maximum sustainable winds, which may be carried by the storm, are 50 km/h (27 KT).

Thunderstorms with gusty winds are likely to occur over Bihar and isolated places such as Assam, Arunachal Pradesh and Meghalaya.

Due to the correct timing of rescue teams deployment, there is a minimum human loss.
The worst damages has been concentrated in the West Bangal districts and Sunderbans, which suffered immense destruction.

Update: 20th of May, 4:00 p.m. UTC

The super cyclone Amphan hits India and Bangladesh with its landfall between Indian town of Digha and Hatiya Islands in Bangladesh. Storm is dumping heavy rain and damaging winds on Kolkata leaving a trails of destruction. Reported damages are destroyed houses, power cuts and downed trees.

Cyclone is now moving at 31km/h (17 KT) near 22.2N 88.3E, roughly 25 NM from Kolkata with maximum sustainable winds 138 km/h (75 KT) and gusts 166 km/h (90 KT).

Amphan will move north-northeasterly passing trough the Sunderbans and gradually weaken.

Update: 20th of May, 8:00 a.m. UTC

TC Amphan was moving at 25 km/h (14 KT) near 20.5N 87.9E approximately 129 NM South-Southwest of Kolkata in the last 6 hours. Maximum sustained winds were 157 km/h (85 KT) and gusts 194 km/h (105 KT), which makes it a Category 2 Atlantic hurricane and the strongest storm ever recorded in the Bay of Bengal.

Anticipated landfall still remains for Wednesday evening hours local time (5:30 pm Wednesday IST) near or just east of Hooghly River south of Kolkata.

Impacts

Cyclone could bring very strong storm surges up to 5 meters (16.4 feet), causing roadblocks, power link outages and destruction of houses and crops.

Evacuation of people continues, but a pandemic situation puts a great stress on the whole operation as it became difficult to maintain social distancing.

Update: 19th of May, 02:00 p.m. UTC

Super cyclone Amphan has been already marked as extremely intense in the region and the second strongest storm since 1999. Cyclone is due to make the landfall into West Bengal, Digha and Hatiya Island in Bangladesh during Wednesday morning.

In the last 6 hours, cyclone was moving 16 km/h (09 knots), located at 17.0N 86.9E, 377 NM South-Southwest of Kolkata, India with maximum sustainable winds 203 km/h (110 KT), gusts 250 km/h (135 KT).

Impacts

Storm is expected to weaken before the landfall, but the results could be still devastating with heavy rainfall and tidal waves causing flooding and strong winds resulting in significant physical damage.

Update: 19th of May, 00:00 a.m. UTC

Amphan has strengthened to a Category 5 hurricane, its position is approximately 480 NM south-southwest of Kolkata, India - 15.2N 86.6E, the current movement has been at 14 km/h (08 knots) in the past 6 hours.

The maximum sustained winds are 240.76 km/h (130 KT) and gusts 296.32 km/h (160 KT). The landing will be likely between Kolkata, India, and Chittagong, Bangladesh on Wednesday afternoon or evening. Cyclone is expected to be a hurricane Category 3, when it makes the landfall.

There are already signs of eyewall replacements, which could halt the Amphan's further intensifying. However even if the winds weaken, the real dangers is going to be a potential catastrophic storm surge up to 4–6 meters (13–20 feet).

Update: 18th of May, 12:00 a.m. UTC

TC Amphan is moving near 13.6N 86.4E with maximum sustainable winds 259 km/h (140 KT) and gusts 314 km/h (170 KT).

The cyclone is expected to hit Odisha states and West Bengal on Wednesday noon local time as a super cyclonic storm. Amphan will gain strength in the next 12 hours, but could weaken as it reaches the coasts.

Odisha state is already evacuating citizens to a cyclone shelters, more than a milion people is planned to be evacuated from coastal areas.

Update: 17th of May, 4:00 p.m. UTC

Tropical cyclone Amphan is currently strengthening in the Bay of Bengal near position 12.0N 86.4E with maximum sustainable winds 138 km/h (075 KT) and gusts 166 km/h (090 KT).

At the moment the cyclone is a category 1 on a hurricane scale and could likely become a hurricane category 3, when it reaches coasts in the northeast. The landfall is predicted to occur from Tuesday night through Wednesday.

The movement for next 12 hours is forecasted to be near 13.1N 86.5E and winds 157 km/h (085 KT), gusts 194 km/h (105 KT).

Impacts

Amphan will bring a strong winds and heavy rainfall, causing dangerous flooding with a possibility of a storm surge for vulnerable areas, especially for Bangladesh.

https://www.windy.com/upload/5ec16efe6d85e3001d6ecd01?satellite,20.108,85.761,6,internal

Reading the latest news, everybody has to be concerned about the Coronavirus and its impact on daily life of billions of people. The Coronavirus (virus is officially labeled as SARS-CoV-2 and its disease as COVID-19) is spreading quickly around the world, causing unprecedented lockdowns of huge regions and cities, havoc on markets and overload of health facilities in affected areas.

Some countries seem to have already contained the major spread of virus (China, South Korea), some are currently experiencing the initial extreme increase of patients with severe cases (Italy, Iran), with the rest of the world expecting it in upcoming weeks and trying to prepare for it.

Question is, will the rate of spread slow down or even disappear at all? It definitely will.

Check this nice video demonstrating the principle of exponential growth and epidemics

It’s essential to understand that even a very small decrease in “probability of exposure becoming an infection” (referred as p in the video) can reduce the growth of the spread significantly or even stop it completely.

But why do we discuss it at Windy.com, we normally talk just weather, right?

The reason is the outside temperature. Spread of typical flu highly correlates with weather, having its season peak in cold months, declining during spring with almost no cases during the warmest part of the year. Recent studies show that high temperatures and especially high humidity slows the influenza spread. More moisture in warmer air behaves as a barrier for airborne viruses so droplets of cough or sneeze cannot travel as far as they would in colder, dry air.
Of course, more factors can play a role in this flu seasonality (longer sunlight exposure, less clustering of people indoors), but temperature is considered as the major one.

There is a whole family of coronaviruses, some of them already known to humans, causing mild colds and behaving similar to the flu - in warmer climate, they tend to decline. That is the reason why many people believe that same will happen with COVID-19. As stated above, even the slight decrease in person to person transfer rate of the virus has a huge impact on overall number of cases. Will a higher temperature and humidity help us in this way? There are many opinions on that subject, but most experts agree, that it’s too early to judge and only hard data from summer season and their detailed analysis will tell us the truth.

But until then, we have no other option than to make assumptions based on data we have now.

Posts discussing weather patterns (temperature/humidity):

Also check out:
Coronavirus outbreakt

The perspective

As mentioned, the COVID-19 is not all that unknown to us, we had coronavirus strain SARS back in 2003. SARS had its peak in winter months and faded away during May. Typically influenza season falls sometimes between the beginning of fall and the end of spring. So the SARS did not really exceed the usual influenza season trend. But can we expect COVID-19 to follow this path as well?

The current spreading rate tells us a fact, that the COVID-19 has more incidences in places with dryer and colder environment than in more humid and warm locations. For instance let´s take a look at Japan, we would expect the virus to be spreading mainly in big cities like Tokyo, due to a number of foreign visitors and population. But this is not the case, COVID-19 is actually spreading in Hokkaido, despite it has a much lower frequency of travellers. However the weather conditions there are favorable, dry and less humid environment. The same goes for Italy and its epicenter Milan. North of the country is significantly more affected than the south.

On the other hand, it would not be wise to expect the novel coronavirus to behave as the ones before.
It is necessary to say, that SARS 2003 did not go away just because weather got warmer. It was followed by national interventions to isolate cases and everyone, who had the possibility to be infected.

We have already said that the environment plays a key role in influenza activity and dry/cold weather with low humidity favors the transmission. But influenza epidemics often appears in a tropical and subtropical regions during rainy seasons with obviously high humidity values. In other words, there are two types of influenza environments. In cold-dry environment, where humidity/temperature goes below 11–12 g/kg and 18–21°C, influenza peaks during cold months. In humid-rainy case, if humidity/temperature does not go under those values, influenza peaks during rainy season.

Immunity is another factor, which is worth a consideration. Our immunity is significantly worse in winter than in summer and we also lack vitamin D, because of less ultraviolet light exposure in cold months. Vitamin D benefits our immune system and helps us to be durable against numerous diseases, even so this factor can be observed as not so important in relation to influenza activity.

But then again, new viruses are likely to persist longer than a common ones, which have been in the population for years or decades.

Available data

We at Windy.com are no experts in the area of viruses, but we have access to the best weather data available.

We have assembled temperature records for each country (taken from the area of major spread of the virus within the country or the capital of that country) and pictured them along with recent Coronavirus spread data (daily amount of new cases, sourced from Coronavirus COVID-19 Global Cases by Johns Hopkins CSSE) to see if there could be any correlation.

Based on the charts above, we can see a slight correlation in relation with a higher temperature and virus decrease, and opposite a lower temperature and faster spread of COVID-19.

Of course, there are many drawbacks in this approach:

• data coming from different countries aren’t easily comparable (some countries test much more than the others, some have much highly populated areas, also quality of data coming from some countries is more than questionable)

• the virus has quite a long incubation period, therefore “new” cases are being reported several days after the people were actually infected (but at least average temperature at given location can help to mitigate this effect)

• there are still not that many daily observations, the data window is quite too small

• correlation does not imply causation” - even if there seems to be a visual dependency between the temperature and the increase/decrease rate of new cases, it is absolutely no proof that there is a correlation between those two

As always there are many opinions and very little data to predict anything for sure. So the truth will be somewhere in the middle. It should be essential to avoid any catastrophic predictions as well as not to underestimate it.

The latest data for China shows a retreat of Coronavirus cases and high amount of recovered patients in a comparison to the total amount. Other countries will hopefully have the same progress.

---

Not happy with the findings? Don’t despair. If the weather won’t help us, there are still many ways, how each of us can help - avoid crowded places, work remotely if possible, stay fit, wash your hands, do not touch your face.
Avoid face to face social contacts for a while - read a couple of books or go online! There is still a lot to explore, also at Windy.com.

Update: 4th June 00:00 UTC

TC Nisarga is now moving northeastwards towards Nashik and continues to weaken, the current sustainable winds are 75km/h (40 KT). Movement speed was 27 km/h (14 KT) in the last 6 hours.

Dhule and Nandurbar districts may experience heavy rainfall and gusty winds.

Track the latest severe weather predictions with the most accurate data, subscribe to Windy Premium and get 1 hour forecast with detailed informations.

Update: 3rd June 3:00 p.m. UTC

Tropical cyclone Nisarga, the equivalent of a Category 1 hurricane, battered western India with torrential rainfall and strong winds. It is also the first cyclone to strike the city of Mumbai in history.

The landfall itself did not cause major damages, despite the winds speeds more than 100km/h (53 KT) as it reached the land.

Moving further inland, cyclone lost its strength quickly and was downgraded to a deep depression. However the next few hours are still crucial.

Cyclone is now moving at 25 km/h (14 KT) with position 19.6N 74.2E. east of Mumbai, maximum sustainable winds are 60 km/h, gusts 90km/h (48 KT). Expected movement in the next 12 hours is 21.0N 75.8E.

Update: 3rd June 9:00 a.m. UTC

Nisarga has made a landfall around noon local time near Maharastra’s Raigad district with stronger maximum sustainable winds than expected 140 km/h (75 KT) and gusts 166 km/h (90 KT).

However the landfall is far from gone, it will take 3 hours to complete, the current position is 18.3N 73.3E, cyclone is located approximately 65 NM south of Mumbai.

The cyclone will move gradually over the land, the next expected direction is 19.5N 74.5E towards Panvel, Maharastra. Winds speeds should weaken to 92 km/h (50 KT), gusts 120 km/h (65 KT).

Update: 3rd June 5:00 a.m. UTC

Cyclone Nisarga has been moving at 13 km/h (7 KT) in the past 6 hours and its position is 17.2N 72.1E, 130km south-southwest of Alibagh, town in Maharashtra’s Raigad district.

The storm has intensified to maximum sustainable winds 110 km/h (59 KT) and gusts 120 km/h (64 KT).

Predicted landfall is today between 12pm and 3pm IST just the south of Alibagh. Heavy rainfall is expected with a storm surge of about 1-2 metres height.

This will affect low laying areas of Ratnagiri district mainly and Mumbai, which is on the path of the cyclone.

Update: 2nd June 9:00 a.m. UTC

A deep depression has intensified into a cyclonic storm in the Arabian Sea and is predicted to become a severe cyclonic storm named Nisarga in the next several hours. Storm has been moving at 11 km/h (5 KT) northwards in the past 6 hours.

The current maximum sustainable winds are 70 km/h (37 KT) and gusts 90 km/h (48 KT) with a position LAT 16.0/LON 71.5.

The strom could possibly bring a devastating winds of 110 km/h (59 KT) and gusting to 120 km/h (64 KT).

The expected landfall is either on Tuesday night or early Wednesday morning 3rd of June over Mumbai, north Maharashtra and Gujarat coasts.

https://www.windy.com/upload/5ed7547c18b9f0001d7b3c59?satellite,15.739,72.993,7,internal

And it truly was.. Windy team once again went on an adventure, and this time we decided to conquer Norway and its snowy hills covered with picturesque cottages.

Our journey started on Prague’s airport, where we had a flight to Oslo and from there we took a long ride by car (5,5 hours) until we arrived in Ustaoset, Buskerud, where we stayed for a week on our colleague’s cottage. (Many thanks again to Honza for the invitation and the hospitality!).

There was really no shortage of snow. Ustaoset is 990m above the sea level and is the finish spot for the cross country ski event Skarverennet. So the scenery was great and view from cottage’s living room, even better.

Due to coming storm Dennis the weather was not ideal especially in the beginning of our week. So the first day we spent working and making plans for the upcoming days.

When the weather got better, there was a plenty of options what we could do!

Kiting

Probably the most tempting activity we all wanted to try was snowkiting. 
Since most of us are complete beginners, we had our instructors nearby to teach us the basic techniques to operate the kite and help us. 

Kiting is certainly not one of the easiest sports you can do, in the beginning, you spend quite a bit of time untangling your kite, because it tends to get out of control a lot and you have to put it in the air over and over again.
It frankly requires a bit of patience, but once you get into it, you will love it. 

It was a great feeling to chase winds on a snowy plains either on skies or snowboard.

A little different camping

Since we saw a chance to get the true nordic night experience firsthand, we took the challenge and a few of us decided to spend a night outside. 

We did have all the necessary equipment and experienced instructor to guide us through. So the fun could begin!

We had to start building two tents early in the afternoon to get things done in time. 
KP for aurora borealis was 4 at that time, so there was a little chance, but we still secretly hoped to catch it. 
A few hours later, the two tents were standing, tops of mountains started to get a pink tint and we were about to call it a day, cooked dinner and went to a bed early.

Nevertheless, since we know how to command weather, we did see aurora borealis in the end. 
In the morning, still in a shadow of the past night, green as an emerald, just as we all pictured it. :)

Skiing and the surprise

Norway has quite a few skiing resorts and the one we went to was Geilo. It happens to be the 5th best resort in Norway, located just a few kilometres from Ustaoset. The first impression was half empty slopes with a fresh powder snow, so actually really nice.

After we enjoyed a full day of sunny weather in the mountains, we joined an evening surprise, which was a night sledding and a hot bath outside for the more venturesome among us.

Here is a little sneak peek on how we pulled it off in the end:

Update: 28th of May 02:00 p.m. UTC

SpaceX launch of NASA Astronauts is postponed over the weather

Thunderstorms and light rain caused by Tropical Storm Bertha were the reason why mission Commercial Crew Demo-2 was aborted only 17 minutes before liftoff.

The Next attempt is scheduled for Saturday, 30 May at 7.22 PM UTC (3.22 PM EDT).

Although chances for success look similar, stormy weather with cloud cover is predicted, upper winds, which can drive thunderstorms to the coast, might be better. On the day of supposed launch, upper winds were moderate (13 kt/24 km/h), on Saturday will be light (4kt, 8 km/h).

In case the launch will be postponed again, the backup launch window for Falcon 9 is available 31 May at 7 PM UTC (3 PM EDT), with the same probability for success.

Update: 27th of May 01:00 p.m. UTC

The SpaceX first-ever crewed spaceflight is scheduled to take off from Cape Canaveral in Florida later today as a mission Commercial Crew Demo-2.

The launch is currently set to 08:30 p.m. (4:33 PM EDT) from Kennedy Space Center, however the weather conditions are not looking very favorable. There is currently a 50% chance that clouds and stormy weather will delay the proceedings due to violating the safety guidelines.

The Crew Dragon capsule will initially spend 19 hours orbiting the Earth till reaching the International Space Station on Thursday.

If the launch ends up to be postponed, another opportunity to send the capsule into the orbit will be on Saturday 30th May.

https://www.windy.com/upload/5ece9129f8e856001d015140?radar,28.229,-81.088,9,internal

Update: 14th of May, 10:00 p.m.

VongFong (Ambo) is moving westward across Samar Island with position 12.5N 123.6E and maximum sustained winds 74 km/h (065 KT) and gusts 92 km/h (080 KT). Typhoon has slightly weakened, however is still striking the island with extreme rainfall and typhoon-force winds.

Typhoon should continue loosing its strength further with a position at 13.5N 122.3E in the next 12 hours.

An estimated number of 200 000 people needs to be evacuated from their homes to avoid life-threatening flooding and landslides, but local authorities are already facing problems with finding shelters along with pandemic situation.

Update: 14th of May
Tropical typhoon VongFong with the current position near 12.2N 125.3E and maximum sustainable winds 185 km/h (100 KT) and gusts 231 km/h (125 KT) has arrived to Philippines.

The upcoming movement is near 12.8N 123.7E with winds 166 km/h (090 KT) and gusts 203 km/h (110 KT) and going deeper into Bicol regions and Visayas in the next 24 hours. The predicted scenario is VongFong striking Luzon during the Friday night, the largest island of the country, with heavy rains.

The situation is even more difficult since the country is under COVID 19 lockdown, so potential emergency efforts could be complicated by a strict social distancing of the evacuated citizens.

Update: 13th of May
The pacific typhoon season of 2020 has officially began, during the past few days a new tropical typhoon has developed in the Philippine Sea and was given an international name Vongfong, locally known as Ambo. The initial tropical depression was indicated on Sunday and progressed into Tropical Cyclone Formation Alert later on.

The former tropical storm is likely to reach Philippines ports on Thursday 14th of May and will most likely affect the Catanduanes Island with heavy wind and rainfall.

Vongfong is currently moving near 12.0N 128.5E with maximum sustainable winds 129 km/h (070 KT) and gusts 157 km/h (085 KT) with possibility of strenghtening as it gets closer to the northern ports.

Warning for heavy rainfall, landslides and flooding has been issued for the affected areas. Wind threat can also cause corrupting electricity, knocking down trees and roadblocks.

https://www.windy.com/upload/5ebc2b1f6d85e3001d6ecce9?satellite,16.220,123.871,5,internal

Update: 7:00 a.m. UTC 9th April

TC Harold is on its path to completely weaken and getting torn apart by a jet stream over the South Pacific open waters.
After his rampage track through the pacific nations Vanuatu and Fiji, Harold intensified to Category 5 hurricane and passed Tonga on Thursday 9th of April.

The current movement in the last 6 hours is 23.8S 172.1W with approximate position 545 NM Southeast of Suva, Fiji and wind speed 102 kts (188km/h) to 127 kts (235km/h). Cyclone is moving away from any land areas.

Update: At 9:00 p.m. UTC 8th April, Harold was moving at 22.5S 174.3W located approximately 408 NM Southeast of Suva, Fiji.

Cyclone slammed Tonga with gusts 150km/h, which were recorded near the Nuku'alofa, the Tongan Capital. However the center of Harold happened to pass about 100 miles south of Tongatapu and Eua islands and saving them from the most severe conditions.

Harold should continue to weaken in the next days over the South Pacific waters.

Update: At 5:00 p.m. UTC on April 8th

STC Harold category 4 hurricane is aiming towards Tongatapu and 'Eua tonight. High swells up to 20 ft (6 m) and tides with height of 1.87mm. The most severe conditions are expected to occur overnight and in the morning.

The current position is near 21.1S 176.9W. Cyclone is predicted to move 90km south-west of Nuku'alofa and 100km west south-west of 'Ohunua 'Eua Thursday morning.

Update: At 8:00 Zulu (8:00 a.m. UTC) on April 8th

Harold (category 5 hurricane) slams into the largest island of Fiji, Viti Levu and the capital city Suva, which has suffered with heavy flooding and buildings being demolished or damaged.

Tropical cyclone is moving near 19.4S 178.7E with maximum sustained winds 120 kt (222.24 km/h) gusts 145 kt (268.54 km/h).

Cyclone is expected to be moving to Tonga in the upcoming 48 hours, therefore a warning has been issued for extreme high tides on Thursday and Friday.

Update: At 10:00 a.m. EDT (15:00 UTC) on April 7th
Harold was issued with category 3 hurricane with maximum sustained winds 110 kt (203 km/h).
The cyclone centre was located 17.4S 174.0E and moving east-southeast to Fiji.

In the next 24hrs the maximum sustained winds should remain the same 110 kt (203 km/h) and gusts 135 kt (250 km/h).

The landfall of Harold is predicted on 8th April at 8:00 p.m. EDT (00:00 UTC) and move to the southeast near Tonga.*

Update: At 8:48 p.m. VUT Tuesday 7th April (9:48 a.m. UTC)

Tropical cyclone Harold [927hPa] is moving 17.1S 172.6E. This is about 430km east-northeast of Erromango and 465km east of Efate, which is part of Shefa Province in Vanuatu.
The current estimated maximum sustained winds are 110 kt (203 km/h) and gusts 135 kt (250 km/h).
Further predicted movement in the next 12 hrs is 18.5 South 175.9 East. Check out the latest Advisory at metoc.navy.mil*

Update to 6.4.2020 afternoon CET (evening in Vanuatu)

Tropical cyclone Harold arrived to Vanuatu with flooding surge, hurricane-force winds and heavy rainfall. Morning local time, the cyclone Harold reached Espiritu Santo, the largest island of Vanuatu with population of 40 000 people. And later moved towards the Pentecost Island.

As the cyclone is expected to move through the islands of Vanuatu, the warning has been issued. Heavy swells and high sea wind could be anticipated for coastal and open waters of Vanuatu. People are strongly adviced to avoid affected areas and not to go out on sea.

On Wednesday 8th of April, the cyclone Harold is expected to pass near Viti Levu, the Fiji's most populated island or just its southern parts.

The heavily affected area is Sanma province, the reported damages have been destroyed or lost buildings.

Date: 5.4.2020 (evening CET)

A tropical cyclone in the South Pacific Ocean named Harold is expected to hit Vanuatu in the upcoming hours. As of Sunday evening CET, the cyclone is now moving near the northern parts of Republic of Vanuatu is likely to intensify as it approaches the islands.

Heavy rain, strong damaging winds with surge flooding are expected. The current maximum sustained winds are expected to be 190km/h and could raise to 220km/h once it gets closer.

Harold can also target near or south of Fiji later this week, but the details are still uncertain.

The cyclone has formed last Wednesday in the area of Solomon Islands and Papua New Guinea.

Residents of Sanma, Penama and Malampa provinces should take proper actions to prepare themselves for heavy rainfall and hurricane-force winds.

Amid the COVID-19 measurements, Copernicus monitors a 10% per week reduction in NO2 surface concentrations since mid-February.

While the question of improved air quality is a secondary concern with the world facing the COVID-19 crisis, satellite observations detected abrupt changes in activity levels in Northern Italy, where dense surface observation of the pollutant nitrogen dioxide (NO2) shows a gradual reduction trend of about 10% per week over the last four to five weeks.

The Copernicus Atmosphere Monitoring Service (CAMS), implemented by the European Centre for Medium-Range Weather Forecasts on behalf of the European Commission, provides daily analyses of hourly concentrations of regulatory air pollutants, which can serve as “ground truth” to assess quantitatively and in more details the changes in concentrations identified from satellites and attributed to the effects of COVID-19 measures across the world.

The CAMS regional air quality analyses come in the form of hourly gridded maps and are obtained by combining satellite observations, surface in situ observations and numerical modelling. Taking the point covering the city of Milano, the hourly timeseries of surface concentration of NO2 since January 1st is shown below.

While no clear trend is visible over the first five weeks of the year, a decreasing trend can be seen starting during week 6 and continuing to date. Average NO2 concentrations were around 65 mg.m-3 in January, 45 mg.m-3 in February, and around 35 mg.m-3 for the first half of March. The linear decreasing trend on the daily average since week 6 is of the order of -4 mg.m-3 per week. Similar decreasing trends are found for other cities in Northern Italy, such as Torino or Bergamo. In the East, there seems to be rather a step change: in Bologna, concentrations were on average around 30 mg.m-3 in January and are on average around 15 mg.m-3 since the beginning of February (35 mg.m-3 and 15 mg.m-3 for Venezia).

“What the satellite observes is proportional to the vertically integrated amount of pollutants from the ground up to the top of the atmosphere”, explains Vincent-Henri Peuch, Director of Copernicus Atmosphere Monitoring Service. “This is quite different from the concentrations at the surface and even more so from the emissions. Given these limitations, it is quite remarkable that a signal of decreasing activity levels could be detected. This shows the extent of the measures taken by Italy.”

NO2 is a short-lived pollutant. Once emitted, it will stay in the atmosphere generally less than a day before being deposited or reacting with other gases. This means that this pollutant remains fairly close to where it has been emitted. Most of its emissions sources are located at the surface and are generated by human activities such as traffic, energy production, residential heating, industries, etc. The sources vary greatly during the day, as well as depending on the day in the week and the month. It also depends on factors such as weather, as a cold spell will trigger increased residential heating and energy demand.

CAMS is continually monitoring the air quality over Europe and on a global scale, providing the data to most leading websites and smartphone applications such as Windy, The Weather Channel, Breezometer or Plume Labs.

What is CAMS?

CAMS is implemented by ECMWF on behalf of the European Commission.
CAMS regional air quality analyses are operationally produced by a consortium of contractors led by Météo-France and INERIS (France). These partners rely on surface air quality observations provided by the European Environment Agency, which gathers them from each individual country.

The CAMS regional air quality analyses come in the form of hourly gridded maps and are obtained by combining satellite observations, surface in situ observations and numerical modelling that mimic the laws of physics and chemistry in the atmosphere. The data collected is of high quality and can be considered as “ground truth”. The main limitation of this dataset is that it cannot account for fine spatial variability and local effects that occur within a few meters to hundred meters near a source, like a road segment with heavy traffic or a power plant chimney stack. The data is representative of the average background values over a grid with a scale of 10km by 10km. The data can be obtained openly and freely from CAMS’ Atmosphere Data Store.

Can satellites really observe air pollution at the surface?

The European Commission’s Copernicus Sentinel-5 Precursor (S-5P) TROPOMI instrument benefits from an unprecedented spatial resolution of 3.5km x 5km, which allows to see fine maps of a number of air pollutants such as NO2. Satellite observations have however some limitations on the level of detail at which they can be used for monitoring air pollutants.

Firstly, they make their measurements from satellites in Low-Earth-Orbit and provide only one measurement per day for each location on Earth: for example, the overpass time of S-5P is 13:30 Mean Local Solar time. Second, the physics of the atmosphere is such that for pollutants like NO2, measurements are not possible or significantly degraded in the presence of clouds and of fine particles suspended in the air (aerosol). During the winter in Europe, this means that only about 25% of the data can be used.

To overcome this issue, observations can be averaged over longer periods of time (typically a running average of 10 days), in order to have at least one or two measurements for each location in each average period. Finally, and most importantly, what the satellite observes is proportional to the vertically integrated amount of pollutants from the ground and up to 10 km (tropopause); this is obviously different from the concentrations at the surface, let alone the emissions by human activities. Given these limitations, it is striking that a clear signal of decreasing activity levels could be detected. Over Europe, high-quality surface observations are made by each individual country and gathered by the European Environment Agency in Near-Real-Time. These observations can serve as “ground truth” to assess the reality of the signal detected by satellite.

What is the situation in other parts of Europe?

In other parts of Europe, the detection of statistically robust trend is yet more challenging, as shown below for some capitals in North-Western Europe. Weather-related episodes of high (between weeks 3 and 4; week 6) and low NO2 surface concentrations are the main features that can be seen.

What are the plans of Copernicus for monitoring emissions using satellites in the future?

As part of the Copernicus programme, CAMS is currently developing a capacity to derive emissions directly, using further advanced modelling techniques. An essential ingredient for this will be the new generation of satellites monitoring air pollutants. These will be embarked on geostationary platform and will provide hourly observations over selected part of the world.

The Korean Aerospace Research Institute’s Cheollian 2B satellite, which was launched into orbit aboard an Arianespace Ariane 5 rocket on February 18th, hosts the first instrument of this kind, GEMS (Geostationary Environment Monitoring Spectrometer); scientifically useful data covering parts of Asia is expected to be available at the end of this year. Similar instruments are planned over the US (TEMPO) and Europe. As part of Copernicus, the Sentinel-4 instrument onboard Eumetsat’s Meteosat Third Generation will launch in late 2022 or 2023. Sentinel-4 will be the backbone for the planned emissions information service of CAMS, which will be operated by ECMWF.

Valid: Thu 09 Apr 2020 06:00 to Fri 10 Apr 2020 06:00 UTC
Issued: Wed 08 Apr 2020 19:29
Forecaster: PUCIK

A level 2 was issued across eastern Iraq and western Iran mainly for large to very large hail and damaging wind gusts.

A level 1 was issued across Iraq, eastern Syria and southeastern Turkey mainly for large hail and severe wind gusts.

A level 1 was issued across eastern Algeria mainly for large hail and severe wind gusts.

SYNOPSIS

Stable weather conditions are forecast across much of western and central Europe under the influence of an extensive high pressure system centered over the Northern Sea. A cold front is forecast to cross the Baltic Sea and continue moving SE-wards across Poland, northern Ukraine and Belarus. Due to the dry conditions, the front will be mostly devoid of any precipitation.

More active weather pattern, at least concerning the convective storms, is forecast across southern parts of the forecast domain. Isolated to scattered storms are forecast ahead of an ill-defined trough over Spain and in northwesterly flow across northern Africa.

More widespread thunderstorms are anticipated over Turkey and parts of the Middle-East, under the influence of a deep mid-tropospheric low centered over Cyprus and southern Turkey.

DISCUSSION

SE Turkey, E Syria, Iraq and Iran

Ahead of the deep mid and upper tropospheric low, strong southwesterly flow is simulated over the region, increasing from southeastern Turkey towards Iran. Especially over Iraq, moist airmass combined with steep-lapse rates exceeding 7 K/km and 0-6 km shear around 25 m/s will create favorable conditions for severe convective storms. Given the strong shear, any initiating storm may become supercell with threat of large to very large hail and damaging wind gusts.

However, initiation remains questionable over the area of the best CAPE / shear overlap and NWP simulates only isolated storms. Thus, it seems that the hail threat will be more prominent than the wind gust threat.

Towards Iran and Turkey, models are more consistent regarding scattered to widespread initiation of the storms. Over Turkey, 0-6 km shear around 15 m/s will allow for multicells or some marginal supercells with threats of large hail or severe wind gusts.

E Algeria

Isolated to scattered storms are forecast in northwesterly flow, strongly increasing above 3 km. While 0-6 km shear will reach up to 25 m/s, 0-3 km shear will stay mostly below 10 m/s over the region.

Given EL mostly around 500 hPa and skinny CAPE profiles, it is questionable whether the shear confined to above 3 km will aid the storm organisation or mostly only enhance the dry air entrainment through the updrafts. At least few stronger updrafts may become well organised with primary threat of large hail and a low-end Lvl 1 is introduced.

Valid: Sat 04 Apr 2020 06:00 to Sun 05 Apr 2020 06:00 UTC
Issued: Fri 03 Apr 2020 20:35
Forecaster: GATZEN

• A level 1 has been issued across the Aegean Sea region mainly for excessive precipitation and large hail, tornadoes and severe wind gusts.

SYNOPSIS

A European polar trough is filled with cold and dry air masses that expand into most of the Mediterranean. A trough across the west Mediterranean moves east and starts to cut off as mid-level ridging increases across Central Europe. Ahead of the progressing Mediterranean trough, a strong south-westerly flow affects the Aegean and Turkey that turns south-east when the trough center passes late in the period.

DISCUSSION

An elevated mixed layer advects northward ahead of a cold front. At low levels, moisture is limited and given rather low temperature in the boundary layer, large CIN is present. However, along a mid-level front that moves eastward late in the period, weakening CIN is expected to extent into the moist air mass close to the cold front, and some weakly-capped CAPE can develop.

However, most CAPE will still be elevated as indicated by all available models. Therefore, chances of severe wind gusts and tornadoes are reduced.

Strong vertical wind shear is present along the cold front and overlaps with CAPE especially across the Aegean Sea. Curved hodographs indicate a good potential for rotating storms if sufficient boundary-layer rooting takes place.

Therefore, a few well-organized storms are not ruled out, capable of producing large hail. Severe wind gusts and tornadoes are not ruled out. Given the limitations discussed above, the overall potential is quite low, though.

Most significant severe weather threat will be excessive precipitation, though. To the north of the trough center, south-easterly flow advects moist air masses into the Aegean region. Latest models suggest neutral lapse rates, and non-convective precipitation is forecast, although some embedded storms may develop.

Main threat is along the western Aegean coasts due to upslope flow. Due to the mostly non-convective nature of precipitation, a level 1 has been issued.

@bodja-0 Hello, Route planning on phone is limited, so is the option to change units. Full version of this feature is on desktop.

@raliclo @nupur-risbood Hi, once uploaded KML file can be share via the share option. It does not work for you?

@jenca If you mean frequency, then you should send data in 5min intervals.

@Gkikas-LGPZ @Sadac2 It could be in a different currency.

@Sadac2 Hello, please follow the steps in this article - https://community.windy.com/topic/11832/what-to-do-if-you-can-t-access-your-windy-premium-features

@bmwonthemove Hi, thank you for spotting it. :)

Cyclone Nisarga India 2020

https://www.windy.com/upload/5ed7547c18b9f0001d7b3c59

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Update: 4th June 00:00 UTC

TC Nisarga is now moving northeastwards towards Nashik and continues to weaken, the current sustainable winds are 75km/h (40 KT). Movement speed was 27 km/h (14 KT) in the last 6 hours.

Dhule and Nandurbar districts may experience heavy rainfall and gusty winds.

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Update: 3rd June 3:00 p.m. UTC

Tropical cyclone Nisarga, the equivalent of a Category 1 hurricane, battered western India with torrential rainfall and strong winds. It is also the first cyclone to strike the city of Mumbai in history.

The landfall itself did not cause major damages, despite the winds speeds more than 100km/h (53 KT) as it reached the land.

Moving further inland, cyclone lost its strength quickly and was downgraded to a deep depression. However the next few hours are still crucial.

Cyclone is now moving at 25 km/h (14 KT) with position 19.6N 74.2E. east of Mumbai, maximum sustainable winds are 60 km/h, gusts 90km/h (48 KT). Expected movement in the next 12 hours is 21.0N 75.8E.

Update: 3rd June 9:00 a.m. UTC

Nisarga has made a landfall around noon local time near Maharastra’s Raigad district with stronger maximum sustainable winds than expected 140 km/h (75 KT) and gusts 166 km/h (90 KT).

However the landfall is far from gone, it will take 3 hours to complete, the current position is 18.3N 73.3E, cyclone is located approximately 65 NM south of Mumbai.

The cyclone will move gradually over the land, the next expected direction is 19.5N 74.5E towards Panvel, Maharastra. Winds speeds should weaken to 92 km/h (50 KT), gusts 120 km/h (65 KT).

Update: 3rd June 5:00 a.m. UTC

Cyclone Nisarga has been moving at 13 km/h (7 KT) in the past 6 hours and its position is 17.2N 72.1E, 130km south-southwest of Alibagh, town in Maharashtra’s Raigad district.

The storm has intensified to maximum sustainable winds 110 km/h (59 KT) and gusts 120 km/h (64 KT).

Predicted landfall is today between 12pm and 3pm IST just the south of Alibagh. Heavy rainfall is expected with a storm surge of about 1-2 metres height.

This will affect low laying areas of Ratnagiri district mainly and Mumbai, which is on the path of the cyclone.

Update: 2nd June 9:00 a.m. UTC

A deep depression has intensified into a cyclonic storm in the Arabian Sea and is predicted to become a severe cyclonic storm named Nisarga in the next several hours. Storm has been moving at 11 km/h (5 KT) northwards in the past 6 hours.

The current maximum sustainable winds are 70 km/h (37 KT) and gusts 90 km/h (48 KT) with a position LAT 16.0/LON 71.5.

The strom could possibly bring a devastating winds of 110 km/h (59 KT) and gusting to 120 km/h (64 KT).

The expected landfall is either on Tuesday night or early Wednesday morning 3rd of June over Mumbai, north Maharashtra and Gujarat coasts.

https://www.windy.com/upload/5ed7547c18b9f0001d7b3c59?satellite,15.739,72.993,7,internal