Sub-Tropical High Begins Northward Migration, Extends Into Italy, Turkey, Poland Next Week

As we enter spring’s 2nd half we firstly look back at March.

Credit: Michael Ventrice

Credit: Michael Ventrice

As we enter April, warmth matures over North Africa as the scorching heat core begins to migrate northward to the Sahara. During winter, the sub-tropical ridge we worship throughout the Med each summer, starts off just above the equator and as the sun angle rises and the incoming solar radiation increases, so the subtropical high strengthens and migrates north.

Earth_Global_Circulation_-_en_svg

This semi permanent feature from late May through early September starts spring by baking the African Sahel region in temperatures between 40-48C where as the Sahara is in the low to mid 30s. However, by early summer, the position of the subtropical high is such that the focus of extreme warmth and cloud free sky is over the Sahara while it’s cools with the rainy season over the Sahel. By late July, the subtropical ridge is generally at it’s furthest north position providing hot, dry conditions to North Africa and the Med Sea Basin.

Currently, it’s too early and too far south for any major heat at our latitude but lobes of this high can push warmth north, all depending upon the upper setup across Europe.

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Lobes of this heat flex north-south across the Med and into southern Europe.

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As your probably well aware, the UK sits in the fight zone between hot to the south and cool to the north during the summer months. Sometimes we enjoy a further north positioned subtropical ridge, sometimes we see little influence with a further south jet bringing more cloud and rain. Summers of 2013 and 2014 saw more Azores ridge influence which shot temperatures to 28-30C as far north as Scotland where as last year, the Azores ridge was largely nowhere to be seen and in fact we endured some of the coolest July days on record.

When the subtropical ridge is at it’s further north, the jet stream is weak and often just north of the UK keeping us on the warm side but we’re close enough that the jet can go either way.

If you’ve been reading my articles and watching my videos for a few years, you’ll know the ENSO, NAO/AO and solar state all impact the intensity, position and behaviour of the summer subtropical ridge. Sometimes it’s strongest on the Bermuda side while other times the Azores side.

This weekend on into next week sees some real heat pushing off Africa and into Italy, Greece and Turkey as low pressure sinks into Iberia.

This morning started off rather cold in Highland Scotland with a minimum of -7.6C at Altnaharra whereas down in southern Spain, it was the warmest day of the year yesterday with 29.7C recorded near Malaga. It also appeared to be be warmest in Europe too.

Credit: Meteoceil

Credit: Meteoceil

Sizable temp contrast over the UK yesterday.

Credit: Meteoceil

Credit: Meteoceil

Certainly a big contrast between Spain’s northwest coast where winds blow and air temperature reflects water temperature.

Credit: Meteoceil

Credit: Meteoceil

Tricky upcoming weekend forecast as a front initially pushes across NI and Scotland tomorrow but then as low pressure forms, the front stalls and becomes and pivots north Sat into Sun. As winds veer SE, warmer air building over the near continent looks to get pulled into the southern UK as shown yesterday. Wind direction and sunshine will be crucial to temperature, especially Sun-Mon.

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

With the developing low sliding SE into Iberia and France, it’s not looking as mild for northern France as it did yesterday but this allows hot Saharan air to lift into south and southeast Europe where the first 30s of the year are likely for some.

Credit: AccuWeather Pro

Credit: AccuWeather Pro

We can hope for a little tongue of warmth wrapping around the low to draw on 19-21C air into SE England Monday.

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

Credit: AccuWeather Pro

The warmth isn’t confined to Europe’s Med coast countries but in fact the core of warmth appears to centre over the interior Balkans with even Poland enjoying mid 20s towards next weekend.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

See today’s video.

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