A sudden warming phenomenon could cause a cold snap in March as forecasters warn of a bitter blow before the spring warmth takes hold.
A major Sudden Stratospheric Warming (SSW) is likely to occur tomorrow – bringing milder but potentially cold conditions.
The weather phenomenon may trigger a chain of changes that could bring sustained colder weather in March.
Net Weather forecasters say high pressure building over Scandinavia will act as a shield for incoming Atlantic low pressures.
A sudden warming phenomenon could cause a cold snap in March as forecasters warn of a bitter blow before the spring warmth takes holdWXCHARTSThe high pressure is expected to remain in the northern quadrant to the UK which will bring drier conditions this month.
While a more southerly flow maintains milder conditions, if that does shift to the east, it will feel colder.
Forecaster Nick Finnis said: “Every spring, the stratospheric polar vortex transitions from its westerly wintertime state to its easterly summertime state due to seasonal changes in incoming solar radiation, an event known as the ‘final stratospheric warming’ (FSW).
“Normally the FSW takes place in April, so by the time the reversal works down to the troposphere and increases the chances of high latitude blocking, much of the higher latitudes of the northern hemisphere are already warming up with the longer days and higher sun angle.
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“However, in March there is still deep cold air at higher latitudes to tap into, so following an early March SSW, any high latitude blocking that may develop could push cold enough air south or southwest across Europe to bring below average temperatures and wintry conditions.”
Weather expert MetJam suggests the SSW will hit tomorrow but expects conditions to remain mild.
Writing on social media, he said: Another sudden stratospheric warming (SSW) is due to occur from tomorrow morning onwards which looks like it might hamper some efforts for things to turn milder.
“Ensembles look pretty average at the minute so not sure on the prospects of any real cold, especially as we are in March.”
The weather phenomenon may trigger a chain of changes that could bring sustained colder weather in March
Net Weather
Finnis has urged caution over the potential plummeting temperatures, as “its not straight forward to assume a SSW of FSW will lead to cold weather”.
He said: “On average, a major Sudden Stratospheric Warming does lead to a Negative North Atlantic Oscillation (-NAO) which is often associated with blocking high pressure near or over Greenland – which forces the Atlantic storm track further south and also causes cold air to push south into Europe, including the UK.”
“Longer range modelling, EC46 for example, does forecasting high latitude positive height anomalies to the north from Scandinavia to Greenland, indicating potential for blocking high pressure in this area between mid-March and the beginning of April,” he added.
A sudden warming phenomenon could cause a cold snap in March as forecasters warn of a bitter blow before the spring warmth takes holdWXCHARTS
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