Storm Forecast

Storm Forecast
Valid: Sun 28 Sep 2014 06:00 to Mon 29 Sep 2014 06:00 UTC
Issued: Sat 27 Sep 2014 23:32
Forecaster: PUCIK

A level 1 was issued for E Spain and the Balearic Sea mainly for excessive precipitation.

A leve 1 was issued for NW Algeria mainly for large hail, severe wind gusts and excessive precipitation.

SYNOPSIS

During Sunday, a large ridge will stretch from the Mediterranean towards Central Europe, with troughs on the either side - one over Iberia and another, deep one, over Turkey. Towards the north, lower amplitude, strong westerly flow will be observed, with deep low pressure system affecting Norway and Sweden.

Regarding DMC activity, most of Europe will be under stable and dry conditions, apart from Iberia and the Balearic Sea, where scattered to widespread tstm activity is forecast.

DISCUSSION

... E Spain and the Balearic Sea...

On the forward flank of the trough, mid to upper tropospheric flow will turn southerly, advecting steeper lapse rates from N Africa atop the warm and moist boundary layer of the sea. As a result, marginal to moderate CAPE build-up is forecast. Models reveal several subtle short-waves crossing over the sea to the north, as well as the surface cyclogenesis is forecast. To its north, easterly surface flow will impinge on the coastline, creating favorable setup for widespread convective initiation. It is likely, that in the environment of low CIN, a large cluster, perhaps an MCS will form. Relatively slow storm motion, along with high chance of cell training as convection backbuilds towards the moist easterly flow, will provide favourable setup for several excessive precipitation events. Because of the model inconsistency regarding the MCS track, Lvl 1 seems to be sufficient choice at the moment.

... NW Algeria ...

Compared to Spain, steeper lapse rates, higher CAPE values and also stronger DLS will likely allow for some well organised DMC. Here, besides the excessive rainfall threat, large hail and severe wind gusts may occur as well, especially if supercells manage to form.

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