Avisos, Alertas e Previsões oficiais - Setembro 2014

SpiderVV

Staff
Registo
26 Ago 2010
Mensagens
8,287
Local
Portalegre (400m)
Aviso amarelo para os distritos do Sul para amanhã devido a aguaceiros e possibilidade de trovoadas.

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david 6

Super Célula
Registo
22 Jan 2013
Mensagens
8,883
Local
Fajarda - Coruche(57m)
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A level 2 was issued for NE Morocco and N-Algeria mainly for excessive rain and large hail.

A level 2 was issued for the S-Aegean Sea and Crete mainly for large hail, severe wind gusts, excessive rain and an isolated tornado.

A level 1 surrounds both level 2s for a lesser severe risk.

A progressive trough north of Scotland (26th, 06Z) crosses Norway, Sweden and most of Finland from west to east until 27th 06Z. A pronounced high is placed to the south and keeps regions from France to the W-Mediterranean stable. A strong cut-off evolves over SE Europe with another but weaker one over Portugal.

... N-Algeria to S-Spain ...

A quasi-stationary boundary, trapped along the Atlas Mountains, keeps BL moisture high. A confined area of 500-1000 J/kg MLCAPE and 15 m/s DLS with daytime heating assist in scattered thunderstorms with large hail the main risk. Clustering storms along/south of the Atlas Mountains could also bring excessive rain with flash flood problems. Weak positive thickness advection lowers the risk for thunderstorms from E to W during the night. Effective PWs of 15-30 mm, slow moving storms, dry soil and anticipated scattered to widespread CI increase confidence in a more serious flash flood risk. Hence the level 2. Towards Spain, less PWs and CAPE lower the severe risk and we kept this area in a broad level 1.
 
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Miguel96

Cumulonimbus
Registo
13 Fev 2011
Mensagens
3,128
Local
Espinho, distrito de Aveiro
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Duarte Sousa

Staff
Registo
8 Mar 2011
Mensagens
5,994
Local
Loures
A level 1 was issued for NW Portugal mainly for an isolated large hail event.

SYNOPSIS

Big high arches upward over S/CNTRL Europe. Flanking troughs bring thunderstorms to the Iberian Peninsula, the Aegean Sea and Turkey. Active cold sector convection occurs over Estonia and east of Finland.

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... Strait of Gibraltar and Portugal...

Quasi-stationary warm front is focus for BL moisture pile-up over the Alboran Sea. Overlap of 1 kJ/kg MLCAPE and 20 m/s DLS exists all day long. Despite weak short-waves, no distinct forcing is seen, so CI occurs mainly due to mesoscale forcing (e.g. outflow boundaries) or with offshore moving storms from N-Morocco and NW Algeria. Large hail and severe wind gusts will be the main risk although excessive rain could become another risk for far SE Spain, if storms move ashore (PWs of 35-40 mm).

An upper low is placed NW of Portugal. Onshore flow advects marine layer well inland beneath cooler mid-levels. 500-800 J/kg MLCAPE and 10-15 m/s DLS result in a few better organized multicells with large hail the main risk. An isolated waterspout event is possible along the coasts of Portugal. We issued a broad 15-% lightning area for elevated convection during the night. Meager CAPE and weak shear preclude organized convection.
 
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