19-07-2024 00:50 | Estofex | m.b.t. 20-07-2024 t/m 21-07-2024
Extended Forecast
Valid: Sat 20 Jul 2024 06:00 to Sun 21 Jul 2024 06:00 UTC
Issued: Thu 18 Jul 2024 22:50
Forecaster: TUSCHY
A level 1 was issued across France into Belgium and Luxembourg mainly for severe gusts, a few large hail events and heavy rain. The risk turns more into an isolated strong to severe gust risk towards far W Germany.
A level 1 was issued across SE Germany to W Hungary for heavy rain.
A level 1 was issued across the Balkans and into Romania mainly for large hail, severe gusts and heavy rain.
A level 1 was issued for W Georgia mainly for heavy rain.
SYNOPSIS
Prolonged blocking pattern over S/E Europe weakens and turns into a higher latitude blocking event with a strengthening Scandinavian anticyclone. This pattern shift is forced by an healthy anticyclone next to the Azores and an E/SE ward drifting extensive upper trough over Iceland, which sends a strong impulse/IPV maximum towards the Bay of Biscay and later-on deep into France (before starting a cut-off process, which is beyond our forecast scope).
This new pattern turns the flow more westerly from France into Italy and still highlights an ongoing wave flux/wave train which points towards the Mediterranean.
Numerous residual upper troughs over W Russia and Turkey remain in place and support regionally unsettled conditions.
Not many surface fronts to talk about as the Atlantic fronts remain well W but impact NW and far W Europe during the forecast. An extensive prefrontal convergence zone could evolve over France and serve as focus for scattered to widespread CI.
DISCUSSION
... France, Benelux into W Germany ...
Downstream of the approaching trough, a plume of moist air advects from France N/NE towards the North Sea. The trough approaches from the NW, so not much EML advection from the S is forecast. Some regional steeper lapse rates from the Pyrenees and Spain advect into S/SE France during the day but otherwise neutral lapse rates keep CAPE magnitude in check.
Most aggressive CAPE build-up occurs between the Pyrenees and the Massif Central with MUCAPE in the 1000-2000 J/kg range with local higher peaks next to the Pyrenees. Somewhat steeper mid-level lapse rates also advect into NE France/Benelux with MUCAPE around 1500 J/kg.
Mid-level winds increase from the W with DLS pushing into the 15-20 m/s range towards SW/CNTRL France. Further E shear remains weak and oscillates around 10 m/s until the evening.
Expect scattered CI during the late afternoon along a prefrontal convergence zone, which runs from the Massif Central vicinity towards Belgium. Rather disorganized convection brings some hail and severe gusts next to heavy rain (PWs of 35-40 mm). A mixed BL points to growing cold pools and clustering convection with regionally enhanced severe gusts over E-CNTRL into NE France. A large hail risk could materialize towards the Massif Central, where shear becomes more favorable for effective hail growth.
During the night the approaching cold front from the Bay of Biscay sparks new storms over SW France, which could take profit of stronger 0-3 km and 0-6 km shear (15 and 20 m/s respectively) with a few severe gusts and isolated hail issues. This activity shifts E during the night with isolated severe.
A concern exists along the Massif Central vicinity as this area could see repeated thunderstorm development all night long with heavy to isolated excessive rain. QPF signals in numerical guidance do not yet justify a level 2 but this area has to be monitored in future runs.
A few elevated nocturnal storms spread N into the W part of the North Sea but should stay sub-severe.
(alleen de voor NL en aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Hagel(-schade) | Onweer/blikseminslag | Verwachtingen/waarschuwingen | Wateroverlast/(zware) neerslag | Wind/storm (-schade)
