DIOS MIO, LAS PRIMERAS FOTOS..... http://forums.infoclimat.fr/topic/58836-monstrueux-14-juillet-en-avesnois-et-proche-hainaut/
DISCUSSION... Finland, Karelian Republic, Kola penninsula ...With the dynamic effects of the approaching short wave trough at mid and upper levels of troposphere, in the exit region of the jet-streak, surface low is expected to deepen with central pressure predicted to drop below 1000 hPa (ECMWF even simulates the pressure to drop below 994 hPa). This surface low will travel northwards and in its warm sector, very warm and humid airmass will be advected from south/southeast. MLCAPE values should reach 1000 J/kg in the warm sector, locally even more, especially in the southern parts of the region.Due to the strong flow at the lower levels, with windspeeds over 20 m/s both at 850 and 700 hPa, especially towards afternoon hours, wind shear will be strong and confined mostly to the lower levels of troposphere (with 20 m/s flow at 500 hPa and 25-30 m/s at 300 hPa level). Wind shear in the lowest 3 km will attain values up to 25 m/s and up to 15 m/s in the lowest 1 km. Furthermore, due to the pressure falls, ageostrophic component of the flow in the lower levels will likely contribute to the moderate values of SREH, with the highest values close to the warm front (reaching 300 J/kg in the 3 km layer). Initiation of the storms should not be problematic with the presence of strong frontal system and the position in the exit region of the jet-streak. Convection will be likely influenced by an overnight MCS, which might become part of the warm front precipitation shield of the developing low.In such configuration, well organised convection is predicted, very probably involving strong, rapidly progressing MCS in form of a bow-echo. Isolated supercells are not ruled out either, especially closer to the warm front, but due to the weaker shear values in the deep layer of troposphere, their persistence is questionable. Severe (and possibly even isolated extremely severe) wind gusts are expected to accompany the passage of such MCS. With MCS and/or supercells, tornadoes can occur as well, given strong low level shear and small dewpoint depressions, with F2 intensity not ruled out. Marginally large hail might be observed with stronger, more isolated cells and an excessive rainfall could be observed at the northwestern part of the system.Level 2 is issued for the region with the highest threat of severe (extremely severe) wind gusts and tornadoes. MCS might continue also overnight and progress towards Northern Finland, Kola penninsula and possibly also Karelian Republic, but with dimnishing boundary-layer instability, coverage and intensity of wind gusts will become less pronounced. For these regions, Level 1 seems to suffice at the moment.