Volgens meneer Groenemijer, bijna een autoriteit op severe weather gebied, morgen leuke kansen voor severe weather, met kans op upgrade naar moderate risk ! Maar zoals ik ook al eerder zei : de grootste kansen in gebiet over de grens... Maar wie weet ben ik daar morgen wel...
grtn Arjen
SYNOPSIS
West of a ridge located from the British Isles to northern Italy at the beginning of the forecast period, a strong (120 kt @ 300 hPa) southwesterly mid/upper jet will move eastward into western europe. Downstream...over northern Poland, a vort. max. is moving eastsoutheastward into northern Belarus. A shortwave trough over northern Greece will move southward affecting the Aegean Sea area, reaching the eastern Mediterranean Sea near Cyprus at the end of the period.
DISCUSSION
......
Over northern France and Belgium, warm air advection should be able to initiate and sustain elevated convective activity in the early morning hours (ahead of the main forcing for upward vertical motion due to differential vorticity advection on approach of the mid/upper jet). This activity is expected to gradually move northeastward affecting The Benelux and parts of northwestern Germany. Potential for some severe weather will increase as the mid/upper jet moves into France and strong forcing will initiate more storms over northern, western and central parts of France in the afternoon hours while deep layer shear increases to around 70 knots. MLCAPE30 should be able to rise to values on the order of 500 J/kg ahead of the system over much of France, The BeNeNux and western germany and it may be somewhat higher over east-central France. Strong forcing and moderately strong (20 kt) low-level shear suggests that most storms will organise into linear convective systems producing strong wind gusts and posing a minor threat of large hail. Given that low LCL heights are expected to be quite low over northern France, the southeastern Benelux countries, Rheinland and Nordrhein-Westfalen, one or two weak tornadoes cannot be ruled out in those areas. mountains. since CAPE will be on the order of 1000 J/kg there (GFS seems to be too low with CAPE this time), large hail threat will be higher. Since the deep-layer shear will be very strong (~ 60-70kt) there is a high severe weather threat with any storm that forms in that area. Main threat will be damaging winds. A few tornadoes may occur as the activity reaches northern switzerland/upper rhine valley/baden-wurttemberg, where somewhat higher low-level moisture is forecast than further west, leading to somewhat lower LCL's. The setup is again on the slight risk/mdt risk boundary. Given that models have a low coverage of storms I tend to keep it slight there....but I might change my mind. Your thoughts?
grtn Arjen
SYNOPSIS
West of a ridge located from the British Isles to northern Italy at the beginning of the forecast period, a strong (120 kt @ 300 hPa) southwesterly mid/upper jet will move eastward into western europe. Downstream...over northern Poland, a vort. max. is moving eastsoutheastward into northern Belarus. A shortwave trough over northern Greece will move southward affecting the Aegean Sea area, reaching the eastern Mediterranean Sea near Cyprus at the end of the period.
DISCUSSION
......
Over northern France and Belgium, warm air advection should be able to initiate and sustain elevated convective activity in the early morning hours (ahead of the main forcing for upward vertical motion due to differential vorticity advection on approach of the mid/upper jet). This activity is expected to gradually move northeastward affecting The Benelux and parts of northwestern Germany. Potential for some severe weather will increase as the mid/upper jet moves into France and strong forcing will initiate more storms over northern, western and central parts of France in the afternoon hours while deep layer shear increases to around 70 knots. MLCAPE30 should be able to rise to values on the order of 500 J/kg ahead of the system over much of France, The BeNeNux and western germany and it may be somewhat higher over east-central France. Strong forcing and moderately strong (20 kt) low-level shear suggests that most storms will organise into linear convective systems producing strong wind gusts and posing a minor threat of large hail. Given that low LCL heights are expected to be quite low over northern France, the southeastern Benelux countries, Rheinland and Nordrhein-Westfalen, one or two weak tornadoes cannot be ruled out in those areas. mountains. since CAPE will be on the order of 1000 J/kg there (GFS seems to be too low with CAPE this time), large hail threat will be higher. Since the deep-layer shear will be very strong (~ 60-70kt) there is a high severe weather threat with any storm that forms in that area. Main threat will be damaging winds. A few tornadoes may occur as the activity reaches northern switzerland/upper rhine valley/baden-wurttemberg, where somewhat higher low-level moisture is forecast than further west, leading to somewhat lower LCL's. The setup is again on the slight risk/mdt risk boundary. Given that models have a low coverage of storms I tend to keep it slight there....but I might change my mind. Your thoughts?
*NM*