Wel in het Engels, sorry dus voor de mensen die daar wat minder bedreven in zijn. Vragen staat vrij.
I've been following the possibility of TSMS on Friday and Saturday for a couple of days now, and several things have become clear:
- the strength of the ULL, and consequently the surface low, near Ireland is not clear yet: numerical models are still shifting things around too much to tell what will become the final situation
- LL moisture seems to be low and thin with an even more dry layer on top vertically extending from 850 to 650 hPa
- especially the GFS model is over-estimating surface moisture (Td's up to 23 dgrs.) and thus predicting unrealistic values of 2000 J/Kg of CAPE.
- location of the frontal system is still very much unsure, the GFS is still swapping the CF west and east every run and also the ECMWF and UKMO models still seem too uncertain
- regional aka meso-scale models don't seem to be useful ATM since the global models aren't even sure about some of the key large-scale features (ULL magnitude, jet location)
ATM though I tend to be very careful with predicting severe TSMS because of all the uncertainty. One of the things that does seem quite clear is that temperatures are going up to 28-32 degrees in northern France and the Benelux countries on Friday and perhaps on Saturday as well. I do believe there will be some CAPE available for storms, perhaps a few hundred or even up to 1000 J/Kg, but nothing near the values the GFS is predicting. Forced lifting due to the frontal system moving in seems to be limited ATM, though orographic lifting could trigger/enhance a few TSMS here and there. To make a long story short: I think things will be quite marginal on Friday and Saturday,mostly associated with a weak front moving trough on Saturday. This front is likely to give mostly clouds and light rain. Perhaps a few isolated or embedded TSMS but nothing severe. If any TSTM does become severe, largest threat is likely to be hail and wind gusts.
I've been following the possibility of TSMS on Friday and Saturday for a couple of days now, and several things have become clear:
- the strength of the ULL, and consequently the surface low, near Ireland is not clear yet: numerical models are still shifting things around too much to tell what will become the final situation
- LL moisture seems to be low and thin with an even more dry layer on top vertically extending from 850 to 650 hPa
- especially the GFS model is over-estimating surface moisture (Td's up to 23 dgrs.) and thus predicting unrealistic values of 2000 J/Kg of CAPE.
- location of the frontal system is still very much unsure, the GFS is still swapping the CF west and east every run and also the ECMWF and UKMO models still seem too uncertain
- regional aka meso-scale models don't seem to be useful ATM since the global models aren't even sure about some of the key large-scale features (ULL magnitude, jet location)
ATM though I tend to be very careful with predicting severe TSMS because of all the uncertainty. One of the things that does seem quite clear is that temperatures are going up to 28-32 degrees in northern France and the Benelux countries on Friday and perhaps on Saturday as well. I do believe there will be some CAPE available for storms, perhaps a few hundred or even up to 1000 J/Kg, but nothing near the values the GFS is predicting. Forced lifting due to the frontal system moving in seems to be limited ATM, though orographic lifting could trigger/enhance a few TSMS here and there. To make a long story short: I think things will be quite marginal on Friday and Saturday,mostly associated with a weak front moving trough on Saturday. This front is likely to give mostly clouds and light rain. Perhaps a few isolated or embedded TSMS but nothing severe. If any TSTM does become severe, largest threat is likely to be hail and wind gusts.
