Storm Forecast
Valid: Tue 29 Oct 2024 06:00 to Wed 30 Oct 2024 06:00 UTC
Issued: Mon 28 Oct 2024 22:35
Forecaster: PUCIK

A level 2 was issued across E Spain mainly for heavy rainfall, large to very large hail and tornadoes.

A level 1 was issued across S - Central Spain mainly for heavy rainfall, large hail and tornadoes.

DISCUSSION

... Spain ...

A deep low at mid to upper troposphere is forecast to move from N Africa to SE Spain. This will result in a passage of a pronounced exit region of a cyclonically curved jet in the afternoon to early night hours across E Spain. Models show continuous warm air advection regime across the area from the Balearic Sea almost during the whole forecast period. Combined with an onshore/upslope easterly flow towards the higher terrain, many hours of storm activity are likely, starting in the night from Monday to Tuesday and persisting till Wednesday. Storms will be fed by a pool of high CAPE over the Balearic Sea, where an elevated mixed layer has been advected from Sahara. CAPE will be the highest at the E coastline of Spain, decreasing inland.

Widespread storms are forecast to initiate in the highlighted area. Storm coverage may vary a bit during the day. The first maximum may be in the morning hours, followed by some decrease in the activity as the dry air in the mid-troposphere envelops the area. In the evening, approach of the jet exit and associated lift will moisten the profiles again, resulting in another uptick of storm activity. Combination of high coverage with strongly sheared environment (0-6 km bulk shear exceeding 25 m/s and curved hodographs yielding high SRH), will result in well-organised linear segments as a main convective mode. Segments will be oriented mostly parallel to the mean flow as cold pools will be rather weak. This orientation is also shown by several high resolution models.

In this setting, heavy rain will be easily the main threat with some areas likely receiving more than 200 mm of rainfall. Besides rain, other severe weather hazards will be possible as well. ARCHaMo shows high probability of even 5+ cm hail because of strongly sheared environment and high values of CAPE above -10 deg C isotherm. The highest risk of very large hail will be along the coastlines and in case that supercells manage to form before the storms grow quickly upscale. The same pertains to tornadoes as well. Here, another potential limitiation is that the storms may quickly turn from surface based into elevated as they move inland. Nevertheless, forecast hodographs reveal high values of streamwise vorticity in the inflow tot he storms in the bottom 500 m and a risk of tornadoes will be present wherever a surface-based storm can form. Risk of severe wind gusts will be mostly mitigated by the lack of cold pool production in storms.