Za nama je najtoplije jutro dosadašnjeg tijeka godine. Velik dio Dalmacije imao je tropsku noć, što znači da se minimalna jutarnja temperatura nije spuštala ispod 25,0°C.
Pri tome je Dubrovnik bio najtopliji s 28,8°C. Slijedi Komiža s 28,1°C, Split 27,8°C, Palagruža 28,6°C, Makarska 26,9°C, Hvar 26,9°C, Šibenik 26,6°C itd.
Međutim, događaj koji je obilježio prošlu noć je prolazak olujnog sustava preko područja susjedne BiH. Njegov prolazak izazvao je sredinom noći jaku buru u Dalmaciji s olujnim udarima. Bura je donijela dosad najjači fenski učinak na našim područjima. O tome svjedoče izmjereni podaci s meteoroloških postaja.
Tako su tri različite meteorološke postaje oko 1:30 zabilježile skok temperature zraka na nevjerojatnih 36°C. To je ujedno bila viša vrijednost temperature zraka od izmjerenog dnevnog maksimuma u utorak. Ovako visoke vrijednosti noćnih temperatura, osobito iza ponoći, još nikada nisu zabilježene u Dalmaciji u povijesti službenih meteoroloških mjerenja. U to vrijeme gotovo je cijela obala imala temperatura zraka iznad 30°C.
Kako nastaje fenska bura?
[Žuto]Za razumjeti mehanizam nastanka fenskog vjetra potrebno je objasniti osnovne zakone fizike na primjeru vertikalnog kretanja vjetra. Zrak koji se uzdiže hladi se za 1°C svakih 100 m. Zbog hlađenja zraka na određenoj nadmorskoj visini dolazi do kondenzacije vodene pare (nastanak oblaka i oborine).
Tim procesom oslobađa se latentna toplina, pa se daljnjim uzdizanjem zrak hladi po znatno sporijoj stopi od 0,6°C svakih 100 m. Obrnut je proces kada se zrak spušta. Zamislimo čest zraka koja se spušta niz padinu. Tlak zraka (pritisak) viši je u podnožju planine nego na njenom vrhu. Spuštajuća se čest zraka tako kreće iz područja nižeg u područje višeg tlaka, te se zbog toga sabija.
To rezultira povišenjem njene temperature i njenim isušivanjem. Ukratko, svaki vjetar koji se spušta niz planinu zagrijava se i isušuje.[KRAJ]
Do kraja dana veliko nevrijeme u unutrašnjosti
Vruć i vrlo vruć dan očekuje nas i danas. U popodnevnim i večernjim satima velik dio unutrašnjosti zemlje zahvatit će olujno nevrijeme. Nažalost, prognostički modeli ukazuju na mogućnost jake tuče. Nevrijeme neće zahvatiti Dalmaciju.
ESTOFEX UPOZORENJE
[Sivo]Storm Forecast
Valid: Wed 19 Jul 2023 06:00 to Thu 20 Jul 2023 06:00 UTC
Issued: Tue 18 Jul 2023 22:28
Forecaster: GROENEMEIJER
A level 3 was issued across parts of Italy, Austria, Slovenia, Hungary, Croatia, Bosnia and Serbia, firstly for very large hail and damaging winds, and secondly for very heavy precipitation.
SYNOPSIS
A strong zonal jet streak is located across central Europe at the northern fringe of a pronounced elevated mixed layer. The combination of the associated steep lapse rates and ample low-level humidity across Po Valley and the northwestern Balkans lead to very high MLCAPE in a zone from Serbia through the northwestern Balkans, with values of 2000-3000 J/kg, into the Po Valley, where values in the 3000-5000 J/kg range are predicted. A high-end severe weather situation with very large hail and widespread severe winds is expected to develop as a subtle upper-level vorticity maximum moves into the region, setting the stage for convective initiation of this volatile environment.
DISCUSSION
Alpine region, Pannonian Plain, and the northwestern, western and central Balkans...
NWP models suggest that on Wednesday morning scattered rapidly-moving elevated storms may be ongoing across the large level 2 area. Forecasting their locations and intensity is very difficult even 6 to 8 hours ahead. Although these storms pose some risk of severe winds and large hail, their elevated nature limits this risk, and stronger storms are expected to develop later in the day.
During the afternoon, as the aforementioned vorticity maximum approaches the Alps from the west, per all NWP guidance, widespread initiation is expected across the southern and central Alps. The storms will do so in a very unstable and strongly sheared environment, so that rapid evolution into supercells, followed by a transition to one or more bow echoes is expected. Additional storms could form across the Dinaric Alps, and possibly across the Po Valley as parcels are lifted ahead of outflow boundaries from the Alps.
The very high instability and strong storm-relative low-level wind in this environment suggest that some storms will likely produce very large hail in the 5-10 cm range. The transition in a bow echo is expected during the evening as the storms move across the northwestern Balkans, and possibly Hungary. Widespread severe winds are expected as a result, including some extremely severe winds of more than 32 m/s. Overnight, the system should very gradually diminish in intensity as an environment with lower CAPE is encountered across southern Serbia, Romania, and Bulgaria.[KRAJ]
