THE DOME
A forecast signal, not a warning. A forecast temperature peak over Sep 20-21 on the southern islands — Stari Grad on Hvar 33.9 °C , Korcula 33.5 , Supetar 32.8 , Zadar and Sibenik 31.8 — alongside a strengthening coastal bura , with daily maxima of 22.1 m/s, about 80 km/h , at the Velebit crossing and 19.6 m/s, about 71 km/h , at the Gruz quay, and a coastal wet-storm window of 45 to 50 percent . There is no official orange over Croatia , so this is a forecast signal read as a watch, not a warning .
THE RECORD
8 turning points on record since Sep 8.
Sep 19 cresting → building
Sep 18 ↑ moved up the board
Sep 17 ▽ slipped down the board
Sep 15 easing → cresting
Sep 13 peak → easing
Sep 12 cresting → peak
Sep 11 peak → cresting
Sep 8 appeared, peak
WHO IT TOUCHES
Aviation a holiday Monday over the Tokyo airports, a hail day on the High Plains and a bura pulse on the Adriatic coast
Maritime island ferries under a transitioning typhoon, a coastal cyclone in southern Brazil, and a strengthening bura on the Dalmatian coast
CONNECTED
Warm and unstable at both ends of the Mediterranean — one official warning, one forecast signal.
SOURCES — EFFIS/JRC with Copernicus-cited press, Sep 8 2026 · Italy Protezione Civile via met-press relay, Sep 17 2026 (reported) · Meteoalarm warnings JSON feed, read Sep 15 2026 (Croatia clear at orange and above) · Tomorrow.io v4 REST CI pre-step, daily-weather-brief/_ci-footprint.json, generated 09:14 UTC Sep 20 2026, 38 of 38 monitored locations returning — INTERNAL situational context, not a customer or prospect claim: a south-Dalmatian temperature peak on Sep 20-21 with Stari Grad on Hvar at 33.9 °C daily maximum and 33.4 °C apparent on Sep 21, Korcula 33.5 and 32.2, Supetar on Brac 32.8 and 32.2, Zadar Airport 31.8 and 30.2, Sibenik 31.8 and 30.3 and Split Airport 30.8 and 30.1; a coastal bura wind pulse with daily maxima of 22.1 m/s, about 80 km/h, at the Sveti Rok tunnel on the Velebit crossing, 19.6 m/s about 71 km/h at the Port of Gruz, 15.0 m/s about 54 km/h at Dubrovnik Airport and 14.9 m/s about 54 km/h at the Port of Split and at Marjan; and a coastal wet-storm window of 45 to 50 percent. In the United States the same pre-step has the anonymised Airport X location in east-central Illinois at 33.3 °C with 35.1 °C apparent on Sep 20, and Lincoln Financial Field in Philadelphia at 27.6 °C with a 94 percent precipitation-probability maximum and 1.1 mm of rain on Sep 20, easing to about 18 °C by Sep 22. No monitored location sits inside an official red or orange warning zone today. · Tomorrow.io v4 REST forecast API, read 09:15 UTC Sep 15 2026 (internal situational context) · Tomorrow.io v4 REST forecast API, read 10:15 UTC Sep 18 2026 (internal situational context) · Tomorrow.io v4 REST forecast API, read 11:11 UTC Sep 17 2026 (internal situational context) · Tomorrow.io v4 REST forecast pre-step, 38 of 38 monitored locations read at 07:03 UTC Sep 19 2026 — internal situational context, not a customer or prospect claim: no monitored location falls inside an official red or orange warning zone today. On the south Dalmatian coast the heat peaks about Sep 20 — Korcula 33.9 °C, the Stari Grad ferry port on Hvar 32.9 °C with an apparent 34.1, the Neretva and its delta 31.0 to 31.5 °C about Sep 21 and the Split coast 30.3 °C — ahead of a wet window on Sep 20 and 21 whose precipitation probability has REBOUNDED to 96 percent at Supetar on Brac and on the D8 between Makarska and Dubrovnik, 73 percent at Stari Grad, 72 percent in the Neretva delta and 71 percent at Vukovar on the Danube, the Sava through Zagreb and the Zagreb hospital cluster, against 20 to 35 percent in the previous day's read; a coastal wind and bura pulse follows about Sep 21 at 11 m/s in the Sveti Rok tunnel, 7.9 at the Port of Gruz, 7.1 at Sibenik and 6.7 at the Port of Split and Zadar. In the United States the east-central Illinois airport point is the live heat edge today at 34.5 °C with an apparent 36.8, inside the heat-advisory footprint, while Lincoln Financial Field in Philadelphia peaked Sep 18 at 29.3 °C with an apparent 30.1 and cools through a modest wet window on Sep 20 at 65 percent and 8.5 mm. · Tomorrow.io v4 REST forecast, 38 of 38 monitored locations, 09:13 UTC Sep 12 2026 (internal context) · Tomorrow.io v4 REST forecast, 38 of 38 monitored locations, 09:15 UTC Sep 11 2026 (internal context) · Tomorrow.io v4 REST forecast, 38 of 38 monitored locations, 09:38 UTC Sep 13 2026 (internal context) · Tomorrow.io v4 forecast API, read 07:03 UTC Sep 8 2026, 38 locations
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