Valid: Fri 28 Sep 2018 21:00 to Sat 29 Sep 2018 09:00 UTC
Issued: Fri 28 Sep 2018 21:09
This is a Mesoscale Discussion issued for a cyclone that is primarily driven by convection, issued twice daily before 9 and 21 UTC until the cyclone dissipates or becomes extratropical. This Mesocale Discussion is not an official product and does not substitute any warnings from National Meteorological Services. We welcome any feedback at firstname.lastname@example.org.
named Xenophon by the Greek National Weather Service (NOA)
At 28 SEP 1800UTC the storm centre was located near 35.3N and 19.3E
Estimated minimum pressure: 994 mb.
Maximum sustained winds: 30 m/s (60 kt, 110 km/h).
Maximum gusts: 40 m/s (70 kt, 125 km/h).
Until 1500 UTC the cyclone has moved very little and convection -although becoming more organized in bands- overall diminished, leading to little if any intensification of the vortex. After 1500 UTC, the cyclone has started to move east-northeastward. Simultaneously an area of intense convection has developed near the centre which has since become obscured, indicating that intensification of the inner circulation is likely occurring. The Hebert-Poteat technique estimate yielded a T number of 3.5 at 18 UTC. The Dvorak method also yields 3.5 for the Central Dense Overcast plus banding feature that has developed since, supporting a minimum pressure of 994 mb and maximum sustained winds near 28 m/s.
Numerical guidance has been a little slow in getting the cyclone to accelerate towards the east-northeast. The track forecast is based on a blend of the UKMO, ICON, GFS and ECMWF models. The cyclone core will likely make landfall around local noon Saturday across the southern Peloponnese. Interaction with the various mountain ranges is likely to cause a disruption of the inner vortex and a substantial weakening of the system as it reemerges over the Aegean Sea.
Some models, like ICON and GFS advertise a more southerly course, while UKMO and ECMWF favour a more northely one. In the ICON and GFS scenario, the vortex could be relatively intact and after 48 hours take a more southerly and slower course toward Turkey.
The recent devlopment of deep convection near the core suggests intensification is ongoing, which is estimated to continue until shortly before landfall. It is thought that the cyclone will briefly produce hurricane-force sustained winds in its southwestern quadrant. The strongest winds with gusts up to 40 m/s are likely to affect only the far southern Peloponnese and Kithira island, but gale and storm force winds will affect a much larger region. As a result storm surge of up to 1 metre seems likely to occur in some locations.
The main hazard of the cyclone will be the precipitation. Severe flash floods with possible landslides are possible, particular in Southeastern Peloponnese, Attica, Euboia, Eastern Thessaly where 100-250 mm are expected. these amounts are forecast for other regions:
Central and Eastern Makedonia: 80–160 mm
Western and Central Peloponnese, Central Greece, Southern and Western Crete,
Turkish west coast: 30-100 mm
Cyclades: 30-60 mm
Finally, there is a risk of tornadoes in the northeast quadrant of the cyclone, where long curved low-level hodographs are present, primarily affecting southern Peloponnese and Attica. For more details, refer to the convective forecast.
FH DATE & TIME LOCATION PRESSURE WIND MAX.GUSTS
00 28SEP 1800 UTC 35.3N 19.3E 994 mb 30 m/s 40 m/s
12 29SEP 0600 UTC 36.5N 21.4E 987 mb 35 m/s 40 m/s
... APPROACHING LAND
24 29SEP 1800 UTC 37.7N 23.7E 997 mb 25 m/s 30 m/s
... OVER SEA AGAIN
36 30SEP 0600 UTC 38.5N 25.0E 997 mb 25 m/s 30 m/s
48 30SEP 1800 UTC 39.7N 25.6E 999 mb 25 m/s 30 m/s
60 01OCT 0600 UTC 41.0N 26.0E 1003 mb 20 m/s 25 m/s
72 01OCT 1800 UTC