11 September 2013

Humberto becomes first hurricane of the season

Within hours of breaking the record for latest date of first hurricane formation, Humberto was upgraded to a hurricane at 5am EDT today based on its satellite presentation.  The record holder is still Gustav, which became a hurricane at 8am EDT on September 11, 2002.
 (Note that operationally, advisories come out at 5am, 11am, 5pm, 11pm EDT (09Z, 15Z, 21Z, 03Z), while in the "best track" database, values are recorded at 2am, 8am, 2pm, 8pm EDT (06Z, 12Z, 18Z, 00Z).

So, Gustav (2002) and Humberto (2013) will have to share Sep 11th, then Diana (1984) has Sep 10th, then Erin (2001) has Sep 9th.

This morning, Humberto remains a minimal hurricane and is located about 300 miles west of the Cape Verde islands.

The track forecast remains the same... head north for a couple days then make a sharp turn to the west when it encounters a strong subtropical ridge.  By that time, the wind shear is expected to be quite strong, so it's forecast to weaken back to a tropical storm.  The image below is zoomed out quite far to give you a perspective of where it is and where it's going.  The last "S" marker is the NHC forecast position on Monday.

The disturbance near the Yucatan peninsula has indeed continued to develop, and is now consolidating near the Mexico/Belize border.  The central pressure is down to 1009mb, and though it will likely lose some of its organization as it crosses the peninsula, it is expected to make a quick comeback once it hits the Bay of Campeche tomorrow morning.

Infrared satellite image of the disturbance heading into the Yucatan peninsula.  The bright colors indicate very cold, high cloud tops found over intense thunderstorms.  (CIRA/RAMMB)
Model track guidance is keeping the future storm further south, making the southern Texas option less likely.  As far as intensity goes, models top out at a strong tropical storm, so it's not a huge concern... just heavy rain for Mexico, but the same part of Mexico that already got hit by TS Barry, TS Fernand, and TD 8 this year.  More on this tomorrow once we see how it fares crossing land.  If it becomes a tropical storm, the next name is Ingrid.

As expected, Gabrielle is losing its punch as it heads into cooler waters and higher shear.  As of this morning, it's just a skeletal cyclone; all that remains of it is a low-level cloud swirl.  Maximum sustained winds are 50mph according to the 5am EDT advisory, and it is centered just a few miles west of Bermuda (the magenta mark in the image below).  It is still expected to reach Nova Scotia by Friday night, probably not as a tropical entity though.

Enhanced satellite image of Gabrielle passing by Bermuda on Wednesday morning.  Low clouds show up as yellow, while high clouds show up as white.  (NOAA)

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