Tropical Depression Nine formed on Tuesday night in the central Bay of Campeche and is drifting east toward Mexico’s Yucatan peninsula.  Although poorly organized, conditions are becoming somewhat more favorable for further development and it could potentially be upgraded to Tropical Storm Hanna later today, but time is running short.

Currently, the depression has maximum sustained winds of 35 mph, just 4 mph away from tropical storm status.  Tropical storm warnings have been hoisted from Celestun to Frontera in the Mexico state of Campeche along the west side of the Yucatan peninsula. Five to 10 inches of rain are possible from the storm – with isolated amounts to 15 inches, which may trigger life-threatening flash floods, the National Hurricane Center warns.


Visible satellite image from GOES-East at 9:15am EDT. The approximate center of TD9 is marked with a red L. (NASA)

An Air Force reconnaissance flight is underway into the depression, and so far it has not been able to locate any tropical storm force surface winds.  A radar from Sabancuy is picking up a primary curved rainband wrapping around the center of the low, which is located about 120 miles west of Campeche, Mexico.


Long radar loop of TD9 from Sabancuy through 10:45 a.m. ET (images from SMN, loop from UM/RSMAS)

As is typically the case with very weak and disorganized systems, the track forecast is a mess.  Models have little to grab on to, and interaction with land complicates matters further.  Even among skillful global and regional hurricane models, there is quite a bit of spread in forecasts out to two days, let alone four or five.  But in general, it should pass over the Yucatan peninsula on Thursday into Friday, then perhaps emerge intact over the western Caribbean on Friday afternoon.  Only then will we know if there’s a coherent system left to forecast.


Track forecasts from the 06Z runs of 4 global models, 5 regional models, and the National Hurricane Center (OFCL). (UAlbany)

At this late point in the hurricane season, it is rare to get a tropical cyclone to form in the Bay of Campeche, and unprecedented to get one moving east.  In fact, Tropical Depression 9 is the 4th latest genesis on record there, and it formed almost exactly where an 1859 storm formed on October 24.  That storm became a hurricane and hit the Tampa area… this one does not appear to have such a destiny.


Previous storms that formed in the Bay of Campeche on October 20 or later since 1851. (NOAA)

In an average season by this date (using 1981-2010 as the reference period), there would be 10 named storms, 5 hurricanes, and 2 major hurricanes.  2014 has produced 7 named storms, 6 hurricanes, and 2 major hurricanes.  But in terms of Accumulated Cyclone Energy, or ACE, 2014 is at 70 percent of an average season.  There are still five weeks remaining in the official Atlantic hurricane season.