Splitting Hairs, Changing Names, and Something New

Barbara at 2100Z on 5/31/13 (2:00 PDT on 5/30/13)

Sometimes storms bend the rules. Hurricane Barbara is one such storm. This tropical cyclone formed in the NE Pacific and managed to intensify to hurricane strength by the time it made landfall in southern Mexico the next day. After landfall it began to rapidly weaken and turned northward. The portion of Mexico it tracked across happens to be one of narrowest parts of Central America, so the possibility of it making its way to the Gulf of Mexico before completely dissipating was intriguingly high. Since records began, only a few storms have crossed between the NE Pacific and the Atlantic basin and the majority of those crossed into the NE Pacific, unlike Barbara. This storm was able to hold itself together even as it crossed the high terrain, but ended up losing its structure just before reaching the Gulf. Therefore, Hurricane Barbara did not cross from one basin to the other, or did it?

 

The last advisory issued by NHC for Barbara

 

 NOAA's satellite division, NESDIS, seems to believe the storm did enter the Atlantic basin and even released some of the storm's last data products under the "North Atlantic Ocean Basin" category. This confusion is likely due to a difference in basin definition between the National Hurricane Center (NHC) and NESDIS, with NHC defining the basin when the storm reaches the ocean and NESDIS defining the basin with a predetermined border that likely runs down Central America somewhere. Further complicating the matter is that the storm's remnants did make it to the Gulf. This means the exact criteria for a system to be a "tropical cyclone" must be used. Therefore, doubt could be raised that the storm still had all the required characteristics at the exact time it entered the Gulf of Mexico, but had lost them by the time the next round of advisories was issued.



NESDIS labeled Barbara (here called 02E) an Atlantic storm

With all the conflicting details concerning Barbara's track, the final decision must come from the agency most qualified to answer. In this case the NHC has the final say since it is the World Meteorological Organization's appointed Regional Meteorological Specialty Center (RMSC) for both the North Atlantic and the NE Pacific basins. Luckily, on the storm's last forecast discussion, the verdict is made very clear:

ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM

REMNANTS OF BARBARA DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022013
200 PM PDT THU MAY 30 2013

THREE SURFACE OBSERVING SITES NEAR COATZACOALCOS MEXICO HAVE BEEN PERSISTENTLY REPORTING WINDS FROM THE SOUTH TO SOUTHWEST...YET HIGH-RESOLUTION VISIBLE SATELLITE IMAGES HAVE BEEN SUGGESTING A WEAK CIRCULATION CENTERED TO THE EAST OF THESE SITES. APPARENTLY THE LATTER CIRCULATION IS EITHER NOT AT THE SURFACE OR IS EXTREMELY WEAK AND ILL DEFINED. SINCE BARBARA DOES NOT HAVE A WELL-DEFINED CENTER OF SURFACE CIRCULATION AND LACKS SUFFICIENT ORGANIZED DEEP
CONVECTION...IT NO LONGER QUALIFIES AS A TROPICAL CYCLONE... AND ADVISORIES ARE BEING DISCONTINUED. OUR OPERATIONAL ASSESSMENT IS THAT BARBARA DID NOT MAKE IT INTO THE GULF OF MEXICO AS A TROPICAL CYCLONE.
ALTHOUGH THE CYCLONE HAS DISSIPATED...DISTURBED WEATHER ASSOCIATED WITH THE REMNANTS OF BARBARA IS LIKELY TO PERSIST OVER SOUTHEASTERN MEXICO AND PORTIONS OF CENTRAL AMERICA FOR THE NEXT SEVERAL DAYS...AND A HEIGHTENED RISK OF DANGEROUS FLOODING AND MUD SLIDES WILL CONTINUE OVER THIS REGION.

FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 18.5N 94.5W 20 KT 25 MPH...REMNANTS
12H 31/0600Z...DISSIPATED

$
FORECASTER PASCH

NNNN

The final twist to this tale is that the remnants of Barbara have become the first Invest area in the Atlantic, within a few hours of the official start of the basin's season. If this area, 90L, does develop into a tropical cyclone, will that reopen the discussion about Barbara? The absolute final answer might not come until season is reviewed next winter.

-------

 



In other news, I have added a new page to the blog titled "Current Conditions". On this page is a plethora of satellite images and loops from all across the world along with some analysis products. All of the data is designed to display the most recent information from the source websites. The products chosen are ones I find particularly helpful in analyzing tropical cyclones and identifying potential areas of development.