Science Tropical Weather

Atlantic Hurricane Season 2012

The 2012 Atlantic Hurricane Season officially began June 1st. We have already have had two named storms before the start of the season began which is historic itself.It was over 100 years when two named storms started before the hurricane season started.
All indicators are pointing to a less active season due to El Nino/Southern Oscillation (ENSO) conditions which are forecast to be Neutral and then later during the latter half of the season there is a 50% chance of El Nino conditions. For further reading of the indicators for the ENSO, click here

For the moment, the tropics in the Atlantic hurricane basin, which includes the Caribbean and Gulf of Mexico are relatively quiet.
The GFS 06Z model run (06/11) again has begun to indicate a system that will develop into the Gulf of Mexico and possibly strengthen in to a category 1 hurricane with landfall near Texas/Louisiana in about a week or so. The 12Z found no development and 18Z run found just minor development but no closed low, but I won’t rule out possible tropical development in that area, at least for the moment.

GFS 06Z Model

GFS 12Z Model

GFS 18Z Model

GFS Ensemble 500MB Mean Anamoly

The Madden Julian Oscillation (MJO) will be heading into octants 8 and 1 which normally indicates an upward motion and pressures in that area are forecasted to be lower some time near the middle of the month. With the MJO moving into the Western Caribbean/Gulf of Mexico along with the pressures dropping, storm development may occur. With respect of model uncertainty, as the MJO moving rapidly through octants 6 and 7 and will be eventually getting to octant 8. There is a possibility that the reason the models (especially the GFS) are having a hard time pinpointing the forecast of development in the Western Caribbean may be due to the rapid movement of the MJO through the octants.




While the tropics are quiet, it’s time to remember who the hurricane specialists are at the the NHC and what their duties are.

These people are the very best in their field. Not anyone can work as a specialist at the NHC. Only the best of the best were chosen. Although there will be those people who criticize every aspect of what the NHC does, thankfully those people are in the minority. These specialists do more than just view different satellite views and use some of the fantastic software they have (NAWIPS, ATCF, etc.) before they they write up the advisories, forecasts, warnings and other public products – there is a lot more behind the scenes. One thing the general public may not understand is that the specialist when writing up any of these advisory products, there are specific guidelines in how the report is written although there a few qualifiers that do allow some “freehand text” in a few of the reports. The forecaster will check on the latest model runs as this allows the specialist to help forecast where the storm might be heading. The data from the recon aircraft comes from the folks in the CARCAH (Chief Aerial Reconnaissance Coordination, All Hurricanes) office. The forecaster will have many conversations with whoever is staffing that office during the course of a recon mission – as that person is their link to the aircraft crew. The forecaster will also be checking with the TAFB (Tropical Analysis and Forecast Branch) as they provide a storm intensity estimate. The Hurricane Specialist uses the TAFB estimate as guidance but the Specialist will consider all available data in determining the intensity for the advisories.

A normal 6 hour forecast cycle;
The cycle begins, and 45 minutes later there is the reception of the fix data although that is the deadline time. The vast majority are in specialists hands 15 to 30 minutes after synoptic time. Aircraft fixes usually come right at synoptic time or even a bit earlier. An hour after the cycle started – the models are initialized. Again, that is the deadline time, usually the initialization of the models start a bit earlier. A few minutes later, the forecaster receives model guidance and starts the preparation for writing up the forecast. The primary text products in the forecast are the tropical advisory, forecast/advisory, and discussion. The second hour after the cycle started, the hotline call to both the (NWS) National Weather Service and the (DOD) Department of Defense is made. On the third hour, the forecaster has a deadline to release the tropical advisory products. Hours four and five are for possible media interviews. On hour six, the next cycle begins.

When storm watches or warnings are activated or during a landfall event the media is in the NHC building, but usually it’s the Director (Rick Knabb), Deputy Director (Ed Rappaport, PhD), or the Branch Chief (James Franklin) doing those interviews, not the Specialist on duty. There are a few times after the the advisory has been posted someone from the media may call and the forecaster on duty may answer any questions they may might have. When landfall is imminent within a stretch of shoreline, Federal and state level Emergency Managers, the NHC has someone who acts as a liaison between the EM’s and the NHC. Local EM’s are supposed to be in touch with their local WFO (Weather Forecast Office), who in turn relay their concerns to the NHC.

When hurricane season ends (officially) November 30th, the hurricane specialists remain busy outside the hurricane season. Occasionally, storms form before the official beginning of the hurricane season and also after the official end of the season, so specialists still have the responsibility with that storm too. They also have to attend some national and international hurricane conferences. The specialists do help the CPC (Climate Prediction Center), basically to prepare for the annual seasonal hurricane forecast. The specialists must also write seasonal summary articles and also participate in some applied research projects.

So each hurricane season these specialists (and who get little recognition) are the ones that have to deal with criticism when their forecast might be off, but more times than not, they are very close in their forecast. With budget cuts and the economy the way it is, these specialists can only work with the tools they have available to them. Maybe it’s time for people to really thank the specialists for all the hard work they do.


In this photo from left to right: Jack Beven, John Cangialosi, Eric Blake, Todd Kimberlain, Richard Pasch, Robbie Berg, Lixion Avila, James Franklin, Michael Brennan, Daniel Brown, Stacy Stewart

Not shown: US Navy Hurricane Specialist – LCDR Dave Roberts

Photo credit – Dennis Feltgen