Disclaimer: This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service. ALL forecasts herein are the result of my analysis, and I am solely responsible for the content. As always, follow the NHC and Local NWS office guidelines, and your local Emergency Management officials for emergency decisions.
(T. F. “Storm” Walsh III)
For those who have donated to my site, your help has been greatly appreciated. For those not aware, donations to my site help me offset my out of pocket expenses…such as some of the model maps you view on here, which are only available due to my subscription to the corresponding sites. The F5 Data maps I post as well, is another out of pocket expense (monthly subscription). Updates to software (weather related), and costs for my domain name are also out of pocket to me. To donate, please click the DONATE button to the right. Any help you provide is immensely appreciated! Without your help, I may not be able to continue paying the monthly subscription charges for access to all of the best information I use in my forecasts.
Good evening everyone!
Analysis was somewhat aggravating this evening. The Global Models, with the exception of the ECMWF and UKMET, are still indicating development of a sub-tropical storm by around the 15th – 16th of the month. The GFS is still the most bullish, however on the 12Z run, it had whatever it is forecasting, down to max. T.S. strength, and on the recent 18Z run, has it back to approximately a strong CAT 2 hurricane.
Once again, I am going to mention, please do not try and play armchair meteorologist and state that it’s going to go here or there, and strike as a hurricane, or, this and that. It is best to have knowledge as to the way which models act which way at certain times, and have had experience forecasting with them for several years before making ANY type of decision on what may happen. Models are fed numerous parameters of the atmosphere and oceans, with each model having different grids and layers, and come up with mathematical solutions. These solutions are printed as the maps we see, and since each model is different in the depth of the layers/grids, etc., each will show a different solution. Again, these are tools that WE use as forecasters, along with analysis of multiple parameters, pattern recognition, climatology etc., along with remembering how the various models have acted or performed over the years. For instance, here is an explanation of the “FIM” model (click link)
This is for the GFS
The ECMWF is considered the premiere model, and is far more complicated.
Based on this evenings analysis, again, it’s going to depend on which model is correct as to whether or not we see any development. Since the ECMWF computes 91 -137 different levels of the atmosphere, and usually outperforms the other global models, I tend to side with it.
Satellite loop imagery indicates that the area in the W. Caribbean at the moment, is pretty much associated with a mid – upper level low, with thunderstorm activity being enhanced by a diffluent flow aloft. Surface obs. do not indicate any type of circulation at the surface right now, and the latest forecast indicates (valid for 00Z tonight) that winds closer to the surface are out of the east (seen circled in the 925 mb map), and a small mid level circulation (circled in the 500 mb map).
925 MB NCEP FORECAST
500 MB NCEP FORECAST
My analysis revealed that there are some favorable signals forecast to occur, which would tend to indicate some type of development IVO extreme W. Caribbean to extreme W. GOMEX. Some of these being as follows: The MJO (Madden Julian Oscillation) is forecast by both the ECMWF and GEFS ensemble members to enter into Octants 1 and 2 which has the tendency to promote development, due to upward motion in the atmosphere provided by this oscillation. The link will take you to an article on this phenomenon:
MJO PHASE SPACE DIAGRAM FORECAST
The following maps indicate as well, that the MJO is forecast to be over the GOMEX/Caribbean by next week, however more strongly pronounced by the 18th of the month.
MJO FILTERED VELOCITY POTENTIAL ANOMALIES MAPS (BLUES, PURPLES AND BLACKS INDICATE FAVORABLE AREAS OF UPWARD VERTICAL VELOCITY…RED CIRCLE)
The ECMWF and GFS indicate decent humidity levels up to 500 mb in the forecast period.
The big difference is, the GFS indicates upper level winds to turn favorable for development, developing an upper level anticyclone (circled), while the ECMWF indicates wind shear to remain over the GOMEX.
GFS WIND SHEAR FORECAST
Given the GFS usually nails the wind shear forecast, (albeit I’m a little skeptical given the performance in the GFS flip flopping back and forth in it’s current forecast of this supposed system, and making ALBERTO a hurricane in the first few days of development when it initialized), and since other global models are indicating development, at various intensities, I’m going to stick my neck out here, and surmise that we COULD possibly see a weak development in the W. GOMEX somewhere after the 15th of the month. I’m basing this on a “blend” of the models analyzed, especially the forecast 500 mb normalized anomaly pattern that incinerates the lowering of pressures at the 500 mb level during the time frame of the forecast period.
ECMWF NORMALIZED 500 MB ANOMALIES
NCEP ENSEMBLE MEAN ANOMALIES
PLEASE, do not ask the question “is it going to hit here?”, or “will it hit me?” , because as of right now, the models all indicate a different path. This question can be better answered “once” and “if” we get a closed surface circulation. However, based on what the models are showing as far as a wind field, if development does occur, it appears it will also be sub-tropical in nature, as the maximum sustained winds that are forecast, will be well east of any “center”. IF development occurs, I again look for whatever it may be, to become another east weighted system. Based on the unknown at this time, this forecast should be considered low confidence. In fact, this may have to be played by “real time”, in that there will be more certainty in the forecast once I see something “promising” in satellite imagery or in analysis of the wind flow from the surface to mid levels.
I will mostly be updating on my time off from work, as far as a regular tropical outlook. During an active system however, I will do my best to provide a forecast once I am home from work.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS