SEVERE WEATHER RISK: SLIGHT
TROPICAL STORM FORMATION: PROBABLE
ALL forecasts contained on this site, are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.
*NOTE: In the TROPICAL STORM FORMATION line above, probabilities are for during the next 5 day period. My personal probability will be listed as either NONE or PROBABLE. Once NHC products become available, then the appropriate probability and percentage will be used.
I will be focusing mainly on the tropics from here on out, as preforming analysis for both severe weather and the tropics is very time consuming, and I will be working with time constraints due in part to my prat time employment. Please refer to the link for the Storm Prediction Center in the box at the top of the page, just below the Hurricane Hunter graphics.
Good day everyone!
Tomorrow, or midnight tonight, will officially begin the 2015 Atlantic Hurricane Season. Thus far, we have already had one named system…ANA, which began as a sub-tropical low, and did transition to a bona fide tropical storm. In my tropical forecasts, following below the severe weather and tropical storm probs, I will list total storms, hurricanes, and U.S. landfalls. Thus far, we are at 1 named storm, 0 hurricanes, and 1 U.S. landfall.
Once again, based on my previous pre-season analysis…we know by now we are in a decent El Nino pattern, and the MDR in the Atlantic is much cooler based on current SST Anomalies. In short, given that El Nino increases wind shear over the Caribbean Sea and portions of the Atlantic MDR, and with SST Anomalies not really supporting Cape Verde development thus far, along with various other factors previously mentioned, I am looking for a below average season.
Based on my analysis of the most recent forecast update regarding the onset of an El Nino episode, I have come up with 5 analog years in reference to the ONI (Oceanic Nino Index) that closely resemble the “forecast trend” vice actual ONI Value, albeit a couple of the analog year values are close. These analog years are 1957, 1972, 1982, 1991, and 1997.
Based on the ONI analogs, we pretty much averaged a total of 8 Storms, 3 Hurricanes, and 1 Intense Hurricane. Based on data from 1968 – 2003 and 1981 – 2010 an average season has been said to have 11 – 12 Storms, 6 hurricanes, and 2 -3 Intense Hurricanes. The long term average of 100 years however was established at 10-6-2. After doing some averaging and dividing, I have come up with the following totals for the 2015 Hurricane Season:
TOTAL STORMS: 8 – 10
HURRICANES: 3 – 5
INTENSE HURRICANES: 1 – 2
Analysis this evening of global models one again indicates models picking up on a development ow low pressure, now forecast to initiate either in the Caribbean, south of western Cuba, to between the FL. Straits and Bahamas in about 96 – 120 hours. The only models at the moment not showing this are the ECMWF and the UKMET. The GFS, CMC, NAVGEM, FIM8, and FIM 9 models are all on board. Right now, the CMC appears to be the outlier in that it shows a 982 mb low, which equates to a high end tropical storm to Cat 1 Hurricane. A couple of items at the moment which lead me to believe it is the outlier, the current wind shear forecast is not optimal for this, and this forecast low will be associated and may even phase with a 500 mb trof or cutoff low.
Based on the recent Cyclone Phase Evolution diagrams, this could become subtropical should it develop, as the diagrams from both the GFS and CMC indicate this may attain a shallow warm core.
Based on analysis of the wind field of both FIM models, and the GFS at the moment, if development does in fact occur, we may only see a subtropical depression, to low end subtropical storm, with the strongest winds away from the center.
The wind shear forecast and upper level streamlines indicate the CMC with a more favorable upper level environment, but with both supporting a weaker storm solution. The streamlines indicate an upper level flow similar to what ANA encountered, but with stronger shear values.
GFS WIND SHEAR FORECAST
CMC WIND SHEAR FORECAST
The majority of the models keep this system offshore and eventually moving toward the NNE, with the CMC keeping it much closer to the coast. Right now, it appears this may be the correct solution, however until I can locate more forecast steering charts, I am at a hindrance with one chart from the PSU e-WALL site, with that being the GFS.
I have to work tomorrow, Wed. and Sat., so I will try to keep you updated in between, or when I am able to post.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST MEMBER WEST CENTRAL FLORIDA AMS