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!
Minimum temperatures should begin to modify by the beginning of the week, but slowly. However, by Jan. 14-15, another blast of Arctic air is forecast to spill back into the deep south. I will try to update on this next time I’m off from work.
I’ve been mulling over various information, and wanted to post another preliminary forecast regarding the 2018 hurricane season. Based on analysis of the most current updates in climate modeling, the “consensus” still appears to be ENSO neutral-cold bias conditions for the 2018 hurricane season. Some models warmer, others colder. The UKMET Nino Plume forecast is the only model indicating La Nina conditions.
NINO 3.4 PLUMES BOM
NINO 3.4 PLUMES JMA MODEL
UKMET NINO 3.4 PLUME FORECAST
Analysis of the forecast SST anomalies indicates the current La Nina to gradually weaken somewhat by June through Aug.
Based on the values and trend of the current Nino Plume forecasts, I performed another analysis of the ONI (Oceanic Nino Index). Given the discrepancies between climate models, and using an average of both temperature anomalies and trends, the following years came the closest as far as analog years. Of course, as we get closer to the start of the season, this information will change somewhat, and I should have a better choice for analogs. The years currently representative of the ONI trends/temps were 1985, 1996,2001, 2006, and 2012. These years averaged 13.6 total storms or rounded up, 14 total storms. Based on these analogs I took the average, and the year with the highest total(s), and came up with the following preliminary range.
TOTAL STORMS: 14-19
MAJOR HURRICANES: 3-5
Again, once we get to May, and even June of this year, I should be able to narrow the field. Various parameters will be re-analyzed during various times of the season, given that some uncertainties can occur such as rapid cooling or warming of the Nino 3.4 region, state of the AMO, and state of the Gulf of Guinea.
Points to ponder in the above SST anomaly forecasts that would tend to indicate an above average season:
ENSO Neutral cold bias or weak La Nina
Possible colder Gulf of Guinea anomalies
Continued warm AMO
Indian Ocean Dipole
ENSO and the AMO kind of work hand in hand (per se’). When the ENSO is in a neutral to cold state, and the AMO is warm and above average, this is seen in the atmosphere as an imbalance, or to put it another way, “Mother Nature” “SEES” more heat in the Atlantic (heat and moisture), thus in regards to air, there is more “net lift” on the Atlantic side, or rising air over the Atlantic, and sinking air over the Equatorial Pacific and nearby vicinity. The “majority” of the models indicate either ENOS Neutral with a cold bias, or weak La Nina conditions. It is noted in the SST anomaly forecasts, that above average SST anomalies range from 20N, northward.
As we all know, neutral to La Nina conditions allow for decreased wind shear, or little to none over the Atlantic MDR region. The following is the current forecast from the CFSv2 Climate model regarding the Atlantic u200-u850 wind velocities in m/s, or in simpler terms, the values of the difference in wind velocity from the 200 mb level, down to the 850 mb level, otherwise known as wind shear. The forecast indicates wind shear to be below normal or below average close to the entire 2018 hurricane season. The CFS has been consistent now for 2 months.
CFSv2 WIND SHEAR FORECAST
IRT the Gulf of Guinea: This generally plays a role in rainfall over Guinea, or in some cases, rainfall over the West African Sahel region. Let’s look at the 2016 and 2017 hurricane seasons. The Gulf of Guinea was pretty much showing warmer anomalies, albeit weaker warm anomalies in 2017. A warmer Gulf of Guinea, in general, keeps the ITCZ pretty much suppressed further south over the African continent. This causes the Sahel region to remain drier with average or below average rainfall. If you notice the SST anomaly forecasts, some of the climate modeling, especially the CFS are indicating a colder Gulf of Guinea. Given the pressure gradient created by cooling the Gulf of Guinea, in relation to the hotter African continent (higher pressure now over the Gulf of Guinea, lower pressures north), the ITCZ is pushed further north, and can reach into the Sahel region. This allows for more rainfall over the Sahel, which in turn helps to cut down on SAL outbreaks and their severity. This increases the chance of a greater number of tropical waves, and an increase in intensity of these waves. Hence, the possibility of an above average season.
GULF OF GUINEA
2012 GULF OF GUINEA COLD ANOMALY
2017 GULF OF GUINEA WARM ANOMALY
The IOD (Indian Ocean Dipole), (to my understanding from previous readings) has an effect on the WAM (West African Monsoon) circulation, in that a negative IOD has the tendency not to disrupt the WAM, which plays a part in rainfall, and anomalous westerly surface winds at near 10N latitude. We did observe the WAM a few times near the peak of the 2017 season, however if my understanding of this feature is correct, the WAM is more pronounced during a negative IOD. The 2017 season witnessed a “neutral to “positive IOD phase. The current forecast indicates the IOD may be neutral to warm, or neutral to positive. This could be a slightly negating factor for a busy season, however the other factors mentioned would be positive for an above average season.
Positive: cooler in the tropical eastern Indian Ocean and warmer in the tropical western Indian Ocean.
Negative: warmer in the tropical eastern Indian Ocean and cooler in the tropical western Indian Ocean.
Again, I will continue to monitor these factors for significant changes, which would change the outlook.
I also wanted to post some hurricane preparedness information early, so you will have plenty of time to go over the information for you to know what you need, and how to prepare if a storm affects your area. Click on each graphic to view the guide. These guides, and Pet Evacuation information are available on the right side of the page, under LINKS.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS