TROPICAL CYCLONE FORMATION: NONE
Disclaimer: This site is not affiliated with the National Hurricane Center, Storm Prediction Center, or National Weather Service. ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(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 personal out of pocket expenses…such as some of the model maps you view on here, are only available due to my subscription to the corresponding site. The F5 Data maps I post, also 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! Although it may seem I am not here and working in support of your donation, I have to work my forecasting time around my ever changing work schedule.
CURRENT 2016 TROPICAL CYCLONE TOTALS:
TOTAL STORMS: 4
INTENSE HURRICANES: 0
StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 14-16
INTENSE HURRICANES: 3-4
Good day everyone!
Still very quiet over the Atlantic basin today. Dry air pretty much dominates the basin with a combination of African dust, and subsidence from the large subtropical ridge. Dry air is noted as orange and black areas in the water vapor satellite imagery.
A high amplitude tropical wave which I had mentioned in my last synopsis, appears somewhat better defined in this afternoons satellite imagery, and is located from 17N – 7N latitude, and 37W longitude, with scattered convection from 3N-10N. Upper level winds are only marginal at the moment. This wave is under the influence of some dry air to its west. I am going to monitor this area as it moves into the Bahamas (based on forecast steering currents), as upper level winds may be a bit more conducive, and SST’s/TCHP could allow for the wave to moisten the atmosphere a bit more. However, by this time in the forecast period, if forecast steering is accurate, there should be a weakness in the ridge, just north of the Bahamas, which would allow this feature to re-curve toward the NNE.
Elsewhere, satellite imagery indicates the far eastern Atlantic is quiet at the moment, albeit another vigorous wave is noted over west Africa.
I know some of you may still be wondering WHY we don’t really see any “action” as of yet. Same old answer I’m afraid. The subtropical ridge is still fairly strong, with a pressure initialized this morning of 1031 mb (30.45 in). This is some fairly high pressure, and the ridge is aiding in drying out the atmosphere, along with what African dust has been blowing off the African continent. The following graphics show the CURRENT and 24 hour projection of the subtropical ridge, along with position and strength based on CLIMATOLOGY. You’ll note the ridge is approximately 5 mb stronger than climatology, which is pushing higher pressures further south toward the MDR region. I hate to say it again, but until the subtropical ridge can weaken, and/or become re-positioned, it’s going to keep drying the atmosphere in the mid levels, due to sinking air. Now, the GFS and ECMWF are still indicating a pattern shift of the ridge, based on MSLPA forecast maps. However, the ridge appears to keep “meandering” during the next 7-10 days, so we very well may see a fluctuation of where and when lowering surface pressures may occur over the next 7-10 days.
Although there is quite a bit of SAL over the MDR which came off Africa a few days ago, it is noted that the SAL (African dust) is not appearing as robust over the African Sahel region as it has been lately, which could indicate a pattern change may be about to occur. Convective activity over Africa is not really plentiful at the moment. Dust in the EUMETSAT image (dust channel) is noted as either pink or magenta areas.
EUMETSAT DUST CHANNEL
Analysis of the global models does not indicate development over the next 7 days. However, the GFS does want to develop a wave that exits the African continent at around days 8-10 in the forecast period. The CMC is kind of sniffing out a low (1010 mb) as well, but a little further north than the GFS, during the same period. The ECMWF is not indicating development at the moment, but does indicate a tongue of lowering pressure off the coast of Africa.
Upon analyzing the current and forecast CHI 200 mb anomaly charts, combined with what the global models mentioned are indicating, we may see an increase in convective activity as we may get a little help from the MJO briefly, and my thinking at the moment is not until the last week of this month, to the first week of Aug. The possibility still does exists in that we may not get a named system this month. This is not too uncommon, as climatology once again is the dictating factor here. I’ll post this excerpt from an article authored by Dr. Phil Klotzbach, explaining a portion of the workings of the MJO. The period mentioned regarding enhanced activity for the Atlantic, should be the period of the last week of this month to the beginning of Aug:
Because of this observed clustering, the MJO has been considered a likely modulator of TC activity. Maloney and Hartmann (2000) documented that Gulf of Mexico and western Caribbean tropical cyclogenesis was 4 times more likely to occur when lower-tropospheric MJO wind anomalies in the eastern Pacific were westerly than when they were easterly. Mo (2000) demonstrated that TC activity in the Atlantic was most enhanced when the convectively enhanced phase of the tropical intraseasonal oscillation, of which the MJO was the dominant signal, was located over eastern Africa and the Indian Ocean and suppressed convection was located over the tropical Pacific. Maloney and Shaman (2008) show that TC activity in the east Atlantic tends to be suppressed about 5–10 days before a maximum in regional precipitation over the east Atlantic and West Africa, while TC activity is enhanced about 5–10 days after the maximum in regional precipitation. Barrett and Leslie (2009), using the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center’s real-time MJO index, documented that storms were 4 times more likely to make landfall along the U.S. coastline when the MJO had a large amplitude and convection was enhanced at 120°W.
CFS 200 MB VERTICAL VELOCITY POTENTIAL FORECAST
One of the pluses we do have for development is that wind shear over the Tropical Atlantic has been running consistently below climatology. However, vertical instability is still well below climatology, which ties into the factors I mentioned above.
Tropical Cyclone Heat Potential (TCHP) or Ocean Heat Content (OHC) has shown a slight increase since the beginning of the month.
I will be monitoring things the next couple of days, and intend to update Tue. and Wed. I work Thu-Sat.
Tropical Storm formation is not expected during the next 7-10 days.
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS