TROPICAL CYCLONE FORMATION: MONITORING EATL
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(T. F. “Storm” Walsh III)
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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:
TOTAL STORMS: 5
INTENSE HURRICANES: 0
StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 13-15
INTENSE HURRICANES: 3-4
Good evening everyone!
The area of disturbed weather that has been hanging around the GOMEX since “M” (just kidding), has finally decided to break up. The extremely slow movement of this disturbance has caused some major, life threatening flooding over the past week along the Gulf Coast region. Based on the WPC QPF for the next 7 days, portions of Texas, especially the eastern 1/3, could receive 3-5 inches of additional rainfall. My thoughts, prayers and condolences are extended to those affected, and especially for those who have to deal with a loss of life.
The following are current storm precipitation totals estimated by NWS Doppler Radar out of Houston TX and Lake Charles LA.
Please make use to the following NWS Warning and advisory display, which is interactive. Just click on your area, or area of interest for the latest real time NWS advisories and statements.
An area of disturbed weather is located over the Yucatan Peninsula, and is moving toward the NW (see GOMEX satellite loop above). As this enters the GOMEX, I am not expecting development. The convection you note, being enhanced, is attributed to a diffluent flow in the wind shear pattern, creating weak to moderate divergence aloft. Based on the current and forecast wind shear products, upper level winds are currently unfavorable for development of this area, and NW shear is forecast during the next 72 hours.
A weak Tropical Wave is located east of the Windward Islands, moving toward the west at 20 knots. Based on the current and forecast wind shear products, I am not looking for development of this wave, as there is currently a zonal shear area over the Caribbean Sea, which is forecast to remain in place during the next 5 days. The GFS wind shear forecast does indicate for this shear to remain past 7 days, and possibly out to 10 days, however I will be analyzing this again, as 7-10 days out in the shear forecast, accuracy becomes questionable.
A Tropical Wave has entered the eastern Atlantic and is located near 20W, with the axis from 8.0N-19.0N. The wave is currently moving west at 15 kts. Based on analysis of the global models, indications are this wave begins to move NW in about 24-36 hours, and then re-curves around 5-6 days in the forecast period. Both the ECMWF and GFS are in agreement with this scenario. Now, I could be wrong on this, but I have one problem with that track scenario…the current steering layer product indicates the sub-tropical ridge to be oriented, in that a westerly steering flow is currently in place. The forecast of the 12Z run of the NCEP EMC Cyclogenesis Tracking Page indicates the NW motion in between 36-48 hours. At the moment, this does not concur with the current 12Z updated forecast steering maps, valid for 00Z this evening. Forecast steering shows at least for the next 72 hours, a more westerly motion to be in order. I will be looking at this over the next 3 days, for any changes to steering and/or global model forecast motion.
Currently, upper level winds are not fully conducive, but marginal at best for further organization, albeit the new update in the current shear product tends to indicate a limited, upper level anticyclonic pattern has become established. The current shear forecast indicates the current easterly zonal shear may relax enough during the next 48 hours for this wave to show a little more organization. The wave is embedded in an area of high TPW at the moment, and water vapor loop imagery indicates decent moisture surrounding it, however there appears to be some dust to the NNW of the wave, that may try to intrude.
The NOAA TCFP modeling, and the ECMWF ENSEMBLE members currently indicate a high probability of this wave becoming a depression within the next 24-48 hours, and I am calling for some slow organization of this wave during that time frame in the forecast period.
NOAA TCFP PROBABILITY
ECMWF ENSEMBLE PROBABILITY
The global models do for the most part, kill this feature in a few days. However, the models have taken an interest in the area of cloudiness behind this wave, and want to develop it in about 7-8 days. I cannot rule this out, as even though the current NASA dust forecast shows dust still entering the Atlantic, the NASA modeling also forecasts more surges of moisture coming off the African continent, as seen in the TPW forecast.
0.50 inches or less = very low moisture content
0.50 to 1.25 inches = low moisture content
1.25 to 1.75 inches = moderate moisture content
1.75 to 2.00 inches = high moisture content
2.00 inches or above = very high moisture content
The forecast for the subtropical ridge, is for it to still weaken, considerably during the next 24-48 hours, before strengthening again by day 10. As a note, I must say in my years of forecasting, I do not believe I have seen the A/B high remain on average, as strong as it has been this month, nor have I seen the SAL outbreaks be as numerous.
At any rate, IF the GFS 200 mb Velocity Potential anomalies forecast is correct, we may see a more favorable pattern regarding the Velocity Potential in about the next 5-6 days. This combined with the sub-tropical ridge forecast to weaken, may provide an increase in activity near Africa. Given this, should it come to fruition, combined the the ridge forecast to weaken, we should be able to see an increase in vertical instability over the Atlantic, which has been well below climatology, but has shown a sharp improvement over the past 24-36 hours.
I’ll reiterate again, I (we) are not expecting an active Cape Verde season or looking for significant development as far as the EATL/CATL based on the problems that have been plaguing the region. As discussed earlier in the season, myself, and the majority of meteorologist I follow, still believe we will see most of the activity confined to near the Bahamas, W. Caribbean sea, and GOMEX, which may become more prevalent from Sep. through Oct. Regarding waves traversing the MDR from now and during Sept….keep Earl in mind, as this may be the type of development situations we may encounter.
Elsewhere, Tropical Storm formation is not expected during the next 5-7 days
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS