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Good day everyone!
Just a little more activity in the tropics this morning. The main area to be noted is in the CATL. The NHC still has the Graphical Tropical Weather outlook centered on the wave located near 42W. WHY?…I have no idea. The area from that location, eastward IS a broad area of low pressure, however as seen in CATL Water Vapor loop imagery, the area more favorable as far as less dry air, is the low to the east, near 33W. This area has been sustaining convection now for the past 24 hours, and the area of moisture has spread out slightly more during the over night hours. The NHC still designates a MEDIUM (30%) probability of tropical cyclone development over the next 5 days with the broad low near 42W.
Based on analysis of satellite loop images, lower convergence, and upper divergence maps this morning, I still believe the area to watch is the low located east of this area, near 33W.
The wind shear product from CIMSS at 0900Z indicated a diffluent pattern on the wind shear map over the low at 33W.
Analysis of the Zonal Wind Shear forecast from the GFS indicates upper level winds may become more conducive for development in about 48 – 72 hours as this wave continues toward the west over the next 3 – 4 days. I do believe IF this can sustain convection, and initiate a better LLC during the next 24 hours, this could be designated INVEST 96L.
Based on my analysis of the current run of the forecast steering layers maps from the PSU e-WALL site, this low should continue westward, and based on my track thinking, I do believe some further, slow organization is probable, given the increase in moisture, and the current shear forecast.
Satellite imagery also indicates another area coming off the African continent, and another located over the continent approaching 0W longitude. I will be monitoring these areas closely, as well as the area in the CATL, as we should begin to see an upswing in activity as an upward motion phase of the MJO enters the region. The current MJO Multivariate Index forecast from the GFS members, with the ECMWF following suite, except much weaker, indicates the MJO moving into Octant or Phase 1, and displaying a moderate to strong signal over the next 10 days. This means an increase in tropical moisture and lift in the atmosphere over the CATL/AFRICA region. This seems to be verifying at the moment, as if you go back to water vapor imagery, you will notice an increase in water vapor from 35W longitude, eastward.
Another item of note is…the NAO is forecast to remain strongly negative over the next 7 – 10 days. This implies a weakening of the Icelandic low, and the subtropical ridge. As you can see, being noted in my previous forecasts regarding this, trades are slower, which is now evident by these system moving slower to the west, and somewhat of a recovery in SST anomalies in the MDR. What all of this eludes to is, a build of of heat over the tropical Atlantic over the next few days.
I will continue to monitor the situation in the tropics, and since Global models have apparently not handled cyclogenesis very well, I am not going to mention what they indicate or don’t indicate, and all forecasts will be based on near real time information, and 4 -5 day forecast parameters of the various elements listed in this forecast.
I will have another update tomorrow.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
OFFICIAL SKYWARN SPOTTER (ADVANCED)