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(T. F. “Storm” Walsh III)
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Based on analysis of satellite loop imagery, INVEST 91L remains very poorly organized, however looks a little better since this afternoon.
At 18Z this afternoon, based on the 18Z ATCF BTK product, the following information was available on INVEST 91L:
MOTION: WNW @ 15 mph
MAX. SUSTAINED WIND: 30 mph
EST. PRESSURE: 1012 mb / 29.88 in
The disturbance is moving WNW. Based on my analysis of the current and forecast steering layers maps, and current model track guidance, I am not expecting any major change in guidance. IF this holds, any “center” that may develop could come ashore from Brownsville TX, southward into MX., just south of Matamoros near Laguna Madre. Right now, this is the best educated guess, as the models do not have a well defined closed low pressure area to initialize. Based on the model guidance shown, I am in between the TCLP and TABS models in the graphic, and the ECMWF EPS guidance.
18Z MODEL GUIDANCE
ECMWF EPS GUIDANCE
Analysis this evening, indicates wind shear is currently over the system, on the order of between 30-40 knots.
CIMSS CURRENT WIND SHEAR MAP
GFS AND ECMWF WIND SHEAR FORECAST
Analysis of the wind shear forecast maps from the GFS and ECMWF (ABOVE), along with the SHIPS diagnostic report from 18Z, indicates upper level winds may remain non conducive for development during the next 4 days. Thereafter, wind shear values are forecast to be below 20 kts.
SHIPS DIAGNOSTIC REPORT
However, neither the GFS or ECMWF indicate a very favorable upper level outflow pattern. In fact, none of the Global Models analyzed indicates a closed low or sub-tropical depression. Since conditions can and sometimes do change abruptly, I will continue to monitor this area for any development, however in my professional opinion, I feel this has only a slim chance for development once it enters the GOMEX, and I concur with the NHC 5 day Tropical Weather Outlook of only a LOW (20%) probability of cyclone development over the next 5 days (which I feel is generous). Based on current upper level wind analysis, 91L is under the axis of an upper level trof. As long as it remains in the axis, development should not occur. I will be awful surprised if INVEST 91L survives crossing the Yucatan Peninsula. Regardless, this could bring some much needed rain to Texas.
WPC 7 DAY ACCUMULATED TOTAL PRECIPITATION 7 DAY FORECAST
ECMWF 7 AND 10 DAY TOTAL PRECIPITATION FORECAST
Elsewhere, analysis of the ECMWF indicated on the 00Z run from last night, that a small storm or depression would develop off the SE coast of FL. in a few days. The probability of a depression was at near 60%. Based on analysis this late afternoon, the ECMWF EPS probability guidance has lowered dramatically.
ECMWF EPS 00Z AND 12Z PROBABILITY FORECAST MAPS
However, what the ECMWF is picking up on (with the GFS now following suit), is that a trof split is forecast to occur, with a piece backing toward the SW, then toward the west. A strong ridge will be situated north of the area (circled in white), and the piece of the trof split (circled in red) will retrograde or is forecast to retrograde westward. Both ECMWF and GFS indicate lowering of 500 mb normalized pressure anomalies. Analysis of the models DOES NOT indicate anything at the surface, however with the MJO once again forecast to go into phases 1 and 2, conditions could become favorable for some type of surface development to begin, and I will be monitoring this area.
ECMWF 500 MB NORMALIZED ANOMALIES FORECAST
MJO PHASE DIAGRAM FORECAST
I will mostly be updating on my time off from work, as far as a regular tropical outlook. During an active system however, I will do my best to provide a forecast once I am home from work.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS