SPECIAL UPDATE: TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS / TROPICAL DEPRESSION ELEVEN / OFFSHORE DEVELOPMENT FORECAST…SEP 29, 2013…ISSUED 5:00 P.M. EDT..PHFC

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Good evening everyone!

Just a brief note on T.D. 11, and developing offshore system.  Tropical Depression eleven is out in the CATL.  A analysis of current forecast steering layers maps, and dynamic model guidance still indicate this depression will meander over the next day or two, and eventually curve out toward the NE into the open Atlantic.

TROPICAL DEPRESSION ELEVEN SATELLITE LOOP IMAGERY

The offshore  system is forecast by all the global models to develop offshore, SW of Bermuda, and begin moving northward, then NNE.  ALL the global model guidance keeps this offshore far enough, that effects from this, if any along the Eastern Seaboard, should be minimal.  I am still gong to watch this, until I see some solid development begin, for any possible changes in guidance.

EASTERN U.S. SATELLITE LOOP IMAGERY

The area of disturbed weather in the SW Caribbean has been designated Tropical Disturbance INVEST 97L.  The most recent location of the “center”, as reported by ATCF FTP information was Latitude 14.0N…Longitude 77.3W.  The full information is contained in the Global Tracks 7 tracking map. Past positions are in italic.

GLOBAL TRACKS 7 INVEST 97L TRACKING MAP
INVEST 97L

INVEST 97L FLOATER SATELLITE LOOP IMAGERY / WATL SATELLITE LOOP IMAGERY

The NHC has assigned a LOW (20%) probability of 97L becoming a tropical cyclone over the next 48 hours, and a MEDIUM (40%) chance over the next 5 days.  Based on the ATCF information, and current steering layer mean map, the disturbance is moving very slowly to the NW,  toward a weakness over the western tip of Cuba, and extending into the central GOMEX.

NHC GRAPHICAL TROPICAL WEATHER OUTLOOK

Analysis of forecast steering layers charts valid for 00Z, indicate a NW should continue for the next 36 hours, before a turn toward the WNW.  Based on this analysis, I concur with the 18Z Dynamic Model guidance track FM9I for the time being.  This will most likely change, as a LLC is not well defined, and there could be a reformation.

18Z DYNAMIC MODEL GUIDANCE
18zatcfearlybestinvest97L

Currently, INVEST 97L is under about 20 knots of wind shear from the WSW, as an upper level anticyclone is becoming established just to the south of the center.  The current wind shear forecast map from the GFS indicates upper level wind should become more conducive during the next 24 hours, as the upper level anticyclone builds over 97L.  The 24 hour shear tendency does show wind shear has been on the decrease over 97L.  IF and WHEN this occurs, upper level winds are forecast to remain conducive (albeit, not optimal per current forecast)  for slow development.  Analysis of global model output indicates models are not too excited about this system at the moment, but may be do to the fact that the area has a broad circulation, and initialization may be somewhat difficult.  Given the various differences in the global models, I will be relying on real time obs for forecasting purposes, until we see how this plays out over the next 48-72 hours.  Forecast steering does indicate somewhat weak steering currents during the next 48-60 hours, so this system may have a chance to take some advantage of the improving upper level conditions.

CURRENT WIND SHEAR

SHEAR TENDENCY

GFS WIND SHEAR FORECAST

I will continue to monitor this system for signs of further development.

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS 
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)
CoCoRaHS OBSERVER

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About palmharborforecastcenter

I am a Tropical Forecast meteorologist, providing hurricane forecasts during the Atlantic Hurricane Season. I retired from the U.S. Coast Guard in July of 2001. Meteorology became my passion in high school, and I have continued my educational background in meteorology since 1996, when I undertook the study of Tropical Meteorology. While working toward my degree, I had to unexpectedly withdraw from college due to my oldest sons medical reasons. I do however, meet the educational criteria of the AMS to be recognized as a meteorologist. Studies include, but are not limited to the Navy Aerographers Mate course, Naval METOC meteorology course, Meteorology 2010 Sophomore level course while attending St. Petersburg College, Clearwater, FL., Basic Forecasting course for operational meteorologists from Rapid WX, meteorology institute, a four month meteorological internship, and extensive research on numerous meteorological topics such as the MJO, NAO, satellite imagery interpretation, etc. I have been forecasting Tropical Weather (Tropical Storms and Hurricanes) since 1996, with my main client being three different Coast Guard Commands.
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6 Responses to SPECIAL UPDATE: TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS / TROPICAL DEPRESSION ELEVEN / OFFSHORE DEVELOPMENT FORECAST…SEP 29, 2013…ISSUED 5:00 P.M. EDT..PHFC

  1. greg goodman says:

    Thanks mr storm for the update.Mr storm don’t we have a cold front coming down by the week end could that weaken it?

  2. originallt says:

    Thanks Storm. That coastal low, as you point out ,looks like it will do nothing but stir-up the seas a bit for us up here.

  3. TexasHurricane says:

    Probably AL to FL. It won’t come here…This is TX and they don’t like us. lol…..

  4. Monty says:

    Thanks Storm…looks like 97L could pose a threat to SE Texas??

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