TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS…SEP. 02, 2013…ISSUED 11:55 A.M. EDT…PHFC

Good day everyone!

Satellite loop imagery of this morning indicates the convection associated with INVEST 97L pretty much got obliterated by dry air overnight.  Dry air can be noted as the dark, and the orange tinted areas in water vapor imagery.  Given that the LLC is located in a general broad area of circulation, and dry air intrusion, the NHC has lowered the probability of INVEST 97L developing into a tropical cyclone to LOW (20%) during the next 48 hours, and to MEDIUM (50%) over the next 5 days.

NHC GRAPHICAL TROPICAL WEATHER OUTLOOK

GLOBAL TRACKS 97L TRACKING MAP
INVEST 97L

Various satellite loop imagery channels indicate a pretty compact LLC, especially on the IR2 (Shortwave) image.  The system has been moving toward the west, however the last few frames of satellite loop imagery indicates it may have become quasi-stationary.  This would be in response to a trof north of the system, and an approaching trof from the U.S. east coast.

INVEST 97L FLOATER SATELLITE LOOP IMAGERY

SHORTWAVE LOOP

CARIBBEAN SATELLITE LOOP IMAGERY


CARIBBEAN WATER VAPOR LOOP IMAGERY

The recent CIMSS shear map indicates an upper level anticyclone over 97L, and based on the recent GFS wind shear forecast, this is projected to move westward into the central Caribbean, then centered just south of Hispaniola.

CIMSS WIND SHEAR

GFS WIND SHEAR FORECAST

Based on this, the dry air may hold it back for the time being, however with the disturbance moistening the air with each burst of convection, and as it moves into higher TCHP, it could diminish the surrounding dry air.  Given these factors, there could be some slow organization as it enters the eastern Caribbean, however a negating factor in the eastern Caribbean is usually fairly brisk surface winds, which will have the tendency to create diverging air at the surface, not allowing for air to converge at the center of the system.

Given these factors, further development may not occur until 97L enters the central Caribbean.  Here is where we may have 2 possible scenarios.  Based on the current steering layer mean, a weakness in the ridge is detected pretty much over Florida right now.  However, the associated trof may not be strong enough to provide that much northern component right now.  Although, it is a weakness, and the slowing of forward speed may be due to the influence of this weakness.  Based on analysis of current forecast steering layers maps, there is a disagreement, in that one model indicates a weaker system, moving further west past Hispaniola, and the other, taking INVEST 97L WNW very soon.  Given the current uncertainty of which steering pattern is going to prevail, I have to concur with the 12Z run of the Dynamic Model Guidance track toward the WNW, however I am to the left of the TVCC / TVCN, and to the right of the NGX2.

12Z DYNAMIC MODEL GUIDANCE
12zatcfearlyinvest2best97L

Depending on which direction 97L heads, should it come out of the Caribbean, it would almost be certain to encounter westerly shear.  IF it remains more of a west tracker and remains in the Caribbean, strengthening is likely to occur.  This is based off the last update of the GFS wind shear forecast.

Again, wind shear can change quickly, and steering currents can change within 24 hours.  If the trend continues in model guidance to a WNW track, residents along the eastern Seaboard from Florida to the OBX may wish to monitor this system closely for any significant changes.

Elsewhere, I will be monitoring a tropical wave that has moved doff the African coast for any signs of development over the next few days.

EUMETSAT LOOP IMAGERY

I intend to have another update on INVEST 97L sometime this evening.

Have a blessed day!

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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5 Responses to TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS…SEP. 02, 2013…ISSUED 11:55 A.M. EDT…PHFC

  1. originallt says:

    Looks like 98L has just been declared, just off the African coast, my UN-Official (Storm is OFFICIAL!) take on this is that this could be the one to watch, it looks well structured all ready, is fairly low in latitude, and has a long trip over Atlantic waters giving it time to grow. I know Storm will look at this later today or tomorrow.

  2. Monty says:

    Thanks Storm for taking the time to give us this update. It looks like if your track forecast is right…97L could flirt with TPA?? Echoing LT…enjoy your day…well deserved!!

  3. TexasHurricane says:

    Thanks Storm! September 2 and no storm at all. wow…

  4. originallt says:

    Thanks Storm for this Labor Day up-date. Hope you enjoy the day.

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