TROPICAL DISTURBANCE INVEST 99L SYNOPSIS…AUGUST 01, 2012…ISSUED 9:45 A.M. EDT…PHFC

5:42 P.M. EDT AUG 01, 2012: I will have an update on Tropical Depression 5 soon.

TROPICAL STORM FORMATION: HIGH (60%)

CURRENT STORM TOTAL FOR THE 2012 HURRICANE SEASON:

NAMED STORMS: 4
HURRICANES: 1
INTENSE HURRICANES: 0
U.S. LAND FALLING STORMS: 2

para los productos de CNH en español por favor visite el sitio web del Centro Nacional de Huracanes

Good day everyone…first, I will be out of the office tomorrow…travelling to JAX

The NHC in Miami has just upgraded the probability of INVEST 99L becoming a tropical cyclone during the next 48 hours.

NHC TROPICAL WEATHER OUTLOOK

GLOBAL TRACKS INVEST 99L TRACKING MAP

Satellite imagery indicates Tropical Disturbance INVEST 99L has become better organized.  Prior to this, it had encountered some wind shear which had disrupted the structure somewhat, as the upper level anticyclone was displaced somewhat west of the COC, along with some westerly winds on the very northern extent, courtesy of a large upper level cutoff low/trof. The most recent real time wind shear product from CIMSS indicates shear values have dropped dramatically in the past 6 hours over the system.

INVEST 99L SATELLITE FLOATER IMAGERY

CIMSS WIND SHEAR PRODUCT

Based on the current improving structure, warm sst’s and conducive upper level winds, should this organization trend continue, I would not rule out a Tropical Depression later tonight, or tomorrow morning.

Based on the current update on the GFS Wind Shear Forecast map (06Z), albeit I will prefer to see the 12Z run, upper level winds are forecast to remain marginal to conducive during the next 72-84 hours.  Once this enters the E. Caribbean, the forecast calls for it to run into some shear, and some weakening may occur, which was depicted on the 06Z GFS run (opening it into a wave), then strengthening it once it approaches the W. Caribbean.  Given climatology, IRT the E. Caribbean, this appears to be a plausible solution to me at the moment.  However, we have all seen in the past, conditions can change rather abruptly in the tropics, and all of this could very well change.

GFS WIND SHEAR FORECAST

Based on satellite imagery, you’ll note the outflow channel/jet to the north of the system, which extends SEWD into the Atlantic to very close to the next wave.  The system is also beginning to display some light banding features, however is lacking any solid CDO development at the moment.

Based on various satellite imagery channels, a massive ridge is building over the U.S., and the trof that had extended into FL. is beginning to lift out.  This analysis, combined with the recent steering layers forecast maps indicates to me a continued west to WNW motion.

In summary, I am calling for this motion to continue for the next 60-72 hours, with a possible more WNW track as this nears or enters the Caribbean Sea.  Right now, I prefer pretty much the middle of the Model Guidance Package, with a blend of the TVCN/HWFI

06Z MODEL GUIDANCE

If conditions pan out as forecast, I do believe we will see a Tropical Depression late today, or early tomorrow, and quite possibly Tropical Storm Ernesto down the road.

Let’s be hopeful conditions do not become very favorable in the W. Caribbean should this survive the long trek, given the high TCHP values.

TCHP

I will be monitoring this situation on and off throughout the day, and will post any changes.

All interests in the Windward Islands should monitor the progress of this developing system.

Looking east, I am interested in the Tropical Wave, not coming off Africa, but behind it, given the large cyclonic turning.  This will be monitored once it enters the EATL.

EUMETSAT

Looking at MJO forecast indications, I suspect activity to increase around the 8th-10th of this month.

Have a blessed day!

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