INVEST 91L…REACTIVATION…FORECAST SYNOPSIS…AUG. 01, 2013…ISSUED 7:00 P.M. EDT…PHFC

Good evening everyone!

This will be a fairly brief update.

INVEST 91L has been re-activated, regarding the shower and thunderstorm activity I’ve been watching near and now over the Bahamas since the deactivation of 91L.  The current NHC Tropical Weather Outlook as of 2:00 p.m. EDT indicates a LOW (20%) probability of the wave becoming a tropical cyclone during the next 48 hours.

NHC GRAPHICAL TROPICAL WEATHER OUTLOOK (linked)

Based on satellite and surface information, there are currently no indications of a closed circulation.

INVEST 91L / CARIBBEAN SATELLITE LOOP IMAGERY

Analysis of the current wind shear product from CIMSS indicates shear values have remained only around 5-10 knots over the INVEST, and have continued to slowly decrease.  Convective activity that has been occurring is being enhanced by a diffluent flow aloft…however upper divergence is weak at best, and lower convergence is lacking at the moment.

CIMSS WIND SHEAR MAP

Based on the most recent run of the GFS wind shear and zonal shear forecast maps, shear is forecast to remain weak to non existent for the most part over the next 36 hours.  This COULD allow for some further slow organization before it becomes part of a frontal boundary, should the INVEST cease to ingest drier air.  Satellite loop imagery indicates drier air continues to be a problem, based on collapsing thunderstorm activity, and the presence of arc clouds (outflow boundaries) quickly moving away from the system.

GFS WIND SHEAR / ZONAL SHEAR FORECAST MAPS

The current steering flow at both 700-850 mb, and 500-850 mb indicates INVEST 91L will move toward the NW over the next 24-30 hours, with a turn toward the north, then another turn to the NNE or NE by 36-48 hours, based on the current run of the forecast steering layers maps from the PSU e-WALL site.  This INVEST is forecast to pas close enough, to bring showers and gusty winds to the South Florida coastal waters during Fri/Sat.

CURRENT STEERING

700-850 MB

500-850 MB

I will continue to monitor this INVEST as it becomes part of the frontal boundary, to see if baroclinic forcing has any affect on it.

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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7 Responses to INVEST 91L…REACTIVATION…FORECAST SYNOPSIS…AUG. 01, 2013…ISSUED 7:00 P.M. EDT…PHFC

  1. originallt says:

    At this late hour, ex-Dorian/ 91L has a nice “flair-up” going on. Will be interesting to see it on Friday morning when the sun comes up. I know Storm’s on to this.

  2. Elliot Lisak says:

    Good Evening Chief,

    I follow Monty’s thinking …. “one tough cookie”. Based on the season so far “things” seem to be fighting the odds. Can one make an assumption that the balance of storms this season are going to be “fighters”. It seems that the mechanics and components seem to be put together than previous systems?

    Thank you for your guidance.

    e

  3. Monty says:

    Thanks Storm. Dorian is one tough cookie!!

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