INVEST 91L…EATL TROPICAL WAVE FORECAST SYNOPSIS…FRIDAY, AUG. 02, 2013…ISSUED 10:00 A.M. EDT…PHFC

Good day everyone!

Satellite loop imagery this morning indicates convection continues to expand in coverage with INVEST 91L.  The most recent loops of the RGB and Visible channels indicates a LLC may be trying to develop NW of the heavy convection, near Latitude 27.7N…Longitude 79.6W.

INVEST 91L SATELLITE FLOATER LOOP IMAGES

MELBOURNE NWS DOPPLER RADAR LOOP

The NHC has just recently lowered the probability of INVEST 91L becoming a tropical cyclone during the next 48 hours to 30%, which is down from 40% overnight.

NHC GRAPHICAL TROPICAL WEATHER OUTLOOK

It does appear that 91L may be trying to make a run for some development today, as pressures from around the area indicate a continued lowering trend has been taking place over the past 36-48 hours.

NDBC DATA
plot_wind_pres

plot_wind_pres (1)

Current wind shear values still show little to non existent shear at the moment, with an increasing value just east of the convection.  However, based on forecast motion, and the current run of the GFS wind shear and zonal shear maps indicate INVEST 91L may have a short window of favorable upper level winds over the next 18-24 hours, before becoming picked up by a frontal trof sometime this weekend.

Water vapor imagery indicates a slight presence of drier air, however much less pronounced this morning in the immediate area of the convection.

GOMEX WATER VAPOR LOOP

Based on this analysis, I believe 91L may be able to become a little better organized throughout today, however the window may be too short to see a tropical depression out of this.

Based on the current steering layers product from CIMSS, and the current run of the forecast steering layers maps from the PSU e-WALL site, 91L should continue on a NW track, to NNW track today, with more of a turn toward the N, then NE during the next 36-48 hours.  Based on this, I concur with the 12Z Dynamic Model Guidance suite, and in line with the TVCN / TVCC consensus.

12Z DYNAMIC MODEL GUIDANCE
12zatcfearlyinvest1best.DORIAN

I will continue to monitor INVEST 91L and will try to have another update late this afternoon, or early evening.

Elsewhere, an EATL tropical wave is located just off the African coast, with an initialized 1009 mb low embedded within the ITCZ.  Convection this morning seemed fairly consolidated, however strong easterly shear at the moment precludes any immediate development.  Based on the NHC Surface Analysis Map, the forecast is for this to move WSW over the next 24 hours, and based on forecast steering, may assume a westerly track shortly after.

EATL AND EUMETSAT IMAGERY

Analysis of the current SAL products, and water vapor imagery at both mid and upper levels, indicate this low is just at the edge of the SAL envelope, and could possibly have enough surrounding moisture to survive.

SAL PRODUCTS

I will continue to monitor this as the current wind shear forecast indicates upper level winds may become more conducive for development in about 72 hours from the 06Z initialization.

Tropical Storm formation is not expected through the next 48 hours.

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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8 Responses to INVEST 91L…EATL TROPICAL WAVE FORECAST SYNOPSIS…FRIDAY, AUG. 02, 2013…ISSUED 10:00 A.M. EDT…PHFC

  1. originallt says:

    Wow Storm, just checked in on your blog, and on the vis. satellite you provide, there is some pretty good rotation off the lower East Coast of FLA. 91L/Dorian, just won’t die!

  2. TexasHurricane says:

    I think you said before that the GOM may be in the run this year. Is this still your thoughts? Think TX might be in that if so.

    • Right now, as far as just a guess at the moment…yes on both. I just can’t see shear lasting ALL season in the Caribbean. In fact, the GOMEX so far has been pretty favorable as far as shear and instability goes

      • TexasHurricane says:

        Hmmmm, ok. I am so used to the majority of people usually saying east coast,that it is kinda surprising to here there may be a good possibility. But since this is coming from you that the GOM and TX may be a possible threat I will definitely be keeping an eye out. Thanks Storm

  3. Elliot Lisak says:

    Good Morning Chief,

    Your right on point and target. If one was to work on the “upswing beginning the last 10 days” … that would indicate we would see a depression/tropical every week. That means that were going to be busy until Thanksgving at least this is what I read after reading the new CSU report this morning (http://tropical.atmos.colostate.edu/forecasts/2013/aug2013/aug2013.pdf).

    Your thoughts … Master Chief please

    • Most of the activity will most likely occur from the 3rd week of Aug, through Sept. Oct could see 2-3, possibly 4, depending on where formation takes place…we could see a goo deal of mid latitude systems, given the warmer sst anomalies in the mid latitudes.

  4. originallt says:

    Thanks Storm. I see that Colorado State University has just issued a statement calling for lower than average possibility for tropical development through August 15th. Of course you told us this days ago!

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