TROPICAL DISTURBANCE INVEST 96L FORECAST SYNOPSIS…ISSUED AUG. 16, 2015…4:50 P.M. EDT

SEVERE WEATHER THREAT: SLIGHT
TROPICAL STORM FORMATION:  MEDIUM (60%)

ALL forecasts contained on this site,  are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.

*NOTE: In the TROPICAL STORM FORMATION line above, probabilities are for during the next 5 day period.  My personal probability will be listed as either NONE, MONITORING or PROBABLE.  This does not necessarily mean something will develop, but that certain forecast conditions are likely to be present, favoring development.  Once NHC products become available, then the appropriate probability and percentage will be used.

Please refer to the link for the Storm Prediction Center in the box at the top of the page, just below the Hurricane Hunter graphics.

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Current Storm Total for 2015:

TOTAL STORMS: 3
HURRICANES: 0
INTENSE HURRICANES: 0
U.S. LANDFALLS: 2

StormW Seasonal Forecast:

TOTAL STORMS:             8
HURRICANES:                   3
INTENSE HURRICANES: 1

Good day everyone!

Enter into the eastern Atlantic MDR, Tropical Disturbance INVEST 96L which was designated in FTP data, early yesterday.  As of the 18Z (2:00 P.M. EDT) ATCF FTP data, the following information was available on INVEST 96L:

Location: 10.0°N 28.2°W
Moving: W at 15 mph
Min pressure: 1011 mb/29.85 in
Max sustained: 25 mph

Satellite loop imagery indicates the structure of 96L has improved over the past few hours, with an expansion in the cloud, and moisture field (based on water vapor loop imagery).  Consolidation appears to be mainly around the mid levels, based on AMSU surface wind data, and RGB satellite loop imagery.  Based on the 18Z AMSU data, there is currently no closed low level circulation.  Excellent rotation is noted in the satellite loop images however.

INVEST 96L FLOATER SATELLITE LOOP IMAGERY
avn0-lalo96L

rgb0-lalo96L

RAMSDIS/CIRA METEOSAT 4 FLOATER LOOP IMAGERY
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tropical_met_4km_ir4_floater

AMSU SURFACE WIND DATA 18Z
2015AL96_MPSATWD_2015081618_AMSU

2015AL96_MPSATWD_2015081618_SWHR

The recent wind shear map from CIMSS, did indicate an upper level anti-cyclone established above he system, just east of the approximate center.  The current streamline flow is providing somewhat of a divergent pattern, hence the apparent expansion of the cloud field.

INVEST 96L WIND SHEAR
tccaptureshear

The current SST and TPW maps indicate SST’s of 27-28C lie ahead of the system, with decent TPW surrounding the disturbance.  Upon analysis of water vapor loop images, a small amount of dry air is noted toward the west of the INVEST, however both loop images tend to indicate an expansion of the moisture field around the disturbance.  IF this trend can continue, dry air may only become  slight inhibiting factor in possible development.

INVEST 96L SST AND TPW
tccapturesst

tccapturetpw

WATER VAPOR LOOP IMAGES
wv0-lalo96L

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The most recent wind shear forecast from the GFS indicates, based on projection from the current forward speed, that the disturbance could remain in an environment where upper level winds may remain (albeit not optimal) more conducive than what we have seen, with the upper level anticyclone just lagging slightly behind the system.  This would tend to still provide some upper level outflow to the system.  The GFS zonal shear map does indicate zonal shear should remain below non conducive levels during the next 3-5 days.

Based on the premise that these indications are accurate, I have to agree at this time with the NHC probability of cyclone development of MEDIUM (60%) during the next 5 days.

NHC 5 DAY GRAPHICAL TROPICAL WEATHER OUTLOOK
two_atl_5d0

IF favorable conditions prevail, and a low level circulation becomes established, I cannot rule out a tropical depression within the next 72 hours.

Preliminary intensity guidance indicates the more accurate models bring this to hurricane strength in about 72 hours.  At this time, I feel this is a bit overdone, seeings there is a lack of a well defined surface circulation.

18Z INVEST 96L PRELIMINARY INTENSITY GUIDANCE
96L 18Z INTENSITY GUIDANCE

INVEST 96L is currently moving toward the west at around 15 mph, and based on forecast steering maps, this motion should continue during the next 72 hours.  At the moment, the GFS forecast steering map indicates pretty much a due west course over the next 5 days…however there is an indicated weakness in the subtropical ridge in about 96-120 hours out, from 00Z this evening.  This could have a tendency to impart more of a WNW track motion, which coincides with the NHC Graphical Tropical Weather Outlook.  However, this weakness is located fairly far west, near 30N;70W.  IF 96L is weak enough, the slim possibility could exist for the system to miss the weakness.  So, based on forecast steering, and analysis of the global models, I concur with the limited 18Z Dynamic Model guidance track of the GFNI.  This will of course change, if and when a low level circulation becomes established for the modeling to pick up on.

18Z DYNAMIC MODEL TRACK GUIDANCE
96L 18Z DYNAMIC GUIDANCE
I will continue to monitor this INVEST, and will try to have an update sometime tomorrow.

ALL global models are indicating an increase in activity in the EATL next week, with another low developing near the Cape Verde islands.  This remains to be seen.

Elsewhere, Tropical Storm formation is not expected during the next 7 days.

Have a blessed evening!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST MEMBER WEST CENTRAL FLORIDA AMS
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 TROPICAL DISTURBANCE INVEST 96L FORECAST SYNOPSIS…ISSUED AUG. 16, 2015…4:50 P.M. EDT

  1. dellamom says:

    Thank you, Storm, for your understandable and informative report. I see this morning that the probability is raised to high but they are still showing a slight northward curve toward the 5-day end time. I also note that there’s a lot of moisture in the environment around the Caribbean, the Gulf and the U.S. East Coast. Would that not make it easier for anything that breaks through the dry air to ramp up. especially since the waters are warm and have not had cooler waters churned up by preceding systems? I apologize for the simplistic questions.

  2. greg goodman says:

    Mr storm great update.Mr storm has the switch been turn on what do you think?

  3. Elliot Lisak says:

    Great Synopsis!

    Looks like things are going to get interesting. Andrew anniversary is coming up.

    Thank you!

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