TROPICAL DISTURBANCE INVEST 97L FORECAST SYNOPSIS…ISSUED SEP. 25, 2016…4:30 P.M. EDT

TROPICAL CYCLONE FORMATION: INVEST 97L (90%)

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(T. F. “Storm” Walsh III)

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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:

TOTAL STORMS: 12
HURRICANES: 4
MAJOR HURRICANES: 1
U.S.LANDFALLS: 4

StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 13-15
HURRICANES: 6-7
INTENSE HURRICANES: 3-4

Good evening everyone!

Tropical Storm Karl has become post tropical, and the NHC in Miami issued the last advisory at 11:00 a.m., as it moves to the NE at near 50 mph.

New to the list is Tropical Disturbance INVEST 97L in the central Atlantic.  As of the 18Z ATCF BTK report, the following information was available on INVEST 97L:

2:00 PM EDT Sun Sep 25
Location: 7.7°N 39.4°W
Moving: W at 20 mph
Min pressure: 1012 mb / 29.88 in
Max sustained: 30 mph

I derived the forward motion and speed via LAT/LONG calculations from the period 06Z to 18Z.

The NHC has designated a HIGH (90%) probability of cyclone development during the next five days.

NHC 5 DAY GRAPHICAL TROPICAL WEATHER OUTLOOK
two_atl_5d0

Currently, the disturbance is in a somewhat marginal upper level environment, with the reported center just to the south of a small, and what appears to be a developing upper level anticyclone.  The recent upper level satellite derived winds from CIMSS indicates an upper level outflow may already becoming slowly established.

CIMSS WIND SHEAR PRODUCT
wg8shr

Based on the current wind shear forecast / 200 mb pattern forecast, upper level winds should become more conducive within the next 48 hours, with the premise of the upper level anticyclone becoming better established.  Once this system enters the Caribbean, the upper level pattern is forecast to become extremely favorable for development of this system, and while I do not like going past 72-96 hours in the forecast period regarding the shear forecast, the GFS shear forecast indicates these extremely favorable upper level winds to become established closer to the central Caribbean by days 5-6. The ECMWF has a little slower solution, but does indicate improving conditions by day 7 in the 200 mb streamline pattern.

GFS WIND SHEAR FORECAST
gfs_dl_shear_carib_13
gfs_dl_shear_carib_17

gfs_dl_shear_carib_25

Current satellite loop imagery indicates the system may be getting slowly better organized, as the circulation appears to have tightened up over the past few hours.  The item lacking right now is convection close to the center.  Convection at the moment is being displaced north of the center, due to the flow out of the south, from the system being south of the center of the upper level anticyclone.  Based on my analysis of the forecast pattern, should it be accurate, and forward motion of the system, I expect development to occur a little quicker once the system passes 50W.  It is possible this could become our next depression within the next 72 hours.

INVEST 97L SATELLITE LOOP IMAGERY
avn0-lalo-97l

rgb0-lalo-97l

CATL SATELLITE LOOP IMAGERY
avn-lcatl

As far as future intensity, it will depend on actual track, and if the forecast parameters come to fruition and hold true for the next 5-7 days.  Current intensity modeling brings this to category ONE hurricane strength by 72 hours, however given the large circulation, and forward speed, I believe this is overdone.  However, if the forecast favorable conditions occur, I would expect this to become a hurricane in the Caribbean Sea.  Forecast intensity in my opinion, is up in the air at the moment, as well as exact track, given the system is not developed yet.  However, we have some pretty favorable forecast conditions being shown at the moment….Favorable upper level winds forecast, very high TPW values forecast, warm SST’s of 30C, and very high OHC.  Based on the first four parameters, the disturbance, or most likely tropical storm at that time, will be crossing over high OHC values.  Given the values shown, combined with the other favorable forecast conditions, this system would have the potential for Rapid Intensification.  Put it all together, and this system COULD have the potential to become a MAJOR HURRICANE.

CURRENT OHC (OCEAN HEAT CONTENT)
tcheat_atl_2016
ohc_aqg3_latest_natl

TPW FORECAST
gfs_pwat_atlantic_21

INVEST 97L is currently heading to the west, and could fluctuate over the next few days between W to WNW.  I expect this motion to continue during the next 5 days, and the system should enter the Caribbean Sea within the next 96 hours.  Once in the Caribbean, it may begin to gain latitude, as a deep layer trof is forecast to be over, or just offshore of the Eastern Seaboard.  This would have a tendency to draw it north.  Right now, all of the global models tend to indicate this, bring it across Cuba by around day 8 in the forecast period.  However, this system is very far south right now, and future track will depend on the timing of the ridge/trof pattern.  Just 2 days ago, and prior, modeling was indicating the ridge to remain in place, sending the system into the GOMEX, and as of yesterday, a flip to generating a strong, deep layer trof off the U.S. east coast. Right now, track guidance should be considered preliminary, as models do differ somewhat in the timing of the arrival of the trof.  Also, should INVEST 97L remain weak, it would have the chance to travel a little bit further west in the Caribbean.  Right now, until we can see how developed it becomes near the Windward Islands, into the central Caribbean, there are just too many variables at the moment to provide a “spot on” forecast track.  Regardless, interests in the Windward Islands, the southeastern and south-central Caribbean Sea, as well as the northern coast of South America, should monitor the progress of this system.

GFS
gfs_mslp_uv10m_mex_40
CMC GGEM

cmc_precip_thick_mex_41

ECMWFecmwf-240-hour

ATCF 18Z DYNAMIC GUIDANCE
97l-18z-dynamic

Unfortunately, I will not be able to have an update tomorrow, as I have to fill in for a co-worker tomorrow.  However, I should have updates on both Tue. and Wed.  Should this by chance become a threat for the U.S., I will most likely do special updates at such a time, after I arrive home from work, should the need arise.

Elsewhere, Tropical Storm formation is not expected during the next 5-7 days.

Have a blessed day!

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 97L FORECAST SYNOPSIS…ISSUED SEP. 25, 2016…4:30 P.M. EDT

  1. E.M. Lisak says:

    Which is more stress. Trump vs. Clinton or a Major Hurricane. I think South Florida is due!
    Either way we can always count on Storm. The future will be ascertained, clearly and concised with out hype . This is what we need. Keep up the good work. Glad that you don’t work for the major TV stations.

  2. Diane says:

    Thank you. Always appreciate your analysis.

  3. Dellamom says:

    Thank you storm. I will be watching and reading your excellent reports.

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