INVEST 99L FORECAST SYNOPSIS…ISSUED OCT. 17, 2016…3:40 P.M. EDT

TROPICAL CYCLONE FORMATION: INVEST 99L: MEDIUM (60%)

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(T. F. “Storm” Walsh III)

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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:

TOTAL STORMS: 14
HURRICANES: 6
MAJOR HURRICANES: 3
U.S.LANDFALLS: 5

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

Good day everyone!

The area of cloudiness and showers over the northern Bahamas, which is associated with a broad surface low, has not changed much since yesterday.  The NHC states that upper level winds could become a little more conducive by Wednesday, and have now designated a MEDIUM (60%) probability of development during the next 5 days.

NHC 5 DAY GRAPHICAL TROPICAL WEATHER OUTLOOK
two_atl_5d0

At the time of analysis, the area of disturbed weather was designated INVEST 99L at 2:00 p.m. EDT.  The following information was available on INVEST 99L in the ATCF BTK 18Z product:

2:00 PM EDT Mon Oct 17
Location: 22.0°N 72.5°W
Moving: ESE at 10 mph
Min pressure: 1008 mb / 29.76 in
Max sustained: 30 mph

The 12 hour averaged motion yielded a 10 mph ESE direction.

Based on analysis of satellite loop imagery, the broad surface circulation has shown better definition.  Analysis of the 850 mb vorticity product from CIMSS indicated vorticity has increased at the 850 mb level.  Vorticity at the 925 mb level is still somewhat weak.

INVEST 99L SATELLITE LOOP IMAGERY
avn0-lalo-99l

rgb0-lalo-99l

Based on my analysis of the current wind shear forecast from the GFS model, the forecast is now showing upper level winds may begin to become more conducive for slow development by possibly Wed. evening, and become a little more favorable by Friday morning, with the sheared flow reversing to a small upper level anticyclone over the path the models indicate at the moment, albeit not optimal as far as upper level winds for significant development.  99L at the moment, is under some 40-50 kts of westerly shear.

GFS WIND SHEAR FORECAST
gfs_dl_shear_watl_17
CURRENT WIND SHEAR FROM CIMSS
wg8shr

Based on analysis of the GFS and ECMWF MSLP Normalized Anomaly maps, both are in good agreement of  99L continuing more toward the east, then beginning slow development.  The models then begin to move it N to NNW, and still insist on the system phasing with the approaching 500 mb trof.  This could start out as tropical in nature, however looking at the forecast upper pattern, I’m leaning toward sub-tropical at the moment.  If it phases with the 500 mb trof later on, it would become an extra-tropical feature (more of a baroclinic feature).

GFS SOLUTION
gfs_mslp_sig_watl_5
gfs_mslp_sig_watl_17

gfs_mslp_sig_watl_21

ECMWF 96 HOURS
ecmwf-96

Based on the current GFS solution, some effects may be felt along the Tidewater area, with the brunt over New England and NE U.S. area.  The ECMWF takes the system away from the U.S.  At the moment, forecast track based on the global pressure models should be considered preliminary until a definitive system becomes established.

I will continue to monitor this situation, but will not have another update until sometime on Wed.

Elsewhere, the disturbed weather I ave been monitoring in the extreme SW Caribbean Sea has diminished.  However, some convective activity remains over the area, and upper level winds are slightly conducive for development, should activity show an increase.  The GFS wind shear forecast indicates upper level winds may remain conducive over the area for the next 4-5 days.  I am going to monitor the area, for any significant changes.

CARIBBEAN SATELLITE LOOP IMAGERY
avn-l-caribbean

Elsewhere, Tropical Storm formation is not expected during the next 7-10 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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4 Responses to INVEST 99L FORECAST SYNOPSIS…ISSUED OCT. 17, 2016…3:40 P.M. EDT

  1. originallt says:

    Hi Storm, It’s Wed. about 10:30 am, still nothing much developing in the Bahamas.(At least on vis. Satellite). Do you think Otto will form?

  2. Port Aransas BeachBum says:

    Good for the fish – Good for us !

  3. Monty says:

    Thanks Storm. Looks like one for the fish?

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