PRE-SEASON TROPICAL WEATHER DISCUSSION FORECAST SYNOPSIS…ISSUED 2:00 P.M. EDT…MAY 18, 2016

SEVERE WEATHER RISK: SLIGHT
TROPICAL CYCLONE FORMATION: MONITORING

Disclaimer:  This site is not affiliated with the National Hurricane Center, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(T. F. “Storm” Walsh III)

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Good day everyone!

SPC DAY 1 CONVECTIVE OUTLOOK
day1otlk_1300

TROPICAL WEATHER OUTLOOK DISCUSSION

Over the next 8-10 days, we have somewhat of a complex pattern forecast to evolve off the U.S. East Coast, and the Caribbean, Bahamas area.

First, closer to home, the MCS system that originated in the GOMEX yesterday, and crossed the Florida peninsula, has now emerged off the U.S. East Coast, with a 1011  mb low centered off the FL./GA. coast, with convection extending sown into the Bahamas.

Click on satellite images to access loops.

EASTERN U.S. SATELLITE LOOP
avn-lEAST

RAMSDIS FLOATER SATELLITE LOOP
tropical_ge_4km_visir2_floater_2

PENN STATE FLOATER LOOP
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Based on satellite loop imagery, the low can be clearly seen.  Analysis of the 850 mb vorticity map indicates strong vorticity near the lower levels.  The 925 mb vorticity product from the PSU e-WALL site was not available.  Analysis of vorticity at 700-500 mb indicates this low is tilted to the SE.

Based on analysis of the Cyclone Phase Evolution diagrams from FSU, this low is forecast to remain cold core.  Analysis of the current wind shear product from CIMSS indicates upper level winds are somewhat conducive at the moment and the low could become more discernible over the next 12 hours.  Albeit conditions are currently marginally favorable, I am not expecting this to take on sub-tropical characteristics, or develop into a sub-tropical storm given the global models take this quickly to the NNE to NE, and into increasingly strong SWLY shear in the current model runs.  The GFS and CMC GGEM did a good job on initialization of this early this morning, and are the only two that did.  Just FYI, this IS NOT the low that is forecast to develop off the DELMARVA area as mentioned in my previous forecasts.

CMC GGEM
cmc_mslp_uv10m_east_5

cmc_mslp_uv10m_east_6

I will continue to monitor this area in case any unexpected changes in the pattern occur.

The global models seem to be in excellent agreement of another area of low pressure to develop off the Eastern Seaboard, initiating in approximately 96 hours.  Based on the consensus of the global models (forecast times approximate), the low strengthens, and moves off quickly to the NE by 114 hours from 12Z this morning.  Between 114 – 120 hours in the period is where we encounter the trof split at 500 mb, associated with the surface low.  Both the GFS and ECMWF are in agreement on this.  The low which moves NE, leaves energy behind, with a new low forecast to develop (location approximate) east of the SC area.  This low is forecast to move in a general northerly to NNE direction, where it is forecast to phase with the 500 mb cutoff low.  Analysis of the 1000-500 mb thickness maps tends to indicate this feature may try to transition to warm core.  Based on analysis of the current wind shear forecast from the GFS, 200 mb streamlines will not be optimal, however 850-200 mb wind shear is forecast to relax over the low to around 10-15 mph.  This setup COULD allow for subtropical characteristics to begin, however given the fact the low will be associated with a 500 mb cutoff low, I would at this time, expect it to remain baroclinic in nature, more inline as a gale center.  The GFS keeps this offshore just enough to miss the U.S. directly, and the ECMWF has the center “clipping” Cape Cod.  Given the complex nature, I feel it will be better to monitor and handle this in real time.

GFS 84, 96, AND 147 HOUR FORECAST MAPS
GFS.84
GFS.96
GFS.147ECMWF 120, 144, AND 168 HOUR FORECAST MAPS
ECMWF.120
ecmwf.144ecmwf.168
GFS WIND SHEAR

GFS.WINDSHEAR
In regard to the trof split mentioned above, this is where we could possibly see some “mischief” either in the W. Caribbean or the northern Bahamas beginning in 8-10 days.  This scenario has been consistent with the ECMWF over the past 3 days and numerous runs.  The current ECMWF MSLP anomaly and 850 mb MSLP and wind speed indicate a “kink” or wave in the isobars as well as lowering surface pressure.  The NCEP ESRL 500 mb mean norm. anomaly map still indicates lowering of pressures over the Caribbean.

ECMWF MSLP ANOMALY MAP
ecm_mslpa_conus_11ECMWF 850 MB WIND SPEED AND MSLP
ecm_mslp_uv850_conus_11
NOAA ESRL PSD 500 MB MEAN NORM ANOMALY 240 HOURS
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I will be monitoring this area was we get close to that time in the forecast period.

Elsewhere, Tropical Storm formation is not expected during the next 7-10 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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8 Responses to PRE-SEASON TROPICAL WEATHER DISCUSSION FORECAST SYNOPSIS…ISSUED 2:00 P.M. EDT…MAY 18, 2016

  1. Greg goodman says:

    mr storm thankyou for the update.It looks like this is going to be a interesting hurricane season.

  2. dellamom says:

    Thanks for everything Storm. I hope the busy-ness of this next couple weeks does not indicate a pattern for the rest of the season.

  3. originallt says:

    Thanks Storm, agree 100% with your scenario with this second low. Most likely baroclinic in nature, a gale center rather than “tropical”. Also water temps. near the East coast still way too cold.

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