SPECIAL TROPICAL WEATHER OUTLOOK FORECAST SYNOPSIS…SUB-TROPICAL DEVELOPMENT LIKELY…ISSUED MAY 03, 2015…8:40 P.M. EDT

SEVERE WEATHER RISK: SLIGHT
TROPICAL STORM FORMATION:  LOW

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.

This office is now switching to Tropical Weather Forecast mode.  I will try, if time allows, to include severe weather, however, the added analyses would consume more time than I’d prefer, making my synopsis post later in issuance.  Please refer to the Storm Prediction Center website home page for severe weather information in the interim.

SPC HOME PAGE GRAPHIC (LINKED)
day1otlk-overview

The NHC in Miami, FL. has issued a Special Tropical Weather Outlook regarding the possible development of the system I have been speaking of over the past few days.  Currently, the NHC has designated a LOW (30%) chance of development of a subtropical system during the next 5 days IVO the northern Bahamas area.

NHC 5 DAY GRAPHICAL TWO
two_atl_5d1

Based on analysis of the global models, and regional DGEX, consensus appears to be a development will initialize on Wed., May 06, 2015.  The majority of the models indicate if development occurs, that the system will be slow to move.  This solution is in response to ridging forecast to be north of the system, which will try to inhibit northward motion.

Given the suggested slow movement, track forecast is going to be difficult.  I believe the key to where this may wind up is, how far in or away from the coast development occurs.  Right now, it looks if development occurs closer toward the coast than shown in the NHC graphic, chances for a landfall are more probable.  I am basing this on the premise that the system is forecast only to be of minimal sub-tropical storm status, and will be guided by low level steering.  Modeling suggests at this time, that 850mb heights will be slightly stronger directly north of the system, and weaker toward the west on some of the models.  This situation “could” draw whatever develops, slowly toward the coast.  On the other hand, if the system remains stationary for as long as projected by a couple of the models, and further east, once the ridge/trof setup begins to progress, the blocking pattern would be eroded by the trof approaching from the west, and carry the system toward the NE.  So at this particular moment, it’s useless to try and speculate on “any” definitive direction, at least until development occurs and we see what we have.

ECMWF 144 HOURS
ECMWF 144
DGEX / GFS 850 MB WIND
etaavn.850wind138
GFS
GFS.144
CMC
CMC 144
FIM SEUS
wind_10m_f132

NCEP / EMC CYCLOGENESIS AND TRACKING (48-120 HOURS)
genprobFNMOC.feperts.2015050312.altg.048_120
genprobMULTI.4enscon.2015050312.altg.048_120
genprobNCEP.aeperts.2015050312.altg.048_120

This is suggested by the models to transition to warm core, most likely shallow, and should remain subtropical as indicated by the forecast wind field of the maximum winds located away from the center.  The ECMWF currently shows dissipation by Sunday, a few hundred miles off the SEUS coast.  Once the models have something to latch onto, we should see closer agreement in solutions as far as strength and track.  Both the CMC and GFS wind shear forecast indicates upper level winds may become slightly favorable over the next few days.

CMC / GFS WIND SHEAR FORECAST
cmc850200shear25
GFS.850200shear20

So at this moment, residents along the coastal areas from GA to NC should monitor the situation during the next 5 days.

I should be updating tomorrow and Tuesday, but may not be available until Friday, due to a temporary change in my schedule at work.

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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One Response to SPECIAL TROPICAL WEATHER OUTLOOK FORECAST SYNOPSIS…SUB-TROPICAL DEVELOPMENT LIKELY…ISSUED MAY 03, 2015…8:40 P.M. EDT

  1. originallt says:

    Thanks, Storm. We’ll be watching!

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