POSSIBLE SUB-TROPICAL DEVELOPMENT?…FORECAST SYNOPSIS…ISSUED APR. 28, 2015…8:00 P.M. EDT

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.

Good evening everyone.

First, KUDOS to my friend and fellow forecaster Rob Lightbown of Crown Weather for picking up on this, as I just got on tonight to look at model runs.

Based on model analysis of the ECMWF, GFS, CMC, and FIM 8 global models, it seems that the models are sniffing out a “POSSIBLE” Sub-Tropical entity developing in an area anywhere from the NW Bahamas, to off the NC/SC area by Wed., May 6.

ECMWF (240 HOURS)
ECMWF 240
GFS
GFS.18Z
CMC
CMC 186
FIM 8 (CENTERED IN WHITE CIRCLE)
FIM

Before anyone gets all excited, this isn’t concrete as of yet, as it appears the models have only latched on in the last 2 runs.  A breakdown of the models shows the ECMWF developing an inverted trof just above the NW Bahamas, and developing a very weak area of low pressure which moves to a position a few hundred miles off the VACAPES area to the east by Fri. May 08.

The GFS and CMC are both a little more bullish, with a stronger low, and keep the low much closer to the coast before moving away in the vicinity of the VACAPES.

The FIM 8 model starts this out in the same area, but with a much slower solution at the moment.

So, position and timing are pretty much split at the moment, and albeit this usually occurs at initialization, and is at least 7 – 8 days out, it is a little unusual for 4 models to agree this early in the initialization stage of developing a low in or near the same location.

Analysis indicates IF this does come to fruition, it could be a SubTropical low, as the ECMWF, GFS and CMC are trending toward a “warm core” low, with the strongest surface winds out and away from the center.  One item that keeps me a little hesitant on this however, is the current wind shear forecast, which is only going out to 180 hours at the moment, albeit the CMC did show a trend of a possible upper level anticyclone trying to establish itself, and the GFS in the last frame of the run, showing somewhat of a decrease beginning in shear in that time frame.

I want to see if the models remain consistent on this in further runs, and see what pans out with the wind shear forecast.

In any event, just a little “heads up” in case something does pop up next week.

I’ll be looking at this again sometime tomorrow, but won’t be able to update probably until the afternoon.

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 POSSIBLE SUB-TROPICAL DEVELOPMENT?…FORECAST SYNOPSIS…ISSUED APR. 28, 2015…8:00 P.M. EDT

  1. Mac says:

    I’ll echo what Dellamom complements you on, Storm! We had 5 confirmed tornados in the storms that passed through SE Louisiana on Monday. 3 EF-1’s, and 2 EF-0’s. All within a 50 mile radius of New Orleans. Fortunately, none over here on the North shore of Lake Ponchatrain! I was out on my back porch Monday morning watching the 80 foot + pine trees in my back yard dancing around in the wind gusts!

  2. dellamom says:

    Storm, your vigilance on our behalf is comforting. I truly appreciate that your other commitments make this a “labor of love” for you on our behalf. Also, didn’t we have something like this last year (or the year before)? I remember typing “but it’s not June yet!” before now.

  3. originallt says:

    Thanks Storm, and thanks for the “Heads up”!

  4. Thanks so very much for the kudos, really appreciate it. All of the models have been showing this possibility consistently since Saturday when I started mentioning it. It’ll be interesting to see if the models end up verifying or if this ends being another “phantom storm”.

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