SUB-TROPICAL STORM MELISSA FORECAST SYNOPSIS…NOV. 18, 2013…ISSUED 12:55 P.M. EST…PHFC

DONATIONS NEEDED
Funny dog holds dollars in mouth, isolated white background

Good day everyone!

There is NO SEVERE WEATHER  forecast over the next 4-8 days.
Yesterday’s storm reports indicate a total of 82 Tornadoes during the outbreak via the unfiltered report.  The filtered report indicated only 69 Tornadoes:

SPC PRELIMINARY UNFILTERED STORM REPORTS

SPC FILTERED STORM REPORTS

Unfiltered: On March 8, 2011, the SPC started providing unfiltered storm reports by removing space/time filtering on incoming National Weather Service (NWS) Local Storm Reports (LSRs). This approach is consistent with NWS storm-based verification methods. However, identical reports are removed from SPC logs and should not appear on the preliminary maps and lists.

 

Filtered: The space/time filtering had been used by SPC in an attempt to reduce duplicate reports and limit artificially inflated initial estimates of severe weather events when many reports arrived for the same event. The filtering is applied to each of the tornado, hail and wind reports separately.

 

The logic implemented for filtering is as follows:

 

  1. Same county and state
  2. Same regular expression of deaths/fatalities
  3. Spatial/Temporal differences between pairs
    1. Less than 5 miles and 5 minutes for tornadoes
    2. Less than 10 miles and 15 minutes for hail and wind reports. (the higher wind speed and larger hail size reports are kept.)

The filtering logic is applied to tornado, hail and wind reports separately. For example, a tornado report and hail report for the same location and time are kept in their respective reports.

Disturbance INVEST 98L has acquired enough solid convection on the edge of the broad LLC this morning, and has been designate Sub-Tropical Storm (STS) Melissa.  As of the 11:00 a.m. EST advisory from the NHC in Miami, the following information was available on Melissa:

11:00 AM EDT Mon Nov 18
Location: 29.3°N 53.6°W
Moving: NW at 9 mph
Min pressure: 987 mb / 29.15 in
Max sustained: 50 mph

MELISSA FLOATER SATELLITE LOOP IMAGERY

NWATL SATELLITE LOOP 

HURREVAC STS MELISSA TRACKING MAPS
MELISSA 72 HOUR

MELISSA ERROR CONE

MELISSA WIND TAGS

Melissa is currently moving toward the NNW, and I expect this motion to continue for the next 24-30 hours, before an approaching trof turns her toward the NNE.  Melissa should remain over the open Atlantic posing no threat to the U.S., based on analysis of current forecast steering layers maps.  I agree with the NHC forecast track, which is in line with Model Guidance, matching closely to the TVCN / TVCC / and AEMI (GEFS ADJUSTED CONSENSUS).

MELISSA 12Z DYNAMIC MODEL TRACK GUIDANCE
12zatcfearlybestMELISSA

Analysis of the wind shear forecast from the GFS 06Z run indicates as outlined in the NHC forecast discussion, upper level winds may become more conducive as the semi 200 mb ridge is forecast to become a brief, small upper level anticyclone in about 30 hours, which would allow for further intensification, and the good possibility of allowing Melissa to become tropical, just prior to her crossing into cooler sst’s  to her North.  There also remains the possibility of Melissa attaining hurricane status for a brief period of about 24 hours, indicated by the SHIP and DSHP intensity forecast models.  Based on this analysis, I agree with the NHC forecast intensity of Melissa reaching strong tropical storm status, with the brief probability of her attaining CAT 1 Hurricane status.

AMSU imagery does indicate that Melissa is a warm core system.

AMSU DATA

Atlantic shipping interests should monitor this storm closely, and plan evasive action.

I will continue to monitor Melissa for any significant changes over the next 72 hours.

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

Have a blessed day!

T. F. “STORM” WALSH III 
GMCS, USCG (ret) 
METEOROLOGIST / HURRICANE SPECIALIST 
MEMBER WEST CENTRAL FL AMS  
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced) 
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 SUB-TROPICAL STORM MELISSA FORECAST SYNOPSIS…NOV. 18, 2013…ISSUED 12:55 P.M. EST…PHFC

  1. Monty says:

    Thanks Storm. Thanks for the explanation on filtered/unfiltered. Damn…you know it all!! Melissa seems to be holding her own…curious if she will become tropical and become a Hurricane. For such a boring season…it refuses to go away.

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