SEVERE WEATHER / TROPICAL WEATHER OUTLOOK FORECAST SYNOPSIS…ISSUED MAY 20, 2015…11:05 A.M. EDT

SEVERE WEATHER RISK: SLIGHT
TROPICAL STORM FORMATION:  NONE

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 day everyone!

The Storm Prediction Center (SPC) Norman, OK. has designated SLIGHT risk of Severe Thunderstorms across parts of the PERMIAN BASIN AND SW TO CNTRL TX…

There is a MARGINAL risk across parts of the SRN PLAINS…ARKLATEX…LOWER TO MID MS VALLEY…WRN TN VALLEY AND GULF COAST STATES…

SPC DAY 1 CONVECTIVE OUTLOOK
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Based on analysis of F5 DATA Severe Weather software this morning, utilizing the NAM-WRF forecast soundings, the best chance of severe weather may extend somewhat further into a portion of eastern TX.  The most potent and probable severe threat should lie within the slight risk area.  Forecast sounding indices end to indicate more of an environment for multi cellular storms early on.  Indices indicate a very good probability for hail, and damaging severe thunderstorm gusts.  This is based on the forecast sounding values from earlier this a.m. as follows:

SBCAPE: 3000-4000 j/kg
MLCAPE: 2000-3000 j/kg
LIFTED INDEX: -8 to -10
CRAVEN BROOKS INDEX: 30,000 to 60,000+

These values indicate a very unstable environment with sufficient lift for hail.

Analysis of various tornado parameters in the forecast soundings indicate the best probability for tornadoes lies within the slight risk zone from early afternoon into early evening, however some isolated activity could occur outside the slight risk zone, and is depicted in the following outline.

F5 DATA NAM-WRF BEST TORNADO PROBABILITY
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Residents within the risk areas should monitor NOAA Weather Radio and local NWS statements and warnings this afternoon into evening. 

The following graphics are linked to their respective sites.  You will need to click on them for the most current information.

SPC CONVECTIVE WATCH DISPLAY
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SPC MESOSCALE DISCUSSIONS DISPLAY
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NWS DOPPLER RADAR
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NWS HAZARD, WATCH AND WARNING DISPLAY (LINKED)

TROPICAL WEATHER SECTION FOR THE ATLANTIC, CARIBBEAN SEA AND GULF OF MEXICO:

The tropics remain quiet again this morning.

The area of disturbed weather I mentioned yesterday just north of western Panama is moving very slowly into the EPAC.  Satellite loop imagery from RAMSDIS this morning shows there could be some slight cyclonic turning beginning.  A wind shift was noted in the surface station overlay.

NOAA TROPICAL ATLANTIC SATELLITE LOOP

RAMSDIS SATELLITE FLOATER IMAGE LOOPS

Just for giggles and grins, the GFS once again is bringing a solution of another sub-tropical low developing in the southern Bahamas in about 2 weeks.  Do I think at the moment this is erroneous?  Yes.  Can it be totally ruled out?  No.  I will be watching the model for consistency since it did well with ANA, and will look for other models solutions as time goes on. 

GFS 360 HOUR
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GFS 384 HOUR
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1000-500GFS.384

I will not be available during the next 3 days for forecasting,  due to my work schedule

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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