Daweathablog

Charles E. Roop giving his own forecasts, weather discussions, photos and adventures for the Starkville, MS area, Florida, and beyond.

Sunday, April 25, 2010

Slight Severe Weather Threat Today

The SPC has continued labeling north and central Florida as a slight risk category for today and tonight. The dynamics look decent, but there are a few limitations to the threat.

Skew-T (upper-air sounding) from Jacksonville at 8 am ET (Source: Unisys Weather)

The KJAX skew-t (shown above) gives a snapshot profile of the air above the surface. Shear profiles look good and, according to NWS-JAX, helicity values look good for possible rotation. The lifted index is about -2, which is slightly decent for severe weather formation. There are moist conditions at the surface, but dry at about 900 mb and higher. This might be a sign of convective instability but we would need some daytime heating to get things going. The SPC mesoscale analysis does hint at divergence over the area, which is another factor for making things unstable.

However, the NWS is noting low lapse rates as a limiting factor. Also, the cloudcover over northern Florida would limit daytime heating in the area. However, that could change later on.

Florida visible satellite image (Source: WeatherTap.com)

As for timing and arrival, NWS-JAX wrote this at 9:38 this morning...
THE LINE IS EXPECTED TO SPLINTER AS IT APPROACHES THE COAST THIS AFTN...THEN REDEVELOPMENT OCCURS ACRS THE SRN PORTION LATER IN THE AFTN AS STORMS MOVE IN DIRECTLY FROM THE GULF. EVEN SO THE COASTAL ZONES AND REMAINDER OF NE FL ARE NOT OUT OF THE WOODS AS STRONG TO SEVERE STORMS ARE POSSIBLE AND RISK FOR TORNADOES STILL EXISTS.
Based on the sounding and profile readings, storm motion should be out of the west-southwest at about 30-40 knots.

So, it's a wait and see. Keep an eye on the Twitter feed during the day as I try to both watch this and study for a physics final exam. Stay tuned.

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