N. GA is in a Moderate Risk for Severe Thunderstorms today. The Storm
Prediction Center rarely issues Moderate Risks for the CASI Region but
they are not unheard of. A Moderate risk means a Good chance of severe
thunderstorms in and close to the Risk area, with high thunderstorm
winds and possible tornadoes.
CASI Members should be on the alert today and remember to forward any
Storm Reports, Graphics, Photos, etc. of the storms to me for inclusion
on the CASI Web Site.
This weekend CASI will put a Storm Report Form on the Web through which
you can submit your reports but until then please e-mail me.
For those who can grasp the technical jargon, here are the specifics
from the SPC:
...TN VALLEY AREA...
WATER VAPOR IMAGERY AND PROFILER PLOTS SHOW A STRONG MID/UPPER
LEVEL LOW OVER NW OK...WITH EVIDENCE OF A SHORTWAVE TROUGH ROTATING
AROUND THE S SIDE OVER THE RED RIVER. THE 03Z MESOETA FORECASTS
THIS TROUGH TO PROGRESS EWD TODAY OVER THE NRN GULF STATES...AND
OVER THE CAROLINAS BY LATE TONIGHT. A SURFACE LOW ALSO OVER NW OK
SHOULD MOVE EASTWARD ACROSS AR/TN/KY JUST AHEAD OF THE MID LEVEL
TROUGH THROUGH THIS EVENING. E AND SE OF THE SURFACE LOW...LOW-
LEVEL MOISTURE ADVECTION WILL CONTINUE FROM THE S AND SW THROUGH
THE AFTERNOON HOURS. SURFACE ANALYSES THROUGH 10Z SHOW UPPER
60 DEWPOINTS ACROSS SRN AL/GA...AND AS FAR N AS NRN MS. THIS
MOISTURE SHOULD SPREAD NEWD TODAY AND RESULT IN SUBSTANTIAL
DESTABILIZATION OVER THE TN VALLEY. MAX TEMPERATURES OF 75-80 AND
DEWPOINTS OF 65-70 WILL SUPPORT MODERATE TO STRONG SURFACE-BASED
INSTABILITY /CAPE VALUES FROM 2000-3000 J/KG/.
INDICATIONS ARE THAT THE ONGOING WAA STORMS OVER NRN AL AND MIDDLE
TN WILL SPREAD E/NE DURING THE FIRST HALF OF THE DAY ON THE NOSE OF
THE MID LEVEL DRY SLOT. THIS SHOULD ALLOW SUFFICIENT TIME AND
BREAKS IN CLOUDS FOR SURFACE HEATING/DESTABILIZATION FROM
MID MORNING THROUGH MID AFTERNOON OVER NRN MS/AL AND TN IN THE WAKE
OF THESE STORMS. MEANWHILE...MID/UPPER LEVEL WLY WINDS WILL BE
INCREASING OVER THIS AREA...CONTRIBUTING TO STRONG DEEP LAYER SHEAR
FOR SUPERCELLS. ESTIMATED SRH VALUES RANGE FROM 250-500 M2/S2 OVER
MIDDLE/ERN TN AND NRN AL/GA DURING THE AFTERNOON/EVE...AND STORM-
RELATIVE WINDS THROUGH THE TROPOSPHERE ARE FORECAST TO BE
SUFFICIENT FOR SUSTAINED TORNADIC SUPERCELLS. BELIEVE GREATEST
THREAT FOR A FEW STRONG TORNADOES SHOULD BE FROM ABOUT 21-03Z E OF
THE SURFACE LOW ALONG THE WARM FRONT WHERE LOW-LEVEL WINDS WILL BE
BACKED...AS WELL AS IMMEDIATELY SE OF THE LOW ALONG THE REMNANT
DRYLINE/DEVELOPING COLD FRONT WHERE VERTICAL SHEAR WILL BE STRONG
AND SURFACE-BASED CAPE WILL BE MAXIMIZED.
...CAROLINAS...
EXPECT A CLUSTER OF POTENTIALLY SEVERE STORMS TO REACH UPSTATE SC
A FEW HOURS AFTER SUNSET...AND CONTINUE SPREADING EWD OVER SC/NC
DURING THE NIGHT. A NEW SURFACE LOW SHOULD DEEPEN LATE TONIGHT
ALONG THE SURFACE BAROCLINIC ZONE ACROSS CENTRAL SC/NC AS STRONG
WLY MID LEVEL FLOW SPREADS OVER THE SRN APPALACHIANS. THIS WOULD
FOCUS LOW-LEVEL MOISTURE ADVECTION/CONVERGENCE ALONG THE FRONT EAST
OF THE LOW OVERNIGHT...AND WOULD SUSTAIN A SEVERE THREAT ACROSS THE
ERN CAROLINAS THROUGH 04/12Z. THE PRIMARY SEVERE THREATS APPEAR TO
BE DAMAGING WINDS AND A COUPLE OF TORNADOES.
--
==============================================================
Jesse Ferrell - Meteorologist - j{at}weatherwatchers.org
Central Atlantic Storm Investigators - www.weatherwatchers.org
"A tornado? Why wasn't it dissipated by the weather
modification net?" --Jean-Luc Picard || ICQ No. 136862 ||