THERE IS A HIGH RISK OF SVR TSTMS OVER NORTHERN PORTIONS OF
MISSISSIPPI/ALABAMA AND NORTHWEST GEORGIA.
The SPC has issued a high risk for severe storms today for a portion of
the SW CASI area including
NW Georgia. The SPC issues only a handful of HIGH RISK's per year and
it is very rare for one to infringe on CASI territory. Southern CASI
residents should be on the alert for tornadoes, high winds, and very
large hail.
In addition from the SPC:
SURROUNDING THE HIGH RISK...THERE IS A MDT RISK OF SVR TSTMS OVER
EXTREME EASTERN ARKANSAS...NORTHEAST LOUISIANA...CENTRAL PORTIONS
OF MISSISSIPPI AND ALABAMA...WEST CENTRAL AND NORTHEAST GEORGIA...
SOUTHERN TENNESSEE...AND A SMALL PART OF WESTERN NORTH CAROLINA.
The SPC issues a number of MODERATE RISK's per year which are fairly
rare in the CASI Region. Again, CASI residents in these areas should be
on the alert for tornadoes, high winds, and very large hail.
In addition a SLIGHT RISK of Severe Storms is in effect for the rest of
the Carolinas and Georgia today.
As with any outbreak of severe storms, the damage today will not be
widespread over the SE US. The best way to keep up with where the
severe weather is and how it might affect you today is to listen to your
local NOAA WeatherRadio Frequency or your local radio or television
station, or the cable (non-DSS) Weather Channel.
If you're planning to record this severe weather event you should make
sure you have enough supplies to do so immediately. Severe
Thunderstorms have already fired this morning over TN and GA. Please
do keep an eye on the weather. Any storm reports that you might have,
please send to casilist{at}weatherwatchers.org or me at
j{at}weatherwatchers.org and I will forward the appropriate parts of your
post to the list. If you have video or photos after the storm please
put them up on your website or contact me so we can put your report up
on ours.
Specific information from the SPC follows for those of you who can read
the jargon.
...SOUTHERN STATES...
A SIGNIFICANT OUTBREAK OF SEVERE THUNDERSTORMS INCLUDING TORNADIC
SUPERCELLS IS EXPECTED TODAY INTO TONIGHT. THE MOST CONCENTRATED
AREA OF SEVERE INCLUDING A FEW INTENSE TORNADOES IS MOST LIKELY
FROM THE LOWER MISSISSIPPI RIVER VALLEY INTO SOUTHERN TENNESSEE AND
NORTHERN GEORGIA.
03Z MESOETA DOES NOT SHOW A WELL DEFINED WEST-EAST BOUNDARY
DEVELOPING OVER NORTHERN PORTIONS OF MISSISSIPPI/ALABAMA
/GEORGIA AS DID THE 00Z ETA. HOWEVER...LATEST SURFACE DATA DOES
SHOW WAVE OF LOW PRESSURE OVER NORTHEAST TEXAS WITH INCREASING
PRESSURE FALLS DOWNSTREAM OVER THE LOWER MISSISSIPPI VALLEY. IT
APPEARS THAT TAIL END OF CONVECTIVE LINE OVER SOUTH CENTRAL
TENNESSEE MAY PRODUCE A WEST-EAST OUTFLOW BOUNDARY THAT COULD HELP
FOCUS THUNDERSTORM DEVELOPMENT BY THE MIDDAY/EARLY AFTERNOON HOURS.
APPARENT DEVELOPMENT OF A CONVECTIVE CLUSTER OVER THE MID-SOUTH
EARLY THIS AFTERNOON ON THE MESOETA ADDS CONFIDENCE TO SCENARIO
DEPICTED ON 00Z ETA.
SOUTHERLY LOW LEVEL FLOW ALONG MUCH OF THE GULF COAST HAS ADVECTED
MOISTURE NORTHWARD OVERNIGHT. DEWPOINTS IN THE 60S AND LOWER
70S F ALREADY EXTEND AS FAR NORTH AS SOUTHERN TENNESSEE...AND
FURTHER MOISTURE TRANSPORT IS EXPECTED DURING THE DAY. MESOETA
FORECAST SOUNDINGS FOR 21Z INDICATE WIDESPREAD MODERATE INSTABILITY
WITH MLCAPE OF 2000-3000 J/KG.
MID LEVEL FLOW IS EXPECTED TO STRENGTHEN DURING THE PERIOD AS A
90-100 KNOT 500 MB WIND MAX ROTATES EAST FROM THE SOUTHERN PLAINS
TO THE MID-SOUTH BY WEDNESDAY EVENING. A BROAD AREA OF 70+ KNOT
500 MB WINDS SPREADING ACROSS THE SOUTHERN STATES WILL CREATE
STRONG DEEP LAYER SHEAR...WITH BRN SHEAR VALUES OF 50-100 M2/S2
BEING COMMON.
SOME CONCERN OVER THE WEAKER FORECASTS OF 0-3 KM STORM RELATIVE
HELICITY ON THE MESOETA VERSUS THE EARLIER ETA. HOWEVER...
LOCALIZED ENHANCEMENT OF LOW LEVEL VEERING OF WINDS WITH HEIGHT
NEAR THE WEST-EAST BOUNDARY AND POTENT COMBINATION OF INSTABILITY
AND DEEP-LAYER SHEAR SHOULD RESULT IN THREAT FOR SIGNIFICANT
SUPERCELLS/TORNADOES.
ONGOING STRONG/SEVERE CONVECTION MOVING ACROSS EAST TEXAS WILL
LIKELY CONTINUE INTO THE LOWER MISSISSIPPI VALLEY DURING THE
MORNING HOURS...WITH INTENSIFICATION AND ADDITIONAL DEVELOPMENT
EXPECTED BY THE MIDDAY/EARLY AFTERNOON HOURS.
...OHIO RIVER VALLEY AREA...
CONFIDENCE SOMEWHAT LOWER ON SEVERE THREAT IN THIS AREA. STRONG
VERTICAL WIND SHEAR/DYNAMICS IN LEFT EXIT REGION OF 90-100 KNOT
500 MB SPEED MAX AND FORECAST MESOETA MLCAPE OF 1000-1500 J/KG ARE
INDICATED. DESPITE BEING NORTH OF POSSIBLE WEST-EAST CONCENTRATION
OF SEVERE THUNDERSTORMS FARTHER SOUTH...ADDITIONAL SEVERE
DEVELOPMENT IS POSSIBLE FROM KENTUCKY INTO EXTREME WESTERN
PENNSYLVANIA DURING THE AFTERNOON AND EVENING HOURS.
--
==============================================================
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 ||