Saturday, April 24, 2010

""HIGH RISK"" FOR SEVERE WEATHER IN SOUTHERN USA



METD WEATHER
AKSHAY DEORAS
EXTREME WEATHER FORECASTER,

CONCERNING- HIGH RISK FOR TORNADOES AND OTHER SEVERE WEATHER EVENT

IMMEDIATE ACTION REQUIRED
SPC AC 240557

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT SAT APR 24 2010

VALID 241200Z - 251200Z

...THERE IS A HIGH RISK OF SVR TSTMS PORTIONS SERN AR...NERN
LA...MS...CENTRAL/NRN AL...

...THERE IS A MDT RISK OF SVR TSTMS ELSEWHERE FROM PORTIONS E TX TO
CENTRAL/NRN LA...AL...WRN GA...TN...SRN/CENTRAL KY...EXTREME SERN
MO...CENTRAL/SRN/ERN AR....

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING MDT RISK...FROM
GULF COAST OF SE TX TO FL PANHANDLE...TO PORTIONS WV/OH...TO
PORTIONS LOWER MO VALLEY REGION...TO E TX....

OUTBREAK OF NUMEROUS SVR TSTMS IS EXPECTED TODAY...GREATEST
CONCENTRATION/INTENSITY OF WHICH SHOULD INCLUDE STG-VIOLENT TORNADO
THREAT AFFECTING MID-SOUTH...MS DELTA REGION...AND TN VALLEY.

AT THE MID AND THE UPPER LEVELS, A SPLIT FLOW TYPE OF PATTERN IS SEEMING TO BE MOVING NORTHWARDS TOWARDS LA,AR,MS,AL AREAS. THERE WILL BE STRONG UPPER LEVEL JETS ALOFT AND SORT OF CYCLONE INDUCED LLJ WILL FIRE OVER PARTS OF CENTRAL TX MOVING TO THESE AREAS. WITH ALREADY HIGH CAPE TO INSTENSIFY THE UPDRAFTS AND EXTREMELY HIGH VERTICAL SHEAR, CONVECTION WILL BE TORNADOGENESIS VERY SOON AS THE 60KT LOW LEVEL JETS ARRIVE IN WARM AND MOIST PROFILE. IN THE MORNING HOUR PATTERN AS THE SETUP DRAGS NORTH, A DEFINED 15% RISK OF TORNADO LIES OVER PARTS OF CENTRAL AR,LA. AN EMBEDED CYCLONIC CIRCULATION WINDS WILL RAPIDLY INTENSIFY CREATING MORE FAVOURABLE WIND PROFILES DUE TO DEEP SHEARS IN THE O-1 KM FIELD, SUPERCELLS WILL EXPLODE OVER EASTERN ARKANSAS, MAINLY NEAR MS VALLEY AND ALBANIA REGION. MOISTURE SEEMS TO BE PLENTY WITH SFS DEWPOINT LEADING TO 70F, CONVECTION WILL BE HIGH DUE TO CAPE AND MOISTURE RICH ENVIRONMENT.

BY 08Z+08z RUC,
60KT LLJ WILL PROGRESS MORE INSIDE RAPIDLY BRINGING MOISTURE AND CAUSING HIGH LEVEL CONVECTION. A PROGRESSING COLD FRONT WILL DRIVE IN WITH THE WARM FRONT INTERSECTING IT AT NORTHERN MS. THIS WILL LEAD TO AN EXTREME UNSTABLE CONDITIONS AND MOST FAVOURABLE FOR TORNADOES. THE WARM FRONT IS SETTING OVER NRN MS. WITH THE DRIVING COLD FRONT INTERSECTING IN 8HRS AND SO, TORNADOES ARE LIKELY TO FORM AND THE EHI VALUES WILL BE ABOVE 3.0 THROUGHOUT THE EVENT.

SPC HAS ISSUED WEATHER STATEMENT AND HAS UPGRADED TO HIGH RISK
DUE TO COOL AIR ALOFT, HAILS ARE ALSO POSSIBLE WITH SPC GIVING 15% RISK
STAY TUNED FOR ALERTS AND BE PREPARED FOR THE EXTREME

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