Possible Severe Weather This WeekendMarch 8th, 2013 at 12:36 pm by markmonstrola under Weather
From the Austin/San Antonio NWS office:
..Isolated Severe Thunderstorms Saturday Night Into Early Sunday…
AREA OF CONCERN…Locations along and north of Interstate 10, including the Austin and San Antonio metro areas.
IMPACTS…Large hail (up to golf-ball size) and damaging winds around 60 mph.
TIMING…Some storms could develop by 6 pm, but the main period will be 9 pm to 3 am.
DISCUSSION….A low pressure system and associated cold front will reach the western parts of our area by 6 pm,
then move west to east through the rest of South Central Texas between 9 pm and 3 am. Moist, unstable air will be
lifted by the front and produce a line of showers and thunderstorms. There is enough wind shear for some storms to
produce severe hail (1 inch or greater in diameter) and damaging winds (58 mph or greater). Rainfall amounts will
range from 1/4 inch or less west of U.S. 83 to 1/4 to one inch east of U.S. 83. A few spots east of metro Austin
may get two inches.
Here is the latest discussion from our friends at the Storm Prediction Center located in Norman, OK:
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF TX... ...SYNOPSIS... AN UPPER LOW/SHORT-WAVE TROUGH -- PART OF LARGER TROUGH COMPRISED OF PHASED NRN AND SRN STREAM COMPONENTS -- IS FORECAST TO SHIFT NEWD OUT OF THE SRN ROCKIES AND INTO/ACROSS THE CENTRAL PLAINS REGION THROUGH THE PERIOD. AS THIS OCCURS...A SURFACE LOW /INITIALLY OVER ERN CO/WRN KS/ AND ASSOCIATED COLD FRONT /INITIALLY TRAILING SWD ACROSS THE TX/OK PANHANDLES AND THE TRANSPECOS REGION OF W TX/ WILL SHIFT EWD INTO THE CENTRAL AND SRN PLAINS. BY SUNSET...EXPECT THE LOW TO BE APPROACHING CENTRAL KS WITH THE COLD FRONT SWEEPING INTO CENTRAL OK AND NWRN TX/THE HILL COUNTRY...AND THEN CONTINUING EWD ACROSS THE PLAINS OVERNIGHT. THIS FRONT WILL FOCUS PRECIPITATION/CONVECTION ACROSS THE CENTRAL PORTION OF THE COUNTRY -- INCLUDING SOME POTENTIAL FOR SEVERE WEATHER FROM KS SWD TO TX. ...SRN PLAINS... ANY CONVECTION ONGOING AT THE START OF THE PERIOD ACROSS WRN OK/NWRN TX SHOULD BE SUB-SEVERE...AND IS LIKELY TO FURTHER WEAKEN THROUGH THE DAY. MEANWHILE...MODEST DESTABILIZATION WILL COMMENCE AHEAD OF THE ADVANCING COLD FRONT...WITH SURFACE-BASED CAPE LIKELY TO REACH THE 500 TO 1000 J/KG RANGE FROM SRN OK SWD ACROSS THE TX HILL COUNTRY BY LATE AFTERNOON. ATTM...IT APPEARS THAT STORM RE-INITIATION WILL OCCUR ACROSS NWRN TX -- AND POSSIBLY NWD INTO CENTRAL OK -- INVOF THE FRONT IN THE 21Z TO 23Z TIME FRAME...WITH STORMS THEN DEVELOPING SWWD ALONG THE FRONT INTO THE EVENING. WITH LOW-LEVEL VEERING OF THE FLOW FIELD TOPPED BY SWLYS INCREASING WITH HEIGHT TO 60-PLUS KT AT MID LEVELS...SHEAR WILL BE SUPPORTIVE OF ORGANIZED/SUPERCELL STORMS. HOWEVER...WITH CAPPING LIKELY TO CONFINE MUCH OF THE CONVECTION TO THE FRONTAL ZONE -- AND THUS LINEAR ORGANIZATION LIKELY TO PREDOMINATE -- EXPECT LOCALLY DAMAGING WINDS AND HAIL TO BE THE MAIN THREATS. THOUGH THE THREAT SHOULD DIMINISH INTO THE EVENING...SOME SEVERE POTENTIAL -- ESPECIALLY IN THE FORM OF HAIL -- MAY LINGER ACROSS CENTRAL TX AND SWWD TOWARD THE DEL RIO/COTULLA/LAREDO REGION.