Tornado Threat
Posted by
JAC on 7/29/2011, 5:55 pm

MESOSCALE DISCUSSION 1785 NWS STORM PREDICTION CENTER NORMAN OK 0313 PM CDT FRI JUL 29 2011 AREAS AFFECTED...PORTIONS COASTAL S TX. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 292013Z - 292245Z TORNADO POTENTIAL...WHILE INITIALLY QUITE MRGL...MAY INCREASE DURING REMAINDER AFTERNOON AND EVENING ALONG PORTIONS TX COAST AS CENTER OF TS DON NEARS PROJECTED LANDFALL. PER NHC FCSTS...CENTER SHOULD CONTINUE TO APCH COAST BETWEEN BRO-CRP. ONCE CENTER GETS TO WITHIN ABOUT 20-30 NM OF LANDFALL...LEADING PORTION OF MOST KINEMATICALLY FAVORABLE SECTOR OF SYSTEM WILL BEGIN TO SPREAD ONSHORE TO ITS N...INCREASING IN COVERAGE WITH TIME AS DON TRANSLATES PROGRESSIVELY FARTHER INLAND. GRADUAL ENLARGEMENT OF LOW-LEVEL HODOGRAPHS IS EVIDENT IN CRP ALREADY...AND WILE STILL TOO SMALL TO SUPPORT SUSTAINED SUPERCELL STRUCTURES...IS EXPECTED TO RAMP UP PACE OF INCREASE IN 0-1 KM AGL SHEAR FROM NOW THROUGH POST-LANDFALL PHASE. MAIN LIMITING FACTORS WILL BE 1. SPATIAL...GIVEN SMALL RADII OF FAVORABLE LOW-LEVEL FLOW/SHEAR IN THIS SYSTEM. THIS WILL GREATLY LIMIT LOW-LEVEL VERTICAL SHEAR AVAILABLE TO CONVECTION WELL NE OF CENTER--INCLUDING OUTFLOW-DOMINANT/MULTICELLULAR ACTIVITY NOW OBSERVED ACROSS MID-UPPER TX COASTAL PLAIN. SHEAR THERE IS NOT EXPECTED TO INCREASE GIVEN PATH OF CENTER PASSING ABEAM/AWAY FROM AREA WITH TIME. 2. MODAL...WITH LACK OF CONVECTIVE COVERAGE IN REGION OF MOST FAVORABLE LOW-LEVEL SHEAR NNW THROUGH SE OF CENTER. AS SUCH...IT IS NOT YET CLEAR THAT THREAT WARRANTS TORNADO WW...BUT WILL CONTINUE TO MONITOR CONVECTIVE AND ENVIRONMENTAL WIND TRENDS FOR POSSIBLE ISSUANCE LATER TODAY. REF NHC ADVISORIES FOR LATEST GUIDANCE ON FCST TRACK/INTENSITY OF DON. ..EDWARDS.. 07/29/2011 |
50
In this thread:
When Don belches everyone must be listening -
JAC,
7/28/2011, 10:05 pm- Tornado Threat - JAC, 7/29/2011, 5:55 pm
- Super Rapid Scan - JAC, 7/29/2011, 4:38 pm
- POPs - JAC, 7/29/2011, 10:31 am
- Land interaction. - JAC, 7/29/2011, 9:29 am
- Re: When Don belches everyone must be listening - JAC, 7/29/2011, 9:21 am
- Brownsville NWS Radar - JAC, 7/29/2011, 7:48 am
- Re: When Don belches everyone must be listening - JAC, 7/29/2011, 7:43 am
- Re: When Don belches everyone must be listening - Jake, 7/28/2011, 11:30 pm
- You tell me - JAC, 7/28/2011, 10:40 pm
Post A Reply
This thread has been archived and can no longer receive replies.