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Special Weather Briefing: Isaac 08/29/2012 www.srh.noaa.gov/shv/briefing. Brandi Richardson Meteorologist. National Weather Service Shreveport, Louisiana. Isaac Summary. Uncertainty Official Isaac Forecast Even further west Slowed movement H igher risk for heavy rainfall Model Data
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Special Weather Briefing:Isaac08/29/2012www.srh.noaa.gov/shv/briefing Brandi Richardson Meteorologist National Weather Service Shreveport, Louisiana
Isaac Summary Uncertainty Official Isaac Forecast Even further west Slowed movement Higher risk for heavy rainfall Model Data Several models still on a more westward track Largest impacts over N LA/S AR, but impacts into E TX/SE OK National Weather Service Shreveport, Louisiana
Official NHC Track Forecast Tuesday morning Latest track forecast (shifted west)
Official Rainfall Forecast 2-4” 4-7” 1-2” Locally higher totals may be possible
Official Forecast Impacts: Flooding • N LA • Greatest risk for flooding • Wed PM-Fri AM • S AR • 2nd greatest risk area • Early Thu AM-Fri PM • Extreme E TX • Wed PM-Fri AM • Elevated risk Flash Flooding Possible
Official Forecast Impacts: Winds 9 PM Wed Tropical Storm force winds • N Central LA • ~40-45 mph • Wed night-most of Thu • SW AR/SE OK • 15-20 mph • Thu • Deep E TX • 20-25 mph • Late Wed PM – most of Thu • E TX • 10-15 mph • Thu 7 AM Thu
Official Forecast Impacts: Tornadoes • N Central LA/S AR • Most at risk • Quick spin-ups • Not much lead time • Elsewhere • Can’t rule it out, but very low risk Thu AM – Fri AM
Watches/Warnings/Advisories Flash Flood Watch 7 AM Thu - 7 PM Thu Topical Storm Warning Flash Flood Watch 7 PM Wed - 1 PM Thu
Westward Potential 7 AM Friday 7 PM Thursday
Westward Case Rainfall 6-8” 2-4” 4-6” Through Saturday morning
Potential Impacts • More westward track: • N LA/S AR • Heavy rainfall/flooding (5-10”) • Greatest impact timeframe: Thu/Thu PM • Winds 40-45 mph with higher gusts Wed PM-Thu PM for N/LA; ~25 mph with higher gusts for S AR • Prime tornado threat area • E TX/SE OK • Rainfall: 2-4” isolated 5” • Winds 25-35 mph with higher gusts Thu AM-Thu PM • Tornado threat along eastern-tier counties in E TX
Official NHC Track Forecast ( Friday Morning through Saturday)
NEXT CONFERENCE CALL: Today August 29, 2012 @ 5:30 PM www.srh.noaa.gov/shv/briefing National Weather Service Shreveport, Louisiana