dan11295 Posted August 28, 2012 Share Posted August 28, 2012 12 GFS doesnt even bring it onshore until late tomorrow evening after having in crawl westward along the coast for a day. Moves the heaviest rain west toward BR. Link to comment Share on other sites More sharing options...
battlebrick Posted August 28, 2012 Share Posted August 28, 2012 dropsonde 75 mph at surface, 100+ at the higher levels special advisory incoming most likely i would just like to point out the 100+ mph readings are less than 2000 ft above the surface Link to comment Share on other sites More sharing options...
Max Posted August 28, 2012 Share Posted August 28, 2012 Since the waters south of the LA coast are still averaging 30C and with near perfect ULL conditions other than the dry air, do any Mets think that the Dmax tonight actually might be something if Isaac can expel the dry air that made it into the core already? Link to comment Share on other sites More sharing options...
Dsnowx53 Posted August 28, 2012 Share Posted August 28, 2012 Looks like that 12z Euro run from this past Thursday might be close to reality after all. If the weakness was really going to pick this thing up, it would have taken Issac to the NE much earlier. The track just E of MSY never made much synoptic sense to me, considering the proximity and strength of the ridging. We are at the shelf waters essentially, so a rapid blow up in intensity is unlikely, but as we've said for a while, we just need the core to tighten up and we can easily reach solid cat 1 strength, given the very low pressures...maybe even weak cat 2...I can't take that possibility off the table just yet, although at this point it's unlikely. But this might still have another 24+ hours over water, rendering it hard to completely throw a strong cat 1/weak cat 2 out the window. Link to comment Share on other sites More sharing options...
turtlehurricane Posted August 28, 2012 Share Posted August 28, 2012 Anyone else thinking coastal convergence could really tighten Isaac up? Link to comment Share on other sites More sharing options...
phil882 Posted August 28, 2012 Share Posted August 28, 2012 dropsonde 75 mph at surface, 100+ at the higher levels special advisory incoming most likely i would just like to point out the 100+ mph readings are less than 2000 ft above the surface Not factually true... the altitude is more around 4,000 ft from the aircraft... you were probably looking at metric units Link to comment Share on other sites More sharing options...
Derecho! Posted August 28, 2012 Share Posted August 28, 2012 12Z UKMET has Isaac stationary, just offshore, from 0Z tonight to 12Z tomorrow morning. Link to comment Share on other sites More sharing options...
SmokeEater Posted August 28, 2012 Share Posted August 28, 2012 Just upgraded 75 mph, 975mb. Link to comment Share on other sites More sharing options...
RGweathergeek Posted August 28, 2012 Share Posted August 28, 2012 Finally, special advisory at 11:20 AM Central from NHC: 000 WTNT64 KNHC 281618 TCUAT4 HURRICANE ISAAC TROPICAL CYCLONE UPDATE NWS NATIONAL HURRICANE CENTER MIAMI FL AL092012 1120 AM CDT TUE AUG 28 2012 ...RECONNAISSANCE DATA INDICATE ISAAC FINALLY ACHIEVES HURRICANE STATUS... REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT MAXIMUM WINDS ASSOCIATED WITH ISAAC HAVE INCREASED TO 75 MPH...120 KM/H. ON THIS BASIS...ISAAC IS BEING UPGRADED TO A HURRICANE. SUMMARY OF 1120 AM CDT...1620 UTC...INFORMATION ----------------------------------------------- LOCATION...28.1N 88.6W ABOUT 75 MI...115 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER ABOUT 160 MI...250 KM SE OF NEW ORLEANS LOUISIANA MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H PRESENT MOVEMENT...NW OR 310 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...975 MB...28.79 INCHES $$ FORECASTER STEWART/BEVEN Link to comment Share on other sites More sharing options...
David Reimer Posted August 28, 2012 Share Posted August 28, 2012 Product: Air Force Vortex Message (URNT12 KNHC) Transmitted: 28th day of the month at 16:00Z Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306) Storm Number & Year: 09L in 2012 Storm Name: Isaac (flight in the North Atlantic basin) Mission Number: 31 Observation Number: 15 A. Time of Center Fix: 28th day of the month at 15:34:30Z B. Center Fix Coordinates: 28°07'N 88°30'W (28.1167N 88.5W) B. Center Fix Location: 159 miles (256 km) to the SE (144°) from New Orleans, LA, USA. C. Minimum Height at Standard Level: 1,217m (3,993ft) at 850mb D. Estimated (by SFMR or visually) Maximum Surface Wind: 55kts (~ 63.3mph) E. Location of the Estimated Maximum Surface Wind: 24 nautical miles (28 statute miles) to the W (261°) of center fix F. Maximum Flight Level Wind Inbound: From 347° at 59kts (From the NNW at ~ 67.9mph) G. Location of Maximum Flight Level Wind Inbound: 50 nautical miles (58 statute miles) to the W (265°) of center fix H. Minimum Sea Level Pressure: 975mb (28.79 inHg) I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 18°C (64°F) at a pressure alt. of 1,527m (5,010ft) J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,519m (4,984ft) K. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°F) K. Sea Surface Temp (collected at same location as temp inside eye): Not Available L. Eye Character: Not Available M. Eye Shape: Not Available N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature N. Fix Level: 850mb O. Navigation Fix Accuracy: 0.02 nautical miles O. Meteorological Accuracy: 2 nautical miles Remarks Section: Maximum Flight Level Wind: 94kts (~ 108.2mph) in the east quadrant at 15:50:00Z Link to comment Share on other sites More sharing options...
BeauDodson Posted August 28, 2012 Share Posted August 28, 2012 In case anyone missed it - Direct TV is broadcasting (rebroadcasting) live local television stations from New Orleans - from what people are saying (and what I am seeing here) it is on their INFO channels. Link to comment Share on other sites More sharing options...
valkhorn Posted August 28, 2012 Share Posted August 28, 2012 Judging by recon, there is quite a large area of tropical storm force winds with Isaac. People might be shocked to see how much wind they get from a minimal hurricane. Link to comment Share on other sites More sharing options...
QVectorman Posted August 28, 2012 Share Posted August 28, 2012 12Z UKMET has Isaac stationary, just offshore, from 0Z tonight to 12Z tomorrow morning. It has been one of the best performing models in terms of tracks so far. But it's not really stationary it jogs it parallel to the delta. Link to comment Share on other sites More sharing options...
Max Posted August 28, 2012 Share Posted August 28, 2012 The 13z HRRR looks to develop three separate mesovorticies with Isaac. I don't know if the HRRR tends to do that, but I would assume that Isaac having those mesovorticies in the eye wouldn't be a good thing. http://goo.gl/etEcy Link to comment Share on other sites More sharing options...
turtlehurricane Posted August 28, 2012 Share Posted August 28, 2012 First hurricane force wind gust at the tip of the Mississippi delta, pressure down to 993 mb. Link to comment Share on other sites More sharing options...
jparrott Posted August 28, 2012 Share Posted August 28, 2012 In case anyone missed it - Direct TV is broadcasting (rebroadcasting) live local television stations from New Orleans - from what people are saying (and what I am seeing here) it is on their INFO channels. Channels 325 and 349. They are rotating between NOLA and Mobile stations, changing channels when a station goes to a break. Link to comment Share on other sites More sharing options...
BeauDodson Posted August 28, 2012 Share Posted August 28, 2012 Starting to see more flooding reports Ocean Springs [Jackson Co, MS] public storm surge at 11:15 AM CDT -- member of the public reported water covering high school parking lot in ocean springs about one half mile inland. it was relayed to NWS New Orleans that it was south of the ocean springs airport. Pascagoula [Jackson Co, MS] emergency mngr reports storm surge at 11:15 AM CDT -- multiple streets in Pascagoula closed due to inundation from storm surge associated with hurricane Isaac. Local Storm Report by NWS LIX: Ocean Springs [Jackson Co, MS] emergency mngr storm report 11:15 AM CDT -- multiple streets in ocean springs closed due to inundation from storm surge associated with hurricane Isaac. Are we doing storm report chatter in this thread or elsewhere? Link to comment Share on other sites More sharing options...
am19psu Posted August 28, 2012 Share Posted August 28, 2012 Starting to see more flooding reports Ocean Springs [Jackson Co, MS] public storm surge at 11:15 AM CDT -- member of the public reported water covering high school parking lot in ocean springs about one half mile inland. it was relayed to NWS New Orleans that it was south of the ocean springs airport. Pascagoula [Jackson Co, MS] emergency mngr reports storm surge at 11:15 AM CDT -- multiple streets in Pascagoula closed due to inundation from storm surge associated with hurricane Isaac. Local Storm Report by NWS LIX: Ocean Springs [Jackson Co, MS] emergency mngr storm report 11:15 AM CDT -- multiple streets in ocean springs closed due to inundation from storm surge associated with hurricane Isaac. Are we doing storm report chatter in this thread or elsewhere? Let's keep this one on forecasting and start a new one for storm reports. Link to comment Share on other sites More sharing options...
am19psu Posted August 28, 2012 Share Posted August 28, 2012 Just so we're clear, observations that give hints about the forecast (e.g. satellite, radar, recon) go here. Observations about ground conditions, rainfall amounts, surge reports, levee breaks, etc go in the other thread. Link to comment Share on other sites More sharing options...
Cory Posted August 28, 2012 Share Posted August 28, 2012 The 13z HRRR looks to develop three separate mesovorticies with Isaac. I don't know if the HRRR tends to do that, but I would assume that Isaac having those mesovorticies in the eye wouldn't be a good thing. http://goo.gl/etEcy High-res models like HRRR can capture vorticity oscillations in the eyewall and form mesovortices. High-res (1km) WRF simulations that I've done will commonly form triangular and wavy eyewalls and mesovortices with no apparent negative impact on storm strength or structure. Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted August 28, 2012 Share Posted August 28, 2012 So this will spin like this moving slowly for many hours to come, wow http://www.votingrulez.com/file/uploads/SAT_GULH_VIS_ANI3.gif Link to comment Share on other sites More sharing options...
phil882 Posted August 28, 2012 Share Posted August 28, 2012 The 13z HRRR looks to develop three separate mesovorticies with Isaac. I don't know if the HRRR tends to do that, but I would assume that Isaac having those mesovorticies in the eye wouldn't be a good thing. http://goo.gl/etEcy Mesovorticies are very common within eyewalls of TCs. You don't typically see it in modeling because they don't have the resolution to properly resolve these features. The HRRR on the other hand does not have this problem. If the HRRR is correct in its forecast (a big if), that would suggests an intensifying storm with a tightening eyewall. Link to comment Share on other sites More sharing options...
Dunkman Posted August 28, 2012 Share Posted August 28, 2012 Mesovorticies are very common within eyewalls of TCs. You don't typically see it in modeling because they don't have the resolution to properly resolve these features. The HRRR on the other hand does not have this problem. If the HRRR is correct in its forecast (a big if), that would suggests an intensifying storm with a tightening eyewall. Looking at the last hour of frames out of KLIX it certainly appears that it is trying to tighten the eyewall around the west side. However, looking at the size of the circulation and the distance away from the center that the eastern band with max winds is located, it would be very difficult for Isaac to do. Link to comment Share on other sites More sharing options...
NaoPos Posted August 28, 2012 Share Posted August 28, 2012 Speaking of multiple vortices, Could we be seing one in the mid levels (left of the clearing eye wall?) or is this just the mid level center decoupled from the llc? Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 28, 2012 Share Posted August 28, 2012 Speaking of multiple vortices, Could we be seing one in the mid levels (left of the clearing eye wall?) or is this just the mid level center decoupled from the llc? Any chance you could post the exact link to this? Thanks. Link to comment Share on other sites More sharing options...
NaoPos Posted August 28, 2012 Share Posted August 28, 2012 Any chance you could post the exact link to this? Thanks. http://tropic.ssec.wisc.edu/real-time/storm.php?&basin=atlantic&sname=09L&invest=NO&zoom=4&img=1&vars=11111000000000000000000&loop=0 From there, you have to choose vis1 km. Link to comment Share on other sites More sharing options...
Uncle Bobby Posted August 28, 2012 Share Posted August 28, 2012 Here is the first radar image with a little tiny bit of Louisiana real estate sort of inside the eye! Link to comment Share on other sites More sharing options...
Yeoman Posted August 28, 2012 Share Posted August 28, 2012 Here is the first radar image with a little tiny bit of Louisiana real estate sort of inside the eye! wow - a 100+ mile diameter eye? Link to comment Share on other sites More sharing options...
BeauDodson Posted August 28, 2012 Share Posted August 28, 2012 Seems like the HRRR didn't do a terrible job overnight - wasn't perfect by any means - but seemed to be on the right track. Not sure how I would grade its performance overall - but has been interesting to follow it since it updates every hour. Link to comment Share on other sites More sharing options...
Uncle Bobby Posted August 28, 2012 Share Posted August 28, 2012 wow - a 100+ mile diameter eye? Pretty close. I measured the widest dimension, from WSW to ENE, and it is 84nm there. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.