phil882 Posted July 3, 2014 Share Posted July 3, 2014 I still wouldn't be surprised to see a quick bout of intensification the next 24 hours. Shear is still low and as mentioned earlier today, SSTs are warm all the way to the latitude of the outer banks in NC. It's just a matter of Arthur mixing out this last bit of dry air in its inner core. As the storm starts to move with an eastward component, that will also eliminate the remaining nagging weak westerly shear thats been affecting the system intermittently today (you can see the arc clouds reminiscent of dry air on its western flank). The IR presentation still doesn't look amazing, but the small size of inner core still bodes well for intensification since we are still 24-30 hours from the potential impact. Alex (2004) is actually a pretty good analog (although Arthur may be slightly west of Alex's track). I think the rate of intensification will also be similar, since Alex intensified to around 85 knots from a strong TS in roughly the same position that Arthur is as well. Link to comment Share on other sites More sharing options...
Floydbuster Posted July 3, 2014 Share Posted July 3, 2014 I still wouldn't be surprised to see a quick bout of intensification the next 24 hours. Shear is still low and as mentioned earlier today, SSTs are warm all the way to the latitude of the outer banks in NC. It's just a matter of Arthur mixing out this last bit of dry air in its inner core. As the storm starts to move with an eastward component, that will also eliminate the remaining nagging westerly shear thats been affecting the system intermittently today (you can see the arc clouds reminiscent of dry air on its western flank). The IR presentation still doesn't look amazing, but the small size of inner core still bodes well for intensification since we are still 24-30 hours from the potential impact and plenty of time to mix out the last of the dry air. I was thinking the same thing, Phil. I'd like for Arthur to look a little better on the infrared satellite along with the visible and radar. Nonetheless, obviously the system is right on the edge of hurricane strength and gusts are certainly likely over 85 mph in the strongest semi-circle of the storm. Link to comment Share on other sites More sharing options...
calamity Posted July 3, 2014 Share Posted July 3, 2014 Another full day of Arthur. It looks like there has been some westerly wind shear. Amazing structual change, though. Link to comment Share on other sites More sharing options...
Jackstraw Posted July 3, 2014 Share Posted July 3, 2014 It will be interesting to watch over the next 12-24 hours. there are a lot of "minor" cast members in Arthur's little drama. A weak mid level ridge a few hundred miles north of him, the big TUTT impending down on the sub tropical ridge to his East. The trough coming East across the central US attm is a little slower than forecast. He's in a fairly weak steering flow and will probably get bounced around some before he gets sucked up. Weak storms can do funky things when there's some mid level dynamics going on. I'm by no means wishcasting, I think the forecast track is pretty spot on, but it wouldn't surprise me if there were some unexpected movements East or West, or maybe even forward speed slowing down over the next 24 hours. It's just gonna be the usual, where he'll be when it does pick him up. http://www.ssd.noaa.gov/goes/east/eaus/flash-wv.html Link to comment Share on other sites More sharing options...
DMADKAT Posted July 3, 2014 Share Posted July 3, 2014 No. What I was saying was, that I don't recall any storm to strike the U.S. coast with any validity on Independence Day. For those on the Outer Banks, it could be a great storm for a July 4th'er . Their fragile beach has taken a licking here lately with each passing storm, whether it be a Kane or a Nor-easter. Link to comment Share on other sites More sharing options...
phil882 Posted July 3, 2014 Share Posted July 3, 2014 Another full day of Arthur. It looks like there has been some westerly wind shear. Amazing structual change, though. Great loop as always... you can sort of see how the convective towers aren't making it all the way around the center (sure the cirrus shield is, but not the deeper convection you want to see wrap around the core). Link to comment Share on other sites More sharing options...
phil882 Posted July 3, 2014 Share Posted July 3, 2014 The radar presentation has degraded some this evening, but its still moving west of due north, and each little left wobble like this is concerning for those in the outer banks right now. Once the storm does start moving with an eastward component of motion, the westerly shear vector will decrease and we should finally see the storm shake off the remainder of the dry air near the inner core. Link to comment Share on other sites More sharing options...
Jackstraw Posted July 3, 2014 Share Posted July 3, 2014 Great loop as always... you can sort of see how the convective towers aren't making it all the way around the center (sure the cirrus shield is, but not the deeper convection you want to see wrap around the core). That's a good point, probably due to the mid level dry air intrusion. Dr. Lyons used to say the storm would take on a "screaming eagle" look to it when that happened lol. It seems his ventilating ridge is still displaced to the S-SSE also. One good thing in it's favor is because of the geography of the land moving farther away, the storms feeding in from the SE should now be over open water longer transporting more moisture into the surrounding environment. Not a lot of time to do so but there is some time. Link to comment Share on other sites More sharing options...
phil882 Posted July 3, 2014 Share Posted July 3, 2014 That's a good point, probably due to the mid level dry air intrusion. Dr. Lyons used to say the storm would take on a "screaming eagle" look to it when that happened lol. It seems his ventilating ridge is still displaced to the S-SSE also. One good thing in it's favor is because of the geography of the land moving farther away, the storms feeding in from the SE should now be over open water longer transporting more moisture into the surrounding environment. Not a lot of time to do so but there is some time. The thing with dry air intrusion is that you need something (shear) to advect the dry air into the core. If there was literally no shear over the TC, the system would eventually axis-symmetrize and mix out all the dry air. So the light westerly shear that was observed today prevented that from happening. The storm still intensified, but probably not as much (or as quickly) as it could have had if that westerly shear not been there. Lets compare Arthur to a similar small TC that was also under the influence of dry air in its vicinity. Cristina this year in the EPAC is actually a pretty good example of what can happen when there is plenty of dry air surrounding a storm, but the shear decreases to nearly zero. What happens is all the convection becomes focused in the inner core and since there is nothing advecting the dry air in. The storm (as you can see in the visible animation below) was able to rotate deep convective activity around its inner core. The storm underwent RI shortly after this animation from a Cat 1 to a Cat 4 in less than 12 hours. Link to comment Share on other sites More sharing options...
Jackstraw Posted July 3, 2014 Share Posted July 3, 2014 The thing with dry air intrusion is that you need something (shear) to advect the dry air into the core. If there was literally no shear over the TC, the system would eventually axis-symmetrize and mix out all the dry air. So the light westerly shear that was observed today prevented that from happening. The storm still intensified, but probably not as much (or as quickly) as it could have had if that westerly shear not been there. Lets compare Arthur to a similar small TC that was also under the influence of dry air in its vicinity. Cristina this year in the EPAC is actually a pretty good example of what can happen when there is plenty of dry air surrounding a storm, but the shear decreases to nearly zero. What happens is all the convection becomes focused in the inner core and since there is nothing advecting the dry air in. The storm (as you can see in the visible animation below) was able to rotate deep convective activity around its inner core. The storm underwent RI shortly after this animation from a Cat 1 to a Cat 4 in less than 12 hours. Thank you that makes sense. I've seen storms surrounded by SAL in the Atlantic yet they sustain or intensify in a 0 to very low shear environment contrary to what one might expect. Also, I don't know how to post graphics here, but the latest runs of the HRRR and RAP are interesting, at least in the way they are handling the trough moving towards the East coast. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 Pretty good convection on the southeast/east eyewall now. Lets see if that can wrap around over the next few hours. EDIT: Here's an IR image showing the blowup of convection on the eastern eyewall. Also of note is the increasing velocities on the MLB radar. It's right out at the range of the radar (which means we're not talking about a steady increase in elevation for wind readings. Since its right out at the range we're talking a steady altitude of about 24,000 feet. That's quite high but velocities have increased about 10 knots over the past hour of radar data.) Link to comment Share on other sites More sharing options...
Sophisticated Skeptic Posted July 3, 2014 Share Posted July 3, 2014 0z GFS continues the westward trend. NYC could be in line for tropical storm force winds...if this keeps up. Link to comment Share on other sites More sharing options...
Dunkman Posted July 3, 2014 Share Posted July 3, 2014 0z GFS continues the westward trend. NYC could be in line for tropical storm force winds...if this keeps up. It's east from 18z unless my brain is completely fried...which is entirely possible. Hottest day in 2 years here today. Link to comment Share on other sites More sharing options...
Hurr_Tracker13 Posted July 3, 2014 Share Posted July 3, 2014 00z is east from 18z. Link to comment Share on other sites More sharing options...
gulfcane Posted July 3, 2014 Share Posted July 3, 2014 Boom! Link to comment Share on other sites More sharing options...
phil882 Posted July 3, 2014 Share Posted July 3, 2014 00z is east from 18z. Yep... looking at a d(prog)/dt assessment of the GFS forecast at landfall (now around 30 hours out) it doesn't really have a pronounced trend east/west, although it certainly has trended faster with the motion of Arthur. http://www.tropicaltidbits.com/analysis/models/gfs/2014070300/gfs_z850_vort_seus_comp30.html Link to comment Share on other sites More sharing options...
Blizz Posted July 3, 2014 Share Posted July 3, 2014 Arthur looks really good on IR... but really bad on radar, especially on its west side. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 Arthur looks really good on IR... but really bad on radar, especially on its west side. I wouldn't say it looks terrible considering how far it is from the radar. Personally I think it looks a bit better than it did about two hours ago with new convection firing on the north side. Although that's subjective to what the recon aircraft finds when it arrives in a couple of hours. Link to comment Share on other sites More sharing options...
phil882 Posted July 3, 2014 Share Posted July 3, 2014 Arthur looks really good on IR... but really bad on radar, especially on its west side. The IR shows the blow up of convection on the TCs northeast side... its possible Arthur is still intensifying given the intensity of the convection within the eyewall. It would be nice to see it close up the W side of the eye, although as long as the shear is sticking around it will be hard. The HRRR suggests that outflow will finally develop west of Arthur tonight and tomorrow, in response to the end of the annoying westerly shear that has been advecting dry air into its core. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 Convection has done a rather good job IMO of wrapping around the northern semicircle over the past hour. Looks like one or two hot towers based off this IR image. That should at least keep the pressure steady if not slightly falling compared to the earlier 988MB report. Perhaps this convective burst will cause an increase in winds relative to the pressure. Link to comment Share on other sites More sharing options...
downeastnc Posted July 3, 2014 Share Posted July 3, 2014 Going to be a long night for the coastal areas of NC tomorrow night, I was just looking at the bouys and buoy 41013 ( Frying Pan shoals) is offline and Arthur should pretty much go right over it tomorrow night is a shame we wont have that data. Link to comment Share on other sites More sharing options...
Sophisticated Skeptic Posted July 3, 2014 Share Posted July 3, 2014 00z is east from 18z. Just a smidgen. I was regarding the overall westward trend from the last 24 hours or so = maintained. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 AF303 (Mission 9) out of Biloxi is airborne and enroute to Arthur. Pretty nice night flight across the Gulf Coast I'm sure. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 UW - CIMSSADVANCED DVORAK TECHNIQUEADT-Version 8.2.1Tropical Cyclone Intensity Algorithm----- Current Analysis -----Date : 03 JUL 2014 Time : 034500 UTCLat : 30:20:39 N Lon : 79:15:39 WCI# /Pressure/ Vmax4.6 / 974.4mb/ 79.6ktFinal T# Adj T# Raw T#4.6 4.6 3.2Center Temp : -54.1C Cloud Region Temp : -55.7CScene Type : UNIFORM CDO CLOUD REGION w/ MW EYEPositioning Method : SPIRAL ANALYSISOcean Basin : ATLANTICDvorak CI > MSLP Conversion Used : ATLANTICTno/CI Rules : Constraint Limits : MW ONWeakening Flag : OFFRapid Dissipation Flag : OFF Link to comment Share on other sites More sharing options...
wxmeddler Posted July 3, 2014 Share Posted July 3, 2014 00z HWRF has landfall in Beaufort at 982mb, just barely over 64kts on the OBX. Dry air clears out of the circulation by 18z tomorrow. Link to comment Share on other sites More sharing options...
BuffaloWeather Posted July 3, 2014 Share Posted July 3, 2014 That eye is really trying to get its act together. Link to comment Share on other sites More sharing options...
wxmeddler Posted July 3, 2014 Share Posted July 3, 2014 WFO MHX going balsy: Link to comment Share on other sites More sharing options...
OHweather Posted July 3, 2014 Share Posted July 3, 2014 There are some 30k foot tops in the western "eyewall" showing up on the KJAX radar, so it may be slowly trying to close off the eyewall. Link to comment Share on other sites More sharing options...
David Reimer Posted July 3, 2014 Share Posted July 3, 2014 Impressive expansion of convection compared to earlier this evening. Link to comment Share on other sites More sharing options...
Sophisticated Skeptic Posted July 3, 2014 Share Posted July 3, 2014 One of the latest images too. I see a face / eyes / body / feet . and wings ? Too much wine today, but the image is worth checking out. Link to comment Share on other sites More sharing options...
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