lman Posted August 27, 2011 Share Posted August 27, 2011 Another disco from Mount Holly/Philly about jet dynamics keeping Irene from weakening as much as cooler waters and land interaction would disctate. Props to the guys at Mount Holly for being on top of these dynamics! I believe they got a shout out the other day from TWC. Link to comment Share on other sites More sharing options...
thegreatdr Posted August 27, 2011 Share Posted August 27, 2011 That's a sign of extratropical transition. Since it's in the right entrance region of a jet, it should be expected. But as long as it maintains central convection, the storm shouldn't cross height or thickness lines. I guess in a diffluent flow regime, Hurricanes move 45 degrees to the left of the flow. Hence they are getting absorbed into the jet stream as the move along it. This may explain why a new height contour appers south of Irene every 6 hours. Link to comment Share on other sites More sharing options...
boulderrr Posted August 27, 2011 Share Posted August 27, 2011 New NHC advisory out: Maintained wind speed at 85 mph Pressure still around 952 mb Shifted their forecast slightly toward the west. Link to comment Share on other sites More sharing options...
Isopycnic Posted August 27, 2011 Share Posted August 27, 2011 Bill Read and his "Shaft of Destruction" Link to comment Share on other sites More sharing options...
usedtobe Posted August 27, 2011 Share Posted August 27, 2011 That's a sign of extratropical transition. Since it's in the right entrance region of a jet, it should be expected. But as long as it maintains central convection, the storm shouldn't cross height or thickness lines. That interaction is also why this storm could rival Floyd in places in terms of inland flooding. Link to comment Share on other sites More sharing options...
Rainshadow Posted August 27, 2011 Share Posted August 27, 2011 That interaction is also why this storm could rival Floyd in places in terms of inland flooding. Antecedent conditions in our area are wetter than they were before Floyd, a comparable rain amount within the same period of time is going to make the flooding even worse if that's possible. Link to comment Share on other sites More sharing options...
SN_Lover Posted August 27, 2011 Share Posted August 27, 2011 Well it looks like if Irene goes over open waters again, it has the risk of becoming baroclinic. And the weakening process could be retarded by this developing jet streak. Link to comment Share on other sites More sharing options...
usedtobe Posted August 27, 2011 Share Posted August 27, 2011 Antecedent conditions in our area are wetter than they were before Floyd, a comparable rain amount within the same period of time is going to make the flooding even worse if that's possible. True! it probably will top floyd in terms of flooding and probably poweer outages due to trees coming down. Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 27, 2011 Share Posted August 27, 2011 Another disco from Mount Holly/Philly about jet dynamics keeping Irene from weakening as much as cooler waters and land interaction would disctate. MUCH OF THE MODEL GUIDANCE STILL SHOWS THE DEVELOPMENT OF A STRONG250 MB JET NORTH OF THE HURRICANE INTO SUNDAY, GENERALLY FROM THE EASTERN GREAT LAKES TO NORTHERN NEW ENGLAND. THIS UPPER-LEVEL JET EVEN HAS SOME ANTICYCLONIC CURVATURE TO IT AND GIVEN THE ORIENTATION OF THIS JET IT IS SUCH THAT IRENE IS WITHIN THE RIGHT ENTRANCE REGION AS SHE TRACKS NORTHWARD. THIS SCENARIO MAY TEND TO HELP WITH A POLEWARD UPPER-LEVEL OUTFLOW CHANNEL AND ASSIST IN THE INTENSITY OF THE SYSTEM AS A WHOLE. THEREFORE, DESPITE SOME INCREASING SHEAR AS THE HURRICANE GAINES LATITUDE ALONG WITH COOLER WATERS AND LAND INTERACTIONS, PERHAPS THIS IS WHY MUCH OF THE MODEL GUIDANCE NEARLY INSISTS THIS SYSTEM MAINTAINS A RATHER LOW CENTRAL PRESSURE ALL THE WAY INTO SOUTHERN NEW ENGLAND. Just saw elsewhere this may have been one of our own red taggers who has been on top of the jet interaction... Link to comment Share on other sites More sharing options...
SN_Lover Posted August 27, 2011 Share Posted August 27, 2011 The updated 12UTC NAM now shows the jet streak is slow to develop. looks like the phasing of the two jet streaks that the GFS indicated yesterday will not happen according to the NAM. And the jet streak will likely develop when Irene is over land or right before landfall. Link to comment Share on other sites More sharing options...
Dunkman Posted August 27, 2011 Share Posted August 27, 2011 A couple things to note...12z Euro keeps the same theme, brushes up to Atlantic City then goes right over NYC. Also, for those of you up north, the Euro especially and the GFS sometimes a run or 2 later absolutely nailed the NC landfall, not just the location, but even the nuances of the track including the east movement during the day evening yesterday and the turn to the north and even a bit west of north overnight in order to make the Cape Lookout landfall. So far the track across NC on the Euro through about 9h looks perfect as well...I really don't see any reason to think it doesn't have the track almost exactly right, it seems to have a perfect handle on this storm track wise. Link to comment Share on other sites More sharing options...
Derecho! Posted August 27, 2011 Share Posted August 27, 2011 A couple things to note...12z Euro keeps the same theme, brushes up to Atlantic City then goes right over NYC.. Also of note is that this is the first time most of the GFS ensemble members are WEST or over NYC. Link to comment Share on other sites More sharing options...
A-L-E-X Posted August 27, 2011 Share Posted August 27, 2011 946.8mb pressure reading latest recon. Link to comment Share on other sites More sharing options...
phil882 Posted August 27, 2011 Share Posted August 27, 2011 http://philstropicalweatherblog.wordpress.com/2011/08/27/irene-makes-first-landfall-near-cape-lookout-at-85-mph-marching-towards-the-northeast/ My updated thoughts this evening... looks like major impacts are still on tap further northeast, even if this storm does weaken below hurricane intensity. Track from yesterday right on track Link to comment Share on other sites More sharing options...
phil882 Posted August 28, 2011 Share Posted August 28, 2011 Seems like my track outlined above is going to be way to slow, but I nailed the landfall track (only off by .1 degree N and .0 degrees W) and was only 5 knots off on intensity. This wouldn't be so impressive, if it weren't for the fast that I've had practically had the same forecast since Tuesday. Observe the 120 hour forecast point below. I think its worth mentioning that the ECWMF did an excellent job and if it were not for its consistency, I don't think my forecast would have been as good. Link to comment Share on other sites More sharing options...
bluewave Posted August 29, 2011 Share Posted August 29, 2011 Very nice Job. Link to comment Share on other sites More sharing options...
ag3 Posted August 29, 2011 Share Posted August 29, 2011 Very nice Job. A little too far east. Euro NAILED the track. Link to comment Share on other sites More sharing options...
bluewave Posted August 29, 2011 Share Posted August 29, 2011 A little too far east. Euro NAILED the track. The Euro did very well once it started to track Irene closer to the coastline. But the EnKF GFS Was correct when the OP GFS was going east of MTP. Link to comment Share on other sites More sharing options...
GaWx Posted August 29, 2011 Share Posted August 29, 2011 The Euro did quite well with track. However, it was quite a bit too strong with the lowest pressures within the 30-38N corridor. The lowest Euro pressures for Irene were above 30N, where it has been biased too strong since last season. For Irene above 30N, it had the following as the lowest for the 8/22 12Z through 8/26 0Z runs (in mb), respectively: 926, 936, 923, 927, 925, 921, 924, and 918. The lowest for 30N or higher verified to be 945 mb. So, adding about 20 mb to the Euro when it is very strong and way out of line with the other globals above 30N may be a reasonable thing to do. That would have worked pretty well last season as well as with Irene. Link to comment Share on other sites More sharing options...
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