Hurricane Hermine Discussion Part 2

Gusts up to 59mph on Nantucket and nearby areas:
http://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=LSR

Radz wrote:Lee's take on Hermine: https://www.facebook.com/leegoldbergABC7/videos/vb.311624215690792/549151115271433/?type=2&theater¬if_t=live_video¬if_id=1473121948671332

was just going to post this video..just watch...interesting...

62kt reported out on eastern LI.
Moving after than modelled west.
It will weaken but this storm is being tugged back by the trough over WV and semicircle back on the se side of the trough.
This is what is pulling this back and may bring it closer to rhe coast that initially thought, amazing isn't it.
RGEM lead the way since Saturday if I recall.
Jersey shore sees another abnormal high tide and windy conditions, maybe some showers tomorrows, banding.

Mugs Lee Goldberg talked about how storm coming back.

Good luck if you start school tom

Mugs...Oops I guess my timing is off tonight just saw your post right before mine..have a good night...I hope we are tracking snow sooner rather than later

weatherwatchermom wrote:Mugs...Oops I guess my timing is off tonight just saw your post right before mine..have a good night...I hope we are tracking snow sooner rather than later

No problem mom. Me too .....SNOW. Good luck with school.

Radz wrote:Lee's take on Hermine: https://www.facebook.com/leegoldbergABC7/videos/vb.311624215690792/549151115271433/?type=2&theater¬if_t=live_video¬if_id=1473121948671332

good vid by Lee. Sums it up.

Winds picking up significantly

Hey Scott, yeah, I definitely think that's a reason, and probably THE reason. Newton's law of physics: An object in motion will remain in motion unless acted upon by an outside force. In this case, the outside force was too late (the trough catching it and phasing in with it). The trick is figuring out WHY that was the reason. Sure we could present arguments for the block to the east not being as strong as modeled, and I'm sure that had something to do with it. But I think there are two other parts to it, as well. The first is that I think the original trough was able to impart enough of a westerly component to its forward motion such that it allowed it to speed up, even after the trough was out of the picture. How? Because by the time the trough departed, Hermine was already embedded in the mid-latititude southwesterly flow, which was partially aided by the trough split (you can go back and see how there was still one H5 contour to the south of the system which shows it was still being steered by that flow until the energy finally caught up to it).

The second, and it's still a hypothesis on my end since I haven't actually looked at it, and it's one that I had from the time the GFS first showed this type of solution, is the direction of the PV gradient. PV, or potential vorticity, is kind of a hard concept to explain, but basically it's similar to "regular" vorticity; the energy we look at at H5. However, it's more of a measure of spin (vorticity) acting "in the background" of H5, and isn't necessarily depicted on the regular H5 maps we look at. PV is a measure, a quantitative description, of how much spin exists in the atmosphere just as a result of the curvature of the Earth in relation to the Earth's rotation; Coriolis. We all know that the Coriolis effect increases as you head toward the Poles. And we know that it's one of the reasons that tropical systems tend to recurve as they enter latitudes above 10 degrees N/S. Another way to describe that process is PV. If you've ever heard of beta drift in tropical systems, it's an explanation of why the systems recurve. Storms that originate in the tropics, essentially originate in areas of very low PV because the Coriolis effect is essentially negligible. However, as the system grows in size and organizes its own rotation in relation the Earth's, it actually experiences small differences in PV from its south side to its north side. The gradient of PV, as with anything, is always directed from low to high. So, using this as a vector, it would slowly exert a weak northward-directed force on the system because higher PV exists on the north side of the system.

Now, expanding this idea, troughs that originate in the mid-latitudes have much higher PV than even the north side of a tropical system. My hypothesis is that once Hermine was influenced by the first trough and became weakly embedded in the southwesterly flow on its eastern side, I think it might have also felt an additional force directed northeastward towards that trough even though it was departing, because of the added influence of the PV gradient. Then, once that trough moved too far, and even though the secondary H5 energy was not completely consolidated to the west, and H5 wasn't closed off yet, I think that because that trough also had a higher PV than Hermine, it allowed it to start slowing down before closing off because of what was then a westward-directed PV gradient.

I think that could be one of the underlying issues with why the models had such a tough time with modeling how far east it would make it, because they underrepresented the strength of the PV gradient associated with the departing trough to the northeast before the secondary energy could start to have a similar effect. Then, once H5 did close off, I think it was just a matter of how intensely and where that was determining the westward extent it could manage to get to based off of those dynamics. Again, I don't know, but that's my thinking, and was my thinking when I first saw this type of solution.

I have to say that was incredibly ridiculous to do on mobile ahaha secondly, I give Lee props for that video. I think he handled that very well and gave a great high-order look at what happened, or didn't happen lol

Interesting

http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/025619.shtml?radii#contents

0z JMA

Just woke back up after sleeping like a day after working overnights straight and tracking this PITA lol. It's cloudy, but oddly, dead still, no wind, less than when the low made its first inital pass much farther away but stronger, looked at the meso analysis and the storm did indeed tuck in back west to the south of LI at the moment but its lost all its steam, not much moisture and 1005 or 1004 low at the lowest. May continue to drift west and peter out to nothing over NJ, or do similar but follow the NJ coast south to the Delmarva, or it could turn back east and dissipate as it heads towards MA. Place bets! (And havent seen/care about any model solns right now, they have been terrible)

Perhaps I can solve my own question. When it was over land it transitioned to extratropical so the wind field vastly spread out, that may be why a few days ago it was cloudy and windy, yet the other day when it was back over water, sunny and nothing. It may have tried to redevelop a weak warm core and tighten up its wind field (which is why LI is mostly the only people feeling it right now)

The cone is just a circle now. Centered south of LI. Basically a circle over the NY Bight and and southern CT. For what its worth winds are around 20 mph now

jmanley32 wrote:

Dtone wrote:The cone is just a circle now. Centered south of LI. Basically a circle over the NY Bight and and southern CT.  For what its worth winds are around 20 mph now

I know its hilarious, NHC basically saying they have no clue where its going, their best bet is the line of circles but that keeps pushing west every full advisory, I think winds will increase and peak today around here and then die off into tomorrow, 8am pressure is down 1 mb to 996, still holding its own at 65moph storm.  She is really trying hard, its pretty crazy cuz she was supposed to have been weakened to 50mph storm by now, I did note windfield did shrink a little.

yeah lol. Guess it'll slowly die out just offshore.
Winds gusting to 40 at JFK.

Upped it again

New NHC cone

The hurricane models busted way too strong even to the bitter end, Hermine is no 990s low near LI and its not going near Jersey that stregnth, it'll remain a weak 1000-1010mb low and probably dissipate. It's now shifting between cloudy and mostly cloudy and getting a little breezy.