ATL: NATE - Post Tropical - Discussion

[storm_in_a_teacup]

WV showing the PV ring effect of what I call secondary ventilation.
Same pattern like Harvey.
Think of it as Nate creating an updraft in the heavy convection.
The air flows out in the upper troposphere and then sinks back to the surface in the subsidence of the PV anomaly.
That surface air then flows back into Nate with moisture being added due to surface heat exchange with the hot water.

Here is the WV image and the corresponding 355K PV.
Note where the orange PV anomaly ring is and compare to the dry air on WV.

Bottom line, this is becoming well ventilated even though there may not be an associated ULL nearby to create an outflow channel.

It's crazy how large the influence of the storm is. I didn't know Harvey did this thing too. Was Harvey always doing that, or only when first forming?
(Also...what does PV stand for?...)

[Chris_in_Tampa]

Air Force (around 845mb) through 8:02pm EDT.
NOAA (around 700mb) through 8:02pm EDT.

[CrazyC83]

URNT15 KNHC 070112
AF307 0716A NATE HDOB 30 20171007
010230 2130N 08554W 8429 01437 9925 +193 +191 211004 007 011 004 05
010300 2130N 08554W 8429 01437 9928 +195 +182 135002 003 013 001 03
010330 2133N 08557W 8428 01440 9927 +199 +174 102004 004 016 001 03
010400 2134N 08558W 8430 01443 9933 +197 +176 100004 005 011 002 03
010430 2134N 08559W 8425 01450 9938 +193 +181 058002 005 /// /// 03
010500 2132N 08559W 8426 01444 9937 +191 +183 247004 006 009 003 00
010530 2131N 08558W 8431 01436 9933 +193 +183 259007 007 011 003 03
010600 2130N 08557W 8429 01437 9931 +193 +188 267011 012 012 001 00
010630 2128N 08556W 8428 01441 9930 +199 +182 259020 023 012 001 03
010700 2127N 08555W 8433 01437 9930 +197 +190 259025 025 016 001 00
010730 2125N 08554W 8429 01442 9931 +200 +186 256027 028 018 001 03
010800 2124N 08553W 8428 01445 9934 +196 +191 258031 033 025 000 00
010830 2122N 08552W 8429 01444 9936 +197 +192 258034 034 023 002 00
010900 2121N 08551W 8430 01445 //// +195 //// 257038 039 037 003 05
010930 2120N 08550W 8422 01459 //// +176 //// 250039 041 /// /// 05
011000 2121N 08548W 8432 01451 //// +189 //// 246037 040 /// /// 05
011030 2123N 08549W 8433 01437 9932 +200 +198 248034 036 042 000 01
011100 2124N 08550W 8429 01443 9931 +199 +196 249031 033 025 002 03
011130 2125N 08551W 8430 01441 9929 +200 +192 247029 031 020 002 00
011200 2127N 08552W 8431 01439 9931 +198 +188 247026 028 020 002 00
$$
;

Center is quite broad.

[GCANE]

WV showing the PV ring effect of what I call secondary ventilation.
Same pattern like Harvey.
Think of it as Nate creating an updraft in the heavy convection.
The air flows out in the upper troposphere and then sinks back to the surface in the subsidence of the PV anomaly.
That surface air then flows back into Nate with moisture being added due to surface heat exchange with the hot water.

Here is the WV image and the corresponding 355K PV.
Note where the orange PV anomaly ring is and compare to the dry air on WV.

Bottom line, this is becoming well ventilated even though there may not be an associated ULL nearby to create an outflow channel.



It's crazy how large the influence of the storm is. I didn't know Harvey did this thing too. Was Harvey always doing that, or only when first forming?
(Also...what does PV stand for?...)

PV is Potential Vorticity.
At 355K it indicates Vorticity high up in the troposphere.
That kind of vorticity pushes air down to the surface.

[Aric Dunn]

Both these recent recon passes are showing the center possibly being pulled towards the convection to the south .. some sort of a cyclonic loop.. so far the center has been out running the convection if this is a re-orginization and convection finally wraps aorund then faster deepening is possible..

[NDG]

Look how elongated the circulation is... the noname system has been intereacting and pulling the inflow away from NATE.. once NAte gets north of the channel and the noname system drops more to the south and weakens NATE will be able to consolidate more. this stretching of the pressure field to the north is what is causing nate to accelerate in the direction of that pressure change. next 12 hours or that should slowly be less of a factor. right now though it is keeping nate not vertically stacked.

https://preview.ibb.co/hsUDLb/20171006_ ... W_85pc.jpg

Isn't the the remnants of your naked no name swirl approaching 93W?
What is to the NW of Nate was yet another vorticity that has been rotating around.

[Chris_in_Tampa]

NOAA (around 700mb) through 9:12pm EDT.

[Chris_in_Tampa]

Air Force (around 845mb) through 9:12pm EDT. Looping near center.

[Aric Dunn]

Look how elongated the circulation is... the noname system has been intereacting and pulling the inflow away from NATE.. once NAte gets north of the channel and the noname system drops more to the south and weakens NATE will be able to consolidate more. this stretching of the pressure field to the north is what is causing nate to accelerate in the direction of that pressure change. next 12 hours or that should slowly be less of a factor. right now though it is keeping nate not vertically stacked.

https://preview.ibb.co/hsUDLb/20171006_ ... W_85pc.jpg

Isn't the the remnants of your naked no name swirl approaching 93W?
What is to the NW of Nate was yet another vorticity that has been rotating around.

it is the same thing just really elongated out north to south since nate is stronger.

[GCANE]

Looks a few degrees to the east, what kind of implications will this have in the latter track?

Concern is a track over the Loop Current.

Also watching a High Theta-E Ridge to the NW.

[Dean4Storms]

The LLC positions just keep coming in east of the forecast track from Recon. At some point if this continues to reach the SE LA Coast Nate is going to have to turn a good bit NW.

[Aric Dunn]

looks like a partial eyewall finally trying to develop of the eastside. ... lets see if the llc out runs it again..

[Chris_in_Tampa]

Air Force (around 845mb) through 9:22pm EDT.
NOAA (around 700mb) through 9:22pm EDT.

[CrazyC83]

URNT15 KNHC 070122
AF307 0716A NATE HDOB 31 20171007
011230 2128N 08553W 8429 01441 9932 +195 +184 249022 025 015 002 00
011300 2129N 08554W 8429 01441 9932 +193 +190 246015 019 011 001 01
011330 2131N 08555W 8429 01439 9933 +195 +182 243011 012 015 002 00
011400 2132N 08556W 8429 01440 9931 +196 +177 240008 009 011 001 00
011430 2134N 08557W 8432 01436 9933 +195 +176 243004 006 014 002 00
011500 2135N 08558W 8426 01444 9934 +192 +183 197001 003 011 002 03
011530 2137N 08559W 8433 01436 9934 +193 +183 082001 002 010 003 03
011600 2138N 08600W 8430 01443 9934 +194 +181 094007 008 016 002 03
011630 2139N 08601W 8429 01443 9937 +191 +183 097010 011 012 002 03
011700 2140N 08602W 8434 01438 9938 +192 +185 094011 011 019 001 00
011730 2142N 08604W 8428 01448 9938 +196 +185 094012 012 019 000 00
011800 2143N 08605W 8429 01448 9941 +197 +184 090013 014 024 001 03
011830 2144N 08606W 8435 01443 9941 +196 +183 083013 013 024 001 03
011900 2145N 08608W 8432 01446 9945 +193 +176 077011 012 024 001 03
011930 2146N 08609W 8428 01454 9947 +192 +175 072012 012 024 000 00
012000 2148N 08610W 8428 01454 9951 +187 +182 072012 013 022 002 00
012030 2149N 08611W 8433 01452 //// +181 //// 074015 016 025 000 01
012100 2150N 08613W 8430 01455 9957 +183 +182 074017 018 025 000 01
012130 2151N 08614W 8429 01459 9961 +182 +177 072021 022 027 001 05
012200 2153N 08615W 8429 01463 9962 +182 +179 063027 029 029 001 05
$$
;

[NDG]

X is approximately where they closed off the circulation on the last pass.

[CrazyC83]

URNT15 KNHC 070132
AF307 0716A NATE HDOB 32 20171007
012230 2154N 08617W 8429 01465 9964 +185 +175 065029 030 028 001 01
012300 2155N 08618W 8432 01462 9965 +187 +174 065033 035 027 001 03
012330 2156N 08619W 8429 01468 9968 +188 +169 065038 039 025 002 00
012400 2157N 08621W 8431 01468 9975 +178 +173 069040 042 022 001 05
012430 2159N 08622W 8429 01472 //// +173 //// 067040 041 022 002 05
012500 2200N 08623W 8435 01470 //// +178 //// 071038 040 023 002 01
012530 2201N 08625W 8429 01480 //// +180 //// 077035 037 023 001 05
012600 2202N 08626W 8430 01479 9985 +184 +175 078038 038 023 001 03
012630 2204N 08628W 8429 01483 9986 +182 +177 081039 040 020 002 01
012700 2205N 08629W 8432 01484 //// +179 //// 083039 039 022 001 05
012730 2206N 08630W 8426 01487 //// +177 //// 086037 039 019 001 01
012800 2208N 08632W 8436 01481 //// +179 //// 081033 036 019 003 05
012830 2209N 08633W 8425 01494 //// +174 //// 079032 034 020 003 05
012900 2210N 08635W 8429 01495 //// +176 //// 083031 033 021 001 05
012930 2211N 08636W 8430 01493 0005 +176 +172 087029 030 022 001 01
013000 2213N 08637W 8433 01491 0007 +175 +172 091028 030 017 002 03
013030 2214N 08639W 8425 01501 0009 +172 +167 094030 030 014 000 03
013100 2214N 08639W 8425 01501 0006 +178 +177 087033 035 015 003 05
013130 2217N 08642W 8422 01503 0004 +187 +186 081032 037 016 007 01
013200 2218N 08643W 8408 01517 0008 +187 //// 085040 051 037 023 05
$$
;

[dhweather]

If Nate is going to significantly intensify, this is where it starts. I'm still not sold on it happening. Trying to get vertical alignment in its structure with forward speed increasing will be difficult.

[NDG]

Wow, look at these high dewpoints rotating westward towards Nate's path, real high for this time of the year with Miami with a whopping 80 deg F dewpoint. Even 78 deg F dewpoint here in Orlando is a typical July dewpoint.
Good thing for the north central gulf coast that Nate is moving so fast.

[NDG]

I find it hard to believe all the models including the reliable GFS and ECMWF will have greatly underestimated the eventual strength at landfall. Even the CMC is only 998MB and usually it is too intense. They clearly are seeing something that would prevent RI.

that's the danger of using modelology and not meteorology

Best phrase ever!

[GCANE]

 https://twitter.com/Jeff_Piotrowski/status/916466895032930304