ATL: JOAQUIN - Post-Tropical - Discussion

[CrazyC83]

000
URNT15 KNHC 281938
AF307 0111A CYCLONE HDOB 33 20150928
192800 2847N 06839W 8273 01743 0112 +160 +153 136020 021 021 001 00
192830 2846N 06841W 8273 01743 0109 +160 +153 132020 020 020 001 00
192900 2844N 06842W 8274 01742 0109 +161 +140 134023 024 022 000 00
192930 2843N 06843W 8271 01743 0109 +162 +140 132023 024 020 000 00
193000 2842N 06845W 8275 01739 0107 +163 +149 137021 022 021 000 00
193030 2841N 06846W 8273 01740 0105 +165 +144 135021 021 021 000 00
193100 2840N 06847W 8274 01739 0103 +166 +142 132022 022 022 000 00
193130 2839N 06849W 8273 01739 0101 +170 +136 129021 022 023 000 00
193200 2837N 06850W 8274 01737 0101 +166 +143 132022 023 021 001 00
193230 2836N 06851W 8273 01738 0100 +168 +142 130023 023 023 000 00
193300 2835N 06853W 8273 01737 0099 +168 +149 132025 026 023 000 00
193330 2834N 06854W 8273 01737 0099 +169 +149 129026 026 024 000 00
193400 2833N 06855W 8272 01737 0098 +168 +150 128026 027 023 000 00
193430 2832N 06857W 8277 01732 0100 +165 +146 133026 027 021 000 00
193500 2830N 06858W 8272 01735 0097 +167 +142 133026 026 021 000 00
193530 2829N 06859W 8272 01737 0095 +171 +139 133026 026 022 000 00
193600 2828N 06901W 8273 01734 0094 +172 +142 134026 027 021 000 00
193630 2827N 06902W 8273 01733 0092 +171 +146 135027 028 021 001 00
193700 2826N 06903W 8274 01731 0091 +167 +146 134027 028 022 001 01
193730 2825N 06905W 8275 01728 0088 +175 +141 136027 027 021 001 00
$$
;

[Aric Dunn]

IF there turns out to be some sort of consolidation (which I am highly skeptical of after Erika) I think it might be in the form of the vortex getting sucked under the convection rather than reformation, it almost seems like it's being steered by the MLC at the moment.

In some cases that happens. though because convection is what drives the pressure down the vort that is convection free will weaken as it rotates around the "mean" center. I expect that another vort presently strengthening under the convection and mlc will also become exposed as it too rotates around. This might happen a few times till the shear relaxes and a dominate center can maintain under the convection.

[CrazyC83]

000
URNT15 KNHC 281947
AF307 0111A CYCLONE HDOB 34 20150928
193800 2823N 06906W 8272 01729 0085 +174 +142 133026 027 022 000 00
193830 2822N 06907W 8274 01727 0086 +171 +142 127024 025 021 001 00
193900 2821N 06909W 8273 01727 0085 +174 +142 128023 024 019 001 00
193930 2820N 06910W 8274 01726 0086 +169 +148 126020 022 020 000 00
194000 2819N 06911W 8275 01723 0087 +166 +148 123019 020 014 001 00
194030 2818N 06913W 8273 01726 0086 +170 +136 119020 020 016 000 00
194100 2816N 06914W 8274 01723 0083 +170 +136 118018 019 018 000 00
194130 2815N 06916W 8272 01724 0081 +170 +135 116018 019 016 000 00
194200 2814N 06917W 8272 01723 0082 +168 +141 115018 019 017 000 00
194230 2813N 06918W 8275 01720 0082 +170 +148 111017 018 019 000 00
194300 2812N 06920W 8275 01720 0081 +168 +149 110018 018 017 000 01
194330 2810N 06921W 8272 01723 //// +165 //// 116018 018 018 000 01
194400 2809N 06922W 8270 01723 //// +166 //// 111018 019 016 000 01
194430 2808N 06924W 8274 01720 0080 +166 +153 108016 018 016 000 00
194500 2807N 06925W 8275 01717 0080 +165 +151 111016 016 017 000 03
194530 2805N 06926W 8270 01723 0080 +165 +145 112016 016 016 000 00
194600 2804N 06927W 8274 01720 0081 +169 +142 111016 016 015 000 00
194630 2802N 06928W 8273 01721 0080 +170 +142 109016 017 014 001 00
194700 2801N 06929W 8275 01720 0078 +170 +140 108016 017 015 000 00
194730 2800N 06930W 8268 01727 0077 +173 +139 103016 017 016 000 00
$$
;

[LarryWx]

If the 12Z GFS/Euro happen to be close to being accurate about progged shear, then this drop in shear may occur very soon. The 12Z Euro actually has shear going down to under 10 knots starting shortly and staying under 10 knots through at least Fri.

[Hybridstorm_November2001]

Wow I stop watching the Tropics for a few days and this happens.

Another factor to take into consideration is tides are running high all up and down the Eastern Seaboard this week. In fact we are at the peak of the highest tide cycle in years. I sure hope this thing stays weak.

[gatorcane]

51 minutes until the NHC update. Should be an interesting read.

By the way it looks like the system is trying to develop some banding-like features on the SE side. The new LLC that may be forming under the convection is not moving much it seems.

Also, will the 18Z GFS turn bullish I wonder? That run starts in 1 1/2 hours.

[Weatherwatcher98]

51 minutes until the NHC update. Should be an interesting read.

By the way it looks like the system is trying to develop some banding-like features on the SE side. The new LLC that may be forming under the convection is not moving much it seems.

Also, will the 18Z GFS turn bullish I wonder? That run starts in 1 1/2 hours.

Like I said the GFS showed this yesterday will be interesting to see what it shows now because it had 99L stronger coming off the SE coast

[LarryWx]

51 minutes until the NHC update. Should be an interesting read.

By the way it looks like the system is trying to develop some banding-like features on the SE side. The new LLC that may be forming under the convection is not moving much it seems.

Also, will the 18Z GFS turn bullish I wonder? That run starts in 1 1/2 hours.

With all of these goings on between the huge shifts on most 12Z models and the current obs, I have to think that FL is far from safe at this point. The uncertainty levels right now are very high to say the least.

[Hammy]

Center seems to be SE of the vortex now. Hopefully they do one more pass, SE-NW so we can see what exactly is going on in that blob of convection.

[NDG]

The surface COC is clearly the naked LLC moving south now, the circulation SE of it is the MLC.

[gatorcane]

NHC discussion is out and there words low confidence were mentioned a number of times of course...

[Hammy]

The surface COC is clearly the naked LLC moving south now, the circulation SE of it is the MLC.

Cloud flow to the east of the vortex is all west to east, so it's now rotating around a larger circulation as a few earlier have pointed out might happen. The vortex itself is likely no longer closed.

[cycloneye]

TROPICAL DEPRESSION ELEVEN DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL112015
ISSUED BY THE NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
500 PM EDT MON SEP 28 2015

The low-level center has become well exposed due to continued
northwesterly shear of 20 kt or more, with the mid-level
center displaced well to the southeast of the low-level center.
Flight-level and SFMR-observed wind data from an Air Force
reconnaissance aircraft showed that the maximum winds remain near
30 kt. This is also consistent with the latest Dvorak estimates
from SAB and TAFB.

The center of the depression has been moving well to the left of
the previous track, with the initial motion estimated to be 270/05
kt. In addition to the more westward initial motion, there have
been significant changes in the model guidance, with the latest
ECMWF forecast taking the cyclone much farther south and west than
the GFS in 3-5 days. This appears to be the result of enhanced
mid-level ridging to the north of the cyclone in the ECMWF at that
time frame. This has necessitated a significant southwestward
shift of the official forecast, although for continuity the new NHC
track does not take the cyclone as far to the southwest as the
ECMWF. Given the large spread now seen in the dynamical track
guidance, confidence in the track forecast is rather low.

The strong shear over the system is likely to continue for at least
the next 12-24 hours and given the large displacement between the
low- and mid-level centers, no intensification is anticipated in
the short term. The dynamical guidance indicates some relaxation
of the shear in a day or two, so the official forecast shows the
cyclone strengthening into a tropical storm later on Tuesday. This
is close to the intensity model consensus through 48 hours, and a
little below it thereafter. Given the large uncertainty in the
track forecast, there is also uncertainty as to what kind of
environment the cyclone will encounter during the forecast period,
which also leads to low confidence in the official intensity
forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 27.5N 70.2W 30 KT 35 MPH
12H 29/0600Z 27.7N 71.0W 30 KT 35 MPH
24H 29/1800Z 27.9N 72.0W 35 KT 40 MPH
36H 30/0600Z 28.3N 72.8W 40 KT 45 MPH
48H 30/1800Z 28.6N 73.4W 45 KT 50 MPH
72H 01/1800Z 30.0N 74.0W 45 KT 50 MPH
96H 02/1800Z 33.0N 74.0W 45 KT 50 MPH
120H 03/1800Z 38.5N 73.5W 45 KT 50 MPH

$$
Forecaster Pasch/Hayes

[Weatherwatcher98]

Good News and maybe 99L not strengthning actually helped the NE

[CrazyC83]

Good News and maybe 99L not strengthning actually helped the NE

A weaker 99L likely would prevent any phasing back...since that is dependent on a deep upper-level low to the southwest. But the blocking ridge to the north is still there.

[xironman]

Center seems to be SE of the vortex now. Hopefully they do one more pass, SE-NW so we can see what exactly is going on in that blob of convection.

I would expect two more VDMs.

[emeraldislenc]

They bumped it a little more to the west. Will be interesting to see the 11 pm advisory. The remark about low confidence is interesting as well.

[xironman]

Good News and maybe 99L not strengthning actually helped the NE

A weaker 99L likely would prevent any phasing back...since that is dependent on a deep upper-level low to the southwest. But the blocking ridge to the north is still there.

I don't know. As far as the east coast goes TD 11 will be in the middle latitudes by the time it gets any where near it. Therefore the 500mb evolution will be the guide to what happens. No matter what with the current pattern 99L would be on the wrong side of the trough and would not matter too much anyways.

[abajan]

HAMMY standing ground to the professional MET....LOVE IT!! Though I agree this is likely going to be a named stormed and possibly a strong one and is at least a threat from NC north

Where's the S2K disclaimer?

[Hammy]

Is the recon mission over? It hasn't updated in an hour.