ATL: FOUR - Remnants - Discussion

[Aric Dunn]

im just interested to see how this and the larger vorticity to its NW interact. that northern vorticity could help keep the circ going long enough to get to a more moist environment as the CMC continues to think as well as other members of the GFS..

In surfing we call this a double up wave. typically ( like all physics and fluids) the amplitude will increase and then they merge creating a stronger wave.

http://www.ssd.noaa.gov/goes/east/tatl/flash-rgb.html

[gatorcane]

12Z UKMET has this into East-Central coast of Florida as a weak low:

[wxman57]

Here's the ASCAT image. The red circle is where the NHC put the center around 12-13Z.

http://wxman57.com/images/ASC.JPG

thats not where it is on satellite.. but not really a big deal at the moment. no convection to call it a TC at the moment. still needs to be watched near bahamas.

Not where it is NOW, but that's where it was around the time the NHC placed the center at 15.3N/50W (12Z), which was just about the time of that ASCAT. It has continued to deteriorate since then. Last NHC advisory will come out this afternoon, right about the time they start advisories on the East Pac system.

TD Four on the left, Invest 95E on the right:

[Gustywind]

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT Fri Jul 7 2017


...SPECIAL FEATURES...

Tropical Depression Four is centered near 15.6N 50.9W at 07/1500
UTC or about 602 nm east of the Lesser Antilles, moving WNW at 18
kt. Estimated minimum central pressure is 1011 mb. [b]The depression
has weakened considerably in the last several hours and is
forecast to degenerate into a low pressure system later today.
Scattered moderate convection and isolated tstms remain in the NW
quadrant within 165 nm of the depression center. Please see the
latest NHC Public Advisory under AWIPS/WMO headers
MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under the
AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details[/b].

[wxman57]

Remnant swirl has appeared one all the convection dissipated (16.4N / 50.8W). It's moving quickly WNW as it opens up:

[Aric Dunn]

Remnant swirl has appeared one all the convection dissipated (16.4N / 50.8W). It's moving quickly WNW as it opens up:

http://wxman57.com/images/swirl.JPG

yes thats what i was saying earlier

[MGC]

Looks to have opened up this afternoon.....MGC

[Aric Dunn]

Looks to have opened up this afternoon.....MGC

definitely still closed. just no convection near the center

[MississippiWx]

TD4 still has a small, yet vigorous low level swirl. If no new convection can ignite near the center, it will weaken quickly.

[Aric Dunn]

its starting to merge with that other large vorticity to the NW it is also a large moisture pouch might help some convection over the next 12 hours or so before the sal gets to that too..

[cycloneye]

Remnants Of Four Discussion Number 8
NWS National Hurricane Center Miami FL AL042017
500 PM AST Fri Jul 07 2017

Satellite data and surface observations indicate that the depression
no longer has a closed circulation, and the cyclone has degenerated
into a tropical wave. Showers associated with the system have
continued to diminish and remain disorganized.

Based on the lack of organization, this will be the last advisory on
this system. The remnants of this cyclone will continue to move
toward the west-northwest today, but environmental conditions are
not favorable for regeneration.


FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 16.5N 52.5W 20 KT 25 MPH...REMNANTS
12H 08/0600Z...DISSIPATED

$$
Forecaster Avila

[Blown Away]

That dreaded MDR does another system in...

[Ntxw]

You can see the SAL behind it getting drawn in. Goes 16 imagery is so stunning

[Aric Dunn]

beg to differ on the "closed Circ" part but agree not enough convection to be classified.

[Kingarabian]

The NASA model with its dry air depiction is really underrated and will be an important tool going forward in regards to waves emerging off Africa. It simply depicts dry air a lot better than any of the other models.

[Evil Jeremy]

It's amazing how many storms are predicted to hit Jacksonville. Yet, it rarely gets hit.

Perhaps, but last year alone Colin & Hermine moved through the area, Julia skirted the coast, and Matthew was thankfully a near miss.

[Sciencerocks]

12Z UKMET has this into East-Central coast of Florida as a weak low:

18z Gfs has good ridging to the north of the remains of 4 through 144 hours and shows nearly the same thing but slightly south...84, 96, 108 hour time frames all show a closed isobar with this system.

Still something to be watched.

http://www.tropicaltidbits.com/analysis ... 0&ypos=228

[Aric Dunn]

Still needs to be watched. models are touchy in situation like this. especially with the other area of vorticity and moisture is merging with.

presently although small new deep convection is firing very near the center... and yes it has a center.

[GCANE]

This is a vampire. Comes alive at night.
Off the scale convection on 85GHz.

[Aric Dunn]

it has now moved under that new recent convection...

I was wondering if this would happen once it started merging with the pouch/vorticity to the NW much higher low and mid level moisture out ahead of it now because of that lobe. the SAL is slowly thinning out over time and now with SW wind in the mid and upper levels though still really light and favorable for development.. the only thing holding this back is the SAL/dry air.