ATL: CHRIS - Post-Tropical

[StruThiO]

really looking not that good

[MississippiWx]

This looks like an upwelling issue.

[Hammy]

Do the models not take upwelling into account? Most are still forecasting strengthening in the near term even though it's clear that's not going to happen until it moves a decent amount.

[Kingarabian]

Do the models not take upwelling into account? Most are still forecasting strengthening in the near term even though it's clear that's not going to happen until it moves a decent amount.

HWRF does I think.

[xironman]

The water vapor loop shows it sucking in some dry continental air. The gulf stream runs deep and strong there, it would take something quite a bit stronger than Chris to upwell that much.

[cycloneye]

Tropical Storm Chris Discussion Number 11
NWS National Hurricane Center Miami FL AL032018
500 AM EDT Mon Jul 09 2018

After the expansion of deep convection during the evening it
appears that some drier air has been entrained into the
circulation which has caused a general warming of the cloud tops
and some erosion of the deep convection overnight. However, the
banding remains well organized and the overall structure of the
cyclone has not changed appreciably. An Air Force Reserve
reconnaissance aircraft investigating the system has found that the
minimum pressure has dropped to 999 mb, but the flight-level and
SFMR winds still support an initial intensity of 50 kt.

Recent aircraft and satellite fixes indicate that Chris is
drifting southward. Steering currents are expected to remain
quite weak during the next 36 hours as Chris is situated between a
couple of mid-level highs and a mid- to upper-level trough to its
northeast. By late Tuesday, a deep-layer trough moving across the
Great Lakes region should begin to lift Chris out toward the
northeast. The cyclone is predicted to accelerate northeastward
during the remainder of the forecast period as it gets caught in
strong southwesterly flow ahead of the aforementioned trough. The
track models are in good agreement on this general scenario but
there are some differences in how fast Chris accelerates over the
western Atlantic. The new NHC track forecast has been shifted
slightly northwestward to be in better agreement with the latest
guidance, and it remains near the model consensus to account for
the forward speed differences among the various track models.

The cyclone should be able to mix out the dry air that it entrained
while it is located over warm water and in light to moderate
vertical wind shear conditions. This should allow strengthening
during the next couple of days, but there could be some upwelling
beneath the slow moving cyclone which could temper the rate of
intensification. The new NHC track forecast shows a slightly slower
rate of deepening during the next 24 to 36 h, but still forecasts
Chris to become a hurricane later today or tonight, and reach about
the same peak intensity as shown in the previous advisory. The
hurricane should become extratropical by 96 h, and the global models
indicate that steady weakening will occur after that time.


FORECAST POSITIONS AND MAX WINDS

INIT 09/0900Z 32.4N 74.6W 50 KT 60 MPH
12H 09/1800Z 32.4N 74.6W 55 KT 65 MPH
24H 10/0600Z 32.5N 74.7W 65 KT 75 MPH
36H 10/1800Z 33.0N 73.9W 70 KT 80 MPH
48H 11/0600Z 34.2N 72.2W 80 KT 90 MPH
72H 12/0600Z 39.0N 66.4W 80 KT 90 MPH
96H 13/0600Z 45.5N 59.3W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 14/0600Z 49.5N 49.5W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown

[Ian2401]

Recon just got a pressure of 997

[Alyono]

Cracked core like this symbols dry air intrusion within the core. Its gonna have to reset.

https://i.imgur.com/IN6DD14.jpg

dry air is an excuse that is overstated on this forum.

This is a clear case of upwelling. Water temps may be in the low 20s C at this point

[weathaguyry]

It sort of reminds me of Franklin from last year when it had that pocket of dry air in the middle that sort of looked like an eye

[Hypercane_Kyle]

Cracked core like this symbols dry air intrusion within the core. Its gonna have to reset.
https://i.imgur.com/IN6DD14.jpg

dry air is an excuse that is overstated on this forum.

This is a clear case of upwelling. Water temps may be in the low 20s C at this point

I think upwelling is a factor that's limiting thunderstorm growth over what would be an otherwise warm gulf stream, but I'm seeing a large tongue of dry air being wrapped into Chris around the CDO.

[xironman]

Cracked core like this symbols dry air intrusion within the core. Its gonna have to reset.

dry air is an excuse that is overstated on this forum.

This is a clear case of upwelling. Water temps may be in the low 20s C at this point

Ok, at least I had some company
https://www.nhc.noaa.gov/text/refresh/M ... 0843.shtml

Code: Select all

After the expansion of deep convection during the evening it
appears that some drier air has been entrained into the
circulation which has caused a general warming of the cloud tops
and some erosion of the deep convection overnight. However, the
banding remains well organized and the overall structure of the
cyclone has not changed appreciably.

[GCANE]

Satellite shows basically no cloud cover over land during the night.
Boundary layer cooled off significantly then.
That low-level cool air very likely entrained into the core.

[seahawkjd]

its abnormally cool and dry here with a north wind. I'm pretty sure that is getting ingested by the storm.

[cycloneye]

A lot of 9's.

[cycloneye]

Tropical Storm Chris Discussion Number 12
NWS National Hurricane Center Miami FL AL032018
1100 AM EDT Mon Jul 09 2018

A NOAA reconnaissance aircraft investigating Chris this morning has
found little change in the overall structure of the cyclone. The
peak 8000-ft wind measured was 60 kt to the south of the center
along with a 51-kt SFMR surface wind. The minimum pressure has also
remained steady at 999 mb during the entire mission which is still
ongoing. Although an eye-like feature has briefly appeared in
WSR-88D Doppler radar data from Morehead City and in satellite
imagery as well, the convection surrounding that feature has been
mostly shallow and ragged. Based on these data, the intensity
remains at 50 kt for this advisory.

Air Force and NOAA reconnaissance fixes the past several hours and
satellite fixes indicate that Chris has moved little. Steering
currents are forecast to remain weak for the next 24 hours or so,
resulting in continued slow movement. By 36 hours, however, a
shortwave trough is forecast to dig southeastward out of Canada and
into the northeastern U.S. and mid-Atlantic states, which should
help to eject the cyclone northeastward. By 48 hours and beyond, the
shortwave trough will help to amplify a deep-layer trough near the
U.S. east coast, causing Chris to accelerate northeastward toward
the Atlantic Canada region. The NHC model guidance continues to show
little cross-track differences, but fairly significant along-track
or speed differences. As a result, the official forecast track
remains close to the consensus track models.

A narrow band of dry mid-level air has wrapped all the way around
and into the inner-core region, which has caused some erosion of the
associated convection, along with some upwelling. However, the
reconnaissance wind data indicated that Chris has a relatively small
radius of maximum winds (RMW) of 15 nmi to the south and about 25
nmi to the north. This well-defined inner-core wind field, coupled
with warm water and low vertical shear conditions, should enable the
cyclone to mix out the dry air later today and tonight, which will
allow for strengthening to begin. The intensification process should
be steady at a near-normal rate for the next 36 hours or so,
followed by gradual weakening in a few days as the waters beneath
Chris begin to cool and the wind shear increases from the southwest.
By 72 hours and beyond, Chris will be over much colder water (SSTs
less than 20 deg C) and within a high shear environment of 30 kt or
more, which will induce a rapid transition to a powerful
extratropical cyclone as the system approaches Newfoundland. The
extratropical low is forecast to interact or merge with a strong
cold front by 96 hours when the cyclone is near Newfoundland, which
will enhance the extratropical transition process. The new intensity
forecast is similar to the previous advisory and shows Chris
reaching hurricane strength by Tuesday. Chris could reach a peak
intensity of 80 kt between the 36 and 48 hour time periods before
weakening begins shortly thereafter.

FORECAST POSITIONS AND MAX WINDS

INIT 09/1500Z 32.2N 74.5W 50 KT 60 MPH
12H 10/0000Z 32.3N 74.4W 55 KT 65 MPH
24H 10/1200Z 32.4N 74.3W 65 KT 75 MPH
36H 11/0000Z 33.3N 73.0W 75 KT 85 MPH
48H 11/1200Z 34.8N 70.9W 75 KT 85 MPH
72H 12/1200Z 40.5N 64.0W 70 KT 80 MPH
96H 13/1200Z 47.0N 55.5W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 14/1200Z 51.1N 41.0W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Stewart

[wxman57]

The low-level water vapor band confirms that dry air is wrapping around the storm. Current dewpoint in Myrtle Beach, SC is 54 degrees! Mid and upper-levels remain moist. Upwelling of cool water is a significant factor as well.

[OuterBanker]

The low-level water vapor band confirms that dry air is wrapping around the storm. Current dewpoint in Myrtle Beach, SC is 54 degrees! Mid and upper-levels remain moist. Upwelling of cool water is a significant factor as well.

Yet, in just over an hour it has filled in.

https://i.imgur.com/6aP7GS5.jpg

[cycloneye]

First pass of the Air Force plane has 997 mbs.

[cycloneye]

[tolakram]

SLIDER CONUS: http://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=conus&x=7292&y=4540&z=3&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider

Meso: http://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=mesoscale_01&x=976.5&y=1042&z=2&im=60&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&p%5B0%5D=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&s=rammb-slider

COD Meso: http://weather.cod.edu/satrad/exper/?parms=meso-meso1-02-96-1-100-1&checked=map&colorbars=