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SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

[Info] Tropical Storm Bertha

I was writing this at 5AM friday morning and forgot to post.. more in the morning..

Well invest 93, (which I was happily ignoring) has gone and turned into Bertha.

While some convection developed near the estimated center during the
past few hours, the circulation of Bertha remains disorganized. In
fact, the hurricane hunter aircraft has been unable to find a center
at 5000 ft this evening. However, surface observations suggested
that there was still a small closed surface circulation when Bertha
moved between Martinique and Dominica a few hours ago. The estimated
center position is on the southwestern edge of the convective
canopy, consistent with the 16 kt of southwesterly shear analyzed by
the SHIPS model. The initial intensity remains 45 kt based on
several SFMR winds of 40-45 kt reported by the aircraft east and
northeast of the center.

While the SHIPS model shows the shear decreasing on Saturday, Bertha
will continue moving through a dry environment during the next 24 to
36 hours. There is also the potential for land interaction with
Puerto Rico and Hispaniola during this time, which could disrupt the
small circulation. Given all of these factors, little change in
intensity is expected through 36 hours. After that time, if Bertha
survives, the environment is expected to become more favorable for
intensification with warming SSTs, increasing moisture, and lower
vertical shear. Much of the intensity guidance shows Bertha reaching
hurricane strength in 72 to 96 hours, and the official forecast
follows suit. The new NHC intensity forecast has been adjusted
upward from 48 to 96 hours, but remains a little below the ivcn
intensity consensus. Note that it is possible that the combination
of shear, dry air, and land interaction could cause Bertha to
degenerate to a tropical wave during the next 36 hours, followed by
possible regeneration when the system reaches the more favorable
environment later in the forecast period.

The initial motion estimate is 290/19, as Bertha is being steered
west-northwestward by a deep-layer subtropical ridge over the
western Atlantic. The ridge will begin to erode after 24 hours as a
mid- to upper-level trough moves through the eastern United States,
which should allow Bertha to turn northwestward and then northward
by 3 days. After that time, Bertha is expected to complete
recurvature and accelerate northeastward into the North Atlantic.
The track model guidance remains in good agreement on this general
scenario, however, there is a fair bit of spread in how sharply
Bertha will recurve. The GFS and gefs ensemble mean lie on the
eastern edge of the guidance envelope, with the ECMWF, HWRF, and
GFDL showing a more gradual turn and a track a little farther west.
Through 36 hours the new NHC track is an update of the previous one.
After that time, the official forecast has been nudged toward the
left, but lies a little to the right of the middle of the guidance
envelope.

Forecast positions and Max winds

Init 02/0300z 15.7n 63.0w 45 kt 50 mph
12h 02/1200z 16.9n 65.5w 45 kt 50 mph
24h 03/0000z 19.0n 68.6w 45 kt 50 mph
36h 03/1200z 21.4n 71.2w 45 kt 50 mph
48h 04/0000z 24.0n 73.2w 50 kt 60 mph
72h 05/0000z 30.0n 73.5w 60 kt 70 mph
96h 06/0000z 35.5n 68.0w 65 kt 75 mph
120h 07/0000z 40.0n 59.0w 60 kt 70 mph

$$
forecaster Brennan


dandelion
Premium,MVM
join:2003-04-29
Germantown, TN
kudos:5
Will keep an eye on it, thanks!


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
What distracted me this morning was an Email from a forecaster at the NWS office in Jax saying not to expect any significant local impact. I sent her an Email back to ask "isn't that the same forecast the last time Bertha made an appearance?" 2 days later the entire East coast of Florida was evacuated from the Keys to Georgia..


dandelion
Premium,MVM
join:2003-04-29
Germantown, TN
kudos:5
Am looking to move closer to the coast in a month so plan to start watching the forecast more.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

reply to SmokChsr
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As of Now Bertha continues to be forecasted to remain well East of the US mainland. By Monday afternoon we should know if Bertha has turned on schedule or if she is going to confuse everyone.

Last Updated 8/2/2014, 5:00:00 PM (Eastern Standard Time)
Location 18.4N 68.5W Movement WNW at 22 mph
Wind 45 MPH Pressure: 1010 MB

Bertha has maintained some organized convection over the eastern
semicircle during the past several hours. However, the system
barely qualifies as a tropical cyclone, as a combination of NOAA
hurricane hunter aircraft and surface data cannot definitively close
off the circulation. The initial intensity is reduced to 40 kt
based on a combination of surface observations and data from the San
Juan WSR-88D Doppler radar. It should be noted that Bertha
continues to suffer from dry air entrainment and northwesterly
vertical shear, and advisories could be discontinued tonight or
Sunday if the system becomes any less organized.

The initial motion is now 300/19. Bertha is approaching the
southwestern edge of the subtropical ridge and should turn
northwestward during the next several hours. A turn toward the
north should occur in about 48 hours as Bertha moves between the
ridge and a deep-layer trough over the southeastern United States.
After that, the cyclone should turn northeastward as it enters the
mid-latitude westerlies. The track guidance remains in good
agreement on this scenario, and the new forecast track is
again generally similar to the previous track.

There are now three possible scenarios for the intensity of Bertha.
The scenario for the official forecast is that Bertha survives its
current lack of structure, land interaction, and dry air
entrainment long enough to reach a more favorable environment in
about 36 hours. At that point, it would likely intensify until
the onset of extratropical transition in 96-120 hours. Using this
scenario, the new intensity forecast is similar to the previous
forecast and calls for Bertha to become a hurricane in about 96
hours. The second scenario is that Bertha degenerates to a tropical
wave as it passes over Hispaniola, with possible regeneration later
when the system reaches the more favorable environment. A new third
possibility involves a low pressure area currently developing over
the northwestern Bahamas. The UKMET and navgem forecast this low to
get strong enough to absorb Bertha in 48 hours or so, while the
other models are less bullish on the its development. Later model
runs should help determine the likelihood of this scenario.

Forecast positions and Max winds

Init 02/2100z 18.4n 68.5w 40 kt 45 mph
12h 03/0600z 20.0n 70.3w 40 kt 45 mph
24h 03/1800z 22.5n 72.7w 40 kt 45 mph
36h 04/0600z 25.1n 74.1w 45 kt 50 mph
48h 04/1800z 28.0n 74.1w 50 kt 60 mph
72h 05/1800z 34.0n 70.5w 60 kt 70 mph
96h 06/1800z 38.5n 63.0w 65 kt 75 mph
120h 07/1800z 43.5n 53.0w 50 kt 60 mph

$$
forecaster Beven


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 recommendation

reply to SmokChsr
The 11PM discussion for Bertha doesn't sound so encouraging for the storm. Lookin like she may kick the bucket, but don't completely ignore her just yet.

Last Updated 8/2/2014, 11:00:00 PM (Eastern Standard Time)
Location 19.5N 69.7W Movement NW at 22 mph
Wind 45 MPH Pressure: 1010 MB

While there has been some increase in the coverage of cold
convective tops associated with Bertha this evening, the cyclone
remains disorganized. Surface observations from the Dominican
Republic have not definitively shown a closed circulation, and it is
possible that what surface circulation there was has been disrupted
by land interaction. We will maintain Bertha as a tropical cyclone
for now, but advisories could be discontinued on Sunday if the
organization of the system does not improve. The initial intensity
remains 40 kt based on rain-adjusted SFMR winds reported by the Air
Force hurricane hunter aircraft well east of the center prior to 00
UTC.

The initial motion estimate of 310/19 is based on a blend of the
latest satellite imagery and continuity. The synoptic reasoning
for the track forecast remains unchanged. Bertha will continue
moving northwestward along the southwestern periphery of the
subtropical ridge tonight and Sunday. Then the cyclone will
turn northward on Monday between the ridge and a deep-layer trough
over the southeastern United States, followed by a northeastward
acceleration into the mid-latitude westerlies. The track model
guidance remains in good agreement on this general scenario.
However, the models have shifted to the left this cycle at 48 hours
and beyond, showing a more gradual recurvature. The NHC track
through 36 hours is largely an update of the previous one. After
that time, the official forecast has been adjusted to the left of
the previous one, but now lies along the right side of the guidance
envelope.

There continue to be three possible scenarios for the intensity of
Bertha. The official forecast assumes that Bertha will survive its
current lack of structure, land interaction, shear, and dry air
entrainment long enough to reach a more favorable environment in
24-36 hours. At that point, the environment would likely allow for
intensification until extratropical transition begins after 96
hours. The new NHC intensity forecast is similar to the previous one
and calls for Bertha to become a hurricane in 4 days, and is close
to the latest ivcn intensity consensus. An alternate scenario is
that Bertha degenerates to a tropical wave in the next 12 to 24
hours, with possible regeneration later when the system reaches the
more favorable environment. A third possibility involves a trough of
low pressure currently situated over the central and northwestern
Bahamas. The 1200 UTC runs of the UKMET and navgem forecast the
low to absorb Bertha in 48 hours or so, while the latest GFS and
ECMWF runs keep this system weaker and maintain Bertha through the
forecast period. Later model runs should help refine the likelihood
of this scenario.

Forecast positions and Max winds

Init 03/0300z 19.5n 69.7w 40 kt 45 mph
12h 03/1200z 21.5n 71.8w 40 kt 45 mph
24h 04/0000z 24.1n 73.8w 45 kt 50 mph
36h 04/1200z 27.2n 74.4w 45 kt 50 mph
48h 05/0000z 30.4n 73.8w 50 kt 60 mph
72h 06/0000z 36.0n 69.0w 60 kt 70 mph
96h 07/0000z 41.0n 60.0w 65 kt 75 mph
120h 08/0000z 45.0n 50.0w 50 kt 60 mph...Post-trop/extratrop

$$
forecaster Brennan


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL

1 edit

1 recommendation

reply to SmokChsr
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It's Monday Morning and Bertha is doing just fine, still expected to stay away from the US mainland.

Of more interest to me right now is an area of disturbance that was just East of South Florida, that has done a side step over to just West of Key West. It was thought that it would get absorbed by Bertha, but instead it has "stepped out" of Bertha's path and may be trying to do something on it's own. Current radar doesn't indicate any definite rotation pattern as of yet. I'll watch it a bit more and see if the NHC takes interest in it this morning.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
reply to SmokChsr
Bertha is well on her way to the North Atlantic.. She's movin fast and pretty much just a wide spread low.

The other system that jumped across Florida yesterday jumped back across and is trying to catch up to Bertha.

So basically this one is done, as far as the SouthEast is concerned..


dandelion
Premium,MVM
join:2003-04-29
Germantown, TN
kudos:5
reply to SmokChsr
Good to hear.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
Somfin goin on out at 27N 50W, but it hasn't got the NHC's attention yet. It's moving SE at a pretty good clip and has good rotation, but not much convection. If it keeps heading into warmer water I would expect it may be a concern. It sorta looped down away from Bertha. I might be crazy, (well that's not much question about that) but I expect it'll be an "Invest" by Wed evening.