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WxWatcher007

Category Five Hurricane Dorian

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2 minutes ago, Tatamy said:

18z HWRF has the western eyewall coming ashore at Titusville at 102 hours.  Pressure 952mb.  This is still well east of the 12z run but much worse for the NE Florida coast.

Please refresh my memory.  Is landfall considered when a portion of the eyewall reaches shore or the center of the eye itself?

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Just now, Indystorm said:

Please refresh my memory.  Is landfall considered when a portion of the eyewall reaches shore or the center of the eye itself?

Center of the eye.

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Just now, Indystorm said:

Please refresh my memory.  Is landfall considered when a portion of the eyewall reaches shore or the center of the eye itself?

Technically it is when the center of the eye comes ashore.

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Rapid Intensification Guidance

 AL052019 190830 18UTC
 Storm Located at           :     24.80     70.30
 Guidance run with Vmax [kt]:   100.


 Initial Conditions: 
 Predictor                Value    Favorable(F)/Unfavorable(U) 
 INTENSITY (VMAX) [kt]   100.00             U
 12-H DELTA VMAX  [kt]    10.00             F
 CORE SIZE        [km]     5.40             F
 CONVECTION <-50C [%]     74.00             N
 CONVECTION <-60C [%]     32.00             N
 IR CORE SYMMETRY [K]      9.80             F
 TC SIZE          [%]     88.00             F


 Forecast Conditions:
 Predictor              Value                                         Favorable(F)/Unfavor(U) 
                           6    12    18    24    30    36    42    48  6 12 18 24 30 36 42 48
 Wind Shear [kt]        13.3  18.2  17.9  12.4  13.7  17.2  17.1  12.7  F  F  F  F  F  F  F  F
 Ocean Heat [kJ/cm^2]   39.0  34.0  39.0  51.0  56.0  54.0  55.0  58.0  U  U  U  N  N  N  N  N
 Potential [kt]         65.0  65.0  65.0  65.0  65.0  65.0  65.0  65.0  U  U  U  U  U  U  U  U
 200mb Divg [10^6/s]    46.0  24.0   9.0  35.0 -13.0  10.0 -14.0  23.0  N  U  U  N  U  U  U  U
 Humidity 700-500 hPa   59.0  56.0  57.0  57.0  60.0  58.0  59.0  62.0  U  U  U  U  N  U  U  N
 T Advectio [10^6 K/s]  13.3  18.2  17.9  12.4  13.7  17.2  17.1  12.7  F  F  F  F  F  F  F  F


    Probabilities[%] of Rapid intensification
 Thresholds   LDA-Method  LRE-Method  CONSENSUS
 20kt / 12h       33.4%       20.9%       27.1%
 25kt / 24h       34.7%       36.6%       35.7%
 30kt / 24h       30.2%       33.4%       31.8%
 35kt / 24h       25.5%       33.4%       29.4%
 40kt / 24h       20.4%       17.5%       18.9%
 45kt / 36h       60.0%       22.3%       41.2%
 55kt / 36h       15.2%       13.8%       14.5%
 55kt / 48h       11.2%        7.4%        9.3%
 70kt / 48h        0.0%        0.0%        0.0%
 65kt / 72h        0.0%        0.0%        0.0%

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000000 2527N 07052W 7485 02313 9772 +141 //// 137115 118 107 012 01
000030 2526N 07054W 7486 02236 9689 +142 //// 136122 125 114 015 01
000100 2525N 07056W 7491 02155 9583 +164 +155 132091 111 114 017 00
000130 2524N 07058W 7526 02079 9510 +214 +147 114045 055 112 027 03
000200 2522N 07100W 7529 02065 9495 +222 +120 102021 028 /// /// 03
000230 2520N 07100W 7528 02071 9496 +227 +106 094005 009 026 000 03
000300 2518N 07100W 7501 02105 9503 +223 +110 235007 009 025 000 03

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Local news met here just mentioned that hurricane hunters found an intensifying storm but failed to mention it’s likely already a CAT4. Instead went with the NHC forecast of maintaining CAT3 status through tomorrow. Can’t say I blame her but you could see the concern and mental gymnastics as she was giving the forecast. 

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have a feeling a massive evacuation notice is coming in the morning for palm beach county northward.

highway patrol was setting up the inside shoulder to be used as an additional travel lane on 95 when I was headed home tonight starting at the Martin/palm beach line 

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4 minutes ago, NJwx85 said:

Local news met here just mentioned that hurricane hunters found an intensifying storm but failed to mention it’s likely already a CAT4. Instead went with the NHC forecast of maintaining CAT3 status through tomorrow. Can’t say I blame her but you could see the concern and mental gymnastics as she was giving the forecast. 

I don't know if NHC was saying through tomorrow - I believe they have an 11 pm update to come.  They did acknowledge the 950 mb central pressure in their writeup.  The one notable thing is that it had been chugging along at 12 mph and has slowed to 10 mph.

Quote
DISCUSSION AND OUTLOOK
----------------------
At 800 PM EDT (0000 UTC), the well-defined eye of Hurricane Dorian
was located near latitude 25.3 North, longitude 71.0 West. Dorian
is moving toward the west-northwest near 10 mph (17 km/h). A slower
west-northwestward to westward motion should begin tonight and
continue into early next week.  On this track, the core of Dorian
should move over the Atlantic well north of the southeastern and
central Bahamas tonight and tomorrow, be near or over the
northwestern Bahamas on Sunday, and be near the Florida east coast
late Monday.

Data from a NOAA Hurricane Hunter aircraft indicate that the
maximum sustained winds have increased to near 125 mph (205 km/h)
with higher gusts.  Dorian is a category 3 hurricane on the
Saffir-Simpson Hurricane Wind Scale.  Additional strengthening is
forecast, and Dorian is anticipated to remain an extremely dangerous
hurricane while it moves near the northwestern Bahamas and
approaches the Florida peninsula into early next week.

Hurricane-force winds extend outward up to 30 miles (45 km) from
the center and tropical-storm-force winds extend outward up to 115
miles (185 km).

The latest minimum central pressure based on data from a NOAA
reconnaissance aircraft is 950 mb (28.05 inches).

 

 

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Beyond catastrophic for the Bahamas.

If Dorian follows the revised models, grows even more in diameter/extent [as it has] and landfalls as a Cat 4 or 5 [yeah, it's now possible], and then drags its' eye up almost the entire length of Florida's east coast, staying half over water, Dorian will be enormously expensive. Both in lives lost and damaged, and in property.

Have to agree that Dorian will be a solid Cat 4 by the 11PM forecast discussion [already looks a low 4]. Will it continue strengthening beyond that?

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9 minutes ago, Hurricane Agnes said:

 

recon_NOAA2-2105A-DORIAN2_zoom.png

Three wind barb 'pennants' by noon tomorrow...

[each pennant equals 50kts, long flag/line 10kts, short line 5kts]

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Does anyone have the calculated MPI (max potential intensity) along the current most likely path?  With numbers near 950 mb I would imagine we are not too far off what can reasonably be expected in terms of max strength for the next day or so.  

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Will a expanding storm that intensify’s More rapidly then forecast “pump up the ridge “ in anyway 

Part of why I ask is it seems small deviations in competing features for steering Dorian could make a difference when steering collapses and maybe this more intense storm could pump ridge a tad and leave him under its influence longer (push him further west ) before potential stall (if that idea holds any weight )

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1 minute ago, Hotair said:

Does anyone have the calculated MPI (max potential intensity) along the current most likely path?  With numbers near 950 mb I would imagine we are not too far off what can reasonably be expected in terms of max strength for the next day or so.  

There was a tweet about that -

 

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000
WTNT65 KNHC 310027
TCUAT5

Hurricane Dorian Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL052019
830 PM EDT Fri Aug 30 2019

...DORIAN STRENGTHENS TO A CATEGORY 4 HURRICANE...

Data from the NOAA Hurricane Hunters indicate that Dorian has
strengthened to an extremely dangerous category 4 hurricane with
maximum sustained winds near 130 mph (215 km/h). This increase in
intensity will be reflected in the forecast issued at 1100 pm EDT
(0300 UTC).

SUMMARY OF 830 PM AST...0030 UTC...INFORMATION
----------------------------------------------
LOCATION...25.3N 71.0W
ABOUT 400 MI...645 KM E OF THE NORTHWESTERN BAHAMAS
ABOUT 575 MI...925 KM E OF WEST PALM BEACH FLORIDA
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.05 INCHES

$$
Forecaster Cangialosi/Latto

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9 minutes ago, StantonParkHoya said:

The good news is that it’s undergoing rapid intensification days before landfall.  Not likely to hold for days.

There is zero reason to expect it to weaken. 

There might be an ERC, but otherwise, this post has no substance. 

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9 minutes ago, STxVortex said:

...If Dorian follows the revised models, grows even more in diameter/extent [as it has] and landfalls as a Cat 4 or 5 [yeah, it's now possible], and then drags its' eye up almost the entire length of Florida's east coast, staying half over water, Dorian will be enormously expensive. Both in lives lost and damaged, and in property...

Remembering when Irma became less of a treat to Tampa Bay less than 24 hours (maybe 12?) before it was supposed to scrape the Gulf Coast entering right up our street in Gulfport Florida as a Cat 3 or 4. What a relief when we realized that was not going to happen!
Then at about 10:30 PM that same day as it was a much weaker storm miles away over Polk or Lake County our personal weather station recorded a 39 MPH gust as we lost power. The next couple hours we sat on our front porch watching blue flashes of transformers blowing up all around us. An old laurel oak tree twisted and bent in the winds but did not fall down, until two days later when no wind was blowing and it almost landed on our neighbor's house. Our power was out two weeks and we had a lot of debris and clean up to do in our yard. I was doing business on my laptop with my car running supplying power for the laptop and a wifi internet access device for days until we couldn't stand the heat and humidity anymore and had to find a hotel until our power came back on. So a near miss might be a relief, but that does not mean it will not be a nightmare for tens or hundreds of thousands of families, businesses, and communities.

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One thing to watch for(especially wrt intensity duration) is how the structure of Dorian changes over time. As of right now, based on recon precip, microwave and satellite, Dorian *may* be heading toward more of an annular structure. If this were to happen, Dorian would probably be less susceptible to EWRCs and therefore maintain intensity longer. Not to mention that annular storms are also somewhat more resilient than their banded counterparts, with their dense, compact inner cores.

Should pass over a slightly cooler eddy of water tomorrow, which may slow strengthening some however.

cf191f8aa2de1904eb615781b01dc9a0.jpg


Notice how there is little precip being measured by recon outside the core windfield. 

0a286d0a938450e3f3e1dc8c390cfda0.png
https://gyazo.com/0a286d0a938450e3f3e1dc8c390cfda0

 

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I have never seen that MPI actually work out.  Hurricanes while they rely on the energy available to them via the oceanic heat content and the warmth of the SSTs, the atmosphere also plays a large part.  If the atmosphere is ready for explosive deepening, and the ocean is warmer than 27.5C, it will intensify, and the ocean is above 29C in the path still, so the MPI should increase ahead of the hurricane.

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1 minute ago, hlcater said:

One thing to watch for(especially wrt intensity duration) is how the structure of Dorian changes over time. As of right now, based on recon precip, microwave and satellite, Dorian *may* be heading toward more of an annular structure. If this were to happen, Dorian would probably be less susceptible to EWRCs and therefore maintain intensity longer. Not to mention that annular storms are also somewhat more resilient than their banded counterparts, with their dense, compact inner cores.

Should pass over a slightly cooler eddy of water tomorrow, which may slow strengthening some however.

cf191f8aa2de1904eb615781b01dc9a0.jpg


Notice how there is little precip being measured by recon outside the core windfield. 

0a286d0a938450e3f3e1dc8c390cfda0.png
https://gyazo.com/0a286d0a938450e3f3e1dc8c390cfda0

 

There is high precip spikes in the northern semicircle, so.  This supports what the IR imagery showed all day long, but Dorian is finally showing a better pattern on IR, convection is increasing in all quadrants.  So I am not buying the annular argument until the spiral bands cease.

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