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NorthGeorgiaWX

Hurricane Dorian (05L)

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Notice the flurry of activity with each model run. 🙂 We need a bowling bar winter storm and you'd see the same thing happening. 🙂

 

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Tuesday, August 27 2 pm Update

BULLETIN
Tropical Storm Dorian Intermediate Advisory Number 13A
NWS National Hurricane Center Miami FL       AL052019
200 PM AST Tue Aug 27 2019

...DORIAN'S CENTER REFORMS FARTHER NORTH...
...HEAVY RAINS AND GUSTY WINDS STILL AFFECTING THE SOUTHERN LEEWARD
ISLANDS...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...15.0N 62.0W
ABOUT 70 MI...110 KM WNW OF MARTINIQUE
ABOUT 370 MI...595 KM ESE OF PONCE PUERTO RICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


WATCHES AND WARNINGS

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Watch is in effect for...
* Puerto Rico
* Dominican Republic from Isla Saona to Samana

A Tropical Storm Warning is in effect for...
* Puerto Rico
* Dominican Republic from Isla Saona to Samana

A Tropical Storm Watch is in effect for...
* Saba and St. Eustatius
* Dominican Republic from Isla Saona to Punta Palenque
* Dominican Republic from Samana to Puerto Plata


DISCUSSION AND OUTLOOK
----------------------
At 200 PM AST (1800 UTC), data from an Air Force Reserve
reconnaissance aircraft and the Martinique radar indicate that the
center of Tropical Storm Dorian has reformed farther north near
latitude 15.0 North, longitude 62.0 West.  Dorian is moving toward
the west-northwest near 13 mph (20 km/h), and this motion is
expected to continue through tonight, followed by a turn toward the
northwest on Wednesday
.  On the forecast track, the center of Dorian
will move across the eastern and northeastern Caribbean Sea during
the next few days, passing near or south of Puerto Rico on
Wednesday, move near or over eastern Hispaniola Wednesday night, and
move north of Hispaniola on Thursday.  On Thursday night and Friday,
the center of Dorian is forecast to move near the Turks and Caicos
and southeastern Bahamas.

Maximum sustained winds remain near 50 mph (85 km/h) with higher
gusts. Slow strengthening is forecast during the next 48 hours, and
Dorian is forecast to be near hurricane strength when it moves close
to Puerto Rico and eastern Hispaniola.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure based on data from the
reconnaissance aircraft is 1005 mb (29.68 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL:  Dorian is expected to produce the following rain
accumulations through Thursday:

Martinique to Saint Vincent...3 to 6 inches, isolated 10 inches.
Grenadines to Grenada...1 to 3 inches.
Guadeloupe to Dominica...1 to 4 inches.
Puerto Rico and Dominican Republic...4 to 6 inches, isolated 8
inches.
U.S. Virgin Islands...1 to 3 inches, isolated 4 inches.

This rainfall may cause life-threatening flash floods.

WIND:  Tropical storm conditions are diminishing over the Lesser
Antilles. Tropical storm conditions are expected and hurricane
conditions are possible in Puerto Rico on Wednesday and in portions
of the Dominican Republic late Wednesday and Thursday.

SURF:  Swells generated by Dorian should gradually subside in the
Lesser Antilles by this evening. Swells are expected to increase
along the southern coasts of Puerto Rico and Hispaniola on Wednesday
and they could cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

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The conditions over the Bahamas looks ripe for rapid intensification so I guess it will come down to whether or not it establishes an organizational structure that can take advantage of the environment. Hopefully it's track through all the dry air, shear, and land interactions will keep it a messy system. 

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Bastardi just issued a "Raging Weather Bull" video, now confident for a CAT 1 landfall in central Florida. The west bend toward Florida is an indicator of intensification. I can't post the Euro wind swath, but gust over 100 mph at landfall and very high winds as it cross the peninsula. Gets stronger once it hits the northern Gulf.

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Posted (edited)

Things beginning to look a little more interesting  for all.  Wonder what is changing to allow it to continue nw movement after landfall?  Most of the earlier models had it hooking or going n.  Maybe strength of the hurricane?

Edited by RickyD
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11 minutes ago, RickyD said:

Things beginning to look a little more interesting  for all.  Wonder what is changing to allow it to continue nw movement after landfall?  Most of the earlier models had it hooking or going n.  Maybe strength of the hurricane?

Atlantic ridge building in from the east. That is what's forcing the turn. How long it continues west/northwest is to be seen, and probably where we'll see some variations for w while. 

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16 minutes ago, RickyD said:

Things beginning to look a little more interesting  for all.  Wonder what is changing to allow it to continue nw movement after landfall?  Most of the earlier models had it hooking or going n.  Maybe strength of the hurricane?

From what I can tell it has to do with steering from the Western Atlantic Ridge thumbing down the east coast. Clockwise flow around it generates westerly steering. The GFS moves this feature out quicker and thus the sooner turn North. 15669352378042099866764988067404.thumb.jpg.92a35dc7ee25cf0700b3494c24093018.jpg

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18 minutes ago, KingOfTheMountains said:

465.57 kB · 0 downloads

From what I can tell it has to do with steering from the Western Atlantic Ridge thumbing down the east coast. Clockwise flow around it generates westerly steering. The GFS moves this feature out quicker and thus the sooner turn North. 15669352378042099866764988067404.thumb.jpg.92a35dc7ee25cf0700b3494c24093018.jpg

Yep, it's the ridge building in that's causing the turn to the west. 

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For the short term this looks significant. It could very easily wobble back on line with the suite but hard to ignore potential downstream impacts if this continues to happen. 

 

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Tuesday, August 27, 5 pm Update

Tropical Storm Dorian Discussion Number  14
NWS National Hurricane Center Miami FL       AL052019
500 PM AST Tue Aug 27 2019

Dorian's convective pattern has continued to fluctuate this
afternoon due to some interaction with the Windward and Leeward
Islands, but mainly due to intrusions of very dry mid-level air. A
10-mile wide eye feature developed in Martinique and Guadeloupe
radar data between 1500-1600 UTC and again between 1700-1800 UTC.
But this feature had been short-lived due to erosion of the
inner-core convection caused by dry air entrainment, although a
recent burst of deep convection has developed near and over the
low-level center. Dorian's upper-level outflow has continued to
expand and is very symmetrical. The initial intensity has been
maintained at 45 kt based on earlier aircraft flight-level and SFMR
surface wind data.

Despite the center redeveloping farther north, radar and recon
fixes indicate that the motion remains west-northwestward or
300/11 kt. Due to the more northward initial position, the new
forecast track was shifted 30-60 n mi northeast of the previous
one track through 96 hours
. The global models are in good agreement
on Dorian moving west-northwestward tonight and then turning
northwestward on Wednesday, bringing the cyclone's center near
or over the central or western portions of Puerto Rico
. After
clearing the island by early Thursday, Dorian is forecast to move
cyclonically around the eastern portion of a southwestward-moving
mid/upper-level low on days 3-5. The evolution of the upper-low and
how strong the mid-level ridge to the north builds in behind the low
and across the southeastern U.S. will determine when and how sharp
Dorian's turn back the west-northwest will occur. The new NHC track
is close to a blend consensus models TVCN, HCCA, and FSSE, and
brings Dorian near the east-central Florida coast in 120 hours.

Users are reminded not to focus on the details of the extended track
forecast as the average 5-day track error is around 200 miles.

Dry air should continue to plague Dorian for the next 24 hours or
so, resulting in only slow strengthening. Land interaction with
Puerto Rico should significantly weaken the small cyclone, thus the
intensities were lowered at 36 and 48 hours
. On days 3-5, the models
continue to indicate that the upper-level flow pattern and shear
conditions should favor strengthening, especially since Dorian will
be moving over SSTs greater than 29 deg C and into a moist mid-level
environment. The dynamical models such as the GFS, UKMET, and ECMWF
are now showing more strengthening than previous runs, but still
remain well below the statistical SHIPS and LGEM intensity models,
which bring Dorian to category 1 or 2 strength by day 5
. The
official intensity forecast remains a compromise between the these
two extremes, and is close to the HCCA and FSSE consensus models.
Given the large spread in the guidance, there remains lower-than-
normal confidence in the intensity forecast, especially on days 4
and 5.

Key Messages:

1. Tropical storm conditions are expected in the U.S. Virgin Islands
and Puerto Rico on Wednesday and in portions of the Dominican
Republic Wednesday night and Thursday. Hurricane conditions are
possible in Puerto Rico and portions of the Dominican Republic.

2. Heavy rainfall over portions of Puerto Rico and the Dominican
Republic could produce flash flooding during the next few days.
Heavy rains are expected to occur over portions of the Bahamas and
Florida later this week and into early next week.

3. The threat of tropical storm or hurricane conditions, along with
storm surge, in the Bahamas and along portions of the Florida east
coast have increased. Residents in these areas should monitor the
progress of Dorian and ensure that they have their hurricane plan in
place.

4. Uncertainty in the intensity forecast later this week remains
higher than usual due to the potential for Dorian's interaction with
Puerto Rico and Hispaniola to weaken the storm.

FORECAST POSITIONS AND MAX WINDS

INIT  27/2100Z 15.3N  62.5W   45 KT  50 MPH
 12H  28/0600Z 16.2N  64.1W   50 KT  60 MPH
 24H  28/1800Z 17.6N  66.2W   55 KT  65 MPH
 36H  29/0600Z 19.1N  67.8W   40 KT  45 MPH
 48H  29/1800Z 20.8N  69.2W   45 KT  50 MPH
 72H  30/1800Z 24.2N  72.2W   55 KT  65 MPH
 96H  31/1800Z 26.7N  76.1W   60 KT  70 MPH
120H  01/1800Z 28.2N  80.6W   60 KT  70 MPH...NEAR THE FLORIDA COAST

203926_5day_cone_with_line_and_wind.png.cd46990757cab33249b77dff330405b1.png

203926_most_likely_toa_34.png.0d757d7c7edec0de2275b14f3abc5af3.png

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24 minutes ago, NorthGeorgiaWX said:

 

Pretty clear correlation between the further north members and quicker intensification there. But as Ryan Maue pointed out GEFS is a flawed model and from what I've read it is known for underdispersment and is largely unused by the NHC. I know the EPS is showing underdispersment at 12z but from my understanding it's more rare with that model. And may just be because at 12z the new center hadn't formed yet. 0z may have better initialization. 

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40 minutes ago, KingOfTheMountains said:

Pretty clear correlation between the further north members and quicker intensification there. But as Ryan Maue pointed out GEFS is a flawed model and from what I've read it is known for underdispersment and is largely unused by the NHC. I know the EPS is showing underdispersment at 12z but from my understanding it's more rare with that model. And may just be because at 12z the new center hadn't formed yet. 0z may have better initialization. 

GEFS is not as good for intensity. But in this case, both models have the same general path, it's just that the GEFS and GFS are weaker for now. Once we get past the islands.... 😉 

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Here's the Euro at 8 am each day starting Tuesday 9/3. IF this occurred, we would probably have 3-4 days of heavy rainfall over north Georgia. Big IF.

Tuesday 9/3
747538833_euro8am9-3.thumb.png.cfca8fe9249407bea98d5d25876386dc.png

 

Wednesday 9/4
327982428_euro8am9-4.thumb.png.e8649b93cbe2f90d5c24b22f74a98d7f.png

 

Thursday 9/5
1262588994_euro8am9-5.thumb.png.bc7a43afda1f2849910dd4735398139f.png

 

Friday 9/6
596048967_euro8am9-6.thumb.png.36189c3bdf8129354b95a08b5c648e5d.png

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This storm is obviously an SEC football fan and wants to visit as many games as possible - when you say 'four days of heavy rainfall' is there a ballpark of inches?

(I recognize that this is maddening question but at least I didn't ask what time it will arrive in my backyard)

A friend of mine told me that "Atlanta never gets hit by hurricanes" when I moved down here.  

Thanks in advance for keeping us all up to date on this!  

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Old GFS brings support for out to sea at 18z! If only that wasn't a model we've had to put out to pasture because of how bad it is lol. New GFS would be a disaster for the GA coast. 

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