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Hurricane Dorian (05L)

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INTERESTS IN SOUTHERN AND CENTRAL FLORIDA SHOULD MONITOR THE
PROGRESS OF DORIAN.  WATCHES MAY BE REQUIRED FOR PORTIONS OF THE
EAST COAST OF FLORIDA LATER TODAY.

 

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Saturday, August 31 - 5 AM Update

WTNT45 KNHC 310848
TCDAT5

Hurricane Dorian Discussion Number  28
NWS National Hurricane Center Miami FL       AL052019
500 AM EDT Sat Aug 31 2019

Dorian continues to look impressive in satellite imagery this
morning, with a fairly symmetric area of cold cloud tops surrounding
a 10-15 n mi wide eye
.  There have been no new aircraft data from
the storm since the last advisory
.  However, the satellite
appearance has changed little since the aircraft were last in the
storm, and the various subjective and objective satellite intensity
estimates have changed little over the past several hours.  Based on
this, the initial intensity remains 120 kt.

The initial motion is now 290/10.  A low- to mid-level subtropical
ridge to the north of the hurricane should steer it west-
northwestward to westward for the next 48 h or so, with the forward
speed becoming very slow as the center passes near or over the
Abacos and Grand Bahama
. The track guidance for this part of the
track is tightly clustered, and the new forecast track is near the
ECMWF, UKMET, and HCCA corrected consensus models.  The track
forecast becomes much more problematic after 48 h
.  The global
models the NHC normally uses, along with the regional HWRF and HMON
models, have made another shift to the east to the point where none
of them forecast Dorian to make landfall in Florida
.  However, the
UKMET ensemble mean still brings the hurricane over the Florida
peninsula, as do several GFS and ECMWF ensemble members.  The new
track forecast for 72-120 h will be moved eastward to stay east of
the coast of Florida, and it lies between the old forecast and the
various consensus models.  Additional adjustments to the forecast
track may be necessary later today if current model trends continue
.
It should be noted that the new forecast track does not preclude
Dorian making landfall on the Florida coast, as large portions of
the coast remain in the track cone of uncertainty.  Also,
significant impacts could occur even if the center stays offshore.

Dorian should remain in a generally favorable environment for the
next 3-4 days, and the intensity guidance indicates it will remain
a powerful hurricane during this time.  The new intensity forecast
calls for a little more strengthening today, then it shows a slow
weakening that follows the trend of the intensity guidance.  During
this time, the biggest intensity changes may come from hard-to-
forecast eyewall replacement cycles.  Late in the forecast period,
increased vertical shear and proximity to land is expected to
cause some weakening.


Key Messages:

1. A prolonged period of life-threatening storm surge and
devastating hurricane-force winds are likely in portions of the
northwestern Bahamas, particularly on the Abaco Islands and Grand
Bahama Island
.  A hurricane warning is in effect for these areas,
and residents should listen to advice given by local emergency
officials and have their hurricane preparations completed today.

2. Life-threatening storm surge and devastating hurricane-force
winds are still possible along portions of the Florida east coast
by the early to middle part of next week, but since Dorian is
forecast to slow down and turn northward near the coast, it is too
soon to determine when or where the highest surge and winds will
occur
. Residents should have their hurricane plan in place, know
if they are in a hurricane evacuation zone, and listen to advice
given by local emergency officials.

3. The risk of strong winds and life-threatening storm surge is
increasing along the coasts of Georgia and South Carolina during
the middle of next week
.  Residents in those areas should continue
to monitor the progress of Dorian.

4. Heavy rains, capable of life-threatening flash floods, are
expected over portions of the Bahamas and coastal sections of the
southeastern United States this weekend through much of next week.


FORECAST POSITIONS AND MAX WINDS

INIT  31/0900Z 25.8N  72.6W  120 KT 140 MPH
 12H  31/1800Z 26.1N  74.0W  125 KT 145 MPH
 24H  01/0600Z 26.5N  75.8W  125 KT 145 MPH
 36H  01/1800Z 26.7N  77.2W  125 KT 145 MPH
 48H  02/0600Z 26.9N  78.1W  120 KT 140 MPH

 72H  03/0600Z 27.5N  79.4W  115 KT 130 MPH
 96H  04/0600Z 29.5N  80.5W  110 KT 125 MPH
120H  05/0600Z 32.0N  80.5W   95 KT 110 MPH

085012_5day_cone_no_line_and_wind.png.17c4bd1e613534935d6666a3e5d853a4.png

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Incredible cross-section view of Dorian from the HWRF today at 2 pm. If that's not lungs I don't know what is. 😉 

Something else that is interesting in the image. Notice the black area under the eye. Remember a hurricane is a giant area of low pressure. Because the pressure is so low in the eye, the water below isn't being pressed down as far either. As a matter of fact, the water around and under the eye, is elevated compared to the water around it, hence part of the reason for surge. Think of it as a bubble of water that is traveling with the eye. 

hwrf_Winds_10m_00_018_51256260_cross_weathernerds.thumb.png.b5132bcc22050739cf2bdabcd2dd7052.png

 

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Weatherbell update

Quote

Bottom line,

Track shifted east in relation to FLA but stays similar in the Carolinas

Northern Bahamas devastated while Nassau is missed the swath of the worst of the storm

FLA a near miss but a miss nonetheless. While there is room for it coming further west, it would still stay offshore due to the coast

The shift east in FLA may be followed by a shift west further north, which the Carolina coast raked

Our new track will be issued around 10 am eastern and will reflect these changes

 

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Saturday, August 31, 8 AM Update

BULLETIN
Hurricane Dorian Intermediate Advisory Number 28A
NWS National Hurricane Center Miami FL       AL052019
800 AM EDT Sat Aug 31 2019

...NOAA HURRICANE HUNTER RECONNAISSANCE PLANE FINDS DORIAN STRONGER
AND MOVING WESTWARD...


SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...25.8N 73.0W
ABOUT 445 MI...715 KM E OF WEST PALM BEACH FLORIDA
ABOUT 280 MI...450 KM E OF THE NORTHWESTERN BAHAMAS
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...944 MB...27.88 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for...
* Northwestern Bahamas excluding Andros Island

A Hurricane Watch is in effect for...
* Andros Island

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued
36 hours before the anticipated first occurrence of tropical-storm-
force winds, conditions that make outside preparations difficult or
dangerous.  Preparations to protect life and property should be
rushed to completion.

A Hurricane Watch means that hurricane conditions are possible
within the watch area.  A watch is typically issued 48 hours before
the anticipated first occurrence of tropical-storm-force winds,
conditions that make outside preparations difficult or dangerous.

Interests in southern and central Florida should continue to monitor
the progress of Dorian.  Watches may be required for portions of the
east coast of Florida later today.

For storm information specific to your area, please monitor products
issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 800 AM EDT (1200 UTC), the distinct eye of Hurricane Dorian
was located near latitude 25.8 North, longitude 73.0 West. Dorian is
now moving toward the west near 12 mph (19 km/h).  A slower westward
motion should 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 today, be near or over the
northwestern Bahamas on Sunday, and be near the Florida east coast
late Monday.

Data from a NOAA Hurricane Hunter plane indicate that the maximum
sustained winds have increased to near 145 mph (225 km/h) with
higher gusts.  Dorian is a category 4 hurricane on the Saffir-
Simpson Hurricane Wind Scale.  While some fluctuations in intensity
are possible, but Dorian is expected to remain a powerful hurricane
during the next few days.

Hurricane-force winds extend outward up to 30 miles (45 km) from
the center and tropical-storm-force winds extend outward up to 105
miles (165 km).

The latest minimum central pressure just reported by a NOAA
Hurricane Hunter aircraft was 944 mb (27.88 inches).


HAZARDS AFFECTING LAND
----------------------
WIND:  Hurricane conditions are expected in the hurricane warning
area across the northwestern Bahamas by Sunday, with tropical storm
winds beginning tonight.

STORM SURGE:  A life-threatening storm surge will raise water levels
by as much as 10 to 15 feet above normal tide levels in areas of
onshore winds in the northwestern Bahamas. Near the coast, the surge
will be accompanied by large and destructive waves.

RAINFALL:  Dorian is expected to produce the following rainfall
accumulations this weekend into the middle of next week:

Northwestern Bahamas...10 to 15 inches, isolated 25 inches.
Coastal sections of the southeast United States...6 to 12 inches,
isolated 18 inches.
Central Bahamas...2 to 4 inches, isolated 6 inches.

This rainfall may cause life-threatening flash floods.

SURF:  Swells will begin affect the east-facing shores of the
Bahamas, the Florida east coast, and the southeastern United
States coast during the next few days.  These swells are likely to
cause life-threatening surf and rip current conditions.  Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM EDT.

113611_5day_cone_with_line_and_wind.png.27ebc14113db163dc3701e3fc3b0cfba.png

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