Tropical Depression Two becomes Tropical Storm Bonnie
Posted by Chris in Tampa on 5/28/2016, 5:06 pm
Track:
http://www.nhc.noaa.gov/refresh/graphics_at2+shtml/203139.shtml?5day#contents

Floater:
http://www.ssd.noaa.gov/PS/TROP/floaters/02L/02L_floater.html





TROPICAL STORM BONNIE ADVISORY NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022016
500 PM EDT SAT MAY 28 2016

...DEPRESSION STRENGTHENS INTO TROPICAL STORM BONNIE...
...LOCALLY HEAVY RAINFALL SPREADING ACROSS COASTAL AREAS OF SOUTH
CAROLINA...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...31.1N 79.4W
ABOUT 120 MI...190 KM SE OF BEAUFORT SOUTH CAROLINA
ABOUT 125 MI...195 KM SSE OF CHARLESTON SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


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

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Savannah River to Little River Inlet South Carolina

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 12 hours.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 PM EDT (2100 UTC), the center of Tropical Storm Bonnie was
located by satellite and NOAA Doppler radars near latitude 31.1
North, longitude 79.4 West. Bonnie is moving toward the northwest
near 10 mph (17 km/h). This general motion, accompanied by a
decrease in forward speed, is expected through this evening and on
Sunday as the system nears the coast within the warning area.

Maximum sustained winds have increased to near 40 mph (65 km/h) with
higher gusts. Some additional strengthening is possible tonight as
Bonnie moves over the warm waters of the Gulf Stream. Gradual
weakening is forecast on Sunday.

Tropical-storm-force winds extend outward up to 60 miles (95 km)
from the center, mainly to the northwest of the center.

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are expected to first reach the
coast within the warning area later tonight or early Sunday.

RAINFALL: Bonnie is expected to produce total rainfall accumulations
of 1 to 3 inches with maximum totals of 5 inches from eastern
South Carolina through southeastern North Carolina.

STORM SURGE: Storm surge inundation of 1 to 2 feet above ground
level is possible within the tropical storm warning area during the
next high tide on Sunday morning.

SURF: Bonnie is expected to produce life-threatening surf and
rip current conditions along portions of the southeastern United
States coast through the weekend. Please consult products from your
local weather office.

TORNADOES: An isolated tornado or two will be possible late tonight
and early Sunday over the immediate coastal region from central
South Carolina through southern North Carolina.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM EDT.
Next complete advisory at 1100 PM EDT.

$$
Forecaster Stewart






TROPICAL STORM BONNIE DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022016
500 PM EDT SAT MAY 28 2016

A 1431Z ASCAT-B overpass indicated two 34-kt wind vectors existed in
the northwest quadrant of the tropical cyclone in a region of deep
convection that was not sampled during the earlier reconnaissance
mission. Convection briefly weakened, but has redeveloped and
persisted in that same part of the storm circulation for the past 5
hours. Furthermore, NOAA Doppler velocity radar data from Charleston
and Jacksonville have indicated winds ranging from 50-55 kt between
15,000 and 20,000 feet in the same area of the 34-kt ASCAT wind
vectors. Based on these data, the depression has been upgraded
to Tropical Storm Bonnie.

The initial motion estimate is 320/09 kt. The exposed low-level
center near the southeastern edge of the deep convective cloud
canopy has been easy to track over the past several hours, and has
essentially been moving along the previous forecast track. The NHC
model guidance remains in good agreement on Bonnie gradually turning
toward the north-northwest as it moves around the west side of a
deep-layer ridge, and moving onshore between Charleston and
Beaufort, South Carolina, in about 18-24 hours. After landfall a
mid-level shortwave trough moving northeastward out of the
Mississippi Valley region is expected to significantly weaken the
ridge, causing the steering to collapse. The result is that Bonnie
is forecast to stall or meander along the coastal region of South
Carolina in 24-36 hours before drifting off to the east or northeast
by 48 hours. The NHC forecast track is similar to the previous
advisory track, and closely follows a blend of GFS and ECMWF models.

Bonnie is currently moving over the axis of warmest Gulf Stream
sea-surface temperatures of 27-28 deg C. Although slightly cooler
shelf water lies ahead of the cyclone, those ocean conditions do
not appear to be sufficient to significantly weaken Bonnie based on
rather vigorous convection that has developed just offshore of
South Carolina today. However, southerly vertical wind shear of at
least 20 kt is expected to prevent any rapid or significant
intensification before landfall. After 24 hours, land interaction
and the aforementioned wind shear should induce slow weakening,
although there could be some convective rain bands over water
producing wind gusts to tropical-storm force until about 48 hours.
The official intensity forecast is similar to the previous advisory
and follows the Decay-SHIPS model.

The primary impact from Bonnie is expected to be locally heavy
rainfall.

FORECAST POSITIONS AND MAX WINDS

INIT  28/2100Z 31.1N  79.4W   35 KT  40 MPH
12H  29/0600Z 31.9N  80.1W   40 KT  45 MPH
24H  29/1800Z 32.8N  80.5W   35 KT  40 MPH...INLAND
36H  30/0600Z 33.2N  80.1W   30 KT  35 MPH...INLAND
48H  30/1800Z 33.5N  79.4W   30 KT  35 MPH...INLAND
72H  31/1800Z 34.5N  77.8W   25 KT  30 MPH...INLAND
96H  01/1800Z 35.0N  76.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  02/1800Z 35.7N  75.3W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Stewart
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