TD 2 Becomes Tropical Storm Bill

842 

WTNT32 KNHC 150237

TCPAT2

BULLETIN

Tropical Storm Bill Advisory Number   3

NWS National Hurricane Center Miami FL       AL022021

1100 PM AST Mon Jun 14 2021

...DEPRESSION STRENGTHENS INTO TROPICAL STORM BILL...

...LIKELY TO BE SHORT-LIVED...

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION

-----------------------------------------------

LOCATION...36.7N 69.8W

ABOUT 335 MI...540 KM ENE OF CAPE HATTERAS NORTH CAROLINA

MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H

PRESENT MOVEMENT...NE OR 55 DEGREES AT 23 MPH...37 KM/H

MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

WATCHES AND WARNINGS

--------------------

There are no coastal watches or warnings in effect.

DISCUSSION AND OUTLOOK

----------------------

At 1100 PM AST (0300 UTC), the center of Tropical Storm Bill was

located near latitude 36.7 North, longitude 69.8 West. Bill is

moving toward the northeast near 23 mph (37 km/h), and this general 

motion is expected through Wednesday with increasing forward speed.

Satellite-derived wind data indicate that the maximum sustained 

winds have increased to near 45 mph (75 km/h) with higher gusts. 

Some additional strengthening is possible on Tuesday, however the 

system is expected to become a post-tropical low and dissipate on 

Wednesday.

Tropical-storm-force winds extend outward up to 70 miles (110 km)

from the center.

The estimated minimum central pressure is 1003 mb (29.62 inches).

HAZARDS AFFECTING LAND

----------------------

None

NEXT ADVISORY

-------------

Next complete advisory at 500 AM AST.

$$

Forecaster Pasch

000

WTNT42 KNHC 150238

TCDAT2

Tropical Storm Bill Discussion Number   3

NWS National Hurricane Center Miami FL       AL022021

1100 PM AST Mon Jun 14 2021

Deep convection has increased in a cluster to the northeast of the 

estimated center.  Scatterometer measurements showed a couple of 

40-41 kt vectors over the southeastern quadrant of the cyclone.  On 

this basis, the estimated intensity is increased to 40 kt, which 

makes this the second tropical storm of the season, albeit a rather 

high-latitude one.  The system is in an environment of fairly 

strong southwesterly shear, but the diffluent upper-level flow has 

apparently contributed to some strengthening in a seemingly hostile 

environment.  Some additional short-term strengthening could occur 

but by 36 hours, the cyclone should merge with a baroclinic zone 

while approaching Newfoundland and become extratropical.  This 

transition is also shown by the FSU cyclone phase analyses of the 

GFS model fields.

Bill is moving fairly swiftly northeastward, or 055/20 kt.  The 

track forecast appears to be straightforward.  The flow ahead of a 

large mid-tropospheric trough near the United States east coast 

should accelerate the system northeastward for the next day or two, 

and until the system dissipates.  The NHC track forecast is similar 

to the previous one and not far from the model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 36.7N  69.8W   40 KT  45 MPH

 12H  15/1200Z 38.9N  65.1W   45 KT  50 MPH

 24H  16/0000Z 42.6N  59.6W   40 KT  45 MPH

 36H  16/1200Z 46.5N  54.5W   35 KT  40 MPH...POST-TROP/EXTRATROP

 48H  17/0000Z...DISSIPATED

$$

Forecaster Pasch