283 
 WTNT43 KNHC 040245
 TCDAT3
 
 TROPICAL STORM BERTHA DISCUSSION NUMBER  13
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032014
 1100 PM EDT SUN AUG 03 2014
 
 Recent satellite and aircraft reconnaissance data indicate that the
 circulation of Bertha has become much better defined this evening.
 The tropical cyclone has also quickly strengthened as convection
 has increased and become organized in a band around the eastern
 portion of the circulation.  An Air Force reconnaissance aircraft
 has measured peak believable SFMR winds of around 55 kt. Although
 the flight-level winds would support a little lower initial
 intensity, a recent dropsonde measured winds in the lowest 150
 meters that also supports an initial wind speed of 55 kt.  The
 aircraft data also indicate that the minimum pressure has fallen to
 around 1007 mb.
 
 The strong northwesterly vertical wind shear that has been affecting
 Bertha is forecast to decrease further during the next 24 hours.
 This should allow for additional strengthening, and the updated NHC
 intensity forecast calls for Bertha to become a hurricane in a day
 or so.  In 36 to 48 hours, strong west-southwesterly upper-level
 winds are forecast to cause a significant increase in vertical
 shear. The shear, along with decreasing sea surface temperatures,
 should cause some weakening before Bertha becomes an extratropical
 low over the North Atlantic in three to four days.
 
 Bertha is moving north-northwest at 15 kt.  The cyclone should turn
 northward and then north-northeastward during the next day or so
 while it moves between a subtropical high to its east and a mid- to
 upper-level trough over the eastern United States.  In a couple of
 days, Bertha is expected to accelerate northeastward and then turn
 east-northeastward when it moves into the mid-latitude westerlies.
 The model guidance is generally in good agreement on this scenario
 through 72 hours, and the new NHC track forecast is similar to the
 previous advisory during that time.  There is increasing spread in
 the track guidance after three days with the ECMWF and UKMET models
 predicting a much faster motion over the North Atlantic than the
 latest GFS.  The four- and five-day forecast positions are close to
 the model consensus and guidance provided by the NOAA Ocean
 Prediction Center.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  04/0300Z 24.9N  73.2W   55 KT  65 MPH
  12H  04/1200Z 27.3N  73.7W   60 KT  70 MPH
  24H  05/0000Z 30.8N  73.4W   65 KT  75 MPH
  36H  05/1200Z 34.1N  72.0W   65 KT  75 MPH
  48H  06/0000Z 36.9N  69.0W   65 KT  75 MPH
  72H  07/0000Z 42.2N  59.5W   60 KT  70 MPH
  96H  08/0000Z 47.5N  50.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 120H  09/0000Z 49.5N  40.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Brown