000
WTNT43 KNHC 041439
TCDAT3

HURRICANE BERTHA DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032014
1100 AM EDT MON AUG 04 2014

In spite of its unimpressive appearance on satellite imagery, with
scant evidence of banding features and relatively disorganized deep
convection, aerial reconnaissance data indicate that Bertha has
intensified into a hurricane.  Flight-level, dropsonde, and SFMR
winds from Air Force and NOAA Hurricane Hunter planes support an
intensity of 70 kt for this advisory.  Bertha does have well-defined
anticyclonic upper-level outflow over the eastern and southern
portions of the circulation.  Recent infrared imagery shows warming
cloud tops, so the intensity is probably leveling off.  Dynamical
guidance predicts a very large increase in shear beginning in 24-36
hours, and a weakening trend is forecast to begin around that time.
In about 72 hours, the global models show the cyclone interacting
with a baroclinic zone in the vicinity of Newfoundland, so the NHC
forecast shows Bertha becoming extratropical by that time.

Center fixes from the Hurricane Hunter aircraft indicate that the
motion is now 360/15 kt.  The track forecast remains relatively
straightforward.  Over the next couple of days, Bertha should turn
toward the northeast and accelerate in the flow between a
mid-tropospheric anticyclone over the southwestern Atlantic and a
broad trough moving off the United States east coast.  Later in the
forecast period, the cyclone should continue moving quickly to the
northeast or east-northeast within the mid-latitude westerlies.
The official forecast track is not much different from the previous
one, and close to the dynamical model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 27.6N  73.6W   70 KT  80 MPH
 12H  05/0000Z 30.0N  73.4W   70 KT  80 MPH
 24H  05/1200Z 33.4N  72.1W   70 KT  80 MPH
 36H  06/0000Z 36.3N  69.3W   65 KT  75 MPH
 48H  06/1200Z 39.0N  65.0W   60 KT  70 MPH
 72H  07/1200Z 45.0N  55.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  08/1200Z 49.0N  45.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
120H  09/1200Z 49.0N  33.0W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch