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Hurricane BERTHA Forecast Discussion Number 16
2014-08-04 22:42:10| National Hurricane Center (Atlantic)
Issued at 500 PM EDT MON AUG 04 2014 000 WTNT43 KNHC 042042 TCDAT3 HURRICANE BERTHA DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032014 500 PM EDT MON AUG 04 2014 Bertha continues to have a disorganized appearance on satellite imagery. A small burst of deep convection is occurring just east of the center, and the system continues to have well-defined upper-level outflow over the southeastern quadrant. A NOAA Hurricane Hunter aircraft is currently investigating the tropical cyclone, and we shall soon see if Bertha is maintaining hurricane status. Based on wind data from an Air Force mission earlier this afternoon, which showed a slight decrease, the current intensity is reduced to 65 kt. Flight-level wind data from that earlier mission also showed that the circulation had a very small extent over the northwestern quadrant, and high-resolution visible imagery shows low clouds moving northwestward, away from the center, not far from the center over that quadrant. This suggests that, if the environmental low-level flow increases, Bertha may have a difficult time maintaining a closed circulation. For now, the NHC intensity forecast calls for gradual weakening, and is a little below most of the guidance since the shear is predicted to become prohibitively strong, 50 kt or more, in just 36 hours. Fixes from the aircraft showed a gradual increase in forward speed and the initial motion is around 360/15. There are no important changes to the track forecast or reasoning. During the next couple of days, Bertha will be moving between a mid-level high pressure area over the southwestern Atlantic and a broad trough moving off the northeast United States coast. This should result in a gradual turn toward the north-northeast and northeast with additional acceleration during the next 24-48 hours. Later in the forecast period, Bertha or its post-tropical counterpart should accelerate east-northeastward in the mid-latitude westerlies over the north Atlantic. The official forecast is similar to the previous one and lies between the latest GFS and ECMWF tracks. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 29.4N 73.6W 65 KT 75 MPH 12H 05/0600Z 31.8N 72.8W 65 KT 75 MPH 24H 05/1800Z 34.7N 70.7W 65 KT 75 MPH 36H 06/0600Z 37.5N 67.0W 60 KT 70 MPH 48H 06/1800Z 40.0N 62.0W 55 KT 65 MPH 72H 07/1800Z 47.0N 50.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 08/1800Z 49.0N 37.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 09/1800Z 49.0N 24.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch
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