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 785 
 WTNT41 KNHC 080856
 TCDAT1
 
 SUBTROPICAL STORM ANA DISCUSSION NUMBER   2
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012015
 500 AM EDT FRI MAY 08 2015
 
 Subtropical Storm Ana has remained convectively challenged
 overnight with only a small cluster of thunderstorms noted revolving
 through the southern semicircle, and only shallow isolated
 convection having recently developed in the inner-core region. The
 initial intensity remains at 40 kt based on previous recon data and
 the lack of any significant change in the overall convective
 pattern since that flight.
 
 The initial motion continues to be a slow drift to the northwest
 or north-northwest at only 1-2 kt. Ana is embedded in a blocking
 pattern that is expected to persist for the next 3 days or so until
 a strong mid-tropospheric low/trough currently located over the
 western U.S. moves into the central and southern Plains and nudges
 Ana northward and eventually northeastward by early next week.
 During the next 48 hours, Ana is expected to move toward the
 southeastern U.S. at a very slow pace. The global and regional
 models are in remarkably good agreement on this weak steering
 pattern persisting through the weekend so, the official forecast
 track is essentially just an update of the previous advisory track
 and lies close to the consensus model TVCA.
 
 Water vapor imagery indicates that a tight mid-/upper-level low has
 finally become juxtaposed with the surface low, and the two have
 remained nearly stationary over the relatively warm waters of the
 Gulf Stream. However, intrusions of dry air into the inner core have
 been noted in satellite imagery and upper-air data during the
 past several hours, which have likely been the main reason for the
 lack of deep convection developing near the center. But with the
 lows now vertically stacked and expected to remain over SSTs of
 at least 25C for the next 24 hours, some slight strengthening is
 expected. Ana could also transition to a tropical storm during
 that time. By 48 hours and beyond, however, Ana's slow movement will
 take the cyclone over colder shelf waters of around 20C-22C, and
 weakening is expected due to the air in the inner core becoming more
 stable. Most of the global models now show Ana remaining a distinct
 entity through the forecast period and accompanied by winds near
 gale force. As a result, the forecast calls for Ana to remain an
 extratropical low on Days 4 and 5. The official intensity forecast
 is similar to the previous advisory and the Decay-SHIPS model.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  08/0900Z 31.6N  77.8W   40 KT  45 MPH
  12H  08/1800Z 31.7N  77.8W   45 KT  50 MPH
  24H  09/0600Z 31.9N  78.0W   45 KT  50 MPH
  36H  09/1800Z 32.2N  78.2W   40 KT  45 MPH
  48H  10/0600Z 32.8N  78.9W   35 KT  40 MPH
  72H  11/0600Z 34.1N  79.3W   30 KT  35 MPH...INLAND
  96H  12/0600Z 37.7N  75.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 120H  13/0600Z 43.0N  65.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Stewart
 
 
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