225 
 WTPZ42 KNHC 250832
 TCDEP2
 
 TROPICAL STORM FRANK DISCUSSION NUMBER  15
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072016
 300 AM MDT MON JUL 25 2016
 
 Deep convection associated with Frank has diminished considerably
 since Sunday.  Since the vertical shear over the storm is weak, the
 likely cause for this decrease is the upwelling of cooler ocean
 waters beneath the slow-moving cyclone.  The current intensity
 estimate is reduced to 55 kt in accordance with a Dvorak estimate
 from SAB, and this may be generous.  Since the storm is expected to
 begin moving west-northwestward at a faster forward speed soon, it
 should temporarily pass over a warmer ocean.  Thus some slight
 restrengthening is forecast within the next 24 hours.  After that,
 decreasing SSTs should induce gradual weakening.  Frank is likely
 to be reduced to a remnant low pressure system in 4 days or so, and
 this could occur sooner than that.  The official intensity forecast
 is a blend of the latest SHIPS and LGEM guidance.
 
 Frank had been quasi-stationary over the past several hours,
 although recent images suggest a slightly north-of-west drift
 at about 280/3 kt.  The mid-level subtropical ridge to the north of
 the tropical cyclone collapsed, causing a very weak steering
 current.  However, the global models predict that the ridge to the
 north of Frank will rebuild over the next several days and this
 should produce a west-northwestward motion with some acceleration.
 Late in the forecast period, the shallow remnant low is likely to
 move mostly westward in the low-level flow.  The official forecast
 is a little faster than the previous one and close to the model
 consensus.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  25/0900Z 20.1N 113.2W   55 KT  65 MPH
  12H  25/1800Z 20.3N 114.0W   55 KT  65 MPH
  24H  26/0600Z 20.6N 115.3W   60 KT  70 MPH
  36H  26/1800Z 21.0N 117.0W   55 KT  65 MPH
  48H  27/0600Z 21.6N 118.7W   45 KT  50 MPH
  72H  28/0600Z 23.1N 122.2W   35 KT  40 MPH
  96H  29/0600Z 24.0N 125.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  30/0600Z 24.5N 128.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Pasch