813 
 WTPZ44 KNHC 130857
 TCDEP4
 
 TROPICAL STORM CELIA DISCUSSION NUMBER  27
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042016
 200 AM PDT WED JUL 13 2016
 
 While Celia continues to show an eye in infrared imagery, several
 recent microwave overpasses indicate this feature is displaced to
 the north-northeast of the low-level center.  Satellite intensity
 estimates from TAFB and SAB are 65 kt, and a recent CIMSS AMSU
 estimate is 74 kt.  However, a partial ASCAT-B overpass showed
 maximum winds of 55 kt north of the center.  Given these data and
 the level of disorganization implied by the microwave imagery,
 Celia is downgraded to a tropical storm with 60-kt winds.
 
 The initial motion is 300/10.  A mid-level subtropical ridge is
 predicted by the global models to remain to the north of the cyclone
 for the next several days.  This should result in Celia moving
 west-northwestward for the next 36-48 hours.  After that time, the
 guidance becomes somewhat divergent.  The GFS and UKMET models are
 on the south side of the guidance envelope and forecast a more
 westward motion, while the ECMWF is on the north side and forecasts
 a continued west-northwestward motion.  Overall, the consensus
 models have shifted a little to the south after 36 hours.  Based on
 this, the new forecast track is also shifted a little to the south
 and shows a just north of due west motion from 48-120 hours.
 
 Celia should encounter decreasing sea surface temperatures for the
 next 48-72 hours.  After 72 hours, the cyclone is likely to
 encounter strong westerly shear even as it moves over slightly
 warmer water.  This evolution should cause Celia to weaken further,
 with the system forecast to become a tropical depression by 72 hours
 and a remnant low by 120 hours.  The new forecast intensity is an
 update of the previous forecast.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  13/0900Z 18.3N 131.2W   60 KT  70 MPH
  12H  13/1800Z 19.3N 132.7W   55 KT  65 MPH
  24H  14/0600Z 20.4N 134.8W   50 KT  60 MPH
  36H  14/1800Z 21.3N 136.9W   40 KT  45 MPH
  48H  15/0600Z 22.0N 139.0W   35 KT  40 MPH
  72H  16/0600Z 22.5N 144.0W   30 KT  35 MPH
  96H  17/0600Z 23.0N 149.0W   25 KT  30 MPH
 120H  18/0600Z 23.5N 153.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Beven
 
 
 
 052 
 WTPZ45 KNHC 130857
 TCDEP5
 
 TROPICAL STORM DARBY DISCUSSION NUMBER   7
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052016
 300 AM MDT WED JUL 13 2016
 
 Darby continues to strengthen.  The satellite appearance has changed
 from a shear pattern to a central dense overcast, with a larger and
 deeper area of convection than 6 hours ago.  In addition, a WindSat
 37 GHz microwave pass at 0104 UTC showed the development of a
 low-level ring feature.  The initial wind speed is raised to 60
 kt, a bit above the satellite classifications in deference to the
 improved inner-core structure.
 
 Somewhat surprisingly, Darby has been rapidly intensifying during
 the past 24 hours, with a 30-kt wind increase during that time.
 Given the recently observed microwave ring feature and a generally
 conducive environment, it makes sense to be on the high side of the
 guidance in the near-term.  After 24 hours, SSTs should drop to
 around 27C, but the shear is expected to stay low. Thus, the
 forecast intensities are leveled off from days 1-3 in agreement with
 much of the guidance.  A slow decrease in wind speed is predicted at
 long range due to gradually falling SSTs.   The NHC intensity
 forecast is most similar to a consensus of the HWRF, SHIPS and LGEM
 models.
 
 The storm is moving generally westward at about 10 kt.  This
 general motion is expected for the next several days while
 Darby remains on the southern side of a strong ridge over the
 eastern Pacific.  The cyclone could turn toward the west-northwest
 by the end of the period with a weaker ridge possible over the
 western portion of the basin. Only small changes were made to the
 previous forecast, and the latest NHC prediction is on the southern
 side of the well-clustered guidance envelope.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  13/0900Z 15.3N 111.5W   60 KT  70 MPH
  12H  13/1800Z 15.3N 113.1W   70 KT  80 MPH
  24H  14/0600Z 15.5N 115.4W   85 KT 100 MPH
  36H  14/1800Z 15.7N 117.9W   90 KT 105 MPH
  48H  15/0600Z 16.0N 120.2W   90 KT 105 MPH
  72H  16/0600Z 16.7N 124.5W   85 KT 100 MPH
  96H  17/0600Z 17.5N 128.5W   75 KT  85 MPH
 120H  18/0600Z 18.5N 132.5W   65 KT  75 MPH
 
 $$
 Forecaster Blake