131 
 WTNT41 KNHC 140849
 TCDAT1
 
 SUBTROPICAL STORM ALEX DISCUSSION NUMBER   3
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012016
 500 AM AST THU JAN 14 2016
 
 Since the previous advisory, the convective structure of Alex has
 continued to improve with a 15-nmi clear eye now embedded within a
 solid cloud shield of tops colder than -50C, with a ring of cloud
 tops near -60C surrounding the eye in the northern semicircle. The
 intensity of Alex is difficult to ascertain due to its subtropical
 characteristics, and satellite intensity estimates range from
 ST3.5/55 kt from TAFB to a tropical T4.5/77 kt from SAB. NHC AODT
 intensity estimates range from T4.0/65 kt to T4.5/77 kt using a
 tropical pattern and various eye scenes. Since the overall cloud
 pattern of Alex has improved markedly since the earlier 50-kt
 ASCAT-B scatterometer wind data, and a clear and distinct eye
 feature is now evident, the intensity is being raised to 60 kt.
 
 Alex continues to gradually turn toward the left and the initial
 motion is now 020/16 kt.  The cyclone is forecast to turn northward
 during the next 12 hours or so as it is steered by deep southerly
 flow between a large extratropical low centered over the northwest
 Atlantic and a subtropical ridge over northwestern Africa. A general
 northward motion is expected to continue through at least 36 hours,
 which should bring the center of Alex through the central Azores in
 about 30 hours or 1200 UTC 15 January. By 48 hours, Alex should
 start to turn more toward the northwest and west as it moves closer
 to the center of a larger extratropical low forecast to be south of
 Greenland on days 3 and 4. The new forecast track is essentially
 just an update of the previous advisory track through 36 hours, and
 lies close to the consensus model TVCA.
 
 Global and regional models, plus geostationary and microwave
 satellite data, indicate that Alex remains a vertically stacked
 low pressure system up to the 200 mb level, suggesting that the
 cyclone is still primarily a subtropical storm. However, water vapor
 imagery during the past few hours has been hinting that some weak
 upper-level outflow might be trying to develop. GFS and NAM model
 forecast soundings indicate that the current inner-core region of
 Alex with Lifted Indices (LI) of -2 and CAPE values of 400-500 are
 only expected to decrease to LI of -1 and CAPE near 300 as the
 cyclone nears the Azores islands in 24-30 hours. In addition, the
 inner-core region is forecast to remain saturated up to the 200 mb
 level, along with precipitable water values around 1.60 inches. This
 would suggest that Alex could remain as a subtropical cyclone by
 the time it reaches the Azores, and some slight strengthening is
 even possible as 300 mb temperatures are forecast to decrease from
 -40C to around -42C in the inner core. The official intensity has
 been nudged upward and is similar to a blend of the ECMWF and HRWF
 model intensity forecasts.
 
 Gale- and storm-force winds, as well as locally heavy rains, are
 likely to affect portions of the Azores beginning tonight and
 continuing into early Friday. Recent communications with the Azores
 Meteorological Office indicate that wind gusts to a least 70 kt (130
 km/h) are forecast to occur across portions of the central and
 eastern Azores islands. However, stronger gusts will be possible at
 higher elevations, especially over mountain tops and ridges.
 Interests in the Azores should closely monitor the progress of Alex
 and official forecasts issued by the Azores weather office.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  14/0900Z 30.1N  29.3W   60 KT  70 MPH
  12H  14/1800Z 32.4N  28.3W   60 KT  70 MPH
  24H  15/0600Z 36.4N  27.6W   60 KT  70 MPH
  36H  15/1800Z 42.0N  28.2W   60 KT  70 MPH...POST-TROP/EXTRATROP
  48H  16/0600Z 49.1N  29.7W   60 KT  70 MPH...POST-TROP/EXTRATROP
  72H  17/0600Z 60.0N  40.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
  96H  18/0600Z...MERGED WITH EXTRATROPICAL LOW
 
 $$
 Forecaster Stewart