000
WTPZ42 KNHC 252037
TCDEP2

TROPICAL STORM FRANK DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072016
300 PM MDT MON JUL 25 2016

Frank has been a challenge to analyze today, with lots of
conflicting data.  On the one hand, earlier microwave data showed a
mid-level eye feature, causing the CIMSS-ADT value to shoot up to
hurricane strength.  On the other hand, the overall appearance of
Frank has deteriorated since yesterday in both the organization and
strength of its associated convection.  A partial ASCAT pass also
indicated winds of only about 35 kt, although it missed the full
eastern semicircle.  The ADT value looks much too high, and the
initial wind speed is set to 45 kt, between the 35 kt estimate from
SAB and the 55 kt one from TAFB.

Little change is expected with Frank for the next day or so until
it crosses the 26 deg C isotherm, which will likely cause gradual
weakening thereafter.  Remnant low status is expected in 2 to 3
days when the storm moves over cool water.  Intensity guidance has
dropped since this morning, and the latest NHC prediction reflects
this trend, on the low side of the intensity consensus.

The initial motion estimate remains 280/5.  The subtropical ridge
should strengthen over the next couple of days, which should steer
the storm west-northwestward with some increase in forward speed.
The only significant disagreement in the model guidance, similar to
yesterday, is late in the forecast period regarding the handling of
the shallow remnant low.   The model consensus has done a very good
job of smoothing through these differences with the low, and the
official forecast is close to that aid and the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  25/2100Z 20.6N 114.4W   45 KT  50 MPH
 12H  26/0600Z 20.9N 115.4W   45 KT  50 MPH
 24H  26/1800Z 21.3N 117.0W   45 KT  50 MPH
 36H  27/0600Z 21.9N 118.8W   40 KT  45 MPH
 48H  27/1800Z 22.7N 120.6W   35 KT  40 MPH
 72H  28/1800Z 23.8N 123.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  29/1800Z 24.5N 126.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  30/1800Z...DISSIPATED

$$
Forecaster Blake