ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM

Hurricane Chris Discussion Number  20
NWS National Hurricane Center Miami FL       AL032018
1100 AM AST Wed Jul 11 2018

The IR signature of Chris has fluctuated substantially this
morning.  The eye became obscured by clouds shortly after sunrise,
and an SSMIS overpass at 1120 UTC indicated that the vortex had
become tilted, with the mid-level eye displaced to the east of the
low-level center of circulation.  Since that time, however, the eye
has once again become more distinct in visible and IR imagery.
Dvorak estimates from all agencies had decreased markedly at 1200
UTC but given the improvement of the cloud pattern since then, the
initial intensity has been lowered only slightly, to 85 kt.

For the next 12 hours or so, the hurricane will be approaching and
crossing the warm waters of the Gulf Stream, and no further
weakening is expected.  In fact it is possible that Chris could even
briefly re-intensify, as shown by some of the intensity guidance,
although this is not explicitly shown in the forecast. Once the
hurricane crosses the northern wall of the Gulf Stream in about 24
hours, all of the dynamical models indicate that Chris will quickly
acquire extratropical characteristics and rapidly weaken while its
wind field becomes more spread out. Given the lower initial
intensity, the new NHC intensity forecast is slightly lower
than the previous one for the first 36 hours, but very similar
thereafter, and is close to a consensus of the global and hurricane
dynamical models.

Almost no change has been made to the track forecast.  Chris should
continue accelerating toward the northeast ahead of an approaching
mid-level trough over the next couple of days.  By 96 hours, all of
the global models forecast that Chris will begin to interact with
another extratropical low, which should cause Chris to slow down,
before the two lows eventually merge by day 5.  The global
models are still in very good agreement on the track of Chris,
especially for the first 72 h of the forecast and confidence
remains high in the track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 36.4N  67.8W   85 KT 100 MPH
 12H  12/0000Z 38.7N  64.6W   85 KT 100 MPH
 24H  12/1200Z 42.7N  59.6W   75 KT  85 MPH
 36H  13/0000Z 46.9N  53.3W   60 KT  70 MPH...POST-TROP/EXTRATROP
 48H  13/1200Z 50.3N  45.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  14/1200Z 56.8N  26.1W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  15/1200Z 62.0N  16.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  16/1200Z...DISSIPATED

$$
Forecaster Zelinsky

NNNN