Tropical Storm CRISTOBAL Advisory mié, 27-08

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HURRICANE CRISTOBAL DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042014
1100 PM EDT TUE AUG 26 2014

A NOAA Hurricane Hunter aircraft investigated Cristobal earlier
this evening, and found that the hurricane had strengthened a bit.
Based on SFMR-observed surface winds and dropsonde data from the
aircraft, the intensity was increased to 70 kt.  Since the time of
the aircraft mission, the convective cloud tops have warmed
somewhat -- but this is likely a diurnal fluctuation.  The
dynamical guidance indicates that the vertical shear over Cristobal
will remain modest through about 36 hours, but increase
substantially thereafter.  Therefore the hurricane has a window of
opportunity for strengthening that should last through tomorrow
night.  The official wind speed forecast is close to the latest
intensity model consensus.  Later in the forecast period, as
Cristobal nears and undergoes extratropical transition, strong
baroclinic forcing should result in a powerful post-tropical storm
with hurricane-force winds over the north Atlantic later this week.

Aircraft fixes indicate a northward motion of about 360/13 kt.  The
track forecast philosophy is essentially unchanged from the
previous advisory package.  Over the next day or two, Cristobal
should move through a weakness between 2 subtropical anticyclones.
Thereafter, the cyclone should turn northeastward ahead of a
mid-tropospheric shortwave trough moving off of the northeastern
United States, and accelerate in the mid-latitude westerlies.  The
latest track model guidance has shifted a bit to the left, and the
official forecast remains near the right side of the guidance suite.

FORECAST POSITIONS AND MAX WINDS

INIT  27/0300Z 30.4N  71.5W   70 KT  80 MPH
 12H  27/1200Z 32.0N  71.2W   70 KT  80 MPH
 24H  28/0000Z 34.3N  69.7W   75 KT  85 MPH
 36H  28/1200Z 36.6N  66.5W   75 KT  85 MPH
 48H  29/0000Z 39.5N  60.0W   75 KT  85 MPH
 72H  30/0000Z 47.5N  45.5W   70 KT  80 MPH...POST-TROP/EXTRATROP
 96H  31/0000Z 54.0N  33.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  01/0000Z 62.0N  23.0W   55 KT  65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch