Tropical Depression Fourteen-E Discussion Number 1

Wiki-Hurricanes Forecast Center

8:00 PM PDT Tue Aug 14 2018

A new tropical depression has formed in the East Pacific. Satellite imagery indicates that the area of disturbed weather located over 1,000 miles southwest of the Baja California Peninsula has become sufficiently organized to earn that designation. Although the low-level circulation is exposed to the west of associated convection, the center is well-defined and the thunderstorms are coalesced into a prominent band as is typical for tropical depressions. Satellite classifications were T1.5/25kt from SAB and T2.0/30kt from TAFB. I agree with the latter agency and set the initial intensity at 30kt accordingly.

Fourteen-E is being steered west, or even a little south of west, by a prominent mid-level ridge over the open Pacific to its north. This motion should continue for the next 72 hours with little deviation. Thereafter, mid-level troughing should develop underneath this ridge and weaken the feature, leading to a turn toward the northwest. The northwest trajectory is likely to continue through the rest of the period, though statistical and dynamical guidance suggests it might not continue long after. Fourteen-E is no immediate threat to land.

Northeasterly shear on the order of 10kt is currently affecting Fourteen-E, and this is why the center has been offset from the convection for most of the day. Model guidance indicates some semblance of this shear should persist for the next 48 hours or so which should keep the intensification rate slow to steady. On days 3 and 4, however, upper-level winds should decrease below 5kt. Combined with ocean temperatures over 27C and mid-level relative humidity values over 65 percent, a more brisk rate of development -- and likely rapid at some point -- should take over. By 120 hours, decreasing ocean temperatures and a slightly drier environment should level off the storm. Out of the reliable guidance, the SHIPS and LGEM are most bullish, depicting peaks of 87kt and 78kt, respectively. The GFS and HWRF show a bonafide Category 1 hurricane, while the HMON and GFS are weaker. Given the environment and known model biases, the initial forecast is above most guidance and calls for Fourteen-E to become a hurricane in 3 days or so, peaking as a Category 2 hurricane on days 4 and 5.


INIT 15/0300Z 30 KT 35 MPH

12H 15/1200Z 35 KT 40 MPH

24H 16/0000Z 40 KT 45 MPH

36H 16/1200Z 45 KT 50 MPH

48H 17/0000Z 50 KT 60 MPH

72H 18/0000Z 65 KT 75 MPH


120H 20/0000Z 95 KT 110 MPH

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