415 words
2 minutes
Hurricane Henriette

Henriette originated from a disturbance behind Hurricane Gil, slowly moving westward while remaining disorganized. By August 3rd, the system would begin showing notable organization, and by the next day, NHC would classify it as a tropical storm. Initially, Henriette had a ragged appearance, with a prominent band of deep convection to its west producing ~40kt winds.

Tropical storm Henriette shortly before its first peak in intensity. Source: cyclonicwx.com
Tropical storm Henriette shortly before its first peak in intensity. Source: cyclonicwx.com

Through the day, Henriette would slowly wrap convection around its center, thus organizing further, reaching its initial 45kt peak before running into cooler waters and beginning a slow weakening process.

Tropical Storm Henriette shown in visible imagery with an ASCAT pass showing 40kt winds overlaid. Source: cyclonicwx.com
Tropical Storm Henriette shown in visible imagery with an ASCAT pass showing 40kt winds overlaid. Source: cyclonicwx.com

Over the next days Henriette would resemble the appearance of a classic dying Eastern Pacific tropical cyclone, with fragile CBs pulsating as it traversed the 26°C isotherm. The storm would end up degenerating into a gale force low as it entered the Central Pacific basin.

Remnants of tropical storm Henriette traversing the open ocean showing almost no convection within the low's center. Source: tropicaltidbits.com
Remnants of tropical storm Henriette traversing the open ocean showing almost no convection within the low's center. Source: tropicaltidbits.com

Contrary to the conventional scenario, a quite particular environmental setup involving an ULL aided the remnants of Henriette, which restarted convective activity despite suboptimal sea surface temperatures, resulting in Henriette getting re-upgraded to a tropical cyclone.

In its second life, the tropical storm found itself in much more permissible conditions, re-strengthening nicely as it moved over gradually warmer waters. Deep convection significantly increased, quickly building a CDO while gravity waves emanated from it’s center. By August 10th, Henriette would meet RI criteria as it gained hurricane status northeast of Hawaii, becoming an anomalous, mesmerizing storm.

Sandwich (VIS + IR) imagery of Hurricane Henriette displaying a well developed eye feature on the evening of August 10th. Source: dapiya.top
Sandwich (VIS + IR) imagery of Hurricane Henriette displaying a well developed eye feature on the evening of August 10th. Source: dapiya.top
True color gif of Henriette northeast of Hawai'i. Source: dapiya.top
True color gif of Henriette northeast of Hawai'i. Source: dapiya.top

Henriette would spend around 42 hours as a hurricane, at first slowly weakening, but as shear sharply increased, Henriette would quickly decouple its low and mid level centers, and then proceed to degenerate a second and last time.

Henriette withering away in the upper latitudes as its low level center becomes exposed. Source: tropicaltidbits.com
Henriette withering away in the upper latitudes as its low level center becomes exposed. Source: tropicaltidbits.com
A microwave pass of Hurricane Henriette during its peak intensity showing minimal banding and a well defined center. Souce: nrlmry.navy.mil
A microwave pass of Hurricane Henriette during its peak intensity showing minimal banding and a well defined center. Souce: nrlmry.navy.mil
Infrared imagery showing the eye of Hurricane Henriette well northwest of the Hawai'ian island chain. Source: cyclonicwx.com
Infrared imagery showing the eye of Hurricane Henriette well northwest of the Hawai'ian island chain. Source: cyclonicwx.com
Hurricane Henriette on the morning of August 11th after its RI phase. Source: cyclonicwx.com
Hurricane Henriette on the morning of August 11th after its RI phase. Source: cyclonicwx.com
Henriette in a highly unusual position for a tropical cyclone. Source: NHC
Henriette in a highly unusual position for a tropical cyclone. Source: NHC