Puna Weather
Tuesday 11th August 2026
Possible hurricane this weekend
Today through early Friday humid with light to moderate easterly trade winds and widely scattered showers.
Late Friday through Sunday possible storm conditions!
By the light of day Invest 93C shows signs of organizing. Models want to strengthen it into a cyclone Wednesday. Since yesterday shear has relaxed significantly, which is allowing a circulation to form.
Models haven't changed much, still showing a near pass or direct hit for windward Hawaii island sometime between late Friday and late Saturday. If the storm is off our northeast shore, we'd be on the weaker winds side. If it's directly over us or to our south we could see the strongest winds.
There are three factors that reduce the risk to us:
1: The storm hasn't matured yet, so if the center reforms to north or south of its current location, the storm would likely pass by us farther to our north or south.
2: There is a vast area of mid-level dry air between the storm and us. If the core isn't completed when it is in this area, dry air would likely wrap into the storm and weaken it or keep it from strengthening.
3: Along the forecasted path there is not much divergence in the upper atmosphere. As the storm pumps air from the surface into the upper atmosphere it starts to pile up and this limits ventilation of the storm, keeping it from reaching its fullest potential.
The factors that increase the risk to us:
1: Models have consistently placed us in the middle of possible outcomes for nearly a dozen runs in a row.
2: Sea surface temperatures under 93C and along its path are exceptionally warm this year, additionally the warm water extends to a great depth, so a stalled storm is not likely to weaken much due to upwelling.
3: Vertical shear is near 0 mph right now and is forecast to remain in the 0 to 10 mph range all the way up to our longitude.
4: Despite the mid-level dry air, the environment is not exceedingly stable with nearly neutral vertical velocity (omega) there's not a lot of bulk subsidence.
I'm posting several models to show that even though they vary, there is a common theme, a storm forms and approaches our island. Something to keep in mind is that the steering flow is between 850mb and 500mb where we see a ridge to our north at all the levels represented (850mb, 700mb, 500mb). The steering flow is from the east-northeast. That means the appearant jog to the north around our island is an artifact of the model's handling of our terrain. The GFS has a 13km grid spacing and the ECMWF has a 9km spacing, whereas both the HAFS-A and the HAFS-B uses a 6km grid for background and a 2km storm-following spacing. Both the HAFS models do not jog north, but show the storm continuing across our island. Therefore we should not be lulled into false confidence.
Once the low forms (probably Wednesday evening) we'll have a better idea of what lies in store. At this point I'm seeing solutions ranging from 995mb to 978mb which is from tropical storm strength to CAT2/3 strength.
