Henri is within 24 hours of landfall now and remains a compact hurricane with significant potential impact, and Grace is poised to regenerate into a new tropical storm in the East Pacific. Lots still going on.
Henri has organized some throughout the day in the warm Gulf Stream off the mid-Atlantic. Pressures have fallen but winds have not risen, remaining a minimal hurricane with a very small hurricane wind field but a large gale swath. Tonight, the system is quite compact, but a very well defined eyewall has closed off with cooler cloud tops and a well defined CDO over the center – quite a bit more of a robust central core than it had this morning with problems closing off cold cloud tops in the eyewall on the north side. Despite this impressive organization, it’s about to move off the Gulf Stream into cooler waters, at which point it will have to rely on baroclinic processes and divergence aloft to maintain intensity, and as such surface winds should begin to weaken a bit. It could either be a minimal hurricane or a strong tropical storm upon landfall, but seems to have reached peak as the best conditions it’s going to get are ongoing. A pretty impressive storm in impressive synoptics, but will be rapidly weakening and losing tropical characteristics over land within 24 hours of now.
The track of the compact center of Henri has actually shifted east just a bit as the storm has remained a little weaker than expected, becoming more steered by lower level winds than those well aloft. This does not change much, but may take the stronger winds a bit closer to eastern Long Island, eastern Connecticut, and Rhode Island than before, when western Long Island was expected to get the brunt of it, with landfall expected tomorrow afternoon. Still, no one under hurricane warnings should let their guard down as this will be a rather significant storm regardless, with widespread potentially historic power outages as the storm slows down and nearly stalls late tomorrow. It will rapidly weaken inland but still carry impact across a large area before finally moving east as the blocking ridge weakens by Tuesday.
Significant impact will occur in the heavily populated corridor from the northern mid-Atlantic to New England. Please refer to the NHC at this link – and local NWS offices – for detailed and specific official local information. Full blog impact statement tomorrow.
Grace was declared a remnant low midday Saturday, losing its closed low level center extremely rapidly over the mountains of Mexico as shown by surface observations. However, the mid and upper level remnants, including the upper air anticyclone, have quickly entered the East Pacific, and this energy has kicked up a large area of vigorous thunderstorms just offshore. This is expected to quickly spawn a new tropical depression or storm in the next 48 hours or so in this basin, just west of Pacific Mexico. If named this would be Marty as the surface center of Linda has dissipated over the rugged terrain and further development would be from a new low level center that builds down from the mid and upper level energy.
Scattered heavy rains associated with the disorganized low level remnants of Grace continue across parts of central Mexico, and the threat of flooding and mudslides remains high for the next day or so. Pay attention to local conditions.
Linda in the Central Pacific regenerated into a tropical storm earlier on Saturday, with a well defined closed LLC shown by ASCAT to have wind well into gale force, and persistent convection. Inexplicably, CPHC maintained it as a remnant low without even a mention on the outlook, much less advisories, but convection is dying off tonight. Waters become warmer the further west Linda goes, which would support continued tropical cyclone maintenance, but shear also increases, so it’s not likely to be a strong or organized system when it reaches Hawaii. Gale warnings are in effect; gusty wind and heavy rains are likely across Hawaii in a few days along with choppy seas.
HNH Weather Notes 
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