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Hurricane Linda 2021Last Modified: 2021-08-17 15:00 UTCHurricane Linda 2021Linda 2021Linda has not changed much during the past several hours. The system still has characteristics of an annular hurricane with a large circular eye (a little more than 30 nautical miles in diameter) and a ring of deep convection completely surrounding that feature. The convection in the eyewall appears a little less symmetric than it was a few hours ago, however. A blend of the latest Dvorak estimates from TAFB, SAB, and automated values from CIMSS at the University of Wisconsin support nudging the intensity down to 85 mph (75 knots).Even though Linda is over cool 25-26°C waters, research has proven that tropical cyclones that are characterized by an annular cloud pattern usually weaken more slowly than the climatological rate in the eastern Pacific, and we expect Linda to be in that category during the next day or so. Nonetheless, a combination of cool sea surface temperatures and drier air should induce a slow weakening trend. The models suggest that an increase in southerly shear is likely toward the end of the forecast period, and that could assist in the storm becoming post-tropical by then. The NHC intensity forecast lies near the high end of the guidance in the short term and then falls in line with the majority of the guidance from days 3-5.Linda is moving nearly due westward at 265/9 knots. The track forecast reasoning appears fairly straightforward. A mid-level ridge is expected to remain anchored to the north of Linda, which should keep the storm on a westward to west-northwestward track during the next several days. The models are tightly clustered, and only small changes were made to the previous track forecast. Based on this prediction, Linda is expected to cross into the Central Pacific basin in 60-72 hours and be located to the north or northeast of the Hawaiian Islands late this weekend and early next week.Forecaster Cangialosi. Information provided by the National Hurricane Center (NHC).Tropical Storm Henri 2021Last Modified: 2021-08-17 15:00 UTCStorm Henri 2021Henri 2021Henri remains a sheared tropical storm. Geostationary satellite images and microwave data show a relatively large area of deep convection (~200 miles across), but the center of the storm is located near the western edge of the thunderstorms due to ongoing northwesterly vertical wind shear. The latest Dvorak estimates have been steady at 3.0/45 knots from TAFB and SAB, and based on that data, the initial intensity is held at 50 mph (45 knots). The center of Henri is located roughly 130 miles south-southeast of Bermuda currently, and this will likely be as close as the storm gets to the island.The tropical storm is gradually turning to the west, as expected, and the initial motion is estimated to be 255/5 knots. A subtropical ridge over the western Atlantic is building eastward to the north of Henri, and this feature should steer the storm westward at a slightly faster pace during the next two or three days. After that time, the ridge is expected to weaken and shift farther east as a cut off low or negatively-tilted trough develops over the northeast U.S. This change in the steering pattern should cause Henri to turn northeastward between Bermuda and the east coast of the U.S in the 72-120 hours period. The NHC track forecast is a little faster than the previous one in the short term and farther west than the previous one from days 3-5, trending toward the latest consensus models.The northwesterly shear currently affecting Henri is expected to subside later today (August 17), and that should allow the storm to gain strength during the next 12-24 hours. However, a round of moderate northerly shear is expected to setup over Henri during the 24-96 hour period. Although this shear would typically cause some weakening, the combination of warm sea surface temperatures and increasing mid-level moisture could offset the negative influences of the shear. Therefore, no change in strength is predicted beyond the 24 hours period. Some of the models suggest that the shear could lessen again this weekend, so although not explicitly forecast, some strengthening is possible then.Forecaster Cangialosi. Information provided by the National Hurricane Center (NHC).Tropical Storm Grace 2021Last Modified: 2021-08-17 15:00 UTCStorm Grace 2021Grace 2021Heavy rainfall across Haiti, Cuba, Jamaica, the Cayman Islands, and the northern Yucatan Peninsula may lead to flash, urban, and small stream flooding, with the potential for mudslides highest in Haiti and Jamaica.Tropical storm conditions are expected over portions of Jamaica today (August 17), and over the Cayman Islands later today and tonight. Tropical storm conditions are expected over portions of the southern coast of Cuba today in the warning area, spreading westward to possibly other portions of the southern coast of Cuba this evening through Wednesday morning.There is an increasing risk of wind, rainfall, and storm surge impacts on the Yucatan Peninsula of Mexico Wednesday night and Thursday, and a Hurricane Warning will likely be needed for that area later today.The cloud pattern of Grace is gradually becoming better organized on satellite images, but the system still lacks distinct banding features over the eastern semicircle. Cirrus-level outflow from the system appears to be well defined. Flight-level and SFMR-observed surface winds, as well as dropsonde measurements, support an intensity of 50 mph (45 knots) for this advisory.Not much change in intensity is likely through this afternoon (August 17) while the circulation of Grace interacts with the island of Jamaica. Thereafter, since the cyclone will be over the very high heat content waters of the northwestern Caribbean Sea with modestly low vertical shear tonight and Wednesday, strengthening is anticipated. Grace will likely become a hurricane tomorrow and continue to intensify before moving over the Yucatan Peninsula. The interaction with that land mass is expected to temporarily interrupt strengthening, with some reintensification over the Bay of Campeche in 3-4 days. The official intensity forecast is near the model consensus for the first half of the forecast period, but below the consensus for the latter part of the period owing to the inherent uncertainties for that extended time frame.Grace continues to move just a little north of due west, or at about 280/13 knots. A well-defined 500 mb ridge should remain entrenched to the north of the tropical cyclone for the next several days. Therefore, a continued west to west-northwestward track is likely to continue for most, if not all, of the forecast period. The official forecast is close to the previous one through 72 hours and just slightly south of it at 4-5 days. This is very similar to the latest multi-model consensus prediction.Forecaster Pasch. Information provided by the National Hurricane Center (NHC).Tropical Depression Fred 2021Last Modified: 2021-08-17 09:00 UTCDepression Fred 2021Fred 2021Through Tuesday, heavy rainfall may lead to considerable flash, urban, small stream, and isolated river flooding impacts across portions of the Florida Panhandle, southeastern Alabama, and from western Georgia into the southern Appalachians. By the middle of the week, Fred or its remnants will lift northward and impact the central Appalachians and Mid-Atlantic. Landslides are possible across the mountains of North Carolina and Blue Ridge Escarpment on Tuesday.Fred has moved farther inland and is now located near the border of southwestern Georgia and southeastern Alabama. Between 0400-06:00 UTC, Doppler radar data from Tallahassee, Florida, still showed 68-70 knots velocities between 9,000-10,000 ft associated with a solid band of convection in the northeastern quadrant. Using 50% of those values supported keeping Fred as a 35-knot tropical storm at 06:00 UTC. This intensity was also supported by 30-knot winds on the west side of the low-level circulation noted in surface observations. Since that time, however, the solid band of convection has become fragmented and the thunderstorm activity has broken up into more discrete cells. Satellite and radar imagery also indicate that the mid- and upper-level circulations have decoupled and sheared out to the north of the low-level circulation. As a result, Fred has been downgraded to a tropical depression at the 09:00 UTC advisory time. Weakening will continue through today (August 17) as Fred moves farther inland over Georgia and into the southern Appalachians, with Fred likely becoming a remnant low later tonight before merging with a frontal system over the northern Appalachians on Wednesday.Fred has continued to move north-northeastward, or 015/12 knots. For the remainder of today, Fred should maintain a motion toward the north-northeast or northeast accompanied by a gradual increase forward speed owing to a very stable steering pattern between a deep-layer ridge to the east and a broad mid-tropospheric trough to the west. The new NHC track forecast is essentially just an update of the previous advisory track and lies near the middle of the tightly packed NHC model guidance suite.Although Fred is weakening, the system is still expected to bring flooding rains to portions of the southeastern and eastern United States during the next couple of days.This is the last advisory issued by the National Hurricane Center on Fred. Future information on this system can be found in Public Advisories issued by the Weather Prediction Center beginning at 11 AM ED, under AWIPS header TCPAT1, WMO header WTNT31 KWNH, and on the web at http://www.wpc.ncep.noaa.gov.Forecaster Stewart. Information provided by the National Hurricane Center (NHC).