ZCZC MIATCPAT4 ALL TTAA00 KNHC DDHHMM BULLETIN Tropical Storm Isaias Intermediate Advisory Number 30A NWS National Hurricane Center Miami FL AL092020 200 PM EDT Tue Aug 04 2020 ...ISAIAS RACING NORTH-NORTHEASTWARD ACROSS EASTERN PENNSYLVANIA INTO SOUTHEASTERN NEW YORK... ...STRONG GUSTY WINDS...HEAVY RAINFALL...AND THE THREAT OF TORNADOES WILL SPREAD NORTHWARD INTO SOUTHERN NEW ENGLAND... SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION ---------------------------------------------- LOCATION...40.9N 75.1W ABOUT 65 MI...105 KM w OF NEW YORK CITY MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H MINIMUM CENTRAL PRESSURE...994 MB...29.35 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Tropical Storm Warning has been discontinued south of Chincoteague, Virginia, and south of Smith Point in the Chesapeake Bay. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... * North of Chincoteague Virginia to Eastport Maine * Chesapeake Bay north of Smith Point * Tidal Potomac River * Delaware Bay * Long Island and Long Island Sound * Martha's Vineyard, Nantucket, and Block Island A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within the next 12 hours. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 200 PM EDT (1800 UTC), the center of Tropical Storm Isaias was located by NOAA Doppler weather radars and surface observations near latitude 40.9 North, longitude 75.1 West. Isaias is moving toward the north-northeast near 40 mph (65 km/h), and this general motion accompanied by some increase in forward speed is expected through tonight. On the forecast track, the center of Isaias will continue to move near or along the coast of the mid-Atlantic states today, and move across the northeastern United States into southern Canada tonight. Data from Doppler weather radars along with surface observations indicate that maximum sustained winds have decreased to near 65 mph (100 km/h) with higher gusts. Only slow weakening is expected this afternoon, followed by a faster rate of weakening tonight. Isaias is forecast to become post-tropical tonight or early Wednesday. Tropical-storm-force winds extend outward up to 140 miles (220 km) from the center. The New York Harbor Entrance buoy (44065) recently reported a sustained wind of 56 mph (91 km/h) and a gust to 72 mph (117 km/h). The estimated minimum central pressure based on surface observations is 994 mb (29.35 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Isaias can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml. WIND: Widespread tropical-storm conditions are expected in the tropical storm warning area in the mid-Atlantic states and southern New England, including portions of the Chesapeake Bay region today, with wind gusts to hurricane force possible. These winds could cause significant tree damage and power outages. Tropical storm conditions are expected to reach southern New England this afternoon and northern New England tonight. Gale-force winds are expected to spread into southeastern Quebec tonight and Wednesday. See products issued by Environment Canada for more information. RAINFALL: The following rainfall accumulations are expected along and near the track of Isaias: Central and Northern Mid-Atlantic: Additional 2 to 4 inches, isolated maximum storm totals of 8 inches. Eastern New York into Vermont: 2 to 4 inches, isolated maximum totals 6 inches. Western Connecticut, western Massachusetts, New Hampshire and western Maine: 1 to 3 inches. Heavy rainfall along the East Coast, near the path of Isaias, will result in flash and urban flooding, some of which may be significant in the mid-Atlantic and Northeast through tonight. Potentially life-threatening urban flooding remains possible Philadelphia, and elsewhere along and just west of the I-95 corridor today. Scattered minor to moderate river flooding is likely across portions of the Mid-Atlantic. Quick-responding rivers in the Northeast will also be susceptible to minor river flooding. TORNADOES: A few tornadoes are possible across northern New Jersey and southeastern New York, through southern New England, by late afternoon. A risk for tornadoes may continue across northern New England through this evening. SURF: Swells generated by Isaias will spread northward along the mid-Atlantic and Northeast coasts of the United States today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 500 PM EDT. $$ Forecaster Stewart/Roberts NNNN