Taiwan and the southern Japanese islands of Ryukyu are bracing for the impending impact of Typhoon Maria. While reports regarding intensity are varying slightly depending on the reporting agency and timeliness of data analysis, it is largely agreed upon that Maria is still maintaining Typhoon (TY) strength winds, not super typhoon strength winds. The latest public releases from JTWC (Joint Typhoon Warning Center), which is the world recognized authority on all typhoon tracking and forecasting, has TY Maria about 153 miles south/southwest of Kadena AFB in Japan. Storm movement is at 15 knots (17.2 mph), and the track has not been altered significantly in the past 72 hours.
While a number of reports appear to differ on exactly what is happening with TY Maria, it is important to remember that not all agencies use the same criteria for classification. As JTWC is the leader in the field, the scale they work off of would classify a super typhoon as a system that would be the equivalent of a Category 4 storm on the Saffir-Simpson scale. This means that winds have to be at least 130 knots (150 mph) sustained wind speed, with maximum sustained winds measured on one-minute increments, not 10-minute periods like the Japanese Meteorological Agency (JMA) employs. By this standard, Maria has slightly weakened to typhoon strength.
As TY Maria continues on her track, she should begin to weaken as she encounters lower sea surface temperatures and increased wind shear. JTWC explained their track philosophy in their latest prognostic reasoning.
“TY MARIA IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST UNDER THE STEERING STR. AS OUTFLOW WEAKENS AND SSTS CONTINUE TO COOL, THE SYSTEM WILL GRADUALLY WEAKEN AND SHORTLY AFTER TAU 12 AFTER IT MAKES LANDFALL NEAR FOZHOU, CHINA, IT WILL RAPIDLY ERODE AS IT TRACKS ACROSS THE RUGGED INLAND TERRAIN, DISSIPATING BY TAU 48. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.”
The areas that are directly in the path of TY Maria have been evacuated as best as is possible, and most commercial travel to the region has been suspended until TY Maria weakens enough to allow safe passage. What people in the affected areas of TY Maria can expect is moderate to significant structural damage, and possible damage to livestock. Rainfall will be significant. Flooding will be a major issue in some areas, and flash flood and landslide warnings are also in effect for much of the region. Warning updates will be issued by JTWC every six hours until TY Maria has dissipated.