By: Weatherguy Adonis
Long Wait Now Over As Storm Makes Into Land Earlier Than Expected
Iloilo City, Philippines, 01 April 2012, (0830Z)–Finally, Tropical Storm “02W/PAKHAR” made it to land. The long wait is now over for most of the region weary of the situation so critical for millions of people in Viet Nam who were quite uncertain of their fate as a Tropical system threatened their way of life for the longest time.
The Viet Nam Peoples’ Navy (VPN) has been issuing maritime warnings in the advance of the tropical system for more than 3 days now since the storm has been at very slow pace, resulting to thousands of fishing vessels and maritime activities to a standstill.
Sea-going vessels were being ordered to stay away from the range of the storm, which other ships near the Spratlys archipelago to this day are still anchored due to the cyclonic weather that continues to persist along the East China Sea, closest to the center of where the chaotic seas never fail to persist.
Land Interaction, Weak Inflow
Tropical Storm “02W/PAKHAR,” regained some of its intensity yesterday after reaching a “Diurnal Maximum,” which corresponds to a 24-hour cycle life of a tropical system and especially affected by the easing essential “Inflow” from the North of the South China Sea as the Northeast Monsoon, a.k.a “Amihan,” in the Northern Region of Luzon, Philippines have provided such replenishment of favourable ”Upper-level” push, sending much-needed moisture and momentum the past few days of its existence.
“Outflow” from the Southwestern quadrant of the system has been struggling to provide adequate moisture to fuel the increasingly exhausted source of energy–heat and humidity derived from the “Low-level winds,” that fairly provide constraint as regards to hostile 37-55 km/hr (20-30 kt) “Shearing environment,” which could prove fatal to tropical cyclones.
The Joint Typhoon Warning Center (JTWC) has issued its analysis last night that the central convection that provide adequate banding within its LLCC was fair enough to support the theory that maintaining strength reaching 110 km/hr (60 kt) which average winds was about 101 km/hr (55 kt) along the Southwestern periphery of “02W/PAKHAR,” and “Atmospheric Pressure,” reaching to 988 hPa as indicated on their 1500Z issued bulletin last night, 31 March 2012.
Despite this, and the relatively low “Shearing environment,”our system has continually lost steam, finally succumbed to lower OHC and the lack of good outflow and the existence of a blocking Subtropical Ridge to the Northeast of it, just over mainland China was a conclusive determinant for a true West to West-northwest track towards Southern Viet Nam–this sealed the fate of our system as it starts to dissipate over land as of posting.
Other Weather Systems Along Asia-Pacific
Since the La Niña-enhanced Easterlies have replaced the retreating ”Monsoonal flow,” the source of such energy was snatched from our tropical system off the East China Sea two days ago, thus the weakening state of Tropical Storm “02W/PAKHAR,” and the increasingly hostile oceanographic conditions, which I was referring to as the increasingly cooler “Ocean Heat Content” (OHC) along the coasts of Southern Viet Nam extending to the Northeast to the regions of Hainan Island, China.
Also, a developing return of a moderate surge of the ”Northeast Monsoon” was evident along the Northernmost edges of Northern Taiwan yesterday, this should be closely monitored especially in my country, the Philippines, where the “Wetter-than-normal” conditions generated widespread flooding across the archipelago due to the prevailing influence of the easing “La Niña Event.”
Well-defined LLCC Before Making Landfall
Such ill-effects effected a simmering heat generated temperature along the immediate path of the tropical system, thus a weakening trend has caused a significant loss of ambient conditions for further development. This episode has wrought a disastrous result on the system’s life cycle from which adequate energy source, right variations of atmospheric values and warmer “Ocean Heat Content,” (OHC) are recipe for a perfect environment for tropical cyclones to undergo “Explosive Deepening” (ED) or otherwise known as “Rapid Intensification” (RI).
In the case of our tropical system at bar, there have been lacking variables that has degraded its size in meteorological aspect, which I would refer to its central pressure, diameter, wind intensity and the most important of all is the existence of warm sea surface temperature.
Accelerating Pace Towards Coast, Hits Land
An observation prior to its making landfall today, 01 April 2012, I have been observing that the system has jogged a bit faster on a Westerly to West-northwest trajectory towards Vung Tau, less than 30 km East-southeast of Ho Chi Minh City at around 2032z (432AM-PHL).
The JTWC pegged the system before making landfall at 75 km/hr (40 kt) sustained winds, and gusts reaching 101 km/hr (55 kt), with Central Pressure of 988 hPa, heading generally West at 11 km/hr.
The latest data I have come acrossed this afternoon, at around 0620Z (0220PM-PHL) and 0632z (0232PM-PHL), as evidenced by Vis Sat loop, a well-defined “Eye,” was evident and a “Central Dense Overcast,” where the intense winds along and heaviest rains are present was clearly seen wrapping the “Eyewall,” crashed into shore along the Southeastern coast of Viet Nam near Vung Tau.
Immediately after the advancing Western Quadrant of the system moved past the coast, the ferocity of the winds interacts with land mass, which ultimately cuts the main source of moisture and heat derived from the Sea, and “Land interaction,” would mean winds abruptly makes “Friction” with terrain and “Drier Air Mass,” predominantly present on land, which could also overwhelm the river capacity, and pose a critical threat along the River basins, especially the heavily silted Mekong River system that could result to massive landslides and flash flooding event, not to mention the high surf conditions that could obliterate the coastal communities especially in those highly vulnerable infrastructures that tend to be swept away by strong sea currents and rising tidal surges associated with a “Storm Surge,” or abnormal rising sea levels during an approaching storm along the low-lying coast.
More details later tonight. If you are in Viet Nam and has invaluable data about the storm, please send us your comments and thoughts. We appreciate it but stay safe and keep dry! =)
This has been your Weatherguy hailing from the Philippines, Mabuhay! =)
With data from NOAA, NASA, CIRA, JTWC, JMA, HKO, NRL Mry and Typhoon2000.ph