International Weather Blog
Jim Andrews [Bio] [Email Me]
Monday, October 26, 2009 11:38 AM
Subcontinent Looking for NE Monsoon

--Sorry, everyone, for my absence from this column. I have been otherwise occupied. I see I have missed out on a lot of comments. Some of them a bit wild. I would hope that it would not be personal.

--Questioners have asked as to the North East Monsoon--or lack thereof. October should be the time of rising pressure over the Subcontinent, more so to the north, the outcome being a reversal of winds over peninsular India. During and following this reversal, there comes a time of heightened rainfall over southeastern India to eastern Sri Lanka; it usually lasts well into December.

For whatever reason (I cannot cite any fundamental cause, only symptomatic signs) the NE Monsoon has been weak with little rainfall. As of Oct. 26, rainfall at Chennai was a mere fraction of a millimeter, whereas more than 20 cm should have already fallen, based upon historical data. A full month of rainfall would be about 27 cm.

Moreover, it has been a hot month--more than 2 degrees C above normal so far. Most of the Subcontinent has been warmer than normal, too--more so towards the northwest.

Whatever the underlying cause for the dearth of rain driven by the NE Monsoon, it would seem that meaningful rain lies "right around the corner" with rainy outbreaks as early as Tuesday. I see that the GFS numerical forecast is showing a fairly steady northeasterly surface wind over the Bay of Bengal--a hopeful sign in and of itself.

Anyways, the GFS "QPF" (quantitative precipitation forecast) shows meaningful rain on most days through at least the first of next week. Also, some kind of cyclonic whirl is forecast to ripple westward along the Inter Tropical Convergence to Tamil Nadu and Sri Lanka. This would tend to dry the coast ahead of it then bring some heavy falls of rain upon reaching land--were it to happen.

--Lupit, the former Super Typhoon, has nearly transformed into an extra-tropical storm in skirting southeastern Japan on Monday. Lupit will end up over far-northeastern Asia--maybe Chukotka--late in the week.

The soaking, windswept rain that pelted Greater Tokyo was anything but tropical in feel as the temperature slipped below the 15-degree mark late in the day. Lupit had simply strayed out of its natural environment and, rather than dissipating, began taking advantage of the north-south thermal gradient that normally powers mid-latitude (extra-tropical) storms.

--Another tropical storm has taken shape. And it is one that bears watching for the Philippines. Tropical Storm 23W will soon be sweeping through the southern Mariana Islands (Guam, Saipan). From there, it looks to be a westerly path over the open Philippine Sea with typhoon status at midweek. This storm could reach the Philippines from the east at the weekend.


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Monday, October 12, 2009 1:06 PM
Legacy of Parma

--Parma is nearing its end. As of 1200 UTC on Monday, Oct 10, this tropical storm was swirling over Hainan Dao aimed for the Gulf of Tonkin and eventual last landfall, this time upon northern Vietnam. Parma will leave behind a dramatic legacy, mostly out of northern Philippines, which bore the brunt of three landfalls.

Parma began as a tropical storm during the last days of September. As it spun away from Yap Islands, Parma wrapped into a super typhoon with winds of Category 4 intensity by the start of October. Shortly thereafter, Typhoon Parma still packed a devastating punch as its eye crossed northeastern Luzon Island.

Had Parma simply kept on tracking toward the north and west, it would have been yet another strong, destructive storm to strike the most cyclone-prone nation on Earth. There were the usual flooding rains along with destructive winds. However, thanks to interaction with the even mightier Typhoon Melor, which was working its way towards Japan, a much weakened, downgraded Parma stalled and then backed southeastward, landing once again in northern Luzon. Flooding rains, though not severe winds, returned to the area.

Parma actually slipped off northeastern Luzon long enough to claim a third landfall at about the middle of last week. Then, at last, Parma drifted westward to the South China Sea and away from Luzon on Friday.

In its wake it left more than two meters of rain (about 87 inches, by my best reckoning) over the highland city of Baguio. Half of this fell within about 30 hours ended on Friday, local time. Near to west shore of Luzon, Parma also left about one meter of rain at Vigan with nearly as much striking nearby Laoag City. And Parma dealt out half a meter of rain in Dagupan.

The above are merely climatological statistics; cold hard numbers. But the cloudbursts of rain that they bespeak unleashed devastating floods and suffering for many, many people.

--Things have really quietened over the Subcontinent now that the abortive tropical cyclone has long since died out. A segment of the Westerlies has taken hold far to the north and has flushed the northwestern half of the Subcontinent with dry air. The IMD have adjusted the line of Monsoon withdrawal well southward, albeit still short of the average alignment for the time of year.


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Wednesday, October 07, 2009 10:37 AM
Melor Bears Down on Japan

Image credit: Navy Research Lab Monterey -- NRLMRY

--Typhoon Melor in making its last dash for southern Japan. Latest word from the JTWC has Melor ranked as a Category 1 storm; however, the JMA still have Category 2 status for the typhoon.

It is clear to me that transformation from true tropical to extra tropical in nature on the part of Melor has begun based upon the asymmetry of its cloud shield. Moreover, surface air temperature and dew point over southern Japan is too low to qualify as tropical.

At the time of the above satellite shot (Wednesday night, local time), the storm center was plotted directly south of the Kii Peninsula on southernmost Honshu Island. Latest JTWC and JMA movement was northeastward at 25 knots/45 kph. Meaning that landfall over southern Honshu will happen within a few hours after this posting.

The relative coolness of air over Japan suggests to me than Melor will track somewhat to the right of that indicated by the aforesaid agencies, but I believe more likely north and west of Tokyo. The answer will be known within several hours, one way or another.

This storm is going to pour 10-20 cm of rain over much of Japan, the far southwest and far north being the primary exceptions. Amounts above 30 cm, maybe even 50 cm, will happen in southern Honshu. The area of Owase on the southeast-facing Kii Peninsula is ideally located for extreme falls of rain in storms like Melor.

Melor will sweep out to sea east of northern Honshu as a tropical storm during Thursday afternoon and evening, local time.

--Tropical Storm Parma has become stuck, all-but dead in the water in and about northern Luzon Island, Philippines. The latest plot of Parma's center had it a bit east of Iligan Point. Weak steering winds that have virtually becalmed Parma will keep it parked in the area of northern Luzon for another day or two.

The latest on Parma has it a minimal tropical storm with 35-knot/65-kph highest sustained winds. Owing to proximity to rugged northern Luzon, Parma is bound to weaken further and lose, at least temporarily, tropical storm status.

-Whether storm or depression, Parma will pose further serious flood threat to northern Luzon, the northwest most of all. This area has seen widespread 30-90 cm falls of rain owing to Parma. At Baguio, 36-hour rainfall ended Wednesday evening, local time, was near 40 cm. Thus, Parma's output in the highland city has reached one meter, or 40 inches.

-Numerical forecast models still show Parma leaving to the west of northern Luzon late in the week. Its forecast track over the open South China Sea could see a return to tropical storm status ahead of a landfall upon south China.


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Tuesday, October 06, 2009 12:15 PM
Latest on Melor and Parma

(Image Credit: Joint Typhoon Warning Center)

--Typhoon Melor has weakened significantly during the last 24 hours, since the last writing of this web log. Yet, at 110 knots, highest sustained winds (JTWC, as of 1200 UTC, Tuesday) still ranked Melor near the top end of Category 3 status. Melor has nearly veered into a northerly direction east-southeast of Okinawa. Further veering during the next 24 hours will bring the storm track in line with the south shore of mainland Japan. At this time, the odds seem to favor the broad Kii Peninsula of southern Honshu, or south of Osaka.

-Numerical forecast tracks along with that of the JTWC have been adjusted westward such that the forecast path lies well to the north and west of Tokyo. If on the mark, this latest scenario bodes ill for greater Osaka (Kansai) as well as Nagoya, another major city between Tokyo and Osaka.

-Storm strength at landfall could be Category 2 -- a potentially destructive storm. Rainfall, even with the accelerating motion forecast for Melor, will reach between 20 and 40 cm in hard-hit areas. This would imply serious flooding and mudslides on this mountainous archipelago.

As for Tokyo, a track to the north and west spares it the worst rain as well as wind.

(Image Credit: Navy Research Lab Monterey)

--Parma has returned to the Philippines. In other words, the center of Tropical Storm Parma has landed over the northwestern corner of Luzon (as of 1200 UTC, Tuesday). Weak, variable steering winds have all but calmed Parma, so it will loiter in the area of northern Luzon for another two to three days. During this time, more excessive rain (another 30-60 cm) will pound northwestern Luzon (Baguio to Laoag City, where 60-90 cm has already fallen owing to Parma). This is a setup for major, long-lasting flooding.


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Monday, October 05, 2009 12:44 PM
No Arabian Sea Cyclone, But Watch Melor and Parma

--This is no news flash to anyone following the story of a would-be Arabian Sea cyclone. It became clear late last week that this was not going to happen. It took some time for the foremost cause of this none-happening to show. The culprit? A "Western Disturbance," which is another name for a short-wave trough in the westerlies. Anyways, this western disturbance was not indicated at the time that numerical forecast were showing a tropical cyclone (low) off western India., which is consistent inasmuch as the northern system (of the strength it happened to be) would be expected to preclude a tropical cyclone over the northern Arabian Sea.

The western disturbance that blocked any Arabian Sea cyclone dipped out of Afghanistan and into Pakistan during the weekend. In so doing, it set up southerly steering wind flow over much of the Subcontinent. Enter a tropical wave drifting west from the Bay of Bengal. The shift to southerly steering winds veering this wave northward along a path to the east of the Western Ghats.

Ironically, the western disturbance was the spark for rain in Pakistan rather than any tropical low, but the rain happened far to the north as thunderstorms along the northern edge of the plains. As had been forecast, offshore wind flow and blazing sun put Karachi on the "hot plate" with four-straight, 100-degree days. Hottest were Friday (107 F/41.8 C) and Saturday (106 F/40 C).

-Rain-wise, India did well by this tropical weather system. Indeed, "too well" in areas of Karnataka that were swept by major flooding unleashed by its rain. There was an unbroken swath of heavy to very heavy rain across the mid-south of India, especially over Andhra Pradesh and Karnataka into Maharshtra. Kurnool, Andhra, was hit hard.

Now, with the tropical wave winging northward for the Himalaya, Mumbai has picked up 16 cm of rain within 48 hours. All of October has had, on average, only about 6 cm. Also doused during the last few days have been areas of Madhya and Uttar (14 cm at Agra).

-Looking forward, the word for the Subcontinent is that "it is not over" -- yet. The tropical wave is slowly tracking towards the north and the northeast. The steamy tropical settle that surrounds the wave (still a part of the SW Monsoon, I would say) will help to instigate further local heavy to very heavy falls between north-central India and the middle and eastern foothills. The last of the heavy rain will fall along the eastern foothills late in the week.


(NRLMRY image)

--Typhoon Parma struck storm-weary Luzon Island late last week. Landfall was over the northeast, where wind damage was severe. However, I believe that highest rainfall has happened over the northwest of the island: Laoag City, Vigan and even as far south as the highland city of Baguio. Best that I can tell, based upon our database here at AccuWeather.com, rainfall has topped 80 cm at Laoag with nearly 70 cm pelting Vigan. Both Vigan and Baguio claimed 50-cm falls of rain during their respective wettest 24-hour spans.

-Trouble with Parma (as of 1800 UTC, Monday, a strong tropical storm roughly between Luzon and Taiwan) is that it is stuck in a region of light steering winds. Which means that it will spin for a few days off northern Luzon (or maybe southern Taiwan) unleashing even more extremely heavy rainfall. It was a typhoon last summer that unloaded about 2.5 meters of rain upon some highland site in Taiwan. Parma could potentially double the rain amounts already received over northwestern Luzon.


(JTWC image)

--Melor has been a dramatic super typhoon over the open Philippine Sea following its crossing of the Mariana Islands late last week. Anatahan, the whole island a volcano, took a direct hit from Melor.

-Melor will veer northward and northeastward east of the Ryukyu Islands (Okinawa among them) on Tuesday and Wednesday. It will then track over, or barely south of, the southern Japan mainland on late Wednesday to Thursday. Looks as though it will still be a typhoon, albeit a weakening one. This also looks like a potentially devastating storm wielding torrential, flooding rain and destructive wind. A cold front settling southward into the path of the typhoon will work to shunt its path eastwards while also greatly bolstering rainfall to its north.


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