--South Asia:

The latest monsoon low has left its mark upon the hill crest of western India -- and it was a mighty one. At Mahabaleshwar, daily rainfall amounts were 43 and 49 cm as of Monday. That is 92 cm or 36 inches -- fully 3 feet -- of rain within 48 hours. A "thank you" to Shiraz for the statistics relating to the "water tank" of southern India (the Western Ghats, that is).

Elsewhere, rainfall since the middle of last week reached (as of Monday) nearly 40 cm/16 inches in the area of Goa and Honavar. At Ratnagiri and Mumbay, rainfall was about 25 cm/10 inches. Heavy rain last week hit Hyderabad, Andhra Pradesh, where flooding and house collapse claimed a life as well as property.

Again, the key to the wet weather has been a monsoon low: strong yet not abnormally so. This low has taken a "normal" path westward from the Bay of Bengal over the very heart of India. Here is how things look from India's Kalpana-1 satellite as of Monday evening (IMD):

The axis of the midtropospheric monsoon low has shifted to the western half of India between 20 and 25 degrees north latitude. Widespread clouds with at least scattered thunderstorms have invaded southwestern Rajasthan, western Gujarat and even southern Sindh in neighboring Pakistan.

--Here is an overview with an eye toward the fate of the present monsoon low. It will shift from western India to the northern Arabian Sea within the next two to three days. For most of the subcontinent, this shift will bring a marked lessening of the coverage and intensity of rain by Wednesday. In the meantime, Gujarat, western Rajasthan and much of Sindh will have substantial and locally heavy rain. Rainfall will vary widely as it is wont to do in this climate, so I will not attempt to flesh out any details. But it does look to me as though late Tuesday through late Wednesday will see showers and thunderstorms blow through greater Karachi from east to west. Still could be rain from hit-or-miss thunderstorms Thursday.

--South America:

Last month, Sao Paulo had a record low rainfall (trace) for the month of July. Now, owing to late-week downpours, rainfall for August has reached 74 mm. This is nearly two times the normal August rainfall and nearly as much as normally falls in August-July together. Rio de Janeiro shared in these wetting rains. Thanks to Loepa for the heads-up on this.

Upcoming soaking rains over southern Brazil through this week will hit the states of Santa Catarina and Rio Grande do Sul as dry weather returns to Sao Paulo through Rio Janeiro.

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--South Asia:

In sharp contrast to the storm SW Monsoon, 2007, this year has seen a lack of strong Monsoon lows and true tropical depressions along the favored corridor westward from the northern Bay of Bengal. The Monsoon lows that have happened have tended to be weak, the result being a dearth of rain in areas normally moistened by strong westerly wind linked to Monsoon lows.

Numerical forecasts have been consistent in showing a well-marked Monsoon low for the present link and, as of Saturday, these forecasts have been vindicated. Such a low is present along the Orissa (east) coast as of Saturday evening, local time. As taken from the IMD site, here is a look at satellite imagery:

For the southeastern two-thirds of the Subcontinent, it is the picture of unsettled weather having rather widely spread rain and thunderstorms, some leaving very heavy falls. A short account of severe flooding at Hyderabad, southern India, is here. Rainfall within little more than 24 hours was 8.2 inches/21 cm at one site in Hyderabad and it may have been substantially more locally. Elsewhere, Mumbay got a shot of heavy rain (12 cm, or nearly 5 inches) Friday night into Saturday. From the crest of the nearby Ghats, Shiraz writes that wind and rain have begun whipping Mahabaleshwar.

Look for the mid-tropospheric core of this Monsoon low to track west along and north of the 20th Parallel to the Arabian Sea coast within 48 to 60 hours of 1200 UTC Saturday. Thus, the next two to three days will be unsettled, even downright stormy, over a broad swath over peninsular and near-northern India. Winds will be stronger than usual with strongest winds along the crest of the Western Ghats. Where westerly winds blowing onshore and/or upslope normally favor heavy rain, there will be instances of rainfall between 10 and 16 inches (25 and 40 cm) by Wednesday.

--What about Pakistan? Primary impact from the Monsoon low, given the scenario we are faced with as of 1200 UTC Saturday, should be felt within Sindh, although a marked rise in coverage of thunderstorms will happen north to the Hindu Kush and Himalaya, too.

Best I can say now with the information at hand is that potential is good (between Tuesday and Thursday) for one or more widespread outbreaks of thunderstorms with substantial rainfall over Karachi and Sindh as a whole.

--Far East:

Rains in the wake of TS Kammuri have lingered on into Saturday over southernmost China and nearby Indochina. At Beihai, rainfall rose to nearly 40 cm/16 inches at Beihai. At Lao Cai, Vietnam, rainfall reached 31 cm/12.5 inches as of Saturday night, local time.

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--South Asia:

No outstanding weather was apparent to me based upon what I have seen on our database and satellite imagery. No extreme rainfall and, for far southern India and nearly all of Pakistan, little or no rain.

At the same time, I see satellite imagery showing what likely is the start of an important Monsoon low over the Bay of Bengal. We have not seen many well-marked Monsoon lows of this kind in 2008--and none of the strong lows that cut loose over the Subcontinent with disruptive weather in 2007.

Mid-tropospheric low pressure has been consistently shown this week by numerical forecast models beginning late this week (as of Saturday-Sunday) with a resulting boost in rainfall spread over much of the Subcontinent through the middle of next week. Importantly has been the consistent showing of heavy west coast rain and substantial rainfall over Sindh.

As of the latest (1200 UTC) run of the GFS, the picture is different. Rather than one well-marked low, this latest scenario has multiple, relatively weak centers within a broad west-to-east low pressure trough straddling the 20th Parallel in the mid troposphere. The biggest difference is shown for Sindh, where this latest scenario has relatively little rain early next week.

I am not ready to say that the earlier forecasts of meaningful rain over Sindh will not come true. It is, however, cause to begin rethinking prospects. If this scenario unfolds with little rain over Sindh, it would be a repeat of something that happened early in the summer (late June or early July). In that instance, early numerical forecasts of meaningful rain later gave way to dry forecasts which, in the end, proved to be true.

What remains to be seen this time is whether the "typhoon connection" comes into play. To wit, we had Tropical Storm (not typhoon) Kammuri land over south China Wednesday and, as the rule of thumb goes, it can be expected that some impulse of low pressure should show itself over the Bay of Bengal roughly one week later.

--Far East:

Rainfall within the 24-36 hours ended Thursday evening, local time, was 9.5 inches/24.1 cms at Beihai and 9.3 inches/23.6 cms at Shanchuan Dao (island), southern China. The torrential rain fell in the wake of Tropical Storm Kammuri.

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--East Antarctica:

Violent easterly winds raked a stretch of the Antarctic coast south of Australia Wednesday. At the Casey station, there were long stretches of sustained wind reaching 100-120 kmh, or 55-65 knots Wednesday and Wednesday night, local time. At the time of highest wind, sustained speed was 154 kmh/83 knots and highest gust 180 kmh/97 knots. Temperature hovered between -10 and -8 degrees C, or 14-18 degrees F. Weather observations for Australian Antarctic stations are found on the Australian BOM site.

--Tropical Weather:

Tropical Storm Kammuri has landed over south China southwest of Guangzhou and Hong Kong. As of Wednesday night, the weakening storm is driving westward into Guangxi and the borderland with northern Vietnam.

Gales of Kammuri (at least 65 kmh/35 knots) lashed Macau, where gusts reached 100 kmh/55 knots. Winds neared gale speed at Hong Kong.

--South Asia:

In India, shot of west coast rain amounted to 6.6 inches/17 cms at Ratnagiri and 5.3 inches/13 cms at Mumbai, as of Wednesday. Weak low pressure over the NW Deccan may have been the instigator. Elsewhere on the Subcontinent, the lack of well-marked low pressure made for a lack of widespread heavy rain Wednesday. In Pakistan, coverage of rain was well off from where it has been lately thanks to drying from the north.

--I am hobbled today in my effort to fathom whither the Subcontinent weather owing to incomplete numerical forecast data. I believe that the basic scenario is still thus: a monsoon low gathers over the northern Bay of Bengal Saturday and Sunday before rolling westward over the heart of the Subcontinent early next week. By Tuesday, widespread rain could spread out of Gujarat and western Rajasthan for Sindh, that part of the Subcontinent having the lowest and least dependable rainfall. I do hope to get a better idea as to the soundness of this scenario over next few days.

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--Tropical Weather:

Kammuri is the name of the latest tropical storm to arise over the western north Pacific Basin. As of 1200 UTC, the JTWC pinpointed the center of TS Kammuri (10W) 130 miles/210 kms south-southeast of Hong Kong. The storm itself was drifting toward the west-northwest at 6 knots/11 kmh while packing highest sustained winds of 45 knots/85 kmh.

Northerly winds aloft were shearing Kammuri and restricting a run toward typhoon status. Moreover, the storm's wind field was beginning to interact with the hilly land mass of south China.

Landfall will be happening upon southwestern Guangdong west of Hong Kong late Wednesday into early Thursday, local time. Torrential rain and flooding, more than any destructive wind, will be the likely top storm impact.

--East Asia:

--While still bearing in mind the Far East, I will speak of the rain storm that hit Tokyo Tuesday. Rainfall at one spot in the city was 5.5 inches, or 138 mm, within 24 hours. It seems that steamy tropical air bathing southeastern Japan was tweaked into unloading the cloudburst by a dying cold front.

--What remained Wednesday of the big Asian heat wave was centered over eastern Mongolia, where high temperatures were 100-105 degrees, or 38-41 C. At Underhan, the high of 105 degrees F/40.4 C, was about 30 degrees F above normal.

Farther west, a cold front swept into Xinjiang-Uygur, which put a dramatic end to the big heat wave. At Turpan, where the high Monday was 118 degrees F/47.8 C, it only heated to 97 F/ 35.9 C Tuesday. It even sprinkled light rain.

It was much more raucous at Shisanjiangfang, the saddle in the east-west striking Bogda Shan mountain range. A strong north-south pressure gradient behind the cold front drove sustained winds to at least 60 knots, or 110 kmh, early Wednesday. High temperature of 80 F/27 C compared to Monday's 111 F/44 C. Urumqi, the regional capital, was as hot as 101 F/38 C late last week, but saw only 66 F/19 C Tuesday.

--South Asia:

Rain coverage and intensity has held steady or risen today over far-northern, middle and western India while they have lessened over most of Pakistan. A look at weather analyses shows weak midtropospheric lows whirling over the far north (Punjab) and the northern Deccan of peninsular India.

The setting of relatively weak steering winds and comparatively moderate rainfall over the subcontinent will last another two or three days before substantial shifts become apparent. The shift will be the gathering of a broad monsoon low over the northern Bay of Bengal followed by its westward spread over most of the subcontinent. Late this week, I look for an east-to-west rise in coverage and intensity of rain including heavy falls along and near the west coast. There are still indications of a return to significant, even widespread, rain over southern Pakistan (Karachi and Sindh broadly) Monday to Wednesday.

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