WIND SHEAR AT THIS TIME SEEMS TO BE KEEPING ON THE LID
A gathering of convective rain has slowly evolved in and about the Philippines this week. The area has slowly shifted northward such that it is now centered near northern Luzon Island.
What is working against further organization towards tropical cyclone status is shearing upper-tropospheric winds from the east and northeast.
Japan Meteorological Agency satellite image shows tropical rain gathered off northern Philippines on July 7, 2011.
The latest GFS numerical forecast model (1200 UTC Thursday) shows slow lessening of the (unfavorable) wind shear over the next few days. It also shows the formation of significant low pressure beginning Sunday and Monday east of Taiwan and south of Okinawa.
Movement is forecast to be mostly towards the north as the low gathers together.
LATEST HIGHLIGHT ON THE SUBCONTINENT
Low pressure at the heart of the SW Monsoon circulation is shown by the GFS numerical forecast model to hover over the common area of Gujarat, Madhya Pradesh and Rajasthan for the next few days.
What is more, it is forecast to wring out very heavy falls of rain over a relatively small area during the weekend. Indeed, the "quantitative precipitation forecast" (QPF) of the 1200 UTC Thursday GFS has more than 37 inches (about 95 cm) with 24 hours (July 9-July 10)! The location forecast to have this much rain is 24 degrees North and 75 degrees East, with would be near Mandsaur, M.P.
I do not recall having ever seen this forecast model "show" so much rain in so short a time. I must also say that this is "cyber-weather," NOT an actual forecast. QPF is notoriously unreliable, especially in relation to convective rainfall.
Still, the point is well-taken that a part of western and northwestern India will be at risk of flooding downpours towards the end of the week.
The plum rains are known as "meiyu" in China, the "baiyu" or "tsuyu" in Japan, and the "jangma" in the Koreas. The heart of the plum rain season stretches from early June to mid-July, with a tendency to shift south to north across the affected area.
In the wake of the mid-June cloudbursts, most of Pakistan to northwestern India last week saw a return to dry, hot weather typical of the weeks leading up to the Monsoon onset. It was as if the Monsoon withdrew to its "normal" position for the latter half of June.
The 38.5 degree C (101 degrees F) reading Tuesday in Ajaccio, Corsica, may have been tops in Europe.
Monsoon Onset was June 13th, 2013, in Delhi, almost two weeks earlier than average. The June 15th onset at Karachi and Islamabad was more like three week ahead of schedule.
In Pakistan, hit-or-miss downpours missed the Sindh capital, Karachi. One did hit Pad Idan, where it left 60 mm of rain Wednesday. This was more than 20 times greater than the normal June rainfall.
It is still possible that this scenario is over wrought as to the intensity and spread of rain in Pakistan and northwestern India. However, it is the hunch of the present forecaster that some very unusual weather is going to unfold in the Subcontinent during the next week!