surface, follow in phase with the east-wind component of the surface winds. In advance, or to the east, of the MJO enhanced activity, winds aloft are westerly. In its wake, or to the west of the enhanced rainfall area, winds aloft are easterly. These wind changes aloft are due to the divergence present over the active thunderstorms during the enhanced phase. Its direct influence can be tracked poleward as far as 30 degrees latitude from the equator in both northern and southern hemispheres, propagating outward from its origin near the equator at around 1 degree latitude, or , per day. Irregularities The MJO's movement around the globe can occasionally slow or stall during the Northern Hemisphere summer and early autumn, leading to consistently enhanced rainfall for one side of the globe and consistently depressed rainfall for the other side. This can also happen early in the year. The MJO can also go quiet for a period of time, which leads to non-anomalous storm activity in each region of the globe. Local effects Connection to the monsoon During the Northern Hemisphere summer season the MJO-related effects on the Indian and West African summer monsoon are well documented. MJO-related effects on the North American summer monsoon also occur, though they are relatively weaker. MJO-related impacts on the North American summer precipitation patterns are strongly linked to meridional (i.e. north–south) adjustments of the precipitation pattern in the eastern tropical Pacific. A strong relationship between the leading mode of intraseasonal variability of the North American Monsoon System, the MJO and the points of origin of tropical cyclones is also present. A period of warming sea surface temperatures is found five to ten days prior to a strengthening of MJO-related precipitation across southern Asia. A break in the Asian monsoon, normally during the month of July, has been attributed to the Madden–Julian oscillation after its enhanced phase moves off to the east of the region into the open tropical Pacific Ocean. Influence on tropical cyclogenesis Tropical cyclones occur throughout the boreal warm season (typically May–November) in both the north Pacific and the north Atlantic basins—but any given year has periods of enhanced or suppressed activity within the season. Evidence suggests that the Madden–Julian oscillation modulates this activity (particularly for the strongest storms) by providing a large-scale environment that is favorable (or unfavorable) for development. MJO-related descending motion is not favorable for tropical storm development. However,