I have been recently perusing the shear tendancy maps over the deep tropics and it seems unsually strange to see such low shear over the deep tropics. Given that it is mid May and ideally not the most condusive to see development in the MDR it seems to support a rather positive atmosphere in the future for cyclogenisis.
Thoughts and individual synopsis are very welcomed.
Lower than normal pressure in the Atlantic.
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CHRISTY
Re: Lower than normal pressure in the Atlantic.
Anthonyl wrote:I have been recently perusing the shear tendancy maps over the deep tropics and it seems unsually strange to see such low shear over the deep tropics. Given that it is mid May and ideally not the most condusive to see development in the MDR it seems to support a rather positive atmosphere in the future for cyclogenisis.
Thoughts and individual synopsis are very welcomed.
you mean we might move into a positive NAO?
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HurricaneHunter914
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CHRISTY
NAO is a large -scale fluctuation in atmospheric pressure in the Atlantic Ocean between the high pressure system near the Azores and the low pressure system near Iceland.The surface pressure drives surface winds and Wintertime Storms from west to east across the North Atlantic affecting climate from New England to Western Europe as far Eastward as Central Siberia and Eastern Mediterranean and Southward to West Africa. NEXT TIME I'LL SPEAK IN FRENCH. 
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HurricaneHunter914
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CHRISTY
lets enjoy these quiet times...cause they might not be around for long time.-
HurricaneHunter914
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One of the most prominent teleconnection patterns in all seasons is the North Atlantic Oscillation (NAO) (Barnston and Livezey 1987). The NOA combines parts of the East-Atlantic and West Atlantic patterns originally identified by Wallace and Gutzler (1981) for the winter season. The NAO consists of a north-south dipole of anomalies, with one center located over Greenland and the other center of opposite sign spanning the central latitudes of the North Atlantic between 35°N and 40°N. The positive phase of the NAO reflects below-normal heights and pressure across the high latitudes of the North Atlantic and above-normal heights and pressure over the central North Atlantic, the eastern United States and western Europe. The negative phase reflects an opposite pattern of height and pressure anomalies over these regions. Both phases of the NAO are associated with basin-wide changes in the intensity and location of the North Atlantic jet stream and storm track, and in large-scale modulations of the normal patterns of zonal and meridional heat and moisture transport (Hurrell 1995), which in turn results in changes in temperature and precipitation patterns often extending from eastern North America to western and central Europe (Walker and Bliss 1932, van Loon and Rogers 1978, Rogers and van Loon 1979).
Strong positive phases of the NAO tend to be associated with above-averagel temperatures in the eastern United States and across northern Europe and below-average temperatures in Greenland and oftentimes across southern Europe and the Middle East. They are also associated with above-average precipitation over northern Europe and Scandinavia in winter, and below-average precipitation over southern and central Europe. Opposite patterns of temperature and precipitation anomalies are typically observed during strong negative phases of the NAO. During particularly prolonged periods dominated by one particular phase of the NAO, anomalous height and temperature patterns are also often seen extending well into central Russia and north-central Siberia.
The NAO exhibits considerable interseasonal and interannual variability, and prolonged periods (several months) of both positive and negative phases of the pattern are common. The wintertime NAO also exhibits significant multi-decadal variability (Hurrell 1995, Chelliah and Bell 2005). For example, the negative phase of the NAO dominated the circulation from the mid-1950's through the 1978/79 winter. During this approximately 24-year interval, there were four prominent periods of at least three years each in which the negative phase was dominant and the positive phase was notably absent. In fact, during the entire period the positive phase was observed in the seasonal mean only three times, and it never appeared in two consecutive years.
An abrupt transition to recurring positive phases of the NAO then occurred during the 1979/80 winter, with the atmosphere remaining locked into this mode through the 1994/95 winter season. During this 15-year interval, a substantial negative phase of the pattern appeared only twice, in the winters of 1984/85 and 1985/ 86. However, November 1995 - February 1996 (NDJF 95/96) was characterized by a return to the strong negative phase of the NAO. Halpert and Bell (1997; their section 3.3) recently documented the conditions accompanying this transition to the negative phase of the NAO.
Strong positive phases of the NAO tend to be associated with above-averagel temperatures in the eastern United States and across northern Europe and below-average temperatures in Greenland and oftentimes across southern Europe and the Middle East. They are also associated with above-average precipitation over northern Europe and Scandinavia in winter, and below-average precipitation over southern and central Europe. Opposite patterns of temperature and precipitation anomalies are typically observed during strong negative phases of the NAO. During particularly prolonged periods dominated by one particular phase of the NAO, anomalous height and temperature patterns are also often seen extending well into central Russia and north-central Siberia.
The NAO exhibits considerable interseasonal and interannual variability, and prolonged periods (several months) of both positive and negative phases of the pattern are common. The wintertime NAO also exhibits significant multi-decadal variability (Hurrell 1995, Chelliah and Bell 2005). For example, the negative phase of the NAO dominated the circulation from the mid-1950's through the 1978/79 winter. During this approximately 24-year interval, there were four prominent periods of at least three years each in which the negative phase was dominant and the positive phase was notably absent. In fact, during the entire period the positive phase was observed in the seasonal mean only three times, and it never appeared in two consecutive years.
An abrupt transition to recurring positive phases of the NAO then occurred during the 1979/80 winter, with the atmosphere remaining locked into this mode through the 1994/95 winter season. During this 15-year interval, a substantial negative phase of the pattern appeared only twice, in the winters of 1984/85 and 1985/ 86. However, November 1995 - February 1996 (NDJF 95/96) was characterized by a return to the strong negative phase of the NAO. Halpert and Bell (1997; their section 3.3) recently documented the conditions accompanying this transition to the negative phase of the NAO.
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Re: Lower than normal pressure in the Atlantic.
Anthonyl wrote:I have been recently perusing the shear tendancy maps over the deep tropics and it seems unsually strange to see such low shear over the deep tropics. Given that it is mid May and ideally not the most condusive to see development in the MDR it seems to support a rather positive atmosphere in the future for cyclogenisis.
Thoughts and individual synopsis are very welcomed.
Can we get back to this discussion?
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hurricanetrack
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I know how a positive or negative NAO effects us here in the US in the winter. During the summer months I have no idea how it effects hurricane season. I have a rough idea that we would want a neg NAO which would cause troughiness in the East keeping the East coast safe due to the trough and vice versa with a pos NAO.
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