Omega For The Block

A developing and strengthening ridge of high pressure in the Central Atlantic is putting the brakes on the upper level low in the Western Atlantic from moving anywhere anytime soon, with the resulting weather pattern stuck in a rut of dryness...not that anyone will complain about a prolonged dry stretch of weather!   The upcoming pattern, called an omega block because of the Greek letter Omega, typically means weather patterns change little...if any...over a period of days.

You can see the evolution of the high pressure ridge from Tuesday on across the Central portions of the Atlantic.  These strong ridges of high pressure and blocking patterns are rather common at this time of the year -- thanks in part to a weaker jet stream unable to break down ridges of high pressure and also in part to upper level lows that still have some pop in them thanks to lingering chill in the upper atmosphere.   However, the high pressure ridge's strength plus the lack of a "kick" from the jet stream means the upper level low moves little over the coming days.   With the upper low in the Western Atlantic, we are in the confluence of the western side of the low, which means air is generally stable and storm systems that try to move east are shunted southeast around the flow of the upper level low.    While day to day variations may occur, with Tuesday possibly a bit more cloudy than the other days early this week, the next five days will be dry and generally mild.

As we work into late week, the upper low slowly slides east and a second storm system in the Midwest begins to nudge eastward.   This system will move as slow as the upper low in the Western Atlantic -- again, thanks to the strong Central Atlantic high pressure that's preventing much movement.  The fair weather in place for much of this week gives unfortunately to a thunder threat from this Midwest storm system...just in time for the weekend.

The storm system in the Midwest moves little between Friday and Sunday, also stuck in place the last remnants of the upper low in the Western Atlantic spin themselves out just east of Bermuda.   This means off and on thunderstorms will eventually work in -- probably Saturday -- and could last into the early parts of next week, with the potential for a fair bit of rain if this pattern holds.

In any case, the next five days should be rather nice and a great stretch of late Spring weather.