A quiet start to the week
As fog breaks, sun will return with two peaceful days of weather on tap before the pattern turns active to end the week.
The Details:
Today & Tonight: Beyond some early fog, Monday Afternoon will bring ample sunshine and a high temperature in the middle 70s. Winds will be light and northerly. Overnight, clear skies should continue as light northeasterly winds remain. Lows will dip into the low 50s.
Looking Ahead: Tuesday will be partly sunny with a high in the upper 70s. Winds will turn around to the south allowing a bit of humidity to come back as well. Into Wednesday, clouds will build up, which should keep fog to a minimum. Scattered showers and thunderstorms are then in the picture through week's end. Stay in touch with the forecast for Wednesday and Thursday as severe storms are possible. Highs will be in the mid to upper 70s with lows in the mid 60s.
The Science:
Discussion: High pressure will be moving into the Lower Midwest in Monday bringing northerly surface winds and thus dry air advection. Dew points will be down and so will temperatures compared to the weekend. The surface divergence associated with the high will mean clear skies. By Tuesday, the high will slide eastward to reset the return flow. As moisture in the lowest levels increases, some cloud cover may begin to develop. A large and deep cutoff upper level low will park in the Western US on Tuesday allowing deep west-southwesterly flow to take hold of the region. This flow will return ample moisture at all levels and prime the atmosphere for showers and thunderstorms. The Storm Prediction Center is already highlighting a large area, including all of Southeast Louisiana and Southern Mississippi, for the possibility of severe storms on Wednesday and Thursday. All threats are on the table at this point. Moisture and shear figure to be high, instability will be the factor to monitor. Precipitation will unfold in rounds as areas of positive vorticity advection move through the sub-tropical jet stream. All told, over the three day stretch several inches could be possible. There are some timing differences among the models as to when the unsettled pattern wraps up. The GFS ends rain showers as early as Thursday Night, while the ECMWF hold on as late as Saturday Morning. We'll look for better agreement and a "hard off-time" in the coming runs.
--Josh