This morning's overcast skies are very deceptive. While it certainly looks like rain, a quick glance at the upper air sounding shows that the clouds are the result of a temperature inversion keeping a thin layer of saturated air close to the ground. Go up to the Empire State Building's observation deck and the atmosphere is about as dry as can be, and that dryness extends upwards for a couple of miles. The low level cloudiness will stick around all day and keep the afternoon temperature to the low 60s.
So far April has been on the dry side. Only 2.5 inches of rain have been recorded, which is about an inch less than average. That dryness looks to change over the next few days, as the jet stream and a cut-off low duke it out along the East Coast. The upper level low is over Georgia this morning and wants to move up the coast. The zonal jet stream, however, has no time for that nonsense, slowing the low down and allowing lots of moisture to build up in the atmosphere. The end result is a prolonged period of rain starting tonight and lasting through Wednesday morning. Northeasterly winds will keep the temperature steady in the lower 50s all day tomorrow.
The low will get the boot on Wednesday when the jet stream flips from a zonal pattern to a loopy meridional flow with a deep trough out west and a big ridge over the eastern part of the country. The ridging is expected to stick around for a while so get ready for clear skies and highs in the mid 70s on Thursday and Friday, possibly warming to the lower 80s on Saturday.
