BLOG: Heavy Downpour Expected Tonight
No changes to the forecast in the short term as clouds have already rolled into the area and the initial band of showers and t-storms are located off to the west and northwest right now, though the bulk of this line will likely pass by to the north of Baltimore over the next few hours.
But, as we move into the evening and overnight hours, we will continue to contend with more showers and t-storms moving across the area. I think the best forcing and lift for t-storms tonight and tomorrow morning will go by just to the north of the region, but with precip. Waters in excess of 2 inches tonight until at least 18z tomorrow. There is plenty of moisture or juice for the atmosphere to work with out ahead of the slow moving front, so locally, heavy downpours remain a threat tonight into at least tomorrow morning or midday.
By late tomorrow, the threat for showers and storms should begin to shift off to the east as the front pushes through and some drier air in the mid levels begins to advect in aloft as the upper flow turns more northwesterly and precipitation water values start to lower tomorrow afternoon as well, a sign that at least slightly drier air is working into the atmosphere.
So, while we can still see some t-storms around tomorrow afternoon and early evening, it may not be as widespread or intense as the coverage we may see tonight or tomorrow morning.
With more sun and a downsloping west-northwest flow on Monday, we return to hotter temperatures and it will be rather humid as well (although not quite as humid as Sunday). Monday is most likely dry the first half of the day but then the next frontal boundary and shortwave moves through later Monday and Monday night, giving us another chance for a shower/t-storm. But activity should not be as widespread as what we see tonight or tomorrow, and there will not be as many heavy downpours either as precipitation waters are not nearly as high (they stay under 2 inches Monday afternoon and evening).
Tuesday should be dry as the upper shortwave and surface low rotate up into southern New England off to our northeast.
Then the next piece of energy in this unsettled pattern goes by to our north on Wednesday as disturbances continue to rotate counterclockwise through the region around the broad upper low in eastern Canada. This could set off another shower or t-storm around on Wednesday before we see another break in the action and some drying on Thursday. We may finally get more of a push of low level dry air on Thursday as well, allowing dewpts. and humidity levels to come down.
But until then, it looks like an unsettled and muggy pattern with numerous shower and t-storm chances.
Have a good afternoon!