A developing South to SW flow of milder air has moved into the region due to WAA. Low pressure and plenty of GOM Moisture is now effecting parts of the Tennessee Valley and SE States today, as a weak wave of low pressure develops near the Tennessee Valley. This wave of low pressure, and precipitation is now building ahead of a very strong cold front now in the Midwest. As this cold front pushes east and southeast and approaches our area tomorrow, a very mild and moist flow will move NE, ahead of and along this cold front. Rain will begin to move into the areas later this evening and into the overnight, along with mild conditions. Temps tonight will remain in the 50's.
On Saturday we can expect periods of rain, which could be heavy at times during the morning hours. A few thunderstorms can also be expected. A break in the rain is likely near mid-day tomorrow. As the cold front moves through tomorrow night, a nice band of moderate to heavy rain and possible thunderstorms will setup during the late afternoon and evening hours. So overall, I expect, anywhere from .50" to 1.50" with this event later tonight into Saturday Evening. Some areas could see 1.50" to 2.00" in any thunderstorm activity.
The big changes begin on Sunday, as our Cold front sweeps offshore and a strong NW flow of colder air rushes in behind this front. P.Sunny skies with windy conditions(15 to 30 MPH and gusty) and temps in the upper 40's to lower 50's can be expected for Sunday.
Monday 11/17 through Friday 11/21
A cold week with below normal temps will be the rule, as an H5 trough settles in for much of the Eastern CONUS. For the Delaware Valley, this will be the coldest air mass of the season. In addition some flurries and snow showers are likely for later Tuesday into Wednesday, as the LES (Lake effect snow) machine kicks in with strong CAA(Cold Air Advection) on strong NW winds.
On Tuesday and Wednesday, the atmosphere will become especially unstable during the afternoon and early evening hours, due to cold air aloft and increased lapse rates. So I expect some flurries and snow shower along with highs in the low to mid 40's and low's in the Upper 20's to low 30's for both days.
Later Tuesday into Wednesday an area of low pressure will develop off the M/A and New England Coasts. There's some concern of a norlun type trough signature in this setup. This means the low will stretch out and the southern end can extend some light precip further west of the low.
Some models are showing this signature and this could actually pose a threat for some periods of light snow Tuesday night into Wednesday, this from NJ into Coastal New England. This needs to be watched and I'll elaborate more on this possibility as we get closer to this time frame.
Another cold front with a clipper will move through for later Thursday and Friday. Temps will be in the low to mid 40's on Thursday, but drop Highs to the Upper 30's and lower 40's behind the front on Friday ! This will also be associated with some scattered flurries and snow showers, along with blustery conditions.
Have a great weekend !