Area Forecast Discussion National Weather Service Mount Holly NJ 945 AM EDT Mon Mar 13 2023 .SYNOPSIS... A complex coastal storm will affect the area today through Tuesday night. High pressure then builds into the region Wednesday through Thursday. A cold front approaches on Friday and passes through on Saturday. High pressure returns on Sunday. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... Surface low pressure off the North carolina coast this morning will slowly deepen while moving N/NE today. Rains associated with it have already overspread most of the CWA with the exception being Berks county and wrn Chester county PA. Adjustments to pops and wx have been performed for the mid- morning update. For the southern Poconos, temperatures will be colder with (near freezing this morning). These temperatures will be cold enough for snow at the onset. The highest elevations will likely receive 1-4 inches of snow by midday Monday. By this point, temps will start creeping up into the mid 30s as easterly flow brings in warmer air, and with the coverage of advisory level snow expected to be confined to the highest elevations, continued with the decision to not issue an advisory for this early portion of the event. && .SHORT TERM /7 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... A strong area of low pressure will be east of the Virginia/North Carolina border this evening, as a secondary low lifts along the New Jersey shore just offshore, and this low will lift towards western Long Island by daybreak Tuesday. Most of the region will be in the warm sector for most of the rain for most of the night, though temperatures in the southern Poconos, especially in the higher elevations of Monroe county, will be cold enough to support all snow. With low pressure beginning to take on a more northeasterly track as it lifts towards western Long Island, cold air advection will develop as winds shift to the north. The rain/snow line will then spread south through the Lehigh Valley and most of northern New Jersey, mainly north of the I-78 corridor, and accumulating snow will develop during this time. Snow then continues to spread south Tuesday morning. The main question is how far south snow will get. Think there may be some light accumulating snow as far south as the Philadelphia metro area and into southern New Jersey, but really not expecting much more than an inch or so from around I-195 south. The primary low over the western Atlantic will lift towards eastern New England Tuesday morning, and then this low will merge with the aforementioned secondary low. Precip continues to wrap around this system into the southern Poconos and northern New Jersey into Tuesday afternoon before ending Tuesday evening. Strong shortwave energy will pass through the region Tuesday night, keeping light accumulating snow, mainly over the northern zones. In terms of snow totals, generally expecting 1 to 2 feet of snow across Carbon, Monroe, and Sussex (NJ) counties, though the highest snow amounts will be in the higher elevations, and most areas will pick up about 1 foot or so from tonight through Tuesday. From 6 to 10 inches of snow is possible down to the I-78 corridor, mainly from early Tuesday morning through Tuesday. Will go ahead and convert the Winter Storm Watch to a Winter Storm Warning for Carbon, Monroe, and Sussex (NJ) counties, and will also go ahead and add Warren and Morris counties, as the heavier bands of accumulating snow look to spread a bit farther south. The heaviest snow in Morris county will be in the western half of the county, and snow amounts may be minimal across the eastern half of Morris county. For now, do not think Winter Weather Advisories are needed elsewhere. A tight pressure gradient develops over the area between the low and high pressure building in from the west on Tuesday and Tuesday night. However, latest runs of the models seem to have the low a touch farther east, so the gradient is not quite as strong as it looked in prior runs. As a result, expecting northwest winds 20 to 30 mph with 35 to 45 mph gusts, which are just below Wind Advisory criteria. Although a Wind Advisory may end up being needed for the coastal strips, will hold off one one with this package.
