Tag Archives: dry slot

NYC Weekend Weather – Apr 19, 2019

Flooding, Rain, Storms, Thunderstorms, Weather Update, Weekend, , , , , , , ,

A slow-moving storm system will impact the area with potentially heavy rain that could trigger flash flooding overnight into the first part of Saturday. Precipitation chances die down significantly with the passage of this round of rain as a dry slot works into the area. However, lingering chances for showers still exist as this storm makes a slow exit to the east. Temperatures during this period are forecast to be at or above normal.

Rest of today – cloudy, but still warm with temperatures rising to about 70°F. We will be in the warm sector with the influence of southerly winds during the day. Rain chances increasing during the evening hours. Steady rain is forecast late into the overnight hours with temperatures. Some of the rain could be heavy. Thunderstorms are also possible, and these would increase the risk of flash flooding. Overnight lows around 60°F.

Weather Prediction Center surface forecast for 8AM Saturday

Saturday – the north-south orientation of the cold front that will provide lift for these storms overnight will align well with the prevailing southerly flow through most of the atmosphere. The slow eastward progression of this front will allow storm cells to train leading to more flooding potential as rain continues Saturday morning. The cold front associated with this slow-moving low should push through by the afternoon. A dry slot should cut off any precipitation for a while during this time frame. High temperatures should be in the low-60s. Overnight lows should fall into the low-50s behind the cold front.

GFS model output of 850 mb winds and relative humidity for 2PM Saturday, notice the pronounced area of browns, indicating very dry air. This is what is referred to as a “dry slot“, which can often follow on the heels of cold fronts associated with mature mid-latitude cyclones.

Sunday – the upper low associated with this storm system is expected to cutoff (become detached from primary westerly steering currents), resulting in a system that will meander and take a long while to exit the region. As such, Sunday is expected to remain cloudy, with a chance for some showers. High temperatures should be similar to Saturday in the low-60s. Overnight lows will again be around the low-50s.

Monday – temperatures warming up into the upper-60s, but yes, that cutoff low still lingers! Chance for showers continues in the morning. Clouds finally decreasing later and overnight lows in the mid-50s.

Nor’easter Update – 12PM, Feb 13, 2014

Noreaster, NYC, Snow, Storms, Weather Update, , , , ,

Satellite water vapor imagery clearly shows an area of drier air (in orange), known as a dry slot, working its way into the nor’easter currently impacting the NYC area. Intense bands of snow continue to push into the interior areas north and west of the city.

However, radar imagery from Mount Holly, NJ NWS office is already beginning to show a break in precipitation associated with this drier air. As this dry air works its way north, we can expect a break with lighter snow/rain for the area. This could work to lower overall snowfall totals in areas that see this break. At the surface, snow has transitioned to rain/sleet for most areas in NYC, Long Island, coastal NJ and southeastern CT. The rain/snow line should remain stable in its current position for the remainder of the afternoon.

Precipitation should transition back to all snow during the evening and overnight. Additional accumulation is expected with more large-scale banding features forecast to form on the backside of the nor’easter low pressure center as it intensifies and exits to the northeast. Another 3-5″ is possible overnight in the city. Snowfall totals in areas north and west should easily top 12″ by the end of this event.

add

Untitled