(Premium) Heavy rain, gusty winds possible this weekend

Forecast models have come into better agreement on the eventual evolution of a low pressure system, which will track from the Mississippi Valley into the Northeastern United States this weekend. Setting the stage for the surface low pressure development will be a mid level atmospheric disturbance, which will eject from the Southwestern United States into the Central United States during the latter half of this current work week. In our area, mid level heights will rise (and temperatures will moderate) ahead of its approach.

Eventually, by Saturday, moisture is expected to stream toward our area as a result of increased southerly winds and a developing low level jet. Initial concerns develop as forecast models show a stout low level cold air signal at the surface, but warming air aloft. This may cause the development of some light frozen precipitation initially in the suburbs or interior. The main hazardous weather threat will come later on Sunday, however, once a significant low pressure system develops into the Great Lakes. A strong low level jet and forcing is likely to bring the potential for heavy rain, as well as gusty winds.

Frozen Precipitation | Threat: Slight

Overall, the threat for wintry precipitation with this storm system is very low. The antecedent airmass is quite poor for snowfall or winter weather. The atmospheric evolution, additionally, is highly unfavorable for frozen precipitation. That being said, as moisture from the incoming storm system starts to increase, forecast models do show a low level cold wedge near the surface. This causes some concern for icing or light frozen precipitation in the interior and higher elevations for a period of time on Saturday Night and Sunday morning.

GFS model showing the potential for frozen precipitation on Saturday evening across the interior.

GFS model showing the potential for frozen precipitation on Saturday evening across the interior.

This threat will be highest — and very localized — to the interior areas of New Jersey, New York State, and Connecticut on Saturday Night and Sunday morning. Frozen precipitation is not anticipated near the coast or in the NYC Metro Area. That being said, interior locations should be aware of the potential for icy/slippery roads for a few hours during the aforementioned time frame. We will continue to monitor forecast models over the next few days as well as their handling of low level cold air.

Heavy Rain | Threat: Moderate

As a low pressure system drives toward the Great Lakes, moisture will surge northward on Saturday and Sunday. A warm front associated with the storm system will move through during Saturday Night — and a strong low level jet is expected to surge toward the area on Sunday morning. With enhanced lift for precipitation will come the threat of very heavy rain in a brief period of time on Sunday.

This rain looks to be relatively focused near the frontal boundary(s) associated with the storm system. Forecast models indicate the potential for upwards of 1″ of rain in a 6-10 hour period as the storm system moves through on Sunday, with heavy precipitation rates. This will obviously include the potential for localized flooding in poor drainage/low lying and urban areas.

Forecast models show the potential for upwards of 1" of rain in parts of the area through Sunday.

Forecast models show the potential for upwards of 1″ of rain in parts of the area through Sunday.

Gusty Winds | Threat: Slight

With the strong low pressure system, both aloft and at the surface, will come a strong low level jet. This includes not only moisture but strong winds just above the surface — a few thousand feet up. The strength of these winds varies on each forecast model, but generally the consensus is that they will be fairly strong. Some of the stronger forecast models have winds at 900mb in excess of 55 knots.

The main concern is that heavy rain or thunderstorms could cause these winds to mix down, especially right near the front. Regardless of whether they do or not, strong southeasterly winds are anticipated ahead of the frontal boundary, likely gusting over 35 miles per hour at times on Sunday. The threat does exist for some coastal flooding, especially in the typically impacted areas along the NJ  and Long Island shorelines.

Update Schedule: Stay tuned over the next few days for updates, and the latest information including a premium video which is currently scheduled for release on Wednesday evening.