3/15/2011 Extended Forecast

Clouds will be increasing this evening ahead of an area of low pressure that will be riding along a cold front boundary. Rain will likely develop, with possible thunderstorms. Areas of Southern New Jersey have the potential to enter the warm sector of the low pressure area. If this is the case, there could be quite a bit of deep layer shear, or wind moving in different directions in different parts of the atmosphere. There could potentially be some low-level hodographs as well which can be indicative of tornado activity. The high resolution models have been indicating a convective look to this storm system since the weekend. My problem is finding sufficient instability this early in the morning, especially during the month of March. Based on the high-resolution modeling indicating the potential for thunderstorms, I am comfortable with leaving thunderstorms in the forecast. The thunderstorm threat will dependent on the low pressure track and it is a bit difficult to determine whether it will pass just west…over us…or just east of the Garden State. This clearly makes a difference. The low confidence part of the forecast is the potential for damaging winds or a tornado. This will be highly dependent on instability and how far the area gets into the warm sector prior to the cold front. The chances are minimal, but not impossible after analyzing the data.

Rainfall should average 0.50” to 0.75” across our area. This amount, if in actuality, will not be enough for flooding in most areas. The one EXCEPTION will be the Passaic River Basin. With these waterways at or above capacity, even 0.25” of rain will renew the flooding here to at least some levels. Thunderstorms have the potential to produce localized amounts in excess of an inch and although not widespread, this is another reason thunderstorms are of a concern Wednesday Morning. A flood watch was posted Morris County into Northeastern New Jersey due to the Passaic River basin. A BIG NOTE here is that the 12z GFS did indicate 1.00” to 1.25” right over Western New Jersey and if this solution were to be actuality, then we would be talking about stream and creek problems in a bit of a more expansive area.

Thursday will be much warmer, behind the cold frontal passage on Wednesday. Highs should reach well into the sixties. On Friday, a strong southerly flow will push temperatures into the lower seventies over a widespread area with some middle seventies. A cold front will arrive Friday Night. Some showers and thunderstorms will be possible and with the warmth, instability should be present. Between now and then, a good moisture source for the front will have to be located to result in sufficient convection formation.