Thursday, August 15, 2013

The Gulf System, Stalled Front, and Impact On Us

The tropics are starting to stir with two systems of note. One, in the far eastern Atlantic, will track west over the coming days but it's a few thousand miles away from us and closer to Africa than it is to anything over here. We've got plenty of time to watch it spin across the Atlantic.

Closer to home, an area of thunderstorms that was near Venezuela a couple of days ago has tracked to the Yucatan. Modeling has moisture from this cluster of thunderstorms and weak low pressure pulling northward towards the Southeast coast of the US over the next couple of days.

There's a fair bit of discrepancy on specific evolution of any system in the Gulf of Mexico but the track generally suggests a northerly component -- heading towards Alabama or Florida anywhere between Saturday and Monday depending on which computer guidance you prefer. I'm using the GFS as a guide more for track, less for timing but the timing part may ultimately be right.  In any event, whatever nudges north into the Gulf probably does not amount to much from a wind standpoint but this system may get just windy enough to generate a tropical storm designation if it can develop a closed low. This system will be more of a rain producer for the Southeast than anything else as it pushes north as it will be interacting with a trough in the atmosphere and the upper level atmosphere is not conducive for rapid development beyond a minimal wind speed (40-50 mph) tropical storm, if it even gets that far.

Meanwhile, the frontal boundary that pushed through our region on Tuesday has stalled out near the Outer Banks and the Carolina coastline. This frontal zone will begin to slowly ooze back northward towards us, spreading clouds northeast into our region on Friday night and for the weekend. Saturday and Sunday won't be as nice and sunny as today is, unfortunately, but we should be able to coax a little bit of sun out of Saturday in spots as the frontal zone and any assorted disturbances will still be away from us a bit.

However, Sunday provides the risk for mainly cloudy skies...and for southern regions, periods of rain as the frontal zone pushes north.  IF something organizes in the Gulf and scoots north quick enough, we could see some of that remnant moisture push into Delaware and South Jersey to enhance the rainfall, perhaps even with rain into the city although those odds for rain are lower as one pushes north.  Modeling, as I mentioned earlier, varies on how much moisture gets north and how quickly it does so. However, with the frontal boundary trying to push its way back north the risk of showers will  increase for at least southern parts of the region on Sunday.  Some of the rain to our south on Sunday could be steady to heavy depending on how much tropical contribution takes place but in any event the second half of the weekend, for Delaware and the Shore, may not be as nice as the first.