Sunday, March 25, 2012

Forecast for Monday, March 26, 2012

3 Words... Wind, Fire, and Freeze.

You know this has been a bit of an odd Spring when Mount Pocono is warmer than Philadelphia by several degrees at late-afternoon. The northeast wind has been keeping the eastern half of our region under a damp, cloudy, and cool regime all day and has resulted in what will be a "bust" for temperatures in Philadelphia. It is unlikely that mid-sixties can be achieved by the time the sunshine sets with significant clouds still in place and winds still blowing from the NE.

We do expect the winds to become variable/north tonight and drier air to start moving in from the northwest. This should mean a gradual decrease in clouds.

For Monday, a strong cold front will move through the region. However, moisture will be limited and I just anticipate intervals of clouds and perhaps a sprinkle in a few spots. Winds on Monday as gusts may exceed 40 MPH in many locations. I wouldn't be surprised to see a wind advisory raised for portions of the area. With dry fuels and light rain over the weekend, that will likely not be enough to eliminate fire concerns. The strong winds will dry what surface moisture there is out and relative humidity values crash to around 30-35%. Therefore, enhanced fire danger is likely on Monday Afternoon into early Monday Evening. A red flag warning also wouldn't surprise me.

A damaging and potentially devastating freeze is looking more and more likely on Monday Night into Tuesday Morning. With the growing season up to four weeks ahead of schedule, many fruit trees and other sensitive plants have already had buds and flowers emerge as far north as the Lehigh Valley and North-Central New Jersey. We expect temperatures dropping in the upper twenties and lower thirties. This will destroy them, especially if these temperatures occur for three or more hours and perhaps mean limited production this year. Some guidance is suggesting 26 or 27 degrees. If that is the case...some areas would be looking at not only a freeze...but a hard freeze. In a hard freeze...there is even less of a chance of survival. The National Weather Service has already raised a freeze watch for this time frame. I can only hope for the best.

On Wednesday, a warm front will move in with a round of showers and isolated thunderstorms. If temperatures surge into the sixties south of the warm front...the warm sector may see a round of strong thunderstorms in advance of the cold front Wednesday Evening. We are hopeful that Philadelphia actually doesn't bust on Wednesday, but stay tuned for later forecasts as we get closer to the event.

High pressure dominates for the rest of the week.