Monday, September 02, 2013

Warm and Humid with Scattered Showers and Thunderstorms

Its another very warm and humid start.  Temperatures as of 7am are in the middle 70's.  There are some thunderstorms in the area, mainly across Eastern PA just north of the Allentown area.  These are slowly moving east, yielding brief heavy rainfall.  There is also considerable cloudiness around with areas of fog in many locations, thanks to a weak southerly flow aloft.

Yet another somewhat tricky forecast today regarding clouds and precipitation.  There have been several impulses or triggers for convection out ahead of a cold front and upper-level low moving into New England.  This will keep many locations under the threat for showers and thunderstorms throughout the day.  With the weak flow, the main threat is heavy rainfall.  Like yesterday, believe that the majority of cloud cover and precipitation will be mainly from the city and points north in PA and NJ.  Areas south of the city into Delaware may see much more sunshine.

Whatever fog and extensive cloud cover will take some time to burn off during the morning hours.  Temperature guidance for today is all over the place, ranging from the low 80's to almost 90 degrees if you see a lot of sunshine.  With temperatures already in the middle 70's, it won't take much sunshine to warm.  More confident we'll see highs only reach the lower 80's in northern sections, north of the city.  But from the city and points south, its all about how much sunshine we'll see and believe highs will be warmer into the middle and upper 80's.  It's very possible some areas in Delaware reach 90 degrees.

A cold front from the west will push through the region overnight and tomorrow morning bringing drier and much less humid conditions.