Philadelphia Area Weather Forecasts

FORECAST CHANGE

The model runs from last night (06z – 2 AM EDT) show a change in the forecast for today, Saturday.

  • More sun and less high cloudiness until about 4 PM, when clouds move in.
  • High temps 88.4º sd 1.9º.  My guess is that it might hit 90º.
  • Increasing chance of scattered thunderstorms as early as 5 PM in PHL.

Sunday has an highly elevated chance of scattered thunderstorms throughout the day.

The storm with the difficult name to pronounce will hopefully be an easier forecast to track — Hurricane  Isaias.

The track of Hurricane Isaias appears to be somewhat more westward, affecting more of our area on Tuesday—

GFS (pre-release version 16.) 12 hour rain forecast 2 PM Tuesday  (Click on image for a larger view.)

 

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

The weak cold front that moved through on Friday will move north as a warm front later Saturday into Sunday.  Showers expected with the warm front Saturday night.  My regular readers know that a tropical system or hurricane near the continental US often plays havoc with the model forecast specifics.

Saturday—

  • Significant and increasing high level cloudiness (cirrus).  Lower level clouds increase during the late afternoon and early evening.
  • High temp 87.0º sd 2.0º
  • Dew points mid 60s.
  • Winds calm to very light from the SE at 0-6 mph

 

The warm front moves north, but unstable and humid air may result in thunderstorms Sunday afternoon, especially west of Philadelphia.

Sunday—

  • Cloudy in the morning, sun breaks out during the late morning or early afternoon.
  • Showers linger early in the morning.
  • Thunderstorms and showers possible later Sunday afternoon.
  • High temp 91.3º sd 2.6º  (larger than average spread)
  • Very humid!  Dew points near 75º
  • Winds increasing 10-15 mph from the S and SW.  Becoming gusty in the afternoon.

GFS (pre-release version 16) forecast Hurricane Isaias on Tuesday morning at 8 AM, currently the closest forecast approach to our area —

GFS v16 forecast for Tuesday 8 AM  (Click on image for a larger view.)

The model blend (NBM) shows much more rain to the west on Tuesday—

NBM 1 hour rain forecast for Tuesday at 8 AM  (Click on image for a larger view.)
Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

2 Comments
Sat 10:36 PM Update — The relative humidity as expressed as the dew point looks slightly more tolerable on Sunday afternoon than previously forecast.  Still a high  of 93  (Blue Bell)—

Model Blend temperature and dew point forecast for Sunday

A weak frontal boundary will move to our south this evening, ending the showery weather. Somewhat drier air will move in for Saturday with a mix of clouds and sun. It will still be humid.

The boundary will be just to our south and their are signs that it will move back as a weak warm front later Saturday afternoon. An increase in clouds and spotty showers are possible Saturday afternoon from 3 PM  to 7 PM. (Tonight’s models just becoming available downplay the chance of showers.)

It will be very warm and humid on Saturday, but the real heat and humidity returns again on Sunday.

Saturday —

  • A mix of sun and clouds.  An increase in clouds with spotty showers possible after 3 PM.
  • high temp 89.0° sd 1.9°.  Dew points just below 70°
  • winds calm, very light E—> SE—> SSW

Sunday—

  • Mostly sunny.
  • high temp 93° sd 2.0°.  Dew points 69°
  • winds W 6-8 mph

Weather… and Other Things 'Up in the Air'