Category Archives: Weather Updates

Weather Updates

FASTER MOVING ISAIAS- UPDATE

Tue 08:41 AM Update — graphics added below

The 2 AM (06UTC) runs of the models show the following changes in the forecast for tropical storm Isaias—

  • The storm is moving faster than previously forecast-  peak winds and rain rate will reach us between 10 AM and 1 PM.
  • The track of the storm is a bit further westward.
  • Rain totals will be the highest to the west of Philadelphia, in Lancaster county.  Still an additional 2-4 inches to fall. The precipitation maps posted yesterday still hold.
  • Higher localized rain amounts in thunderstorms.
  • Wind gusts will peak about 11 AM and again at 1 PM.  Wind gusts around 60 mph possible in the Philadelphia area, higher in NJ.
  • Rain will be ending by 2-3 PM

Some differences exist with areas of max rainfall.

Below is the latest GFS model accumulated rain forecast (from 2 AM, which does not include the rain from last night prior to 2AM. )

GFS forecast accumulated Rain from 2 AM  onward (Click on image for a larger view.)

 

Here’s the very latest HRRR (High Resolution Rapid Refresh) hourly model from 7 AM —

HRRR accumulated Rainfall from 7 AM

 

 

 

Weather Updates

FRIDAY FAY UPDATE

Updated Fri 05:14 PM — Philadelphia Airport has had over 4 inches of rain so far!  The NBM forecast from this morning was pretty good.   The NAM NEST had the rain tapering around 2 PM; obviously a wrong call.
Updated Fri 09:49 AM —Updated with latest Model Blend (NBM) from 8 AM this morning.

Updated NBM (8 AM run) accumulated rain forecast.  (Click on image for a larger view.)

Updated with latest model blend (NBM) accumulated rain graphic.

The models that are run at 2 AM EDT (06z) continue with a similar forecast as last night. Rain will be starting shortly, if it hasn’t already started in your area.   Precipitation amounts look to be a generalized 1.25-2 “ of rain with some local areas having 3-4”.   (I’ll post a graphic shortly.)

Latest Model Blend (NBM) Accumulated Rain Friday.  (Click on image for a larger view.)

The only change noted in the latest models is a tapering in the rain about 2 PM around here, vs the previous forecasts which had the moderate rain going into the early evening hours.   It appears that the main slug of precipitation shifts northward into northern NJ and northeastern PA.

Here’s the most recent (06z) NAM NEST (High resolution) accumulated rain forecast with a somewhat different area of precip maximum:

NAM NEST Accumulated Rain forecast  (Click on image for a larger view.)