Category Archives: Tropical Storm Outlooks

Philadelphia Area Weather Forecasts, Tropical Storm Outlooks

STORM ISAIAS UPDATE FOR THE PHILADELPHIA AREA

Mon 10:45 PM Update — More new model data. Wind gusts may exceed 60mph in Philadelphia and immediate suburbs.
Mon 10:15 PM Update — Tonight’s short range models just becoming available continue with the forecast of a generalized 3-5 inches of rain.  Heaviest amounts in the western suburbs. The precipitation maps posted below are still valid. The storm will be approaching sooner and moving faster. The precipitation rate peaks around 11 AM -2 PM with over an inch of rain per hour falling. Wind gusts are higher, especially in NJ.  

Tropical Storm/Hurricane Isaias continues to move up the coastline.  Very heavy rain continues to be the main threat from this storm. The heaviest rain may fall over a period of just a few hours.

The trend has been for the heaviest rain to fall slightly further west than yesterday’s model runs.  Some models are predicting amounts as high as 5-7 inches of rain in some spots!  The heaviest rain will fall between 11AM and 3 PM Tuesday.

The peak winds will occur around 1-2 PM.  Gusts around 35-50 MPH are forecast by the latest GFS in the PHL area.

GFS wind gusts forecast 1 PM EDT Tuesday  (Click on image for a larger view.)

 

Here are the latest models with their rainfall totals –

GFS model accumulated rain forecast  (Click on image for a larger view.)

The latest National Blend of Models (NBM version 4.0 ), often correct for QPF values, has even greater amounts—

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

The latest NAM NEST model has the heaviest rain more westward—

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

The Canadian Global (GDPS)  is also a bit westward with higher amounts—

Canadian (CMC- GDPS)  Rain Forecast (Different color coding)  (Click on image for a larger view.)

The German ICON model has a similar precip forecast—

German ICON model  (Click on image for a larger view.)

So a generalized very heavy rain event is expected

Tropical Storm Outlooks

HURRICANE DORIAN UPDATE

Hurricane Dorian continues to follow the track predicted by the greatest consensus of models.

Here’s the current COAMPS-TC forecast track, which like many other models, has the storm brushing the South Carolina and North Carolina shores—

COAMPS-TC  forecast from Wednesday morning

 

Hurricane Dorian will affect our area at a distance of Friday.  Here is the latest SREF (Short -Range Ensemble Forecast) for Friday afternoon.

A chance of light showers at the Jersey Shore, windy conditions for Friday.  (The GFS and NAM keep the shore dry.)  Winds 20-25 mph with some higher gusts.

Cloudy conditions expected even into the Philadelphia area.