Back To Home
The Story Behind the Weather - By Forecaster John Ensworth M.S. - 

The Discussion of Weather Events Daily for Philadelphia and Pennsylvania

 Last updated: 09/15/2003 10:38 AM
 

Good Afternoon Philadelphia!   

The BIG story is hurricane Isabel, I know... but first let's talk about the immediate story. The rain over the last 24 hours has been from Philadelpha proper north and eastward.  Has this been the year of rain or what?

The National Weather Service Doppler Radar rainfall total estimates shows an amazing 6 + inches out west with a broad swath of 2" rainfalls to our west and northwest.  This is not good news if we get Isabel here at the end of the week.  The soils are either very wet or at least moist everywhere from the last many months of rain. 

Thunderstorms are rolling over the city this morning with a ripple of low pressure ahead of the cool from approaching (now in western PA).

The visible satellite view shows a swirl in the clouds off the coast with what 'might' (amazingly) be a circulation left over from the remains of Henri (the storm that would not die). You can see the clearing behind the front in western Ohio. 

The cold front is going to slow down now as it bumps up against the stubborn high pressure system to our east. This will allow rain and thunderstorms to form pretty much state wide for the next few days.  Again, we don't need a wet ground before a major hurricane effects the area!

So let's look at Isabel this morning.  It is a very strong hurricane with sustained winds of 140mph (not too far, really from a Cat 5, don't feel safe just because it is called a Cat 4 hurricane--- that is still an extremely devastating storm strength!!!).   It is showing some signs of turning to the north. Yikes.

Over the next 3 days, it is expected to weaken to a Cat 3 (good news!  relatively speaking) hurricane and head for the N. Carolina.  

Five days out it passes over the interior of PA.   BUT other forecasters are predicting more recurving and are targeting Atlantic City, NJ. All these projected paths seem to be aiming for our fair city. 

The storm itself has hurricane force winds about 100miles out from the center.  This means a lot of people will see damage when it comes to shore.  

Here are the areas of the coast most expected to get hit this morning.  Remember, if it does go to our west, we'll be on the side with the most violent winds, heaviest rains, and tornadoes.  We can hardly win in this situation.  Batton down the hatches!

Here are the winds this morning at about 18,000 feet above sea level (the 500mb map). The big trough (marked in red) will be the thing that steers the system up the flow (as shown with the blue arrow). 

So here is what the GFS model is saying...Monday 2pm and rain is spreading all over ahead of the approaching front. 

Tonight 8pm, and the rain continues in many places. 

Come Tuesday morning 8am and the front is pulling up to the north out of the way of the approaching hurricane (please stay!). 

Then we jump to Thursday night 8pm when the GFS shows the impact moment. 

Then we are under tremendous unbelievable rains, strong winds and possible tornadoes Friday morning. 

And it begins to pull north into Canada by Friday night 8pm ish.

Watch the news closely for the preparations you need to make and check back here for another update tomorrow.

Meteorologist  John Ensworth

Surface Station sky cover color key: