March 6-8th Flooding Rains & Snow

Looking at the 12 Z guidance and also part of the 00z guidance from tonight (NAM) …we have no reason to really change any thinking from what we put out yesterday. The threat of very heavy rains is still very much on the table. The possibility of some areas ending as snow is still very much on the table and as we will see the ECM has some decent snows N & W of KPHL..

Lets look at the guidance ..

00z NAM as you can see only goes out to 84 hrs but it shows the threat for heavy rain with the area of low pressure still to the south at that point and time.

GFS

GGEM

UKMET

ECM..as you can see the above models are all generally in agreement for the threat of very heavy rains across the region.

Now, where this gets a little interesting is with the European Computer guidance. Off to the N and NW of the low pressure is an area of high pressure on all the models of 1035 +. Whenever you have a high pressure of that strength in SE Canada you have to be careful of colder air seeping southward into the region.

To complicate matters is we have an approaching cold front which is going to be the trigger for the heavy rains and perhaps some strong gusty winds as well. Behind this front will be colder air which will be moving towards the east. Does this colder air arrive while the rainfall is still falling is the question that still needs to be answered.

This is where the ECM gets interesting it has a total of 2-3 inches liquid across the region but it also has the cold front crossing and then the 850s crash..surface goes below freezing and precipitation changes to snow and up to 6 inches N & W of KPHL into the ABE area.

Now it is too early to know whether for certain this is going to occur or not but this is something we mentioned as potentially happening with the colder air come into the region.

Stay tuned for more information!