A Look at the 18 Z GFS- Behind The Scenes!

Usually i do not do an intermediary update such as this when it comes to the 18 Z model runs. However…there is alot of untruth going around again that I feel the need to talk and look specifically at this model run.

This is hour 120 of the 18 Z GFS and what i want you to notice is that there is precipitation in the southern stream and yet on the 500 mb chart we see no notice of any energy depicted. So it begs to question what the precipitation along the south if there is no energy being depicted? However more importantly when you follow this run out it looks very close to the 12 Z ECM…Remember the red flags to the ECM being the UKMET and the NOGAPS and then one needs to call into question what the 18 Z GFS just did. But now lets look at hr 120 again…

The diagram above actually shows where the low pressure in the lakes should be with a slower solution and also points out that there i no southern stream energy depicted in the 18 Z operational. However..lets look at the ensemble means of the very same run…

Now as you can see the means has a depiction of a southern stream energy which makes sense if you are going to have moisture along the southern Gulf Coast such as the operational shows.

Lets look at 120 hrs now..

Now you are noticing the southern stream energy over N C florida. Notice on the operational we are completely lacking this feature.

At 132 hours you have the secondary right off the delmarva and the two energies begin to merge together.

As you can see the 18 Z means is much more like the 12 Z operational GFS and with some more adjustments could become a solid snowfall along the east coast from PA/MD line north.

Look for that southern stream energy to become more evident on future GFS runs and a slower northern stream system and a further sharpening of the trough.  This is what to look for on future model runs and this is not too far off to becoming “interesting” to say the least!

Remember folks its all about the pattern!