A couple of days ago all the models were diverging on this "Sunday Storm". Some had it tracking way off the coast on Saturday, others had it not even forming well, and some had it moving slower and closer to the coast. The dynamics of this system were not figured out at all.
INITIAL DISAGREEMENT
Just yesterday the models were in complete disagreement over the event. The GEM model plotted out two storms, one on Saturday and the other on Wednesday both affecting our region. While the GFS had one larger storm affecting the region on Monday.
WHAT ARE THE MODELS HAVING TROUBLE WITH?
Most obviously, it is 5-7 days in the future.
Secondly, the models do not know how the upper air system would play out
TODAY, THE MODELS NAIL DOWN THE GENERAL FORM OF THIS STORM
Whether you look at the NAM, GFS, or GEM they all believe there will be a storm forming over the center of the country as a result of a cut-off upper-level low. This happens when a piece of upper-level energy becomes disconnected from the larger source. This allows the storm to move slower and not be pulled along to the east by the jet stream. The GFS picked up on this early while the GEM was initially far off and now The NAM also is in agreement.
Below are upper air maps which ran on two different days 1/10 and 1/11. They plot out upper air masses which dictate the weather and is a good indicator of where storms form and where they will go.
2 GEM RUNS FROM 1/10 VS 1/11 (Most recent)
You can see how the most recent model run for this time has an upper-level cut-off low that is disconnected from the larger air mass.
2 GFS RUNS FROM 1/10 VS 1/11 (Most recent)
You can see here that the GFS model in both runs plotted out a cut-off upper-level low. The latest run having the cut-off low more disconnected from the larger air mass, meaning that a disconnected system from the jet stream will form.
NAM RUN FROM 1/11
The NAM is a medium range model, and this system is just in its time range. NAM also plots out a cut-off low.
You can see all the models are banking on this storm forming off a cut off upper-level low and moving south into the center of the country. Over the course of yesterday, the GFS was trending towards this scenario. The GEM on the other hand, had no cut-off low at all but now does. The NAM is now also plotting out the same situation. Consensus.
SOOO BIG STORM FOR MARYLAND?
Now it's too far to make any determinations on the exact track of the storm with regards to Maryland but there is reason to believe that the storm will merge back into the jet stream and strengthen up the coast. Eventually as the jet stream dips again, it can pull the storm northward, phase together and form an intense storm. This requires a lot of timing and sequencing of systems but some sort of phasing (merging back into jet stream, pulling storm north) situation is looking likely.
POTENTIAL STORM TRACK
GFS 12Z 1/11 RUN STORM IN MARYLAND BY SUNDAY NIGHT
Comentários