Deep Moisture From The Deep Tropics

Just a quick update on the deep moisture feed from deep in the Gulf Of Mexico.  The IR picture clearly shows this moisture streaming up the Appalachians and towards the Mid-Atlantic states.  This moisture plume is poised to dump copious amounts of rainfall over PA during the mid-week period.  Note Katia off to the east of the Bahamas.

Speaking of plumes, here are the plume diagrams from the Short Range Ensemble Forecasts (SREF) showing that most of the runs indicate at least a 4" rain event to affect KMDT.  Let's hope that 11"+ run doesn't verify!  I usually like to use these plumes for winter weather precipitation events, but the quantity of the rainfall can be quickly analyzed with these plots.

As can be done with a normalized plot on a map.  However, when normalizing the model output, the extremes are smoothed and often what is mapped is less than what actually falls from the sky.  That is not a good scenario for the Mid-Atlantic as seen below.  This map is quite disconcerting for the flooding potential that will occur over PA later this week.  And the Susquehanna is not outside the possibility of flooding either as this rainfall would be onto already saturated ground....nearly 100% runoff.  Here is that most concerning map.

As for Katia, the upper air graphic below argues that Katia could just as easily be pulled towards the continent as getting swooshed out to sea by the westerlies.  The ridge to her east and the trough to her west are in such a position that this hurricane could get moved either way.  If the trough is just a bit deeper to the west or the ridge just a bit higher to the east, that storm will hit the US, likely on Long Island and then up into New England.  Either way, very large surf will be present all up and down the east coast this week.

So off to finish watching the Phillies...here's hoping they get 5 innings complete as some fairly heavy rain is on the doorstep at the Bank!

Enjoy your Tuesday.

Smitty

AA:  Heavy rain a near certainty this week with us receiving ~5" in total by Thursday!