We started talking about this already back on the 11th of the month before any other outlet was referring to it and how this time frame had the potential for heavy rain to occur. That map can be found on this blog.
This is still going to be the case with the guidance now coming into virtual agreement with the exception of the GFS. GFS agrees on the overall scenario of what is going to transpire but we did not use the model in the final solution due to it seemingly being too far east with the main axis of QPF.
So lets look at the guidance from 12 Z to begin.
12 Z GFS
12 Z GGEM
12 Z UKMET
12 Z ECM
And with the release of the NEW UPGRADED NAM
Now these images above are all at 48 hours and you can see that there is virtual agreement across the guidance on a fairly intense area of low pressure ending up quite far to the west. This would be the primary low!
Now lets break it down:
First of all by the image above you can see a fairly broad area of low pressure. This is what was Invest 95 and what happened was yesterday there was indeed a lower level circulation present but that LLC broke off and became detached from the showers and storms that were further NE. It never became a named system (perhaps with tropical storm force winds still occurring as of this morning it should have) however..the moisture or the tropical moisture plume connection is going to be important.
There is a stationary front to the south that turns into a cold front the further SW you go. You can also see the deep trough that is being carved out in the central part of the USA.The low in the GOM is going to feel the effects of this trough and get picked up by the cold front that you see above.
This will cause the GOM low to move towards the NE. While this is occurring a warm front is going to start to lift off towards the North (associated with the front shown as stationary) and this is going to cause a strong push of WAA into the region (warm air advection) .
Now the question becomes since we have a primary and we also have a secondary whether the secondary remains dominant or the primary does? This is important because if the primary remains dominant the heaviest rain totals will be west near the primary..If the secondary is dominant then the heaviest rain totals will be to the east with more or less a “gap” in between the two heavy rain shields.
While we do not depict it on the map cause it was focused on the NE..areas from east central Ohio west and NW into MI are also in the 2-4 inch range. Guidance does not show the secondary becoming dominant ..however..we feel based on the blend of the NAM/ECM/UKMET/GGEM that this secondary should deepen as it moves up along the coast and with the tropical plume of moisture we should have a heavier area of precipitation on the eastern side..
You can see on the above radar image how this is beginning to take effect. This secondary should also tap into the Atlantic. Now, while the secondary we feel should deepen and become fairly strong ..the energy should merge with the primary energy.
The results will be heavy rain with the potential for some thunderstorms to occur in addition to gusty winds! The strongest winds should be along the coast where winds could gust to 30-40 mph. As far as rainfall is concerned this is our final thinking based on all the above:
One more thing: flood watches could be issued by the NWS for portions of NJ, LI and into SNE along the coast along with wind advisories!
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