Strong NW Atlantic storm

After providing some training on the RGB Airmass products this morning, I joined the Ocean Prediction Center’s (OPC) forecast discussion. First thing I noticed was that the forecaster giving the discussion (Atlantic Desk) had the SEVIRI RGB Airmass product up and what I saw astonished me. Typically I am well-informed on what is going on in the world, but I was very impressed with the rapidly deepening low south of New Foundland. This is another case of a hurricane-force storm affecting the OPC warning area, but this time, farther west.

I have included a couple images of this impressive storm. At last check, the central pressure was down to 979 mb and an aircraft sampling the storm’s bent-back front structure has reported winds in excess of 70 knots (81 mph). An early morning ASCAT pass found winds just under 65 knots on the western quadrant, while an OSCAT pass found a 65 knot wind flag near the tip of the comma head. The RGB Airmass product shows the stratospheric air within the advection jet intersecting the comma head where the highest winds are being observed.

The SEVIRI RGB Airmass product with an OSCAT wind pass overlaid (valid at 1745z, 02/03/12) highlighting the high winds coincident with the advection jet and PV anomaly.

The following two images show a small, concentrated vort-lobe rotating around the southeastern quadrant of the storm. To my knowledge, this didn’t get sampled by the aircraft, but it shows some of the microscale phenomena that occur in these events. Note the very dry stratospheric air coincident with the small feature. I included a close-up visible image showing just how small this vort-lobe is.

The SEVIRI RGB Airmass product (valid at 1845z on 02/03/12) showing the strong stratospheric intrusion with the small vort-lobe (yellow circle) rotating around the larger-scale low.

GOES-East Visible imagery (valid at 1845z on 02/03/12) showing a close-up of the vort-lobe (yellow circle) in the North Atlantic storm.

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