A nor’easter was poised to bring significant winter weather impacts up the east coast January 3-5. Early on the 3rd, snow was already falling across the southeast US as the system began to strengthen just off the coast. GOES-16, which recently took over as GOES-East, provided stunning/useful views of the system as it progressed.

The Day Cloud Phase Distinction RGB, previously discussed here, allows for easy distinction between low/mid/high clouds and snow. In the scene highlighted (Fig 1), the high clouds and convection (cold ice clouds) appear as reds to almost yellow, the low clouds (warm water clouds) are aqua/blue, and the snow is green. The clear sky, snowless land surface is a dark blue.

Figure 1: 3 January 2018 GOES-16 5-min Day Cloud Phase Distinction RGB over far southeast US. Full res

The RGB makes these distinctions more obvious than when viewing any single channel, such as 0.64 um VIS alone (Fig 2).

Figure 2: 3 January 2018 GOES-16 0.64 um VIS over southeast US. Full res

The nor-easter rapidly intensified during the evening of the 3rd as it accelerated north just off the east coast. The characteristic baroclinic leaf structure of the intensifying system is obvious in IRW imagery (Fig 3).

Figure 3: 3 January 2018 GOES-16 5-min, 2 km IR Window channel imagery. Full res

The mid-latitude cyclone had deepened considerably and grown massive by the morning of the 4th, as depicted in the GOES-16 IR to VIS transition (Fig 4).

Figure 4: 4 January 2018 GOES-16 5-min IR to VIS transition. Full res:

Derived Motion Winds (DMWs) from GOES-16 were plentiful in the vicinity of the storm system (Fig 5). Low level winds measured over 70 knots in the vicinity of the low center over the ocean. Meanwhile, winds within the upper-level jet on the north side of the system measured to 160 knots between 200 and 400 mb!

Figure 5: 4 January 2018 GOES-16 water vapor imagery and Derived Motion Winds. Full res

By the evening of the 4th, the system had traveled up the east coast and was just off the coast of Maine, producing strong winds and heavy snow along its path. GOES-16 full disk visible imagery from the day shows the vastness of the storm during the day (Fig 6).

Figure 6: 4 January 2018 GOES-16 full disk VIS. Full res

Finally, a 24-hr, 30-min GOES-16 6.17 um “upper-level water vapor” view of the rapid strengthening stage of the cyclone from the evening of the 3rd through the evening of the 4th (Fig 6).

Figure 6: 4 January 2017 24-hr GOES-16 30-min 6.17 um “upper level water vapor imagery”. Full res

Bill Line, NWS