About Sandy: Research Questions
1. Pre-genesis:
Address to what extent, if any, antecedent TCs (e.g., Rafeal and Tony) in the North Atlantic may have helped to create a more favorable environment for the genesis of TC Sandy. TC Sandy was a very large storm from the get go. At issue is why. An overarching question, to paraphrase from the many dead Marlboro Men, is: It's not how big you make it, but how you make it big. Close only counts in horseshoes and hand grenades, but size matters when it comes to TCs. Role of a Caribbean gyre in the Sandy genesis?
2. Genesis, intensification and northward motion:
Did a low-latitude anticyclonic wave breaking event and a weak Sandy-trough interaction over the eastern Gulf of Mexico and Florida conspire to keep TC Sandy moving northward after the storm weakened from its transit across Cuba and did this Sandy-trough interaction contribute to forecast uncertainty 4-6 days in advance of the New Jersey landfall?
3. Flow uncertainty over the western and central North Atlantic:
Considerable flow uncertainty associated with a remarkable cyclonic roll up was evident over the western and central North Atlantic from 4-6 days before Sandy's New Jersey landfall based upon d(prog)/dt loops. Despite this flow uncertainty, the circulation around Sandy proved to be relatively insensitive to the details of the varying circulations to the north and east over the open Atlantic. Was Sandy too big to fail (so to speak) and, if so, why? Many more GFS ensemble members than ECMWF ensemble members appeared to impacted by the flow uncertainty over the Atlantic as manifest by earlier GFS forecasts that Sandy would make a "right turn" into the open Atlantic before it reached the latitude of the Carolinas. At issue is why. Rare easterly middle and upper-level flow over the North Atlantic associated with anticyclogenesis and high-latitude blocking (AO << 0) conspired to preclude strong westerly steering currents.
4. Hybrid Sandy and observed strengthening 12-36 h before landfall:
Sandy appeared to have elements of a TC, a hybrid storm, and an extratropical cyclone with a warm-core seclusion in the 12-36 h period before landfall in New Jersey. How do we sort out the details and how should we define ET under these circumstances? Did the strong upper-level trough to the west of Sandy influence Sandy or was it influenced by Sandy? Was Sandy a warm seclusion or a hybrid cyclone…..or was it both? For sure, it was a TC with snow in conjunction with a second, and stronger, TC-trough interaction.
5. Frontal band to the west of Sandy:
The heaviest rains associated with Sandy fell along a strong baroclinic zone to the west of Sandy from eastern Virginia north-northwestward across the DC metro area to western Pennsylvania and New York. The strong baroclinic zone formed when cooler air from the southwest associated with a second Sandy-trough interaction became juxtaposed with mild Atlantic air wrapping around Sandy to the north and east. Frontogenetical forcing along this baroclinic zone was extreme and the thermally direct ascent helped to sustain the observed rain band. Need to investigate whether Sandy's large size and weak deep-layer shear observed by aircraft reconnaissance helped too inoculate the storm from the direct influence of the strong baroclinic zone to the west with impact on the subsequent ET. Divergent outflow directed westward associated with the irrotational wind in the upper troposphere exceeded 25 m/s, implying a large region westward negative PV advection. What role does this negative advection of PV by the irrotational wind in the formation of a rather unconventional-looking PV hook over "Sandy Hook?"
6. Sandy landfall:
Radar loops suggest that a mid-level vortex made landfall in New Jersey between 1800-2000 UTC 29 Oct while the low-level circulation associated with the reported 945.5 hPa pressure near Atlantic City made landfall near 0000 UTC 30 Oct. As issue is to what extent the radar-indicated midlevel vortex was related to the aforementioned strong frontogenetical forcing and/or was a manifestation of the development of a tilted TC vortex in the vicinity of landfall.
