Weather Discussion: An vacating upper-level short-wave trough will leave us under NW flow aloft. Timing will be critical for cloud formation/dissipation tomorrow morning, with cloud cover forecasted to be on the decrease by sunrise over the Nebraska region. Previous CLEX field campaigns have observed mid-level cloud formation in similar NW flow regimes... Weather Outlook: Conditions for mid-level cloud formation look favorable for Sunday and On. For Sunday, another shortwave looks to nudge into the NE region with a significant plume of 500 mb moisture. The timing of the models now suggests a possible afternoon mission (will have to wait and see about this). Longer term looks favorable with continued NW flow regime aloft and embedded shortwave disturbances present. Adam/Larry/Curtis
The 12 Oct 2001 CLEX-9 mission over the Scott's Bluff/Sydney, NE region has been completed. Larry was able to sample a long-lived mid-level cloud field for three hours (with a total mission length of four hours). They recorded three complete Lagrangian spirals in a cloud field that ranged from 11 Kft (base) to 21 Kft (top). The cloud field was mostly single layer with a few occurrences of two layers noted. Cloud top temps were as cold as -27 C. Significant cloud top liquid water was also noted throughout the mission. The Wyoming Cloud Radar observed widely varying cloud structure present with higher reflecting ice regions often located about a thousand feet below cloud top. They then ascended to this level for corresponding in-situ measurements of this in-cloud region. Larry reported that they were fortunate again to have unrestricted airspace throughout the entire mission. All instruments were in working order. This is an excellent Lagrangian case study of a cloud field that did not dissipate through sunrise. It is noted (on satellite imagery) that several large adjoining regions of clouds did visibly dissipate through the sunrise timeframe. Adam (from CLEX-9 central)
Sunrise Central Daylight Time Begin civil twilight 7:24 a.m. Sunrise 7:52 a.m. Sun transit 1:29 p.m. Sunset 7:07 p.m. End civil twilight 7:35 p.m.