CLEX-9 October 19th, 2001 Operations

Synopsis

• The CLEX-9 forecast team has decided to stand by all operations for Friday, October 19th.
  
  
• Weather Forecast (made at 1530 MDT 10/18/01):

  
            Mission Forecast: The models have a patch of mid and upper level moisture 
            embedded in the NW'erly flow arriving near the CLEX-9 target area tomorrow 
            morning.  Weak PVA might trigger cloud formation north of the North Platte, 
            NE region.  The lack of any surface dynamics means that any clouds that do 
            form should be precip free.  Our target region (if clouds do form) would be 
            the panhandle of NE.  Timing on the passage of the moisture indicates that 
            an earlier than usual (i.e. 0500 MDT) morning takeoff might be required.  
  
            Weather Outlook:  Weaker and dryer flow aloft is expected over the weekend 
            as a weak ridge of high pressure builds in over the western US.  Conditions 
            needed for mid-level cloud formation improve early next weak (Mon/Tue) as a 
            large trof starts to dig in over the central US.  Along with this trof should 
            be favorable NW'erly flow over the North Platte, NE region.  
  
            Adam/Don/Larry
  
    
  Morning Update (made at 0300 MDT 10/19/01): 
  
            The CLEX-9 field campaign is on GO status for this morning (Friday 19 Oct 2001).  
            The target region will be North Platte, NE if the mid-level clouds currently out 
            there make it that far south.  Larry should be taking off in the WY King Air by 
            0500 MDT (1100Z).
  
            Current weather:  Significant mid-level cloud coverge is present over east-central 
            WY moving SE into NE.  Cloud tops are around 20 Kft with bases being reported near 
            10 Kft.  IR cloud tops are near -25 C.  The RUC model has a bullseye of 500 mb 
            moisture centered over North Platte at 0600 MDT (1200Z).  This current region of 
            mid-level clouds lines up well with the left-exit region of a jet streak that is 
            begining to move into the region.  
  
            Adam/Don
  
  

Post Mission Update (made at 0930 MDT 10/19/01):

          The 19 Oct 2001 CLEX-9 mission over the Noth Platte, NE region has been completed.  

          Larry called and said they were able to sample mid-level clouds over North Platte, 
          NE for about an hour.  Three straight leg runs were completed (at 20, 16 and 12 Kft) 
          in a mostly ice-phase set of clouds.  Some liquid was observed.  Cloud bases were 
          around 12 Kft.  The King Air was able to arrive over North Platte before sunrise.

          After the straight leg runs were completed, the King Air headed NW into a rapidly 
          dissipating cloud field (diurnal dissipation).  They then climbed to 28 Kft and 
          spotted an AC field over McCook, NE which they then sampled for about 25 minutes.  
          The in-cloud temperature was ~-15 C, and the cloud composition was mostly liquid 
          water.  They ran a series of in-situ and side-looking cloud radar profiles on this 
          AC field.

          After landing in North Platte, NE the CLEX-9 team has decided to stand down a 
          potential 1800Z TERRA overpass mission due to lack of cloud within reasonable 
          flying distance of North Platte.  The aircraft will proceed back home to Laramie.

          John Davis reports that they launched a rawinsonde at 0730 MDT (1330Z) and that all 
          ground instruments were working well.

          Adam (from CLEX-9 central)

Sunrise Information for North Platte, NE

Sunrise   
                     Central Daylight Time          

        Begin civil twilight       7:32 a.m.                 
        Sunrise                    8:00 a.m.                 
        Sun transit                1:28 p.m.                 
        Sunset                     6:56 p.m.                 
        End civil twilight         7:24 p.m.                  

Weather Details

1200Z 500 mb Map



1215Z GOES IR Image and CLEX-9 19 Oct 2001 Target Region


 




1200Z North Platte, NE Sounding


 







 

Aircraft Operations

• UW King Air Operations: TBA

North Platte, NE Ground Operations

• Ground Instrument Status: Everything working well
  

Data Collection Highlights:

• Summary: Updated as soon as possible