This page is updated daily between 18 and 19 UTC while tsc is updated hourly.Whats new: added a plot of the lid strength index.
NCSU IGW analysis system
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If the LAP (height) ~= Delta NBE then the assumption for balance is violated. This also applies to the Jacobian of the wind field.
At this early stage, it appears that the Lap (height) is
with the Delta NBE, but this is not a sufficient condition for
gravity waves...I will include a plot of the Jacobian of the wind field
since this is supposed to be the 2nd largest
term...maybe that will be a good discriminator.
Flow imbalance is calculated as the residual of the non-linear
equation as shown by Zhang
et al. (2002). Duct factor is calculated as in Koch and Siedlarz
Delta NBE = Lap (geo hght) + Beta * U - f *zeta - 2 * J(u,v)
10^-8 10^-10 1*10^-8 10^-8
Duct factor = Theta (800) - Theta (950) + Theta e (800) -Theta e (400)
500 hPa flow imbalance (contoured),500 J(u,v) (green
low level duct (shaded), and surface pressure (blue contour) is shown
996, 1000, and 1004 hPa :
RUC211 duct factor (shaded) and surface pressure (contoured) for 12, 15 18, and 21 UTC of the current day:
Meteorograms and surface data:
Current Surface Potential Temperature gradient (shaded) and surface potential temperature (contoured) every 4 C
Lid Strength Index after Carlson (1980) : Lid
strength in Celsius to the left, pressure difference between inversion
and the most unstable parcel pressure to the right. Blue is current
radiosonde launch while black is 6 hours behind. Plotted also is the
lid breech temperature (take the lid temperature down to the sfc dry
adiabatically). LSI (black contour) and CIN (blue dashed)
CAPE/CIN/ DCAPE analysis from Emmanuel (1994?) MUCAPE (black) and
DCAPE (Blue dashed)
Most probably CAPE and CIN (parcel with least CIN provided CAPE is
greater than 250 j/kg)
A Time to space conversion analysis of real time surface data
(altimeter setting converted to pmsl ); Observation counts are shaded
below 3. This is a measure of how well the barnes scheme handled the
data (where extrapolation was necesary)AND how much data got into the
scheme (It isn't always the schemes fault!) We have also added a 1km
radar mosaic image to each plot. If you are interested in the technique
and details of the real-time system, click here for my preprint
at the 84th AMS annual meeting in Seattle.
|Date YY/MM/DD TT||Forecast Region||Gravity wave?||How detected:|
|02/12/18 00-12UTC||IA, MN||no surface wave detected (no)||initial band , synoptic scale WV|
|02/12/21 12-00UTC||OK, KA (tul)||no surface wave detected (no)||band Tulsa in clear air radar 18 UTC|
|02/12/24 00-12 UTC||TX, LA, AR (deq,arg,dtn)||wave at back of precip shield (dfw)||LZK and dfw radar|
|02/12/25 12-12 UTC||off long island coast ack||possible wave (?)||ack obs|
|02/12/31 18-00 UTC||arkansas (arg) LA (shv,sgt)||small amplitude back of precip (no)||surface pressure spikes|
|03/02/01 23-?? UTC||Hyannis, and ack,pvc,||large amplitude, back edge of dissipating precip shield||rapid p falls|
|03/02/16 16-00 UTC||Wallops, Philly||pressure pulse? Questionable||pressure spike|
|03/02/22 12-00 UTC||MKL, JAN||possible wave, possible bust||pressure spike|
|03/02/23 12-00 UTC||tulsa ok||no wave detected, lack duct||not detected|
|03/03/26 00-12||TX corpus christie||wavelike derecho event||tied to convection|
|03/04/10 18-06||Virginia (FVX LKU OFP HNZ)||solitary wave / convection?||sfc p fall (unclear convective / wave)|
A note on the meteorograms: When possible stations with 20 minute data will be shown. Although these meteorograms provide lots of information they do not contain enough. For example, on December 25, 2002 ACK had the sfc low go by. Just before this occurred the metar contained a remark, PRR (pressure rising rapidly) while in the midst of large hourly pressure falls. The next ob had the pressure decreased by 3 mb. This might be indicative of a gravity wave but it will be unknown until a large time series of 5 minute obs can be processed.
Generated by firstname.lastname@example.org using GEMPAK and the 80 km ETA/RUC model grids.