boulder tamdar meeting - ed szoke 1 august 25, 2005 ruc – raob – tamdar soundings ed szoke* noaa...

Boulder TAMDAR Meeting - Ed Szoke 1August 25, 2005

RUC – RAOB – TAMDAR SOUNDINGS

Ed Szoke* NOAA Forecast Systems Laboratory

*Joint collaboration with the Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO


TAMDAR soundings vs RAOBs – some observations

● At the time of the last meeting...● Found lots of variability in the TAMDAR soundings

● Often soundings close in time were not consistent ●Now...

● Much less variability ● Soundings tend to show good consistency ● And generally compare better to nearby raobs


Overview● Assessing TAMDAR data quality...quick review

● Compare TAMDAR soundings with each other● Compare to a “verifying” raob sounding

● Concentrated on DTW and MSP and PIA

● Examining impact of TAMDAR on RUC forecasts● Look at RUC forecast soundings with and without

TAMDAR and compare to raobs● Also compare RUC analyses

● Potential forecast value of TAMDAR soundings● Consistency and potential usefulness of TAMDAR

soundings...a brief case


TAMDAR soundings vs RAOBs – Weather at 1200 UTC 19 August 05


TAMDAR soundings vs 1200 UTC 19 August 05 DTW RAOB – flights to ENE



Agreement is not as good but note TAMDARS are heading NW and the raob would have headed to the ene.


TAMDAR soundings vs RAOBs – DTW 1200 UTC 22 August 05

Quite a bit of lower level moisture overthe Upper Midwest.


TAMDAR soundings vs DTW RAOB – flights to the SE


TAMDAR soundings vs DTW RAOB – flights to the ENE


TAMDAR soundings vs DTW RAOB – flights to the NW

Note that the raob heads to the ESE


TAMDAR soundings vs MSP RAOB – flights to the E

Note the good consistency between TAMDARs 2 min apart.


TAMDAR soundings vs MSP RAOB – flights to the E-ENE

Not sure about the 1231 UTC TAMDAR flight...


TAMDAR soundings vs MSP RAOB – flights to the S

Excellent agreement on the height of the inversion base.


Next we will look at impact of TAMDAR on the RUC

- Examine RUC with (“dev2”) and without (“dev”) TAMDAR - Using mainly DTW and MSP locations

- Look first at RUC analyses and compare to raobs

- Then see if impact is seen in the forecasts by looking at mainly 3 and 6 h forecasts and comparing to raobs.


RUC analysis soundings vs RAOBs – 18 August 2005

Surface map with radar for 1200 UTC.


RUC analysis soundings vs DTW RAOB – 18 August 2005

Comparison of RUC analyses for 1200 UTC with (dev2) and without (dev) TAMDAR. Appears to be a better match to the sounding when the TAMDAR data was included.


RUC analysis soundings vs MSP RAOB – 1200 UTC 18 August 05

The same type of example from MSP; could argue that dev2 is a slightly better match to the raob.


RUC forecast soundings vs RAOBs – 0000 UTC 19 Aug

Comparison of RUC forecast soundings for Detroit at 0000 UTC – 3 h forecasts. -soundings are different, but dev1 (w/o TAMDAR) may be closer match to raob.



Comparison of RUC forecast soundings for Detroit at 0000 UTC – 6 h forecasts.



Comparison of RUC forecast soundings for Detroit at 0000 UTC – 9 h forecasts. -9 h is rather far into the forecast but note differences do appear between the forecasts...not clear which one is better for this case.



Comparison of RUC forecast soundings for Detroit at 0000 UTC – 12 h forecasts.


RUC forecast soundings vs RAOBs – 0000 UTC 23 Aug 05

Quite a bit of low level moisture MI-MN with extensive low clouds over MI.


RUC forecast soundings vs RAOBs – 0000 UTC 23 Aug 05

TAMDAR data available for 2300-0100 UTC, approximating what was available for the RUC 0000 UTC runs.


RUC analyses with and without TAMDAR for 0000 UTC 23 Aug

Comparison with the Detroit 0000 UTC raob. RH differences exist between the RUC analyses but dev2 (with TAMDAR) does not look as good as dev1 (RUC analysis without TAMDAR) for this site.



Comparison with the Minneapolis 0000 UTC raob. This time dev2 (with TAMDAR) looks better at lower levels.



Comparison with the Davenport Iowa 0000 UTC raob. Dev2 (with TAMDAR) temperature looks better at and above 850 mb.



Comparison with the Peoria Illinois 0000 UTC raob. No improvement seen for this site, but there are much fewer flights into PIA.


RUC 6h forecasts with and without TAMDAR for 0000 UTC 23 Aug

Comparison of 6h RUC forecasts with the Detroit 0000 UTC raob. Mixed results, down low dev (w/o TAMDAR) looks best with T, but above ~850 mb dev2 (with TAMDAR) closely matches the raob in T and Td.



Comparison with the MSP 0000 UTC raob. Less differences in the forecasts.



Comparison with the Green Bay 0000 UTC raob. Mixed...T better, RH not, for dev2 (with TAMDAR).



Comparison with the Peoria 0000 UTC raob. Little difference between the 2 forecasts aob 800 mb, but better RH with dev2 above this level.



Quiet weather aloft but still lots of low level moisture, especially eastern WI through MI.



TAMDAR flights before 1200 UTC.



For Detroit. Not much difference down low, but aob 750 mb dev2 RH better.



MSP shown here...much better temperature for dev2 in the lowest 100 mb.



Not true though at PIA, but again less TAMDAR here.



The same type of example for 12z from MSP; could argue that dev2 is a better analysis.



Analyses for Detroit.


RUC analyses with and without TAMDAR for 0000 UTC 24 Aug Analyses for MSP


RUC forecasts without TAMDAR for Detroit for 0000 UTC 24 Aug 3 and 6 h forecasts for Detroit. Improvement with time around 800 mb but not lower down.


RUC forecasts with TAMDAR for Detroit for 0000 UTC 24 Aug Dev2 forecasts more consistent.


RUC forecasts without TAMDAR for MSP at 0000 UTC 24 Aug


RUC forecasts with TAMDAR for MSP valid at 0000 UTC 24 Aug


RUC forecasts with and without TAMDAR for 0000 UTC 24 Aug Comparing the two 3-h forecasts. Note the great match from dev2 for lower level T but dev is better for Td.


RUC analyses with and without TAMDAR for 1200 UTC 24 Aug Still lots of lower level moisture around.


~TAMDAR availability for the 1200 UTC 24 Aug RUC



Analyses for Detroit. Much better moisture down low with TAMDAR.



Analyses for MSP. Dev2 with TAMDAR captures the low level inversion better.


Case study of potential forecast value of TAMDAR soundings -rapidly evolving environment in the Dakotas leading to tornadoes


Radar overview – 1900 UTC


TAMDAR availability: area is at the western edge of flights.


BIS RAOBs – the day starts with VERY shallow moisture but increasing southerly flow above the surface.

A lot happens before the next raob at 0000 UTC to set up a supercell environment - what did TAMDAR show?


ABR RAOB with 1301 and 1326 UTC TAMDARs

Note the increase in moisture just after the sounding launch and the increasing low level southerly flow.


ABR TAMDARs from 1533 to 1938 UTC.

This Aberdeen TAMDAR series of soundings nicely shows the increasing depth of low-level moisture even as the boundary layer warms.


GFK TAMDARs from 1705 to 1913 UTC.

Grand Forks TAMDAR series of soundings also shows the increasing depth of low-level moisture.


GFK CAPE/CIN for TAMDARs from 1705 vs. 1913 UTC.

Considerably less inhibition and more CAPE in just 2 h as shown by the TAMDAR soundings.


Environmental variability within the spacing of the raob network

Huge amount of variability on this day.


Overall Summary

● TAMDAR quality has improved since our last meeting● This allows forecasters to have more confidence in using the

data● Showing impact of TAMDAR on RUC forecasts is tricky

● But is fairly clear that one can see the impact on the analyses● Would like to look more at < 3 h forecasts

● It is easier to find examples of how TAMDAR data can aid operational forecasting and these can be quite dramatic● Compared with “smaller” effects in NWP models.

boulder tamdar meeting - ed szoke 1 august 25, 2005 ruc – raob – tamdar soundings ed szoke* noaa...

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