TAMDAR Workshop 2006 – Boulder, Colorado 1 April 13, 2006 UPDATE ON TAMDAR IMPACT ON RUC FORECASTS & RECENT TAMDAR/RAOB COMPARISONS Ed Szoke,* Brian Jamison*,

TAMDAR Workshop 2006 – Boulder, Colorado1April 13, 2006

UPDATE ON TAMDAR IMPACT ON RUC FORECASTS

& RECENT TAMDAR/RAOB COMPARISONS

Ed Szoke,* Brian Jamison*, Bill Moninger, Stan Benjamin,Randy Collander*, and Tracy Smith*

NOAA/ESRL Global Systems Division

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


Outline

Using the high-resolution TAMDAR data available since 30 Mar 06... Examine impact on RUC forecasts

Subjective evaluation concentrating on short-range precipitation forecasts

Focus on 6-h accumulated precipitation forecasts ending at 0000 and 0600 UTC (but other fields also examined)

For 1800 UTC runs compare forecast soundings with observed soundings Models used: identical RUC-20 km runs with and without TAMDAR

Compare TAMDAR sounding quality and detail TAMDAR soundings compared to each other TAMDAR soundings compared to nearby RAOBs

Emphasis on the kinds of sharp structures that can be resolved with the higher resolution TAMDAR data


30 Mar 2100 UTC: Deepening storm with severe weather & ND snow

System is atnorth/westedge of TAMDAR towithin network(in WI/IL).In ND rain changing to snow. Willexamine precipitationfields and CAPE and helicity.


Display of the TAMDAR coverage from 2100 UTC 30 Mar to 0000 UTC 31 Mar


TAMDAR/RAOB comparisons for 0000 UTC 31 Mar 06 – Minneapolis

Good overall agreement with the sounding and all TAMDARs nicely resolve thedry layer centered at 800 mb


TAMDAR/RAOB comparisons for 0000 UTC 31 Mar 06 – Minneapolis

The most variability in thisset is from the flight heading offto the southeast.


AMDAR/RAOB comparisons for 0000 UTC 31 Mar 06 – Minneapolis

For comparison toTAMDAR, here are a few AMDARtemperature profiles comparedto the MSP RAOB


TAMDAR/RAOB comparisons for 0000 UTC 31 Mar 06 – Peoria, Illinois

Here we do see adifference between the ascentand descentsoundings (thattrack in pretty much the same location and notfar off in time), with a better match to the RAOB for the TAMDAR ascent.


7 April 0000 UTC: Deepening storm with severe weather & R+

High risk severe wx dayNE to easternKS. Also heavy rains in band e-w across MSP.Will examine precipitationfields and CAPE and helicity.


Comparison of 6-h RUC precipitation forecasts with and without TAMDAR for runs initialized at 1800 UTC on 6 April 06.

Two main differences are highlighted: 1) In MN/nrn IA with more precip in TAMDAR run 2) More of a line of precip in eastern NE in the TAMDAR run

Without TAMDAR With TAMDAR

>0.25” >0.5” >1.0”>0.10”


Observed 6h precipitation ending 0000 UTC 7 April 06

TAMDAR run looks better for having more precip near MSP.

Similarly, in easternKS more precipin the TAMDAR run is also better.


Comparison of 6-h RUC CAPE and CIN forecasts with and without TAMDAR for runs initialized at 1800 UTC on 6 April 06.

Not a lot of differences in the CAPE fields although more CIN across IL in the TAMDAR run.

Without TAMDAR With TAMDAR


Analyzed CAPE from the NAM valid 0000 UTC 7 April 06


Comparison of 6-h RUC Helicity forecasts with and without TAMDAR for runs initialized at 1800 UTC on 6 April 06.

A few differences are seen (northern IA, eastern KY). Analysis (next) perhaps favors TAMDAR runslightly....

Without TAMDARWith TAMDAR


Analyzed SREH from the NAM valid 0000 UTC 7 April 06


6 April 1800 UTC: Storm intensifying with severe weather developing

Next we'll examine someTAMDAR/RAOB comparisonsfor 1200 UTCand for thespecial soundingslaunched at 1800 UTC for MSP andLZK (LittleRock, AR).


TAMDAR/RAOB comparisons for 1200 UTC 6 April 06 – Minneapolis

Good agreement between the twodescent TAMDARs



Same with this set



Also good agreement with a descent/ascentpair.



The main disagreement isfound for the 2 TAMDARs heading south, but note these are ~80 minapart in time.


TAMDAR/RAOB comparisons for Minneapolis: time series

Nice depiction ofthe effect of sustained lift on the strong inversion centered near 850 mb.


TAMDAR/RAOB comparisons for 1200 UTC 6 April 06 – Little Rock/Nashville

Good overall agreement with the sounding and all TAMDARs.



Note how well the sharp inversionis resolved near900 mb, and the very sharp dry layer above this.



Similar goodresolution with this set of soundings a littlewhile later.


TAMDAR coverage for 1500-1800 UTC 6 April 06

Coverage doesn't go quite to LittleRock but is close.


The next day: 7 April 2100 UTC - Severe weather moves into eastern/southern part of TAMDAR network

Another highrisk day, this timeshifted east to western TN/KY.By 2100 UTC 4tornado watch boxes were already in place.


Southern TAMDAR coverage for 7 April 06

Jackson

Little Rock

BNA


Comparison of 6-h RUC precipitation forecasts with and without TAMDAR for runs initialized at 1800 UTC on 7 April 06.

More precipitation is produced by the run with TAMDAR across southern IN into OH. The run without TAMDAR has more precip in nw AL.

Without TAMDARWith TAMDAR

>0.25” >0.5” >1.0”>0.10”


Observed 6h precipitation ending 0000 UTC 8 April 06

TAMDAR run looks better for having more precip in IN/OH


TAMDAR/RAOB comparisons for 1200 UTC 7 Apr 06 – Jackson, MS

Sharp dry layerabove the inversion is really captured well.


TAMDAR/RAOB comparisons for ~1500-1800 UTC 7 Apr 06 – Jackson, MS

Sharp moisture changes between700 to 750 mbare shown in special RAOBs and TAMDARs.Also, good agreement withthe moisture profile down low.


TAMDAR time series for Memphis leading up to initial tornadoes

Nice time seriesshowing both theremoval of the early morning capnear 850 mb andthen the development of amuch more moistand unstable layerin the lowest 100 mb.


Summary

RUC forecasts with and without TAMDAR showed some differences Generally did not find cases as dramatic as those shown at AMS

But the differences that were found usually favored the TAMDAR runs For other cases recently (not shown) differences were minor

Sounding comparisons... Showed 3 different strong severe weather days

Overall consistency between TAMDAR soundings is fairly good Higher resolution data is able to nicely capture very sharp moist/dry layers TAMDAR soundings continue to show value for forecast applications

Nice Memphis time series leading up to the initial TN tornadoes last Friday

Documents

TAMDAR Workshop 2006 – Boulder, Colorado 1 April 13, 2006 UPDATE ON TAMDAR IMPACT ON RUC FORECASTS & RECENT TAMDAR/RAOB COMPARISONS Ed Szoke,* Brian Jamison*,