1. Overview of USWRP’s International H2O Project (IHOP_2002)
David B. Parsons and Tammy Weckwerth
NCAR/ATD
IHOP facts and research goals
Preliminary highlights
Modeling plans

2. IHOP_2002 Hypothesis
Improved measurements of water vapor will lead to a corresponding improvement in our ability to predict convective rainfall amounts.
Note: 0-12 h forecasts in an environment where the dyamics is well characterized.

3. Isentrophic Airflow and IHOP Sounding Domain
Isentropic streamlines (37 C) for 2330 UTC 4 May The dashed lines are
isobars at 100 hPa intervals (from Carlson and Ludlam 1968)

4. Some Research Goals Directly Relevant to QPF
Improved understanding and prediction of convective onset.
Determine the degree of improvement in forecast skill that occurs through improved characterization of the water vapor field (0-6/12 h) in an environment where the dynamics are relatively well captured.
Improved understanding and treatment of the relationship between atmospheric water vapor, soil moisture, surface fluxes and boundary layer processes.
Improved assimilation of water vapor measurements for warm season events (including satellite data).
Determine the future optimal mix of satellite, ground-based and surface water vapor measurement strategies for warm season rainfall.

5. IHOP Summary: 13 May to 25 June
>200 Investigators and technical participants
~2500 additional soundings
> 50 instrument platforms, 6 aircraft, 36 IOPs
268 h of airborne water vapor lidar measurements
76 h of airborne satellite evaluation measurements (S-HIS and NAST)
Dedicated GOES-11 data

6. S-Pol Refractivity Retrieval
variations in q, T and p
boundary detection
advection
QPF, CI, ABL and inst
Lower ABL
dryline
dryline
warm/dry
cool/moist

7. Refractivity: One Day After Heavy Rainfall Aircraft In-situ data
N: Ts=45,Theta60=307, q60 = 8.5
S: Ts=32,Theta60=306.2, q60 = 11

8. Evolution
of the dryline

9. Nocturnal Convection
An example of
a nocturnal
undular bore

10. Example of a Nocturnal Undular Bore
Doppler Velocity
Example of a Nocturnal Undular Bore
Bores were a common feature in the nocturnal environment over the western great plains. They are important for QPF studies as they change the depth of the moisture and the strength of the capping inversion.

11. Bore Example (Radar RHI)

12. BORE
Example
From
MAPR
4 June

13. Water Vapor: 20 June

14. From Trier et al. 2002, abstract 130
Sounding Susceptible to PBL-Based Convection
Sounding Susceptible to Elevated Convection
DVN (0000 UTC 9/12/2000)
GRB (0000 UTC 9/12/2000)
From Trier et al. 2002, abstract 130

15. Convective
Initiation
of a flash
flood

16. Some Closing Thoughts
Some spectacular convective initiation cases, but often highly dependent on forecaster refinement of model output. Also many null cases (50-50?).
Nocturnal convection is far different than previously thought (bores and jet decoupling).
Potential utility of radar refractivity and high resolution radar composites.
Water vapor vertical cross-sections useful for determining changes in capping inversions for forecasters. (SPC forecaster comment)
Spaced antenna profilers can easily detect intense mesoscale air motions.
Scientist/forecaster interactions were extremely valuable.
Modeling work has only just begun.

17. Model, Assimilation and Nowcasting Efforts2
10-km version of the ETA model (Gallus/U of Iowa)
ARPS non-hydrostatic model1 (Carr et al./CAPS-OU)
Operational RUC (Szoke & Brown et al./NOAA/FSL)
LAPS with MM5 & WRF (Koch et al./NOAA/FSL)
Non-hydrostatic CSU RAMS (Zeigler/NOAA/NSSL)
UW NMS (Mecikalski/UW)
MM5 mesoscale model (Lapenta/GSFC; Mecikalski/UW; Pinto et al./NCAR)
WRF mesoscale model (NCAR)
CRAS mesoscale model (Diak/UW & Davis/Penn State)
Interactive flash flood analyzer and rainfall autonowcaster (Holt et al./NOAA/NESDIS)
NCAR autonowcaster (Wilson et al./NCAR)
NCAR Water Cycle Initiative Group (Cloud model to Community climate model scales)
ETA/WRF NCEP mesoscale branch (after data is cleaned up)
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1These efforts may move to the WRF model during the post-field phase.
2The research includes evaluation of current products, assimilation research, forecasting, and predictability studies.