Forecasters: (NWS) and Morris Weisman (NCAR/MMM)
A surface cold front has proceeded well south of the STEPS domain this morning, lowering surface dew points to the mid-40s in eastern portions of the region to around 50 along the front range of Colorado. Soundings depict deep moisture within this airmass, with much mid-level cloudiness over the area this morning. Lapse rates, however, are fairly stable-to-neutral for moist adiabatic ascent. An upper-level wave and moist pool associated with the remnants of the hurricane that decayed west of Baja is located over eastern Utah and western Colorado this morning. This system is forecast to propagate eastward over the STEPS region by late afternoon and evening. With some surface heating, widespread showers and thundershowers are expected to develop along the Front Range by early afternoon, and propagate over the STEPS region by late today. Significant rainfall could occur with this system, but severe weather is unlikely. Shear magnitudes are fairly strong today, but the lack of CAPE will preclude supercell development.
The surface flow is forecast to become strong from the southeast tonight and tomorrow, returning significant low-level moisture and instability into the STEPS region by tomorrow afternoon. Shear magnitudes will be sufficient for supercellular activity and upper level waves propagating into the region from the NW along with upslope conditions along the Front Range will offer ample forcing for convective initiation. Severe convection will be likely within the research domain.
Shear and instability conditions remain favorable for Wednesday, with significant convection, possibly supercellular, again likely.
| VARIABLE | Day 1: 1-4 pm | Day 1: 4-9 pm | Day 2 | Day 3 |
|---|---|---|---|---|
| Convective Potential |
0.5 | 1 | 2 | 2 |
| Storm Type | 2 | 2 | 3 | 3 |
| Triggering | 1 | 1 | 2 | 2 |
| Intuition | -1 | -1 | 0 | 0 |
| Total | 2.5 | 3 | 7 | 7 |
| SYSTEM | STATUS |
|---|---|
| Ops Center | Operational. |
| CHILL | Operational. |
| S-Pol | Operational. |
| LMA | Operational. |
| MGLASS | Operational. About 40 MGLASS soundings remain, which, if we limit to a maximum of four per case (e.g., 19-20 UTC and 00 UTC), will cover up to 10 more cases. |
| T-28 | Operational. |
| Storm ballooning | Operational, but only seven EFMs remain with the possibility of refurbishing a few more. |
| Mobile mesonet | Four vehicles are available. |
| Storm chase van | Operational as the primary precipitation verification vehicle. |
| YRFS | Operational. |
| NWS | Operational. |
Coordinated STEPS observations have been called down for today. CHILL will be conducting horn tests this morning. CHILL and S-Pol may coordinate with the two DOWs this afternoon to sample the more stratiform precipitation forecast for later today. S-Pol (Charlie Knight) will also plan to scan showers and clouds of opportunity during the day.
Day was called down. No STEPS-related operations were conducted. The DOWs apparently did some coordinated scans with S-Pol. CHILL was involved in polarization and feed horn tests.