Forecasters: (NWS) and Morris Weisman (NCAR/MMM)
Today:
Low-level moisture values have increased significantly overnight, with surface dewpoints ranging from the mid 50's on the western edge of the domain to mid-to-upper 60's on the eastern edge. Surface flow is generally southerly at 10-15 kts, with a southwesterly tendency to the west and a more southeasterly tendency to the east. The moisture gradient is expected to consolidate into a dry line by early afternoon, located near the center of the STEPS domain. East of the dry line, CAPEs may exceed 2000 j/kg, while west of the dry line CAPES will drop to 500-1000 j/kg.
A weak upper-level disturbance over central Wyoming and northwest Colorado is also evident on the satellite this morning, and is forecast to pass over the STEPS domain late this afternoon and evening. Convection is expected to develop along the dry line by late afternoon, first to the north-northwest of the STEPS region, but developing further southeast into the northern STEPS regions by early evening. Shear values are expected to be between 30 and 40 kts between the surface and 500 mb, which is minimal for supercellular activity, but severe storms cannot be ruled out. Strong surface winds and hail up to 1 inch will be possible with these storms.
Days 2 and 3:
For tomorrow and Monday, surface moisture is forecast to push further eastward, with upper-level heights rising and shear values decreasing. Hot and dry conditions are expected, with little chance for significant convection.
Note:
Because of poor weather conditions anticipated for the next few days, operations have been called down for Sunday 7/2 and Monday 7/3. A weather briefing/discussion will be disseminated electronically mid-morning Monday that will either call for a normal Ops meeting at 9am on Tuesday in advance of expected storms, or extend the down period through Tuesday, the 4th of July. Regardless of the outcome for Tuesday, a 9am briefing will definitely be held on Wednesday, July 5th.
STEPS project personnel are encouraged to consult the STEPS web page for the decision regarding whether or not there will be a Tuesday AM briefing.
| VARIABLE | Day 1: 1-4 pm | Day 1: 4-9 pm | Day 2 | Day 3 |
|---|---|---|---|---|
| Convective Potential |
2 | 2.5 | 1.5 | 1 |
| Storm Type | 1 | 2 | 1 | 1 |
| Triggering | 1 | 2 | 1 | 1 |
| Intuition | 0 | 0 | 0 | 0 |
| Total | 4 | 6.5 | 3.5 | 3 |
| SYSTEM | STATUS |
|---|---|
| Ops Center | Operational. |
| CHILL | Operational. |
| S-Pol | Operational. |
| LMA | Operational. |
| MGLASS | Operational. Prior to any soundings today, there are 21 remaining sondes. |
| T-28 | Engine failure, no longer available to the project. |
| Storm ballooning | Operational. There are 6 EFMs available. |
| Mobile mesonet | Recalled to Norman, no longer available to the project. |
| Storm chase van | Operational as the primary precipitation verification vehicle. |
| YRFS | Operational. |
| NWS | Operational. |
Forecast warrants standby for possible late afternoon and evening convection. Radars will come up at 1:30 PM. NSSL5 to standby at 2 PM for possible operations. NSSL5 will broaden spectrum of storms to be sampled to include non-severe since they have roughly 1 week to go and ample EFM's. MGLASS soundings will be taken at Goodland and Flagler at 18 UTC, with a possibility for additional launches later in the day.
At 2145Z, we are still waiting for storms along a well-defined boundary to our west and northwest. New echoes started appearing along this boundary about 2240Z, with a few lightning flashes as reported by the LMA. Numerous narrow cells along this NE-SW line are showing very little lightning activity.
At 2342Z, NSSL5 dispatched to north of Wray for a possible anvil launch, but the EFM was never launched. Secured operations around 0015Z, July 2.