Date: 17 Apr 05:30 AM
Votes: Good: 8 Bad: 1 Abstain: 1
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Apr 17 12:23 PM | iem,main | ⬆️ Update ruff | Link |
| Apr 17 12:30 PM | iem,main | 📝 Sundry updates per review | Link |
| Apr 17 10:35 PM | iem,main | ✨ Add bling to NWS Emergencies Map https://mesonet.agron.iastate.edu/vtec/emergencies.php |
Link |
| Apr 17 10:47 PM | iem,main | 🐛 Fix summary calc | Link |
| Apr 17 9:06 AM | pyiem,main | 🎨 Catch a pattern match failure for CWA parsing | Link |
| Apr 17 9:07 AM | pyiem,main | ⚡️ Prevent un-needed ugc dbload | Link |
| Apr 17 9:08 AM | pyiem,main | ⬆️ Update ruff | Link |
| Apr 17 10:58 PM | iemone,main | 🐛 Refresh warnings layer | Link |
| Apr 17 12:15 PM | iem-web-services,main | ⬆️ Update ruff | Link |
| Apr 17 12:18 PM | iem-web-services,main | 🐛 Shim VTWAC to other database, for now | Link |
SPC MCD Watch Probability
Date: 17 Apr 05:30 AM
Votes: Good: 8
Bad: 1 Abstain: 1
Iowa is forecast to have a chance of severe weather today and into the overnight hours. As the event unfolds, the Storm Prediction Center (SPC) issues Mesoscale Convective Discussions (MCD)s [example MCD text] that provide up to the minute forecast details and thinking from the experts at the SPC. The MCD product sometimes portends an upcoming Tornado or Severe Thunderstorm Watch. As a part of that process, the MCD will contain a watch issuance probability (a fixed percentage value of 5, 20, 40, 60, 80, or 95 percent). So the featured chart compares this forecast value to if a watch was issued in the near term future (within 2.5 hours) for a spatially coincident area outlined by the MCD. The archive for this probability exists back to 2012 and there's an IEM portal to download the archive. Remarkably, the 60, 80, and 95 percent thresholds seem in high agreement with only a few percentage points difference between the two. The 20 percent threshold may be suffering from this arbitrary time and space threshold combination or maybe it is not well calibrated, this crude and unofficial IEM analysis wishes not to state anything absolutely.
| Summary | By WFO | Watches | ||||||
|---|---|---|---|---|---|---|---|---|
| Type | US | IA | ARX | DVN | DMX | OAX | FSD | US |
| Tornado | 12 | 10 | 0 | 0 | 2 | 10 | 0 | 1 |
| Svr Tstorm | 43 | 19 | 0 | 0 | 11 | 10 | 3 | 1 |
| Flash Flood | 0 | 0 | 0 | 0 | 0 | 0 | 0 | --- |
ARX = LaCrosse, WI DVN = Davenport, IA DMX = Des Moines, IA OAX = Omaha, NE FSD = Sioux Falls, SD
SVR+TOR Warnings Issued: 53 Verified: 31 [58.5%] Polygon Size Versus County Size [30.6%] Average Perimeter Ratio [25.0%] Percentage of Warned Area Verified (15km) [34.5%] Average Storm Based Warning Size [1354 sq km] Probability of Detection(higher is better) [0.79] False Alarm Ratio (lower is better) [0.42] Critical Success Index (higher is better) [0.51]