Alert archive / California / Frost Advisories in 2017
Frost Advisory 15, NWS Medford, OR
NWS Medford, OR issued this frost advisory at Sep 21, 2017, 12:51 PM PDT for Klamath County, Oregon; Modoc County, Siskiyou County, California. It took effect at Sep 23, 2017, 2:00 AM PDT. It was in force for 7 hr.
The area
The counties it named.
The facts
- Issued
- Sep 21, 2017, 12:51 PM PDT (19:51 UTC)
- In effect from
- Sep 23, 2017, 2:00 AM PDT
- Expired
- Sep 23, 2017, 9:00 AM PDT
- In force
- 7 hr
- Issued by
- NWS Medford, OR
Counties Modoc County, CA, Siskiyou County, CA, Klamath County, OR
The radar
The Medford radar (KMAX), 90 km from the middle of the area, began a volume at 19:49 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Medford/Jackson, OR (KMFR), launched 12:00Z, 7.9 hours before the alert went out and 106 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 17 J/kg
- Mixed-layer CIN
- -8 J/kg
- Mixed-layer LCL
- 677 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 39 m²/s²
- 0-3 km storm-relative helicity
- 69 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this frost advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Medford, OR wrote its last area forecast discussion before this frost advisory went out at Sep 20, 2:45 PM PDT, 22 hours 6 minutes earlier.
Area forecast discussion, Sep 20, 2:45 PM PDT, 22 hours 6 minutes before
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</html>The office that day
Everything else NWS Medford, OR issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 21, 12:51 PM PDT | Freeze Watch | MFR | Klamath | 14 hr |
Nearby
Frost Advisories in California, 2017Frost Advisories in Oregon, 2017Every frost advisory in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.