Alert archive / California / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 18, NWS Medford, OR

July 22, 1998Siskiyou County, California

NWS Medford, OR issued this severe thunderstorm warning at Jul 22, 1998, 5:35 PM PDT for Siskiyou County, California. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 22, 1998, 5:35 PM PDT (00:35 UTC)
Expired
Jul 22, 1998, 6:25 PM PDT
In force
50 min
Issued by
NWS Medford, OR
Area
Whole counties

County Siskiyou County, CA

The nearest sounding before it

Medford/Jackson, OR (KMFR), launched 00:00Z, 0.6 hours before the alert went out and 89 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.

Skew-T log-pSkew-T log-p diagram, Medford/Jackson, OR at 00:00Z on 1998-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1074 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 00:00Z on 1998-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1074 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
2426 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Jul 22, 2:30 PM PDT, 3 hours 5 minutes earlier.

Area forecast discussion, Jul 22, 2:30 PM PDT, 3 hours 5 minutes before
SOUTHWEST OREGON/NORTHEAST CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
230 PM PDT WED JUL 22 1998

INTRUSTION OF MONSOONAL MOISTURE WILL INCREASE THREAT OF TSTMS OVER
THE NEXT FEW DAYS.  INCREASINGLY SSE FLOW BETWEEN THE GREAT BASIN
HIGH AND WEAK TROUGH PATTERN ALONG THE WEST COAST WILL BRING
SCATTERED TSTMS TO SC ORE/NERN CA AND POSSIBLY INTO THE ROGUE BASIN.
AMPLE LOW LEVEL MOISTURE IN PLACE WITH DEW POINTS THIS AFTN ARND 60
DEG C FROM SHASTA VALLEY NWD INTO ROGUE AND KLAMATH BASINS.
CONVECTION BEGINNING AT TO FIRE AT 21Z ON LEADING EDGE OF DEBRIS
CLOUDS AND HEAD OF MOISTURE PLUME MVG INTO NRN CA/NWRN NV. CONCERNS
WILL SHIFT TO FLASH FLOOD POTENTIAL OVER NEXT COUPLE OF DAYS DUE TO
MOISTENING AIRMASS AND LIGHT STEERING CURRENTS.  COAST WILL REMAIN
UNDER INFLUENCE OF MARINE LAYER. JUST MINOR COOLING WITH INCREASE IN
CLOUDS AND TSTM ACTIVITY. NO MAJOR CHANGES INTO THE WEEKEND AS LARGE
SCALE PATTERN CHANGES LITTLE.   FOSTER

KMFR...NONE

.KMAX...VCP 21

...SEE PDXCCFPDX FOR CODED CITIES FORECAST

MFR UU 066/098 066/097 066 101222
LMT BB 060/093 059/093 058 103443
RBG UU 061/091 061/091 061 101111
4BK BB 055/066 055/064 055 100000
OTH BB 056/065 056/065 056 100000
YKA UU 061/098 060/098 059 102443
MHS BB 059/089 059/089 058 103443
S11 BB 056/093 057/093 056 103443

The office that day

Everything else NWS Medford, OR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 22, 6:56 PM PDTSevere Thunderstorm WarningMFRKlamath59 min
Jul 22, 8:54 PM PDTSevere Thunderstorm WarningMFRKlamath46 min
Jul 22, 6:15 PM PDTFlash Flood WarningMFRSiskiyou4 hr
Jul 22, 6:42 PM PDTSevere Thunderstorm WarningMFRSiskiyou48 min

Nearby

Severe Thunderstorm Warnings in California, 1998Every severe thunderstorm warning in 1998

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.