Alert archive / Oregon / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 5, NWS Portland, OR

July 13, 2004Linn County, Marion County, Oregon

NWS Portland, OR issued this severe thunderstorm warning at Jul 13, 2004, 1:39 AM PDT for Linn County, Marion County, Oregon. It was in force for 36 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 13, 2004, 1:39 AM PDT (08:39 UTC)
Expired: Jul 13, 2004, 2:15 AM PDT
In force: 36 min
Issued by: NWS Portland, OR
Area: Counties, with a storm outline in the text

Counties Linn County, OR, Marion County, OR

The radar

The Portland,OR radar (KRTX), 118 km from the middle of the area, began a volume at 08:39 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.

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 Portland, OR wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 12, 9:00 PM PDT, 4 hours 39 minutes earlier.

Area forecast discussion, Jul 12, 9:00 PM PDT, 4 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
900 PM PDT MON JUL 12 2004

.SYNOPSIS...A SURFACE TROUGH OF LOW PRESSURE CURRENTLY OVER WESTERN
OREGON WILL SHIFT E OF THE CASCADES TONIGHT TURNING THE LOW LEVEL
FLOW ONSHORE. AN UPPER LEVEL LOW OFFSHORE WILL KEEP THE UPPER LEVEL
FLOW OUT OF THE S...WITH SEVERAL WEAK DISTURBANCES LIFTING N THROUGH
THE REGION OVER THE NEXT FEW DAYS. BY THE WEEKEND...THE UPPER TROUGH
WILL SHIFT E TOWARDS THE COAST.
&&

.DISCUSSION
SHORT TERM...DOPPLER RADAR INDICATED A FEW TSTM CELLS OVER THE
CENTRAL CASCADES EARLIER THIS EVENING THAT HAVE WEAKENED AND MOVED
NORTHEAST OUT OF THE CWA. AT 0240Z THE RADAR SHOWED SOME NEW CELLS
DEVELOPING EAST OF SALEM AND CORVALLIS MOVING NORTH INTO THE
WILLAMETTE VALLEY. THE 00Z MESO ETA AND GFS SUPPORT THIS CONVECTIVE
ACTIVITY IN ASSOCIATION WITH A SHORTWAVE MOVING NORTH OVERNIGHT...AND
EVEN EXTEND THE AREA NORTHWEST INTO THE LOWER COLUMBIA TILL AT LEAST
12Z. WILL UPDATE THE ZONES TO INCLUDE A SLIGHT CHANCE OF TSTMS TILL
12Z...AT WHICH TIME THE ONSHORE PUSH SHOULD START DAMPENING THE
CONVECTIVE ACTIVITY. LOW CLOUDS HAVE MOVED N ALONG THE COAST PAST
NEWPORT AND METARS INDICATE ONSHORE FLOW HAS BEGUN OVER SW PART OF
FORECAST AREA. AS THE THERMAL INDUCED TROUGH SHIFTS E OVERNIGHT...A
GOOD SW MARINE PUSH SHOULD ENSUE. MARINE PUSH WILL STABILIZE AND COOL
AIR MASS IN AREAS W  OF THE CASCADES FOR TUE...WHILE SOUTHERLY UPPER
LEVEL FLOW WITH WEAK SHORTWAVES LIFTING N WILL KEEP A SLIGHT CHANCE
FOR CONVECTION OVER THE CASCADES GOING TUE AND WED. AS UPPER LEVEL
FLOW PICKS UP MORE OF A WESTERLY COMPONENT...CONVECTIVE POTENTIAL
SHOULD SHIFT E OF FORECAST AREA THU. WITH DEEPENING MARINE AIR
OVERNIGHT AND A SHORTWAVE LIFTING THROUGH...EXPECT SOME FOG AND
DRIZZLE LATER TONIGHT OVER COASTAL REGIONS. LIKENS

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...EXTENDED
MODELS TENDING TOWARDS THE GFS SOLUTION OF SHIFTING THE LONGWAVE
TROUGH E TOWARDS THE FORECAST AREA. SEE NO REASON TO CHANGE AWAY FROM
THE CURRENT FORECAST WHICH HAS SMALL CHANCES FOR SHOWERS...WITH THE
BEST CHANCES ON THE N COAST.

.PRELIMINARY POINT POPS
AST 221122 PDX 21111- SLE 21111- EUG 1111--
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
.OR/WA...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 13, 2:43 AM PDT	Severe Thunderstorm Warning	PQR	Clackamas, Marion	32 min
Jul 13, 3:14 AM PDT	Severe Thunderstorm Warning	PQR	Clackamas	31 min

Nearby

Severe Thunderstorm Warnings in Oregon, 2004 Every severe thunderstorm warning in 2004

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.