Severe Thunderstorm Warning 27, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
307 PM PDT MON AUG 12 2013

.DISCUSSION...
VISIBLE SATELLITE IMAGERY AND KMAX RADAR RETURNS OVER THE LAST
HOUR INDICATE THAT SURFACE BASED CONVECTION IS BEGINNING TO
INITIATE ACROSS THE AREA. AT THE CURRENT TIME AREAS OF FOCUS
ARE CENTRAL SISKIYOU COUNTY, NORTH AND EASTERN LAKE COUNTY, AND
THE CASCADES NORTH-NORTHEAST OF CRATER LAKE NATIONAL PARK. WATER
VAPOR IMAGERY ALSO INDICATES THE UPPER LEVEL LOW PRESSURE WAVE
EXPECTED TO AID IN CONVECTIVE DEVELOPMENT ROTATING THROUGH
NORTHERN CALIFORNIA OUT INTO KLAMATH AND LAKE COUNTIES AT THE
CURRENT TIME. THIS IS CONSISTENT WITH MODEL GUIDANCE, AS WELL.
SPC MESOSCALE ANALYSIS INDICATES MOST UNSTABLE CAPE INCREASING
UNDER THIS WAVE, WEST OF THE PRIMARY CLOUD SHIELD ON THE EAST
SIDE. ADDITIONALLY, FAVORABLE OMEGA IS PUSHING OUT OF NORTHERN
CALIFORNIA AND INTO SOUTHERN OREGON AT THIS TIME. THUS, THE RED
FLAG WARNING FOR LIGHTNING ON THE EAST SIDE LOOKS ON TRACK AT THIS
TIME. DO HAVE SOME CONCERN THAT THE ACTIVITY IN NORTHERN
CALIFORNIA COULD GET A LITTLE BEYOND ISOLATED SHOULD CONVECTION
ORGANIZE THERE BEFORE ABOUT 00Z. THE PRIMARY THREAT FROM THESE
THUNDERSTORMS WILL BE MOSTLY DRY LIGHTNING. ANY HAIL SHOULD BE
SMALL AND WINDS SUB-SEVERE. RAINFALL WILL BE BRIEF DUE TO STEADY
SW TO NE 15-25KT STEERING FLOW.

ASIDE FROM THUNDERSTORMS THIS AFTERNOON AND EVENING ARE AREAS OF
SMOKE AND THE MARINE LAYER. PER SATELLITE, THE FIRES THAT REMAIN
ACTIVE ENOUGH TO BE A SMOKE PROBLEM ARE THE WHISKEY COMPLEX EAST
OF TILLER AND THE ORLEANS AND SALMON COMPLEXES IN NW CALIFORNIA.
HAVE ADDED AREAS OF SMOKE NEAR THESE FIRES AND ATTEMPTED TO
CAPTURE HAZE EFFECTS BEYOND SOURCES FOR OTHER LOCATIONS IN THE
FORECAST AREA FOR THE NEXT 48-60 HOURS. BEYOND THAT, WE WILL NEED
TO SEE HOW ACTIVE THESE FIRES ARE AND IF ANY OTHERS BECOME ACTIVE.
WITH WARM TO HOT AND DRY WEATHER EXPECTED TO CONTINUE, SUSPECT
FIRE AND SMOKE ACTIVITY WILL INCREASE ACROSS THE AREA. THE MARINE
LAYER TONIGHT THROUGH TUESDAY MORNING WILL AFFECT THE COASTLINE TO
ABOUT ROSEBURG OVERNIGHT. AS FAR AS ACTIVE FIRE PERIMETERS, EXPECT
MAIN EFFECTS TO BE ON THE DOUGLAS COMPLEX.

A WARMING AND DRYING TREND WILL PERSIST THROUGH WEDNESDAY BEFORE
A WEAKENING FRONTAL BOUNDARY ARRIVES THURSDAY INTO FRIDAY. EXPECT
THE MARINE LAYER INFLUENCE TO INCREASE DURING THIS TIME PERIOD,
AND THERE WILL BE A THREAT OF THUNDERSTORMS ON FRIDAY ALONG AND
NEAR THE MARBLE MOUNTAINS AND CASCADES.

THEREAFTER MODELS ARE ADVERTISING A BUILDING UPPER LEVEL HIGH FROM
THE FOUR CORNERS REGION. LONG TERM MODEL GUIDANCE SUGGESTS ABOVE
AVERAGE TEMPERATURES FOR THE MAJORITY OF WEEKS 2 AND 3. BTL

&&

.AVIATION...BASED ON THE 12/18Z TAF CYCLE.

MVFR CONDITIONS WILL CONTINUE INTO THE EARLY AFTERNOON ACROSS
PORTIONS OF THE UMPQUA BASIN BEFORE CLEARING. AREAS OF SMOKE APPEAR
TO BE OF MOST CONSEQUENCE EAST OF TILLER FROM THE WHISKEY COMPLEX
AND ACROSS WESTERN SISKIYOU COUNTY FROM THE ORLEANS AND SALMON RIVER
COMPLEXES. SOUTHWEST FLOW WILL PUSH THIS SMOKE OUT TO THE NORTHEAST
THIS AFTERNOON. DURING THE AFTERNOON INTO THE EVENING LOW PRESSURE
MOVING THROUGH ALOFT WILL ASSIST IN THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS FROM THE CASCADES, SISKIYOUS, AND MARBLE MOUNTAINS
EASTWARD, MOST NUMEROUS ACROSS KLAMATH AND LAKE COUNTIES. THESE
THUNDERSTORMS WILL BE CAPABLE OF GUSTY OUTFLOW WINDS, SIGNIFICANT
LIGHTNING, SMALL HAIL, AND LOCALIZED RAINFALL. OVERNIGHT EXPECT THE
MARINE LAYER TO RETURN ALONG THE COOS COUNTY COAST TO ABOUT ROSEBURG
IN THE IFR TO MVFR RANGE. BTL

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ027>031.

CA...NONE.

PACIFIC COASTAL WATERS...NONE.

BTL/NSK/FJB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEDFORD OR
545 PM PDT MON AUG 12 2013

CAZ083-084-130130-
NORTH CENTRAL AND SOUTHEAST SISKIYOU COUNTY CA-NORTHEAST SISKIYOU AND
NORTHWEST MODOC COUNTIES CA-
545 PM PDT MON AUG 12 2013

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN SISKIYOU COUNTY UNTIL 630
PM PDT...

AT 542 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES NORTH OF BRAY...OR 33 MILES NORTHEAST OF
MOUNT SHASTA...MOVING NORTHEAST AT 5 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER IS EXPECTED WITH THIS STORM...
ALONG WITH HEAVY RAIN.

AREAS AFFECTED BY THIS STORM INCLUDE...MACDOEL.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 4186 12199 4180 12181 4166 12195 4172 12208
TIME...MOT...LOC 0045Z 218DEG 6KT 4174 12198

FB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEDFORD OR
633 PM PDT MON AUG 12 2013

CAZ084-ORZ029-130215-
KLAMATH BASIN OR-NORTHEAST SISKIYOU AND NORTHWEST MODOC COUNTIES CA-
633 PM PDT MON AUG 12 2013

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN KLAMATH AND
NORTHEASTERN SISKIYOU COUNTIES UNTIL 715 PM PDT...

AT 629 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR DORRIS...OR 20 MILES SOUTHWEST OF KLAMATH
FALLS...MOVING NORTHEAST AT 10 MPH.

HAIL UP TO THE SIZE OF PENNIES IS EXPECTED WITH THIS STORM...ALONG
WITH FREQUENT LIGHTNING.

AREAS AFFECTED BY THIS STORM INCLUDE...DORRIS AND WORDEN. THE STORM
IS EXPECTED TO REMAIN WEST OF HIGHWAY 97.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

LAT...LON 4209 12203 4204 12183 4191 12189 4194 12211
TIME...MOT...LOC 0132Z 209DEG 7KT 4198 12198

FB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
658 PM PDT MON AUG 12 2013

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0647 PM     HAIL             6 W FORT ROCK           43.37N 121.16W
08/12/2013  E1.00 INCH       LAKE               OR   TRAINED SPOTTER

            LA113 SPOTTER, ONE INCH OR BETTER HAIL
            SPOTTED BETWEEN FORT ROCK AND HIGHWAY 31

&&

IRIS SYSTEM