Red Flag Warning 6, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
346 AM PDT FRI JUL 26 2013

.DISCUSSION...QUICK UPDATE TO TALK ABOUT THE THUNDERSTORMS GOING
ON OVER JOSEPHINE AND DOUGLAS COUNTIES THIS MORNING. THESE STORMS
SUDDENLY POPPED UP AND HAVE PRODUCED QUITE A BIT OF LIGHTNING THIS
MORNING...ALREADY OVER 200 STRIKES. LOOKING AT IR SATELLITE, IT
APPEARS THAT A BAND OF CLOUDS THAT LOOKED LIKE AN OUTFLOW BOUNDARY
FROM LAST EVENING'S CONVECTION OVER CALIFORNIA ROLLED INTO SW
OREGON AND LIT UP. THIS IS PERHAPS DUE TO A LITTLE ADDED
CONVEGENCE WITH THE INCOMING MARINE LAYER. BASED ON CURRENT TRENDS
IT LOOKS LIKE THIS WILL CONTINUE TO EDGE NORTHWARD OVER THE NEXT
FEW HOURS AND PROBABLY MOVE OUT OF OUR AREA BY DAWN. THE CONCERN
ABOUT THESE STORMS IS THAT THE LOW LEVELS ARE VERY DRY AND THE
CELLS ARE MOVING SO THEY AREN'T HAVING TIME TO MOISTEN UP THE
ATMOSPHERE...IN OTHER WORDS: THERE PROBABLY ISN'T MUCH RAIN
REACHING THE GROUND. WITH THE SHEAR NUMBER OF STRIKES ALREADY AND
THE FACT THAT FUELS ARE DRY AND THERE ISN'T LIKELY MUCH RAIN, WE
MAY SEE SOME FIRE STARTS. FURTHER, ONSHORE WINDS MAY GET BREEZY
THIS AFTERNOON WHICH WON'T HELP...AND IT WILL TAKE A WHILE FOR
HUMIDITIES TO GO UP. NEEDLESS TO SAY, FIRE CONCERNS ARE NOW
ELEVATED OVER FAR SW OREGON THIS MORNING. -WRIGHT

&&

.PREV DISCUSSION... /ISSUED 150 AM PDT FRI JUL 26 2013/

DISCUSSION...TEMPERATURES AT THE MEDFORD AIRPORT TOPPED OUT AT
106 DEGREES YESTERDAY WHICH WAS 1 DEGREE SHORT OF A RECORD FOR THE
DAY (107 FROM 1988). WE DID ACHIEVE NEW RECORD HIGHS IN ALTURAS,
CA (100) AND MONTAGUE, CA (102). NEEDLESS TO SAY, THAT WAS UNUSUAL
AND IT WILL ALSO BE QUITE HOT AGAIN TODAY. BUT THIS SHOULD BE THE
LAST DAY OF REALLY HOT WEATHER FOR A WHILE.

THE CONVECTION FROM LAST EVENING HAS DIED OUT BUT IT REMAINS
UNSTABLE ENOUGH TO POP A FEW WEAK CELLS FROM TIME TO TIME. ONE
SUCH CELL IS MOVING THROUGH SOUTHERN JOSEPHINE COUNTY RIGHT NOW.
IT HASN'T PRODUCED ANY LIGHTNING, AND IT'S PRETTY COMPACT. BUT IT
IS FAIRLY TALL, TOPPING OUT AT AROUND 30 KFT. WOULDN'T BE
SURPRISED TO SEE ANOTHER CELL OR TWO LIKE THAT THIS MORNING.

HEIGHTS START LOWERING TODAY AS A TROUGH DROPPING THROUGH THE NE
PACIFIC APPROACHES. THE MODELS ARE ALL CONSISTENT IN SHOWING OUR
TEMPERATURES TO BE A TAD COOLER THAN YESTERDAY ON THE WEST SIDE,
BUT STILL WELL ABOVE NORMAL. ELSEWHERE, TEMPERATURES WILL BE
ROUGHLY THE SAME AS YESTERDAY. I'M NOT ENTIRELY SURE THAT OUR
FORECAST HIGH OF 101 IN MEDFORD IS HIGH ENOUGH. FREQUENTLY COOLER
AIR IS SLOWER TO ARRIVE THAN THE MODELS SHOW AND WE GET BURNED (NO
PUN INTENDED) ON OUR HIGHS THE DAY JUST PRIOR TO THE BIG COOL
DOWN. BUT YESTERDAY'S 106 WAS SO ANOMALOUS THAT I'LL KEEP WHAT WE
HAVE FOR TODAY.

THE OTHER CONCERN FOR TODAY IS THE THUNDERSTORM POTENTIAL. IT WILL
BE VERY UNSTABLE (LI'S < -2, MID LEVEL LAPSE RATES > 8, CAPES
200-500 J/KG) OVER THE SOUTHEASTERN PORTION OF THE FORECAST AREA -
ROUGHLY SOUTHEAST OF A LINE FROM AROUND MT. SHASTA TO LAKEVIEW. IN
FACT, THE NAM DEPICTS SOMETHING THAT LOOKS MUCH LIKE A FRONT LATE
THIS AFTERNOON AND EARLY EVENING DEVELOPING IN THAT AREA AND THEN
MOVING EAST. IT LINES UP CONVECTION ALONG THAT BOUNDARY AND HAS
RATHER BREEZY WINDS BEHIND IT. I'M NOT JUMPING ON THE NAM
BANDWAGON ALL THE WAY SINCE IT HAS BEEN FLAKY LATELY.
NEVERTHELESS, ALL INDICATORS ARE THAT THE BEST CHANCE FOR THUNDER
WILL BE OVER THE AFOREMENTIONED AREAS. I'VE KEPT THUNDERSTORM
PROBS IN THE SLIGHT CHANCE CATEGORY, BUT THIS WILL HAVE TO BE
WATCHED AS I COULD SEE HOW WE GET MORE THAN THAT.

THE TROUGH BEGINS MOVING ONSHORE SATURDAY AND WE'LL FINALLY BREAK
THIS HEAT WAVE. THERE REMAINS A SLIGHT CHANCE OF CONVECTION ALONG
OUR SOUTHERN TIER OF COUNTIES BUT IT IS REMOTE. TEMPERATURES COOL
5-10 DEGREES AREA-WIDE SATURDAY. SUNDAY LOOKS DRY DESPITE THE
TROUGH AXIS MOVING RIGHT OVER US. THIS WILL KNOCK ANOTHER 5
DEGREES OR SO OFF OUR TEMPERATURES. BOTH SATURDAY AND SUNDAY
AFTERNOONS WILL BE RATHER DRY AND BREEZY, WHICH COULD PRESENT A
FIRE WEATHER CONCERN IF TODAY'S (OR PREVIOUS DAY'S) LIGHTNING HAS
RESULTED IN ANY STARTS.

NO CHANGES WERE MADE TO THE EXTENDED FORECAST AS ALL THINGS
CONTINUE TO POINT TO DRY WEATHER WITH TEMPERATURES AROUND NORMAL
THROUGH NEXT WEEK. -WRIGHT

AVIATION...BASED ON THE 26/06Z TAF CYCLE.

MARINE STRATUS WITH AREAS OF IFR CIGS IS EXPECTED TO CONTINUE ALONG
THE COAST AND INTO COASTAL VALLEYS NORTH OF CAPE BLANCO THROUGH
EARLY THIS MORNING. SOME IFR FOG IS ALSO EXPECTED. SOUTH OF CAPE
BLANCO...OFFSHORE FLOW SHOULD KEEP SKIES MOSTLY CLEAR...BUT PATCHY
VALLEY FOG MAY DEVELOP TOWARD SUNRISE. MARINE STRATUS AND FOG IS
EXPECTED TO CLEAR TO VFR BETWEEN 16-18Z. INLAND...VFR IS EXPECTED
OVER THE NEXT 24 HOURS. ISOLATED THUNDERSTORMS ARE EXPECTED TO
DEVELOP FRIDAY AFTERNOON AND EVENING OVER AREAS EAST OF THE CASCADES
IN SOUTHERN OREGON AND INTO NORTHERN CALIFORNIA. GUSTY AND VARIABLE
WINDS WILL ACCOMPANY THUNDERSTORMS. CC

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM NOON TODAY TO 8 PM PDT SATURDAY FOR
     ORZ031.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM
     PDT SATURDAY FOR PZZ356.
     HAZARDOUS SEAS WARNING FROM 11 AM THIS MORNING TO 11 PM PDT
     SUNDAY FOR PZZ356.
     GALE WARNING FROM 11 AM SATURDAY TO 11 PM PDT SUNDAY FOR PZZ356.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
     MORNING FOR PZZ356.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT SUNDAY FOR
     PZZ350-370.
     HAZARDOUS SEAS WARNING FROM 11 AM THIS MORNING TO 5 AM PDT
     SUNDAY FOR PZZ370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
     MORNING FOR PZZ370.
     GALE WARNING UNTIL 11 PM PDT SUNDAY FOR PZZ376.
     HAZARDOUS SEAS WARNING UNTIL 11 AM PDT MONDAY FOR PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
     FOR PZZ350.