Gale Watch 13, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
255 PM PDT MON JUN 8 2015

.DISCUSSION...CURRENT VISIBLE IMAGE SHOWS CU BUILDING UP OVER THE
CASCADES...SISKIYOUS...NORTHERN CAL AND EAST OF THE CASCADES. MODELS
SHOW INSTABILITY IN THESE AREAS INTO THIS EVENING, BUT THE TRIGGER
IS WEAK. DESPITE THIS DESPITE THIS A FEW ISOLATED THUNDERSTORMS
COULD STILL POP UP IN NORTHERN CAL AND SOUTHERN CASCADES LATE THIS
AFTERNOON AS 700MB WINDS WILL BE LIGHT FROM THE SOUTH AND STRONG
SURFACE HEATING COULD OVERWHELM THE CAP. THE FOCUS FOR ISOLATED
STORMS WILL BE PRIMARILY OVER SISKIYOU COUNTY...ALONG AND EAST OF
THE CASCADES....EDGING UP INTO THE KALMIOPSIS.

THE MAIN FOCUS OF CONCERN IS TONIGHT THROUGH TUESDAY. THE MODELS
REMAIN CONTINUE TO SHOW A WEAK UPPER LOW OFF THE CALIFORNIA COAST
WITH A SOUTHEAST FLOW AND THIS WILL TAP INTO SOME OF THE TROPICAL
MOISTURE TONIGHT THROUGH TUESDAY. PW VALUES HAVE ALREADY INCREASED
WITH THIS MORNINGS SOUNDING SHOWING PWATS OVER AN INCH AND THE
MODELS INDICATE THEY WILL RANGE BETWEEN 1.00 AND 1.50 INCHES
TONIGHT. FOR TONIGHT, WE'LL HAVE ISOLATED TO SCATTERED SHOWERS, BUT
ENOUGH INSTABILITY EXIST TO WARRANT A THREAT FOR ISOLATED
THUNDERSTORMS.

TUESDAY WILL BE THE MOST ACTIVE DAY OF THE WEEK WITH SCATTERED TO
NUMEROUS THUNDERSTORMS, ESPECIALLY TUESDAY AFTERNOON AND EARLY
EVENING. TWO MAIN CONCERNS EXIST ON TUESDAY. ONE IS THE POTENTIAL
FOR NEW STARTS FROM LIGHTNING. SECOND IS THE POTENTIAL FOR FLASH
FLOODING OVER THE BURN SCARS FROM PREVIOUS FIRES. BOTH OF THESE WILL
NEED TO BE MONITORED CLOSELY. THE ONLY AREAS THAT WILL NOT BE UNDER
THE THREAT OF THUNDERSTORMS IS THE COAST AND UMPQUA BASIN...WHERE
THE MARINE LAYER WILL MAKE FOR MORE STABLE CONDITIONS. STORM MOTION
WILL BE SLOW...SO AREAS THAT GET PRECIPITATION MAY GET A LOT OF IT,
THUS THE CONCERN FOR FLASH FLOODING FOR THE BURN SCAR AREAS.

THE UPPER LOW WILL MOVE INLAND INTO THE BAY AREA WEDNESDAY AND DRIER
NORTHWEST FLOW ALOFT WILL START TO MOVE INTO THE AREA FROM THE
NORTHWEST AND PUSH THE THREAT FOR THUNDERSTORMS SOUTHEAST INTO
NORTHERN CAL AND EAST OF THE CASCADES. THE MODELS SUGGEST THE
HIGHEST MOISTURE CONTENT SHOULD BE CONFINED TO MODOC COUNTY. SO THEY
HAVE THE BEST CHANCE OF GETTING DECENT RAINFALL FROM STORMS.
MEANWHILE IT WILL BE DRY WEST OF THE CASCADES DUE TO A COMBINATION
OF INCREASING MARINE LAYER AND DRYING AT MID LEVELS. TEMPERATURES ON
WEDNESDAY WILL CONTINUE TO COOL...AND MOST OF THE INLAND AREAS HIGH
TEMPERATURES WILL BE 5 TO 15 DEGREES BELOW TUESDAY'S HIGHS.

AFTER WEDNESDAY, THE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING DRY
WEATHER RETURNING THURSDAY AND LASTING INTO AT LEAST THE FIRST HALF
OF NEXT WEEKEND. A THERMAL TROUGH WILL DEVELOP ALONG THE OREGON
COAST THURSDAY NIGHT AND LASTING THROUGH SATURDAY. TEMPERATURES WILL
BE ABOVE NORMAL, BUT WERE NOT EXPECTING THE BUG WARM UP LIKE WE HAD
THE LAST FEW DAYS BECAUSE WE'LL WAVE A WEAK TROUGH SWING NORTH OF
THE AREA FRIDAY FOLLOWED BY A WEAK WEST TO NORTHWEST FLOW SATURDAY.
-PETRUCELLI

&&

.AVIATION...FOR THE 08/18Z TAF CYCLE...VFR IS PRESENT ACROSS ALL
AREAS AND WILL CONTINUE THROUGH EARLY THIS EVENING. THE MARINE LAYER
WILL SURGE BACK ALONG THE COAST AFTER 00Z AND PERSIST INTO TUESDAY
MORNING. FOR THE REMAINDER OF THE AREA, SKIES WILL REMAIN VFR FOR
THE NEXT 24 HOURS. THE MAIN CONCERN WILL BE ISOLATED THUNDERSTORMS
LATE THIS AFTERNOON INTO THIS EVENING FROM THE CASCADES AND SISKIYOU
MOUNTAINS SOUTHWARD AND EASTWARD ACROSS NORTHERN CALIFORNIA AND
SOUTH CENTRAL OREGON. -SCHAAF

&&

.MARINE...UPDATED 530 AM PDT, MONDAY, 8 JUNE 2015...

THE THERMAL TROUGH HAS PUSHED OFFSHORE FROM CURRY COUNTY THIS
MORNING WITH REDUCED WIND SPEEDS OVER A TRIANGULAR AREA COVERING THE
INNER WATERS FROM PORT ORFORD SOUTHWARD AND INTO THE EXTREME
SOUTHEAST PORTION OF THE OUTER WATERS TO ABOUT 30 NM FROM PT ST
GEORGE. ELSEWHERE, MODERATE TO STRONG NORTH WINDS WILL PERSIST WITH
THE COMBINATION OF WIND WAVES AND A FRESH SWELL PRODUCING MODERATE
TO HIGH SEAS ACROSS THE WATERS.

WIND SPEEDS AND SHORT PERIOD SEAS WILL RISE AGAIN TUESDAY WITH WINDS
EXPECTED TO BUILD TO THE HIGH END OF SMALL CRAFT ADVISORY CRITERIA
ONCE AGAIN. WINDS WILL BECOME STRONGEST IN THE WATERS SOUTH OF CAPE
BLANCO FROM 10 TO 40 NM FROM SHORE AND MAY LOCALLY REACH GALE FORCE
DURING THE AFTERNOON. MEANTIME, THERE WILL BE WEAK WINDS NEAR SHORE
SOUTH OF BROOKINGS.

THIS PATTERN IS LIKELY TO PERSIST THROUGH THE REST OF THE WEEK.
MODEL AGREEMENT IS ABOUT TYPICAL WITH THE NAM MAINTAINING HIGH END
SMALL CRAFT ADVISORY CONDITIONS WEDNESDAY INTO THURSDAY WHILE THE
GFS SUGGESTS BUILDING STRENGTH COULD PRODUCE A SMALL AREA OF LOW END
GALES IN THE SOUTHERN OUTER WATERS ON WEDNESDAY AND FURTHER
STRENGTHENING ON THURSDAY INTO FRIDAY. /DW

.FIRE WEATHER...UPDATED 200 PM PDT, MONDAY, 8 JUNE 2015...

THE INCOMING THUNDERSTORM THREAT FOR TUESDAY IS REMINISCENT OF ONE
WE EXPERIENCED IN EARLY JULY OF 2014, WHEN SOME AREAS RECEIVED OVER
AN INCH OF RAIN AND OTHERS HAD MULTIPLE FIRE STARTS. FIRE STARTS
FROM THAT EVENT WERE FOUND FOR AT LEAST A WEEK AFTER THE LIGHTNING
OCCURRENCE. THERE IS HIGH CONFIDENCE IN SIGNIFICANT THUNDERSTORM
ACTIVITY OVER SISKIYOU COUNTY AND FROM THE CASCADES AND SISKIYOUS
EASTWARD ON TUESDAY. THERE IS LESS CONFIDENCE IN HOW FAR NORTH AND
WEST THE STORMS WILL MAKE IT INTO SOUTHWESTERN OREGON TUESDAY. STORM
ACTIVITY COULD CONTINUE OVERNIGHT, BEFORE RE-INTENSIFYING WEDNESDAY
AFTERNOON AND EVENING. HOWEVER, THE FOCUS OF STORMS WILL GRADUALLY
SHIFT SOUTH AND EAST, AND BY WEDNESDAY AFTERNOON, CONVECTION SHOULD
BE RELEGATED MOSTLY TO NORTHERN CALIFORNIA AND SOUTHERN PORTIONS OF
THE EAST SIDE IN OREGON.

THERE IS ALSO THE POSSIBILITY OF LIGHTNING THIS AFTERNOON THROUGH
TUESDAY MORNING. COVERAGE WILL LIKELY NOT BE AS EXTENSIVE AS ON
TUESDAY. ISOLATED COVERAGE IS EXPECTED DURING THE AFTERNOON AND
EVENING MAINLY OVER THE MOUNTAINS FROM THE CASCADES AND SISKIYOUS
SOUTHWARD AND EASTWARD THEN A FEW THUNDERSTORMS MAY CONTINUE
OVERNIGHT. THERE IS HIGH CONFIDENCE THAT STORMS WILL PRODUCE
SIGNIFICANT RAINFALL DUE TO HIGH PRECIPITABLE WATER VALUES AND SLOW
STORM MOTION, AND OLD BURN SCARS COULD SEE MOBILIZATION OF SEDIMENT
AND DEBRIS.

LOOKING INTO WEDNESDAY AND THURSDAY AFTERNOONS, FORECAST GUIDANCE
SUGGESTS THAT SOME AREA OF THE EAST SIDE, MAINLY NORTHERN LAKE
COUNTY, MAY APPROACH RED FLAG CRITERIA IN THE FORM OF GUSTY WINDS
AND LOW HUMIDITY. WILL NEED TO KEEP AN EYE ON THIS, ESPECIALLY IF
NEW STARTS RESULT FROM THE ACTIVE THUNDERSTORMS EARLIER IN THE
WEEK. -BPN/BTL/DW

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...
CA...
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT WEDNESDAY FOR
     PZZ350-356-370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT WEDNESDAY
     FOR PZZ350-356.
     HAZARDOUS SEAS WATCH FROM TUESDAY MORNING THROUGH LATE TUESDAY
     NIGHT FOR PZZ370.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT TUESDAY
     FOR PZZ370.
     GALE WATCH FROM TUESDAY MORNING THROUGH LATE TUESDAY NIGHT FOR
     PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT TUESDAY FOR
     PZZ376.
     HAZARDOUS SEAS WARNING UNTIL 5 AM PDT WEDNESDAY FOR PZZ376.