Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 031602
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
902 AM PDT FRI JUL 3 2015

.SHORT TERM...MOISTURE AND SHORTWAVE ENERGY MOVING UP FROM THE
SOUTH WILL BRING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS
OVER SOUTHERN PORTIONS OF THE AREA TODAY AND SATURDAY WITH
INCREASING CHANCES ACROSS MUCH OF THE AREA SUNDAY INTO EARLY NEXT
WEEK.

THIS MORNING, SATELLITE AND RADAR IMAGERY SHOWS A BAND OF SHOWERS
AND CLOUDS JUST SOUTH OF THE AREA. THIS BAND IS EXPECTED TO MOVE UP
INTO MODOC AND SISKIYOU COUNTY THIS MORNING AND THIS AFTERNOON.
THIS IS EXPECTED TO BRING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE BEST CHANCE FOR THUNDERSTORMS IS IN SOUTHERN
SISKIYOU COUNTY AS WELL AS MODOC COUNTY. ISOLATED SHOWERS AND
THUNDERSTORMS ARE ALSO EXPECTED TO SPREAD INTO THE SISKIYOUS AND
POSSIBLY INTO PORTIONS OF THE SOUTHERN OREGON CASCADES AS WELL AS
EAST OF THE CASCADES INTO KLAMATH AND LAKE COUNTIES. THE GFS HAS
BEEN SHOWING SHOWERS CONTINUING OVERNIGHT INTO SATURDAY MORNING AS
THE BAND OF MOISTURE GRADUALLY LIFTS NORTH OVER THE AREA WITH
CHANCES FOR SHOWERS FROM NORTHERN CALIFORNIA INTO SOUTHWEST
OREGON. HOWEVER, THE OTHER MODELS HAVE CONTINUED TO INDICATE
MAINLY DRY CONDITIONS EXPECT FOR SHOW LINGERING SHOWERS POSSIBLE
IN NORTHERN CALIFORNIA TONIGHT. HAVE LEANED TOWARDS THE DRIER
OVERNIGHT SOLUTION BUT THINK THERE WILL BE CLOUD COVER MOVING OVER
THE AREA TONIGHT AND LIFTING NORTH SATURDAY MORNING. STRONGER
SHOWERS AND THUNDERSTORMS TODAY MAY BRING SIGNIFICANT RAIN DUE TO
THE SLOW MOVEMENT OF THESE STORMS.

SATURDAY AFTERNOON, MODELS ARE INDICATING ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS WILL BEGIN AS MOISTURE AND SHORTWAVES MOVE INTO
THE AREA FROM THE SOUTH. THESE STORMS INITIALLY ARE EXPECTED TO
AFFECT NORTHERN CALIFORNIA AND LIKELY WILL BE ISOLATED IN COVERAGE BUT
IN THE LATE AFTERNOON AND EVENING, STORM COVERAGE MAY INCREASE
WITH SCATTERED THUNDERSTORMS POSSIBLE OVER MODOC AND PORTIONS OF
SISKIYOU COUNTY WITH SHOWERS AND THUNDERSTORMS ALSO SPREADING
NORTHWARD INTO SOUTHERN KLAMATH AND LAKE COUNTIES. MODELS
INDICATE SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE OVERNIGHT
IN NORTHERN CALIFORNIA SATURDAY NIGHT INTO SUNDAY AS SHORTWAVES
MOVE INTO THE AREA. THEN CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASE ACROSS SOUTHWEST OREGON AND NORTHERN CALIFORNIA SUNDAY
AFTERNOON AND EVENING.

&&

.AVIATION...FOR THE 03/12Z TAF CYCLE...ALONG THE COAST...IFR TO LIFR
CEILINGS AND VISIBILITIES IN AREAS NORTH OF CAPE BLANCO AND ALSO THE
SOUTH COAST NEAR BROOKINGS SHOULD IMPROVE TO VFR BY LATE MORNING.
OVER THE REMAINDER OF THE AREA...VFR CONDITIONS WILL PREVAIL...BUT
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE OVER THE
OREGON CASCADES SOUTH OF CRATER LAKE...OVER SOUTHERN KLAMATH AND
LAKE COUNTIES...AND OVER SISKIYOU AND MODOC COUNTIES. SVEN

&&

.MARINE...UPDATED 800 AM PDT FRIDAY 3 JULY 2015...A THERMAL TROUGH
WILL PERSIST NEAR THE COAST INTO SATURDAY. SMALL CRAFT ADVISORY
NORTH WINDS AND STEEP SEAS WILL PREVAIL DURING THIS TIME FRAME.
WINDS AND WAVES WILL GRADUALLY SUBSIDE THIS WEEKEND...WITH STRATUS
AND FOG IN MOST OF THE COASTAL WATERS THROUGH THE WEEKEND. -SVEN/BPN


&&

.PREV DISCUSSION... /ISSUED 349 AM PDT FRI JUL 3 2015/

DISCUSSION...CURRENT IR IMAGE SHOWS CLOUDS WITH ISOLATED SHOWERS
SOUTH OF THE FORECAST AREA AND THIS IS SLOWLY ADVANCING NORTHWARD
INTO NORTHERN CAL. THIS SHOULD BE ENOUGH TO LIMIT THE AMOUNT OF
DAYTIME HEATING AND THUS IT WILL NOT BE AS UNSTABLE IN THE
AFTERNOON. THEREFORE WE`LL KEEP A SLIGHT CHANCE OF THUNDERSTORMS
IN THE FORECAST MAINLY FOR NORTHERN CAL, BUT ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE FOR THE SOUTHERN CASCADES AND
SOUTHERN LAKE AND KLAMATH COUNTIES. HOWEVER THE MODELS SHOW A
SHORTWAVE MOVING NORTH INTO NORTHERN CAL LATE IN THE AFTERNOON. IF
THE CLOUDS BREAK UP ENOUGH AND THERE`S ENOUGH CLEARING, THEN WE
COULD SEE MORE THUNDERSTORM ACTIVITY. STORM MOTION WILL BE FROM
EAST TO WEST BETWEEN 10-15 KNOTS. EXPECT ISOLATED STORMS TO FORM
OVER THE HIGHER TERRAIN, THEN MOVE OFF THE HIGHER TERRAIN AND MOVE
WEST TO NORTHWEST.

SHORTWAVES WILL DRIFT OVER THE AREA SATURDAY AND SUNDAY. THE MID
LEVEL MOISTURE WILL BE LACKING ON SATURDAY, EXCEPT FOR SOUTHEAST
MODOC COUNTY. HOWEVER...THERE COULD BE A STRONGER TRIGGER IN
NORTHERN CAL AND COULD RESULT IN SCATTERED THUNDERSTORMS LATE IN
THE AFTERNOON AND EVENING FOR PORTIONS OF NORTHERN CAL AND
SOUTHEAST LAKE COUNTY.

ON SUNDAY...THE BEST CHANCE FOR STORMS WILL BE MAINLY ALONG AND
EAST OF THE CASCADES AND NORTHERN CAL. THE STEERING WINDS SUNDAY
WILL BE FROM THE SOUTHWEST AROUND 10 KTS, SO THEY WILL BE LOW
MOVERS AND WILL TEND TO DRIFT EAST TO NORTHEAST.

TEMPERATURES WILL REMAIN HOT THROUGH THE WEEKEND AND WILL BE NEAR
TRIPLE DIGITS FOR PARTS OF THE ROUGE...ILLINOIS AND SHASTA VALLEY
AND KLAMATH RIVER VALLEY.

GUIDANCE, OVERALL, HAS INCREASED THE THUNDERSTORMS THREAT OVER THE
AREA EARLY TO MID NEXT WEEK. THIS IS BECAUSE THE UPPER LEVEL LOW
OFF OF THE COAST PUSHES EASTWARD, PUTTING US IN A MORE FAVORABLE
POSITIONS FOR THUNDERSTORMS AND, POSSIBLY, SOME WITH WETTING
PRECIPITATION. WE EXPECT THAT THIS WILL ALSO BRING ABOUT A
WELCOME COOL DOWN ACROSS THE AREA. THE WEST SIDE DOES RUN THE
RISK OF THUNDERSTORMS NEXT, THOUGH THE GREATEST THREAT WILL
CONTINUE TO BE SOUTH OF THE SISKIYOUS AND FROM THE CASCADES
EASTWARD. -PETRUCELLI



&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORZ023.
     HEAT ADVISORY UNTIL 11 PM PDT SATURDAY FOR ORZ024-026.

CA...HEAT ADVISORY UNTIL 11 PM PDT SATURDAY FOR CAZ080-081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PDT SUNDAY
     FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 PM PDT SATURDAY FOR
     PZZ376.

$$

CC


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