000
FXUS66 KMFR 130907
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
207 AM PDT THU JUN 13 2013

.DISCUSSION...MODELS CONTINUE ON TRACK...BOTH RUN TO RUN AND MODEL
TO MODEL THROUGH THE WEEKEND. A COLD POOL WITH 500 MB TEMPS IN THE
-22 TO -25 C OVER THE NORTHERN CASCADES AND OVER TO THE NORTHERN
EAST SIDE COMBINES WITH WEAK MOISTURE TO BRING WEAK INSTABILITY TO
THAT SAME AREA THIS AFTERNOON AS THE COLD FRONT MOVES INTO THE
REGION BRINGING PRECIPITATION TO MOSTLY. HOWEVER...WITH DEW POINTS IN
THE LOWER 40S IN THAT AREA HAVE GONE WITH A SLIGHT CHANCE INSTEAD
OF ISOLATED AS AM THINKING ONLY OF A SLIGHT CHANCE OF A
THUNDERSTORM DEVELOPING RATHER THAN BASING ON COVERAGE.

A WEAK UPPER LEVEL RIDGE BUILDS IN QUICKLY BEHIND THE EXITING
SYSTEM FRIDAY BRINGING A RAPID WARM-UP. A DEEPENING UPPER LEVEL
LOW APPROACHES FROM OFFSHORE OF VANCOUVER ISLAND SATURDAY...AND
WITH LOW PRESSURE IN CENTRAL CALIFORNIA AND HIGH PRESSURE IN THE
GREAT BASIN SEMI-MONSOONAL MOISTURE BEGINS TO FEED INTO THE REGION
INLAND. SATURDAY CONTINUES TO LOOK TO BE A DAY OF PRIMING THE PUMP
FOR SUNDAY`S CONVECTION...BUT WITH COMPUTED FROM 850 LI`S AROUND
-1 AND 700-500 RH AROUND 60 PERCENT IN THE NORTHERN CASCADES
HAVING A CELL DEVELOP ENOUGH TO DROP SOME LIGHTNING BEFORE IT
MOVES NORTH OUT OF THE AREA IS DEFINITELY NOT OUT OF THE QUESTION.
AM SKEPTICAL OF THE GFS SOLUTION ON SUNDAY. THE ECMWF MAINTAINS
THE CLOSER TO SHORE SOLUTION OF THE UPPER LOW A LITTLE BEYOND 132
W WITH THE GFS NOW PUTTING THIS LOW AROUND 136 W. THIS SHOULD
CONTINUE TO INCREASE THE SOUTHERLY THETA E FEED INTO THE REGION
WITH MORE INSTABILITY WITH GREATER COVERAGE. WITH THIS IN MIND
WILL NOT CHANGE THE CONVECTIVE FORECAST FOR SUNDAY.


&&

.AVIATION...FROM THE  CASCADES WEST AND SISKIYOUS NORTH...VFR
CONDITIONS WILL PREVAIL INITIALLY BUT AREAS OF MVFR CIGS WILL
SPREAD FROM ALONG THE COAST AND UMPQUA BASIN...SPILLING INTO THE
ROGUE VALLEY...INTO THIS MORNING BEFORE CLEARING TO VFR
AGAIN. SCATTERED LIGHT SHOWERS WILL DEVELOP THIS MORNING...MOSTLY
OVER THE NORTH COAST AND UMPQUA BASIN. ELSEWHERE...VFR CONDITIONS
WILL PREVAIL THROUGH THURSDAY...BUT ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS ARE POSSIBLE NORTH AND EAST OF KLMT. /FB


&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT EARLY
     THIS MORNING FOR PZZ356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 PM THIS AFTERNOON
     TO 5 PM PDT FRIDAY FOR PZZ310-356-376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 5 PM THIS AFTERNOON TO 5 AM
     PDT SATURDAY FOR PZZ376.
     HAZARDOUS SEAS WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY
     EVENING FOR PZZ376.

$$

SVEN