000
FXUS66 KMFR 190358
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
858 PM PDT TUE JUN 18 2013
.DISCUSSION...AN UPPER LOW IS LOCATED JUST OFF THE OREGON COAST
AND WILL MOVE INLAND LATE TONIGHT INTO WEDNESDAY. SHOWERS AND A
FEW THUNDERSTORMS HAVE DEVELOPED INLAND OVER THE AREA. ISOLATED
THUNDERSTORMS HAVE MAINLY BEEN LIMITED TO THE CASCADES EAST THIS
EVENING. EXPECT THUNDERSTORM ACTIVITY TO DIMINISH WISH SUNSET.
SHOWER ACTIVITY EAST OF THE CASCADES WILL CONTINUE THROUGH THE
EVENING AND INTO THE NIGHT AS AN UPPER JET SHIFTS EAST OVER THE
AREA. THEN EAST SIDE LOCATIONS MAY SEE A BRIEF BREAK IN SHOWER
ACTIVITY LATE TONIGHT BEFORE THE LOW MOVES INLAND BRINGING MORE
SHOWERS WEDNESDAY. WEST OF THE CASCADES EXPECT INCREASING SHOWERS
TONIGHT AS THE UPPER LOW PUSHES INTO THE COAST. AN AREA OF
MOISTURE AND SHOWERS IS VISIBLE ON SATELLITE 50 TO 100 MILES
OFFSHORE. THESE SHOWERS ARE EXPECTED TO MOVE INLAND LATE THIS
EVENING INTO TONIGHT AND WILL LIKELY BRING WIDESPREAD SHOWERS TO
WEST SIDE LOCATIONS WITH SHOWERS SPILLING OVER EAST OF THE
CASCADES BY MID MORNING WEDNESDAY. ACROSS NORTHERN CALIFORNIA
SHOWER ACTIVITY IS LIKELY TO REMAIN SCATTERED TONIGHT AND
WEDNESDAY.
WINDS ARE EXPECTED TO DECREASE ON WEDNESDAY COMPARED TO TODAY.
ALTHOUGH LIGHTER...SOME BREEZY CONDITIONS ARE STILL POSSIBLE
MAINLY FOR LOCATIONS EAST OF THE CASCADES.
AS THIS LOW MOVES INLAND AND EAST OF THE AREA...EXPECT DIMINISHING
SHOWERS BY WEDNESDAY EVENING AND NIGHT.
UPDATED THE EVENING FORECAST TO INCREASE SHOWERS TO WIDESPREAD
FOR AREAS FROM THE CASCADES EAST AND DECREASE COVERAGE WEST OF THE
CASCADES.
&&
.AVIATION...THROUGH WEDNESDAY EVENING, ONSHORE FLOW WITH A LOW MOVING
EAST-SOUTHEAST INTO OREGON WILL CONTINUE MVFR CEILINGS WITH NUMEROUS
SHOWERS AT THE COAST...EXCEPT AREAS OF IFR AT THE CURRY COUNTY
COAST.
THERE WILL ALSO BE AREAS OF MVFR CIGS WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS INLAND. THUNDERSTORMS WILL BE MAINLY
DURING THE AFTERNOON AND EVENING HOURS. THESE SHOWERS AND MVFR CIGS
WILL OCCASIONALLY OBSCURE TERRAIN. ALSO, EAST OF THE
CASCADES...GUSTY WEST TO NORTHWEST WINDS WILL DIMINISH AFTER 06Z
THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 250 PM PDT TUE JUN 18 2013/
SHORT TERM...THE UPPER LEVEL LOW PRESSURE OFF NW OREGON COAST
WILL CONTINUE TO SPEND A SERIES OF WEAK DISTURBANCE INLAND TONIGHT
AND WEDNESDAY. COOL AND UNSTABLE AIR MASS WILL HELP TO
DESTABILIZE THE ATMOSPHERE WITH INTERMITTENT LIGHT RAIN SHOWERS.
THUNDERSTORMS ARE POSSIBLE THIS EVENING..MAINLY FROM THE CASCADES
EAST AND SOUTH INTO SISKIYOU AND MODOC COUNTIES. INSTABILITY
INDICES ARE NOT VERY HIGH AND LIGHTNING STRIKES ARE EXPECTED TO BE
ISOLATED IN COVERAGE. EXPECT COOLER THAN NORMAL TEMPERATURES ON
WEDNESDAY AS MORE COOLER AIR MOVES INTO THE AREA ALONG WITH
POTENTIAL FOR SHOWERS. ONLY NORTHERN KLAMATH AND LAKE COUNTIES
WILL HAVE ENOUGH INSTABILITY FOR LIGHTNING STRIKES. SOME CLEARING
ON WEDNESDAY NIGHT COULD BRING TEMPERATURES IN THE KLAMATH AND
TULELAKE BASINS DOWN CLOSE TO FROST POINTS.
THE LOW PRESSURE IS EXPECTED TO MOVE INTO NE OREGON AND EASTERN
WASHINGTON ON THURSDAY BUT LINGERS IN THAT GENERAL AREA THROUGH
FRIDAY. WE WILL SEE SOME WARMING AND DRYING THURSDAY AND FRIDAY
THE COLD AIR MOVES EAST. HOWEVER THERE IS A CONCERN THAT MOISTURE
ROTATING AROUND THE LOW PRESSURE COULD LEAD TO UPSLOPE SHOWERS IN
THE FAR EASTERN DOUGLAS COUNTY AND NORTHERN KLAMATH AND LAKE
COUNTIES THROUGH FRIDAY WHEREAS THE CHANCE FOR THE REST OF OUR
FORECAST AREA SHOULD BE OVER.
LONG TERM...EXPECT BRIEF RIDGING ON SATURDAY WITH HIGHS WARMING
TO NORMAL...POSSIBLY INTO SUNDAY. WHILE BOTH LONG RANGE MODELS
HINT THAT ANOTHER LOW PRESSURE MOVE INLAND...THEY ARE BEGINNING TO
DIVERGE A BIT FROM SUNDAY INTO EARLY NEXT WEEK. THE ECMWF IS MORE
AGGRESSIVE WITH A FULL FLEDGED COLD FRONT INLAND WHEREAS THE GFS
HAS A WEAKER TROUGH MOVING THROUGH. THIS WILL AFFECT FORECAST
HIGHS NEXT WEEK. DECIDED TO STAY CLOSER TO THE GFS ON TEMPERATURES
KEEPING HIGHS CLOSE TO BUT JUST BELOW SEASONAL NORMS FROM SUNDAY
INTO NEXT WEEK. ALSO INTRODUCED PRECIPITATION TO THE EXTENDED
FORECAST. /FB
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
CC
