000
FXUS66 KMFR 171542
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
842 AM PDT MON JUN 17 2013

.DISCUSSION...UPDATES WERE ALREADY MADE THIS MORNING TO UPGRADE
THE FIRE WEATHER WATCH FOR MODOC TO A RED FLAG WARNING AND TO ADJUST
SKY GRIDS TO REALITY. THE BIG, CLOSED LOW HAS EDGED CLOSER TO US
THIS MORNING AND IS NOW CENTERED NEAR 45N/133W. A WEAK FRONT IS
APPROACHING OUR WATERS THIS MORNING AND WILL SLOWLY MAKE ITS WAY
TO THE COAST BY THIS EVENING...INCREASING THE THREAT FOR SHOWERS
OVER THESE AREAS. SKIES ARE CRYSTAL CLEAR ELSEWHERE INLAND FROM
THE COAST THIS MORNING. PER THIS MORNING`S SOUNDING AT KMFR, THERE
HAS BEEN SOME SLIGHT WARMING ALOFT WHICH HAS REDUCED INSTABILITY.
WE HAVE MOISTENED SOMEWHAT, AND SURFACE-BASED INSTABILITY WILL
PRODUCE CUMULUS AGAIN THIS AFTERNOON. HOWEVER, WE WILL REMAIN
CAPPED AT AROUND 700 MB EXCEPT OVER NORTHERN LAKE AND KLAMATH
COUNTIES WHERE CONVECTION MAY BE ABLE TO PUNCH THROUGH THE
COMPARATIVELY WEAKER CAP. THIS LOOKS LIKE A REPEAT OF YESTERDAY`S
CONDITIONS. WE WILL SEE GUSTY SOUTHWEST WINDS ACROSS THE EAST SIDE
TODAY AND WHEN COMBINED WITH LOW HUMIDITIES, FIRE DANGER WILL BE
ELEVATED, ESPECIALLY ACROSS THE MODOC WHERE THEY ALSO HAVE DRY
FUELS AND HIGH AMBIENT FIRE DANGER. TODAY`S FOCUS WILL BE ON
TRYING TO NAIL DOWN THE SPECIFICS ON OUR CHANGE TO MUCH COOLER,
SHOWERY WEATHER AS THE UPPER LOW COMES ASHORE TOMORROW AND
WEDNESDAY. -WRIGHT

&&

.AVIATION...A FRONT WILL PUSH TOWARDS THE COAST TODAY AND INLAND
TOMORROW. ALONG THE COAST IFR CIGS WITH AREAS OF IFR VISIBILITIES
IN FOG ARE PRESENT THIS MORNING. CONDITIONS ARE EXPECTED TO
IMPROVE TO VFR WITH AREAS OF MVFR CIGS BY LATE THIS MORNING. THEN
EXPECT SHOWERS AND WIDESPREAD MVFR CIGS TO DEVELOP IN THE LATE
AFTERNOON AROUND 22-23Z BECOMING A MIX OF IFR AND MVFR CIGS AFTER
06Z. TONIGHT. ACROSS INLAND AREAS...VFR CONDITIONS ARE EXPECTED
THROUGH THIS AFTERNOON. THE APPROACHING FRONTAL SYSTEM WILL RESULT
IN INCREASING CLOUDS FROM WEST TO EAST TODAY...AND SHOWERY
PRECIPITATION IS EXPECTED TO IMPACT THE COAST AND AREAS FROM THE
CASCADES WEST THIS AFTERNOON AND EVENING WITH SHOWERS INCREASING
IN COVERAGE TONIGHT. ALSO ISOLATED THUNDERSTORMS ARE POSSIBLE EAST
OF THE CASCADES THIS AFTERNOON. ADDITIONALLY GUSTY WINDS WILL ALSO
BE A CONCERN AHEAD OF THE FRONT THIS AFTERNOON AND EVENING
ESPECIALLY EAST OF THE CASCADES...AND SOME MOUNTAIN WAVE
TURBULENCE COULD RESULT. TONIGHT EXPECT MVFR CIGS TO DEVELOP
INLAND ALONG COASTAL VALLEYS AND THROUGH THE UMPQUA BASIN WITH
AREAS OF MOUNTAIN OBSCURATIONS EXPECTED MAINLY FROM THE CASCADES
WEST. CC

&&

.PREV DISCUSSION... /ISSUED 402 AM PDT MON JUN 17 2013/

DISCUSSION...A LARGE AND SLOW-MOVING AREA OF LOW PRESSURE IS
CENTERED OFFSHORE AROUND 44N 135W. THE LOW IS EXPECTED TO NUDGE
EASTWARD TO AROUND 130W BY THIS EVENING AND USHER IN A PERIOD OF
COOLER AND WETTER CONDITIONS TONIGHT THROUGH WEDNESDAY NIGHT.
MUCH OF OUR AREA HAS NOT HAD MEASUREABLE RAINFALL YET THIS MONTH.
THAT WILL CHANGE FOR PARTS OF, BUT LIKLEY NOT ALL OF THE AREA WITH
A SERIES OF DISTURBANCES BRINGING PERIODS OF SHOWERS. THE
PROBABILITY STILL LOOKS HIGHEST WEST AND NORTH OF THE ROGUE VALLEY.

THE VERTICAL TEMPERATURE PROFILE TODAY WILL RESEMBLE THAT OF SUNDAY
WITH A REGION OF INSTABILITY THIS AFTERNOON AND EVENING FOCUSED
ON NORTHEAST OREGON BUT EXTENDING SOUTHWESTWARD INTO NORTHERN
PORTIONS OF KLAMATH AND LAKE COUNTIES. TEMPERATURES WILL TREND
ANOTHER FEW DEGREES COOLER TODAY AND GUSTY AFTERNOON AND EVENING
SOUTHWEST WINDS WILL BE GENERALLY A FEW MPH STRONGER THAN
YESTERDAY. THIS HAS LED TO A FIRE WEATHER WATCH FOR NORTHEAST
CALIFORNIA FOR STRONG WINDS AND LOW HUMIDITIES. THE FIRST SHOWERS
SHOULD DEVELOP THIS AFTERNOON BUT ACTIVITY IS EXPECTED TO TICK
UPWARD LATE TONIGHT.

COOLING WILL BE MUCH MORE NOTICEABLE ON TUESDAY AND THE
PROBABILITY OF SHOWERS AND THUNDERSTORMS WILL BE HIGHER AS THE
UPPER LOW MOVES INSIDE OF 130W. THE 03Z SREF MODEL HAS A SLIGHT
CHANCE OF THUNDERSTORMS LIMITED TO LAKE COUNTY ON TUESDAY. BUT I
HAVE MAINTAINED THE FORECAST OF A SLIGHT CHANCE OF THUNDERSTORMS
FOR A MUCH LARGER PORTION OF OUR AREA...EAST OF THE COASTAL RANGE.
THIS IS IN LINE WITH THE 00Z GFS AND WITH CONSIDERATION OF THE
INCREASE IN MOISTURE AND COOLING ALOFT.

THE UPPER LOW IS EXPECTED TO MOVE INLAND LATE TUESDAY NIGHT INTO
WEDNESDAY MORNING WITH AN ASSOCIATED SURFACE TROUGH WHICH WILL
BRING THE HIGHEST PROBABILITY OF SHOWERS. THE GFS AND ECMWF BOTH
STILL FOCUS MOST OF THE QPF ON THE COAST AND DOUGLAS COUNTY.

ONSHORE FLOW WILL PERSIST WEDNESDAY NIGHT WITH A DEEP MARINE LAYER
POSSIBLY PRODUCING SOME DRIZZLY SHOWERS AT THE COAST NORTH OF CAPE
BLANCO. FURTHER INLAND...CLOUD COVER WILL DIMINISH OVERNIGHT WITH
THE POSSIBILITY OF FREEZING TEMPERATURES ON THE EAST SIDE.

RIDGING WILL BRING A WARMING AND DRYING TREND THURSDAY INTO SATURDAY
..POSSIBLY CONTINUING INTO SUNDAY. ANOTHER LARGE UPPER
LOW IS EXPECTED TO APPROACH FROM THE WEST EARLY NEXT WEEK. I HAVE
GONE WITH A MODEL BLEND...INTRODUCING A SLIGHT CHANCE OF COASTAL
SHOWERS BY SUNDAY NIGHT. THE ECMWF SOLUTION IS FASTER AND
STRONGER THAN THE GFS...DEPICTING RAIN AT OUR COAST BEFORE THE
END OF SUNDAY NIGHT AND CONTINUING ON MONDAY.

&&

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

CA...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING FOR CAZ084-085.

PACIFIC COASTAL WATERS...NONE.

$$