000
FXUS66 KMFR 240930
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
230 AM PDT FRI MAY 24 2013
.DISCUSSION...THE UPPER LOW THAT HAS HOVERED NEAR THE FORECAST AREA
THE LAST FEW DAYS WILL FINALLY LIFT NORTHEAST INTO WASHINGTON STATE
AND WEAKEN. THIS WILL RESULT IN DECREASING SHOWERS FROM SOUTH TO
NORTH...MILDER TEMPERATURES AND DECREASING CLOUD COVER. IN FACT THE
AFTERNOON SHOULD TURN OUT PRETTY NICE WITH PARTLY CLOUDY SKIES AND
TEMPERATURES NEAR NORMAL IN THE ROGUE VALLEY. DRY WEATHER CONTINUES
TONIGHT WITH WEAK TROFING OVER THE AREA.
MODELS SHOW A STRONGER SHORTWAVE TROF MOVING SOUTH INTO WESTERN
OREGON SATURDAY MORNING AND WE`LL SEE SHOWERS STARTING TO DEVELOP
NORTH OF THE UMPQUA DIVIDE IN THE MORNING...THEN SHOWERS ARE
EXPECTED TO DEVELOP ELSEWHERE IN THE AFTERNOON AS THE UPPER TROF
SWINGS SOUTHEAST. MODELS SUGGEST THERE MAY BE ENOUGH INSTABILITY FOR
ISOLATED THUNDERSTORMS EAST OF THE CASCADES SATURDAY AFTERNOON AND
EVENING.
AN UPPER LOW MOVES INTO THE FORECAST AREA SUNDAY AND THIS IS
EXPECTED TO BRING MORE WIDESPREAD SHOWERS. THE EASTSIDE WILL HAVE A
SLIGHT CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON AND EVENING.
THE UPPER LOW LIFT NORTHEAST SUNDAY NIGHT AND ANY DRY BREAKS WILL BE
BRIEF. THE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING A STRONGER
FRONTAL BOUNDARY BRINGING THE POTENTIAL FOR STEADY RAIN TO THE COAST
MID TO LATE MONDAY MORNING...THEN SPREADING INLAND MONDAY AFTERNOON
SO IT SHOULD NOT BE A TOTAL WASH OUT -PETRUCELLI
&&
.AVIATION...
BASED ON THE 24/06Z TAF CYCLE.
DEEP MOISTURE CONTINUES TO STREAM IN ACROSS THE NORTH COAST INTO THE
NORTH CASCADES AROUND CRATER LAKE. THIS WILL LEAD TO AREAS OF RAIN
WITH MVFR CIGS AND MOUNTAIN OBSCURATIONS OVER NORTHERN
AREAS...ROUGHLY NORTH OF THE UMPQUA DIVIDE. WE MAY SEE A FEW SHOWERS
IN THE ROGUE VALLEY EARLY THIS MORNING WITH OCCASIONAL MVFR CIGS,
BUT MOST OF THE PRECIPITATION WILL REMAIN NORTH OF US. THE EAST
SIDE AND NORCAL WILL REMAIN VFR THROUGH TODAY WITH HIGH CLOUD OVER
ERN OREGON AND MOSTLY CLEAR SKIES IN NORCAL. -WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
11 AM PDT THIS MORNING FOR PZZ370-376.
$$
000
FXUS66 KMFR 240328
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
828 PM PDT THU MAY 23 2013
.DISCUSSION...NO UPDATES PLANNED THIS EVENING. A STEADY STREAM OF
MOISTURE REMAINS AIMED AT THE NORTH COAST AND UMPQUA AREAS THIS
EVENING. WHILE WEBCAMS GENERALLY SHOW DRY ROADS AND MANY AREA OBS
HAVEN`T RECORDED RAIN IN A WHILE, THERE IS ANOTHER PLUME OF DEEPER
MOISTURE MOVING SOUTH ALONG THE COAST, SO RAIN OUGHT TO START UP
OVER THESE AREAS THIS EVENING AND CONTINUE TONIGHT. THE REST OF
US ARE CURRENTLY DRY AND WILL LIKELY ONLY BE DODGING SCATTERED
SHOWERS TONIGHT. THE CURRENT FORECAST COVERS THIS WELL. -WRIGHT
&&
.AVIATION...LOW PRESSURE TO THE NORTH WILL CONTINUE TO BRING SOME
LIGHT RAIN ALONG WITH A MIX OF VFR AND MVFR NORTH OF THE UMPQUA
DIVIDE AND ALONG THE NORTH COAST THROUGH TONIGHT. MOSTLY VFR IS
EXPECTED SOUTH OF THE UMPQUA DIVIDE THROUGH TONIGHT, BUT CANNOT
RULE OUT SOME MVFR IN ISOLATED AREAS OVERNIGHT...THEN AGAIN TOWARD
SUNRISE OVER THE VALLEYS. PARTIAL MOUNTAIN OBSCURATION IS ALSO
LIKELY, ESPECIALLY ACROSS THE NORTHERN HALF OF THE CWA. EAST OF
THE CASCADES...SOME SCATTERED SHOWERS COULD RESULT IN BRIEF
PERIODS OF MVFR THROUGH TONIGHT. OTHERWISE...VFR WILL PREVAIL.
-BPN
&&
.PREV DISCUSSION... /ISSUED 235 PM PDT THU MAY 23 2013/
SHORT TERM...THE UPPER LOW REMAINS OVER THE REGION TODAY AND
TONIGHT. AS THE CENTER OF THE LOW SWINGS SOUTHWARD ALONG THE
COAST TODAY THEN INLAND THIS EVENING AND TONIGHT EXPECT ADDITIONAL
SHOWERS TO MOVE INTO THE AREA. ON FRIDAY THE LOW CENTER WILL SHIFT
NORTHEAST THEN A BROAD TROUGH REMAINS OVER THE REGION ON SATURDAY
AND SUNDAY. EMBEDDED WITH THE TROUGH...ANOTHER SHORTWAVE IS
FORECAST TO MOVE TOWARDS THE COAST SATURDAY AND INLAND SATURDAY
NIGHT AND SUNDAY. THIS WILL BRING ADDITIONAL SHOWERS SATURDAY WITH
INCREASING SHOWER ACTIVITY ON SUNDAY. ALSO DURING THE AFTERNOON
AND EVENING TODAY AND AGAIN ON SATURDAY AND SUNDAY THERE IS A
SLIGHT CHANCE FOR THUNDERSTORMS FOR LOCATION EAST OF THE CASCADES.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOP EAST OF
THE CASCADES THIS AFTERNOON WHILE FROM THE CASCADES WEST...SHOWERS
ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON INTO THIS EVENING AS
THE UPPER LOW CENTER MOVES INTO CENTRAL OREGON. THE BEST CHANCES
FOR SHOWER ACTIVITY WILL BE OVER COOS AND DOUGLAS COUNTIES AS WELL
AS INTO THE SOUTHERN OREGON CASCADES WITH ISOLATED TO SCATTERED
SHOWERS IN OTHER AREAS OF THE CWA. ALSO OF NOTE IS THAT ANOTHER
COOL NIGHT IS EXPECTED EAST OF THE CASCADES TONIGHT INTO EARLY
FRIDAY MORNING WITH LOW TEMPERATURES EXPECTED NEAR OR JUST ABOVE
FREEZING. IN THE KLAMATH BASIN...DO NOT EXPECT WIDESPREAD FREEZING
CONDITIONS TONIGHT AND AREAS THAT REACH FREEZING MAY JUST BRIEFLY
DIP INTO THE LOW 30S SO HAVE NOT ISSUED A FREEZE WARNING FOR THIS
AREA.
AS THE LOW CENTER TRACKS TO THE NORTHEAST ON FRIDAY EXPECT
DECREASING SHOWERS ACROSS THE AREA BY AFTERNOON. MODELS CONTINUE TO
INDICATE A BROAD TROUGH WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. THIS IS EXPECTED TO BRING MILD TEMPERATURES WITH HIGHS
NEAR OR JUST BELOW NORMAL. CHANCES FOR SHOWERS WILL CONTINUE AS
WELL ON THE WEEKEND. ANOTHER SHORTWAVE IS FORECAST TO MOVE TOWARDS
THE AREA SATURDAY THEN INLAND SUNDAY. AHEAD OF THE SHORTWAVE
EXPECT SOME SCATTERED SHOWERS TO DEVELOP SATURDAY AFTERNOON AND
EVENING. A SLIGHT CHANCE OF THUNDERSTORMS IS ALSO
POSSIBLE...MAINLY EAST OF THE CASCADES ON SATURDAY. BY SUNDAY
MODELS INDICATE CONTINUED MOISTURE AND INCREASING INSTABILITY.
EXPECT MOST AREAS TO SEE A CHANCE FOR SHOWERS SUNDAY WITH
THUNDERSTORMS POSSIBLE IN THE AFTERNOON AND EVENING FROM THE
CASCADES EAST.
LONG TERM...MEMORIAL DAY THROUGH THURSDAY...CONFIDENCE REMAINS HIGH
IN THE OVERALL WEATHER PATTERN IN THE EXTENDED AS GEFS/ECMWF
ENSEMBLE MEANS BOTH FOCUS A TROUGH OVER THE WESTERN UNITED STATES
WITH BELOW NORMAL HEIGHTS. WHILE IT WON`T BE AS COOL AS IT WAS
EARLIER THIS WEEK, TEMPERATURES OVERALL FOR THE PERIOD WILL LIKELY
REMAIN SLIGHTLY BELOW NORMAL. THAT TRANSLATES TO UPPER 60S AND LOWER
70S FOR HIGHS IN MEDFORD. TIMING AND STRENGTH DETAILS OF INDIVIDUAL
SHORT WAVES MOVING INTO THE NORTHWEST WILL BE DIFFICULT, BUT THE
STRONGEST IS LIKELY TO ARRIVE AT THE COAST MONDAY MORNING, THEN PUSH
INLAND DURING THE AFTERNOON/EVENING. THE 00Z DETERMINISTIC RUN OF
THE ECMWF WAS WEAKER AND FARTHER SOUTH WITH THIS FEATURE, BUT THE
12Z RUN HAS COME MORE IN LINE WITH THE 12Z GFS (THOUGH STILL IS A
BIT WEAKER AND FARTHER SOUTH). EVEN SO, FELT CONFIDENT ENOUGH HERE
TO INCREASE POPS DURING THIS TIME, SINCE THAT IS WHERE THE FOCUS OF
PRECIP LIKELY WILL BE. HEIGHTS WILL RISE A BIT TUESDAY, BUT REMAIN
BELOW NORMAL, SO HAVE MAINTAINED SLIGHT CHC TO CHC POPS. MODELS
SHOWING ANOTHER SHORT WAVE APPROACHING THE COAST WEDNESDAY INTO
THURSDAY IN THE MOIST WESTERLY ONSHORE FLOW. THIS SHOULD KEEP THE
PROBABILITY OF SHOWERS HIGHEST ALONG AND WEST OF THE CASCADES.
BEYOND THAT, THE GFS ENSEMBLES CARVE ANOTHER DEEP TROUGH/CLOSED LOW
OVER THE AREA/JUST OFFSHORE NEXT WEEKEND, WHILE THE ECMWF IS FLATTER
AND MORE ZONAL. SPILDE
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
5 AM PDT FRIDAY FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PDT FRIDAY
FOR PZZ350.
$$
000
FXUS66 KMFR 232135
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
235 PM PDT THU MAY 23 2013
.SHORT TERM...THE UPPER LOW REMAINS OVER THE REGION TODAY AND
TONIGHT. AS THE CENTER OF THE LOW SWINGS SOUTHWARD ALONG THE
COAST TODAY THEN INLAND THIS EVENING AND TONIGHT EXPECT ADDITIONAL
SHOWERS TO MOVE INTO THE AREA. ON FRIDAY THE LOW CENTER WILL SHIFT
NORTHEAST THEN A BROAD TROUGH REMAINS OVER THE REGION ON SATURDAY
AND SUNDAY. EMBEDDED WITH THE TROUGH...ANOTHER SHORTWAVE IS
FORECAST TO MOVE TOWARDS THE COAST SATURDAY AND INLAND SATURDAY
NIGHT AND SUNDAY. THIS WILL BRING ADDITIONAL SHOWERS SATURDAY WITH
INCREASING SHOWER ACTIVITY ON SUNDAY. ALSO DURING THE AFTERNOON
AND EVENING TODAY AND AGAIN ON SATURDAY AND SUNDAY THERE IS A
SLIGHT CHANCE FOR THUNDERSTORMS FOR LOCATION EAST OF THE CASCADES.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOP EAST OF
THE CASCADES THIS AFTERNOON WHILE FROM THE CASCADES WEST...SHOWERS
ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON INTO THIS EVENING AS
THE UPPER LOW CENTER MOVES INTO CENTRAL OREGON. THE BEST CHANCES
FOR SHOWER ACTIVITY WILL BE OVER COOS AND DOUGLAS COUNTIES AS WELL
AS INTO THE SOUTHERN OREGON CASCADES WITH ISOLATED TO SCATTERED
SHOWERS IN OTHER AREAS OF THE CWA. ALSO OF NOTE IS THAT ANOTHER
COOL NIGHT IS EXPECTED EAST OF THE CASCADES TONIGHT INTO EARLY
FRIDAY MORNING WITH LOW TEMPERATURES EXPECTED NEAR OR JUST ABOVE
FREEZING. IN THE KLAMATH BASIN...DO NOT EXPECT WIDESPREAD FREEZING
CONDITIONS TONIGHT AND AREAS THAT REACH FREEZING MAY JUST BRIEFLY
DIP INTO THE LOW 30S SO HAVE NOT ISSUED A FREEZE WARNING FOR THIS
AREA.
AS THE LOW CENTER TRACKS TO THE NORTHEAST ON FRIDAY EXPECT
DECREASING SHOWERS ACROSS THE AREA BY AFTERNOON. MODELS CONTINUE TO
INDICATE A BROAD TROUGH WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. THIS IS EXPECTED TO BRING MILD TEMPERATURES WITH HIGHS
NEAR OR JUST BELOW NORMAL. CHANCES FOR SHOWERS WILL CONTINUE AS
WELL ON THE WEEKEND. ANOTHER SHORTWAVE IS FORECAST TO MOVE TOWARDS
THE AREA SATURDAY THEN INLAND SUNDAY. AHEAD OF THE SHORTWAVE
EXPECT SOME SCATTERED SHOWERS TO DEVELOP SATURDAY AFTERNOON AND
EVENING. A SLIGHT CHANCE OF THUNDERSTORMS IS ALSO
POSSIBLE...MAINLY EAST OF THE CASCADES ON SATURDAY. BY SUNDAY
MODELS INDICATE CONTINUED MOISTURE AND INCREASING INSTABILITY.
EXPECT MOST AREAS TO SEE A CHANCE FOR SHOWERS SUNDAY WITH
THUNDERSTORMS POSSIBLE IN THE AFTERNOON AND EVENING FROM THE
CASCADES EAST.
.LONG TERM...MEMORIAL DAY THROUGH THURSDAY...CONFIDENCE REMAINS HIGH
IN THE OVERALL WEATHER PATTERN IN THE EXTENDED AS GEFS/ECMWF
ENSEMBLE MEANS BOTH FOCUS A TROUGH OVER THE WESTERN UNITED STATES
WITH BELOW NORMAL HEIGHTS. WHILE IT WON`T BE AS COOL AS IT WAS
EARLIER THIS WEEK, TEMPERATURES OVERALL FOR THE PERIOD WILL LIKELY
REMAIN SLIGHTLY BELOW NORMAL. THAT TRANSLATES TO UPPER 60S AND LOWER
70S FOR HIGHS IN MEDFORD. TIMING AND STRENGTH DETAILS OF INDIVIDUAL
SHORT WAVES MOVING INTO THE NORTHWEST WILL BE DIFFICULT, BUT THE
STRONGEST IS LIKELY TO ARRIVE AT THE COAST MONDAY MORNING, THEN PUSH
INLAND DURING THE AFTERNOON/EVENING. THE 00Z DETERMINISTIC RUN OF
THE ECMWF WAS WEAKER AND FARTHER SOUTH WITH THIS FEATURE, BUT THE
12Z RUN HAS COME MORE IN LINE WITH THE 12Z GFS (THOUGH STILL IS A
BIT WEAKER AND FARTHER SOUTH). EVEN SO, FELT CONFIDENT ENOUGH HERE
TO INCREASE POPS DURING THIS TIME, SINCE THAT IS WHERE THE FOCUS OF
PRECIP LIKELY WILL BE. HEIGHTS WILL RISE A BIT TUESDAY, BUT REMAIN
BELOW NORMAL, SO HAVE MAINTAINED SLIGHT CHC TO CHC POPS. MODELS
SHOWING ANOTHER SHORT WAVE APPROACHING THE COAST WEDNESDAY INTO
THURSDAY IN THE MOIST WESTERLY ONSHORE FLOW. THIS SHOULD KEEP THE
PROBABILITY OF SHOWERS HIGHEST ALONG AND WEST OF THE CASCADES.
BEYOND THAT, THE GFS ENSEMBLES CARVE ANOTHER DEEP TROUGH/CLOSED LOW
OVER THE AREA/JUST OFFSHORE NEXT WEEKEND, WHILE THE ECMWF IS FLATTER
AND MORE ZONAL. SPILDE
&&
.AVIATION...LOW PRESSURE TO THE NORTH WILL CONTINUE TO BRING SOME
LIGHT RAIN ALONG WITH A MIX OF VFR AND MVFR NORTH OF THE UMPQUA
DIVIDE AND ALONG THE NORTH COAST THE REST OF THIS AFTERNOON
THROUGH TONIGHT. MOSTLY VFR IS EXPECTED SOUTH OF THE UMPQUA DIVIDE
THROUGH TONIGHT, BUT WE CANNOT RULE OUT SOME MVFR IN ISOLATED
HEAVIER SHOWERS THIS AFTERNOON, THEN AGAIN TOWARD SUNRISE OVER THE
VALLEYS. PARTIAL MOUNTAIN OBSCURATION IS ALSO LIKELY, ESPECIALLY
ACROSS THE NORTHERN HALF OF THE CWA. EAST OF THE CASCADES,
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING THIS
AFTERNOON...MOST NUMEROUS ALONG AND EAST OF WINTER RIM SOUTHWARD
TO THE WARNERS. SOME MVFR CIGS ARE LIKELY IN THE HEAVIER SHOWERS,
BUT THESE WILL TEND TO DIMINISH AFTER SUNSET WITH VFR PREVAILING
ONCE AGAIN. SPILDE
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM PDT FRIDAY
FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PDT FRIDAY
FOR PZZ350.
$$
CC
000
FXUS66 KMFR 231556
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
856 AM PDT THU MAY 23 2013
.SHORT TERM...THE UPPER LOW REMAINS OVER THE AREA TODAY. A
SHORTWAVE IS BRINGING SCATTERED SHOWERS EAST OF THE CASCADES WHILE
CONTINUED ONSHORE MOISTURE IS BRINGING ISOLATED SHOWERS TO WEST
SIDE LOCATIONS. A VORT MAX ASSOCIATED WITH UPPER LOW SHIFTS
SOUTH AND INTO THE SOUTHERN OREGON COAST BY LATE THIS AFTERNOON
INTO THE EVENING. SHOWERS ARE EXPECTED TO INCREASE DURING THE
AFTERNOON FOR AREAS FROM THE SOUTHERN OREGON CASCADES WEST...WITH
GREATEST SHOWERS ACROSS COOS AND DOUGLAS COUNTY AREAS. MODELS ARE
TRACKING THIS FEATURE INLAND OVER NORTHERN PORTIONS OF THE CWA
THIS EVENING AND TONIGHT. SOME MODERATE RAIN IS POSSIBLE AS THIS
DISTURBANCE MOVES INLAND ESPECIALLY IS THE COOS AND DOUGLAS AREAS.
ALSO MODELS CONTINUE TO SHOW WEAK INSTABILITY OVER PORTIONS OF THE
EAST SIDE MAINLY IN LAKE COUNTY...SO HAVE CONTINUED THE MENTION
THAT ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THIS AREA THIS
AFTERNOON AND EVENING.
DURING THE DAY FRIDAY EXPECT DECREASING SHOWERS AS THE CORE OF THE
UPPER FINALLY MOVES NORTHEAST. WE WILL STILL HAVE A BROAD TROUGH
OVER THE REGION THOUGH BRINGING MILD TEMPERATURES WITH HIGHS
EXPECTED NEAR NORMAL. ANOTHER DISTURBANCE IS FORECAST TO MOVE
INLAND SATURDAY WITH ANOTHER ROUND OF SCATTERED SHOWERS POSSIBLE
SATURDAY AFTERNOON AND EVENING. A SLIGHT CHANCE OF THUNDERSTORMS
EAST OF THE CASCADES IS ALSO POSSIBLE SATURDAY.
&&
.AVIATION...MOISTURE WILL CONTINUE TO BRING SCATTERED SHOWERS TO
THE COAST AND INLAND TO THE SOUTHERN OREGON CASCADES WITH AREAS OF
MVFR CIGS THIS MORNING...INCLUDING AT KMFR...BECOMING MAINLY VFR
BY LATE MORNING. MOUNTAIN OBSCURATION WILL BE FAIRLY WIDESPREAD
TODAY. TO THE EAST OF THE CASCADES LIGHT RAIN AND SNOW SHOWERS
WILL BRING AREAS OF MVFR CIGS THIS MORNING BUT CONDITIONS WILL
IMPROVE TO MAINLY VFR IN THE LATE MORNING...INCLUDING AT KLMT. BY
LATE THIS AFTERNOON ANOTHER DISTURBANCE WILL FIRE OFF MORE SHOWERS
LEADING TO AREAS OF MVFR CIGS ACROSS THE FORECAST AREA. /FB
&&
.PREV DISCUSSION... /ISSUED 313 AM PDT THU MAY 23 2013/
DISCUSSION...CURRENT WATER VAPOR IMAGE SHOWS THE UPPER LOW SPINNING
NEAR THE OREGON/WASHINGTON BORDER AND THIS IS EXPECTED TO CONTINUE
THROUGH FRIDAY MORNING BEFORE WEAKENING AND LIFTING NORTHEAST INTO
WASHINGTON STATE FRIDAY AFTERNOON. A WEAK UPPER TROF REMAINS OVER
THE FORECAST AREA FRIDAY NIGHT THROUGH SATURDAY.
PRECIPITATION HAS DECREASED AND ENDED DURING THE OVERNIGHT HOURS.
HOWEVER EXPECT SHOWERS TO INCREASE AGAIN LATE WITH A SERIES OF
SHORTWAVES ROTATING AROUND THE UPPER LOW. MOST OF THE SHOWERS SHOULD
BE CONCENTRATED ALONG AND WEST OF THE CASCADES AND NORTHERN KLAMATH
AND LAKE COUNTIES AND MORE ISOLATED IN NORTHERN CAL. THERE MAY BE
ENOUGH INSTABILITY FOR ISOLATED THUNDERSTORMS EAST OF THE CASCADES
IN THE AFTERNOON...BUT THIS WILL BE THE EXCEPTION. MOST HOURS AND
LOCATIONS WILL HAVE JUST INSTABILITY SHOWERS.
ANOTHER SHORTWAVE ROTATING AROUND THE UPPER LOW IS EXPECTED TO MOVE
INTO THE NORTHWEST PART OF THE FORECAST AREA TONIGHT RESULTING IN A
CONTINUATION OF SHOWERS MAINLY NORTH OF THE UMPQUA DIVIDE AND
CASCADES NEAR AND NORTH OF CRATER LAKE. ELSEWHERE SHOWERS ARE
EXPECTED TO BE MORE ISOLATED. PLENTY OF CLOUD COVER REMAINS OVER THE
AREA WHICH WILL LIMIT THE AMOUNT OF COOLING AT NIGHT. NOT AS
CONFIDENT WE`LL GET A SUSTAINED PERIOD OF FREEZING TEMPERATURES IN
THE KLAMATH BASIN AND SHASTA VALLEY.
THE UPPER LOW WILL MOVE NORTHEAST INTO WASHINGTON STATE FRIDAY AND
AS IT DOES SHOWERS WILL DECREASE FROM SOUTH TO NORTH WITH MOST
EXITING THE FORECAST AREA BY FRIDAY EVENING. WE`LL CATCH A BREAK IN
SHOWER ACTIVITY FRIDAY NIGHT.
ANOTHER...BUT WEAKER UPPER TROF SWINGS INTO THE AREA SATURDAY
MORNING WITH SHOWERS EXPECTED TO INCREASE WEST OF THE CASCADES. THE
NAM SHOWS QPF BREAKING OUT EAST OF THE CASCADES IN THE AFTERNOON
WHICH IS MOST LIKELY A RESULT OF INCREASING INSTABILITY AND WEAK
SHORTWAVES PASSING BY.
WEAK TROFING REMAINS OVER THE AREA SUNDAY. HOWEVER THE GFS SUGGEST
THE TROF AXIS WILL MOVE EAST IN THE AFTERNOON WITH WEAK RIDGING
BUILDING FROM THE WEST. CONFIDENCE IS NOT HIGH ON THE GFS SOLUTION
THEREFORE WE`LL KEEP THE CHANCE OF SHOWERS IN THROUGHOUT THE DAY.
-PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
MORNING FOR PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
EVENING FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
EVENING FOR PZZ350.
$$
CC
000
FXUS66 KMFR 231013
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
313 AM PDT THU MAY 23 2013
.DISCUSSION...CURRENT WATER VAPOR IMAGE SHOWS THE UPPER LOW SPINNING
NEAR THE OREGON/WASHINGTON BORDER AND THIS IS EXPECTED TO CONTINUE
THROUGH FRIDAY MORNING BEFORE WEAKENING AND LIFTING NORTHEAST INTO
WASHINGTON STATE FRIDAY AFTERNOON. A WEAK UPPER TROF REMAINS OVER
THE FORECAST AREA FRIDAY NIGHT THROUGH SATURDAY.
PRECIPITATION HAS DECREASED AND ENDED DURING THE OVERNIGHT HOURS.
HOWEVER EXPECT SHOWERS TO INCREASE AGAIN LATE WITH A SERIES OF
SHORTWAVES ROTATING AROUND THE UPPER LOW. MOST OF THE SHOWERS SHOULD
BE CONCENTRATED ALONG AND WEST OF THE CASCADES AND NORTHERN KLAMATH
AND LAKE COUNTIES AND MORE ISOLATED IN NORTHERN CAL. THERE MAY BE
ENOUGH INSTABILITY FOR ISOLATED THUNDERSTORMS EAST OF THE CASCADES
IN THE AFTERNOON...BUT THIS WILL BE THE EXCEPTION. MOST HOURS AND
LOCATIONS WILL HAVE JUST INSTABILITY SHOWERS.
ANOTHER SHORTWAVE ROTATING AROUND THE UPPER LOW IS EXPECTED TO MOVE
INTO THE NORTHWEST PART OF THE FORECAST AREA TONIGHT RESULTING IN A
CONTINUATION OF SHOWERS MAINLY NORTH OF THE UMPQUA DIVIDE AND
CASCADES NEAR AND NORTH OF CRATER LAKE. ELSEWHERE SHOWERS ARE
EXPECTED TO BE MORE ISOLATED. PLENTY OF CLOUD COVER REMAINS OVER THE
AREA WHICH WILL LIMIT THE AMOUNT OF COOLING AT NIGHT. NOT AS
CONFIDENT WE`LL GET A SUSTAINED PERIOD OF FREEZING TEMPERATURES IN
THE KLAMATH BASIN AND SHASTA VALLEY.
THE UPPER LOW WILL MOVE NORTHEAST INTO WASHINGTON STATE FRIDAY AND
AS IT DOES SHOWERS WILL DECREASE FROM SOUTH TO NORTH WITH MOST
EXITING THE FORECAST AREA BY FRIDAY EVENING. WE`LL CATCH A BREAK IN
SHOWER ACTIVITY FRIDAY NIGHT.
ANOTHER...BUT WEAKER UPPER TROF SWINGS INTO THE AREA SATURDAY
MORNING WITH SHOWERS EXPECTED TO INCREASE WEST OF THE CASCADES. THE
NAM SHOWS QPF BREAKING OUT EAST OF THE CASCADES IN THE AFTERNOON
WHICH IS MOST LIKELY A RESULT OF INCREASING INSTABILITY AND WEAK
SHORTWAVES PASSING BY.
WEAK TROFING REMAINS OVER THE AREA SUNDAY. HOWEVER THE GFS SUGGEST
THE TROF AXIS WILL MOVE EAST IN THE AFTERNOON WITH WEAK RIDGING
BUILDING FROM THE WEST. CONFIDENCE IS NOT HIGH ON THE GFS SOLUTION
THEREFORE WE`LL KEEP THE CHANCE OF SHOWERS IN THROUGHOUT THE DAY.
-PETRUCELLI
&&
.AVIATION...
BASED ON THE 23/06Z TAF CYCLE.
A PERSISTENT STREAM OF MOISTURE WILL CONTINUE TO MOVE INTO THE NORTH
COAST, UMPQUA, AND NORTH CASCADES THIS MORNING. THIS WILL KEEP
LIGHT RAIN GOING ALONG THE COAST WITH SCATTERED TO NUMEROUS
SHOWERS INLAND TO THE CASCADES WITH MVFR CIGS AND OCCASIONAL MVFR
VIS OVER THIS AREA. MOUNTAIN OBSCURATION WILL ALSO BE FAIRLY
WIDESPREAD ON THE WEST SIDE. SHOWERS WITH MVFR CIGS ARE ALSO
ONGOING IN THE KLAMATH BASIN, BUT THESE SHOWERS WILL DECREASE
AROUND DAYBREAK. SHOWERS ARE MUCH MORE ISOLATED WITH GENERAL VFR
CONDITIONS ELSEWHERE ON THE EAST SIDE AND CALIFORNIA. -WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR ORZ029.
CA...FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ084.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
UNTIL 11 PM PDT THIS EVENING FOR PZZ350.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
MORNING FOR PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
EVENING FOR PZZ370-376.
$$
000
FXUS66 KMFR 230333
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
833 PM PDT WED MAY 22 2013
.DISCUSSION...ALREADY MADE AN UPDATE THIS EVENING, PRIMARILY TO
RAISE POPS ALONG THE COOS COAST ACROSS THE UMPQUA INTO THE NORTH
CASCADES. A BROAD UPPER LOW CONTINUES TO SPIN OVER THE PACNW THIS
EVENING AND IS CURRENTLY CENTERED OVER SW WASHINGTON. A STEADY
STREAM OF MOISTURE CONTINUES TO IMPACT NORTHERN SECTION OF MY
FORECAST AREA. WEBCAMS SHOW WET CONDITIONS AND MANY SITES FROM
COOS COUNTY EAST INTO THE CASCADES CONTINUE TO RECORD
PRECIPITATION, AND THIS WAS THE PURPOSE OF THE UPDATE. FURTHER
SOUTH, SHOWERS ARE MORE ISOLATED BUT BECAUSE OF A DEEP NEARLY
SATURATED PROFILE, THEY ARE COMING DOWN HEAVY AT TIMES. SHOWERS
ARE EVEN MORE ISOLATED EAST OF THE CASCADES AND IN CALIFORNIA AND
AS A RESULT, I`VE KEPT POPS MUCH LOWER OVER THERE.
WE WILL HAVE TO KEEP AN EYE ON ANY IMPULSES ROTATING AROUND THE
UPPER LOW WHICH COULD INCREASE SHOWER ACTIVITY. BUT FOR THE TIME
BEING, IT LOOKS AS IF NORTHERN AREAS WILL REMAIN THE FOCUS AND THE
REST OF US WILL BE DODGING SPOTTIER ACTIVITY. ALL AREAS WILL
REMAIN MUCH COOLER THAN NORMAL FOR THE NEXT SEVERAL DAYS THOUGH.
CLOUDS WILL KEEP US FROM SEEING ANY FROST/FREEZE IMPACTS OVER WEST
SIDE AG AREAS, BUT SOME EAST SIDE AND NORCAL GROWING AREAS ARE
CURRENTLY UNDER FREEZE WARNINGS AND FROST ADVISORIES, AND I SEE NO
COMPELLING REASON TO CHANGE THOSE. -WRIGHT
&&
.AVIATION...AREAS OF MVFR CIGS AND AREAS OF OBSCURED MOUNTAINS ARE
EXPECTED THROUGH THE EVENING. AREAS OF MVFR CIGS AND
VISIBILITIES WILL PERSIST NEAR THE COAST AND IN THE UMPQUA BASIN
LATE TONIGHT THROUGH THURSDAY MORNING. OTHERWISE...CONDITIONS WILL
IMPROVE TO VFR LATE TONIGHT. ANOTHER DISTURBANCE WILL REACH THE
COAST BY THURSDAY AFTERNOON...AND WILL LIKELY PUSH MORE
PRECIPITATION AND AREAS OF MVFR INTO THE REGION. -BPN
&&
.PREV DISCUSSION... /ISSUED 313 PM PDT WED MAY 22 2013/
SHORT TERM...AN UPPER LOW WILL REMAIN OVER THE REGION THROUGH
FRIDAY...WEAKENING AND SHIFTING NORTH SLIGHTLY ON SATURDAY. THIS
LOW WILL GRADUALLY FILL AND THE AIR MASS WILL GRADUALLY WARM.
CONTINUED MOISTURE AND SHORTWAVES WILL MOVE INTO THE CWA OVER THE
NEXT FEW DAYS AND BRING SHOWERS. THE PREFERRED AREA FOR SHOWER
ACTIVITY WILL BE ACROSS THE COAST AND THE UMPQUA AS WELL AS THE
SOUTHERN OREGON CASCADES WITH AREAS OF SHOWERS MOVING INTO OTHER
WEST SIDE LOCATIONS AND EAST OF THE CASCADES AT TIMES.
A SHORTWAVE IS MOVING INLAND THIS AFTERNOON AND EVENING AND IS
BRINGING SCATTERED SHOWERS TO AREAS FROM THE CASCADES WEST.
SHOWER ACTIVITY IS EXPECTED TO INCREASE ACROSS THE WEST SIDE IN
THIS AFTERNOON AND EVENING AND SPREAD INTO SOME EAST SIDE LOCATIONS AS
WELL. SOME OF THE SHOWERS MAY BRING SMALL HAIL AND GUSTY WINDS
THIS AFTERNOON INTO THIS EVENING. MODELS SHOW SOME MARGINAL
INSTABILITY IN NORTHERN LAKE COUNTY. EXPECT MAINLY SCATTERED
SHOWERS TO DEVELOP THERE BUT THINK THE CHANCE FOR ANY
THUNDERSTORMS IS LOW.
SHOWER ACTIVITY IS EXPECTED TO CONTINUE INTO THE EVENING FOR MANY
LOCATIONS WITH SHOWERS DECREASING OVERNIGHT. COLD OVERNIGHT
TEMPERATURES ARE EXPECTED AGAIN TONIGHT INTO THURSDAY MORNING.
SKIES WILL LIKELY STAY CLOUDY OVERNIGHT WITH SOME PARTIAL
CLEARING OVER INLAND AREAS DURING THE EARLY MORNING. TEMPERATURES
THURSDAY MORNING WILL LIKELY BE SIMILAR OR JUST A COUPLE DEGREES
WARMER THAN THIS MORNING. PARTIAL CLEARING THOUGH MAY ALLOW MORE
FROST FORMATION THURSDAY MORNING. HAVE INCLUDED MENTION OF PATCHY
FROST IN THE WESTERN OREGON VALLEYS INCLUDING THE ROGUE AND
ILLINOIS VALLEYS AND AREAS OF FROST INTO THE SHASTA VALLEY IN
CALIFORNIA. OVER THE KLAMATH BASIN EXPECT FREEZING AND BELOW
FREEZING CONDITIONS.
ON THURSDAY...EXPECT SOME SCATTERED SHOWERS DURING THE DAY. THEN
MODELS SHOW INCREASED SHOWER ACTIVITY DURING THE EVENING AND
CONTINUING INTO FRIDAY MORNING AS A MODERATE VORT MAX ASSOCIATED
WITH THE UPPER LOW MOVES INTO THE AREA. THE BEST CHANCE FOR SHOWERS
WILL BE FROM THE SOUTHERN OREGON CASCADES WEST WITH ISOLATED TO
SCATTERED SHOWERS EAST OF THE CASCADES AND INTO PORTIONS OF
NORTHERN CALIFORNIA.
SHOWERS ARE EXPECTED TO DECREASE FRIDAY AFTERNOON AND EVENING AS
THE SHORTWAVE MOVES NORTHEAST AND OUT THE AREA. THE UPPER
TROUGH REMAINS OVER THE REGION FRIDAY NIGHT AND SATURDAY...ALTHOUGH
WEAKER AND CENTERED FURTHER NORTH. THIS WILL BRING THE POTENTIAL
FOR ADDITIONAL AREAS OF SCATTERED SHOWERS ON SATURDAY. MODELS HAVE
TRENDED LOWER ON THE SHOWER ACTIVITY THOUGH SO HAVE LOWERED THE
CHANCE OF PRECIPITATION FOR SATURDAY. WEAK INSTABILITY STILL IS
PRESENT EAST OF THE CASCADES SO HAVE KEPT A SLIGHT CHANCE FOR
THUNDERSTORMS...MAINLY IN LAKE COUNTY...SATURDAY AFTERNOON AND
EVENING.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY NIGHT...
THE 12Z GFS AND ECMWF STILL AGREE ON THE CHARACTER OF THE LONG TERM
FORECAST. THE UPPER LEVEL PATTERN SHOWS A CONTINUATION OF A LONGWAVE
TROUGH WITH A SERIES OF DISTURBANCES TO AFFECT OUR REGION FROM THE
WEEKEND ALL THE WAY THROUGH NEXT WEEK. TEMPERATURES WILL MOSTLY
RANGE FROM SLIGHTLY BELOW NORMAL TO NEAR NORMAL THROUGH THE PERIOD.
DESPITE THE AGREEMENT AND HIGH CONFIDENCE ON THE BIG PICTURE...THE
GFS AND ECMWF SOLUTIONS BEGIN TO DIVERGE ON SATURDAY AND DIFFERENCES
BECOME SIGNIFICANT ALREADY BY SATURDAY NIGHT. ON SATURDAY NIGHT, THE
EC RETROGRADES THE MAIN UPPER TROUGH TO OFFSHORE OF WASHINGTON WHILE
THE GFS IS MORE SIMILAR TO ITS SOLUTION FROM YESTERDAY WITH THE MAIN
TROUGH MOVING NORTHEAST TO INLAND BRITISH COLUMBIA AND A SECONDARY
LOBE OVER OUR AREA. THE MAIN EFFECT IS THAT THE PROBABILITY OF EAST
SIDE SHOWERS AND A FEW EAST SIDE EVENING THUNDERSTORMS IS HIGHER WITH
THE GFS WHILE THE WESTERLY FLOW FROM THE EC WOULD FAVOR SCATTERED
SHOWERS ON THE WEST SIDE OF THE CASCADES.
THE GFS SOLUTION IS WARMER THAN THE EC ON SUNDAY. I WENT WITH A
MODEL BLEND FOR THE TEMPERATURE FORECAST. BOTH MODELS HAVE SOME
VERSION OF A WEAK FRONT CROSSING THE AREA. THE EC DEPICTED FRONT
WOULD BE STRONGER BUT FOCUSED NORTH OF THE UMPQUA DIVIDE WHILE THE
GFS SOLUTION WOULD BRING MORE WIDESPREAD BUT MAINLY LIGHT SHOWERS.
THE MODEL SOLUTIONS FOR MEMORIAL DAY HAVE CHANGED SIGNIFCANTLY WITH
THE GFS UPPER LEVEL PATTERN BECOMING MORE PROGRESSIVE AND THE ECMWF
LESS PROGRESSIVE. IN THE ECMWF CASE...THE UPPER TROUGH LINGERS
OVER THE PACIFIC NORTHWEST WITH A COLD FRONT MOVING SOUTHEAST
TOWARD OUR AREA WHILE THE GFS SHOWS BRIEF WEAK RIDGING SUNDAY
NIGHT THEN THE NEXT UPPER TROUGH ALREADY APPROACHING THE COAST.
THE COMMONALITY IS THAT BOTH MODELS HAVE TRENDED COOLER AND
WETTER. THERE IS STILL A SIZEABLE POSSIBILITY THAT MONDAY MORNING
WILL BE DRY. BUT I HAVE RAISED THE PROBABILITY OF RAIN FOR MONDAY
AND IT REMAINS ABOVE CLIMATOLOGICAL NORMAL THROUGH TUESDAY. A
MOIST ONSHORE FLOW IS FORECAST TO CONTINUE ON WEDNESDAY WITH A
SLIGHT CHANCE TO CHANCE OF LIGHT SHOWERS. /DW
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR ORZ029.
CA...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR CAZ084.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
UNTIL 11 PM PDT THURSDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THURSDAY
FOR PZZ370-376.
$$
000
FXUS66 KMFR 222217 CCA
AFDMFR
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MEDFORD OR
313 PM PDT WED MAY 22 2013
.SHORT TERM...AN UPPER LOW WILL REMAIN OVER THE REGION THROUGH
FRIDAY...WEAKENING AND SHIFTING NORTH SLIGHTLY ON SATURDAY. THIS
LOW WILL GRADUALLY FILL AND THE AIR MASS WILL GRADUALLY WARM.
CONTINUED MOISTURE AND SHORTWAVES WILL MOVE INTO THE CWA OVER THE
NEXT FEW DAYS AND BRING SHOWERS. THE PREFERRED AREA FOR SHOWER
ACTIVITY WILL BE ACROSS THE COAST AND THE UMPQUA AS WELL AS THE
SOUTHERN OREGON CASCADES WITH AREAS OF SHOWERS MOVING INTO OTHER
WEST SIDE LOCATIONS AND EAST OF THE CASCADES AT TIMES.
A SHORTWAVE IS MOVING INLAND THIS AFTERNOON AND EVENING AND IS
BRINGING SCATTERED SHOWERS TO AREAS FROM THE CASCADES WEST.
SHOWER ACTIVITY IS EXPECTED TO INCREASE ACROSS THE WEST SIDE IN
THIS AFTERNOON AND EVENING AND SPREAD INTO SOME EAST SIDE LOCATIONS AS
WELL. SOME OF THE SHOWERS MAY BRING SMALL HAIL AND GUSTY WINDS
THIS AFTERNOON INTO THIS EVENING. MODELS SHOW SOME MARGINAL
INSTABILITY IN NORTHERN LAKE COUNTY. EXPECT MAINLY SCATTERED
SHOWERS TO DEVELOP THERE BUT THINK THE CHANCE FOR ANY
THUNDERSTORMS IS LOW.
SHOWER ACTIVITY IS EXPECTED TO CONTINUE INTO THE EVENING FOR MANY
LOCATIONS WITH SHOWERS DECREASING OVERNIGHT. COLD OVERNIGHT
TEMPERATURES ARE EXPECTED AGAIN TONIGHT INTO THURSDAY MORNING.
SKIES WILL LIKELY STAY CLOUDY OVERNIGHT WITH SOME PARTIAL
CLEARING OVER INLAND AREAS DURING THE EARLY MORNING. TEMPERATURES
THURSDAY MORNING WILL LIKELY BE SIMILAR OR JUST A COUPLE DEGREES
WARMER THAN THIS MORNING. PARTIAL CLEARING THOUGH MAY ALLOW MORE
FROST FORMATION THURSDAY MORNING. HAVE INCLUDED MENTION OF PATCHY
FROST IN THE WESTERN OREGON VALLEYS INCLUDING THE ROGUE AND
ILLINOIS VALLEYS AND AREAS OF FROST INTO THE SHASTA VALLEY IN
CALIFORNIA. OVER THE KLAMATH BASIN EXPECT FREEZING AND BELOW
FREEZING CONDITIONS.
ON THURSDAY...EXPECT SOME SCATTERED SHOWERS DURING THE DAY. THEN
MODELS SHOW INCREASED SHOWER ACTIVITY DURING THE EVENING AND
CONTINUING INTO FRIDAY MORNING AS A MODERATE VORT MAX ASSOCIATED
WITH THE UPPER LOW MOVES INTO THE AREA. THE BEST CHANCE FOR SHOWERS
WILL BE FROM THE SOUTHERN OREGON CASCADES WEST WITH ISOLATED TO
SCATTERED SHOWERS EAST OF THE CASCADES AND INTO PORTIONS OF
NORTHERN CALIFORNIA.
SHOWERS ARE EXPECTED TO DECREASE FRIDAY AFTERNOON AND EVENING AS
THE SHORTWAVE MOVES NORTHEAST AND OUT THE AREA. THE UPPER
TROUGH REMAINS OVER THE REGION FRIDAY NIGHT AND SATURDAY...ALTHOUGH
WEAKER AND CENTERED FURTHER NORTH. THIS WILL BRING THE POTENTIAL
FOR ADDITIONAL AREAS OF SCATTERED SHOWERS ON SATURDAY. MODELS HAVE
TRENDED LOWER ON THE SHOWER ACTIVITY THOUGH SO HAVE LOWERED THE
CHANCE OF PRECIPITATION FOR SATURDAY. WEAK INSTABILITY STILL IS
PRESENT EAST OF THE CASCADES SO HAVE KEPT A SLIGHT CHANCE FOR
THUNDERSTORMS...MAINLY IN LAKE COUNTY...SATURDAY AFTERNOON AND
EVENING.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY NIGHT...
THE 12Z GFS AND ECMWF STILL AGREE ON THE CHARACTER OF THE LONG TERM
FORECAST. THE UPPER LEVEL PATTERN SHOWS A CONTINUATION OF A LONGWAVE
TROUGH WITH A SERIES OF DISTURBANCES TO AFFECT OUR REGION FROM THE
WEEKEND ALL THE WAY THROUGH NEXT WEEK. TEMPERATURES WILL MOSTLY
RANGE FROM SLIGHTLY BELOW NORMAL TO NEAR NORMAL THROUGH THE PERIOD.
DESPITE THE AGREEMENT AND HIGH CONFIDENCE ON THE BIG PICTURE...THE
GFS AND ECMWF SOLUTIONS BEGIN TO DIVERGE ON SATURDAY AND DIFFERENCES
BECOME SIGNIFICANT ALREADY BY SATURDAY NIGHT. ON SATURDAY NIGHT, THE
EC RETROGRADES THE MAIN UPPER TROUGH TO OFFSHORE OF WASHINGTON WHILE
THE GFS IS MORE SIMILAR TO ITS SOLUTION FROM YESTERDAY WITH THE MAIN
TROUGH MOVING NORTHEAST TO INLAND BRITISH COLUMBIA AND A SECONDARY
LOBE OVER OUR AREA. THE MAIN EFFECT IS THAT THE PROBABILITY OF EAST
SIDE SHOWERS AND A FEW EAST SIDE EVENING THUNDERSTORMS IS HIGHER WITH
THE GFS WHILE THE WESTERLY FLOW FROM THE EC WOULD FAVOR SCATTERED
SHOWERS ON THE WEST SIDE OF THE CASCADES.
THE GFS SOLUTION IS WARMER THAN THE EC ON SUNDAY. I WENT WITH A
MODEL BLEND FOR THE TEMPERATURE FORECAST. BOTH MODELS HAVE SOME
VERSION OF A WEAK FRONT CROSSING THE AREA. THE EC DEPICTED FRONT
WOULD BE STRONGER BUT FOCUSED NORTH OF THE UMPQUA DIVIDE WHILE THE
GFS SOLUTION WOULD BRING MORE WIDESPREAD BUT MAINLY LIGHT SHOWERS.
THE MODEL SOLUTIONS FOR MEMORIAL DAY HAVE CHANGED SIGNIFCANTLY WITH
THE GFS UPPER LEVEL PATTERN BECOMING MORE PROGRESSIVE AND THE ECMWF
LESS PROGRESSIVE. IN THE ECMWF CASE...THE UPPER TROUGH LINGERS
OVER THE PACIFIC NORTHWEST WITH A COLD FRONT MOVING SOUTHEAST
TOWARD OUR AREA WHILE THE GFS SHOWS BRIEF WEAK RIDGING SUNDAY
NIGHT THEN THE NEXT UPPER TROUGH ALREADY APPROACHING THE COAST.
THE COMMONALITY IS THAT BOTH MODELS HAVE TRENDED COOLER AND
WETTER. THERE IS STILL A SIZEABLE POSSIBILITY THAT MONDAY MORNING
WILL BE DRY. BUT I HAVE RAISED THE PROBABILITY OF RAIN FOR MONDAY
AND IT REMAINS ABOVE CLIMATOLOGICAL NORMAL THROUGH TUESDAY. A
MOIST ONSHORE FLOW IS FORECAST TO CONTINUE ON WEDNESDAY WITH A
SLIGHT CHANCE TO CHANCE OF LIGHT SHOWERS. /DW
&&
.AVIATION...A WEAKENING DISTURBANCE IS MOVING ACROSS THE AREA
THIS AFTERNOON. SCATTERED SHOWERS...AREAS OF MVFR CIGS AND AREAS
OF OBSCURED MOUNTAINS ARE EXPECTED THROUGH THE EVENING. AREAS OF
MVFR CIGS WILL PERSIST NEAR THE COAST AND IN THE UMPQUA BASIN LATE
TONIGHT THROUGH THURSDAY MORNING. OTHERWISE...CONDITIONS WILL
IMPROVE TO VFR LATE TONIGHT. ANOTHER DISTURBANCE WILL REACH THE
COAST BY THURSDAY AFTERNOON.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR ORZ029.
CA...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR CAZ084.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
11 PM PDT THURSDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THURSDAY
FOR PZZ370-376.
$$
CC
000
FXUS66 KMFR 222157
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
257 PM PDT WED MAY 22 2013
.SHORT TERM...AN UPPER LOW WILL REMAIN OVER THE REGION THROUGH
FRIDAY...WEAKENING AND SHIFTING NORTH SLIGHTLY ON SATURDAY. THIS
LOW WILL GRADUALLY FILL AND THE AIR MASS WILL GRADUALLY WARM.
CONTINUED MOISTURE AND SHORTWAVES WILL MOVE INTO THE CWA OVER THE
NEXT FEW DAYS AND BRING SHOWERS. THE PREFERRED AREA FOR SHOWER
ACTIVITY WILL BE ACROSS THE COAST AND THE UMPQUA AS WELL AS THE
SOUTHERN OREGON CASCADES WITH AREAS OF SHOWERS MOVING INTO OTHER
WEST SIDE LOCATIONS AND EAST OF THE CASCADES AT TIMES.
A SHORTWAVE IS MOVING INLAND THIS AFTERNOON AND EVENING AND IS
BRINGING SCATTERED SHOWERS TO AREAS FROM THE CASCADES WEST.
SHOWER ACTIVITY IS EXPECTED TO INCREASE ACROSS THE WEST SIDE IN
THIS AFTERNOON AND EVENING AND SPREAD INTO SOME EAST SIDE LOCATIONS AS
WELL. SOME OF THE SHOWERS MAY BRING SMALL HAIL AND GUSTY WINDS
THIS AFTERNOON INTO THIS EVENING. MODELS SHOW SOME MARGINAL
INSTABILITY IN NORTHERN LAKE COUNTY. EXPECT MAINLY SCATTERED
SHOWERS TO DEVELOP THERE BUT THINK THE CHANCE FOR ANY
THUNDERSTORMS IS LOW.
SHOWER ACTIVITY IS EXPECTED TO CONTINUE INTO THE EVENING FOR MANY
LOCATIONS WITH SHOWERS DECREASING OVERNIGHT. COLD OVERNIGHT
TEMPERATURES ARE EXPECTED AGAIN TONIGHT INTO THURSDAY MORNING.
SKIES WILL LIKELY STAY CLOUDY OVERNIGHT WITH SOME PARTIAL
CLEARING OVER INLAND AREAS DURING THE EARLY MORNING. TEMPERATURES
THURSDAY MORNING WILL LIKELY BE SIMILAR OR JUST A COUPLE DEGREES
WARMER THAN THIS MORNING. PARTIAL CLEARING THOUGH MAY ALLOW MORE
FROST FORMATION THURSDAY MORNING. HAVE INCLUDED MENTION OF PATCHY
FROST IN THE WESTERN OREGON VALLEYS INCLUDING THE ROGUE AND
ILLINOIS VALLEYS AND AREAS OF FROST INTO THE SHASTA VALLEY IN
CALIFORNIA. OVER THE KLAMATH BASIN EXPECT FREEZING AND BELOW
FREEZING CONDITIONS.
ON THURSDAY...EXPECT SOME SCATTERED SHOWERS DURING THE DAY. THEN
MODELS SHOW INCREASED SHOWER ACTIVITY DURING THE EVENING AND
CONTINUING INTO FRIDAY MORNING AS A MODERATE VORT MAX ASSOCIATED
WITH THE UPPER LOW MOVES INTO THE AREA. THE BEST CHANCE FOR SHOWERS
WILL BE FROM THE SOUTHERN OREGON CASCADES WEST WITH ISOLATED TO
SCATTERED SHOWERS EAST OF THE CASCADES AND INTO PORTIONS OF
NORTHERN CALIFORNIA.
SHOWERS ARE EXPECTED TO DECREASE FRIDAY AFTERNOON AND EVENING AS
THE SHORTWAVE MOVES NORTHEAST AND OUT THE AREA. THE UPPER
TROUGH REMAINS OVER THE REGION FRIDAY NIGHT AND SATURDAY...ALTHOUGH
WEAKER AND CENTERED FURTHER NORTH. THIS WILL BRING THE POTENTIAL
FOR ADDITIONAL AREAS OF SCATTERED SHOWERS ON SATURDAY. MODELS HAVE
TRENDED LOWER ON THE SHOWER ACTIVITY THOUGH SO HAVE LOWERED THE
CHANCE OF PRECIPITATION FOR SATURDAY. WEAK INSTABILITY STILL IS
PRESENT EAST OF THE CASCADES SO HAVE KEPT A SLIGHT CHANCE FOR
THUNDERSTORMS...MAINLY IN LAKE COUNTY...SATURDAY AFTERNOON AND
EVENING.
.LONG TERM...
&&
.AVIATION...A WEAKENING DISTURBANCE IS MOVING ACROSS THE AREA
THIS AFTERNOON. SCATTERED SHOWERS...AREAS OF MVFR CIGS AND AREAS
OF OBSCURED MOUNTAINS ARE EXPECTED THROUGH THE EVENING. AREAS OF
MVFR CIGS WILL PERSIST NEAR THE COAST AND IN THE UMPQUA BASIN LATE
TONIGHT THROUGH THURSDAY MORNING. OTHERWISE...CONDITIONS WILL
IMPROVE TO VFR LATE TONIGHT. ANOTHER DISTURBANCE WILL REACH THE
COAST BY THURSDAY AFTERNOON.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR ORZ029.
CA...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR CAZ084.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THURSDAY
FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THURSDAY
FOR PZZ370-376.
$$
CC
000
FXUS66 KMFR 221546
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
846 AM PDT WED MAY 22 2013
.SHORT TERM...AN UPPER LOW WILL REMAIN OVER THE AREA TODAY THROUGH
FRIDAY. THIS LOW WILL GRADUALLY FILL AND THE AIR MASS WILL
GRADUALLY WARM. CONTINUED MOISTURE AND SHORTWAVES WILL MOVE INTO
THE AREA OVER THE NEXT FEW DAYS AND BRING SHOWERS. THE PREFERRED
AREA FOR SHOWER ACTIVITY WILL BE ACROSS THE COAST AND THE UMPQUA
AS WELL AS THE SOUTHERN OREGON CASCADES WITH AREAS OF SHOWERS
MOVING INTO OTHER WEST SIDE LOCATIONS AND EAST OF THE CASCADES AT
TIMES.
SATELLITE IMAGERY SHOWS ANOTHER SHORTWAVE OFF THE SOUTHERN OREGON
COAST THIS MORNING. MODELS ARE INDICATING THIS AREA OF SHOWERS WILL MOVE
INLAND AND BRING SHOWERS TO THE COAST AND UMPQUA THIS MORNING
THEN SHOWERS WILL SPREAD FURTHER INLAND ACROSS THE WEST SIDE AND INTO
SOME EAST SIDE LOCATIONS THIS AFTERNOON. SOME OF THE SHOWERS MAY
BRING SMALL HAIL AND GUSTY WINDS THIS AFTERNOON. ALSO MODELS ARE
DEPICTING MARGINAL INSTABILITY IN NORTHERN LAKE COUNTY. EXPECT
MAINLY SCATTERED SHOWERS TO DEVELOP THERE BUT WILL MONITOR FOR
CHANCE OF THUNDERSTORMS LATER THIS AFTERNOON.
SHOWER ACTIVITY IS EXPECTED TO CONTINUE INTO THE EVENING FOR MANY
LOCATIONS WITH SHOWERS DECREASING OVERNIGHT. COLD OVERNIGHT
TEMPERATURES ARE EXPECTED AGAIN TONIGHT INTO THURSDAY MORNING.
SKIES WILL LIKELY STAY CLOUDY OVERNIGHT WITH SOME PARTIAL CLEARING
INLAND DURING THE MORNING. TEMPERATURES THURSDAY MORNING WILL
LIKELY BE SIMILAR OR JUST A COUPLE DEGREES WARMER THAN THIS
MORNING.
THEN ANOTHER ROUND OF INCREASED SHOWERS ACTIVITY IS EXPECT DURING
THE DAY THURSDAY INTO FRIDAY AS ANOTHER SIGNIFICANT SHORTWAVE
MOVES INLAND.
&&
.AVIATION...WIDESPREAD MVFR CIGS WILL CONTINUE AT THE COAST WITH
OCCASIONAL LIFT TO VFR IN THE AFTERNOON. HOWEVER MVFR CIGS WILL
RETURN AGAIN AT THE COAST TONIGHT. INLAND...VFR CONDITIONS ARE
EXPECTED TO PREVAIL TODAY. HOWEVER TEMPORARY MVFR CONDITIONS WITH
PARTIAL MOUNTAIN OBSCURATIONS ARE POSSIBLE NEAR AND WITHIN RAIN
AND SNOW SHOWERS WITH LOCALLY GUSTY WINDS.
&&
.PREV DISCUSSION... /ISSUED 305 AM PDT WED MAY 22 2013/
DISCUSSION...THE UPPER LOW THAT BROUGHT MUCH COOLER
TEMPERATURES...RAIN AND MOUNTAIN SNOW SHOWERS INCLUDING SOME
ACCUMULATING SNOW NEAR CRATER LAKE AND DIAMOND LAKE YESTERDAY WILL
LINGER OVER THE FORECAST AREA FOR THE NEXT COUPLE OF DAYS. THE UPPER
LOW WILL WEAKEN AND MOVE NORTHEAST FRIDAY AND SATURDAY.
PLENTY OF COLD AIR ALOFT IS MOVING OVERHEAD AS EVIDENT BY THE
SATELLITE IMAGE WHICH SHOWS PLENTY OF CUMULUS CLOUDS OVER THE OCEAN
AND ARE MOVING SOUTHEAST INTO SOUTHWEST OREGON. OF NOTE IS SOME
ENHANCEMENT NORTHWEST OF NORTH BEND...SO WE CAN EXPECT SHOWERS TO
INCREASE OVER THE NORTHWEST PART OF THE FORECAST AREA EARLY THIS
MORNING. SNOW LEVELS START OUT AROUND 2800 FEET EARLY THIS MORNING
AND COULD BRIEFLY DROP TO AROUND 2500 FEET IN HEAVIER SHOWERS.
HOWEVER DUE TO WARM ROAD AND GROUND TEMPERATURES I`M EXPECTING WET
SNOW SHOWERS TO MELT. THE EXCEPTION WILL BE AROUND DIAMOND AND
CRATER LAKE AND LAKE OF THE WOODS WHERE A TRACE TO AN INCH OF SLUSHY
SNOW COULD ACCUMULATE PRIOR TO 8 AM PDT. ANYTHING AFTER THAT SHOULD
MELT WITH SNOW LEVELS EXPECTED TO RISE BETWEEN 4000 AND 4500 FEET IN
THE AFTERNOON.
THE UPPER LOW REMAINS OVERHEAD TODAY WITH MULTIPLE SHORTWAVE
ROTATING AROUND IT ALONG WITH COLD AIR ALOFT. THEREFORE WE CAN
EXPECT ALMOST A REPEAT OF YESTERDAY WHERE SHOWERS WILL TEND TO
INCREASE FROM LATE MORNING THROUGH THE AFTERNOON. SOME OF THE
SHOWERS WILL BRING LOCALLY GUSTY WINDS AND SMALL HAIL FROM ABOUT MID
AFTERNOON INTO EARLY THIS EVENING.
SHOWERS WILL DECREASE SOME WEDNESDAY NIGHT...BUT DO NOT EXPECT MUCH
CLEARING TO TAKE PLACE WEST OF THE CASCADES AND TEMPERATURES WILL
REMAIN ABOVE FREEZING. IT WILL BE A CLOSE CALL IN THE KLAMATH BASIN.
THERE IS A CHANCE FOR LESS CLOUD COVER THERE AND ANY CLEARING WILL
ALLOW TEMPERATURES TO DROP QUICKLY. SO WE`LL PLAY IT SAFE AND ISSUE
A FREEZE WATCH FOR LATE TONIGHT/EARLY THURSDAY MORNING.
THE UPPER LOW LINGERS OVER THE AREA THURSDAY WITH SHOWER ACTIVITY AT
A MINIMUM IN THE MORNING THEN INCREASING AGAIN IN THE AFTERNOON. THE
NAM AND GFS SHOW A STRONGER SHORTWAVE SWINGING INTO SOUTHERN OREGON
IN THE AFTERNOON. THIS ALONG WITH INCREASING DAYTIME HEATING COULD
BE ENOUGH TO GENERATE ISOLATED THUNDERSTORMS EAST OF THE CASCADES
LATE IN THE AFTERNOON AND EARLY EVENING.
ANOTHER SHORTWAVE IS EXPECTED TO SWING INTO WESTERN OREGON FRIDAY
MORNING...THEN MOVE NORTHEAST FRIDAY AFTERNOON. SO WE CAN EXPECT
ANOTHER ROUND OF SHOWERS WITH A SLIGHT CHANCE OF ISOLATED STORMS
EAST OF THE CASCADES FRIDAY AFTERNOON. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
ORZ029.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR ORZ029.
CA...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
CAZ084.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ084.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ081.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
EVENING FOR PZZ350.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT THIS
AFTERNOON FOR PZZ356.
HAZARDOUS SEAS WARNING UNTIL 11 AM PDT THIS MORNING FOR PZZ376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ370.
HAZARDOUS SEAS WARNING UNTIL 5 PM PDT THIS AFTERNOON FOR PZZ370.
$$
CC
000
FXUS66 KMFR 221005
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
305 AM PDT WED MAY 22 2013
.DISCUSSION...THE UPPER LOW THAT BROUGHT MUCH COOLER
TEMPERATURES...RAIN AND MOUNTAIN SNOW SHOWERS INCLUDING SOME
ACCUMULATING SNOW NEAR CRATER LAKE AND DIAMOND LAKE YESTERDAY WILL
LINGER OVER THE FORECAST AREA FOR THE NEXT COUPLE OF DAYS. THE UPPER
LOW WILL WEAKEN AND MOVE NORTHEAST FRIDAY AND SATURDAY.
PLENTY OF COLD AIR ALOFT IS MOVING OVERHEAD AS EVIDENT BY THE
SATELLITE IMAGE WHICH SHOWS PLENTY OF CUMULUS CLOUDS OVER THE OCEAN
AND ARE MOVING SOUTHEAST INTO SOUTHWEST OREGON. OF NOTE IS SOME
ENHANCEMENT NORTHWEST OF NORTH BEND...SO WE CAN EXPECT SHOWERS TO
INCREASE OVER THE NORTHWEST PART OF THE FORECAST AREA EARLY THIS
MORNING. SNOW LEVELS START OUT AROUND 2800 FEET EARLY THIS MORNING
AND COULD BRIEFLY DROP TO AROUND 2500 FEET IN HEAVIER SHOWERS.
HOWEVER DUE TO WARM ROAD AND GROUND TEMPERATURES I`M EXPECTING WET
SNOW SHOWERS TO MELT. THE EXCEPTION WILL BE AROUND DIAMOND AND
CRATER LAKE AND LAKE OF THE WOODS WHERE A TRACE TO AN INCH OF SLUSHY
SNOW COULD ACCUMULATE PRIOR TO 8 AM PDT. ANYTHING AFTER THAT SHOULD
MELT WITH SNOW LEVELS EXPECTED TO RISE BETWEEN 4000 AND 4500 FEET IN
THE AFTERNOON.
THE UPPER LOW REMAINS OVERHEAD TODAY WITH MULTIPLE SHORTWAVE
ROTATING AROUND IT ALONG WITH COLD AIR ALOFT. THEREFORE WE CAN
EXPECT ALMOST A REPEAT OF YESTERDAY WHERE SHOWERS WILL TEND TO
INCREASE FROM LATE MORNING THROUGH THE AFTERNOON. SOME OF THE
SHOWERS WILL BRING LOCALLY GUSTY WINDS AND SMALL HAIL FROM ABOUT MID
AFTERNOON INTO EARLY THIS EVENING.
SHOWERS WILL DECREASE SOME WEDNESDAY NIGHT...BUT DO NOT EXPECT MUCH
CLEARING TO TAKE PLACE WEST OF THE CASCADES AND TEMPERATURES WILL
REMAIN ABOVE FREEZING. IT WILL BE A CLOSE CALL IN THE KLAMATH BASIN.
THERE IS A CHANCE FOR LESS CLOUD COVER THERE AND ANY CLEARING WILL
ALLOW TEMPERATURES TO DROP QUICKLY. SO WE`LL PLAY IT SAFE AND ISSUE
A FREEZE WATCH FOR LATE TONIGHT/EARLY THURSDAY MORNING.
THE UPPER LOW LINGERS OVER THE AREA THURSDAY WITH SHOWER ACTIVITY AT
A MINIMUM IN THE MORNING THEN INCREASING AGAIN IN THE AFTERNOON. THE
NAM AND GFS SHOW A STRONGER SHORTWAVE SWINGING INTO SOUTHERN OREGON
IN THE AFTERNOON. THIS ALONG WITH INCREASING DAYTIME HEATING COULD
BE ENOUGH TO GENERATE ISOLATED THUNDERSTORMS EAST OF THE CASCADES
LATE IN THE AFTERNOON AND EARLY EVENING.
ANOTHER SHORTWAVE IS EXPECTED TO SWING INTO WESTERN OREGON FRIDAY
MORNING...THEN MOVE NORTHEAST FRIDAY AFTERNOON. SO WE CAN EXPECT
ANOTHER ROUND OF SHOWERS WITH A SLIGHT CHANCE OF ISOLATED STORMS
EAST OF THE CASCADES FRIDAY AFTERNOON. -PETRUCELLI
&&
.AVIATION...
BASED ON THE 22/06Z TAF CYCLE.
VFR CONDITIONS ARE EXPECTED TO PREVAIL TODAY. HOWEVER TEMPORARY MVFR
CONDITIONS WITH PARTIAL MOUNTAIN OBSCURATIONS AND REDUCED
VISIBILITIES ARE POSSIBLE NEAR AND WITHIN SHOWERS WITH LOCALLY
GUSTY WINDS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
ORZ029.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR ORZ029.
CA...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
CAZ084.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ084.
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ081.
PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 5 PM PDT THIS
AFTERNOON FOR PZZ350-356.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT THIS EVENING FOR
PZZ370-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ370.
$$
000
FXUS66 KMFR 220336
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
836 PM PDT TUE MAY 21 2013
.DISCUSSION...THE UPPER LOW IS NOW CENTERED JUST OFF THE NW OREGON
COAST AND COLD AIR CONTINUES TO POUR IN OVER OUR AREA. SNOW LEVELS
ARE DOWN TO AROUND 3500 FEET ALREADY AND WE ARE SEEING
ACCUMULATING SNOW ON MANY OF THE MOUNTAIN WEBCAMS. WE WILL
CONTINUE TO COOL THROUGH THE NIGHT WITH SNOW LEVELS BOTTOMING OUT
AROUND 2000 FEET TOMORROW MORNING. THE GOOD NEWS IS THAT SHOWERS
WILL LESSEN OVERNIGHT WHICH SHOULD KEEP ACCUMULATING SNOW CONFINED
TO THE MOUNTAINS AND NOT OF SUFFICIENT QUANTITY TO CAUSE MANY
PROBLEMS. NEVERTHELESS, ANYONE TRAVELING OVER THE MOUNTAINS AND
ACROSS THE EAST SIDE SHOULD BE PREPARED FOR SLICK, ICY ROADWAYS
AND OCCASIONAL REDUCTIONS TO VISIBILITY DUE TO SNOW.
OTHER CONCERNS INCLUDE THE POTENTIAL FOR FREEZING TEMPERATURES IN
AGRICULTURAL AREAS. FREEZING TEMPERATURES IN THE EAST SIDE VALLEYS
IS VIRTUALLY CERTAIN NOW AND WEST SIDE VALLEYS ARE ALSO STARTING
TO WORRY ME. DETERMINISTIC GUIDANCE SHOWS LOWS AROUND 35 IN
MEDFORD PROPER WHICH WOULD BRING IT CLOSE TO FREEZING IN THE
OUTLYING AREAS. CURRENT THINKING IS THAT CLOUD COVER WILL HOLD
TEMPERATURES UP, BUT IF WE GET MORE CLEARING THAN EXPECTED WITH
SUCH A COLD AIRMASS IN PLACE, IT COULD GET PRECARIOUSLY CLOSE TO
FREEZING. WILL BE EVALUATING THIS AS NEW GUIDANCE COMES IN, BUT
WILL STICK WITH THIS THINKING FOR NOW. SUFFICE IT TO SAY IT MAY
NOT BE A GOOD NIGHT FOR AREA VEGETABLE GARDENS, ESPECIALLY OUTSIDE
THE CITIES AND JUST ABOVE THE VALLEYS.
WINDS ARE DYING DOWN ACROSS THE EAST SIDE, SO WIND ADVISORIES HAVE
BEEN LOWERED. IT WILL BE BREEZY OVERNIGHT IN THE NORMALLY WINDIER
AREAS, BUT NOTHING TOO UNUSUAL. MAY DO SOME UPDATES TO CLEAN UP
THE GRIDS, BUT PROBABLY NO MAJOR CHANGES. -WRIGHT
&&
.AVIATION...A COLD FRONT HAS PASSED OVER THE AREA...BUT AREAS OF
GUSTY WINDS AND SHOWERS REMAIN. WINDS SHOULD WEAKEN THROUGH THE
EARLY EVENING. PRECIPITATION WILL CONTINUE TO RESIDE OVER THE
FORECAST AREA THROUGHOUT THE TAF PERIOD. VFR PREVAILS AT THIS
TIME...BUT SOME MVFR CONDITIONS HAVE BEEN REPORTED WITHIN AREAS OF
HEAVIER PRECIPITATION. THIS WILL LIKELY BECOME MORE COMMON DURING
THE OVERNIGHT HOURS. AS FREEZING LEVELS DROP TO 3000 FEET OR
BELOW...SHOWERS OVER HIGHER ELEVATIONS AND ACROSS THE EAST SIDE
WILL TRANSITION TO SNOW...AND VISIBILITIES THERE WILL SUFFER
ACCORDINGLY. MOUNTAIN OBSCURATION WILL OCCUR FREQUENTLY. -BPN
&&
.PREV DISCUSSION... /ISSUED 307 PM PDT TUE MAY 21 2013/
SHORT TERM...A COLD FRONT HAS MOVED INLAND AND EAST OF THE
CASCADES TODAY. BEHIND THIS FRONT A LARGE AND UNUSUALLY COLD UPPER
LOW WILL MOVE INTO PLACE TONIGHT AND PERSIST ON WEDNESDAY. THEN AN
UPPER LOW REMAINS OVER THE AREA THURSDAY INTO FRIDAY. HOWEVER
THE COLDEST AIR WILL SHIFT EAST AND THE AIR MASS WILL GRADUALLY
WARM.
SHOWERS HAVE MOVED INLAND ACROSS AREAS WEST OF THE CASCADES AND
EXPECT SHOWERS TO PERSIST TONIGHT AND WEDNESDAY AS THE UPPER LOW
REMAINS OVER THE AREA. TODAY AND THIS EVENING...VERY COLD AIR ALOFT
IS MOVING INTO NORTHWEST PORTIONS OF THE CWA BRINGING WEAK
INSTABILITY. THIS WILL ALLOW SOME HEAVIER SHOWERS WITH STRONG GUSTY
WINDS AND SMALL HAIL POSSIBLE. ALSO A SLIGHT CHANCE FOR THUNDERSTORMS
ARE POSSIBLE OVER COOS AND DOUGLAS COUNTY THROUGH THIS
EVENING...WHERE MODELS SHOW BEST INSTABILITY ASSOCIATED WITH THE
VERY COLD AIR ALOFT. WINDS ACROSS THE AREA WILL REMAIN GUSTY INTO
THIS EVENING WITH STRONGEST WINDS EXPECTED EAST OF THE CASCADES.
SNOW LEVELS ARE EXPECTED TO LOWER TO 3000 FEET WEST OF THE
CASCADES IN OREGON THIS EVENING THEN DOWN TO 2500 TO 2800 FEET
TONIGHT. SNOW LEVELS WILL RISE TO AROUND 3500 TO 4000 FEET DURING
THE DAY WEDNESDAY. WITH THE COLD AIR MASS AND CONTINUED
SHOWERS...SNOW IS EXPECTED FOR MOUNTAIN LOCATIONS THIS EVENING INTO
WEDNESDAY. SNOW AMOUNTS OF 3 TO 6 INCHES ARE POSSIBLE IN THE
SOUTHERN OREGON CASCADES. HOWEVER LIGHTER SNOW ACCUMULATIONS ARE
EXPECTED AT SISKIYOU SUMMIT. ALSO WARM GROUND TEMPERATURES MAY
ALLOW SNOW TO MELT QUICKLY ESPECIALLY BELOW 4000 FEET ELEVATION.
LOCALLY SNOW LEVELS MAY LOWER TO 2000 FEET AT TIMES TONIGHT. SO
LOWER PASSES SUCH AS SEXTON SUMMIT MAY SEE BRIEF PERIODS OF SNOW
SHOWERS OVERNIGHT INTO WEDNESDAY MORNING...HOWEVER EXPECT LITTLE
OR NO ACCUMULATION.
BY EARLY WEDNESDAY MORNING...UNUSUALLY COLD TEMPERATURES ARE
FORECAST ACROSS THE AREA. TEMPERATURES IN MANY WEST SIDE
VALLEYS...INCLUDING PORTIONS OF THE ROGUE AND ILLINOIS
VALLEYS...ARE EXPECTED TO LOWER INTO THE MID 30S AND TEMPERATURES
IN EAST SIDE AND NORTHERN CALIFORNIA VALLEYS ARE EXPECTED TO BE
AROUND FREEZING OR BELOW. MOSTLY CLOUDY CONDITIONS ARE EXPECTED WEST OF
THE CASCADES IN OREGON WHICH WILL MINIMIZE THE FROST POTENTIAL.
ON THURSDAY ANOTHER SHORTWAVE DISTURBANCE IS EXPECTED TO MOVE INTO
THE AREA AND BRING ANOTHER ROUND OF SHOWERS THURSDAY AND THURSDAY
NIGHT. SNOW LEVELS WILL BE HIGHER AROUND 4000 FT RISING TO 5000 TO
6000 FEET LATE IN THE DAY. ADDITIONALLY MODELS INDICATE WEAK
INSTABILITY EAST OF THE CASCADES...ESPECIALLY OVER LAKE
COUNTY...MAY BRING A SLIGHT CHANCE FOR THUNDERSTORMS THURSDAY
AFTERNOON AND EVENING.
THE UPPER LOW IS FORECAST TO REMAIN IN PLACE OVER THE REGION THURSDAY
NIGHT AND FRIDAY WITH ANOTHER SHORTWAVE ROTATING AROUND THE TROUGH
AND INTO THE AREA. THIS IS EXPECTED TO BRING ADDITIONAL SHOWERS
THURSDAY NIGHT INTO FRIDAY.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY NIGHT...
WITH THE CENTER OF THE UPPER LOW EXITING NORTHEAST OF OUR AREA BUT
STILL OVER THE PACIFIC NORTHWEST ON FRIDAY NIGHT, A WEAK SHORTWAVE
IN A WESTERLY FLOW ALOFT IS FORECAST TO CONTINUE A SLIGHT CHANCE TO
CHANCE OF LIGHT SHOWERS. THE PROBABILITY OF SHOWERS WILL BE HIGHEST
OVER THE HIGHER TERRAIN FROM THE NORTHERN PORTION OF THE SOUTHERN
OREGON CASCADES AND NORTHWARD.
THE 12Z GFS AND ECMWF AGREE ON A CONTINUED ACTIVE UPPER LEVEL
PATTERN AND SLIGHTLY WARMER TEMPERATURES FOR THE HOLIDAY WEEKEND.
BUT, THERE ARE STILL IMPORTANT DIFFERENCES IN THE TIMING AND
TRACK/POSITIONING OF THE FEATURES. I BROADENED THE MENTION OF A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ACROSS ALL OF
THE EAST SIDE SATURDAY AS THE NEXT UPPER TROUGH IS FORECAST TO MOVE
SOUTHEAST TO THE SOUTHERN OREGON COAST BY SATURDAY MORNING THEN EAST
ACROSS OUR AREA THROUGH THE EVENING. THE GFS IS STRONGER/WETTER AND
MORE UNSTABLE THAN THE ECMWF. DEPENDING ON WHICH WAY THE MODELS
TREND...IT IS FORSEEABLE FOR THE PROBABILITY OF RAIN FORECAST TO
CHANGE IN EITHER DIRECTION.
THE MODEL DIFFERENCES INCREASE ON SUNDAY AS COMPARED TO THE ECMWF,
THE GFS MAINTAINS A STRONGER VERSION OF THE TROUGH OVER OUR AREA BUT
IS WEAKER WITH AN UPSTREAM TROUGH OFFSHORE FROM VANCOUVER ISLAND.
DESPITE THE UNCERTAINTY IN STRENGTH, IT IS LIKELY THAT THE TROUGH
WILL STILL BE IN PLACE OVER OUR AREA. SO, A SLIGHT CHANCE TO CHANCE
OF SHOWERS WAS MAINTAINED IN THE FORECAST.
ADDITIONAL SLIGHT WARMING IS FORECAST FOR MEMORIAL DAY WITH THE
POTENTIAL FOR A COLD FRONT TO APPROACH THE COAST LATE IN THE DAY.
THE GFS SOLUTION IS A BIT STRONGER AND ABOUT 6 HOURS FASTER THAN THE
ECMWF, BUT THE PROBABILITY OF PRECIPITATION WILL INCREASE MONDAY
NIGHT...ESPECIALLY IN SOUTHWEST OREGON AND NORTHWARD.
MODEL DIFFERENCES ARE VERY LARGE BY TUESDAY WITH THE POSSIBILITY THAT
A FRONT WILL STILL BE LINGERING OVER THE EAST SIDE...TRANSITIONING
TO COOL SHOWERY POST FRONTAL AIR MASS, OR WEAK RIDGING COULD ARRIVE
IN BETWEEN SYSTEMS. COOL AND OCCASIONALLY WET WEATHER IS LIKELY TO
CONTINUE THROUGH NEXT WEEK. /DW
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR ORZ029.
CA...FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ084.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ081.
PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 5 PM PDT
WEDNESDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING FOR
PZZ376.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
PZZ370.
$$
000
FXUS66 KMFR 212209 CCA
AFDMFR
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MEDFORD OR
307 PM PDT TUE MAY 21 2013
.SHORT TERM...A COLD FRONT HAS MOVED INLAND AND EAST OF THE
CASCADES TODAY. BEHIND THIS FRONT A LARGE AND UNUSUALLY COLD UPPER
LOW WILL MOVE INTO PLACE TONIGHT AND PERSIST ON WEDNESDAY. THEN AN
UPPER LOW REMAINS OVER THE AREA THURSDAY INTO FRIDAY. HOWEVER
THE COLDEST AIR WILL SHIFT EAST AND THE AIR MASS WILL GRADUALLY
WARM.
SHOWERS HAVE MOVED INLAND ACROSS AREAS WEST OF THE CASCADES AND
EXPECT SHOWERS TO PERSIST TONIGHT AND WEDNESDAY AS THE UPPER LOW
REMAINS OVER THE AREA. TODAY AND THIS EVENING...VERY COLD AIR ALOFT
IS MOVING INTO NORTHWEST PORTIONS OF THE CWA BRINGING WEAK
INSTABILITY. THIS WILL ALLOW SOME HEAVIER SHOWERS WITH STRONG GUSTY
WINDS AND SMALL HAIL POSSIBLE. ALSO A SLIGHT CHANCE FOR THUNDERSTORMS
ARE POSSIBLE OVER COOS AND DOUGLAS COUNTY THROUGH THIS
EVENING...WHERE MODELS SHOW BEST INSTABILITY ASSOCIATED WITH THE
VERY COLD AIR ALOFT. WINDS ACROSS THE AREA WILL REMAIN GUSTY INTO
THIS EVENING WITH STRONGEST WINDS EXPECTED EAST OF THE CASCADES.
SNOW LEVELS ARE EXPECTED TO LOWER TO 3000 FEET WEST OF THE
CASCADES IN OREGON THIS EVENING THEN DOWN TO 2500 TO 2800 FEET
TONIGHT. SNOW LEVELS WILL RISE TO AROUND 3500 TO 4000 FEET DURING
THE DAY WEDNESDAY. WITH THE COLD AIR MASS AND CONTINUED
SHOWERS...SNOW IS EXPECTED FOR MOUNTAIN LOCATIONS THIS EVENING INTO
WEDNESDAY. SNOW AMOUNTS OF 3 TO 6 INCHES ARE POSSIBLE IN THE
SOUTHERN OREGON CASCADES. HOWEVER LIGHTER SNOW ACCUMULATIONS ARE
EXPECTED AT SISKIYOU SUMMIT. ALSO WARM GROUND TEMPERATURES MAY
ALLOW SNOW TO MELT QUICKLY ESPECIALLY BELOW 4000 FEET ELEVATION.
LOCALLY SNOW LEVELS MAY LOWER TO 2000 FEET AT TIMES TONIGHT. SO
LOWER PASSES SUCH AS SEXTON SUMMIT MAY SEE BRIEF PERIODS OF SNOW
SHOWERS OVERNIGHT INTO WEDNESDAY MORNING...HOWEVER EXPECT LITTLE
OR NO ACCUMULATION.
BY EARLY WEDNESDAY MORNING...UNUSUALLY COLD TEMPERATURES ARE
FORECAST ACROSS THE AREA. TEMPERATURES IN MANY WEST SIDE
VALLEYS...INCLUDING PORTIONS OF THE ROGUE AND ILLINOIS
VALLEYS...ARE EXPECTED TO LOWER INTO THE MID 30S AND TEMPERATURES
IN EAST SIDE AND NORTHERN CALIFORNIA VALLEYS ARE EXPECTED TO BE
AROUND FREEZING OR BELOW. MOSTLY CLOUDY CONDITIONS ARE EXPECTED WEST OF
THE CASCADES IN OREGON WHICH WILL MINIMIZE THE FROST POTENTIAL.
ON THURSDAY ANOTHER SHORTWAVE DISTURBANCE IS EXPECTED TO MOVE INTO
THE AREA AND BRING ANOTHER ROUND OF SHOWERS THURSDAY AND THURSDAY
NIGHT. SNOW LEVELS WILL BE HIGHER AROUND 4000 FT RISING TO 5000 TO
6000 FEET LATE IN THE DAY. ADDITIONALLY MODELS INDICATE WEAK
INSTABILITY EAST OF THE CASCADES...ESPECIALLY OVER LAKE
COUNTY...MAY BRING A SLIGHT CHANCE FOR THUNDERSTORMS THURSDAY
AFTERNOON AND EVENING.
THE UPPER LOW IS FORECAST TO REMAIN IN PLACE OVER THE REGION THURSDAY
NIGHT AND FRIDAY WITH ANOTHER SHORTWAVE ROTATING AROUND THE TROUGH
AND INTO THE AREA. THIS IS EXPECTED TO BRING ADDITIONAL SHOWERS
THURSDAY NIGHT INTO FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY NIGHT...
WITH THE CENTER OF THE UPPER LOW EXITING NORTHEAST OF OUR AREA BUT
STILL OVER THE PACIFIC NORTHWEST ON FRIDAY NIGHT, A WEAK SHORTWAVE
IN A WESTERLY FLOW ALOFT IS FORECAST TO CONTINUE A SLIGHT CHANCE TO
CHANCE OF LIGHT SHOWERS. THE PROBABILITY OF SHOWERS WILL BE HIGHEST
OVER THE HIGHER TERRAIN FROM THE NORTHERN PORTION OF THE SOUTHERN
OREGON CASCADES AND NORTHWARD.
THE 12Z GFS AND ECMWF AGREE ON A CONTINUED ACTIVE UPPER LEVEL
PATTERN AND SLIGHTLY WARMER TEMPERATURES FOR THE HOLIDAY WEEKEND.
BUT, THERE ARE STILL IMPORTANT DIFFERENCES IN THE TIMING AND
TRACK/POSITIONING OF THE FEATURES. I BROADENED THE MENTION OF A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ACROSS ALL OF
THE EAST SIDE SATURDAY AS THE NEXT UPPER TROUGH IS FORECAST TO MOVE
SOUTHEAST TO THE SOUTHERN OREGON COAST BY SATURDAY MORNING THEN EAST
ACROSS OUR AREA THROUGH THE EVENING. THE GFS IS STRONGER/WETTER AND
MORE UNSTABLE THAN THE ECMWF. DEPENDING ON WHICH WAY THE MODELS
TREND...IT IS FORSEEABLE FOR THE PROBABILITY OF RAIN FORECAST TO
CHANGE IN EITHER DIRECTION.
THE MODEL DIFFERENCES INCREASE ON SUNDAY AS COMPARED TO THE ECMWF,
THE GFS MAINTAINS A STRONGER VERSION OF THE TROUGH OVER OUR AREA BUT
IS WEAKER WITH AN UPSTREAM TROUGH OFFSHORE FROM VANCOUVER ISLAND.
DESPITE THE UNCERTAINTY IN STRENGTH, IT IS LIKELY THAT THE TROUGH
WILL STILL BE IN PLACE OVER OUR AREA. SO, A SLIGHT CHANCE TO CHANCE
OF SHOWERS WAS MAINTAINED IN THE FORECAST.
ADDITIONAL SLIGHT WARMING IS FORECAST FOR MEMORIAL DAY WITH THE
POTENTIAL FOR A COLD FRONT TO APPROACH THE COAST LATE IN THE DAY.
THE GFS SOLUTION IS A BIT STRONGER AND ABOUT 6 HOURS FASTER THAN THE
ECMWF, BUT THE PROBABILITY OF PRECIPITATION WILL INCREASE MONDAY
NIGHT...ESPECIALLY IN SOUTHWEST OREGON AND NORTHWARD.
MODEL DIFFERENCES ARE VERY LARGE BY TUESDAY WITH THE POSSIBILITY THAT
A FRONT WILL STILL BE LINGERING OVER THE EAST SIDE...TRANSITIONING
TO COOL SHOWERY POST FRONTAL AIR MASS, OR WEAK RIDGING COULD ARRIVE
IN BETWEEN SYSTEMS. COOL AND OCCASIONALLY WET WEATHER IS LIKELY TO
CONTINUE THROUGH NEXT WEEK. /DW
&&
.AVIATION...A COLD FRONT HAS REACHED THE EAST SIDE OF THE
CASCADES WITH WEST TO NORTHWEST WIND GUSTS OF 25 TO 40 KT...AREAS
OF RAIN AND SNOW...MVFR CEILINGS AND MOUNTAIN OBSCURATIONS.
BEHIND THE FRONT...NORTHWEST WINDS WILL REMAIN BREEZY THROUGH THIS
EVENING WITH WIND GUSTS TO 25 KT. SHOWERS AND SNOW SHOWERS...MAINLY
IN SOUTHWEST OREGON WILL REMAIN NUMEROUS INTO WEDNESDAY EVENING WITH
OCCASIONAL MOUNTAIN OBSCURATIONS AND MVFR CEILINGS. THERE IS ALSO A
SLIGHT CHANCE OF THUNDERSTORMS NEAR THE COAST NORTH OF CAPE BLANCO
THIS EVENING. THE FREEZING LEVEL IS NEAR 4500 FEET AND
WILL FALL TO AROUND 3000 FEET OVERNIGHT.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORZ030-031.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR ORZ029.
CA...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR CAZ085.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ084.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ081.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM
PDT THIS AFTERNOON FOR PZZ350-356.
HAZARDOUS SEAS WARNING UNTIL 5 PM PDT WEDNESDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING FOR
PZZ376.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
PZZ370.
$$
CC
000
FXUS66 KMFR 212157
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
257 PM PDT TUE MAY 21 2013
.SHORT TERM...A COLD FRONT HAS MOVED INLAND AND EAST OF THE
CASCADES TODAY. BEHIND THIS FRONT A LARGE AND UNUSUALLY COLD UPPER
LOW WILL MOVE INTO PLACE TONIGHT AND PERSIST ON WEDNESDAY. THEN AN
UPPER LOW REMAINS OVER THE AREA THURSDAY INTO FRIDAY. HOWEVER
THE COLDEST AIR WILL SHIFT EAST AND THE AIR MASS WILL GRADUALLY
WARM.
SHOWERS HAVE MOVED INLAND ACROSS AREAS WEST OF THE CASCADES AND
EXPECT SHOWERS TO PERSIST TONIGHT AND WEDNESDAY AS THE UPPER LOW
REMAINS OVER THE AREA. TODAY AND THIS EVENING...VERY COLD AIR ALOFT
IS MOVING INTO NORTHWEST PORTIONS OF THE CWA BRINGING WEAK
INSTABILITY. THIS WILL ALLOW SOME HEAVIER SHOWERS WITH STRONG GUSTY
WINDS AND SMALL HAIL POSSIBLE. ALSO A SLIGHT CHANCE FOR THUNDERSTORMS
ARE POSSIBLE OVER COOS AND DOUGLAS COUNTY THROUGH THIS
EVENING...WHERE MODELS SHOW BEST INSTABILITY ASSOCIATED WITH THE
VERY COLD AIR ALOFT. WINDS ACROSS THE AREA WILL REMAIN GUSTY INTO
THIS EVENING WITH STRONGEST WINDS EXPECTED EAST OF THE CASCADES.
SNOW LEVELS ARE EXPECTED TO LOWER TO 3000 FEET WEST OF THE
CASCADES IN OREGON THIS EVENING THEN DOWN TO 2500 TO 2800 FEET
TONIGHT. SNOW LEVELS WILL RISE TO AROUND 3500 TO 4000 FEET DURING
THE DAY WEDNESDAY. WITH THE COLD AIR MASS AND CONTINUED
SHOWERS...SNOW IS EXPECTED FOR MOUNTAIN LOCATIONS THIS EVENING INTO
WEDNESDAY. SNOW AMOUNTS OF 3 TO 6 INCHES ARE POSSIBLE IN THE
SOUTHERN OREGON CASCADES. HOWEVER LIGHTER SNOW ACCUMULATIONS ARE
EXPECTED AT SISKIYOU SUMMIT. ALSO WARM GROUND TEMPERATURES MAY
ALLOW SNOW TO MELT QUICKLY ESPECIALLY BELOW 4000 FEET ELEVATION.
LOCALLY SNOW LEVELS MAY LOWER TO 2000 FEET AT TIMES TONIGHT. SO
LOWER PASSES SUCH AS SEXTON SUMMIT MAY SEE BRIEF PERIODS OF SNOW
SHOWERS OVERNIGHT INTO WEDNESDAY MORNING...HOWEVER EXPECT LITTLE
OR NO ACCUMULATION.
BY EARLY WEDNESDAY MORNING...UNUSUALLY COLD TEMPERATURES ARE
FORECAST ACROSS THE AREA. TEMPERATURES IN MANY WEST SIDE
VALLEYS...INCLUDING PORTIONS OF THE ROGUE AND ILLINOIS
VALLEYS...ARE EXPECTED TO LOWER INTO THE MID 30S AND TEMPERATURES
IN EAST SIDE AND NORTHERN CALIFORNIA VALLEYS ARE EXPECTED TO BE
AROUND FREEZING OR BELOW. MOSTLY CLOUDY CONDITIONS ARE EXPECTED WEST OF
THE CASCADES IN OREGON WHICH WILL MINIMIZE THE FROST POTENTIAL.
ON THURSDAY ANOTHER SHORTWAVE DISTURBANCE IS EXPECTED TO MOVE INTO
THE AREA AND BRING ANOTHER ROUND OF SHOWERS THURSDAY AND THURSDAY
NIGHT. SNOW LEVELS WILL BE HIGHER AROUND 4000 FT RISING TO 5000 TO
6000 FEET LATE IN THE DAY. ADDITIONALLY MODELS INDICATE WEAK
INSTABILITY EAST OF THE CASCADES...ESPECIALLY OVER LAKE
COUNTY...MAY BRING A SLIGHT CHANCE FOR THUNDERSTORMS THURSDAY
AFTERNOON AND EVENING.
THE UPPER LOW IS FORECAST TO REMAIN IN PLACE OVER THE REGION THURSDAY
NIGHT AND FRIDAY WITH ANOTHER SHORTWAVE ROTATING AROUND THE TROUGH
AND INTO THE AREA. THIS IS EXPECTED TO BRING ADDITIONAL SHOWERS
THURSDAY NIGHT INTO FRIDAY. THEN...MODELS ARE IN GOOD AGREEMENT
SHOWING THE UPPER TROUGH SHIFTING EAST FRIDAY NIGHT AND THE CHANCE
FOR SHOWERS DECREASING.
&&
.AVIATION...A COLD FRONT HAS REACHED THE EAST SIDE OF THE
CASCADES WITH WEST TO NORTHWEST WIND GUSTS OF 25 TO 40 KT...AREAS
OF RAIN AND SNOW...MVFR CEILINGS AND MOUNTAIN OBSCURATIONS.
BEHIND THE FRONT...NORTHWEST WINDS WILL REMAIN BREEZY THROUGH THIS
EVENING WITH WIND GUSTS TO 25 KT. SHOWERS AND SNOW SHOWERS...MAINLY
IN SOUTHWEST OREGON WILL REMAIN NUMEROUS INTO WEDNESDAY EVENING WITH
OCCASIONAL MOUNTAIN OBSCURATIONS AND MVFR CEILINGS. THERE IS ALSO A
SLIGHT CHANCE OF THUNDERSTORMS NEAR THE COAST NORTH OF CAPE BLANCO
THIS EVENING. THE FREEZING LEVEL IS NEAR 4500 FEET AND
WILL FALL TO AROUND 3000 FEET OVERNIGHT.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORZ030-031.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR ORZ029.
CA...WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR CAZ085.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ084.
FREEZE WARNING FROM 2 AM TO 9 AM PDT WEDNESDAY FOR CAZ081.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ350-356.
HAZARDOUS SEAS WARNING UNTIL 5 PM PDT WEDNESDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT THIS EVENING FOR
PZZ376.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
PZZ370.
$$
CC
000
FXUS66 KMFR 211621
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
921 AM PDT TUE MAY 21 2013
.SHORT TERM...A LARGE AND UNUSUALLY COLD UPPER LOW IS MOVING INTO
THE REGION TODAY AND TONIGHT. THIS WILL BRING A COLD FRONT INLAND
TODAY AND TONIGHT FOLLOWED BY THE UPPER LOW REMAINING OVER THE
AREA ON WEDNESDAY AND THURSDAY.
THE FORECAST REMAINS ON TRACK WITH THIS SYSTEM BRINGING INCREASED
WINDS TO THE AREA TODAY...ESPECIALLY EAST OF THE CASCADES. LIGHT
TO MODERATE PRECIPITATION WILL MOVE INTO THE WEST SIDE TODAY AND
CONTINUE TONIGHT AND WEDNESDAY. WITH THE FRONTAL PASSAGE TODAY
EXPECT THE ATMOSPHERE TO BE UNSTABLE IN NORTHWEST PORTIONS OF THE
CWA INCLUDING DOUGLAS AND COOS COUNTY WITH A SLIGHT CHANCE FOR
THUNDERSTORMS. SOME SHOWERS TODAY MAY ALSO BRING SMALL HAIL.
SNOW LEVELS ARE EXPECTED TO LOWER TO 3500 FEET WEST OF THE
CASCADES IN OREGON THIS EVENING THEN DOWN TO 2500 TO 3000 FEET
OVERNIGHT. SNOW LEVELS WILL RISE TO AROUND 3500 FEET DURING THE
DAY WEDNESDAY. SNOW AMOUNTS OF 3 TO 7 INCHES ARE POSSIBLE IN THE
SOUTHERN OREGON CASCADES. HOWEVER LIGHTER SNOW ACCUMULATIONS ARE
EXPECTED AT SISKIYOU SUMMIT. ALSO WARM GROUND TEMPERATURES MAY
ALLOW SNOW TO MELT QUICKLY ESPECIALLY BELOW 4000 FEET ELEVATION.
LOWER PASSES SUCH AS SEXTON SUMMIT ARE EXPECTED TO RECEIVE LITTLE
IF ANY SNOW TONIGHT INTO WEDNESDAY.
ALSO BY EARLY WEDNESDAY MORNING...EXPECT UNUSUALLY COLD
TEMPERATURES OVER THE AREA WITH SOME WEST SIDE VALLEYS REACHING
THE LOWER TO MID 30S AND EAST SIDE AND NORTHERN CALIFORNIA VALLEYS
EXPECTED NEAR OR BELOW FREEZING. MOSTLY CLOUDY CONDITIONS ARE
EXPECTED WEST OF THE CASCADES IN OREGON AND WILL MINIMIZE THE
FROST POTENTIAL.
ON THURSDAY ANOTHER SHORTWAVE DISTURBANCE IS EXPECTED TO MOVE INTO
THE AREA AND BRING ANOTHER ROUND OF SHOWERS THURSDAY AND THURSDAY
NIGHT. SNOW LEVELS WILL BE HIGHER AROUND 4000 FT RISING TO 5000 TO
6000 FEET LATE IN THE DAY.
&&
.AVIATION...CLOUDS WILL SPREAD INLAND ACROSS THE WEST SIDE THIS
MORNING WITH A MIX OF VFR AND MVFR ALONG WITH HIGHER TERRAIN
OBSCURATIONS. MVFR WILL BE MOST PREVALENT AT THE COAST AND INTO
THE UMPQUA BASIN. RAIN AT THE COAST WILL SPREAD TO THE CASCADES
LATER THIS MORNING. VFR OVER THE EAST SIDE WILL GIVE WAY TO SOME
CLOUDS LATER THIS MORNING INTO THE AFTERNOON ALONG WITH SOME
SHOWERS, BUT CIGS SHOULD REMAIN MOSTLY VFR. GUSTY WINDS WILL
DEVELOP IN MANY AREAS THIS AFTERNOON WITH GUSTS OF 25-30 KT AT
KMFR AND 30-35 KT AT KLMT. FREEZING LEVELS WILL DROP ABRUPTLY
TODAY FROM NEAR 10000 FT MSL THIS MORNING TO AROUND 3000 FT MSL BY
WEDNESDAY MORNING. /FB
&&
.PREV DISCUSSION... /ISSUED 326 AM PDT TUE MAY 21 2013/
DISCUSSION...TODAY WILL BE MUCH COOLER...WETTER AND WINDIER COMPARED
TO YESTERDAY. TEMPERATURES TODAY WILL BE BETWEEN 15-20 DEGREES
COOLER ON AVERAGE. CURRENT WATER VAPOR IMAGE SHOWS A STRONG UPPER
LOW CENTERED JUST SOUTH OF THE ALASKA PANHANDLE. AT THE SAME TIME AN
UPPER TROF NEAR 128W AND 44N IS STARTING TO BECOME NEGATIVELY TILTED
WHICH IS IS A GOOD INDICATOR OF A DEVELOPING AND STRENGTHENING
SYSTEM. THE MAIN CONCERNS FOR TODAY WILL BE THE FOLLOWING. GUSTY
WINDS...ESPECIALLY ALONG AND EAST OF THE CASCADES...MODERATE TO
HEAVY PRECIPITATION ALONG THE COAST AND COAST RANGE WITH THE
POTENTIAL FOR SMALL HAIL AND SNOW LEVELS RAPIDLY FALLING DURING THE
DAY WITH ACCUMULATING SNOW POSSIBLE BY EVENING UP TOWARDS DIAMOND
AND CRATER LAKE.
SHOWERS WILL START OT MOVE INTO THE COAST AND COAST RANGE EARLY THIS
MORNING...THEN PUSH INLAND DURING THE DAY. AT THIS TIME EXPECTING
MOST OF THE MODERATE TO HEAVY SHOWERS TO BE MAINLY CONFINED TO ALONG
AND WEST OF THE CASCADES AND IN OREGON. DON`T THINK MUCH WILL MAKE
IT INTO NORTHERN CAL...SO DECIDED TO ADJUST POPS AND QPF AMOUNTS
DOWN. COLD AIR MASS ALOFT WILL MOVE INTO THE NORTHWEST PART OF THE
AREA LATE THIS AFTERNOON WITH 500MB TEMPS BETWEEN -25 AND -30 C
MOVING OVERHEAD. COULD NOT RULE OUT ISOLATED THUNDERSTORMS IN
NORTHERN COOS AND DOUGLAS COUNTIES LATE THIS AFTERNOON INTO EARLY
EVENING.
WINDS ARE GOING TO BE ANOTHER CONCERN...ESPECIALLY ALONG AND EAST OF
THE CASCADES. MODELS SHOW 700MB WINDS BETWEEN 30-40 KTS AND 500MB
WINDS BETWEEN 50-60 KTS. I MENTION 500MB WINDS BECAUSE THERE IS THE
POTENTIAL SOME OF THE STRONGER WINDS ABOVE 700 MB COULD MIX DOWN
NEAR THE SURFACE WITH SOME LOCATIONS REACHING WIND ADVISORY
CRITERIA. THEREFORE HAVE DECIDED TO ISSUE A WIND ADVISORY. THERE IS
A CHANCE FOR GUSTY WINDS TO DEVELOP IN THE ROGUE VALLEY. FOR NOW
HAVE OPTED NOT TO ISSUE AN ADVISORY...BUT THE DAY SHIFT MAY NEED TO
REEVALUATE.
SNOW LEVELS START OUT BETWEEN 6500 AND 7500 FEET...BUT WILL QUICKLY
FALL TO AROUND 4000 FEET BY LATE AFTERNOON. THEREFORE ANYONE
TRAVELING TO OR FROM DIAMOND LAKE OR CRATER LAKE NEED TO BE ON THE
WATCH FOR RAPIDLY CHANGING CONDITIONS FROM MODERATE TO HEAVY RAIN TO
RAIN/WET SNOW MIX TO MODERATE TO HEAVY WET SNOW. GIVEN THE GROUND
AND ROAD TEMPERATURES ARE WARM...THE SNOW WILL MELT AT FIRST...BUT I
EXPECT IT TO ACCUMULATE EARLY THIS EVENING THROUGH TONIGHT. SNOW
LEVELS TONIGHT WILL LOWER TO AROUND 2800 FEET...BUT GIVEN THE
CONVECTIVE NATURE OF THE SHOWERS COULD TEMPORALLY DROP DOWN TO
AROUND 2000 FEET.
THE UPPER LOW WILL MOVE OVERHEAD WEDNESDAY AND REMAIN THERE THROUGH
THURSDAY WITH PLENTY OF COLD AIR ALOFT RESULTING IN INSTABILITY
SHOWERS WITH GUSTY WINDS. SNOW LEVELS START OUT AROUND 2800 FEET
WEDNESDAY MORNING...THEN INCREASING TO 4000 FEET WEDNESDAY
AFTERNOON. MOST OF THE ACCUMULATING SNOW WEDNESDAY WILL BE IN THE
MORNING AND MOST LIKELY AROUND CRATER AND DIAMOND LAKE AREAS. THERE
IS A CHANCE FOR MINOR ACCUMULATIONS NEAR SISKIYOU SUMMIT AND LAKE OF
THE WOODS WEDNESDAY MORNING...THEN ROADS WILL BE WET FROM LATE
MORNING INTO THE AFTERNOON. THUNDERSTORM CHANCES ARE VERY LOW MAINLY
DUE TO LITTLE BREAKS IN THE CLOUD COVER RESULTING IN LESS
INSTABILITY.
THE UPPER LOW GRADUALLY WEAKENS FRIDAY THROUGH NEXT WEEKEND AND THE
AIR MASS IS NOT EXPECTED TO BE AS COLD. STILL THE CHANCE FOR SHOWERS
EXIST WITH TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY FROM NOON TODAY TO 8 PM PDT THIS EVENING FOR
ORZ030-031.
CA...WIND ADVISORY FROM NOON TODAY TO 8 PM PDT THIS EVENING FOR
CAZ085.
FREEZE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
CAZ081.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 PM PDT THIS EVENING FOR
PZZ350-356.
HAZARDOUS SEAS WARNING UNTIL 8 PM PDT WEDNESDAY FOR PZZ350-356.
GALE WARNING UNTIL NOON PDT TODAY FOR PZZ370-376.
HAZARDOUS SEAS WARNING UNTIL 8 PM PDT WEDNESDAY FOR PZZ370-376.
$$
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