High Wind in California, December 12 to 13, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
959 PM PST SAT DEC 12 2015

.DISCUSSION...A MAJOR STORM WILL CONTINUE TO IMPACT SOUTHERN
OREGON AND NORTHERN CALIFORNIA THROUGH SUNDAY BUT JUST A VERY
MINOR ADJUSTMENT TO THE FORECAST THIS EVENING TO INCREASE RIDGE
TOP MAXIMUM TEMPERATURES ON SUNDAY. MAXIMUMS ON RIDGES AND IN SOME
VALLEYS ARE EXPECTED TO OCCUR IN THE MORNING WITH COOLING DURING
THE DAY. THE STRONGEST WINDS AND HEAVIEST PRECIPITATION WILL OCCUR
THROUGH SUNDAY MORNING WITH THE EXCEPTION THAT MODERATE
PRECIPITATION WILL LINGER INTO THE AFTERNOON IN MODOC COUNTY.
SNOW LEVELS ARE AT A PEAK AND WILL BE AROUND 5000 FEET OVERNIGHT
THEN A COLD FRONT WILL SEND SNOW LEVELS ABRUPTLY LOWER DURING
SUNDAY...DOWN TO AROUND 1500 TO 2000 FEET WHILE PRECIPITATION
TAPERS TO LIGHT INTENSITY. THERE MAY BE UP TO A COUPLE OF INCHES
OF SNOW AT THAT ELEVATION WITH HIGHER AMOUNTS ON WEST AND
NORTHWEST FACING SLOPES OF THE FOOTHILLS AND MOUNTAINS.
THE OTHER MAJOR SHORT TERM CONCERN IS RIVER FLOODING WITH THE
POTENTIAL FOR FLASH FLOODING AT BURN SCARS...PLEASE SEE THE
LATEST PRODUCTS /PDXFFAMFR AND PDXFLSMFR/ FOR DETAILS.

A COUPLE OF SHORTWAVE TROUGHS IN A COLD NORTHERLY POST-FRONTAL
AIR MASS WILL PROVIDE ADDITIONAL LIGHT SNOW TO LOW
ELEVATIONS...DOWN TO AROUND 1000 TO 1500 FEET SUNDAY NIGHT
THROUGH MONDAY. A FEW FLURRIES WILL LINGER MONDAY NIGHT THEN WEAK
HIGH PRESSURE WILL PROVIDE A BREAK IN THE WEATHER TUESDAY INTO
EARLY WEDNESDAY. THE 00Z GFS IS CONSISTENT THAT A MODERATELY
STRONG FRONT IN A WESTERLY FLOW IS EXPECTED TO BRING THE NEXT
BATCH OF PRECIPITATION LATE WEDNESDAY INTO THURSDAY. THERE IS A
HIGH AMOUNT OF UNCERTAINTY LATE IN THE WEEK WITH THE ECMWF WEAKER
THAN THE GFS WITH ANOTHER POTENTIALLY WET STORM FRIDAY INTO
SATURDAY.

&&

.AVIATION...FOR THE 13/00Z TAF CYCLE... MODERATE TO HEAVY RAIN WILL
CONTINUE ACROSS THE WEST SIDE TO THE CASCADES DURING THE AFTERNOON
AND ACROSS THE AREA BY THIS EVENING....WITH HEAVY SNOW AND
BLOWING SNOW ALREADY EAST OF THE CASCADES. THIS WILL PRODUCE MOUNTAIN
OBSCURATIONS WITH A MIX OF IFR AND MVFR CONDITIONS. THIS WILL
CONTINUE OVERNIGHT THROUGH AT LEAST TOMORROW MORNING. -SVEN

&&

.MARINE...UPDATED 830 PM PST SATURDAY 12 DEC 2015...STRONG
SOUTHERLY WINDS WILL VEER TO WESTERLY THIS EVENING THEN NORTHWEST
WINDS WILL INCREASE ON SUNDAY AND PERSIST INTO MONDAY NIGHT. VERY
STEEP SEAS ARE LIKELY THROUGH SUNDAY NIGHT. SEAS WILL LIKELY
REMAIN STEEP BUT GRADUALLY DIMINISH MONDAY THROUGH TUESDAY.
ANOTHER FRONT ARRIVES LATE WEDNESDAY INTO THURSDAY MORNING.
-SVEN/DW

&&

.PREV DISCUSSION... /ISSUED 442 PM PST SAT DEC 12 2015/

DISCUSSION...A MAJOR STORM WILL IMPACT MANY LOCATIONS THROUGH SUNDAY
NIGHT. THIS STORM WILL BRING SEVERAL WEATHER HAZARDS FOR MOST, IF
NOT THE ENTIRE FORECAST AREA. HEAVY RAIN WITH FLOODING. HEAVY SNOW
FOR THE MOUNTAINS AND HIGHER ELEVATIONS EAST OF THE CASCADES AND
NORTHERN CAL ARE GOING TO HAVE A MAJOR IMPACT THROUGH TONIGHT. A
STRONG WARM FRONT WILL PUSH WEST OF THE CASCADES LATE THIS
AFTERNOON, THEN EAST OF THE CASCADES THIS EVENING. THIS WILL RESULT
IN SNOW LEVELS BRIEFLY INCREASING BETWEEN 6000-7000 FEET FOR ABOUT 6
HOURS THIS EVENING, THEN THEY ARE EXPECTED TO LOWER AGAIN OVERNIGHT
TONIGHT. ALLOWING SNOW TO BRIEFLY CHANGE TO RAIN...EXCEPT AT THE
HIGHEST ELEVATIONS. MEANWHILE, AN UPPER TROUGH OFFSHORE WILL DIG AND
ENERGIZE A COLD FRONT THAT WILL MOVE ONSHORE BY SUNDAY MORNING. THIS
FRONT WILL HAVE A GOOD SUBTROPICAL MOISTURE FEED...AND WILL RESULT
IN A PERIOD OF INTENSE RAINFALL ALONG THE COAST AND INLAND...BUT
ESPECIALLY IN THE CURRY COAST RANGE WHERE OROGRAPHIC LIFT WILL
ENHANCE RAIN RATES. RAIN RATES EXCEEDING 0.50"/HR ARE LIKELY IN MANY
AREAS AND NUMEROUS FLOOD PRODUCTS ARE OUT AT FFAMFR. GUIDANCE
INDICATES THIS WILL BE A TOP 5 PERCENT 2-DAY RAIN EVENT FOR THE
AREA. THERE IS ALSO A FLASH FLOOD THREAT FOR BURN SCAR AREAS IN
PORTIONS OF DOUGLAS COUNTY WHERE THE STOUTS CREEK WILDFIRE OCCURRED
AS WELL AS IN WESTERN SISKIYOU COUNTY WHERE THE HAPPY CAMP AND JULY
WILDFIRES OCCURRED. MEANWHILE STRONG WINDS ALOFT ARE EXPECTED AHEAD
OF AND ALONG THE FRONT TONIGHT INTO SUNDAY MORNING AND ARE EXPECTED
TO PEAK OUT BETWEEN 70-80 KT EARLY SUNDAY MORNING. ALSO THE GRADIENT
BETWEEN RDD AND MFR WILL PEAK AT ABOUT 8-10 MB RESULTING IN STRONG
WINDS IN THE SHASTA VALLEY. ALSO STRONG WINDS ARE LIKELY NEAR SUMMER
LAKE. THE COMBINATION OF WIND AND SNOW COULD RESULT IN NEAR BLIZZARD
CONDITIONS UP AROUND CRATER LAKE NATIONAL PARK AND MOUNT ASHLAND.
THEREFORE IT'S STRONGLY RECOMMENDED YOU DO NOT TRAVEL IN THESE AREAS.

ON SUNDAY MUCH COLDER AIR WILL MOVE IN FROM NORTH TO SOUTH WEST OF
THE CASCADES. A LOOK AT MODEL SOUNDINGS SUGGEST THERE IS THE
POTENTIAL FOR CONDITIONS TO GO ISOTHERMAL AROUND 0C AROUND 15Z
(7AM PST) SUNDAY MORNING WHICH COULD RESULT IN RAIN CHANGING OVER
TO SNOW RATHER QUICKLY DURING THE MORNING HOURS SUNDAY RESULTING
IN SNOW ACCUMULATIONS ON THE PASSES ALONG I-5 BETWEEN GRANTS PASS
AND ROSEBURG, NOT TO MENTION SISKIYOU SUMMIT. SNOW LEVELS WILL
REMAIN LOW THROUGH MONDAY, AND ADDITIONAL DISTURBANCES WILL BRING
PRECIPITATION, ALL OF WHICH COULD FALL AS SNOW AT THE VALLEY
FLOORS ABOVE 1000 FEET. THIS WILL BE ESPECIALLY TRUE AT NIGHT AND
WHEN PRECIPITATION RATES ARE HIGH (HEAVY PRECIP CAN DRAG SNOW
LEVELS LOWER). BECAUSE OF THIS, HAVE ISSUED WINTER STORM WARNING
AND WINTER WEATHER ADVISORIES FOR WEST OF THE CASCADES FOR LATER
SUNDAY MORNING THROUGH MONDAY MORNING. NOT ALL VALLEY LOCATIONS
WILL NECESSARILY HAVE ANY SNOW ACCUMULATIONS, BUT ALL THOSE IN THE
ADVISORY COULD. SEE WSWMFR FOR MORE DETAILS.

COLD AIR ALOFT WILL MOVE IN SUNDAY NIGHT THROUGH MONDAY KEEPING POST-
FRONTAL SHOWERS GOING. THIS WILL ALSO RENEW A LIGHTNING/SMALL HAIL
THREAT OVER THE COASTAL WATERS AND ALONG THE IMMEDIATE COAST. SNOW
LEVELS WILL DROP DOWN NEAR THE VALLEY FLOORS WEST OF THE CASCADES BY
MONDAY MORNING AND WITH LEFTOVER SNOW SHOWERS IN THE AREA. MOST OF
THE PRECIPITATION DURING THE TIME IS EXPECTED TO BE CONFINED TO THE
CASCADES WEST. THE EASTSIDE AND NORTHERN CAL WILL SEE LIGHT QPF
AMOUNTS. -PETRUCELLI

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR
     ORZ029>031.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM PST MONDAY FOR
     ORZ030.
     WINTER STORM WARNING UNTIL 4 AM PST MONDAY FOR ORZ030.
     HIGH WIND WARNING UNTIL 10 AM PST SUNDAY FOR ORZ031.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM PST MONDAY FOR
     ORZ031.
     WINTER STORM WARNING UNTIL 4 AM PST MONDAY FOR ORZ031.
     FLOOD WATCH THROUGH SUNDAY EVENING FOR ORZ024-026.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ024.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ024.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ025.
     FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR ORZ023.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ025.
     FLOOD WATCH THROUGH SUNDAY EVENING FOR ORZ021-022.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 4 AM PST MONDAY FOR
     ORZ029.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ026.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ026.
     WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ023.
     WINTER STORM WARNING FROM 4 AM SUNDAY TO 10 AM PST MONDAY FOR
     ORZ023.
     WINTER STORM WARNING UNTIL 10 PM PST SUNDAY FOR ORZ027-028.
     WINTER STORM WARNING UNTIL 4 AM PST MONDAY FOR ORZ029.

CA...WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SUNDAY ABOVE 2000
     FEET FOR FOR CAZ080.
     WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SUNDAY FOR
     CAZ082.
     WINTER STORM WARNING UNTIL 10 PM PST SUNDAY FOR CAZ082.
     FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR CAZ080.
     WINTER STORM WARNING FROM 4 AM TO 10 PM PST SUNDAY ABOVE 3000
     FEET FOR FOR CAZ080.
     HIGH WIND WARNING UNTIL 7 AM PST SUNDAY FOR CAZ081.
     WINTER STORM WARNING FROM 4 AM TO 10 PM PST SUNDAY FOR CAZ081.
     WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR CAZ083.
     WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SUNDAY FOR
     CAZ084.
     WINTER STORM WARNING UNTIL 10 PM PST SUNDAY ABOVE 5000 FEET FOR
     FOR CAZ083.
     WINTER STORM WARNING FROM 4 AM TO 10 PM PST SUNDAY FOR CAZ085.
     WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SUNDAY FOR
     CAZ083.
     WINTER WEATHER ADVISORY FROM 10 AM TO 10 PM PST SUNDAY FOR
     CAZ085.

PACIFIC COASTAL WATERS...HAZARDOUS SEAS WARNING UNTIL 10 PM PST SUNDAY FOR
     PZZ350-356-370-376.

DW/MAP/SBN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
608 PM PST SAT DEC 12 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0607 PM     HEAVY RAIN       KERBY                   42.19N 123.65W
12/12/2015  M2.00 INCH       JOSEPHINE          OR   TRAINED SPOTTER

            24 HR ENDING 5 PM OBSERVER LOCATION MIDDLE
            OF KERBY BEHIND STONE FRONT TAVERN.

&&

SBN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MEDFORD OR
856 PM PST SAT DEC 12 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0645 PM     HEAVY SNOW       2 N KLAMATH FALLS       42.25N 121.78W
12/12/2015  M8.0 INCH        KLAMATH            OR   TRAINED SPOTTER

            OBSERVER LOCATION 1 MILE SOUTHWEST OF
            HOSPITAL.

&&

NWS MEDFORD OR
IRIS SYSTEM