Gale Watch 6, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
1246 PM PST MON JAN 18 2016

.AVIATION...FOR THE 18/18Z TAF CYCLE...FOG AND STRATUS WILL
GRADUALLY DISSIPATE THIS AFTERNOON WITH ALL TERMINALS BECOMING
VFR. THE NEXT FRONT IS ALREADY APPROACHING THE COAST AND WILL
SPREAD RAIN WITH MVFR CIGS/VIS INLAND ACROSS THE WEST SIDE
OVERNIGHT. THE FRONT SHOULD HELP TO LIMIT FOG DEVELOPMENT TONIGHT,
BUT SOME FOG IS STILL POSSIBLE INLAND FROM THE COAST. SOUTH WINDS
WILL INCREASE ACROSS THE EAST SIDE AS THE FRONT MOVES INLAND, AND
THESE WINDS SHOULD PREVENT FOG FORMATION OVER THERE TONIGHT.
-WRIGHT

&&

.PREV DISCUSSION... /ISSUED 855 AM PST MON JAN 18 2016/

DISCUSSION...MADE A FEW ADJUSTMENTS TO THE FORECAST THIS MORNING.
A LOOK AT WEB CAMS SUGGEST THE DENSE FOG IS LIMITED OT THE UMPQUA
BASIN AND IN PORTIONS OF NORTHERN CAL. ELSEWHERE WEST OF THE
CASCADES WE HAVE LOW CLOUDS AND PACHY FOG. WE'LL KEEP THE DENSE
FOG ADVISORY GOING, BUT ONLY FOR THE UMPQUA BASIN AND PORTIONS OF
NORTHERN CAL. ALSO REMOVED PATCHY FREEZING FOG EAST OF THE
CASCADES WITH SEVERAL WEB CAMS SHOWING MOSTLY CLEAR SKIES. THE
MODELS ARE IN GOOD AGREEMENT WITH THE TIMING OF THE NEXT FRONT
WHICH IS EXPECTED TO REACH THE COAST LATE THIS AFTERNOON. SOME
LIGHTNING HAVE BEEN OBSERVED ALONG THIS FRONT WHICH IS STILL
OFFSHORE AND SEE NO REASON THAT WE WON'T HAVE AT LEAST ISOLATED
THUNDERSTORMS AS THE FRONT MOVES TOWARDS THE COAST, SO WE'LL KEEP
THEM IN THE FORECAST.

OUR NEXT ATTENTION WILL BE TONIGHT THROUGH TUESDAY. THE 12Z NAM IS
IN AND IT SHOWS THE LOW TRACKING EAST TO NORTHEAST INTO THE
CALIFIRNIA/OREGON BORDER WHICH IS SIMILAR TO THE 0Z EC SOLUTION.
THE 12Z CANADAIN IS SIMILAR TO THE NAM. TYPICALLY WHEN SURFACE LOW
DEVELOP (ESPECIALLY WHEN THEY DEEPEN RAPIDLY) THEY TEND TO CURVE
NORTHEAST WHICH IS WHAT THE GFS SOLUTION SHOWS. HOWEVER THE ONE
THING THE THAT IS SIMILAR IS NONE OF THE MODELS SHOW RAPIDLY
DEEPENING WHICH COULD BE PART OF THE REASON WHY A FEW OF THE
SOLUTIONS TRACK THE SURFACE LOW NEAR THE OREGON/CALIFORNIA BORDER.
THIS LEADS TO LOWER CONFIDENCE WITH THE FORECAST WIND. -PETRUCELLI

MARINE...UPDATED 340 AM PST MONDAY 18 JAN 2016...THIS MORNING
HIGH WEST SWELL WILL BRING CONTINUED STEEP SEAS. A FRONT WILL
BRING STRONG SOUTH WINDS TODAY WITH WINDS REACHING GALE FORCE AND
SEAS BECOMING VERY STEEP ACROSS MUCH OF THE AREA. WINDS AND SEAS
WILL LOWER BRIEFLY TONIGHT. A STRONG SURFACE LOW WILL MOVE NORTH
ALONG THE COAST LATE TONIGHT THROUGH TUESDAY AFTERNOON AND BRING
THE POTENTIAL FOR GALE TO STORM FORCE WINDS AS WELL AS VERY STEEP
WIND DRIVEN SEAS. STORM FORCE WINDS ARE EXPECTED MAINLY BEYOND
10NM FROM SHORE AND FROM BANDON SOUTHWARD TO CAPE FERRELO ON
TUESDAY WITH GALES ELSEWHERE. MODELS SHOW VARIABILITY ON THE TRACK
AND EXACT STRENGTH OF THIS LOW AND THE FORECAST MAY CHANGE WITH
RESPECT TO WHERE THE STRONGEST WINDS AND HIGHEST SEAS WILL OCCUR
ON TUESDAY. ADDITIONAL STRONG FRONTS ARE EXPECTED FROM WEDNESDAY
INTO THE WEEKEND. /CC

PREV DISCUSSION... /ISSUED 512 AM PST MON JAN 18 2016/

DISCUSSION...
IN THE WAKE OF YESTERDAY'S MAJOR FRONTAL SYSTEM THE COQUILLE RIVER
CONTINUES TO RISE ABOVE ACTION STAGE ON THE SOUTH FORK AT MYRTLE
POINT AND AT COQUILLE. THE ROGUE RIVER AT AGNESS IS CURRENTLY
CRESTING AT A FLOOD STAGE OF 20 FEET. THE SCOTT AND KLAMATH ARE
STILL RISING, AS WELL, WITH THE SCOTT CURRENTLY AT ACTION STAGE.
OTHER WATERWAYS ARE ELEVATED, WITH MOST RECEDING. AT THIS POINT IT
APPEARS THE ROGUE AT AGNESS AND THE COQUILLE AT COQUILLE WILL BE
THE TWO FORECAST POINTS TO REACH FLOOD STAGE FROM THIS EVENT.
LITTLE BUTTE CREEK DID ALSO FLOOD ON SUNDAY.

RAINFALL AMOUNTS FROM YESTERDAY'S STORM WERE PRETTY CLOSE TO
FORECAST, BUT THE CONTRIBUTIONS FROM SNOW MELT AND POSSIBLY FROM
WET SOIL CONDITIONS FROM OUR ABOVE AVERAGE PRECIPITATION OVER THE
LAST MONTH AND A HALF RESULTED IN A GREATER HYDROLOGIC RESPONSE.
OF NOTE, THE SNOW THAT FELL IN THE MOUNTAINS YESTERDAY AT 6-8KFT
ELEVATIONS WAS ON THE ORDER OF 5 TO 10 INCHES WITH AN IMPRESSIVELY
WET 5:1 SNOW TO WATER RATIO...MEANING THAT 10 INCHES OF SNOW HAD
2 INCHES OF WATER IN IT!

THIS MORNING AREAS OF DENSE FOG HAS FORMED IN SOME WEST SIDE
VALLEYS. THIS FOG HAS BEEN SPORADIC IN MANY AREAS DUE TO SOME WIND
AND INSTABILITY REMAINING. INCREASING STABILITY THIS MORNING IS
LIKELY TO CAUSE AREAS OF DENSE FOG FOR MANY WEST SIDE VALLEY AREAS
AWAY FROM THE COAST. EXPECT IMPROVEMENT IN VISIBILITIES LATER THIS
MORNING.

THIS AFTERNOON AND EVENING THE NEXT FRONT WILL PUSH INTO THE
COASTAL WATERS AND ONTO THE WEST SIDE, BUT IS LIKELY TO GET HUNG
UP ALONG OR NEAR THE COAST RANGE. TONIGHT THROUGH TUESDAY MODELS
HAVE COME INTO BETTER AGREEMENT ON A VIGOROUS AREA OF LOW PRESSURE
TRACKING APPROXIMATELY THROUGH THE COASTAL WATERS AND ONTO THE
COOS COUNTY COAST. MODEL SPREAD IS STILL FAIRLY LARGE ON THE TRACK
AND STRENGTH OF THIS LOW, BUT THE NAM12 SEEMS TO BE ABOUT
CONSENSUS AND RESOLVES THE VALLEY-MOUNTAIN DETAILS BETTER THAN THE
OTHER MODELS, SO MOSTLY RELIED ON THIS. THERE WILL BE SOME HAZARDS
TO BE AWARE OF WITH THIS LOW SHOULD IT DEVELOP LIKE THE
NAM12/CONSENSUS INDICATES. THESE ARE STRONG WINDS ALONG THE COAST,
IN THE MOUNTAINS, SHASTA VALLEY, AND PORTIONS OF THE EAST SIDE ON
TUESDAY. A PERIOD OF MODERATE TO HEAVY SNOW IS ALSO POSSIBLE IN
THE MOUNTAINS. WATCHES HAVE BEEN ISSUED FOR THESE POTENTIAL HAZARDS.

ADDITIONALLY VERY NOTABLE FOR TUESDAY IS THAT THE GFS AND THE
NAM12 INDICATE COLD AIR OVERTAKING A LOWER LEVEL WARM SECTOR
LINGERING ALONG AND NEAR THE COAST WHICH COULD GIVE RISE TO
SLANTWISE CONVECTION AND THUNDERSTORMS, SIMILAR TO WHAT OCCURRED
ON SATURDAY MORNING WHEN WIND DAMAGE OCCURRED IN THE COOS BAY TO
MYRTLE POINT AREAS. THESE THUNDERSTORMS AND/OR ASSOCIATED STRONG
POST FRONTAL WINDS COULD PUSH ONTO THE COAST AND INTO THE INTERIOR
WEST SIDE. THIS SORT OF DEVELOPMENT IS KNOWN AS A SECONDARY COLD
FRONT OR BENT BACK OCCLUSION. IT IS A LOW PROBABILITY OF
OCCURRING, BUT HIGH IMPACT TYPE OF EVENT. SINCE THE MODELS HAVE
BEEN HINTING AT IT FOR A COUPLE OF DAYS NOW, IT SEEMS LIKELY TO
OCCUR, HOWEVER, THOUGH PINNING DOWN THE LOCATION AND SEVERITY IS
PROBLEMATIC UNTIL IT STARTS TO DEVELOP. AT THIS POINT THE MOST
LIKELY AREAS TO BE AFFECTED ARE WEST SIDE AREAS IN OREGON BETWEEN
FROM BROOKINGS AND GRANTS PASS NORTHWARD TO COOS BAY AND ROSEBURG.

CURRENT HEADLINES DEPICT MAINLY THE HIGHER LEVEL THREATS FROM
THIS LOW. SUSPECT WE'LL PROBABLY NEED SOME ADVISORIES ELSEWHERE.

AFTER THE TUESDAY STORM MODELS INDICATE A WARMER PERIOD THROUGH
THURSDAY, TURNING COOLER FRIDAY INTO SATURDAY WITH FRONTAL SYSTEMS
THURSDAY THROUGH SATURDAY. ANY LULL IN STORM ACTIVITY APPEARS AS
IF IT WILL BE BRIEF, AS ENSEMBLES AND CLIMATE MODELS KEEP THE
STORM TRACK LOCKED IN PLACE OVER AND NEAR OUR FORECAST AREA PRETTY
MUCH THROUGH THE NEXT 4+ WEEKS. BTL

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     ORZ030-031.
     HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
     FOR ORZ021-022.
     HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     ORZ027-028.

CA...HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     CAZ085.
     HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     CAZ083.
     WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
     FOR CAZ082.
     HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
     FOR CAZ081.

PACIFIC COASTAL WATERS...GALE WATCH FROM LATE TONIGHT THROUGH TUESDAY
     AFTERNOON FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR
     PZZ350-356-376.
     GALE WARNING UNTIL 10 PM PST THIS EVENING FOR
     PZZ350-356-370-376.
     STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON FOR
     PZZ370-376.