Hazardous Seas Warning 39, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
922 AM PDT FRI AUG 14 2015

.DISCUSSION...THE FORECAST WAS UPDATED TO ISSUE A RED FLAG WARNING
FOR EASTERN MODOC COUNTY EXTENDING NORTHEASTWARD ACROSS SOUTHEAST
LAKE COUNTY FOR GUSTY WINDS AND LOW HUMIDITIES THIS AFTERNOON AND
EVENING. ELSEWHERE IN OUR AREA TODAY...ESPECIALLY FROM THE
CASCADES EASTWARD...CONDITIONS WILL NOT BE SO EXTREME AS TO REACH
RED FLAG CRITERIS. BUT, WINDS WILL BE STRONGER THAN NORMAL AND
HUMIDITIES LOWER THAN NORMAL. THIS IS DESPITE COOLING FROM A LOW
PRESSURE TROUGH. THE CENTER OF THE LOW HAS REACHED THE OREGON
COAST AND WILL CONTINUE TO TRACK NORTH-NORTHEAST INTO WASHINGTON
THIS AFTERNOON. IT MAY PRODUCE SPRINKLES OR LIGHT SHOWERS FROM THE
UMPQUA DIVIDE NORTHWARD AND THERE IS A SLIGHT CHANCE OF A
THUNDERSTORM THROUGH THIS AFTERNOON...FROM EASTERN DOUGLAS COUNTY
INTO FAR NORTHERN KLAMATH COUNTY. IN FACT, EARLIER THIS MORNING
THIS DISTURBANCE ALREADY PRODUCED A FEW STRIKES OF LIGHTNING IN
THE COASTAL ZONES.

THE TROUGH WILL ALSO BRING A PUSH OF MARINE AIR TONIGHT WITH LOW
CLOUDS EXPECTED FROM THE COAST THIS EVENING SPREADING INTO THE
UMPQUA VALLEY LATE TONIGHT. THESE LOW CLOUDS WILL GRADUALLY DISSIPATE
BACK TO THE COAST DURING SATURDAY MORNING. A WARMING AND DRYING
TREND WILL BEGIN ON SATURDAY WITH THE OUTLOOK FOR A STABLE AIR
MASS BUT HIGHER THAN NORMAL TEMPERATURES DURING THE NEXT WEEK.

&&

.AVIATION...FOR THE 14/12Z TAF CYCLE...EXPECT WILDFIRE SMOKE TO
RESULT IN OCCASIONAL REDUCTION IN VISIBILITY LOCALLY IN WESTERN
SISKIYOU COUNTY AND THE WEST SIDE. AT THE COAST, MVFR AND IFR CIGS
WILL BE THE PREDOMINATE CONDITION, BUT THERE IS A CHANCE THAT CIGS
WILL INCREASE TO MVFR AND AND POSSIBLY VFR AS CONDITIONS BECOME
MARGINALLY UNSTABLE THIS MORNING. MVFR CIGS MAY ALSO AFFECT THE
UMPQUA BASIN INCLUDING KRBG BEFORE DAYBREAK, THEN VFR CONDITIONS
WILL RETURN AFTER 18Z. ELSEWHERE VFR CONDITIONS WILL CONTINUE FOR THE
NEXT 24 HOURS. GUSTY WINDS ARE POSSIBLE IN THE AFTERNOON EAST OF THE
CASCADES. -PETRUCELLI

&&

.MARINE...UPDATED 300 AM PDT FRIDAY 14 AUGUST 2015...LIGHT WINDS AND
LOW SEAS WILL CONTINUE THROUGH THIS AFTERNOON. LOW PRESSURE ALOFT
WILL MOVE OVER THE WATERS THIS MORNING AND COULD BRING ISOLATED
SHOWERS AND THUNDERSTORMS THIS MORNING. A THERMAL TROUGH WILL
DEVELOP ALONG THE COAST FRIDAY NIGHT AND STRENGTHEN THIS WEEKEND.
NORTH WINDS WILL INCREASE WITH GALES AND STEEP HAZARDOUS SEAS LIKELY
SATURDAY AFTERNOON THROUGH SUNDAY NIGHT FOR THE OUTER WATERS SOUTH
OF CAPE BLANCO. MODEL BOUNDARY LAYER WINDS ARE INDICATED TO BE 40-
45KT...A GOOD PROXY FOR GALE FORCE SURFACE WIND SPEEDS. THEREFORE,
CONFIDENCE IS HIGH AND GALE/HAZARDOUS SEAS WATCHES HAVE BEEN ISSUED.
THE REST OF THE AREA WILL LIKELY HAVE WIND/SEA CONDITIONS THAT ARE
HAZARDOUS TO SMALL CRAFT. EARLY NEXT WEEK, MODERATE TO STRONG NORTH
WINDS AND CHOPPY SEAS MAY PERSIST OVER THE WATERS. -PETRUCELLI

&&

.FIRE WEATHER...UPDATED 830 AM PDT FRIDAY 14 AUGUST 2015...GUIDANCE
THIS MORNING STRONGLY SUGGESTS THAT SOME OF THE MORE TROUBLESOME
LOCATIONS IN NORTHEASTERN CALIFORNIA AND SOUTH CENTRAL OREGON WILL
REACH CRITERIA FOR RED FLAG WARNINGS THIS AFTERNOON AND EARLY THIS
EVENING. THIS WAS THE CASE YESTERDAY AS WELL, AND GIVEN HOW THE AREA
BEHAVED THEN, HAVE DECIDED TO ISSUE THE RED FLAG WARNING FOR AREAS
OF MODOC AND LAKE COUNTIES AGAIN TODAY. CONDITIONS SHOULD NOT LAST
AS LONG INTO THE EVENING AS YESTERDAY, AS THE LOW WILL PUSH EAST AND
THE AREA OF STRONGER WINDS WILL AS WELL.

MEANWHILE, WILL BE WATCHING THE THERMAL TROUGH AND OFFSHORE FLOW
EVENT FOR POSSIBLE FIRE WEATHER CONCERNS THIS WEEKEND, AND THE
PASSAGE OF A DRY COLD FRONT EARLY NEXT WEEK. -BPN

&&

.PREV DISCUSSION... /ISSUED 355 AM PDT FRI AUG 14 2015/

DISCUSSION...A FAIRLY SIGNIFICANT CHANGE IN THE WEATHER IS UPON
THE REGION AS A DEEP UPPER TROUGH LOCATED OFF THE SOUTH OREGON
COAST MOVES INTO THE PACIFIC NORTHWEST TODAY THROUGH SATURDAY. THE
PRIMARY CHANGES THAT WILL BE NOTICED ARE COOLER TEMPERATURES TODAY
AREA-WIDE AND INCREASED CLOUD COVER OVER THE WEST SIDE. AN AREA
OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS HAS BEEN IMPACTING
THE COAST RANGE AND NEARSHORE WATERS THROUGH THE NIGHT AND THIS
THREAT AREA WILL BE EXPANDING AND MOVING INLAND THIS MORNING. WE
FEEL GOOD WITH THE PREVIOUS SHIFT'S IDEA OF 20-50 PERCENT CHANCES
THROUGH THE DAYLIGHT HOURS FOR PRECIPITATION MAINLY OVER THE WEST
SIDE AND PRIMARILY ACROSS THE COOS AND UMPQUA AREAS. MOST RAINFALL
SHOULD BE LIGHT AND SPOTTY, BUT LOCAL AMOUNTS OF A TENTH OF AN
INCH LOOK POSSIBLE. WOULD BE SURPRISED TO SEE ANYTHING MORE THAN
THAT.

THE CLOSED LOW CENTER LOOKS ABOUT 5700M OFF CAPE BLANCO EARLY
TODAY AND IS ADVERTISED TO TRACK NORTH BY NORTHEAST AS IT OPENS
OVER WESTERN OREGON INTO WASHINGTON THROUGH MID DAY. A 35-65KT
SOUTHERLY JET BETWEEN 700-500MB WILL ON THE ADVANCE OF THIS WAVE
AND SHOULD ALLOW FOR CONSIDERABLE GUSTINESS IN THE AFTERNOON EAST
OF THE CASCADES. HIGHER TERRAIN INCLUDING THE SUMMER LAKE AREA AND
WARNERS WILL FEEL THIS THE MOST. FOR THE WEST SIDE, THE ONSHORE
PUSH OF MARINE AIR WILL BE FELT WITH NORTHWEST WINDS ALSO BECOMING
LOCALLY GUSTY BY AFTERNOON...MAINLY FROM MEDFORD TO AROUND
ASHLAND.

THE BROAD AREA OF SMOKE OVER THE WEST SIDE WILL BE SENT FROM WEST
TO EAST THOUGH THE DAY WITH THE MARINE PUSH. WITH FIRES TO THE
WEST AND SOUTH RECENTLY SMOKING UP THE COAST REGION, THIS MAY
PRODUCE ANOTHER INCREASING SMOKY AFTERNOON FOR INLAND AREAS UP TO
AND INCLUDING THE CASCADES DESPITE A FRESH SOURCE OF AIR COMING
IN OFF THE OCEAN. SOME AREAS SHHOULD WILL SEE RELIEF.

TONIGHT THROUGH SATURDAY AND THROUGH THE WEEKEND THE TROUGH MOVES
EAST AND HIGH PRESSURE REBUILDS WITH A THERMAL TROUGH STRENGHTNING
ALONG THE COAST. THIS MEANS THE LOW LEVEL WINDS WILL BECOME MORE
NORTH TO EAST AND THIS SHOULD PRODUCE SOME CONCERNS FOR THE
SOUTHWEST OREGON FIRES IN OFFSHORE FLOW.

MONDAY THROUGH TUESDAY HAS BEEN A LITTLE INCONSISTENT LATELY BUT
THE MOST RECENT RUNS OF THE EURO AND GFS NOW SHOW AT LEAST SOME
CONSISTENCY AS A DRY SHORTWAVE MOVES FROM THE BC COAST EARLY
MONDAY ACROSS WASHINGTON TO IDAHO MONDAY NIGHT. THIS TRANSITION
LOOKS PROMISING FOR A BRIEF SLIGHT COOL-DOWN WITH INCREASED WINDS
ACROSS SOME AREAS AND POTENTIAL INCREASING OFFSHORE FLOW INTO
EARLY TUESDAY. CONFIDENCE IS LOW IN THE TIMING OF THESE DETAILS
HOWEVER. THE MEX AND ECE NUMBERS ALSO POINT TO SOME POSSIBLE 100
DEGREE READINGS AT SOME POINT MID TO LATE WEEK FOR SW ORE. STAVISH

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 8 PM PDT THIS
     EVENING FOR ORZ625.

CA...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 8 PM PDT THIS
     EVENING FOR CAZ285.

PACIFIC COASTAL WATERS...GALE WATCH FROM SATURDAY AFTERNOON THROUGH
     LATE SUNDAY NIGHT FOR PZZ376.
     HAZARDOUS SEAS WATCH FROM SATURDAY AFTERNOON THROUGH LATE SUNDAY
     NIGHT FOR PZZ376.

DW/BPN