Hazardous Seas Warning 41, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
246 PM PDT SUN JUL 6 2014

.DISCUSSION...CLEAR SKIES PREVAIL TODAY...WITH THE EXCEPTION OF SOME LOW CLOUDS
AND FOG LURKING AROUND OFF THE FAR SOUTHERN OREGON COAST. ASIDE FROM
MARINE LAYER CLOUDS PUSHING INTO THE COAST OVERNIGHT...CLEAR SKIES
WILL CONTINUE THROUGH TOMORROW. CURRENTLY...A STRONG TROUGH IS
DIGGING INTO THE CENTRAL CONUS...AND THIS IS CAUSING A BROAD RIDGE
OVER THE FOUR CORNERS REGION TO BEGIN RETROGRADING TOWARDS THE WEST
COAST. VERY WARM AIR WILL SET IN OVER THE FORECAST AREA AS A
RESULT...BUT THE RIDGE WILL ALSO PROVIDE A SOUTHERLY FLOW THAT WILL
PULL MONSOONAL MOISTURE NORTH TOWARDS NORTHERN CALIFORNIA AND
SOUTHERN OREGON. THUS...THE MAIN FORECAST CORNERS DURING THE TERM
WILL BE HOT TEMPERATURES THROUGH WEDNESDAY...AND THE CHANCES FOR
THUNDERSTORMS OVER NORTHERN CALIFORNIA...AND THE CASCADES AND EAST
SIDE OF OREGON THROUGH MIDWEEK. MODELS ARE GOOD GENERAL AGREEMENT
THROUGH THIS TIME...THEREFORE LENDING TO INCREASING CONFIDENCE IN
THE SHORT TERM. THERE IS MUCH MORE UNCERTAINTY IN THE EXTENDED
TERM...AS MODEL SOLUTIONS HAVE BEEN INCONSISTENT FROM RUN TO RUN.

WITH RIDGING OVERHEAD...THE THERMAL TROUGH OVER CENTRAL CALIFORNIA
IS EXPECTED TO INTENSIFY AND SPREAD NORTH. THE EC AND THE GFS ARE
PRODUCING 850MB TEMPERATURES OF 24 DEGREES C OR HIGHER OVER THE
REGION BOTH MONDAY AND TUESDAY. WITH GOOD MIXING LIKELY...AND THE
BEHAVIOR OF THE THERMAL PROFILE OF THE ROGUE...SHASTA...AND SCOTT
VALLEYS...IT SEEMS THAT TEMPERATURES WILL MAKE A GOOD RUN INTO THE
LOW TRIPLE DIGITS BOTH DAYS. THE THERMAL TROUGH WILL ALSO RESULT IN
OFFSHORE FLOW...WHICH SHOULD KEEP LOW TEMPERATURES ELEVATED
OVERNIGHT. THIS SCENARIO COULD PUT STRESS ON SENSITIVE
GROUPS...ESPECIALLY THOSE WORKING OUTSIDE OR THOSE THAT DO NOT HAVE
AIR CONDITIONING. HAVE OPTED TO ISSUE A HEAT ADVISORY TO COVER THE
BULK OF THE VALLEYS IN SISKIYOU...JACKSON...AND JOSEPHINE COUNTIES.
THE APPLEGATE...KLAMATH...AND ILLINOIS VALLEYS SHOULD EXPERIENCE
BETTER COOLING MONDAY NIGHT INTO TUESDAY MORNING...SO HAVE LEFT THEM
OUT OF THE ADVISORY AREA. TEMPERATURES SHOULD COOL SLIGHTLY DURING
THE LATTER HALF OF THE WEEK...BUT HOT TEMPERATURES ARE LIKELY TO
RETURN BY NEXT WEEKEND.

MONSOONAL MOISTURE WILL BEGIN PUSHING INTO THE AREA FORM THE SOUTH
MONDAY EVENING. HOWEVER...VERY WARM TEMPERATURES AND VERY DRY AIR
WILL LIMIT THE EXTENT TO WHICH THE MOISTURE CAN INFILTRATE AT FIRST.
SOME AREAS OF INSTABILITY MAY DEVELOP MONDAY EVENING HOWEVER...MOSTLY
CONCENTRATED OVER THE HIGHER TERRAIN OF SISKIYOU COUNTY. THROUGH THE
NIGHT AND INTO TUESDAY...THE MOISTURE...AND INSTABILITY...WILL
SPREAD OVER THE REST OF NORTHERN CALIFORNIA AND PORTIONS OF SOUTHERN
OREGON. WARM MID LEVELS AND LITTLE UPPER LEVEL SUPPORT SHOULD KILL
ANY SUBSTANTIAL CONVECTIVE DEVELOPMENT WEST OF THE OREGON
CASCADES...BUT THE EAST SIDE AND THE CASCADES THEMSELVES SHOULD BE
ABLE TO OVERCOME CAPPING WITH THE HELP OF A SHORTWAVE OVERHEAD. HAVE
BUMPED THUNDERSTORMS UP TO CHANCE FOR THESE AREAS...WITH INITIATION
LIKELY OVER HIGHER TERRAIN IN THE AFTERNOON...AND STORMS THEN MOVING
TO THE NORTHEAST THROUGH THE EVENING. WITH AMPLE MONSOONAL MOISTURE
IN THE AREA...STORMS SHOULD PRODUCE RAIN AT THE GROUND...ALTHOUGH
INITIALLY SOME CELLS COULD BE DRY. THUNDERSTORMS CHANCES REMAIN IN
THE AREA THROUGH EARLY TUESDAY NIGHT.

A TROUGH WILL APPROACH THE PACIFIC NORTHWEST LATE TUESDAY...AND
SHOULD SKIRT TO THE NORTH WEDNESDAY. THIS WILL PUSH THE MOISTURE AND
INSTABILITY  TO THE EAST. HOWEVER...ENOUGH INSTABILITY SHOULD REMAIN
IN THE AREA WEDNESDAY AFTERNOON AND EVENING TO PERHAPS KICK OFF SOME
MORE THUNDER OVER THE HIGHER TERRAIN OF LAKE...MODOC...AND EASTERN
KLAMATH COUNTIES.

THROUGH THE LAST HALF OF THE FORECAST PERIOD...MODELS SOLUTIONS ARE
PRODUCING A TROUGH OR CLOSED LOW...DEPENDING ON THE MODEL AND THE
RUN...OFFSHORE OF CALIFORNIA. THE RESULT WILL BE A SHIFT IN THE
RIDGE AXIS...THEN EXPECTED TO STRETCH FROM THE SOUTHERN ROCKIES INTO
THE PACIFIC NORTHWEST. THE RESULTING MIDLEVEL FLOW WILL TURN TO THE
SOUTH. TEMPERATURES WILL WARM ONCE AGAIN TOWARDS TRIPLE DIGITS...BUT
THE SOUTHERLY COMPONENT COULD ALSO ACT TO PROVIDE ANOTHER SOURCE OF
MOISTURE. MODEL SOLUTIONS ARE ALSO RESOLVING SOME SMALL IMPULSES
WITHIN THE FLOW THAT COULD ALLOW THE ATMOSPHERE TO TAP THE RESULTING
INSTABILITY. DESPITE A HIGH DEGREE OF UNCERTAINTY...HAVE INTRODUCED
A SLIGHT CHANCE OF THUNDERSTORMS TO PORTIONS OF THE CASCADES AND
EAST SIDE EACH AFTERNOON AND EVENING THROUGH THE REMAINDER OF THE
FORECAST PERIOD. -BPN

&&

.AVIATION...BASED ON THE 06/18Z TAFS...
ALONG THE COAST AND INTO THE COASTAL VALLEYS EXPECT WIDESPREAD MVFR
CIGS TO RETURN FROM CAPE BLANCO NORTH WITH IFR CIGS SOUTH OF CAPE
BLANCO AROUND 04Z OR LATER TONIGHT, MAINLY FROM CAPE BLANCO NORTH
AND FROM BROOKINGS SOUTH. OTHERWISE VFR CONDITIONS FOR THE REMAINDER
OF THE FORECAST AREA. -FB

&&

.MARINE...UPDATED SUNDAY 6 JULY 245 AM PDT...
OFFSHORE HIGH PRESSURE WILL STRENGTHEN THROUGH THIS EVENING WHILE
A THERMAL TROUGH BUILDS ALONG THE COAST. THIS WILL RESULT IN GUSTY
NORTH WINDS AND STEEP SEAS SOUTH OF CAPE BLANCO. A DISSIPATING
FRONT MOVES INTO THE WATERS TONIGHT BRINGING AREAS OF LOW STRATUS.
THEN A STRONGER THERMAL TROUGH WILL DEVELOP MONDAY THROUGH
WEDNESDAY...BUILDING TO GALES AND VERY STEEP SEAS BY MONDAY
AFTERNOON. STRONG NORTH WINDS AND STEEP TO VERY STEEP SEAS WILL
CONTINUE THROUGH LATE IN THE WEEK.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
     EVENING FOR ORZ617-623>625.
     HEAT ADVISORY FROM NOON MONDAY TO 8 PM PDT TUESDAY FOR
     ORZ024-026.

CA...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
     EVENING FOR CAZ284-285.
     HEAT ADVISORY FROM NOON MONDAY TO 8 PM PDT TUESDAY FOR
     CAZ080-081.
     FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
     EVENING FOR CAZ280-281.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM
     THIS EVENING TO 3 PM PDT THURSDAY FOR PZZ350-356-370.
     HAZARDOUS SEAS WARNING FROM 5 AM MONDAY TO 3 PM PDT THURSDAY FOR
     PZZ350-356-370-376.
     GALE WARNING FROM 8 AM MONDAY TO 11 AM PDT THURSDAY FOR
     PZZ356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 PM THIS EVENING
     TO 3 PM PDT THURSDAY FOR PZZ350-356-370.
     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO 11 AM
     PDT THURSDAY FOR PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 PM THIS EVENING
     TO 5 AM PDT MONDAY FOR PZZ376.

BPN/FJB/SBN