Hazardous Seas Warning 40, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
239 PM PDT SAT SEP 24 2011

.DISCUSSION...NO BIG CHANGES WERE MADE TO THE FORECAST TODAY.
MODELS CONTINUE TO ADVERTISE A COLD FRONT AFFECTING THE PACIFIC
NORTHWEST LATE TONIGHT INTO TOMORROW. CURRENT SATELLITE IMAGERY
SHOWS AN OCCLUDED LOW PRESSURE SYSTEM NEAR 42N 134W. THE PRESSURE
GRADIENT IS TIGHTENING AHEAD OF THE LOW...WITH GUSTY SOUTH WINDS
AFFECTING THE USUAL SUSPECTS...SHASTA VALLEY AND HIGHER TERRAIN OF
THE EAST SIDE. I HAVE RAMPED UP THE WINDS IN THE FORECAST SOME FOR
THE SHASTA VALLEY AS 700MB FLOW OF 40KT WILL MAINTAIN GUSTY
CONDITIONS INTO THE EARLY EVENING. ADDITIONALLY...SOME CUMULUS ARE
DEVELOPING OVER MODOC COUNTY AND THE CASCADES. STRONG SHEAR IN
COMBINATION WITH MARGINAL INSTABILITY WILL LIMIT VERTICAL
DEVELOPMENT OF THESE CLOUDS...BUT A FEW THUNDERSTORMS ARE STILL
POSSIBLE OVER MODOC COUNTY.

IN TERMS OF THE PRECIPITATION FORECAST...I HAVE INCREASED POPS SOME
AND MOVED THEM AHEAD IN TIME BASED ON MODELS TRENDING TOWARDS AN
EARLIER ARRIVAL OF THE FRONT. WHILE MOST OF THE AREA WILL NOT SEE
COPIOUS AMOUNTS OF PRECIPITATION...THE SUNDAY RAIN WILL REPRESENT
THE FIRST WIDESPREAD RAINFALL IN MONTHS. UP TO AN INCH OF RAIN IS
EXPECTED ALONG THE SOUTHWEST OREGON COAST...WITH NEARLY A QUARTER
INCH POSSIBLE OVER WESTERN SISKIYOU COUNTY AND INLAND AREAS FROM
THE CASCADES WESTWARD. GIVEN SUBSTANTIAL DRYING SOUTHERLY FLOW
AHEAD OF THE FRONT THE ROGUE VALLEY SHOULD RECEIVE LESS THAN A
TENTH OF AN INCH. LASTLY...THE EAST SIDE WILL STAY MAINLY
DRY...WITH LESS THAN A TENTH OF AN INCH THERE AS WELL.

COOLER TEMPERATURES IS THE THIRD MAIN EFFECT FROM THIS FRONT. YOU
WILL NO DOUBT FEEL THE CHANGE IN AIR MASS TOMORROW...WITH
TEMPERATURES DROPPING ABOUT 20 DEGREES F FROM TODAY. THIS COMES ON
THE HEELS OF FRIDAYS RECORD HEAT FOR KLAMATH FALLS AND MOUNT
SHASTA.  HIGH TEMPERATURES TOMORROW WILL BE THE COOLEST IN MORE THAN
TWO MONTHS.

HAVE OPTED TO LEAVE OUT FOG FOR THE UMPQUA BASIN SUNDAY NIGHT BASED
ON EXTENSIVE CLOUD COVER ALOFT...BUT FOG SEASON IS JUST AROUND THE
CORNER AND FUTURE SHIFTS MAY WANT TO CONSIDER THAT GIVEN POSSIBLE
WET GROUND AND STABLE CONDITIONS. A WARM FRONT WILL SKIRT THE
FORECAST AREA ON MONDAY...WITH MORE RAIN EXPECTED GENERALLY ALONG
AND NORTH OF A LINE FROM CAPE BLANCO TO CRATER LAKE.

A WARMING TREND WILL BEGIN ON TUESDAY AND LAST THROUGH THURSDAY WITH
MOSTLY DRY CONDITIONS EXPECTED DURING THIS PERIOD. AFTER THURSDAY
MODELS DISAGREE SOME ON THE PATTERN. GFS ENSEMBLE MEMBERS
GENERALLY FAVOR MOSTLY FLAT UPPER LEVEL FLOW OVER THE PACIFIC
NORTHWEST...RESULTING IN NEAR OR ABOVE NORMAL TEMPERATURES AND DRY
WEATHER. THE ECMWF SUGGESTS A MORE MERIDIONAL PATTERN WITH A
TROUGH OFFSHORE AND PERHAPS SOME AFTERNOON SHOWERS OVER THE AREA.
HAVE OPTED TO BLEND THE TWO SOLUTIONS SO HAVE SOME SLIGHT CHANCES
OF PRECIPITATION FRIDAY AND SATURDAY MAINLY OVER THE HIGHER
TERRAIN AND COASTLINE...AND TEMPERATURES ARE NEAR OR ABOVE NORMAL.

&&

.AVIATION...THE APPROACHING COLD FRONT IS LIFTING THE MARINE LAYER
AND DISRUPTING IT SOME...AND CEILINGS ARE GENERALLY MVFR ALONG THE
COAST EXCEPT FOR EXTREME SOUTHERN OREGON COAST NEAR BROOKINGS.
ADDITIONALLY GUSTY SOUTH WINDS AHEAD OF THE FRONT ARE IMPACTING THE
SHASTA VALLEY AND EAST SIDE SO TURBULENCE WILL BE INCREASING THIS
AFTERNOON OVER MOST OF THE EXPOSED TERRAIN. WINDS WILL GRADUALLY
DIMINISH A FEW HOURS AFTER SUNSET. VFR CONDITIONS EXIST EVERYWHERE
EXCEPT FOR THE COAST...AND WILL CONTINUE THAT WAY THROUGH TOMORROW
MORNING AT LEAST. CEILINGS AT THE COAST WILL THICKEN AND MAINLY BE
MVFR OVERNIGHT...WITH RAIN BEGINNING LATE TONIGHT. MOUNTAIN
OBSCURATION WILL IMPACT THE COAST RANGE AND WESTERN SISKIYOU COUNTY
LATE TONIGHT INTO EARLY SUNDAY MORNING.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ029>031.
     RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ027.

CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR
     CAZ081-083>085.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 8 PM THIS EVENING TO 5 PM
     PDT SUNDAY FOR PZZ350.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT SUNDAY
     FOR PZZ350-356.
     SMALL CRAFT ADVISORY FOR WINDS FROM 8 PM THIS EVENING TO 11 AM
     PDT SUNDAY FOR PZZ356.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT SUNDAY FOR
     PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
     FOR PZZ370-376.
     GALE WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
     PZZ370.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT SUNDAY FOR PZZ370.
     HAZARDOUS SEAS WATCH FROM MONDAY MORNING THROUGH MONDAY
     AFTERNOON FOR PZZ370.

SK/TW/MW/RS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MEDFORD OR
541 PM PDT SAT SEP 24 2011

CAZ281-284-285-ORZ624-625-250600-
CENTRAL SISKIYOU COUNTY INCLUDING SHASTA VALLEY-
SISKIYOU COUNTY FROM THE CASCADE MOUNTAINS EAST AND SOUTH TO MT
SHASTA-MODOC COUNTY EXCEPT FOR THE SURPRISE VALLEY-
KLAMATH BASIN AND THE FREMONT-WINEMA NATIONAL FOREST-
SOUTH CENTRAL OREGON DESERT INCLUDING THE BLM LAND IN EASTERN
LAKE AND WESTERN HARNEY COUNTIES-
541 PM PDT SAT SEP 24 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CA AND OR.

.DAY ONE...TONIGHT

A RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT TONIGHT FOR
STRONG WINDS WITH A LOW RELATIVE HUMIDITY. SEE THE FIRE WEATHER
MESSAGE FOR MORE SPECIFIC DETAILS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE PROBABILITY OF HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT NEEDED.