Hazardous Seas Warning 46, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
207 PM PDT SUN SEP 9 2012

.DISCUSSION...THE UPPER TROUGH CONTINUES TO DROP SOUTH THROUGH THE
GULF OF ALASKA AND ALONG THE B.C. COAST THIS AFTERNOON. THE
ASSOCIATED COLD FRONT IS ABOUT 400 MILES OFF OUR COAST AND WILL BE
ARRIVING HERE LATE TONIGHT. IN THE MEANTIME, ONSHORE FLOW HAS
ALREADY COOLED THINGS OFF APPRECIABLY THIS AFTERNOON WITH CURRENT
TEMPERATURES 10-20 DEGREES BELOW WHERE WE WERE YESTERDAY AT THIS
TIME OVER PORTIONS OF THE WEST SIDE. THE EAST SIDE IS ALSO COOLER
BUT BY ONLY 5-10 DEGREES OR SO. A STRATOCUMULUS FIELD HAS ERODED
FOR ALL BUT THE WESTERN UMPQUA AND NORTH COAST, WITH CLEAR SKIES
ELSEWHERE. NO RAIN IS EXPECTED TODAY, HOWEVER, ONSHORE GRADIENTS
CONTINUE TO TIGHTEN AND WILL THROUGH THE AFTERNOON AS PRESSURES
LOWER DUE TO HEATING EAST OF THE CASCADES. THIS WILL RESULT IN
GUSTY WEST TO SOUTHWEST WINDS OVER THE MOUNTAINS AND EAST SIDE,
MAINLY LATER THIS AFTERNOON.

AS THE MAIN UPPER TROUGH PROGRESSES INLAND ALONG THE US/CAN BORDER
TONIGHT, ITS TRAILING COLD FRONT WILL MOVE ONTO OUR COAST. IT MAY
PRODUCE A LITTLE LIGHT RAIN LATE TONIGHT INTO EARLY TOMORROW AS IT
MOVES INLAND. THE FRONT WILL WASH OUT AS IT MOVES INLAND TOMORROW
MORNING SO NOT EXPECTING ANY WIDESPREAD RAINFALL. WINDS WILL BE
BREEZY MOST AREAS TOMORROW AS HIGH PRESSURE BUILDS IN BEHIND THE
FRONT THROUGH THE DAY. THE INCREASING ONSHORE FLOW WILL RESULT IN
A MUCH STRONGER MARINE PUSH AND STRATUS WILL PROBABLY MAKE IT ALL
THE WAY TO THE CASCADES BY TOMORROW MORNING. CLOUDS ALONG WITH
WEAK COLD ADVECTION WILL MEAN EVEN COOLER TEMPERATURES FOR ALL
AREAS TOMORROW.

AS COOL AIR SETTLES IN, SKIES CLEAR, AND WINDS GO LIGHT TOMORROW
NIGHT INTO TUESDAY MORNING, WE WILL BE LOOKING AT A PRETTY CHILLY
NIGHT IN MANY AREAS. WE COULD SEE SOME READINGS IN THE UPPER 30S
TUESDAY MORNING ON THE WEST SIDE. ON THE EAST SIDE, THE FIRST
WIDESPREAD FREEZE IS POSSIBLE TUESDAY MORNING AND A FREEZE WATCH
HAS BEEN ISSUED TO HIGHLIGHT THE POTENTIAL.

THE UPPER TROUGH MOVES EAST AND TEMPERATURES MODERATE DURING THE
DAY TUESDAY. UPPER HIGH PRESSURE THEN BUILDS OVER THE PACNW
TUESDAY NIGHT AND REMAINS OVER THE AREA THROUGH THE BALANCE OF THE
WEEK. THIS WILL RESULT IN A RETURN TO SUNNY, DRY WEATHER WITH
ABOVE NORMAL TEMPERATURES FROM WEDNESDAY INTO NEXT WEEKEND. WE
WILL ALSO SEE OFFSHORE FLOW OVER THE COASTAL RANGES OF BOTH OREGON
AND NORTHERN CALIFORNIA, WHICH WILL CERTAINLY BE A CONCERN FOR
FIRE WEATHER BY MID WEEK. -WRIGHT

&&

.AVIATION...STRATOCUMULUS REMAINS OVER THE WESTERN UMPQUA AND
NORTH COAST THIS AFTERNOON, BUT CIGS ARE VFR AND WILL REMAIN SO
THROUGH THE AFTERNOON. AN UPPER TROUGH AND COLD FRONT WILL MOVE IN
LATER TONIGHT BRINGING A STRONG MARINE PUSH TO THE WEST SIDE.
ONSHORE FLOW WILL PROBABLY PRODUCE STRATUS WITH IFR CIGS RIGHT AT
THE COAST THIS EVENING AND THEN STRATUS WILL MOVE INLAND. MVFR
CIGS ARE EXPECTED TO SPREAD TO THE CASCADES (INCLUDING KMFR) BY
MORNING.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING FOR
     ORZ029>031.
     RED FLAG WARNING UNTIL 11 PM PDT MONDAY FOR ORZ030-031.
     RED FLAG WARNING UNTIL 11 PM PDT MONDAY FOR ORZ027.
     RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ029.

CA...FREEZE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING FOR
     CAZ082-084.
     RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR CAZ085.

PZ...GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE TUESDAY NIGHT FOR
     PZZ376.
     HAZARDOUS SEAS WATCH FROM MONDAY AFTERNOON THROUGH WEDNESDAY
     EVENING FOR PZZ376.