Hazardous Seas Warning 31, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
838 PM PDT WED JUN 22 2011

.DISCUSSION...UPPER SHORTWAVE CONTINUES TO APPROACH THE COAST THIS
EVENING. AFTER ANOTHER FAIRLY HOT DAY AREA-WIDE (EXCEPT COAST),
THE GRADIENT IS NOW FIRMLY ONSHORE ACROSS THE WEST SIDE. THE
THERMAL TROUGH IS NOW OVER CENTRAL OREGON AND WILL CONTINUE TO THE
EAST TONIGHT AS THE TROUGH AXIS MOVES ONSHORE. THIS WILL MEAN A
GOOD MARINE PUSH INTO THE AREAS WEST OF THE CASCADES FOLLOWED BY A
MUCH COOLER DAY TOMORROW. ISOLDATED THUNDERSTORMS DID DEVELOP ON
THE EAST SIDE THIS EVENING BUT THE MAJORITY OF THE ACTIVITY WAS
OVER NE OREGON. THE ACTIVITY HAS DIED OUT OVER MY FORECAST AREA AS
THE SUN SETS AND BOUNDARY LAYER COOLS. DID A QUICK UPDATE TO
REMOVE ALL POPS AND WEATHER FROM THE EAST SIDE THIS EVENING.
AFOREMENTIONED MARINE LAYER WILL PRODUCE STRATUS WHICH SHOULD REACH
ALL THE WAY TO THE CASCADES BY MORNING. NOT EXPECTING ANY PRECIP
TONIGHT EXCEPT FOR PATCHY DRIZZLE OVER THE NORTH COAST. GIVEN
TIME OF YEAR IT SHOULD BE QUICK TO BURN OFF OVER MUCH OF THE WEST
SIDE AND RETREAT TO THE COAST BY LATE MORNING. NEVERTHLESS, AFTER
A COUPLE OF WELL ABOVE NORMAL DAYS TEMP-WISE, THIS PUSH IS STRONG
ENOUGH TO LEAVE US WITH BELOW NORMAL TEMPS TOMORROW AND INTO FRI,
BEFORE WE WARM BACK UP OVER THE WEEKEND. -WRIGHT

&&

.AVIATION...ISOLD TS IS OVER ACROSS CENTRAL OREGON FOR THIS
EVENING. UPR TROUGH AND ONSHORE LL GRADIENT WILL DRIVE MARINE
LAYER AND STRATUS WITH MVFR CIGS TO THE CASCADES TONIGHT. COULD
EVEN SEE AREAS OF IFR CIGS WILL POSSIBLE MVFR VIS IN -DZ/BR OVER
THE NORTH COAST BY TOMORROW AM. STRATUS SHOULD RETREAT TO THE
COAST BY 23/18Z WITH VFR CONDS ALL AREAS AWAY FROM COAST THROUGH
TOMORROW AFTERNOON. -WRIGHT

&&

.PREV DISCUSSION... /ISSUED 234 PM PDT WED JUN 22 2011/

SHORT TERM...WEDNESDAY NIGHT THROUGH SATURDAY NIGHT...ALL MODELS
IN VERY GOOD AGREEMENT THROUGH THE SHORT TERM. WEAK INSTABILITY
OVER KLAMATH...LAKE...SISKIYOU AND MODOC COUNTIES HAS SOME CUMULUS
CLOUDS FORMING A ISOLATED SHOWERS AND THUNDERSHOWERS. THE CLOSED
LOW CURRENTLY OVER THE NORTHEAST PACIFIC HAS SEVERAL SHORT WAVES
ROTATING AROUND IT. THE 500 MB HEIGHTS HAVE FALLEN SOME TODAY WITH
A SHORT WAVE APPROACHING THE COAST. THE SYSTEM HAS VERY WEAK
DYNAMICS AND WILL MAINLY DEEPEN THE MARINE LAYER ALONG THE COAST
AND INTO THE UMPQUA BASIN THURSDAY. IT SHOULD ALSO BE DEEP ENOUGH
TO SQUEEZE OUT SOME DRIZZLE NORTH OF CAPE BLANCO. THE NEXT WAVE IS
ON FRIDAY BUT IT IS EVEN WEAKER THAN THE FIRST SO IT WILL ONLY
KEEP TEMPERATURES MODERATED AND BRING A FEW CLOUDS.

OVERNIGHT LOW TEMPERATURES WILL BE RATHER COOL EAST OF THE
CASCADES. NORTHERN KLAMATH AND NORTHEAST LAKE COUNTIES WILL HAVE
FROST FRIDAY MORNING. TEMPERATURES WILL AGAIN BE CHILLY SATURDAY
MORNING BUT WILL MODERATE A BIT FOR PATCHY FROST.

LONG TERM...SUNDAY THROUGH WEDNESDAY...WE'VE TRENDED THE LONG RANGE
FORECAST A LITTLE WARMER AND DRIER. LATEST GFS AND EC SOLUTIONS ARE
IN FAVOR OF A PERIOD OF UNEVENTFUL ZONAL FLOW SUNDAY TRANSITIONING
INTO RIDGING MONDAY AS AN UPPER TROUGH DIGS OFFSHORE. THIS WILL
PLACE THE REGION IN A WARMING REGIME AS SOUTH FLOW DEVELOPS ALOFT.
WE'VE NUDGED HIGH TEMPERATURES TOWARD THE MEX GUIDANCE HERE. ON
TUESDAY...THE UPPER TROUGH IS FORECAST TO APPROACH 130W TUESDAY WITH
A POSSIBLE CUTOFF LOW CENTER SOUTH OF 40N. DUE TO MODEL SPREAD
CONFIDENCE IS LOW BUT IT LOOKS LIKE THE TROUGH MIGHT TRY TO SWING
INLAND BY WEDNESDAY. THUS...WITH THE GFS INDICATING A SWATH OF
INSTABILITY ACROSS THE CASCADES TUESDAY...WE'VE MENTIONED A SLIGHT
CHANCE FOR THUNDERSTORMS FOR AFTERNOON AND EVENING. THE WEDNESDAY
FORECAST IS SIMILAR BUT BROADENS THE AREAL COVERAGE AND BIT AND
SPREADS THE MENTIONS A BIT FURTHER EAST. STAVISH

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

CA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM PDT FRIDAY FOR
     PZZ356.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT FRIDAY
     FOR PZZ356.
     GALE WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY EVENING FOR
     PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 PM PDT THURSDAY FOR
     PZZ376.
     HAZARDOUS SEAS WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY
     EVENING FOR PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM PDT THURSDAY
     FOR PZZ376.