Hazardous Seas Warning 28, NWS Medford, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
100 PM PDT FRI MAY 4 2012

.DISCUSSION...04/12Z NAM/GFS IN.

AN UPPER TROUGH IS NOW MOVING ONSHORE OVER THE PACIFIC
NORTHWEST...AND THIS IS SUPPORTING SHOWER ACTIVITY. THE STRONGEST
SHOWERS ARE IN A BAND STRETCHING ACROSS SOUTHEAST SISKIYOU AND
MODOC COUNTIES. A FEW LIGHTNING STRIKES HAVE OCCURRED OVER MODOC
COUNTY.

THE TROUGH WILL MOVE OUT TO THE EAST THIS EVENING AND THE SHOWERS
WILL END AS IT DOES SO. A BROAD UPPER LEVEL RIDGE WILL THEN MOVE
IN...KICKING OFF AN OFFSHORE LOW LEVEL FLOW EVENT.

IT WILL BE DRY SATURDAY THROUGH AT LEAST TUESDAY. INLAND HIGH
TEMPERATURES WILL WARM TO JUST BELOW NORMAL SATURDAY...ABOVE
NORMAL SUNDAY... AND THEN 8-15 DEGREES ABOVE NORMAL ON MONDAY.

EXTENDED DISCUSSION...TUESDAY THROUGH FRIDAY.

THE EC/GFS ENSEMBLES CLUSTER TIGHTLY INTO TUESDAY...THEN GRADUALLY
SPREAD THROUGH FRIDAY...AS ONE WOULD NORMALLY EXPECT. THE
OPERATIONAL SOLUTIONS CUT A PATH THROUGH THE MIDDLE OF THE
CLUSTERS FOR THE MOST PART. SO WILL GO WITH THE GENERAL SCENARIO
DEPICTED BY THE OPERATIONAL EC/GFS SOLUTIONS.

SHORT WAVES MOVING OVER THE RIDGE WILL SLOWLY BUT SURELY WEAR IT
DOWN...AND THE WEAKENED RIDGE WILL BREAK TO THE EAST TUESDAY. THE
UPSTREAM TROUGH IS WEAK THIS FAR SOUTH AND THE ASSOCIATED COLD
FRONT WILL MOVE ONSHORE TUESDAY EVENING. GIVEN THE WEAK UPPER
LEVEL SUPPORT FOR THIS FRONT AND THAT IT IS THE FIRST FRONT
ONSHORE AFTER AN OFFSHORE EVENT...WILL GO WITH A DRY FRONTAL
PASSAGE AT THIS TIME. THE FIRST FRONT IN AFTER AN OFFSHORE FLOW
EVENT IS USUALLY OVERDONE BY THE MODELS AND THE MODELS HAVE VERY
LITTLE PRECIPITATION WITH THIS SYSTEM TO BEGIN WITH.

AFTER THAT FRONT MOVES THROUGH...THE LOW LEVEL FLOW WILL TURN
OFFSHORE AGAIN FOR DRY WEATHER AND A WARMING TREND WEDNESDAY
THROUGH FRIDAY BACK TO ABOVE NORMAL VALUES INLAND.

AT SOME POINT A STRONG ENOUGH TROUGH WILL MOVE IN TO INDUCE
SOUTHERLY FLOW ALOFT OVER THE AREA AND THUNDERSTORMS WILL BECOME A
THREAT AGAIN. AT THIS POINT IT APPEARS THAT WILL NOT HAPPEN
THROUGH THE NEXT WEEK...BUT THIS WILL HAVE TO BE MONITORED.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH SATURDAY
...EXCEPT FOR LOCAL MVFR CIGS NEAR SHOWERS. THE LARGEST AREA OF
MVFR CIGS ARE ASSOCIATED WITH A BAND OF SHOWERS STRETCHING THROUGH
LAKE AND MODOC COUNTIES...AND THAT WILL MOVE OUT TO THE EAST LATER
TODAY.

&&

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

CA...NONE.

PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM SATURDAY TO 11 PM PDT
        SUNDAY FOR PZZ356.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM SATURDAY TO 11
        PM PDT SUNDAY FOR PZZ356.
     GALE WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR
        PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM TO 5 PM PDT SATURDAY
        FOR PZZ376.
     HAZARDOUS SEAS WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
        EVENING FOR PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM TO 5 PM PDT
        SATURDAY FOR PZZ376.

15/17/16