FXUS66 KMFR 041726
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
926 AM PST FRI DEC 4 2009

.DISCUSSION...FOG CONTINUES TO IMPACT THE ROGUE AND ILLINOIS
VALLEY THIS MORNING AND LOW CLOUDS IN THE UMPQUA BASIN. THE 12Z
SOUNDING SHOWS THE MOISTURE LAYER ABOUT THE SAME AS YESTERDAY
MORNING. THEREFORE THE FOG AND LOW CLOUDS SHOULD BREAK UP EARLY
THIS AFTERNOON. THE WATER VAPOR IMAGE SHOWS AN UPPER LEVEL TROUGH
MOVING INTO WASHINGTON STATE AND WILL MAKE ITS WAY INTO OREGON
TONIGHT. THIS WILL ADVECT IN A DRIER AND COLDER AIRMASS DURING THE
OVERNIGHT HOURS WHICH SHOULD LIMIT THE AMOUNT OF LOW CLOUDS AND
FOG. DRY AND COLD CONDITIONS ARE EXPECTED SATURDAY AND SATURDAY
NIGHT. ANOTHER TROUGH WILL SWING INTO THE AREA SUNDAY AND COULD
BRING SCATTERED LIGHT SNOW SHOWERS SUNDAY..BUT NO ACCUMULATION IS
EXPECTED.  

&&

.AVIATION...LIFR CONDITIONS WILL PREVAIL IN THE ROGUE VALLEY
THROUGH THE MORNING. VISIBILITY SHOULD IMPROVE TO GREATER THAN A
MILE AFTER 21Z FOLLOWED BY THE CLOUD DECK BREAKING UP AFTER 22Z.
FOG AND LOW VISIBILITY WILL RETURN AFTER 3Z AND CONTINUE TONIGHT.
HOWEVER DRIER AIR WILL ALSO MOVE IN WHICH COULD LEAD TO IMPROVING
CONDITIONS OVERNIGHT TONIGHT. IFR WITH LOCAL LIFT CONDITIONS ARE
EXPECTED IN THE UMPQUA BASIN WITH VIS GREATER THAN 6 MILES...THEN
CLOUDS ARE EXPECTED TO BREAK UP AFTER 21Z WITH VFR CONDITIONS IN
THE AFTERNOON. ELSEWHERE SKIES WILL REMAIN CLEAR WITH A FEW HIGH
CLOUDS TODAY. 

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST SATURDAY FOR ORZ024-
     ORZ026-ORZ029-ORZ030-ORZ031.
     DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR ORZ024-
     ORZ026.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS 
     UNTIL 10 PM PST SATURDAY FOR PZZ350-PZZ356-PZZ370-PZZ376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 7 PM THIS EVENING TO 10 PM 
     PST SATURDAY FOR PZZ370-PZZ376.

$$

PETRUCELLI