FXUS66 KMFR 010901
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
101 AM PST TUE DEC 1 2009

.DISCUSSION...01/00Z NAM/GFS IN.

NOT MUCH CHANGE IN THE OFFING FOR THE NEAR TERM FORECAST. AN
OFFSHORE UPPER RIDGE WILL PERSIST THROUGH THURSDAY. EXPECT MOSTLY
CLEAR SKIES INLAND EXCEPT FOR NIGHT THROUGH MORNING LOW CLOUDS AND
FOG IN THE WESTERN VALLEYS. AN AIR STAGNATION ADVISORY IS IN EFFECT
FOR JACKSON...JOSEPHINE...KLAMATH...AND LAKE COUNTIES THROUGH
FRIDAY MORNING.

FOR THE WEEKEND...THE DRY CONDITIONS WILL PREVAIL...BUT THE LATEST
GFS ADVERTISES AN ARCTIC OUTBREAK EAST OF THE CASCADES.  

THE MONDAY EVENING SHIFT COVERED THE END OF THE EXTENDED PERIOD
VERY WELL SO WILL JUST REPEAT IT HERE...THE HIGH PRESSURE RIDGE
IS LIKELY TO REMAIN OVER THE REGION THROUGH THE END OF THE WEEK.
THEREAFTER THE MODELS DIVERGE ON DETAILS...BUT AGREE THAT A
WESTERLY WIND BURST ASSOCIATED WITH A MADDEN JULIAN OSCILLATION
AND EL NINO ARE LIKELY TO BRING ABOUT A MAJOR PATTERN CHANGE TO
THE WEST COAST. ITEMS OF SIGNIFICANCE TO WATCH IN THE PATTERN
SHIFT...AMONG OTHERS DISCUSSED THE PREVIOUS TWO EVENINGS...WILL BE
THE EXTENT OF TROUGHING AND COLD AIR THAT SLIPS OUT OF WESTERN
CANADA AND INTO THE WESTERN UNITED STATES EARLY NEXT WEEK...AND
THEN EXACTLY WHERE THE STORM TRACK SETS UP. THE ECMWF OPERATIONAL
RUN IS THE MOST AGGRESSIVE WITH A RAPID PATTERN BREAKDOWN...WHEREAS
THE GFS40 HAS TENDED TO BE SLOWER WITH MORE ENERGY FOCUSED FARTHER
SOUTH. THE BOTTOM LINE IS THAT AS EARLY AS THIS WEEKEND...BUT MORE
LIKELY EARLY NEXT WEEK...STORMS ARE LIKELY TO IMPACT THE WEST
COAST. THESE WILL PACK SIGNIFICANT MOISTURE...AND ARE LIKELY TO
COME IN RAPID SUCCESSION. THE CLIMATE PREDICTION CENTERS MADDEN
JULIAN OSCILLATION EXPERT UPDATE FROM TODAY INDICATES ENHANCED
CHANCES FOR ABOVE AVERAGE PRECIPITATION FOR PRIMARILY THE CENTRAL
US WEST COAST DURING THE SECOND WEEK OF DECEMBER. LUTZ

&&

.AVIATION...AREAS OF IFR CIGS/VSBYS WILL PERSIST IN THE WEST SIDE
VALLEYS THROUGH TUESDAY MORNING...WITH SOME OF THE HIGHER
ELEVATION AREAS CLEARING TO VFR DURING THE AFTERNOON.
HOWEVER...THE LOW CONDITIONS WILL RETURN TO THE SAME AREAS TUESDAY
EVENING. ELSEWHERE...VFR CONDITIONS WILL PREVAIL.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL NOON PST FRIDAY FOR ORZ024-ORZ026-
        ORZ029-ORZ030-ORZ031.

CA...NONE.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS 
        UNTIL 4 AM PST TUESDAY FOR PZZ350-PZZ356.
     SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 AM PST WEDNESDAY FOR 
        PZZ376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST TUESDAY 
        FOR PZZ370-PZZ376.

$$

15/15/05