Forecast: Forecast Discussion | 7 Day Forecast
Forecast Discussion for MFR NWS Office
000
FXUS66 KMFR 061658
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
858 AM PST MON FEB 6 2012
.DISCUSSION...
THE STAGNANT CONDITIONS OF THE LAST FEW DAYS WILL BE SLIGHTLY
INTERRUPTED BY THE SPLITTING FRONTAL SYSTEM MOVING IN
TONIGHT THROUGH TUESDAY...BUT THEN HIGH PRESSURE RIDGING WILL
REBUILD AND PERSIST THROUGH THURSDAY.
THERE ARE INCREASING INDICATIONS...LED BY THE MEDIUM TO LONGER
RANGE EUROPEAN CENTER MODEL GUIDANCE...THAT WE WILL MOVE INTO A
COOLER AND SOMEWHAT WETTER PATTERN OVER THE AREA BEGINNING FRIDAY
INTO NEXT WEEKEND. AT THIS POINT CHANCES FOR PRECIPITATION LOOK
BEST OVER WESTERN SECTIONS OF THE AREA...PRIMARILY FROM THE
CASCADES WESTWARD. HOWEVER...WITH THE ARCTIC OSCILLATION GOING
FROM NEGATIVE TO NEAR NEUTRAL THERE WILL ALSO BE THE POTENTIAL FOR
SOME PRECIPITATION OVER EASTERN PORTIONS OF THE AREA...ESPECIALLY
AS WE HEAD INTO THE MIDDLE OF THIS MONTH.
&&
.CLIMATE...
BEYOND MID MONTH...WHILE THERE HAVE BEEN SOME FLUCTUATIONS IN THE
GUIDANCE...THE GENERAL CONSENSUS IS THAT WE ARE MOST LIKELY TO GO
INTO COOLER THAN NORMAL TO NEAR NORMAL TEMPERATURE CONDITIONS AND
WETTER TO NEAR NORMAL PRECIPITATION CONDITIONS OVER THE AREA
FOR THE SECOND HALF OF THE MONTH INTO EARLY MARCH. WHILE THIS IS
WHAT WE WOULD NORMALLY EXPECT WITH LA NINA AND OTHER SEASONAL
INDICATORS IN PLACE...THE FACT THAT THE MODEL GUIDANCE IS ALSO
INDICATING THIS INCREASES OUR CONFIDENCE THAT WEATHER CONDITIONS
WILL BE GETTING BACK CLOSER TO WHAT WE WOULD EXPECT.
&&
.AVIATION...
LIFR AREAS OF FREEZING FOG IN THE ILLINOIS VALLEY...AND IN AND
AROUND GRANTS PASS AND ROSEBURG ARE EXPECTED TO DISSIPATE LATE
THIS MORNING. OTHERWISE VFR CONDITIONS ARE EXPECTED. LATE TONIGHT
FOG IS AGAIN EXPECTED IN THE SAME AREAS AS IS BEING OBSERVED THIS
MORNING...THOUGH HIGH CLOUDS MAY LIMIT THE DURATION AND EXTENT OF
THIS...ESPECIALLY OVER SOUTHWESTERN SECTIONS OF THE AREA.
&&
.PREV DISCUSSION... /ISSUED 245 AM PST MON FEB 6 2012/
DISCUSSION...ANOTHER WARM AND DRY DAY IS EXPECTED WITH CONTINUED
OFFSHORE FLOW AND RIDGING OVERHEAD. AFTER FOG CLEARS FROM THE
ILLINOIS VALLEY AND UMPQUA BASIN...ONLY HIGH CLOUDS ARE EXPECTED
ACROSS THE FORECAST AREA. THESE CLOUDS SHOULD KEEP HIGH TEMPERATURES
A FEW DEGREES COOLER THAN YESTERDAY BUT STILL 5 TO 10 DEGREES ABOVE
NORMAL. SOME OF THE INCREASING SOUTH WINDS ALOFT SHOULD MIX DOWN TO
THE SURFACE IN THE SHASTA VALLEY...AND RIDGES FROM THE CASCADES WEST
WILL BECOME BREEZY AS WELL.
A STRETCHED OUT FRONTAL BOUNDARY AND ITS ENERGY WILL GENERALLY DRIFT
SOUTH OF OUR FORECAST AREA...GENERATING SOME LIGHT PRECIPITATION
MAINLY OVER WESTERN SISKIYOU COUNTY AND POINTS ALONG AND WEST OF THE
COAST RANGE. TEMPERATURES WILL DROP BACK TO NEAR NORMAL TUESDAY
GIVEN THE THICKER CLOUD COVER. TEMPERATURES WILL WARM AGAIN
WEDNESDAY INTO THURSDAY AS RIDGING BUILDS BACK OVER NORTHERN
CALIFORNIA AND SOUTHERN OREGON. GIVEN A CHANGE IN AIR MASS AND
HIGHER DEW POINTS EXPECTED BY THURSDAY...A CHANCE OF FOG IN MOST
WEST SIDE VALLEYS IS REASONABLE AND IS REFLECTED IN THE FORECAST.
THE GFS AND ECMWF FEATURE SUBTLE DIFFERENCES IN THE 500MB HEIGHT
PATTERN INTO THE EARLY PART OF THE WEEKEND...BUT THIS RESULTS IN BIG
DIFFERENCES FOR OUR FORECAST AREA. IN GENERAL...THE GFS PORTENDS
CONTINUED DRY AND WARM CONDITIONS WHILE THE ECMWF SUGGESTS A SHIFT
TO COOLER AND WETTER CONDITIONS. CONFIDENCE IS LOW IN ANY SPECIFIC
OUTCOME AND ENSEMBLES ARE NOT HELPING MUCH. SO A TREND FOR
INCREASING CHANCES OF PRECIPITATION LATE NEXT WEEK INTO THE WEEKEND
IS GOOD AND LEFT IT ALONE.
AVIATION...GOOD FLYING WEATHER IS EXPECTED TODAY OVER MOST OF THE
FORECAST AREA. THE EXCEPTIONS ARE THE ILLINOIS VALLEY AND UMPQUA
BASIN WHERE FOG AND IFR CONDITIONS WILL LIKELY LAST UNTIL LATE
MORNING. ALL LOCATIONS WILL HAVE VFR CONDITIONS THIS AFTERNOON...AND
LIMITED...IF ANY FOG IS EXPECTED TONIGHT WITH MID AND HIGH CLOUDS
MOVING IN. ONE POSSIBLE IMPACT TO AVIATION WILL BE INCREASING
SOUTH WINDS ALOFT LATE THIS AFTERNOON INTO TONIGHT...LIKELY PRODUCING
TURBULENCE NEAR HIGH TERRAIN AREAS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PZ...NONE.
$$
BTL/NSK
NWS MFR Office Area Forecast Discussion
