532
FXUS66 KMFR 161548
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
848 AM PDT WED OCT 16 2013
.DISCUSSION...OTHER THAN TO MAKE A FEW ADJUSTMENTS TO THE SKY COVER
THIS MORNING AND AFTERNOON, THE FORECAST IS ON TRACK. A WEAK
SHORTWAVE IS MOVING INTO HE AREA AND THAT HAS BROUGH HIGH AND MID
LEVEL CLOUDS INTO THE AREA THIS MORNING. THIS WILL MOVE SOUTH THIS
AFTERNOON AND SKIES WILL CLEAR OUT FROM NORTH TO SOUTH. CLEAR
SKIES ARE EXPECTED TONIGHT WITH TEMPERATURES DROPPING RATHER
QUICKLY ONCE AGAIN AROUND AND AFTER SUNSET. WE'LL TAKE A CLOSER
LOOK AT MIN TEMPERATURES FOR TONIGHT AND DETERMINE IF ANOTHER
FREEZE WARNING WILL BE NECESSARY FOR THE ROGUE...ILLINOIS AND
APPLEGATE VALLEYS. -PETRUCELLI
&&
.AVIATION...LIFR CONDITIONS WILL TRANSITION TO MVFR AT KRBG
BETWEEN 18-19Z THEN VFR BETWEEN 20-21Z. LOW CLOUDS WITH IFR CIGS
ARE LIKELY AGAIN LATE THIS EVENING AND INTO WEDNESDAY MORNING
ALONG THE COAST AND UMPQUA BASIN. ELSEWHERE VFR CONDITIONS WILL
CONTINUE FOR THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 251 AM PDT WED OCT 16 2013/
DISCUSSION...NO BIG CHANGES IN THE FORECAST...AS THE BIG BUBBLE
OF HIGH PRESSURE LOOKS TO REMAIN IN CONTROL FOR THE DURATION OF
THE FORECAST PERIOD. CURRENTLY...THE LARGE BLOCKING RIDGE OVER THE
EASTERN PACIFIC REMAINS FIRMLY IN CONTROL...KEEPING THE STORM
TRACK WELL AWAY FORM THE FORECAST AREA. MODEL SOLUTIONS...ALTHOUGH
HAVING DIFFICULTY WITH THE BLOCK GOING INTO THE LONG TERM...ARE IN
GOOD AGREEMENT. PERSISTENCE WILL LIKELY BE THE WISE FORECAST CHOICE
FOR THE TIME BEING.
A WEAK WAVE WILL PASS OVER THE REGION THIS MORNING AS IT MAKES
ITS WAY SOUTH ALONG THE EASTERN PERIPHERY OF THE RIDGE. LITTLE MORE
THAN INCREASED CLOUDINESS IS EXPECTED WITH THIS FEATURE...ALTHOUGH
ITS INFLUENCE WILL ALSO WEAKEN THE OFFSHORE FLOW TODAY. THIS WILL
RESULT IN A HALT TO THE CHETCO EFFECT...ALLOWING THE BROOKINGS
AREA TO RETURN TO COOLER TEMPERATURES TODAY. HOWEVER...OFFSHORE
FLOW AND WARMER TEMPERATURES WILL RETURN THURSDAY.
OTHERWISE...THERE WILL BE ONLY MINOR CONCERNS AS OFFSHORE
FLOW AND QUIET WEATHER REMAIN IN PLACE FOR THE NEXT WEEK OR SO.
THE FIRST OF THESE CONCERNS IS THE POTENTIAL FOR COASTAL AND WEST
SIDE VALLEY FOG DURING THE OVERNIGHT AND EARLY MORNING HOURS.
ALTHOUGH THE AIR MASS IS DRY...HIGH PRESSURE AND COOLING AT THE
SURFACE COULD STILL PRODUCE SOME FOG. MUCH OF THIS SHOULD REMAIN
CONCENTRATED NORTH OF THE UMPQUA DIVIDE...BUT CAN NOT RULE OUT
OTHER LOCATIONS EITHER. OF OTHER CONCERN WILL BE COLD TEMPERATURES
IN THE ROGUE...ILLINOIS...AND APPLEGATE VALLEYS...WHICH COULD
RESULT IN FROST OR FREEZE CONDITIONS IN THE EARLY MORNING.
CURRENTLY...A FREEZE WARNING IS IN EFFECT IN THESE AREAS.
HOWEVER...TEMPERATURES SHOULD BE SLIGHTLY WARMER THROUGH THE
WEEK...SO THE AREA OF COVERAGE SHOULD DECREASE.
FOR THE LONG TERM...MODELS SHOW THE BLOCKING RIDGE SHIFTING EAST
SLIGHTLY...ALTHOUGH THE EVOLUTIONS OF THE RIDGE DIFFERS BETWEEN
THE GFS AND ECMWF. THE FORMER TRANSITIONS THE FEATURE INTO MORE OF
A REX TYPE BLOCK...WHILE THE LATTER PRODUCES A LOP-SIDED OMEGA.
THERE IS LITTLE CONFIDENCE IN EITHER SOLUTION...ESPECIALLY AS
HEMISPHERICAL MODELS SHOW A POSSIBLE KICKER MOVING IN MIDWEEK.
WITH THE HIGH UNCERTAINTY...HAVE OPTED TO KEEP MUCH OF THE CURRENT
FORECAST TRENDS INTACT...BUT WITH SLIGHTLY WARMING TEMPERATURES TO
COINCIDE WITH THE IDEA OF THE RIDGE AXIS EDGING CLOSER TO THE
FORECAST AREA. DRY CONDITIONS WITH MILD DAYTIME AND COOL TO CHILLY
NIGHTTIME TEMPERATURES WILL THEREFORE CONTINUE THROUGHOUT THE TERM.
-BPN
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 AM PDT THIS
MORNING FOR PZZ370.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT THIS MORNING FOR
PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THURSDAY
FOR PZZ376.
$$