FXUS66 KPQR 150424
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST TUE FEB 14 2012

.SYNOPSIS...SHOWERS WERE DIMINISHING QUICKLY THIS EVENING AS A POTENT
COMPACT UPPER LEVEL LOW WAS MOVING RAPIDLY SOUTH AND WILL BE IN 
NORTHWEST NEVADA BY MORNING. CONSIDERABLE LOW LEVEL MOISTURE WILL 
REMAIN IN ITS WAKE...WITH A MIXTURE OF FOG AND LOW CLOUDS 
EXPECTED...AND ONLY SLOW CLEARING WEDNESDAY UNDER A BUILDING UPPER 
LEVEL RIDGE. ANOTHER PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE IN 
THURSDAY BUT WEAKEN AS IT COMES ONSHORE WITH MUCH HIGHER SNOW LEVELS.
THE FRONTAL BOUNDARY MAY STALL OVER OUR AREA THURSDAY NIGHT. THE NEXT
POSSIBLY STRONGER SYSTEM NOW LOOKS AS THOUGH IT WILL COME ONSHORE 
FRIDAY AND EARLY FRIDAY NIGHT...WITH MUCH LOWER SNOW LEVELS AGAIN 
FRIDAY NIGHT AND SATURDAY.
&&

.SHORT TERM...SHOWERS ARE DIMINISHING THIS EVENING FROM THE NORTH AS
THE POTENT COMPACT SYSTEM THAT MOVED INTO THE AREA EARLIER TODAY WAS
MOVING QUICKLY SOUTH...AND WILL BE IN NORTHWEST NEVADA BY EARLY
WEDNESDAY. THIS SYSTEM BROUGHT SNOW TO THE MOUNTAINS TO A BIT BELOW
1000 FEET TODAY AS A NICE POCKET OF COLDER AIR MOVED THROUGH. THIS
COLDER AIR RESULTED IN AN UNSTABLE AIR MASS TODAY WITH NUMEROUS
REPORTS OF SMALL HAIL...SOME OF WHICH COVERED THE GROUND...BUT NO
LIGHTNING ON OUR LIGHTNING DETECTION NETWORK.

THE AIR MASS IS QUITE MOIST IN THE WAKE OF THIS SYSTEM...WITH LOTS OF
LOW CLOUDS. IF WE DO GET ANY BREAKS...FOG WILL BE QUICK TO FORM
OVERNIGHT AND WEDNESDAY MORNING. GRADIENTS ARE RATHER WEAK ON
WEDNESDAY...SO THE VALLEY LOW CLOUDS AND FOG WILL BE SLOW TO BREAK
OUT...THOUGH THERE SHOULD BE MORE SUNSHINE AT HIGHER ELEVATIONS.

STABLE CONDITIONS SHOULD PERSIST WEDNESDAY NIGHT WITH MORE AREAS OF
FOG AND LOW CLOUDS REDEVELOPING ESPECIALLY IN THE VALLEYS.

THE NEXT SYSTEM IS EXPECTED TO ARRIVE THURSDAY. CURRENTLY WITH
IMPRESSIVE MOISTURE ON THE IR SATELLITE OUT NEAR 45N/145W...THIS
SYSTEM IS FORECAST TO WEAKEN CONSIDERABLY AS IT MOVES ONSHORE
THURSDAY. IT SLIGHTLY FLATTENS THE UPPER RIDGE OVER THE PACIFIC
NORTHWEST BUT 500 MB HEIGHTS REMAIN NEAR 564 DM. THUS THE SYSTEM WILL
WEAKEN AND SNOW LEVELS WILL RISE CONSIDERABLY...TO ABOVE ALL THE
CASCADE PASSES.

THE MODELS INDICATE THAT THE ASSOCIATED FRONTAL BOUNDARY MAY STALL
OVER OUR AREA THURSDAY NIGHT WITH DECREASING PRECIPITATION. THEN THE
NEXT POTENTIALLY STRONGER SYSTEM IS NOW EXPECTED TO ARRIVE 
FRIDAY...EARLIER THAN MODEL RUNS FROM JUST A DAY AGO. THIS SYSTEM 
COULD BRING WINDY CONDITIONS TO THE COAST...AND A GOOD SHOT OF RAIN 
TO SOUTHWEST WASHINGTON AND NORTHWEST OREGON. SNOW LEVELS WILL 
LIKELY DROP DRAMATICALLY FRIDAY NIGHT AND SATURDAY INTO THE CASCADE 
FOOTHILLS AND THE COASTAL MOUNTAINS AGAIN. TOLLESON

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...A SLIGHTLY
STRONGER SYSTEM APPROACHES THE AREA FRI EVENING AND SLIDES INLAND
SATURDAY MORNING. THIS SYSTEM LOOKS TO HAVE SPED UP A BIT IN THE
CURRENT MODEL RUNS. THIS SYSTEM BRINGS A CLOSED SFC LOW CLOSE TO THE
COAST...THOUGH MODELS DIFFER ON THE LOCATION THE LOW COMES ASHORE.
DEPENDING ON THE LOCATION...THE COAST COULD SEE A DECENT ROUND OF
STRONG WINDS OVERNIGHT FRI NIGHT...SO THIS BEARS WATCHING. THIS
SYSTEM PASSES THROUGH SATURDAY WITH SNOW LEVELS DROPPING DRAMATICALLY
BEHIND IT. FOR NOW...A GOOD AMOUNT OF SNOW ACCUMULATION IS POSSIBLE
OVER THE WEEKEND. ADDITIONAL SYSTEMS RIDING A STRONG JET TO THE NORTH
ATTEMPT TO BREAK THROUGH AN OFFSHORE RIDGE INTO NEXT WEEK. WITH NO
REAL AGREEMENT ON TIMING OF INDIVIDUAL SYSTEMS HAVE KEPT THE FORECAST
AREA UNDER GENERAL CHANCES OF PRECIPITATION THROUGH MID WEEK NEXT
WEEK. KMD/BROWN
&&

.AVIATION...AIR MASS BEGINNING TO STABILIZE. HOWEVER...PLENTY OF LOW
LEVEL MOISTURE IN REGION. UPPER LEVEL CLOUDS WILL PUSH OFF TO SE
OVERNIGHT...BUT LOW STRATUS LIKELY TO FORM...ESPECIALLY INLAND.
CURRENT THOUGHT HAS MORE IFR STRATUS AND AREAS OF FOG OVER N INTERIOR
AND COAST...WITH LOW MVFR OVER CENTRAL AND S WILLAMETTE VALLEY WHERE
LOW LEVEL INVERSION WILL BE BIT HIGHER OFF GROUND LEVEL. EXPECT
GRADUAL BUT SLOW CLEARING WED AM FROM S TO THE N... WITH AREAS FROM
KPDX TO KKLS CLEARING AROUND 21Z TO 23Z. ROCKEY.

KPDX AND APPROACHES...MOSTLY VFR THIS EVENING...WITH BREAKS IN THE
CIG THROUGH 07Z. AFTERWARDS...MAY HAVE BRIEF PERIOD OF JUST SCATTERED
CLOUDS PROBABLY BETWEEN 07Z AND 10Z. HOWEVER LOW STRATUS AND FOG WILL
BE FORMING AFTER MIDNIGHT. LIKELY TO BE IFR STRATUS WITH 2 TO 4 MILE
VIS IN FOG. IF CLEARING BREAKS ARE LONG ENOUGH THERE IS MODERATE TO
HIGH POTENTIAL TO HAVE LOWER VIS AND LOWER STATUS. SUSPECT THESE
CONDITIONS STAY MORE TO N AND W OF KPDX.
&&

.MARINE...HIGH PRES NOW BUILDING IN OVER THE WASHINGTON COASTAL
WATERS...AND WILL PUSH INLAND TONIGHT AND WED. WINDS HAVE BEEN EASING
THIS EVENING...AND NOW IN 10 TO 15 KT RANGE. WILL LOWER ADVISORIES
FOR WIND. WINDS REMAIN RATHER BENIGN UNTIL THU. ON OTHER HAND...SEAS
WILL STAY UP...MAINLY 12 TO 14 FT THROUGH THU. NEXT FRONT LIKELY
RAISES WINDS AGAIN ON THU...WITH A STRONGER SYSTEM BRINGING POTENTIAL
GALES INTO THE REGION LATER FRI AND SAT.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TONIGHT AND WED ON ALL
    COASTAL WATERS BETWEEN CAPE SHOALWATER AND FLORENCE.
     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR CONDITIONS TONIGHT
    AND WED. 
&&

$$

MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.