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000
FXUS66 KPQR 200403
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
903 PM PDT WED JUN 19 2013

.SYNOPSIS...PERSISTENT UPPER LEVEL LOW PRESSURE CONTINUES TO BRING
CLOUDS AND SHOWERS TO SOUTHWEST WASHINGTON AND NORTHWEST OREGON.
TEMPERATURES THROUGH THURSDAY WILL BE WELL BELOW NORMAL. SHOWERS ON
THE DECREASE THURSDAY AND FRIDAY AS THE UPPER LOW PUSHES EAST.
TEMPERATURES WILL CLIMB BACK CLOSER TO NORMAL FRIDAY AND SATURDAY
WITH SOME RELATIVELY DRIER WEATHER...BUT IT APPEARS AN ACTIVE
PACIFIC JET STREAM WILL BRING MORE WET WEATHER SUNDAY INTO EARLY
NEXT WEEK.

&&

.SHORT TERM...EVENING UPDATE...MAIN EXCITEMENT CENTERED AROUND A
FUNNEL CLOUD WHICH FORMED NORTHWEST OF THE PORTLAND AIRPORT AROUND 3
PM AND LASTING AROUND 5 MINUTES. PUBLIC PHOTOS REVEALED A VERY THIN
ROPE STRUCTURE. NO DAMAGE WAS REPORTED BUT IT CERTAINLY MADE FOR A
NEWSWORTHY EVENT GIVEN RECENT HISTORY AROUND THE PACNW. SUSPECT VERY
WEAK SPEED SHEAR WHERE 5 TO 10 KTS NEAR THE SURFACE INCREASED TO 15
TO 20 KTS JUST A COUPLE THOUSAND FEET OFF THE GROUND CREATED A
HORIZONTAL SPINNING VORTEX...VERY MUCH LIKE PUSHING A PIPE ACROSS A
TABLE BY ROLLING IT WITH YOUR HAND. THIS SPINNING TUBE OF AIR
CROSSED PATHS WITH LOCALIZED MODERATE UPDRAFT AND BRIEFLY BECAME
VERTICALLY ORIENTED THUS PRODUCING THE FUNNEL CLOUD. CHECK OUR
FACEBOOK PAGE (POSTS BY OTHERS) FOR A PICTURE SUBMITTED BY THE
PUBLIC. FURTHER EVIDENCE OF THE STRONG UPDRAFTS BECAME BY SEVERAL
CELLS WHICH PRODUCED STRONG SHOWER ACTIVITY VERY QUICKLY IN THEIR
SHORT LIFETIMES.

FEEL THE LAST GASP OF MODERATE SHOWER ACTIVITY IS UNDERWAY AS WE
REACH SUNSET AND BEGIN TO LOSE THE THERMAL TRIGGERING AT THIS HOUR.
ALSO...MODELS AND SATELLITE INDICATE A SHORTWAVE ROUNDING THE WEST
SIDE OF THE ELONGATED UPPER LOW LATER TONIGHT BUT IT APPEARS IT WILL
BE HEADING SOUTH OF THE AREA. AS SUCH...HAVE DECIDED TO CUT BACK ON
SHOWER COVERAGE FOR OVERNIGHT TONIGHT AND TOMORROW MORNING WITH THE
BIGGEST DECREASE FOR THE CASCADES AND FOOTHILLS. STILL EXPECT SOME
SHOWERS TO REMAIN UNDER MINIMAL OROGRAPHIC ENHANCEMENT...HOWEVER. NO
FURTHER CHANGES MADE WITH REMAINING DISCUSSIONS FOLLOWING. /JBONK

LATE TONIGHT THROUGH SATURDAY...TEMPS BEGIN TO WARM ALOFT TONIGHT AS
THE CORE OF COLD AIR ALOFT DRIFTS EAST OF THE CASCADES. THIS WILL BE
ANOTHER FACTOR CUTTING THE POTENTIAL FOR INSTABILITY. NAM BUFR
SOUNDINGS SUGGEST THAT BY THURSDAY MORNING WE SHOULD BE UNDER THE
INFLUENCE OF A STRONG CAPPING INVERSION NEAR 700 MB SO ANY SHOWERS
THURSDAY SHOULD BE SHALLOW. WITH A LITTLE MORE SUNSHINE TEMPS MAY BE
SLIGHTLY WARMER THU BUT STILL BELOW NORMAL.

THE UPPER LOW MEANDERS TOWARD THE IDAHO PANHANDLE FRIDAY...BUT STILL
REMAINS CLOSE AND BROAD ENOUGH TO ALLOW WRAPAROUND MOISTURE TO KEEP
THE SHOWER THREAT GOING FOR OUR NORTHERN ZONES. TEMPS WILL CONTINUE
THEIR SLOW RECOVERY AS THE AIR MASS SLOWLY WARMS UP...WITH THE DRYING
AND WARMING TREND BACK TOWARD NORMAL CONTINUING INTO SATURDAY AS THE
UPPER LOW FINALLY TRIES TO MOVE ACROSS THE NORTHERN ROCKIES. HOWEVER
A STRONG PACIFIC JET WILL BE KNOCKING ON OUR DOOR BY THEN...AIMING TO
BRING A PROLONGED PERIOD OF UNSEASONABLY WET WEATHER TO THE PACIFIC
NORTHWEST FOR EARLY NEXT WEEK.WEAGLE

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...THE LATEST MEDIUM
RANGE MODEL RUNS ARE SHOWING FAIRLY GOOD AGREEMENT IN THE EXTENDED
PORTION OF THE FCST. AFTER A BRIEF PERIOD OF DRY WEATHER SAT...THE
MODELS ARE NOW SHOWING A LOW COMING ONSHORE SAT NIGHT INTO SUN
MORNING. ALTHOUGH SOME MODEL RUNS ARE KEEPING THE BEST PRECIP TO OUR
SOUTH...THE ENSEMBLES SOLUTIONS ARE SHOWING LIKELY POPS OVER MUCH OF
OUR FCST AREA DURING THE DAY SUN. THEN A DEEP CLOSED UPPER LEVEL LOW
IS PROGGED TO DROP SOUTH AND STALL OVER THE NE PAC FOR MOST IF NOT
ALL OF NEXT WEEK. THE BEST CHANCE FOR SIGNIFICANT PRECIP APPEARS TO
BE MON NIGHT INTO TUE...WHEN THE MODELS SEEM TO AGREE THAT A JUICY
FRONT WILL BRING A SLUG OF HEAVY PRECIP TO THE REGION. OTHERWISE...
EXPECT THAT THE PAC NW WILL REMAIN IN A CLOUDY AND WET PATTERN
THROUGH MOST OF NEXT WEEK. TEMPS WILL ALSO LIKELY BE RUNNING SEVERAL
DEG BELOW NORMAL. PYLE

&&

.AVIATION...A SHOWERY UNSTABLE AIRMASS WILL LEAD TO MAINLY VFR
CONDITIONS ACROSS THE AREA. THE LOWER ATMOSPHERE SHOULD REMAIN
MODESTLY UNSTABLE EVEN OVERNIGHT SO CIGS SHOULD GENERALLY REMAIN
VFR...BUT MVFR CIG DEVELOPMENT WILL BE POSSIBLE. CONFIDENCE IN
TIMING AND LOCATION OF ANY SUCH LOWER CIGS IS LOW SO KEPT MVFR
CONDITIONS LIMITED IN THE TAFS.

KPDX AND APPROACHES...EXPECT VFR CONDITIONS WITH SCATTERED
SHOWERS THROUGH THE EVENING. CONDITIONS SHOULD GENERALLY REMAIN
VFR OVERNIGHT INTO THURSDAY...BUT CANNOT RULE OUT AN OCCASIONAL
MVFR CIG...PARTICULARLY TOWARD THURSDAY MORNING.

&&

.MARINE...EXPECT TRANQUIL WINDS AND SEAS THROUGH SATURDAY AS HIGH
PRESSURE MOVES OVER THE NORTHEAST PACIFIC. A SERIES OF WEAK STORM
SYSTEMS WILL LIKELY CAUSE WINDS AND SEAS TO INCREASE EARLY NEXT
WEEK. HOWEVER...SEAS SHOULD REMAIN BELOW 10 FT AND LITTLE MORE
THAN SMALL CRAFT ADVISORIES FOR WIND GUSTS OF 25-30KT APPEAR
POSSIBLE MONDAY THROUGH WEDNESDAY.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&

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.