[top]
000
FXUS66 KMFR 190022 CCA
AFDMFR
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MEDFORD OR
509 PM PDT SAT MAY 18 2013
CORRECTED WORDING AND ADJUSTED SNOW LEVEL MENTIONED FOR WEDNESDAY
MORNING
.DISCUSSION...THE REGION IS IN FOR A TEMPERATURE ROLLER COASTER
RIDE AS AN ACTIVE PATTERN REMAINS OVER THE WEST COAST THROUGH THE
NEXT WEEK. THE COLD FRONT IS MOVING THROUGH THE REGION TODAY WITH
SHOWERS CONTINUING BEHIND IT AS LAPSE RATES REMAIN MODERATE AND
FLOW BECOMES ONSHORE. AS SURFACE COOLING SLOWLY PROGRESSES UNDER
THE SC DECK IN NW PORTIONS OF THE AREA, SHOWERS LINGER THE LONGEST
THERE THROUGH THE EVENING AND OVERNIGHT. UPPER LEVEL RIDGE BUILDS
OVER THE REGION BY LATE TONIGHT WITH OFFSHORE FLOW DEVELOPING OVER
THE SOUTHERN COASTAL RANGE BY SUNDAY MORNING. WITH CLEARING
EXPECTED SUNDAY IN THE EXPANDING OFFSHORE FLOW, WE`LL SEE A WARM
UP OF AROUND TEN DEGREES COMPARED TO TODAY. OFFSHORE FLOW REMAINS
OVERNIGHT SUNDAY WITH HIGHER TEMPS ON THE RIDGES STARTING THE
REGION OFF TO ANOTHER GOOD WARM UP MONDAY WITH TEMPS WARMING
AROUND ANOTHER TEN DEGREES. AN UPPER LEVEL LOW MOVES INTO THE
REGION FROM THE NORTHWEST MONDAY NIGHT WITH A COLD FRONT MOVING
THROUGH TUESDAY. MODEL 850 MB TEMPS ARE IN THE LOWER TEENS TUESDAY
MORNING...DROPPING TO AROUND 0 C RIGHT BEHIND THE FRONT. HIGH
TEMPERATURES OVER MUCH OF THE WEST SIDE MIGHT BE IN THE MORNING
WITH TEMPS DROPPING THROUGH THE LATER AFTERNOON AS THE FRONT MOVES
IN COMBINING WITH SHOWERS. BY WEDNESDAY MORNING THE EC AND GFS
HAVE COME IN MUCH BETTER AGREEMENT WITH THE COLD AIR MASS...BOTH
SHOWING 850 TEMPS IN THE -3 TO -4 C RANGE...BRINGING A LATE SEASON
DUSTING OF SNOW POSSIBLY AS LOW AS 3000 FEET. WITH THE VERY WARM
TEMPERATURES AND SUN FOR THE PRECEDING DAYS THIS SNOW SHOULD MELT
VERY QUICKLY EXCEPT FOR LOCATIONS WHERE THERE IS STILL SNOW ON THE
GROUND. HAVE MORE BROAD-BRUSHED THE REMAINDER OF THE EXTENDED AS
BOTH THE GFS AND THE EC WOBBLE A CUTOFF LOW OVER THE PAC NW
THROUGH THE REMAINDER OF THE WEEK. THE GFS HAS REMAINED THE MOST
CONSISTENT WITH YESTERDAYS MUCH MORE SOUTHERLY POSITION OF THE EC
NOW TRENDING CLOSER TO YESTERDAY`S GFS SOLUTION...AND HAVE LEANED
MORE HEAVILY TOWARDS THE GFS WITH THIS IN MIND.
&&
.AVIATION...CEILINGS WILL LOWER ACROSS THE AREA THROUGH THIS
EVENING AS A COLD FRONT CONTINUES TO MOVE TOWARD THE COAST. MVFR
CONDITIONS ALONG THE COAST WILL SPREAD INTO THE UMPQUA BASIN
THROUGH THIS EVENING. EXPECT OBSCURATIONS TO BE NEAR TOTAL ACROSS
THE COASTAL MOUNTAINS, SPREADING TO THE CASCADES, SISKIYOUS, AND
MARBLE MOUNTAINS THROUGH THIS EVENING. THERE IS A SLIGHT CHANCE OF
AFTERNOON AND EVENING THUNDERSTORMS OVER LAKE AND MODOC COUNTIES.
THIS EVENING EXPECT SOME IFR ALONG THE COAST AND MVFR IN THE
UMPQUA BASIN AS WELL AS IN NORTHWEST FLOW UPSLOPE AREAS ALONG AND
NEAR THE CASCADES AND SISKIYOUS. OTHERWISE VFR SHOULD PREVAIL.
OVERNIGHT PARTIAL CLEARING WILL OCCUR WITH PATCHY MVFR DISSIPATING
TO MOSTLY IN THE UMPQUA BASIN. IT WILL CLEAR TO VFR ALL AREAS
BETWEEN SUNRISE AND NOON ON SUNDAY AS HIGH PRESSURE BECOMES WELL
ESTABLISHED. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM
SUNDAY TO 5 AM PDT TUESDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM SUNDAY TO 5
AM PDT TUESDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM SUNDAY TO 11 PM PDT
MONDAY FOR PZZ350-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM SUNDAY TO 11
PM PDT MONDAY FOR PZZ350-370.
SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TO 2 PM PDT SUNDAY FOR
PZZ376.
HAZARDOUS SEAS WARNING FROM 2 PM SUNDAY TO 11 PM PDT MONDAY FOR
PZZ376.
GALE WARNING FROM 2 PM SUNDAY TO 11 PM PDT MONDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TO 2 PM PDT
SUNDAY FOR PZZ376.
$$
SVEN
[top]
000
FXUS66 KPDT 182231 AAA
AFDPDT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
330 PM PDT SAT MAY 18 2013
UPDATED AVIATION DISCUSSION
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...A WEAK PACIFIC SYSTEM
WILL CONTINUE TO MOVE ACROSS THE REGION TONIGHT. THIS SYSTEM WILL
THEN SHIFT SOUTHEAST ACROSS IDAHO AND WYOMING ON SUNDAY. WILL
CONTINUE TO SEE ISOLATED TO SCATTERED SHOWERS ACROSS MUCH OF THE
AREA THIS EVENING, WITH THE BEST CHANCES ACROSS CENTRAL AND
EAST-CENTRAL OREGON. THESE SHOWERS WILL GRADUALLY DECREASE LATE THIS
EVENING AND OVERNIGHT, WITH ONLY A FEW SHOWERS LINGERING OVER THE
MOUNTAINS TOWARDS DAYBREAK. THERE REMAINS ENOUGH INSTABILITY LATE
THIS AFTERNOON INTO EARLY THIS EVENING FOR STRAY THUNDERSTORMS OVER
THE SOUTHERN OREGON BLUE MOUNTAINS, THE JOHN DAY BASIN AND THE JOHN
DAY-OCHOCO HIGHLANDS. WINDS WILL CONTINUE BREEZY TO LOCALLY WINDY
ACROSS THE AREA THROUGH THIS EVENING, THEN GRADUALLY DECREASE
OVERNIGHT. LOCALLY BREEZY WINDS WILL CONTINUE THROUGH SUNDAY,
PRIMARILY IN AND NEAR THE COLUMBIA RIVER GORGE AND IN THE KITTITAS
VALLEY. LINGERING MOISTURE COMBINED WITH A NORTHWEST FLOW ALOFT WILL
KEEP A FEW SHOWERS GOING OVER SOME AREA MOUNTAINS SUNDAY THROUGH
SUNDAY EVENING DUE TO UPSLOPE AFFECTS. OTHERWISE HIGH PRESSURE ALOFT
AND AT THE SURFACE WILL BUILD INTO THE REGION SUNDAY NIGHT INTO
MONDAY. THUS EXPECT DRY CONDITIONS LATE SUNDAY NIGHT THROUGH MONDAY
EVENING. HIGH TEMPS MONDAY WILL WARM 7-10 DEGREES OVER SUNDAY
AFTERNOON. AN APPROACHING PACIFIC SYSTEM MAY SPREAD SOME LIGHT
PRECIP TO THE WASHINGTON CASCADE CREST AREA LATE MONDAY NIGHT,
OTHERWISE SHOULD CONTINUED DRY CONDITIONS WITH INCREASING CLOUDS. 90
.LONG TERM...TUESDAY THROUGH SATURDAY. CONFIDENCE IS HIGH THAT THE
PACIFIC NW WILL BE UNDER THE INFLUENCE OF A LARGE CLOSED LOW DURING
THE PERIOD. HOWEVER...CONFIDENCE IN THE EXACT PLACEMENT OF THE LOW
AND THE LOCATION/STRENGTH OF EMBEDDED SHORTWAVES IS LOW...ESPECIALLY
THURS-SAT. THE LARGE UPPER LOW WILL MOVE ONSHORE TUESDAY THEN WILL
BECOME BLOCKED BY AN AMPLIFIED RIDGE OVER THE MIDWEST. THIS COLD
LOW WILL RESULT IN UNSEASONABLY COLDER TEMPERATURES AND SHOWERY
CONDITIONS THROUGH THE EXTENDED PERIOD. SNOW LEVELS WILL LOWER
SIGNIFICANTLY LATE TUESDAY NIGHT AND WEDNESDAY MORNING...POSSIBLY AS
LOW AS 3500-4000 FEET. MODELS BEGIN TO DIVERGE ON THURSDAY. WHILE
THE ECMWF SWINGS THE LOW TO THE NORTHEAST ACROSS OREGON ON
FRIDAY...THE GFS IS FARTHER NORTH AND WEST WITH THE PRIMARY POSITION
OFFSHORE. EITHER WAY...THE PACIFIC NW WILL BE COOL AND SHOWERY
DURING THE LONG TERM PERIOD. WISTER
&&
.AVIATION...00Z TAFS. SCATTERED SHOWERS MAY CAUSE CIGS/VSBYS TO
BRIEFLY LOWER TO NEAR MVFR THIS AFTERNOON AND EVENING.
OTHERWISE...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. CIGS
WILL RANGE FROM 4-8000 FEET AGL...ALTHOUGH THERE WILL BE BREAKS IN
THE CLOUD COVER OVERNIGHT. SKIES WILL BE SCT-BKN ON SUNDAY WITH
BASES AROUND 7-10,000 FEET AGL. SUSTAINED WINDS OF 10-15 KNOTS
GUSTING TO 25 KNOTS CAN BE EXPECTED IN MOST AREAS THIS
EVENING...DIMINISH OVERNIGHT...THEN INCREASE TO 5-15 KNOTS ON
SUNDAY. WISTER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 46 70 44 76 / 20 10 0 0
ALW 50 71 49 77 / 20 10 0 0
PSC 48 77 42 80 / 10 10 0 0
YKM 42 74 40 78 / 10 10 0 0
HRI 48 75 41 79 / 20 10 0 0
ELN 46 72 43 78 / 10 10 0 0
RDM 35 67 32 76 / 20 10 0 0
LGD 44 65 40 73 / 20 20 0 0
GCD 40 67 36 76 / 30 10 0 0
DLS 50 71 44 81 / 20 10 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SUNDAY : GREEN
MONDAY : GREEN
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
90/85/85
000
FXUS66 KMFR 182200
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
300 PM PDT SAT MAY 18 2013
.DISCUSSION... THE REGION IS IN FOR A TEMPERATURE ROLLER COASTAL
RIDE AS ACTIVE PATTERN REMAINS OVER THE WEST COAST THROUGH THE
NEXT WEEK. THE COLD FRONT MOVING THROUGH THE REGION TODAY WITH
SHOWERS CONTINUING BEHIND AS LAPSE RATES REMAIN MODERATE AS FLOW
BECOMES ONSHORE. AS SURFACE COOLING SLOWLY PROGRESSES UNDER THE SC
DECK IN NW PORTIONS OF THE AREA SHOWERS LINGER THE LONGEST THROUGH
THE EVENING AND OVERNIGHT. UPPER LEVEL RIDGE BUILDS OVER THE
REGION BY LATE TONIGHT WITH OFFSHORE FLOW DEVELOPING OVER THE
SOUTHERN COASTAL RANGE BY SUNDAY MORNING. WITH THE CLEARING IN THE
EXPANDING OFFSHORE FLOW SKIES CLEAR AND THE REGION SEES A WARM UP
OF OVER TEN DEGREES TOMORROWS HIGHS WILL BE GENERALLY AROUND
TEN DEGREES HIGHER THAN TODAY`S. OFFSHORE FLOW REMAINS OVERNIGHT
SUNDAY WITH HIGHER TEMPS ON THE RIDGES STARTING THE REGION OFF TO
ANOTHER GOOD WARM UP MONDAY WITH TEMPS WARMING AROUND ANOTHER TEN
DEGREES. AN UPPER LEVEL LOW MOVES INTO THE REGION FROM THE
NORTHWEST MONDAY NIGHT WITH A COLD FRONT MOVING THROUGH TUESDAY.
850 MB TEMPS ARE IN THE LOWER TEENS TUESDAY MORNING...DROPPING TO
AROUND 0 C RIGHT BEHIND THE FRONT. HIGH TEMPERATURES OVER MUCH OF
THE WEST SIDE MIGHT BE IN THE MORNING WITH TEMPS DROPPING QUICKLY
THOUGH THE LATER AFTERNOON AS THE FRONT MOVES IN COMBINING WITH
SHOWERS. BY WEDNESDAY MORNING THE EC AND GFS HAVE COME IN MUCH
BETTER AGREEMENT WITH THE COLD AIR MASS...BOTH SHOWING 850 TEMPS
IN THE -3 TO -4 C RANGE...BRINGING A LATE SEASON DUSTING OF SNOW
TO POSSIBLY AS LOW AS 300 FEET. WITH THE VERY WARM TEMPERATURES
AND SUN FOR THE PRECEDING DAYS THIS SNOW SHOULD MELT VERY QUICKLY
EXCEPT FOR LOCATIONS WHERE THERE IS STILL SNOW ON THE GROUND. HAVE
MORE BROAD-BRUSHED THE REMAINDER OF THE EXTENDED AS BOTH THE GFS
AND THE EC WOBBLE A CUTOFF LOW OVER THE PAC NW THROUGH THE
REMAINDER OF THE WEEK. THE GFS HAS REMAINED THE MOST CONSISTENT
WITH YESTERDAYS MUCH MORE SOUTHERLY POSITION OF THE EC NOW
TRENDING CLOSER TO YESTERDAY`S GFS SOLUTION...AND HAVE LEANED MORE
HEAVILY TOWARDS THE GFS WITH THIS IN MIND.
&&
.AVIATION...CEILINGS WILL LOWER ACROSS THE AREA THROUGH THIS
EVENING AS A COLD FRONT CONTINUES TO MOVE TOWARD THE COAST. MVFR
CONDITIONS ALONG THE COAST WILL SPREAD INTO THE UMPQUA BASIN
THROUGH THIS EVENING. EXPECT OBSCURATIONS TO BE NEAR TOTAL ACROSS
THE COASTAL MOUNTAINS, SPREADING TO THE CASCADES, SISKIYOUS, AND
MARBLE MOUNTAINS THROUGH THIS EVENING. THERE IS A SLIGHT CHANCE OF
AFTERNOON AND EVENING THUNDERSTORMS OVER LAKE AND MODOC COUNTIES.
THIS EVENING EXPECT SOME IFR ALONG THE COAST AND MVFR IN THE
UMPQUA BASIN AS WELL AS IN NORTHWEST FLOW UPSLOPE AREAS ALONG AND
NEAR THE CASCADES AND SISKIYOUS. OTHERWISE VFR SHOULD PREVAIL.
OVERNIGHT PARTIAL CLEARING WILL OCCUR WITH PATCHY MVFR DISSIPATING
TO MOSTLY IN THE UMPQUA BASIN. IT WILL CLEAR TO VFR ALL AREAS
BETWEEN SUNRISE AND NOON ON SUNDAY AS HIGH PRESSURE BECOMES WELL
ESTABLISHED. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM SUNDAY TO 5 AM PDT
TUESDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM SUNDAY TO 5
AM PDT TUESDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM SUNDAY TO 11 PM PDT
MONDAY FOR PZZ350-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM SUNDAY TO 11
PM PDT MONDAY FOR PZZ350-370.
SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TO 2 PM PDT SUNDAY FOR
PZZ376.
HAZARDOUS SEAS WARNING FROM 2 PM SUNDAY TO 11 PM PDT MONDAY FOR
PZZ376.
GALE WARNING FROM 2 PM SUNDAY TO 11 PM PDT MONDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM TO 2 PM PDT
SUNDAY FOR PZZ376.
$$
SVEN
000
FXUS66 KPDT 182149
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
249 PM PDT SAT MAY 18 2013
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...A WEAK PACIFIC SYSTEM
WILL CONTINUE TO MOVE ACROSS THE REGION TONIGHT. THIS SYSTEM WILL
THEN SHIFT SOUTHEAST ACROSS IDAHO AND WYOMING ON SUNDAY. WILL
CONTINUE TO SEE ISOLATED TO SCATTERED SHOWERS ACROSS MUCH OF THE
AREA THIS EVENING, WITH THE BEST CHANCES ACROSS CENTRAL AND
EAST-CENTRAL OREGON. THESE SHOWERS WILL GRADUALLY DECREASE LATE THIS
EVENING AND OVERNIGHT, WITH ONLY A FEW SHOWERS LINGERING OVER THE
MOUNTAINS TOWARDS DAYBREAK. THERE REMAINS ENOUGH INSTABILITY LATE
THIS AFTERNOON INTO EARLY THIS EVENING FOR STRAY THUNDERSTORMS OVER
THE SOUTHERN OREGON BLUE MOUNTAINS, THE JOHN DAY BASIN AND THE JOHN
DAY-OCHOCO HIGHLANDS. WINDS WILL CONTINUE BREEZY TO LOCALLY WINDY
ACROSS THE AREA THROUGH THIS EVENING, THEN GRADUALLY DECREASE
OVERNIGHT. LOCALLY BREEZY WINDS WILL CONTINUE THROUGH SUNDAY,
PRIMARILY IN AND NEAR THE COLUMBIA RIVER GORGE AND IN THE KITTITAS
VALLEY. LINGERING MOISTURE COMBINED WITH A NORTHWEST FLOW ALOFT WILL
KEEP A FEW SHOWERS GOING OVER SOME AREA MOUNTAINS SUNDAY THROUGH
SUNDAY EVENING DUE TO UPSLOPE AFFECTS. OTHERWISE HIGH PRESSURE ALOFT
AND AT THE SURFACE WILL BUILD INTO THE REGION SUNDAY NIGHT INTO
MONDAY. THUS EXPECT DRY CONDITIONS LATE SUNDAY NIGHT THROUGH MONDAY
EVENING. HIGH TEMPS MONDAY WILL WARM 7-10 DEGREES OVER SUNDAY
AFTERNOON. AN APPROACHING PACIFIC SYSTEM MAY SPREAD SOME LIGHT
PRECIP TO THE WASHINGTON CASCADE CREST AREA LATE MONDAY NIGHT,
OTHERWISE SHOULD CONTINUED DRY CONDITIONS WITH INCREASING CLOUDS. 90
.LONG TERM...TUESDAY THROUGH SATURDAY. CONFIDENCE IS HIGH THAT THE
PACIFIC NW WILL BE UNDER THE INFLUENCE OF A LARGE CLOSED LOW DURING
THE PERIOD. HOWEVER...CONFIDENCE IN THE EXACT PLACEMENT OF THE LOW
AND THE LOCATION/STRENGTH OF EMBEDDED SHORTWAVES IS LOW...ESPECIALLY
THURS-SAT. THE LARGE UPPER LOW WILL MOVE ONSHORE TUESDAY THEN WILL
BECOME BLOCKED BY AN AMPLIFIED RIDGE OVER THE MIDWEST. THIS COLD
LOW WILL RESULT IN UNSEASONABLY COLDER TEMPERATURES AND SHOWERY
CONDITIONS THROUGH THE EXTENDED PERIOD. SNOW LEVELS WILL LOWER
SIGNIFICANTLY LATE TUESDAY NIGHT AND WEDNESDAY MORNING...POSSIBLY AS
LOW AS 3500-4000 FEET. MODELS BEGIN TO DIVERGE ON THURSDAY. WHILE
THE ECMWF SWINGS THE LOW TO THE NORTHEAST ACROSS OREGON ON
FRIDAY...THE GFS IS FARTHER NORTH AND WEST WITH THE PRIMARY POSITION
OFFSHORE. AT THIS TIME...I`M LEANING TOWARDS THE ECMWF WHICH IS
CLOSER TO THE ENSEMBLE RUNS. EITHER WAY...THE PACIFIC NW WILL BE
COOL AND SHOWERY DURING THE LONG TERM PERIOD. WISTER
&&
.AVIATION...PREVIOUS DISCUSSION...18Z TAFS. SCATTERED SHOWERS MAY
BRIEFLY CAUSE CIGS TO LOWER TO NEAR MVFR THIS AFTERNOON AND
EVENING. OTHERWISE...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24
HOURS. CIGS WILL RANGE FROM 4-8000 FEET AGL...ALTHOUGH THERE WILL BE
BREAKS IN THE CLOUD COVER OVERNIGHT. SUSTAINED WINDS OF 10-20 KNOTS
CAN BE EXPECTED IN MOST AREAS. WISTER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 46 70 44 76 / 20 10 0 0
ALW 50 71 49 77 / 20 10 0 0
PSC 48 77 42 80 / 10 10 0 0
YKM 42 74 40 78 / 10 10 0 0
HRI 48 75 41 79 / 20 10 0 0
ELN 46 72 43 78 / 10 10 0 0
RDM 35 67 32 76 / 20 10 0 0
LGD 44 65 40 73 / 20 20 0 0
GCD 40 67 36 76 / 30 10 0 0
DLS 50 71 44 81 / 20 10 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SUNDAY : GREEN
MONDAY : GREEN
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
90/85/85
[top]
000
FXUS66 KPQR 182135
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
234 PM PDT SAT MAY 18 2013
.SYNOPSIS...PLENTY OF CLOUDS AND OCCASIONAL RAIN TODAY AS A WEAK LOW
PRESSURE SYSTEM SLOWLY MOVES INTO OREGON AND WASHINGTON. SHOWERS WILL
SLOWLY DECREASE TONIGHT AND SUNDAY AS THE SYSTEM MOVES INTO THE
GREAT BASIN AND FALLS APART. MORE SUNBREAKS SUNDAY SHOULD LEAD TO
MORE SEASONABLE TEMPERATURES. MONDAY IS SHAPING UP TO BE A PLEASANT
SUNNY AND WARM DAY UNDER HIGH PRESSURE WITH TEMPS IN THE LOWER TO MID
70S. HIGH CLOUDS WILL BEGIN TO INCREASE FROM THE NORTHWEST LATER IN
THE DAY IN ADVANCE OF OUR NEXT SYSTEM...WHICH WILL BRING A DRAMATIC
CHANGE BACK TO CHILLY AND UNSETTLED WEATHER TUESDAY THROUGH FRIDAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...VISIBLE SATELLITE IMAGERY
SHOWS SOLID CLOUD COVER ACROSS THE DISTRICT THIS AFTERNOON. KRTX
RADAR SHOWS AN AREA OF LIGHT RAIN SPREADING ACROSS WASHINGTON COUNTY
AND ENTERING THE GREATER PORTLAND AND EVENTUALLY VANCOUVER METRO
AREA. ADDITIONALLY AREAS OF LIGHT RAIN PERSIST ALONG THE COAST AND
MUCH OF THE REST OF OUR FORECAST AREA. SNOW LEVELS REMAIN RATHER
HIGH...ODOT PASS CAMS SHOW OCCASIONAL RAIN AND IT APPEARS TO BE
RAINING AT TIMBERLINE AS WELL.
WEAK AND POORLY DEFINED LOW PRESSURE CIRCULATION JUST OFFSHORE FROM
ASTORIA WILL DRAG A WEAK COLD FRONT ONSHORE OVER THE NEXT FEW HOURS
WITH DECREASING SHOWERS THEREAFTER. WHAT IS LEFT OF THE FRONT WILL
FINALLY LUMBER EAST ACROSS THE CASCADES TONIGHT WITH DECREASING
SHOWERS BEHIND THE FRONT. BY SUNDAY MORNING SHOWERS WILL BE MAINLY
CONFINED TO THE HIGHER TERRAIN...THOUGH A STRAY SHOWER IS STILL
POSSIBLE ELSEWHERE DUE TO WEAK SHALLOW INSTABILITY.
MADE VERY FEW CHANGES FOR MONDAY AND TUESDAY. THE MOVE THE MIDNIGHT
SHIFT MADE TO BUMP UP MONDAY TEMPS INTO THE 70S APPEARS TO BE A GOOD
ONE. THE AIR MASS LOOKS RATHER DRY THROUGHOUT MONDAY ON NAM BUFR
SOUNDINGS...FROM EUGENE ALL THE WAY UP TO PORTLAND. WITH 850 MB TEMPS
PUSHING +10 DEG C IN THE WILLAMETTE VALLEY...HIGHS COULD GET WELL
INTO THE 70S SOME AREAS WITH PLENTY OF SUNSHINE. ONSHORE GRADIENTS
WILL KEEP THE COAST FROM WARMING UP TOO MUCH.
MODELS SHOWING GOOD AGREEMENT ON RAIN FROM OUR NEXT SYSTEM HOLDING
OFF UNTIL TUESDAY MORNING. AS TUESDAY PROGRESSES IT APPEARS AN
UNSEASONABLY DEEP AND COLD UPPER LOW WILL SINK SOUTHEAST INTO WA/OR
SPREADING RAIN ACROSS THE REGION. RAIN APPEARS LIKELY A GOOD PORTION
OF THE DAY TUESDAY...WITH SNOW LEVELS LOWERING TO THE CASCADE PASSES
TUE NIGHT. THERE IS AN OUTSIDE CHANCE WE MAY NEED TO EVENTUALLY
CONSIDER SNOW ADVISORIES FOR THE CASCADES AS EARLY AS TUE NIGHT.
WEAGLE
.LONG TERM...TUESDAY EVENING THROUGH SATURDAY...FEW CHANGES. CLOSED
LOW PRESSURE SYSTEM WILL LINGER OVER THE PAC NW THROUGH THE WEEK.
WITH THE COLD NATURE OF THE LOW...RECORD LOW MAXIMUM TEMPERATURES
ARE POSSIBLE ON WEDNESDAY...WITH SNOW DOWN TO PASS LEVEL LIKELY IN
THE CASCADES. THURSDAY AND BEYOND MODELS BEGIN TO DISAGREE ON WHERE
THE LOW WILL PROPAGATE...HOWEVER THE OVERALL TREND WILL
REMAIN...WITH SHOWERY AND COOL CONDITIONS PERSISTING THROUGH AT
LEAST SATURDAY. BURGESS
&&
.AVIATION...MIX OF VFR AND MVFR CIGS ACROSS THE REGION. A
WEAKENING FRONT IS PUSHING ACROSS THE REGION...BUT BACK EDGE OF
THE FRONT IS STILL OFFSHORE AND NOT LIKELY TO CLEAR THE CASCADES
UNTIL THIS EVENING. NOT MUCH CHANGE...WITH SCATTERED SHOWERS AND
MOSTLY LOW VFR AND POCKETS OF MVFR THROUGH TONIGHT. CASCADES AND
PASSES WILL FREQUENTLY BE OBSCURED IN CLOUDS. SHOWERS SHOULD
DIMINISH OVERNIGHT BEHIND THE FRONT...WITH MVFR CIGS AT THE COAST
AND MOSTLY VFR INLAND. SOME PATCHY FOG POSSIBLE TOMORROW MORNING
IN THE SOUTHERN WILLAMETTE VALLEY IF ANY CLEARING
OCCURS...POSSIBLY AFFECTING KEUG.
KPDX AND APPROACHES...EXPECT A MIX OF VFR AND MVFR IN SCATTERED
SHOWERS THROUGH THIS AFTERNOON AS A COLD WORKS ITS WAY THROUGH.
SHOWER ACTIVITY SHOULD DECREASE LATER THIS EVENING BEHIND THE
FRONTAL PASSAGE. MOSTLY VFR CONDITIONS OVERNIGHT. PYLE
EXPECT LIGHT RAIN OR SHOWERS OFF AND ON THROUGH THE DAY.
PREDOMINANTLY VFR CONDITIONS MAY DROP TO MVFR AT TIMES DURING HEAVIER
SHOWERS. SHOWER ACTIVITY SHOULD TAPER OFF SOMEWHAT THIS EVENING...
WITH MAINLY VFR CONDITIONS DURING THE EVENING AND OVERNIGHT HOURS.
PYLE
&&
.MARINE...A COLD FRONT IS PUSHING THROUGH THE COASTAL WATERS THIS
AFTERNOON. THE FRONT HAS BEEN SLOWER THAN EXPECTED...SO DECIDED
TO EXTEND THE SMALL CRAFT ADVISORY FOR WINDS INTO THE EARLY
EVENING HRS. EXPECT WINDS TO DECREASE AND TURN NW LATER THIS
EVENING BEHIND THE FRONT. HIGH PRES WILL BUILD OVER THE NE PAC
SUN INTO EARLY NEXT WEEK. IT APPEARS THAT THERE WILL BE A FEW
CHANCES FOR SMALL CRAFT ADVISORIES FOR WINDS OVER THE NEXT FEW
DAYS. SUNDAY AND MONDAY MAY SEE WIND GUSTS INTO THE 20 TO 25 KT
RANGE DURING THE LATE AFTERNOON AND EARLY EVENING HRS.
SEAS REMAIN AT 5 TO 6 FT THROUGH THE WEEKEND. SEAS MAY BUMP UP A
BIT DURING THE PERIODS OF GUSTY WINDS ON SUN AND MON. A LARGE
LOW PRESSURE SYSTEM MAY BRING ANOTHER SMALL CRAFT FOR WINDS ON
WED...ALONG WITH SEAS ABOVE 10 FT. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 PM PDT THIS EVENING FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
&&
$$
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.
[top]
000
FXUS65 KBOI 182033
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
233 PM MDT SAT MAY 18 2013
.SHORT TERM...TONIGHT THROUGH MONDAY...A SHORT WAVE TROUGH MOVING
THROUGH THE BACK SIDE OF A DEPARTING LONG WAVE TROUGH WILL PASS
OVER THE AREA TONIGHT AND EARLY SUNDAY. THIS WILL INCREASE CLOUD
COVER AND SHOWERS AND BRING A RENEWED RISK OF THUNDERSTORMS THIS
EVENING. FOR SUNDAY...AS THE WAVE MOVES EAST...THE CHANCE OF
SHOWERS AND THREAT FOR THUNDERSTORMS WILL BE MAINLY IN SW IDAHO.
COOLER TEMPS WILL CONTINUE SUNDAY...WITH HIGHS AROUND 5 DEGREES
BELOW NORMAL. A SHORT-LIVED UPPER LEVEL RIDGE WILL MOVE QUICKLY
THROUGH MONDAY...BRINGING A WARM UP OF 5 TO 10 DEGREES AND A
GREATLY DECREASED CHANCE OF PRECIPITATION. WINDS THROUGH THE SHORT
TERM WILL BE LIGHT TO MODERATE. THE STRONGEST WINDS WILL BE SUNDAY
AFTERNOON WHEN GUSTS COULD REACH NEAR 30 MPH IN THE UPPER TREASURE
VALLEY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...THE BRIEF WARMING AND
DRYING TREND WILL CONTINUE TUESDAY WITH THE GREAT BASIN UNDER THE
INFLUENCE OF A SHORTWAVE RIDGE. TEMPERATURES ON TUESDAY ARE FORECAST
TO REACH 6-8 DEGREES F ABOVE NORMAL. HOWEVER THIS WILL NOT LAST LONG
AS A DEEP UPPER LEVEL LOW PRESSURE SYSTEM MOVING DOWN THE WASHINGTON
COASTLINE WILL BRING A STRONG COLD FRONT THROUGH THE AREA TUESDAY
NIGHT...DROPPING TEMPS BY AROUND 15 DEGREES FOR WEDNESDAY. THIS CUT
OFF LOW PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST WILL BE THE DOMINANT
FEATURE THROUGH THE REST OF THE FORECAST PERIOD. THE MODELS ARE
STRUGGLING TO PIN DOWN THE MOTION OF THE LOW THROUGH THE END OF THE WEEK
BUT THERE IS GOOD AGREEMENT THAT IT WILL BE STALLED OUT OVER THE PAC NW
THROUGH THE WEEKEND. THERE LOOKS TO BE AT LEAST A SLIGHT CHANCE OF SHOWERS
FROM WEDNESDAY ONWARDS...MAINLY OVER SE OREGON AND THE WEST CENTRAL IDAHO
MOUNTAINS. EXPECT TEMPERATURES TO BE SEVERAL DEGREES BELOW NORMAL FROM
THURSDAY AND BEYOND.
&&
.AVIATION...VFR UNDER BROKEN MID-LEVEL CLOUDS TODAY...EXCEPT FOR
OCCASIONAL MVFR CEILINGS AT KMYL THROUGH THIS EVENING. SCATTERED SHOWERS
AND THUNDERSTORM POSSIBLE AFTER 21Z...MAINLY ACROSS THE HIGHER TERRAIN OF
SE OREGON AND WEST CENTRAL IDAHO AND ALONG THE IDAHO/NEVADA BORDER. WNW
SURFACE WINDS WILL AVERAGE 10 TO 15 KTS WITH LOCAL GUSTS TO 25 KTS.
NORTHWESTERLY WINDS ALOFT WILL AVERAGE 15 KTS AT 10K FT MSL.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...SP
LONG TERM....CB/DD
AVIATION.....CB
000
FXUS66 KPDT 181731 AAA
AFDPDT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1035 AM PDT SAT MAY 18 2013
UPDATED AVIATION DISCUSSION
.SHORT TERM...UPDATE...A WEAK PACIFIC SYSTEM WILL MOVE ACROSS THE
REGION TODAY AND TONIGHT. WILL SEE CLOUDS INCREASE AND THICKEN
ACROSS THE AREA THIS MORNING INTO EARLY AFTERNOON. ALSO ISOLATED TO
SCATTERED SHOWERS WILL SPREAD ACROSS THE AREA, WITH THE BEST CHANCES
ACROSS CENTRAL AND EAST-CENTRAL OREGON. ALSO EXPECT SCATTERED
SHOWERS OVER THE MOUNTAINS WITH LOCALLY NUMEROUS SHOWERS ALONG THE
CASCADE CREST. MAY SEE ENOUGH INSTABILITY LATE THIS AFTERNOON INTO
EARLY THIS EVENING FOR STRAY THUNDERSTORMS OVER THE SOUTHERN OREGON
BLUE MOUNTAINS, THE JOHN DAY BASIN AND THE JOHN DAY-OCHOCO
HIGHLANDS. WINDS WILL BE BREEZY TO LOCALLY WINDY ACROSS THE AREA
THROUGH TODAY INTO THIS EVENING. UPDATES THIS MORNING INCLUDED
ADDING MENTION OF ISOLATED THUNDERSTORMS IN THE AREAS LISTED ABOVE,
AS WELL AS MAKING ADJUSTMENTS TO THE OTHER FORECAST PARAMETERS BASED
ON CURRENT TRENDS. 90
.LONG TERM...PREVIOUS DISCUSSION...MONDAY MORNING A LARGE MID/UPPER
LEVEL TROUGH MOVES SOUTHEAST ALONG THE SE ALASKAN ARCHIPELAGO AND
COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST NEAR 45N/135W IN
THE SOUTHERN JETSTREAM. DURING THE DAY ON MONDAY THESE TWO SYSTEMS
MERGE WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD INTO THE
EASTERN FLANK OF THE MID/UPPER TROUGH MOVING SOUTHEAST NEAR QUEEN
CHARLOTTE ISLAND.
TUESDAY THE LARGE UPPER TROUGH TRANSFORMS INTO A LARGE MID/UPPER
LEVEL LOW. THE LOW CONTINUES MOVING SOUTHEAST WITH THE CENTER OF THE
LOW APPROACHING THE COAST JUST WEST OF THE COLUMBIA RIVER BY LATE
TUESDAY AFTERNOON. THIS WILL CAUSE A SOUTHWEST FLOW ALOFT TO BACK
MORE TO THE SOUTH OVER THE FORECAST AREA AND TRANSPORT MOISTURE AND
INSTABILITY INTO THE REGION. THE COLD UPPER LOW WILL USHER IN A
COOLING TREND AND PERIODS OF UNSETTLED SHOWERY WEATHER, AS THE UPPER
LOW CENTER MOVES OVER THE FORECAST AREA AND PERSISTS THROUGH FRIDAY.
THE GFS AND ECMWF MODEL RUNS SHOW BETTER AGREEMENT FOR TUESDAY
THROUGH FRIDAY IN TERMS OF THE PLACEMENT OF THE UPPER LOW. DAYTIME
HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN NORMAL FOR TUESDAY
THROUGH FRIDAY.
TEMPERATURE LAPSE RATES FROM 5000 FT TO 20000 FT IN THE MID LEVELS
OF THE ATMOSPHERE OF SEVEN DEGREES CELSIUS OR LARGER SUGGEST THAT
THERE MAY BE ENOUGH MARGINAL INSTABILITY, COMBINED WITH VERY STRONG
DYNAMIC LIFT AND VERTICAL WIND SHEAR OF 40 TO 60 KNOTS FROM THE
SURFACE TO 20000 FT, WHICH WOULD FAVOR DEVELOPMENT OF A FEW ISOLATED
THUNDERSTORMS DURING THE DAYTIME ON WEDNESDAY, ESPECIALLY IN THE
AFTERNOON AND EARLY EVENING OVER THE MOUNTAINS. BUT WILL REFRAIN
FROM INTRODUCING A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY SINCE
THIS FAR OUT CONFIDENCE IS LOW WITH RESPECT TO AREAL COVERAGE OF
THUNDERSTORM POTENTIAL.
&&
.AVIATION...18Z TAFS. SCATTERED SHOWERS MAY BRIEFLY CAUSE CIGS TO
LOWER TO NEAR MVFR THIS AFTERNOON AND EVENING. OTHERWISE...VFR
CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. CIGS WILL RANGE FROM
4-8000 FEET AGL...ALTHOUGH THERE WILL BE BREAKS IN THE CLOUD COVER
OVERNIGHT. SUSTAINED WINDS OF 10-20 KNOTS CAN BE EXPECTED IN MOST
AREAS. WISTER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 66 45 68 42 / 20 20 10 0
ALW 69 51 69 46 / 20 20 10 0
PSC 74 50 74 44 / 20 10 10 0
YKM 70 48 72 45 / 20 10 10 0
HRI 72 49 72 43 / 20 20 10 0
ELN 68 47 69 42 / 20 10 10 0
RDM 63 35 63 29 / 30 20 10 0
LGD 62 45 62 39 / 20 20 20 0
GCD 65 43 63 38 / 30 30 10 10
DLS 68 50 68 44 / 20 20 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
90/99/85
000
FXUS66 KPDT 181637
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
935 AM PDT SAT MAY 18 2013
.SHORT TERM...UPDATE...A WEAK PACIFIC SYSTEM WILL MOVE ACROSS THE
REGION TODAY AND TONIGHT. WILL SEE CLOUDS INCREASE AND THICKEN
ACROSS THE AREA THIS MORNING INTO EARLY AFTERNOON. ALSO ISOLATED TO
SCATTERED SHOWERS WILL SPREAD ACROSS THE AREA, WITH THE BEST CHANCES
ACROSS CENTRAL AND EAST-CENTRAL OREGON. ALSO EXPECT SCATTERED
SHOWERS OVER THE MOUNTAINS WITH LOCALLY NUMEROUS SHOWERS ALONG THE
CASCADE CREST. MAY SEE ENOUGH INSTABILITY LATE THIS AFTERNOON INTO
EARLY THIS EVENING FOR STRAY THUNDERSTORMS OVER THE SOUTHERN OREGON
BLUE MOUNTAINS, THE JOHN DAY BASIN AND THE JOHN DAY-OCHOCO
HIGHLANDS. WINDS WILL BE BREEZY TO LOCALLY WINDY ACROSS THE AREA
THROUGH TODAY INTO THIS EVENING. UPDATES THIS MORNING INCLUDED
ADDING MENTION OF ISOLATED THUNDERSTORMS IN THE AREAS LISTED ABOVE,
AS WELL AS MAKING ADJUSTMENTS TO THE OTHER FORECAST PARAMETERS BASED
ON CURRENT TRENDS. 90
.LONG TERM...PREVIOUS DISCUSSION...MONDAY MORNING A LARGE MID/UPPER
LEVEL TROUGH MOVES SOUTHEAST ALONG THE SE ALASKAN ARCHIPELAGO AND
COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST NEAR 45N/135W IN
THE SOUTHERN JETSTREAM. DURING THE DAY ON MONDAY THESE TWO SYSTEMS
MERGE WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD INTO THE
EASTERN FLANK OF THE MID/UPPER TROUGH MOVING SOUTHEAST NEAR QUEEN
CHARLOTTE ISLAND.
TUESDAY THE LARGE UPPER TROUGH TRANSFORMS INTO A LARGE MID/UPPER
LEVEL LOW. THE LOW CONTINUES MOVING SOUTHEAST WITH THE CENTER OF THE
LOW APPROACHING THE COAST JUST WEST OF THE COLUMBIA RIVER BY LATE
TUESDAY AFTERNOON. THIS WILL CAUSE A SOUTHWEST FLOW ALOFT TO BACK
MORE TO THE SOUTH OVER THE FORECAST AREA AND TRANSPORT MOISTURE AND
INSTABILITY INTO THE REGION. THE COLD UPPER LOW WILL USHER IN A
COOLING TREND AND PERIODS OF UNSETTLED SHOWERY WEATHER, AS THE UPPER
LOW CENTER MOVES OVER THE FORECAST AREA AND PERSISTS THROUGH FRIDAY.
THE GFS AND ECMWF MODEL RUNS SHOW BETTER AGREEMENT FOR TUESDAY
THROUGH FRIDAY IN TERMS OF THE PLACEMENT OF THE UPPER LOW. DAYTIME
HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN NORMAL FOR TUESDAY
THROUGH FRIDAY.
TEMPERATURE LAPSE RATES FROM 5000 FT TO 20000 FT IN THE MID LEVELS
OF THE ATMOSPHERE OF SEVEN DEGREES CELSIUS OR LARGER SUGGEST THAT
THERE MAY BE ENOUGH MARGINAL INSTABILITY, COMBINED WITH VERY STRONG
DYNAMIC LIFT AND VERTICAL WIND SHEAR OF 40 TO 60 KNOTS FROM THE
SURFACE TO 20000 FT, WHICH WOULD FAVOR DEVELOPMENT OF A FEW ISOLATED
THUNDERSTORMS DURING THE DAYTIME ON WEDNESDAY, ESPECIALLY IN THE
AFTERNOON AND EARLY EVENING OVER THE MOUNTAINS. BUT WILL REFRAIN
FROM INTRODUCING A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY SINCE
THIS FAR OUT CONFIDENCE IS LOW WITH RESPECT TO AREAL COVERAGE OF
THUNDERSTORM POTENTIAL.
&&
.AVIATION...PREVIOUS DISCUSSION...12Z TAFS...VFR CONDITIONS ARE
EXPECTED OVER THE NEXT 24 HOURS. THERE MAY BE BRIEF MVFR CONDITIONS
AT KRDM AND KBDN DUE TO SHOWERS AFTER 18Z. OTHERWISE, CIGS WILL BE
SCT TO BKN 5000 FT AND BKN TO OVC 10000 FT THROUGH 03Z/19TH WITH
CONDITIONS GRADUALLY IMPROVING. WINDS WILL BE BETWEEN 5-15 KTS
GUSTING TO 25 KTS AT TIMES IN THE AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 66 45 68 42 / 20 20 10 0
ALW 69 51 69 46 / 20 20 10 0
PSC 74 50 74 44 / 20 10 10 0
YKM 70 48 72 45 / 20 10 10 0
HRI 72 49 72 43 / 20 20 10 0
ELN 68 47 69 42 / 20 10 10 0
RDM 63 35 63 29 / 30 20 10 0
LGD 62 45 62 39 / 20 20 20 0
GCD 65 43 63 38 / 30 30 10 10
DLS 68 50 68 44 / 20 20 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
90/99/85
000
FXUS66 KPQR 181609
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
908 AM PDT SAT MAY 18 2013
.SYNOPSIS...A WEAK FRONTAL SYSTEM IS SPREADING LIGHT RAIN ACROSS
FORECAST AREA THIS MORNING. OCCASIONAL RAIN WILL CONTINUE THROUGH THE
DAY WITH CLOUDY SKIES AND TEMPS STUCK AROUND 60 DEGREES FOR THE
LOWLANDS. SNOW LEVELS WILL REMAIN WELL ABOVE THE PASSES. SHOWERS WILL
GRADUALLY DECREASE TONIGHT AND SUNDAY AS THE SYSTEM MOVES INTO THE
GREAT BASIN AND HIGH PRESSURE BEGINS TO BUILD. THIS HIGH PRESSURE
SHOULD RESULT IN DRIER AND WARMER CONDITIONS SUN NIGHT INTO MON.
HOWEVER IT APPEARS LIKELY AN UNSEASONABLY COLD UPPER LOW WILL BRING
COOL AND UNSETTLED WEATHER TUESDAY THROUGH FRIDAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...LATEST RADAR IMAGERY AND
SURFACE OBSERVATIONS SHOW LIGHT RAIN SPREADING ACROSS THE PORTLAND
AND VANCOUVER METRO THIS MORNING...MOVING EAST INTO THE CASCADES. A
WEAK FRONTAL SYSTEM MOVING ONSHORE IS RESPONSIBLE FOR THIS...WITH THE
FIRST BAND OF RAIN ASSOCIATED WITH WEAK ISENTROPIC LIFT.
LATEST MSAS SFC PRESSURE ANALYSIS SHOWS AN ELONGATED LOW PRESSURE
TROUGH JUST OFFSHORE...WHICH SEEMS TO MATCH VISIBLE IMAGERY FAIRLY
WELL. LOOPING THIS IMAGERY SEEMS TO SHOW A VERY FAINT CIRCULATION IN
THE LOW CLOUDS CENTERED NEAR 46N/126W...MOVING NORTHEAST. THIS WEAK
LOW WILL LIKELY DRAG A WEAK COLD FRONT ACROSS THE DISTRICT THIS
AFTERNOON...SPREADING ANOTHER BATCH OF RAIN ACROSS THE FORECAST AREA.
OVERALL RAINFALL AMOUNTS TODAY THROUGH THIS EVENING WILL PROBABLY BE
0.10-0.20 INCH IN THE VALLEYS...UP TO 0.50-0.75 INCH IN THE HIGHER
TERRAIN. EXPECT LITTLE TO NO BREAKS IN THE CLOUDS TODAY WITH THE VERY
MOIST AIR MASS...TEMPS WILL STRUGGLE TO REACH 60 DEGREES AND MOS
GUIDANCE APPEARS TO BE CATCHING ON TO THIS CONCEPT.
THERE WILL BE MORE BREAKS IN THE CLOUDS SUNDAY AS HIGH PRESSURE
BEGINS TO BUILD INTO THE REGION. SOME WEAK AND SHALLOW INSTABILITY
LEFT BEHIND BY ALLOW AN ISOLATED SHOWER OR TWO...WITH THE BEST CHANCE
OVER THE HIGHER TERRAIN. THE AIR MASS WILL BE RAPIDLY WARMING
ALOFT...CAPPING THE INSTABILITY AND KEEPING IT TOO SHALLOW FOR TSTMS
SUNDAY DESPITE THE WARMER SFC TEMPS IN THE MID TO UPPER 60S. WEAGLE
REMAINDER OF FCST DISCUSSION UNCHANGED FROM PREVIOUS SHIFT...HIGH
PRESSURE MAINTAIN DRY WEATHER FOR MONDAY WHICH WILL LIKELY BE
THE WARMEST DAY OF THE WEEK. INCREASED SUNSHINE SHOULD WARM INTERIOR
TEMPERATURES TO SLIGHTLY ABOVE NORMAL...LOW 70S AND COASTAL AREAS TO
NEAR NORMAL...LOWER 60S. AN UPPER LEVEL LOW WILL APPROACH MONDAY
NIGHT AND BRING A RETURN OF SHOWERS AND MUCH COOLER WEATHER TO THE
REGION. MODELS HAVE BACKED OFF THE TIMING OF THE ONSET OF RAIN AROUND
12 HOURS. THE COLDEST AIR ASSOCIATED WITH THE LOW WILL BEGIN MOVING
OVER THE AREA TUESDAY NIGHT AND SNOW LEVELS SHOULD LOWER TO AROUND
3500 TO 4000 FEET.
.LONG TERM...WEDNESDAY THROUGH FRIDAY...A COLD CLOSED LOW WILL
CONTINUE UNSETTLED WEATHER WITH UNSEASONAL COLD TEMPERATURES
WEDNESDAY...WITH RECORD LOW MAXIMUM TEMPERATURES POSSIBLE. WEDNESDAY
WILL BE THE COLDEST DAY OF THE WORK WEEK. TEMPERATURES WILL REMAIN
BELOW THE SEASONAL NORMALS THURSDAY AND FRIDAY AS A COUPLE OF
SHORTWAVE TROUGHS WILL CONTINUE SHOWERY AND COOL CONDITIONS.
&&
.AVIATION...A FRONTAL BOUNDARY MOVING THROUGH THE REGION WILL
BRING PERIODS OF LIGHT RAIN OR SHOWERS THROUGH MUCH OF THE DAY.
EXPECT A MIX OF VFR AND MVFR CONDITIONS...WITH THE PERIODS OF MVFR
COINCIDING WITH THE HEAVIER SHOWERS. EXPECT SHOWER ACTIVITY TO
CONTINUE BUT BECOME MORE SCATTERED THIS EVENING BEHIND THE FRONTAL
PASSAGE. EXPECT MAINLY VFR CONDITIONS THIS EVENING...WITH MVFR
CIGS PUSHING INTO THE COAST OVERNIGHT.
KPDX AND APPROACHES...EXPECT LIGHT RAIN OR SHOWERS OFF AND ON
THROUGH THE DAY. PREDOMINANTLY VFR CONDITIONS MAY DROP TO MVFR AT
TIMES DURING HEAVIER SHOWERS. SHOWER ACTIVITY SHOULD TAPER OFF
SOMEWHAT THIS EVENING...WITH MAINLY VFR CONDITIONS DURING THE
EVENING AND OVERNIGHT HOURS. PYLE
&&
.MARINE...A FRONT WILL PUSH ACROSS THE COASTAL WATERS THIS
MORNING...THEN INLAND EARLY THIS AFTERNOON. NOT A LOT OF WIND
CURRENTLY BEING OBSERVED...BUT EXPECT THAT WINDS WILL PICK UP A
BIT LATER THIS MORNING AS THE COLD FRONT COMES THROUGH. THERE
SEEMS SO BE ENOUGH GRADIENT TO POP GUSTS 20 TO 25 KT RIGHT AHEAD
OF THE FRONT. SO WILL MAINTAIN CURRENT SMALL CRAFT ADVISORY.
OTHERWISE...WINDS TURN W TO NW BEHIND THE FRONT IN THE AFTERNOON
AND BEGIN TO EASE.
HIGH PRES WILL BUILD OVER THE NE PAC SUN INTO EARLY NEXT WEEK.
THIS WILL KEEP NW WINDS 10 TO 15 KT THROUGH MUCH OF THE COMING
WEEK...THOUGH MAY BRIEFLY GET 20 TO 25 KT GUSTS MON AFTERNOON INTO
THE EVENING.
SEAS REMAIN AT 5 TO 6 FT FOR INTO EARLY NEXT WEEK. MAY SEE SEAS
BUILD UP AND BECOME CHOPPY AT TIMES WITH THE BRISK NW WINDS ON THE
CENTRAL OREGON COASTAL WATERS NEXT WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 PM PDT THIS AFTERNOON FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
&&
$$
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.
000
FXUS65 KBOI 181558
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
958 AM MDT SAT MAY 18 2013
.DISCUSSION...ONE WEAK SHORT WAVE TROUGH IS DEPARTING THE AREA
THIS MORNING WHILE ANOTHER STRONGER WAVE IS APPROACHING FOR
TONIGHT. THE SPACE IN BETWEEN WILL BE A RELATIVE LULL IN
CONVECTIVE ACTIVITY...AND THAT IS FORECAST TO BE OVER OUR AREA
THIS AFTERNOON. WE EXPECT SIGNIFICANTLY FEWER SHOWERS AND STORMS
THAN YDAY. THIS IS ALREADY IN THE FORECAST AND NO CHANGES ARE
PLANNED AT THIS TIME.
&&
.AVIATION...VFR UNDER SCATTERED MID-LEVEL CLOUDS TODAY...EXCEPT FOR
MVFR CEILINGS AT KMYL THROUGH 18Z. SCATTERED SHOWERS AND THUNDERSTORMS
POSSIBLE AFTER 21Z...MAINLY ACROSS THE HIGHER TERRAIN OF SE OREGON AND
WEST CENTRAL IDAHO AND ALONG THE IDAHO/NEVADA BORDER. W/NW SURFACE WINDS
WILL AVERAGE 10 TO 15 KTS WITH LOCAL GUSTS TO 25 KTS. NORTHWESTERLY WINDS
ALOFT WILL AVERAGE 15 KTS AT 10K FT MSL.
&&
.PREV DISCUSSION...
SHORT TERM...ONE UPPER TROUGH EXITING EAST THIS MORNING AS ANOTHER
TROUGH COMES IN FROM THE NORTHWEST AND FORMS A WEAK CLOSED LOW OVER
OUR CWA TONIGHT. THESE TROUGHS WILL KEEP MAX TEMPS BELOW NORMAL
THIS WEEKEND. OUR FORECAST MAX TEMPS ARE CLOSER TO THE COOLER MET
MOS THAN THE MAV MOS BOTH TODAY AND SUNDAY. MIN TEMPS TONIGHT ARE
CLOSE TO MAV AND MET MOS WHICH ARE RELATIVELY CLOSE TO EACH OTHER.
SCATTERED SHOWERS WILL CONTINUE IN HIGHER TERRAIN....SNOW ON HIGHEST
PEAKS. ONLY ISOLATED SHOWERS AT MOST AT LOWER ELEVATIONS INCLUDING
THE SNAKE BASIN. AIR MASS MARGINALLY UNSTABLE THIS AFTERNOON AND
EARLY EVENING WITH ISOLATED THUNDERSTORMS AGAIN IN HIGHER TERRAIN
IN BOTH OREGON AND IDAHO...BUT ONLY ON THE IDAHO SIDE SUNDAY
AFTERNOON. BREEZY WINDS THIS AFTERNOON IN THE SNAKE BASIN AND IN
EASTERN OREGON. SUNDAY AFTERNOON WILL BE WINDIER ESPECIALLY IN THE
SNAKE BASIN AS NORTHWEST WINDS ALOFT ALIGN WITH PRESSURE GRADIENT AT
THE SURFACE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY...WARMER AND
SIGNIFICANTLY DRIER SUNDAY NIGHT THROUGH EARLY TUESDAY AS A SHORT
WAVE RIDGE MOVES OVER THE GREAT BASIN. RIDGE WILL BE FORCED
EASTWARD TUESDAY EVENING...AS A DEEP UPPER LEVEL LOW MOVES SOUTH
ALONG THE PACIFIC NORTHWEST COAST. ASSOCIATED COLD FRONT WILL CROSS
SE OREGON AND SW IDAHO TUESDAY NIGHT. EXPECT INCREASED WINDS...A
CHANCE OF PRECIPITATION...AND A DRAMATIC DROP IN TEMPERATURES /FROM
TUESDAY/ BY WEDNESDAY AFTERNOON. UPPER LOW WILL HOLD STRONG OVER THE
PACIFIC NORTHWEST THROUGH THE EXTENDED PERIOD WARRANTING A FORECAST
OF BELOW NORMAL TEMPERATURES AND PERIODS OF PRECIPITATION THURSDAY
THROUGH SUNDAY.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...SP
AVIATION.....CB
PREV SHORT TERM...LC
PREV LONG TERM....MT
000
FXUS66 KMFR 181518
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
820 AM PDT SAT MAY 18 2013
.DISCUSSION...BANDS OF SHOWERS ARE MOVING THROUGH THE REGION THIS
MORNING WITH MODELS INDICATING THAT THEY WILL BECOME MORE WIDESPREAD
LATER THROUGH THE DAY AS LAPSE RATES INCREASE THROUGH THE DAY AND
FLOW BECOMES ONSHORE. CURRENT FORECAST LOOKS ON TRACK AND WILL NOT
UPDATE THIS MORNING.
PREVIOUS DISCUSSION...A MID LEVEL TROUGH AXIS AND ASSOCIATED TROUGH
AXIS WILL PASS OVER THE FORECAST AREA TODAY...AND WILL RESULT IN RAIN
OVER MUCH OF THE AREA. LOCATIONS ALONG THE COAST...THE UMPQUA
BASIN...AND ALONG THE CASCADES WILL BE THE MAJOR FOCUS OF PRECIP
TODAY...BUT THERE IS A CHANCE OF RAIN OVER VIRTUALLY ALL PARTS OF
THE CWA THROUGH THIS EVENING. HAVE DEBATED ON THE POSSIBILITY OF
THUNDER OVER MY FAR EASTERN ZONES LATE THIS MORNING AND EARLY THIS
AFTERNOON. THE GFS AND NAM BOTH DEPICT SOME WEAK INSTABILITY...AS
WELL AS LIFTED INDICES OF -2 AND A WIDE AREA OF POTENTIAL LIFT.
HAVE THEREFORE INCREASED IN COVERAGE THE SLIGHT CHANCE OF THUNDER
OVER PORTIONS OF LAKE AND MODOC COUNTIES THAT WAS INTRODUCED BY
EARLIER SHIFTS. OVERALL...PRECIPITATION WILL DECREASE IN COVERAGE
OVERNIGHT...BUT SHOWERS COULD LINGER OVER THE CASCADES AND THE
UMPQUA BASIN THROUGH EARLY SUNDAY MORNING.
ONCE THE TROUGH EXITS THE AREA SUNDAY MORNING...RIDGING WILL
BUILD UP THE COAST AND INTO THE PACIFIC NORTHWEST. THE THERMAL
TROUGH WILL RETURN DURING THIS TIME...AND THE USUAL CONDITIONS
EXPECTED WITH THE FEATURE WILL RETURN. DRY OFFSHORE FLOW WILL
PREVAIL...AND WARMER THAN NORMAL TEMPERATURES ARE EXPECTED UNDER
MOSTLY CLEAR SKIES...WHILE WINDS ALONG THE COAST AND ACROSS HIGHER
TERRAIN WILL BE GUSTY. THERE IS ALSO A HIGH LIKELIHOOD OF THE
CHETCO EFFECT TO DEVELOP SUNDAY AND MONDAY...THUS HIGHER THAN
NORMAL TEMPERATURES ALONG THE SOUTHWESTERN COAST OF OREGON ARE
EXPECTED.
THE RIDGE AND THERMAL TROUGH WILL BE SHORT LIVED...AS A POTENT CUT
OFF LOW WILL DESCEND SOUTHWARD FROM THE GULF OF ALASKA TOWARDS THE
PACIFIC NORTHWEST BEGINNING MONDAY NIGHT. THE LOW IS EXPECTED TO
TAKE UP STATION DIRECTLY OVER OREGON AND WASHINGTON BY TUESDAY
NIGHT...AND REMAIN IN THE AREA FOR SEVERAL DAYS. MODEL SOLUTIONS
DEPICT THE LOW WOBBLING AROUND THE AREA AS MULTIPLE SHORTWAVES
ORBIT AROUND IT. THE 12Z ECMWF RUN PRODUCED A SMALL KICKER LOW
THAT SHUNTS THE CLOSED LOW OUT OF THE AREA MUCH SOONER...BUT HAS
RETURNED TO A MORE LONG LIVED EVENT WITH THE 00Z RUN. IT IS
BELIEVED THAT THE MODELS WILL HAVE A DIFFICULT TIME RESOLVING THE
BEHAVIOR OF THE SYSTEM...DUE TO THE INHERENT DIFFICULTIES THEY
TEND TO HAVE WITH CUT OFF LOWS...AND DUE TO THE POSSIBILITY OF A
BLOCKING RIDGE DEVELOPING OVER CENTRAL NORTH AMERICA...WHICH BOTH
THE GFS AND ECMWF HAVE DEPICTED IN SEVERAL RUNS. THIS INTRODUCES
QUITE A BIT OF UNCERTAINTY TO THE FORECAST...BUT THERE IS A GREAT
DEAL OF CONFIDENCE IN THE OVERALL PATTERN THAT CAN BE
EXPECTED...ONE OF COOLER THAN NORMAL TEMPERATURES AND A GOOD
CHANCE FOR MULTIPLE PERIODS OF RAIN. THE DAY TO DAY POPS WILL
DEPEND A GREAT DEAL ON THE WOBBLE OF THE LOW...THE INDIVIDUAL
TIMING AND STRENGTHS OF THE ORBITING SHORTWAVES...AND THE
AVAILABILITY OF MOISTURE. HAVE THEREFORE KEPT POPS ABOVE CLIMO AND
TEMPERATURES BELOW NORMAL FOR THE DURATION OF THE EXTENDED TERM.
THAT BEING SAID...THERE IS A POTENTIAL FOR LATE MAY SNOWFALL OVER
THE CASCADES...PORTIONS OF THE EAST SIDE...AND EVEN SOME OF THE
PASSES...AS SNOW LEVELS COULD EASILY DROP TO BELOW 4000 FEET. ALL
OF THESE DETAILS WILL SLOWLY COME INTO FOCUS DURING THE NEXT FEW
FORECAST CYCLES...BUT FOR NOW...ANYONE WITH OUTDOOR INTERESTS
DURING THE MEMORIAL DAY WEEKEND SHOULD BE PREPARED TO CONTEND WITH
COLD AND WET WEATHER...AND EVEN SOME SNOW IN THE HIGHER
ELEVATIONS.
&&
.AVIATION...BASED ON THE 18/06Z TAF CYCLE.
CEILINGS WILL LOWER TO MVFR THIS MORNING ALONG THE COAST AND IN THE
UMPQUA VALLEY AS A COLD FRONT MOVES IN. TERRAIN OBSCURATION WILL BE
PREVALENT ALONG AND WEST OF THE CASCADES. THERE WILL ALSO BE AREAS
OF LIGHT RAIN ALONG THE FRONT THIS MORNING TAPERING OFF TO SHOWERS
BEHIND IT THIS AFTERNOON. MOSTLY VFR IS EXPECTED AT KMFR, BUT
CEILINGS MAY BRIEFLY LOWER TO NEAR MVFR WITH A SHOWER IN THE
VICINITY THIS AFTERNOON. EAST OF THE CASCADES, EXPECT MOSTLY VFR
THOUGH CIGS MAY ALSO BRIEFLY LOWER TO MVFR IN AND NEAR ANY SHOWERS.
GUSTY WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS AFTERNOON/EARLY
THIS EVENING WITH GUSTS JUST SHY OF 30KT AT KLMT. THUNDER POTENTIAL
IS SLIM AND WILL LIKELY BE RESTRICTED TO AREAS ALONG AND EAST OF THE
WARNER MOUNTAINS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...GALE WATCH FROM SUNDAY AFTERNOON THROUGH
MONDAY EVENING FOR
PZZ376.
HAZARDOUS SEAS WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR PZZ376.
$$
BPN/MAS
000
FXUS66 KPDT 181051 AAA
AFDPDT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
351 AM PDT SAT MAY 18 2013
UPDATED AVIATION AND LONG TERM DISCUSSIONS
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT...ONE WAVE IS MOVING
THROUGH WALLOWA COUNTY AND THE NORTHERN BLUES THIS MORNING WHILE
ANOTHER ONE IS APPROACHING THE COAST. 6Z NAM INDICATES THE FIRST
WAVE WILL BE OUT OF THE CWA BY 12Z..BUT SOME OF THE SHOWERS MAY
LINGER INTO THE MORNING FORECAST TIME. I MIGHT MAKE A LATE
ADJUSTMENT BASED ON LATEST RADAR. CURRENT RADAR INDICATES THAT
PRECIPITATION AHEAD OF THE SECOND WAVE IS APPROACHING THE
CASCADES..SO THERE WILL BE SOME SLOP OVER MORNING PRECIPITATION
THERE AS WELL. ISOLATED TO SCATTERED SHOWERS WILL DEVELOP WITH
DAYTIME HEATING AGAIN THIS AFTERNOON ACROSS SOUTHEAST WASHINGTON AND
EASTERN OREGON. INSTABILITY INDICATED BY NEGATIVE LIS AND MUCAPE IS
MAINLY SOUTH OF THE CWA SO I DID NOT INCLUDE ANY THUNDERSTORMS IN
THE FORECAST THIS AFTERNOON. THE SECOND WAVE WILL MOVE EAST OF THE
CASCADES EARLY THIS EVENING. THERE WILL BE SOME CLEARING BEHIND THIS
WAVE IN THE WESTERN HALF OF THE CWA OVERNIGHT...BUT SHOWERS WILL
PERSIST FROM GRANT COUNTY TO THE NORTHERN BLUES AND WALLOWA COUNTY
OVERNIGHT DUE TO THIS WAVE. AN UPPER LEVEL RIDGE WILL BUILD ALONG
THE COAST SUNDAY. THIS WILL BRING A DRIER NORTHWEST FLOW TO EASTERN
WASHINGTON AND OREGON. ENOUGH MOISTURE MAY LINGER FROM GRANT COUNTY
TO THE NORTHERN BLUES AND WALLOWA COUNTY FOR A FEW SHOWERS TO
DEVELOP WITH AFTERNOON HEATING. THE RIDGE AXIS WILL MOVE INTO
EASTERN WASHINGTON AND OREGON SUNDAY NIGHT WITH CLEARING SKIES. THIS
WILL ALLOW RADIATIONAL COOLING WITH COOLER OVERNIGHT TEMPERATURES.
COONFIELD
.LONG TERM...MONDAY THROUGH FRIDAY...MONDAY MORNING A LARGE
MID/UPPER LEVEL TROUGH MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/135W IN THE SOUTHERN JETSTREAM. DURING THE DAY ON MONDAY
THESE TWO SYSTEMS MERGE WITH THE SOUTHERN SYSTEM PULLING MOISTURE
NORTHWARD INTO THE EASTERN FLANK OF THE MID/UPPER TROUGH MOVING
SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
TUESDAY THE LARGE UPPER TROUGH TRANSFORMS INTO A LARGE MID/UPPER
LEVEL LOW. THE LOW CONTINUES MOVING SOUTHEAST WITH THE CENTER OF THE
LOW APPROACHING THE COAST JUST WEST OF THE COLUMBIA RIVER BY LATE
TUESDAY AFTERNOON. THIS WILL CAUSE A SOUTHWEST FLOW ALOFT TO BACK
MORE TO THE SOUTH OVER THE FORECAST AREA AND TRANSPORT MOISTURE AND
INSTABILITY INTO THE REGION. THE COLD UPPER LOW WILL USHER IN A
COOLING TREND AND PERIODS OF UNSETTLED SHOWERY WEATHER, AS THE UPPER
LOW CENTER MOVES OVER THE FORECAST AREA AND PERSISTS THROUGH FRIDAY.
THE GFS AND ECMWF MODEL RUNS SHOW BETTER AGREEMENT FOR TUESDAY
THROUGH FRIDAY IN TERMS OF THE PLACEMENT OF THE UPPER LOW. DAYTIME
HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN NORMAL FOR TUESDAY
THROUGH FRIDAY.
TEMPERATURE LAPSE RATES FROM 5000 FT TO 20000 FT IN THE MID LEVELS
OF THE ATMOSPHERE OF SEVEN DEGREES CELSIUS OR LARGER SUGGEST THAT
THERE MAY BE ENOUGH MARGINAL INSTABILITY, COMBINED WITH VERY STRONG
DYNAMIC LIFT AND VERTICAL WIND SHEAR OF 40 TO 60 KNOTS FROM THE
SURFACE TO 20000 FT, WHICH WOULD FAVOR DEVELOPMENT OF A FEW ISOLATED
THUNDERSTORMS DURING THE DAYTIME ON WEDNESDAY, ESPECIALLY IN THE
AFTERNOON AND EARLY EVENING OVER THE MOUNTAINS. BUT WILL REFRAIN
FROM INTRODUCING A SLIGHT CHANCE OF THUNDERSTORMS ON WEDNESDAY SINCE
THIS FAR OUT CONFIDENCE IS LOW WITH RESPECT TO AREAL COVERAGE OF
THUNDERSTORM POTENTIAL. POLAN
&&
.AVIATION...12Z TAFS...VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24
HOURS. THERE MAY BE BRIEF MVFR CONDITIONS AT KRDM AND KBDN DUE TO
SHOWERS AFTER 18Z. OTHERWISE, CIGS WILL BE SCT TO BKN 5000 FT AND
BKN TO OVC 10000 FT THROUGH 03Z/19TH WITH CONDITIONS GRADUALLY
IMPROVING. WINDS WILL BE BETWEEN 5-15 KTS GUSTING TO 25 KTS AT TIMES
IN THE AFTERNOON. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 66 45 68 42 / 20 20 10 0
ALW 69 51 69 46 / 20 20 10 0
PSC 74 50 74 44 / 20 10 10 0
YKM 70 48 72 45 / 20 10 10 0
HRI 72 49 72 43 / 20 10 10 0
ELN 68 47 69 42 / 20 10 10 0
RDM 63 35 63 29 / 30 20 10 0
LGD 62 45 62 39 / 20 20 20 0
GCD 62 43 63 38 / 30 20 10 10
DLS 66 50 68 44 / 20 20 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
76/99/99
000
FXUS66 KPDT 181004
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
304 AM PDT SAT MAY 18 2013
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT...ONE WAVE IS MOVING
THROUGH WALLOWA COUNTY AND THE NORTHERN BLUES THIS MORNING WHILE
ANOTHER ONE IS APPROACHING THE COAST. 6Z NAM INDICATES THE FIRST
WAVE WILL BE OUT OF THE CWA BY 12Z..BUT SOME OF THE SHOWERS MAY
LINGER INTO THE MORNING FORECAST TIME. I MIGHT MAKE A LATE
ADJUSTMENT BASED ON LATEST RADAR. CURRENT RADAR INDICATES THAT
PRECIPITATION AHEAD OF THE SECOND WAVE IS APPROACHING THE
CASCADES..SO THERE WILL BE SOME SLOP OVER MORNING PRECIPITATION
THERE AS WELL. ISOLATED TO SCATTERED SHOWERS WILL DEVELOP WITH
DAYTIME HEATING AGAIN THIS AFTERNOON ACROSS SOUTHEAST WASHINGTON AND
EASTERN OREGON. INSTABILITY INDICATED BY NEGATIVE LIS AND MUCAPE IS
MAINLY SOUTH OF THE CWA SO I DID NOT INCLUDE ANY THUNDERSTORMS IN
THE FORECAST THIS AFTERNOON. THE SECOND WAVE WILL MOVE EAST OF THE
CASCADES EARLY THIS EVENING. THERE WILL BE SOME CLEARING BEHIND THIS
WAVE IN THE WESTERN HALF OF THE CWA OVERNIGHT...BUT SHOWERS WILL
PERSIST FROM GRANT COUNTY TO THE NORTHERN BLUES AND WALLOWA COUNTY
OVERNIGHT DUE TO THIS WAVE. AN UPPER LEVEL RIDGE WILL BUILD ALONG
THE COAST SUNDAY. THIS WILL BRING A DRIER NORTHWEST FLOW TO EASTERN
WASHINGTON AND OREGON. ENOUGH MOISTURE MAY LINGER FROM GRANT COUNTY
TO THE NORTHERN BLUES AND WALLOWA COUNTY FOR A FEW SHOWERS TO
DEVELOP WITH AFTERNOON HEATING. THE RIDGE AXIS WILL MOVE INTO
EASTERN WASHINGTON AND OREGON SUNDAY NIGHT WITH CLEARING SKIES. THIS
WILL ALLOW RADIATIONAL COOLING WITH COOLER OVERNIGHT TEMPERATURES.
COONFIELD
.LONG TERM...MONDAY THROUGH FRIDAY...MONDAY MORNING A LARGE
MID/UPPER LEVEL TROUGH MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/135W IN THE SOUTHERN JETSTREAM. DURING THE DAY ON MONDAY
THESE TWO SYSTEMS MERGE WITH THE SOUTHERN SYSTEM PULLING MOISTURE
NORTHWARD INTO THE EASTERN FLANK OF THE MID/UPPER TROUGH MOVING
SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
TUESDAY THE LARGE UPPER LOW CONTINUES MOVING SOUTHEAST WITH THE
CENTER OF THE LOW ARRIVING ON THE COAST JUST NORTH OF THE COLUMBIA
RIVER BY TUESDAY AFTERNOON. THIS WILL CAUSE A SOUTHWEST FLOW ALOFT
TO BACK TO THE SOUTH OVER THE INTERIOR PACIFIC NORTHWEST AND
TRANSPORT MOISTURE AND INCREASING INSTABILITY INTO THE REGION. THE
APPROACHING COLD UPPER LOW WILL USHER IN A COOLING TREND, AS THE
UPPER LOW CENTER COMES NEARER TO THE FORECAST AREA. THE UPPER LOW
WILL PERSIST OVER THE PACIFIC NORTHWEST THROUGH THURSDAY. HOWEVER,
FROM ONE RUN TO THE NEXT, THE GFS AND ECMWF SOLUTIONS ARE EXHIBITING
SIGNIFICANT DIFFERENCES IN THE PLACEMENT OF THE CENTER OF THE UPPER
LOW, AND A COMPARISON OF THE PLACEMENT OF THE CENTER OF THE UPPER
LOW BETWEEN THE GFS AND ECMWF MODELS FOR A GIVEN FORECAST BASE TIME
LIKEWISE SHOW SIGNIFICANT DIFFERENCES. AS SUCH UNCERTAINTY IN THE
FORECAST IS GREATER THAN NORMAL FOR TUESDAY THROUGH FRIDAY IN TERMS
OF LARGE STANDARD DEVIATIONS IN THE OVERALL 500MB HEIGHT PATTERN IN
BOTH MODELS. HOWEVER, WITH EACH ADDITIONAL MODEL RUN, THE GFS AND
ECMWF MODELS ARE DISPLAYING BETTER AGREEMENT FOR TUESDAY THROUGH
FRIDAY. EXPECT COOL AND UNSETTLED CONDITIONS WITH PERIODS OF SHOWERS
EACH DAY FROM TUESDAY THROUGH THURSDAY. THE UPPER LOW PERSISTS OVER
THE INTERIOR PACIFIC NORTHWEST THROUGH FRIDAY THUS RESULTING IN
DAYTIME HIGH TEMPERATURES BEING SLIGHTLY COOLER THAN NORMAL. POLAN
&&
.AVIATION...06Z TAFS...VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24
HOURS. THERE MAY BE BRIEF MVFR CONDITIONS AT KRDM AND KBDN DUE TO
SHOWERS AFTER 18Z. OTHERWISE CIGS WILL BE SCT TO BKN 5KFT AND BKN
TO OVC 10KFT THROUGH 03Z WITH CONDITIONS GRADUALLY IMPROVING. WINDS
WILL BE BETWEEN 5-15KTS GUSTING TO 25KTS AT TIMES. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 66 45 68 42 / 20 20 10 0
ALW 69 51 69 46 / 20 20 10 0
PSC 74 50 74 44 / 20 10 10 0
YKM 70 48 72 45 / 20 10 10 0
HRI 72 49 72 43 / 20 10 10 0
ELN 68 47 69 42 / 20 10 10 0
RDM 63 35 63 29 / 30 20 10 0
LGD 62 45 62 39 / 20 20 20 0
GCD 62 43 63 38 / 30 20 10 10
DLS 66 50 68 44 / 20 20 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
76/99/99
000
FXUS66 KMFR 180946
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
246 AM PDT SAT MAY 18 2013
.DISCUSSION...A MID LEVEL TROUGH AXIS AND ASSOCIATED TROUGH AXIS
WILL PASS OVER THE FORECAST AREA TODAY...AND WILL RESULT IN RAIN
OVER MUCH OF THE AREA. LOCATIONS ALONG THE COAST...THE UMPQUA
BASIN...AND ALONG THE CASCADES WILL BE THE MAJOR FOCUS OF PRECIP
TODAY...BUT THERE IS A CHANCE OF RAIN OVER VIRTUALLY ALL PARTS OF
THE CWA THROUGH THIS EVENING. HAVE DEBATED ON THE POSSIBILITY OF
THUNDER OVER MY FAR EASTERN ZONES LATE THIS MORNING AND EARLY THIS
AFTERNOON. THE GFS AND NAM BOTH DEPICT SOME WEAK INSTABILITY...AS
WELL AS LIFTED INDICES OF -2 AND A WIDE AREA OF POTENTIAL LIFT.
HAVE THEREFORE INCREASED IN COVERAGE THE SLIGHT CHANCE OF THUNDER
OVER PORTIONS OF LAKE AND MODOC COUNTIES THAT WAS INTRODUCED BY
EARLIER SHIFTS. OVERALL...PRECIPITATION WILL DECREASE IN COVERAGE
OVERNIGHT...BUT SHOWERS COULD LINGER OVER THE CASCADES AND THE
UMPQUA BASIN THROUGH EARLY SUNDAY MORNING.
ONCE THE TROUGH EXITS THE AREA SUNDAY MORNING...RIDGING WILL
BUILD UP THE COAST AND INTO THE PACIFIC NORTHWEST. THE THERMAL
TROUGH WILL RETURN DURING THIS TIME...AND THE USUAL CONDITIONS
EXPECTED WITH THE FEATURE WILL RETURN. DRY OFFSHORE FLOW WILL
PREVAIL...AND WARMER THAN NORMAL TEMPERATURES ARE EXPECTED UNDER
MOSTLY CLEAR SKIES...WHILE WINDS ALONG THE COAST AND ACROSS HIGHER
TERRAIN WILL BE GUSTY. THERE IS ALSO A HIGH LIKELIHOOD OF THE
CHETCO EFFECT TO DEVELOP SUNDAY AND MONDAY...THUS HIGHER THAN
NORMAL TEMPERATURES ALONG THE SOUTHWESTERN COAST OF OREGON ARE
EXPECTED.
THE RIDGE AND THERMAL TROUGH WILL BE SHORT LIVED...AS A POTENT CUT
OFF LOW WILL DESCEND SOUTHWARD FROM THE GULF OF ALASKA TOWARDS THE
PACIFIC NORTHWEST BEGINNING MONDAY NIGHT. THE LOW IS EXPECTED TO
TAKE UP STATION DIRECTLY OVER OREGON AND WASHINGTON BY TUESDAY
NIGHT...AND REMAIN IN THE AREA FOR SEVERAL DAYS. MODEL SOLUTIONS
DEPICT THE LOW WOBBLING AROUND THE AREA AS MULTIPLE SHORTWAVES
ORBIT AROUND IT. THE 12Z ECMWF RUN PRODUCED A SMALL KICKER LOW
THAT SHUNTS THE CLOSED LOW OUT OF THE AREA MUCH SOONER...BUT HAS
RETURNED TO A MORE LONG LIVED EVENT WITH THE 00Z RUN. IT IS
BELIEVED THAT THE MODELS WILL HAVE A DIFFICULT TIME RESOLVING THE
BEHAVIOR OF THE SYSTEM...DUE TO THE INHERENT DIFFICULTIES THEY
TEND TO HAVE WITH CUT OFF LOWS...AND DUE TO THE POSSIBILITY OF A
BLOCKING RIDGE DEVELOPING OVER CENTRAL NORTH AMERICA...WHICH BOTH
THE GFS AND ECMWF HAVE DEPICTED IN SEVERAL RUNS. THIS INTRODUCES
QUITE A BIT OF UNCERTAINTY TO THE FORECAST...BUT THERE IS A GREAT
DEAL OF CONFIDENCE IN THE OVERALL PATTERN THAT CAN BE
EXPECTED...ONE OF COOLER THAN NORMAL TEMPERATURES AND A GOOD
CHANCE FOR MULTIPLE PERIODS OF RAIN. THE DAY TO DAY POPS WILL
DEPEND A GREAT DEAL ON THE WOBBLE OF THE LOW...THE INDIVIDUAL
TIMING AND STRENGTHS OF THE ORBITING SHORTWAVES...AND THE
AVAILABILITY OF MOISTURE. HAVE THEREFORE KEPT POPS ABOVE CLIMO AND
TEMPERATURES BELOW NORMAL FOR THE DURATION OF THE EXTENDED TERM.
THAT BEING SAID...THERE IS A POTENTIAL FOR LATE MAY SNOWFALL OVER
THE CASCADES...PORTIONS OF THE EAST SIDE...AND EVEN SOME OF THE
PASSES...AS SNOW LEVELS COULD EASILY DROP TO BELOW 4000 FEET. ALL
OF THESE DETAILS WILL SLOWLY COME INTO FOCUS DURING THE NEXT FEW
FORECAST CYCLES...BUT FOR NOW...ANYONE WITH OUTDOOR INTERESTS
DURING THE MEMORIAL DAY WEEKEND SHOULD BE PREPARED TO CONTEND WITH
COLD AND WET WEATHER...AND EVEN SOME SNOW IN THE HIGHER
ELEVATIONS.
&&
.AVIATION...BASED ON THE 18/06Z TAF CYCLE.
CEILINGS WILL LOWER TO MVFR THIS MORNING ALONG THE COAST AND IN THE
UMPQUA VALLEY AS A COLD FRONT MOVES IN. TERRAIN OBSCURATION WILL BE
PREVALENT ALONG AND WEST OF THE CASCADES. THERE WILL ALSO BE AREAS
OF LIGHT RAIN ALONG THE FRONT THIS MORNING TAPERING OFF TO SHOWERS
BEHIND IT THIS AFTERNOON. MOSTLY VFR IS EXPECTED AT KMFR, BUT
CEILINGS MAY BRIEFLY LOWER TO NEAR MVFR WITH A SHOWER IN THE
VICINITY THIS AFTERNOON. EAST OF THE CASCADES, EXPECT MOSTLY VFR
THOUGH CIGS MAY ALSO BRIEFLY LOWER TO MVFR IN AND NEAR ANY SHOWERS.
GUSTY WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS AFTERNOON/EARLY
THIS EVENING WITH GUSTS JUST SHY OF 30KT AT KLMT. THUNDER POTENTIAL
IS SLIM AND WILL LIKELY BE RESTRICTED TO AREAS ALONG AND EAST OF THE
WARNER MOUNTAINS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...GALE WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY EVENING FOR
PZZ376.
HAZARDOUS SEAS WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR PZZ376.
$$
BPN/MAS
000
FXUS66 KPQR 180946
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
246 AM PDT SAT MAY 18 2013
.SYNOPSIS...A COLD FRONT WILL SPREAD LIGHT RAIN ACROSS THE REGION
TODAY. SHOWERS WILL DECREASE TONIGHT BUT CONTINUE OVER THE MOUNTAINS
THROUGH SUNDAY MORNING. HIGH PRESSURE WILL RESULT IN DRIER AND
GRADUALLY WARMER TEMPERATURES SUNDAY AND MONDAY. AN UPPER LEVEL LOW
WILL BRING A RETURN OF RAIN AND MUCH COLDER WEATHER TUESDAY WITH
LIGHT SNOW ACCUMULATIONS POSSIBLE BELOW THE CASCADE PASSES BY
WEDNESDAY MORNING. COOL AND SHOWERY WEATHER WILL CONTINUE THROUGH
FRIDAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...THE NEXT FRONT IS
APPROACHING THE COAST. ASCAT SATELLITE DERIVED WINDS SHOWED THE COLD
FRONT AROUND 300 MILES OFFSHORE AT 11 PM LAST NIGHT. RADAR IMAGERY
SHOWS RAIN AHEAD OF THE FRONT JUST REACHING THE NORTHERN OREGON COAST
AT 2 AM THIS MORNING. AMSU SHOWS TROPICAL PRECIPITABLE WATER AROUND
AN INCH WITH THE FRONT. AN UPPER LEVEL JET POINTED TOWARDS SOUTHERN
OREGON WILL PROVIDE ENOUGH LIFT TO TAP INTO THIS MOISTURE...RESULTING
IN LIGHT RAIN OVER MUCH OF THE REGION TODAY. THE FRONT SHOULD MOVE
ACROSS NW OREGON THIS AFTERNOON WITH ISOLATED TO SCATTERED
POST-FRONTAL SHOWERS TONIGHT.
SHOWERS OVER THE HIGHER TERRAIN WILL LIKELY PERSIST THROUGH SUNDAY
MORNING...BUT OTHERWISE DRY WEATHER CAN BE EXPECTED SUNDAY AS HIGH
PRESSURE BUILDS OVER THE AREA. SUNDAY MORNING WILL LIKELY BE CLOUDY
WITH PARTIAL CLEARING IN THE AFTERNOON...LEADING TO INLAND DAYTIME
HIGHS IN THE MID TO UPPER 60S AND COASTAL HIGHS IN THE UPPER
50S...SLIGHTLY BELOW THE SEASONAL NORMAL.
HIGH PRESSURE MAINTAIN DRY WEATHER FOR MONDAY WHICH WILL LIKELY BE
THE WARMEST DAY OF THE WEEK. INCREASED SUNSHINE SHOULD WARM INTERIOR
TEMPERATURES TO SLIGHTLY ABOVE NORMAL...LOW 70S AND COASTAL AREAS TO
NEAR NORMAL...LOWER 60S.
AN UPPER LEVEL LOW WILL APPROACH MONDAY NIGHT AND BRING A RETURN OF
SHOWERS AND MUCH COOLER WEATHER TO THE REGION. MODELS HAVE BACKED OFF
THE TIMING OF THE ONSET OF RAIN AROUND 12 HOURS. THE COLDEST AIR
ASSOCIATED WITH THE LOW WILL BEGIN MOVING OVER THE AREA TUESDAY NIGHT
AND SNOW LEVELS SHOULD LOWER TO AROUND 3500 TO 4000 FEET.
.LONG TERM...WEDNESDAY THROUGH FRIDAY...A COLD CLOSED LOW WILL
CONTINUE UNSETTLED WEATHER WITH UNSEASONAL COLD TEMPERATURES
WEDNESDAY...WITH RECORD LOW MAXIMUM TEMPERATURES POSSIBLE. WEDNESDAY
WILL BE THE COLDEST DAY OF THE WORK WEEK. TEMPERATURES WILL REMAIN
BELOW THE SEASONAL NORMALS THURSDAY AND FRIDAY AS A COUPLE OF
SHORTWAVE TROUGHS WILL CONTINUE SHOWERY AND COOL CONDITIONS.
&&
.AVIATION...A FRONT WILL APPROACH THE AREA THIS MORNING WITH CIGS
GRADUALLY LOWERING...WITH MVFR AND OCCASIONAL RAIN INCREASING BETWEEN
10Z AND 14Z. FRONT IS FAST MOVING...SO RETURN TO VFR LIKELY
BETWEEN 19Z AND 22Z...FIRST ON COAST AND LATER INLAND AS THE FRONT
SWEEPS EAST OF THE CASCADES BY MID AFTERNOON.
KPDX AND APPROACHES...VFR CONDITIONS FOR THE NEXT COUPLE OF HOURS.
AREAS OF MVFR CIGS DOWN NEAR 2500 FT INCREASE BETWEEN 12Z AND 15Z.
FRONT WILL PUSH ACROSS KPDX OPS AREA BETWEEN 20Z AND 22Z...WITH
RETURN TO VFR WITH SCATTERED SHOWERS.
&&
.MARINE...A FRONT WILL PUSH ACROSS THE COASTAL WATERS THIS
MORNING...THEN INLAND IN THE AFTERNOON. WINDS NOT ALL THAT
IMPRESSIVE BUT THERE SEEMS SO BE ENOUGH GRADIENT TO POP GUSTS 20
TO 25 KT THIS MORNING. SO WILL MAINTAIN CURRENT SMALL CRAFT
ADVISORY. OTHERWISE...WINDS TURN W TO NW BEHIND THE FRONT IN THE
AFTERNOON AND BEGIN TO EASE.
HIGH PRES WILL BUILD OVER THE NE PAC SUN INTO EARLY NEXT WEEK.
THIS WILL KEEP NW WINDS 10 TO 15 KT THROUGH MUCH OF THE COMING
WEEK...THOUGH MAY BRIEFLY GET 20 TO 25 KT GUSTS MON AFTERNOON INTO
THE EVENING.
SEAS REMAIN AT 5 TO 6 FT FOR INTO EARLY NEXT WEEK. MAY SEE SEAS
BUILD UP AND BECOME CHOPPY AT TIMES WITH THE BRISK NW WINDS ON THE
CENTRAL OREGON COASTAL WATERS NEXT WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 6 AM TO NOON
PDT TODAY FOR ALL COASTAL WATERS.
&&
$$
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.
000
FXUS65 KBOI 180922 CCA
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
322 AM MDT SAT MAY 18 2013
.SHORT TERM...ONE UPPER TROUGH EXITING EAST THIS MORNING AS ANOTHER
TROUGH COMES IN FROM THE NORTHWEST AND FORMS A WEAK CLOSED LOW OVER
OUR CWA TONIGHT. THESE TROUGHS WILL KEEP MAX TEMPS BELOW NORMAL
THIS WEEKEND. OUR FORECAST MAX TEMPS ARE CLOSER TO THE COOLER MET
MOS THAN THE MAV MOS BOTH TODAY AND SUNDAY. MIN TEMPS TONIGHT ARE
CLOSE TO MAV AND MET MOS WHICH ARE RELATIVELY CLOSE TO EACH OTHER.
SCATTERED SHOWERS WILL CONTINUE IN HIGHER TERRAIN....SNOW ON HIGHEST
PEAKS. ONLY ISOLATED SHOWERS AT MOST AT LOWER ELEVATIONS INCLUDING
THE SNAKE BASIN. AIR MASS MAGINALLY UNSTABLE THIS AFTERNOON AND
EARLY EVENING WITH ISOLATED THUNDERSTORMS AGAIN IN HIGHER TERRAIN
IN BOTH OREGON AND IDAHO...BUT ONLY ON THE IDAHO SIDE SUNDAY
AFTERNOON. BREEZY WINDS THIS AFTERNOON IN THE SNAKE BASIN AND IN
EASTERN OREGON. SUNDAY AFTERNOON WILL BE WINDIER ESPECIALLY IN THE
SNAKE BASIN AS NORTHWEST WINDS ALOFT ALIGN WITH PRESSURE GRADIENT AT
THE SURFACE.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY...WARMER AND
SIGNIFICANTLY DRIER SUNDAY NIGHT THROUGH EARLY TUESDAY AS A SHORT
WAVE RIDGE MOVES OVER THE GREAT BASIN. RIDGE WILL BE FORCED
EASTWARD TUESDAY EVENING...AS A DEEP UPPER LEVEL LOW MOVES SOUTH
ALONG THE PACIFIC NORTHWEST COAST. ASSOCIATED COLD FRONT WILL CROSS
SE OREGON AND SW IDAHO TUESDAY NIGHT. EXPECT INCREASED WINDS...A
CHANCE OF PRECIPITATION...AND A DRAMATIC DROP IN TEMPERATURES /FROM
TUESDAY/ BY WEDNESDAY AFTERNOON. UPPER LOW WILL HOLD STRONG OVER THE
PACIFIC NORTHWEST THROUGH THE EXTENDED PERIOD WARRANTING A FORECAST
OF BELOW NORMAL TEMPERATURES AND PERIODS OF PRECIPITATION THURSDAY
THROUGH SUNDAY.
&&
.AVIATION...THROUGH 21Z...FOG AND STRATUS ACROSS THE LONG VALLEY
/INCLUDING KMYL/ WILL DISSIPATE BY 14Z. VFR ELSEWHERE. LIGHT WINDS
W/NW SURFACE WINDS. AFTER 21Z...SCATTERED MVFR SHOWERS AND
THUNDERSTORMS - ACROSS SE OREGON AND ALONG THE ID/NV BORDER THROUGH
00Z. CLOUD BASES GENERALLY 8K FT MSL. W/NW SURFACE WINDS WILL
AVERAGE 10 TO 15 KTS WITH LOCAL GUSTS TO 25 KTS. WESTERLY WINDS
ALOFT WILL AVERAGE 20 KTS AT 10K FT MSL.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...LC
LONG TERM....MT
AVIATION.....MT
000
FXUS66 KPDT 180545 AAA
AFDPDT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON
1045 PM PDT FRI MAY 17 2013
UPDATED FOR AVIATION DISCUSSION
.UPDATE...ISOLATED SHOWERS REMAIN ALONG THE FOOTHILLS OF THE BLUE
MOUNTAINS AND PORTIONS OF NORTHEAST OREGON BUT NO THUNDER
ASSOCIATED. EXPECT THESE SHOWERS TO DIMINISH OVER THE NEXT COUPLE
OF HOURS. WONT STILL RULE OUT A SLIGHT CHANCE OF A SHOWER OR TWO
OVERNIGHT FOR THE MOUNTAINS AREAS. SO HAVE KEPT A SLIGHT CHANCE
ACROSS THE HIGHER ELEVATIONS. MODELS CONTINUE TO BACK OFF ON THE
INSTABILITY TO SUPPORT THUNDER TOMORROW. RIGHT NOW SOUTH CENTRAL
PORTIONS OF OREGON LOOK TO HAVE THE BEST CHANCE FOR THUNDER...AND
EVEN IN THOSE AREAS IT LOOKS TO BE ISOLATED. WEBER
&&
.AVIATION...06Z TAFS...VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24
HOURS. THERE MAY BE BRIEF MVFR CONDITIONS AT KRDM AND KBDN DUE TO
SHOWERS AFTER 18Z. OTHERWISE CIGS WILL BE SCT TO BKN 5KFT AND BKN
TO OVC 10KFT THROUGH 03Z WITH CONDITIONS GRADUALLY IMPROVING. WINDS
WILL BE BETWEEN 5-15KTS GUSTING TO 25KTS AT TIMES. WEBER
&&
.PREV DISCUSSION... /ISSUED 220 PM PDT FRI MAY 17 2013/
SHORT TERM...TONIGHT THROUGH MONDAY...A WEATHER DISTURBANCE
CONTINUES TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON. THERE
WERE LIGHT RAIN SHOWERS REPORTED ACROSS THE BLUE MOUNTAIN FOOTHILLS
AND THE LOWER COLUMBIA BASIN...BUT PRECIPITATION AMOUNTS WERE MAINLY
JUST TRACE AMOUNTS. THE UPPER TROUGH ASSOCIATED WITH THIS SYSTEM IS
NOW LOCATED OVER THE CWA AND IT WILL SLOWLY LIFT OUT TO THE
NORTHEAST TONIGHT. ON SATURDAY ANOTHER WEATHER DISTURBANCE WILL MOVE
INTO THE REGION BRINGING ANOTHER CHANCE OF LIGHT RAIN SHOWERS...
MAINLY TO THE MOUNTAINS...HOWEVER CANNOT RULE OUT A LIGHT SPRINKLE
ELSEWHERE. AGAIN PRECIPITATION AMOUNTS WILL BE VERY LIGHT. THE UPPER
TROUGH WITH THIS NEXT SYSTEM WILL MOVE ACROSS THE CWA LATE SATURDAY
AFTERNOON AND EVENING. BEHIND IT AN UPPER RIDGE WILL BEGIN TO BUILD
INTO THE REGION WITH A DRIER NORTHWEST FLOW ALOFT BEGINNING BY LATE
SUNDAY. THIS UPPER RIDGE WILL PERSIST THROUGH MONDAY EVENING. EXPECT
WARMER TEMPERATURES ON MONDAY AS A RESULT WITH MAXIMUM TEMPERATURE
READINGS CLIMBING BACK INTO THE MID 70S IN THE LOWER ELEVATIONS AND
MID 50S TO MID 60S IN THE MOUNTAINS. THIS WILL BE SLIGHTLY ABOVE
NORMAL. A LARGE UPPER TROUGH WILL THEN SWING DOWN FROM THE GULF OF
ALASKA GOING INTO THE EXTENDED PERIOD WITH COOLER CONDITIONS AND
MORE CHANCES OF PRECIPITATION. 88
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...A RIDGE OF HIGH
PRESSURE SHOULD BRING A WARMER AND MAINLY DRY DAY FOR MONDAY. A
DISTURBANCE WILL APPROACH THE TWO STATE AREA MONDAY NIGHT THAT COULD
SPREAD SOME SHOWERS ALONG THE WA/OR CASCADES. AS A STRONG LOW
PRESSURE SYSTEM DIPS TOWARD THE PACNW TUESDAY...THE SHOWERS SHOULD
MOVE INTO THE REMAINDER OF THE REGION. THE LOW PRESSURE REMAINS
NEARLY STATIONARY AND KEEPS THE CLOUDS AND SHOWERS ALONG WITH THE
COOL TEMPERATURES ACROSS THE TWO STATE AREA THROUGH THURSDAY. THE
LOW IS FORECAST TO DRIFT NORTH AND SOME DRYING IS POSSIBLE FOR
FRIDAY AND SATURDAY ALONG WITH SLIGHTLY WARMER TEMPERATURES.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 66 40 67 / 20 20 20 10
ALW 48 68 45 67 / 20 20 20 10
PSC 48 73 45 72 / 10 20 10 10
YKM 44 68 42 70 / 10 20 10 10
HRI 46 70 45 70 / 10 20 10 10
ELN 45 66 43 66 / 10 20 10 10
RDM 37 61 30 60 / 10 30 20 10
LGD 40 62 40 60 / 30 20 20 20
GCD 41 59 36 61 / 20 30 20 10
DLS 48 65 45 65 / 10 20 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SATURDAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
89/97/89
000
FXUS65 KBOI 180326 CCA
AFDBOI
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE BOISE ID
925 PM MDT FRI MAY 17 2013
.DISCUSSION...A NEGATIVELY TILTED UPPER LEVEL TROUGH AXIS FROM
AROUND PORTLAND OREGON TO ELKO NEVADA AT 8 PM BROUGHT LARGE SCALE
LIFT ACROSS SE OREGON AND SW IDAHO THIS AFTERNOON. ISOLATED
THUNDERSTORMS EXTENDED FROM NORTH MALHEUR COUNTY TO CENTRAL OWYHEE
COUNTY AND WERE LIFTING TOWARDS THE NORTHEAST AT 10-15 MPH. THIS
TROUGH AXIS WILL SPREAD THROUGH SW IDAHO TONIGHT AND LIKELY KEEP
ISOLATED THUNDERSTORMS GOING WITH IT...UNTIL AROUND MIDNIGHT
INCLUDING FOR THE TREASURE VALLEY. EVENING WEATHER BALLOON
SOUNDING SHOWED INSTABILITY OF -1.4C LI AND 341 J/KG CAPE ALONG
WITH LIGHT SHEAR OF LESS THAN 20 M/S...SO STORMS LOOK TO REMAIN
PULSE-LIKE WITH LOCAL GUSTS OF 30 MPH BUT UP TO 45 MPH...SUCH AS
OCCURRED AT GRASSY MOUNTAIN RAWS IN THE LATE AFTERNOON. SMALL HAIL
WAS REPORTED WITH ANOTHER STRONGER LOOKING CELL NEAR BUHL AND A
MENACING LOOKING SHELF CLOUD AND RAIN OR RAIN AND HAIL SHAFT WAS
SHARED VIA FACEBOOK FROM THE CASTLEFORD AREA. FORECAST IS ON
TRACK WITH NO UPDATES EXPECTED.
&&
.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY SOUTH AND
WEST OF THE SNAKE RIVER PLAIN AT 02Z WILL PUSH EAST-NORTHEAST THIS
EVENING. EXPECT BRIEF MVFR CEILINGS...HEAVY RAIN AND GUSTY WINDS
WITH THESE STORMS. OTHERWISE...SCATTERED TO BROKEN CLOUDS DECK
GENERALLY AT 5K-7K FEET ASL. WEST-NORTHWEST SURFACE WINDS AT 10-15
KTS. WEST WINDS ALOFT UP TO 20 KTS AT 10K FEET MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY AFTERNOON - MAINLY ACROSS SE OREGON AND
HIGHER TERRAIN OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS
CONFINED TO THE CENTRAL IDAHO MOUNTAINS AND EASTWARD.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH SUNDAY...HEATING OF THE DAY COMBINED
WITH MOISTURE ASSOCIATED WITH AN UPPER TROUGH WAS RESULTING IN
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. INSTABILITY WAS MARGINAL
TO SUPPORT THUNDERSTORMS...ALTHOUGH ENOUGH TO KEEP ISOLATED COVERAGE
IN THE FORECAST THROUGH THIS EVENING. DRIER STABLE AIR WILL
TEMPORARILY MOVE INTO SE OREGON LATE TONIGHT AND SATURDAY MORNING
WITH A SHORT WAVE UPPER RIDGE. ANOTHER TROUGH WILL THEN MOVE INTO
THE PACNW SATURDAY AFTERNOON...THEN SLOWLY WORK EASTWARD ACROSS THE
AREA THROUGH SUNDAY. THE SECOND TROUGH WILL BRING MORE MOISTURE AND
A CHANCE OF MOUNTAIN/SLIGHT CHANCE OF VALLEY SHOWERS...ALTHOUGH THE
SYSTEM WILL BE WEAKER AND WITH LESS MOISTURE. SNOW LEVELS WILL LOWER
TO AROUND 7500 FEET MSL WITH LIGHT SNOW ACCUMULATIONS POSSIBLE ON
THE PEAKS. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL THROUGH
THE WEEKEND. BREEZY NORTHWEST WINDS ARE EXPECTED SATURDAY AFTERNOON
WITH A LITTLE STRONGER WINDS EXPECTED SUNDAY AFTERNOON...ESPECIALLY
IN THE UPPER TREASURE VALLEY AND WESTERN MAGIC VALLEY.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...A SHORTWAVE RIDGE WILL
BUILD INTO THE AREA FROM THE WEST EARLY MONDAY...ALLOWING SKIES TO
CLEAR AND TEMPS TO RISE TO NEAR NORMAL VALUES MONDAY AFTERNOON. AS A
DEEP LOW PRESSURE SYSTEM SLIDES SOUTHWARD INTO THE PACIFIC NORTHWEST
ON TUESDAY...SOUTHWEST FLOW WILL PICK UP OVER THE INTERMOUNTAIN WEST
WHICH WILL DRIVE THE AFTERNOON HIGH TEMPERATURES TO AROUND 5 DEGREES
ABOVE NORMAL. THE LOW WILL CONTINUE TO MOVE SOUTHWARD...BRINGING A
STRONG SURFACE COLD FRONT THROUGH SE OREGON AND SW IDAHO LATE TUESDAY
NIGHT. EXPECT HIGH TEMPS ON WEDNESDAY TO BE NEARLY 20 DEGREES COOLER
THAN TUESDAY. THE LOW PRESSURE SYSTEM WILL STALL OUT OVER THE PAC NW
THROUGH THE END OF THE WEEK...KEEPING CONDITIONS COOL AND UNSETTLED.
MOST OF THE AVAILABLE MOISTURE LOOKS TO BE ON THE NORTHERN HALF OF
THE LOW CIRCULATION...WITH THE SOUTHERN PORTION OF THE LOW AFFECTING
OUR AREA. THUS THE BEST CHANCE FOR SHOWERS WILL BE ACROSS OUR
NORTHERN AND WESTERN MOUNTAIN ZONES.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JS
PREV SHORT TERM...BW
PREV LONG TERM....CB
000
FXUS65 KBOI 180326 CCA
AFDBOI
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE BOISE ID
925 PM MDT FRI MAY 17 2013
.DISCUSSION...A NEGATIVELY TILTED UPPER LEVEL TROUGH AXIS FROM
AROUND PORTLAND OREGON TO ELKO NEVADA AT 8 PM BROUGHT LARGE SCALE
LIFT ACROSS SE OREGON AND SW IDAHO THIS AFTERNOON. ISOLATED
THUNDERSTORMS EXTENDED FROM NORTH MALHEUR COUNTY TO CENTRAL OWYHEE
COUNTY AND WERE LIFTING TOWARDS THE NORTHEAST AT 10-15 MPH. THIS
TROUGH AXIS WILL SPREAD THROUGH SW IDAHO TONIGHT AND LIKELY KEEP
ISOLATED THUNDERSTORMS GOING WITH IT...UNTIL AROUND MIDNIGHT
INCLUDING FOR THE TREASURE VALLEY. EVENING WEATHER BALLOON
SOUNDING SHOWED INSTABILITY OF -1.4C LI AND 341 J/KG CAPE ALONG
WITH LIGHT SHEAR OF LESS THAN 20 M/S...SO STORMS LOOK TO REMAIN
PULSE-LIKE WITH LOCAL GUSTS OF 30 MPH BUT UP TO 45 MPH...SUCH AS
OCCURRED AT GRASSY MOUNTAIN RAWS IN THE LATE AFTERNOON. SMALL HAIL
WAS REPORTED WITH ANOTHER STRONGER LOOKING CELL NEAR BUHL AND A
MENACING LOOKING SHELF CLOUD AND RAIN OR RAIN AND HAIL SHAFT WAS
SHARED VIA FACEBOOK FROM THE TCASTLEFORD AREA. FORECAST IS ON
TRACK WITH NO UPDATES EXPECTED.
&&
.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY SOUTH AND
WEST OF THE SNAKE RIVER PLAIN AT 02Z WILL PUSH EAST-NORTHEAST THIS
EVENING. EXPECT BRIEF MVFR CEILINGS...HEAVY RAIN AND GUSTY WINDS
WITH THESE STORMS. OTHERWISE...SCATTERED TO BROKEN CLOUDS DECK
GENERALLY AT 5K-7K FEET ASL. WEST-NORTHWEST SURFACE WINDS AT 10-15
KTS. WEST WINDS ALOFT UP TO 20 KTS AT 10K FEET MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY AFTERNOON - MAINLY ACROSS SE OREGON AND
HIGHER TERRAIN OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS
CONFINED TO THE CENTRAL IDAHO MOUNTAINS AND EASTWARD.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH SUNDAY...HEATING OF THE DAY COMBINED
WITH MOISTURE ASSOCIATED WITH AN UPPER TROUGH WAS RESULTING IN
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. INSTABILITY WAS MARGINAL
TO SUPPORT THUNDERSTORMS...ALTHOUGH ENOUGH TO KEEP ISOLATED COVERAGE
IN THE FORECAST THROUGH THIS EVENING. DRIER STABLE AIR WILL
TEMPORARILY MOVE INTO SE OREGON LATE TONIGHT AND SATURDAY MORNING
WITH A SHORT WAVE UPPER RIDGE. ANOTHER TROUGH WILL THEN MOVE INTO
THE PACNW SATURDAY AFTERNOON...THEN SLOWLY WORK EASTWARD ACROSS THE
AREA THROUGH SUNDAY. THE SECOND TROUGH WILL BRING MORE MOISTURE AND
A CHANCE OF MOUNTAIN/SLIGHT CHANCE OF VALLEY SHOWERS...ALTHOUGH THE
SYSTEM WILL BE WEAKER AND WITH LESS MOISTURE. SNOW LEVELS WILL LOWER
TO AROUND 7500 FEET MSL WITH LIGHT SNOW ACCUMULATIONS POSSIBLE ON
THE PEAKS. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL THROUGH
THE WEEKEND. BREEZY NORTHWEST WINDS ARE EXPECTED SATURDAY AFTERNOON
WITH A LITTLE STRONGER WINDS EXPECTED SUNDAY AFTERNOON...ESPECIALLY
IN THE UPPER TREASURE VALLEY AND WESTERN MAGIC VALLEY.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...A SHORTWAVE RIDGE WILL
BUILD INTO THE AREA FROM THE WEST EARLY MONDAY...ALLOWING SKIES TO
CLEAR AND TEMPS TO RISE TO NEAR NORMAL VALUES MONDAY AFTERNOON. AS A
DEEP LOW PRESSURE SYSTEM SLIDES SOUTHWARD INTO THE PACIFIC NORTHWEST
ON TUESDAY...SOUTHWEST FLOW WILL PICK UP OVER THE INTERMOUNTAIN WEST
WHICH WILL DRIVE THE AFTERNOON HIGH TEMPERATURES TO AROUND 5 DEGREES
ABOVE NORMAL. THE LOW WILL CONTINUE TO MOVE SOUTHWARD...BRINGING A
STRONG SURFACE COLD FRONT THROUGH SE OREGON AND SW IDAHO LATE TUESDAY
NIGHT. EXPECT HIGH TEMPS ON WEDNESDAY TO BE NEARLY 20 DEGREES COOLER
THAN TUESDAY. THE LOW PRESSURE SYSTEM WILL STALL OUT OVER THE PAC NW
THROUGH THE END OF THE WEEK...KEEPING CONDITIONS COOL AND UNSETTLED.
MOST OF THE AVAILABLE MOISTURE LOOKS TO BE ON THE NORTHERN HALF OF
THE LOW CIRCULATION...WITH THE SOUTHERN PORTION OF THE LOW AFFECTING
OUR AREA. THUS THE BEST CHANCE FOR SHOWERS WILL BE ACROSS OUR
NORTHERN AND WESTERN MOUNTAIN ZONES.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JS
PREV SHORT TERM...BW
PREV LONG TERM....CB
000
FXUS66 KPDT 180321
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON
820 PM PDT FRI MAY 17 2013
.UPDATE...ISOLATED SHOWERS REMAIN ALONG THE FOOTHILLS OF THE BLUE
MOUNTAINS AND PORTIONS OF NORTHEAST OREGON BUT NO THUNDER
ASSOCIATED. EXPECT THESE SHOWERS TO DIMINISH OVER THE NEXT COUPLE
OF HOURS. WONT STILL RULE OUT A SLIGHT CHANCE OF A SHOWER OR TWO
OVERNIGHT FOR THE MOUNTAINS AREAS. SO HAVE KEPT A SLIGHT CHANCE
ACROSS THE HIGHER ELEVATIONS. MODELS CONTINUE TO BACK OFF ON THE
INSTABILITY TO SUPPORT THUNDER TOMORROW. RIGHT NOW SOUTH CENTRAL
PORTIONS OF OREGON LOOK TO HAVE THE BEST CHANCE FOR THUNDER...AND
EVEN IN THOSE AREAS IT LOOKS TO BE ISOLATED. WEBER
&&
.PREV DISCUSSION... /ISSUED 220 PM PDT FRI MAY 17 2013/
SHORT TERM...TONIGHT THROUGH MONDAY...A WEATHER DISTURBANCE
CONTINUES TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON. THERE
WERE LIGHT RAIN SHOWERS REPORTED ACROSS THE BLUE MOUNTAIN FOOTHILLS
AND THE LOWER COLUMBIA BASIN...BUT PRECIPITATION AMOUNTS WERE MAINLY
JUST TRACE AMOUNTS. THE UPPER TROUGH ASSOCIATED WITH THIS SYSTEM IS
NOW LOCATED OVER THE CWA AND IT WILL SLOWLY LIFT OUT TO THE
NORTHEAST TONIGHT. ON SATURDAY ANOTHER WEATHER DISTURBANCE WILL MOVE
INTO THE REGION BRINGING ANOTHER CHANCE OF LIGHT RAIN SHOWERS...
MAINLY TO THE MOUNTAINS...HOWEVER CANNOT RULE OUT A LIGHT SPRINKLE
ELSEWHERE. AGAIN PRECIPITATION AMOUNTS WILL BE VERY LIGHT. THE UPPER
TROUGH WITH THIS NEXT SYSTEM WILL MOVE ACROSS THE CWA LATE SATURDAY
AFTERNOON AND EVENING. BEHIND IT AN UPPER RIDGE WILL BEGIN TO BUILD
INTO THE REGION WITH A DRIER NORTHWEST FLOW ALOFT BEGINNING BY LATE
SUNDAY. THIS UPPER RIDGE WILL PERSIST THROUGH MONDAY EVENING. EXPECT
WARMER TEMPERATURES ON MONDAY AS A RESULT WITH MAXIMUM TEMPERATURE
READINGS CLIMBING BACK INTO THE MID 70S IN THE LOWER ELEVATIONS AND
MID 50S TO MID 60S IN THE MOUNTAINS. THIS WILL BE SLIGHTLY ABOVE
NORMAL. A LARGE UPPER TROUGH WILL THEN SWING DOWN FROM THE GULF OF
ALASKA GOING INTO THE EXTENDED PERIOD WITH COOLER CONDITIONS AND
MORE CHANCES OF PRECIPITATION. 88
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...A RIDGE OF HIGH
PRESSURE SHOULD BRING A WARMER AND MAINLY DRY DAY FOR MONDAY. A
DISTURBANCE WILL APPROACH THE TWO STATE AREA MONDAY NIGHT THAT COULD
SPREAD SOME SHOWERS ALONG THE WA/OR CASCADES. AS A STRONG LOW
PRESSURE SYSTEM DIPS TOWARD THE PACNW TUESDAY...THE SHOWERS SHOULD
MOVE INTO THE REMAINDER OF THE REGION. THE LOW PRESSURE REMAINS
NEARLY STATIONARY AND KEEPS THE CLOUDS AND SHOWERS ALONG WITH THE
COOL TEMPERATURES ACROSS THE TWO STATE AREA THROUGH THURSDAY. THE
LOW IS FORECAST TO DRIFT NORTH AND SOME DRYING IS POSSIBLE FOR
FRIDAY AND SATURDAY ALONG WITH SLIGHTLY WARMER TEMPERATURES.
AVIATION...LCL MVFR CEILINGS WILL OCCUR ON OCCASION AT ALL TAF
SITES. A DISTURBANCE MOVING ACROSS THE REGION WILL BRING SHOWERS TO
PORTIONS OF THE REGION BEFORE SLOWLY MOVING EAST AND CONDITIONS
SHOULD RETURN TO MAINLY VFR BY 02Z. ANOTHER DISTURBANCE WILL
APPROACH THE TWO STATE AREA TOMORROW MORNING AND LOWER CEILINGS WITH
LCL MVFR CONDITIONS MAINLY NEAR TAF SITE KDLS AND KRDM AND KYKM
AFTER 15Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 66 40 67 / 20 20 20 10
ALW 48 68 45 67 / 20 20 20 10
PSC 48 73 45 72 / 10 20 10 10
YKM 44 68 42 70 / 10 20 10 10
HRI 46 70 45 70 / 10 20 10 10
ELN 45 66 43 66 / 10 20 10 10
RDM 37 61 30 60 / 10 30 20 10
LGD 40 62 40 60 / 30 20 20 20
GCD 41 59 36 61 / 20 30 20 10
DLS 48 65 45 65 / 10 20 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SATURDAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
89/97/89
000
FXUS66 KMFR 180312
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
812 PM PDT FRI MAY 17 2013
.DISCUSSION...THE AXIS OF AN UPPER LEVEL TROUGH WILL CONTINUE TO
SHIFT EAST OF THE AREA TONIGHT. EVIDENCE OF THIS IS IN THE LAST
FEW IMAGES OF THE VISIBLE SATELLITE PRIOR TO SUNSET...WHERE STRONG
SUBSIDENCE TO THE LEE OF THE CASCADES LED TO RAPID CLEARING.
THERE STILL MAY BE AN ISOLATED SHOWER FROM NEAR MOUNT SHASTA
EASTWARD TO ALTURAS, THEN UP TO LAKEVIEW THROUGH ABOUT 11PM, BUT
THAT`S ABOUT IT. MOISTURE AROUND 5KFT WILL KEEP SOME CLOUDS ALONG
AND WEST OF THE CASCADES THROUGH THIS EVENING AND OVERNIGHT. THE
NEXT FRONT WILL APPROACH THE COAST TONIGHT, WITH MID LEVEL
CLOUDS RAPIDLY INCREASING WEST OF THE CASCADES BY MORNING. LIGHT
PRECIPITATION WILL LIKELY REACH THE COAST SATURDAY MORNING, THEN
INLAND TO THE CASCADES BY NOON. EAST SIDE AREAS COULD SEE SOME
SHOWERS DEVELOP SATURDAY AFTERNOON. SLIGHT THUNDERSTORM CHANCES
APPEAR TO BE ACROSS THE FAR EAST SIDE...MAINLY FROM THE WARNERS
EASTWARD. CURRENT FORECAST HANDLES THIS WELL SO HAVE MADE NO
CHANGES HERE. SPILDE
&&
.AVIATION...BASED ON THE 18/00Z TAF CYCLE.
VFR CONDITIONS WILL PREVAIL THIS EVENING. AREA OF MVFR CIGS WILL
DEVELOP AT THE COAST LATER TONIGHT AND SPREAD INLAND INTO THE
UMPQUA BASIN LATE TONIGHT AND EARLY SATURDAY. A COLD FRONT WILL
MOVE ONSHORE LATE SATURDAY MORNING...BRINGING ADDITIONAL MVFR CIGS
TO THE COAST AND UMPQUA BASIN. THESE AREAS WILL CLEAR TO VFR
SATURDAY AFTERNOON...BUT MVFR CIGS WILL RETURN TO THE SAME AREAS
SATURDAY NIGHT. STOCKTON
&&
.MARINE...HAVE GONE AHEAD AND ISSUED A GALE WATCH FOR THE SOUTHERN
OUTER MARINE WATERS WITH THE EXPECTED INCREASE IN NORTH WINDS
SUNDAY. STRONG GRADIENT BETWEEN HIGH PRESSURE OFFSHORE AND A
THERMAL TROUGH ALONG THE NORTHERN CALIFORNIA COAST WILL LEAD TO THE
PERIOD OF STRONG NORTH WINDS. IT GOES WITHOUT SAYING THAT VERY STEEP
SHORT PERIOD SEAS WILL ALSO ACCOMPANY THE RAMP UP IN WINDS. WINDS
AND SEAS SHOULD EASE A BIT MONDAY EVENING AS THE HIGH WEAKENS AND
ANOTHER FRONT APPROACHES FROM THE NORTH AND WEST. SPILDE
&&
.PREV DISCUSSION... /ISSUED 311 PM PDT FRI MAY 17 2013/
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...
AN UPPER TROUGH IS EXITING INTO EASTERN OREGON THIS AFTERNOON
WHILE A WEAK SHORTWAVE TROUGH IN A WESTERLY FLOW ALOFT HAS MOVED
INTO WESTERN OREGON. THE RESULT HAS BEEN A DECREASE OF CLOUDS OVER
THE EAST SIDE AND IN NORTHERN CALIFORNIA WHILE THIN BUT WIDESPREAD
MID-LEVEL CLOUDS HAVE PERSISTED IN SOUTHWEST OREGON. THERE WILL BE
A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING THEN LATE IN THE
EVENING THROUGH LATE TONIGHT ANOTHER SHORTWAVE TROUGH WILL
INCREASE CLOUD COVER AND BRING A SLIGHT CHANCE OF SHOWERS TO COOS
AND DOUGLAS COUNTIES.
THIS SHORTWAVE WILL BE IN ADVANCE OF A COLD FRONT. THE COLD FRONT
WILL REACH THE COAST TOWARD NOON ON SATURDAY THEN MOVE EAST
ACROSS OUR AREA INTO EARLY EVENING. THE 12Z GFS QPF FIELD FOR
SATURDAY MORNING LOOKS TOO WET GIVEN THE RELATIVELY SHALLOW HEIGHT
AT WHICH THE AIR MASS WILL BE SATURATED (AROUND 750 MB), WEAK LIFT
WITH OMEGA VALUES OF 1 TO 2 MICROBARS PER SECOND, AND SOUTHERLY
WINDS OVER THE COASTAL WATERS PEAKING AT ONLY ABOUT 18 KT. THAT
SAID, THERE IS A HIGH PROBABILITY OF LIGHT RAIN DURING THE
AFTERNOON AND EVENING WEST AND NORTH OF GRANTS PASS WITH A SLIGHT
CHANCE TO CHANCE ACROSS THE REST OF OUR AREA. THE FRONT WILL ALSO
CREATE BREEZY AFTERNOON AND EVENING NORTHWEST WINDS. WINDS WILL BE
STRONGEST EAST OF THE CASCADES WITH GUSTS UP TO 30 MPH. TOWARD
PEAK HEATING IN THE LATE AFTERNOON, THE FRONT IS EXPECTED TO BE
EAST OF THE CASCADES WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER
THE HIGHER TERRAIN OF EASTERN LAKE AND EASTERN MODOC COUNTIES. THE
COLD FRONT WILL BE THE MAIN FEATURE, BUT A COUPLE OF SHORTWAVES
WILL FOLLOW IN A NORTHWEST FLOW BEHIND THE FRONT SATURDAY NIGHT
AND CONTINUE A SLIGHT CHANCE TO CHANCE OF LIGHT SHOWERS.
LOW LEVEL CLOUDS WILL LINGER AT THE COAST AND IN THE UMPQUA BASIN
SUNDAY MORNING BUT CONDITIONS WILL BE IMPROVING WITH A HIGH
PRESSURE RIDGE CENTERED OFFSHORE FROM CALIFORNIA BUILDING TOWARD
OUR AREA. WINDS WILL TURN TO NORTH TO NORTHEAST AND THE AIR MASS
WILL BE DRYING SUNDAY INTO SUNDAY NIGHT. THIS WILL LEAD TO
CLEARING SKIES...INCLUDING AT THE COAST WITH HIGHS RETURNING TO
NEAR NORMAL EXCEPT ABOUT 10 DEGREES ABOVE NORMAL NEAR BROOKINGS.
THE RIDGE WILL CONTINUE TO INFLUENCE OUR WEATHER ON MONDAY WITH
THE 2-DAY WARMING TREND RESULTING IN HIGH TEMPERATURES A FEW TO
SEVERAL DEGREES ABOVE NORMAL. THE GFS INDICATES HIGH CLOUDS
INCREASING MONDAY AFTERNOON AS THE FIRST SIGN OF A SIGNIFICANT
CHANGE IN THE WEATHER PATTERN. A COLD UPPER LOW WILL BE MOVING
SOUTH TO SOUTHEAST ALONG THE WEST COAST OF CANADA WITH THE FIRST
IN A SERIES OF ASSOCIATED DISTURBANCES APPROACHING THE OREGON
COAST EARLY TUESDAY MORNING.
LONG TERM...TUESDAY, MAY 21ST THROUGH SATURDAY MORNING, MAY 25TH...
MODEL GUIDANCE AGREES WELL ON A DEEP LOW PRESSURE SYSTEM OF 540
DECAMETERS AT THE 500 MILLIBAR LEVEL BEING LOCATED OFF OF THE
COAST OF BRITISH COLUMBIA AT THE BEGINNING OF THIS PERIOD. THIS
PARENT LOW WILL DRIVE A COLD FRONT THROUGH THE FORECAST AREA ON
TUESDAY YIELDING BREEZY CONDITIONS AND BRINGING A SHARP HIGH
TEMPERATURE DROP OF 10 TO 20 DEGREES FOR HIGHS TUESDAY AFTERNOON
AS COMPARED TO MONDAY AFTERNOON. MOST OF THE PRECIPITATION WILL BE
LOCATED OVER NORTHWESTERN PORTIONS OF THE FORECAST AREA ON
TUESDAY.
TUESDAY NIGHT THROUGH SATURDAY THE PARENT LOW AT 500MB WILL MOVE
INTO THE PACIFIC NORTHWEST, BUT HOW FAR SOUTH THE LOW MAKES IT,
HOW STRONG IT IS WHEN IT ARRIVES, AND HOW LONG IT LINGERS ARE
ALL STILL LOWER CONFIDENCE ITEMS IN THE FORECAST RIGHT NOW. THE
GENERAL CONSENSUS IS THAT THE INFLUENCE OF THE LOW WILL LEAD TO
TEMPERATURES ABOUT 10 DEGREES BELOW NORMAL FOR HIGHS THROUGH THE
PERIOD WITH A CHANCE FOR SHOWERS ACROSS THE AREA, MOST LIKELY ON
WEDNESDAY THROUGH FRIDAY, AND MOST LIKELY OVER THE MOUNTAINS, THE
COAST, AND UMPQUA BASIN. ANY PERIODS OF CLEARING AT NIGHT COULD
CERTAINLY YIELD FROST OR FREEZE CONCERNS NEAR AND EAST OF THE
CASCADES TO INCLUDE THE SHASTA VALLEY.
MODEL UNCERTAINTY TOOLS AND RAW MODEL FIELDS DO INDEED INDICATE
ANOMALOUSLY COLD CONDITIONS FOR THE MIDDLE TO THE END OF THE WEEK.
ON THURSDAY THE GFS MODEL LIFTS THE PARENT LOW BACK TO THE
NORTH, INTO INTERIOR BRITISH COLUMBIA THROUGH THE EARLY PART OF
THE WEEKEND. THE ECMWF AND THE NAEFS ENSEMBLE INSTEAD TRACK THE
LOW SOUTHWARD ALONG THE COAST, AND THEN INTO NORTHERN CALIFORNIA
FROM THURSDAY INTO FRIDAY.THE GFS DOES HAVE A WEAKER RENDITION OF
SECONDARY LOW PRESSURE OVER OR NEAR THE SAME AREA AS THE ECMWF
PARENT LOW IN THE THURSDAY THROUGH FRIDAY TIME FRAME, BUT NOT
NEARLY AS STRONG AS THE ECMWF. SINCE THERE APPEARS TO BE A FAIR
AMOUNT OF SPREAD ON THE DETAILS, BUT MORE DATA SUGGESTING THE
ECMWF IS LIKELY TO BE CLOSER TO WHAT VERIFIES, I`VE KEPT ENHANCED
PROBABILITIES OF PRECIPITATION AND COOL TEMPERATURES IN CENTERED
ON THURSDAY. THUS, LEANED ON THE ECMWF SIDE OF CONSENSUS. THIS
MEANS THAT IT WILL BE UNSEASONABLY COOL LATE NEXT WEEK AND THERE
WILL HIGHER MOUNTAIN SNOWFALL AND VALLEY RAINS. EXPECT DETAILS TO
BECOME CLEARER AS EARLY AS TOMORROW. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...GALE WATCH FROM SUNDAY AFTERNOON THROUGH
MONDAY EVENING FOR PZZ376.
HAZARDOUS SEAS WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR PZZ376.
$$
MAS/MAS/JRS
000
FXUS66 KPQR 180305
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
800 PM PDT FRI MAY 17 2013
.SYNOPSIS...SCATTERED SHOWERS WILL SHIFT INTO THE CASCADES THIS
EVENING AS WEAK SURFACE HIGH PRESSURE BUILDS INTO OREGON AND SW
WASHINGTON. THE NEXT PACIFIC SYSTEM WILL MOVE IN FOR SATURDAY...
BRINGING A PERIOD OF STEADY LIGHT RAIN SATURDAY FOLLOWED BY
DECREASING SHOWERS SATURDAY NIGHT AND SUNDAY. DRIER WEATHER IS
EXPECTED SUN NIGHT/MON... BUT IT IS LOOKING MORE LIKELY THAT A COOL
AND UNSETTLED PATTERN WILL SET UP OVER THE PACIFIC NORTHWEST FOR THE
MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...THE BACK EDGE OF SLOW MOVING
SHOWER ACTIVITY HAS SHIFTED INTO THE FOOTHILLS AND CASCADES AS HIGH
PRESSURE NOSES INTO NW OREGON AND SW WASHINGTON. HIGH PRESSURE WILL
REMAIN IN PLACE FOR THE REMAINDER OF THE EVENING AND INTO THE EARLY
OVERNIGHT HOURS...THUS EXPECT MOST AREAS OUTSIDE OF THE CASCADES AND
EVENTUALLY THE COAST TO REMAIN DRY UNTIL LATE TONIGHT.
A GRADUAL END TO SHOWER ACTIVITY HAS OCCURRED BUT MANY AREAS WILL
REMAIN MOSTLY CLOUDY DUE TO THE MOIST LOW LEVEL AIR MASS. THE
EXCEPTION WILL BE IN LEE OF THE COAST RANGE FOR THE REMAINDER OF THE
EVENING. NAM CROSS SECTIONS THROUGH THE WILLAMETTE VALLEY SEEM TO
SUPPORT THIS THINKING. EITHER WAY...IT WILL NOT BE LONG BEFORE HIGHER
CLOUDS BEGIN TO MOVE IN AHEAD OF OUR NEXT SYSTEM NOW SHOWN INSIDE
130W ON IR/WV SATELLITE IMAGERY. KMD
REST OF THE SHORT TERM FORECAST DISCUSSION UNCHANGED...STILL LOOKS
LIKE A DECENT CHANCE FOR RAIN THROUGHOUT THE DISTRICT SATURDAY AS
THAT MODEST FRONTAL SYSTEM MOVES ONSHORE. THERE WILL BE SOME WEAK
ISENTROPIC LIFT AHEAD OF THIS SYSTEM...SO JUST ABOUT EVERYONE SHOULD
GET SOME LIGHT RAIN. ONLY MODEST OROGRAPHIC ENHANCEMENT WITH 15-25
KT SW 850 MB WINDS...SO EXPECT RAIN TOTALS TO RANGE FROM 0.10-0.25
INCH IN THE VALLEYS AND 0.50 TO LOCALLY 1 INCH IN THE HIGHER
TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH A FEW
LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER NEAR OR A LITTLE BELOW NORMAL THROUGH THE
WEEKEND. SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES. MONDAY APPEARS
TO BE A DRIER DAY WITH MILD TEMPS AS A SHORTWAVE RIDGE MOVES ACROSS
THE PACIFIC NORTHWEST...BUT THIS WILL BE BRIEF AS THE NEXT SYSTEM
LOOMS FOR TUESDAY AND MIDWEEK. WEAGLE
.LONG TERM...MONDAY EVENING THROUGH FRIDAY...COLD CLOSED LOW
PRESSURE SYSTEM WILL PUSH ONSHORE MONDAY NIGHT...BRINGING RAIN AND
MUCH COOLER TEMPERATURES TO THE AREA. THIS LOW WILL LINGER OVER THE
PAC NW TUESDAY AND MUCH OF THE DAY WEDNESDAY...WITH RECORD LOW
MAXIMUM TEMPERATURES POSSIBLE ON WEDNESDAY. BY THURSDAY MODELS
DISAGREE ON WHERE THE LOW WILL PROPAGATE...BUT THE OVERALL TREND IS
FOR SHOWERY AND COOL CONDITIONS TO PERSIST THROUGH THE END OF THE
WEEK. BURGESS
&&
.AVIATION...AIR MASS STABILIZING THIS EVENING...AS MORE STABLE AIR
MASS SPREADS INTO THE REGION. SKIES REMAIN VFR THIS EVENING...WITH
WORST CONDITIONS AGAINST THE CASCADES. AS FRONT APPROACHES...CIGS
GRADUALLY LOWER LATE TONIGHT...WITH MVFR AND OCCASIONAL RAIN
INCREASING BETWEEN 10Z AND 14Z SAT. FRONT IS FAST MOVING...SO
RETURN TO VFR LIKELY BETWEEN 19Z AND 22Z...FIRST ON COAST AND
LATER INLAND AS THE FRONT SWEEPS EAST OF THE CASCADES BY MID
AFTERNOON.
KPDX AND APPROACHES...VFR TONIGHT. AREAS OF MVFR CIGS DOWN NEAR
2500 FT INCREASE BETWEEN 12Z AND 15Z. MVFR WITH RAIN DOMINATES
SAT AM. FRONT WILL PUSH ACROSS KPDX OPS AREA BETWEEN 20Z AND
22Z...WITH RETURN TO VFR WITH SCATTERED SHOWERS.ROCKEY.
&&
.MARINE...WINDS WILL GRADUALLY TURN MORE SOUTHERLY TONIGHT AS
ANOTHER FRONT APPROACHES. THIS FRONT WILL PUSH ACROSS THE COASTAL
WATERS SAT AM...THEN INLAND IN THE AFTERNOON. WINDS NOT ALL THAT
IMPRESSIVE BUT SEEMS THAT BE ENOUGH GRADIENT TO POP GUSTS 20 TO 25
KT SAT AM. SO WILL PUT UP SMALL CRAFT ADVISORY FOR THAT TIME
FRAME. OTHERWISE...WINDS TURN W TO NW BEHIND THE FRONT IN THE
AFTERNOON AND BEGIN TO EASE.
HIGH PRES WILL BUILD OVER THE NE PAC FOR SUN INTO EARLY NEXT WEEK.
THIS WILL KEEP NW WINDS 10 TO 15 KT THROUGH MUCH OF THE COMING
WEEK...THOUGH MAY BRIEFLY GET 20 TO 25 KT GUSTS MON AFTERNOON INTO
THE EVENING.
SEAS REMAIN AT 5 TO 6 FT FOR INTO EARLY NEXT WEEK. MAY SEE SEAS
BUILD UP AND BECOME CHOPPY AT TIMES WITH THE BRISK NW WINDS ON THE
CENTRAL OREGON COASTAL WATERS NEXT WEEK. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS SAT AM ON ALL COASTAL WATERS.
&&
$$
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.
000
FXUS65 KBOI 180232
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
832 PM MDT FRI MAY 17 2013
.DISCUSSION...A NEGATIVELY TILTED UPPER LEVEL TROUGH AXIS FROM
AROUND PORTLAND OREGON TO ELKO NEVADA AT 8 PM BROUGHT LARGE SCALE
LIFT ACROSS SE OREGON AND SW IDAHO THIS AFTERNOON. ISOLATED
THUNDERSTORMS EXTENDED FROM NORTH MALHEUR COUNTY TO CENTRAL OWYHEE
COUNTY AND WERE LIFTING TOWARDS THE NORTHEAST AT 10-15 MPH. THIS
TROUGH AXIS WILL SPREAD THROUGH SW IDAHO TONIGHT AND LIKELY KEEP
ISOLATED THUNDERSTORMS GOING WITH IT...UNTIL AROUND MIDNIGHT
INCLUDING FOR THE TREASURE VALLEY. EVENING WEATHER BALLOON
SOUNDING SHOWED INSTABILITY OF -1.4C LI AND 341 J/KG CAPE ALONG
WITH LIGHT SHEAR OF LESS THAN 20 M/S...SO STORMS LOOK TO REMAIN
PULSE-LIKE WITH LOCAL GUSTS OF 30 MPH BUT UP TO 45 MPH...SUCH AS
OCCURRED AT GRASSY MOUNTAIN RAWS IN THE LATE AFTERNOON. SMALL HAIL
WAS REPORTED WITH ANOTHER STRONGER LOOKING CELL NEAR BUHL AND A
MENACING LOOKING SHELF CLOUD AND RAIN OR RAIN AND HAIL SHAFT WAS
SHARED VIA FACEBOOK FROM THE TWIN FALLS AREA. FORECAST IS ON TRACK
WITH NO UPDATES EXPECTED.
&&
.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY SOUTH AND
WEST OF THE SNAKE RIVER PLAIN AT 02Z WILL PUSH EAST-NORTHEAST THIS
EVENING. EXPECT BRIEF MVFR CEILINGS...HEAVY RAIN AND GUSTY WINDS
WITH THESE STORMS. OTHERWISE...SCATTERED TO BROKEN CLOUDS DECK
GENERALLY AT 5K-7K FEET ASL. WEST-NORTHWEST SURFACE WINDS AT 10-15
KTS. WEST WINDS ALOFT UP TO 20 KTS AT 10K FEET MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY AFTERNOON - MAINLY ACROSS SE OREGON AND
HIGHER TERRAIN OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS
CONFINED TO THE CENTRAL IDAHO MOUNTAINS AND EASTWARD.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH SUNDAY...HEATING OF THE DAY COMBINED
WITH MOISTURE ASSOCIATED WITH AN UPPER TROUGH WAS RESULTING IN
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. INSTABILITY WAS MARGINAL
TO SUPPORT THUNDERSTORMS...ALTHOUGH ENOUGH TO KEEP ISOLATED COVERAGE
IN THE FORECAST THROUGH THIS EVENING. DRIER STABLE AIR WILL
TEMPORARILY MOVE INTO SE OREGON LATE TONIGHT AND SATURDAY MORNING
WITH A SHORT WAVE UPPER RIDGE. ANOTHER TROUGH WILL THEN MOVE INTO
THE PACNW SATURDAY AFTERNOON...THEN SLOWLY WORK EASTWARD ACROSS THE
AREA THROUGH SUNDAY. THE SECOND TROUGH WILL BRING MORE MOISTURE AND
A CHANCE OF MOUNTAIN/SLIGHT CHANCE OF VALLEY SHOWERS...ALTHOUGH THE
SYSTEM WILL BE WEAKER AND WITH LESS MOISTURE. SNOW LEVELS WILL LOWER
TO AROUND 7500 FEET MSL WITH LIGHT SNOW ACCUMULATIONS POSSIBLE ON
THE PEAKS. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL THROUGH
THE WEEKEND. BREEZY NORTHWEST WINDS ARE EXPECTED SATURDAY AFTERNOON
WITH A LITTLE STRONGER WINDS EXPECTED SUNDAY AFTERNOON...ESPECIALLY
IN THE UPPER TREASURE VALLEY AND WESTERN MAGIC VALLEY.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...A SHORTWAVE RIDGE WILL
BUILD INTO THE AREA FROM THE WEST EARLY MONDAY...ALLOWING SKIES TO
CLEAR AND TEMPS TO RISE TO NEAR NORMAL VALUES MONDAY AFTERNOON. AS A
DEEP LOW PRESSURE SYSTEM SLIDES SOUTHWARD INTO THE PACIFIC NORTHWEST
ON TUESDAY...SOUTHWEST FLOW WILL PICK UP OVER THE INTERMOUNTAIN WEST
WHICH WILL DRIVE THE AFTERNOON HIGH TEMPERATURES TO AROUND 5 DEGREES
ABOVE NORMAL. THE LOW WILL CONTINUE TO MOVE SOUTHWARD...BRINGING A
STRONG SURFACE COLD FRONT THROUGH SE OREGON AND SW IDAHO LATE TUESDAY
NIGHT. EXPECT HIGH TEMPS ON WEDNESDAY TO BE NEARLY 20 DEGREES COOLER
THAN TUESDAY. THE LOW PRESSURE SYSTEM WILL STALL OUT OVER THE PAC NW
THROUGH THE END OF THE WEEK...KEEPING CONDITIONS COOL AND UNSETTLED.
MOST OF THE AVAILABLE MOISTURE LOOKS TO BE ON THE NORTHERN HALF OF
THE LOW CIRCULATION...WITH THE SOUTHERN PORTION OF THE LOW AFFECTING
OUR AREA. THUS THE BEST CHANCE FOR SHOWERS WILL BE ACROSS OUR
NORTHERN AND WESTERN MOUNTAIN ZONES.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...VM
AVIATION.....JS
PREV SHORT TERM...BW
PREV LONG TERM....CB
000
FXUS66 KMFR 172214 CCA
AFDMFR
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MEDFORD OR
311 PM PDT FRI MAY 17 2013
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...
AN UPPER TROUGH IS EXITING INTO EASTERN OREGON THIS AFTERNOON
WHILE A WEAK SHORTWAVE TROUGH IN A WESTERLY FLOW ALOFT HAS MOVED
INTO WESTERN OREGON. THE RESULT HAS BEEN A DECREASE OF CLOUDS OVER
THE EAST SIDE AND IN NORTHERN CALIFORNIA WHILE THIN BUT WIDESPREAD
MID-LEVEL CLOUDS HAVE PERSISTED IN SOUTHWEST OREGON. THERE WILL BE
A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING THEN LATE IN THE
EVENING THROUGH LATE TONIGHT ANOTHER SHORTWAVE TROUGH WILL
INCREASE CLOUD COVER AND BRING A SLIGHT CHANCE OF SHOWERS TO COOS
AND DOUGLAS COUNTIES.
THIS SHORTWAVE WILL BE IN ADVANCE OF A COLD FRONT. THE COLD FRONT
WILL REACH THE COAST TOWARD NOON ON SATURDAY THEN MOVE EAST
ACROSS OUR AREA INTO EARLY EVENING. THE 12Z GFS QPF FIELD FOR
SATURDAY MORNING LOOKS TOO WET GIVEN THE RELATIVELY SHALLOW HEIGHT
AT WHICH THE AIR MASS WILL BE SATURATED (AROUND 750 MB), WEAK LIFT
WITH OMEGA VALUES OF 1 TO 2 MICROBARS PER SECOND, AND SOUTHERLY
WINDS OVER THE COASTAL WATERS PEAKING AT ONLY ABOUT 18 KT. THAT
SAID, THERE IS A HIGH PROBABILITY OF LIGHT RAIN DURING THE
AFTERNOON AND EVENING WEST AND NORTH OF GRANTS PASS WITH A SLIGHT
CHANCE TO CHANCE ACROSS THE REST OF OUR AREA. THE FRONT WILL ALSO
CREATE BREEZY AFTERNOON AND EVENING NORTHWEST WINDS. WINDS WILL BE
STRONGEST EAST OF THE CASCADES WITH GUSTS UP TO 30 MPH. TOWARD
PEAK HEATING IN THE LATE AFTERNOON, THE FRONT IS EXPECTED TO BE
EAST OF THE CASCADES WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER
THE HIGHER TERRAIN OF EASTERN LAKE AND EASTERN MODOC COUNTIES. THE
COLD FRONT WILL BE THE MAIN FEATURE, BUT A COUPLE OF SHORTWAVES
WILL FOLLOW IN A NORTHWEST FLOW BEHIND THE FRONT SATURDAY NIGHT
AND CONTINUE A SLIGHT CHANCE TO CHANCE OF LIGHT SHOWERS.
LOW LEVEL CLOUDS WILL LINGER AT THE COAST AND IN THE UMPQUA BASIN
SUNDAY MORNING BUT CONDITIONS WILL BE IMPROVING WITH A HIGH
PRESSURE RIDGE CENTERED OFFSHORE FROM CALIFORNIA BUILDING TOWARD
OUR AREA. WINDS WILL TURN TO NORTH TO NORTHEAST AND THE AIR MASS
WILL BE DRYING SUNDAY INTO SUNDAY NIGHT. THIS WILL LEAD TO
CLEARING SKIES...INCLUDING AT THE COAST WITH HIGHS RETURNING TO
NEAR NORMAL EXCEPT ABOUT 10 DEGREES ABOVE NORMAL NEAR BROOKINGS.
THE RIDGE WILL CONTINUE TO INFLUENCE OUR WEATHER ON MONDAY WITH
THE 2-DAY WARMING TREND RESULTING IN HIGH TEMPERATURES A FEW TO
SEVERAL DEGREES ABOVE NORMAL. THE GFS INDICATES HIGH CLOUDS
INCREASING MONDAY AFTERNOON AS THE FIRST SIGN OF A SIGNIFICANT
CHANGE IN THE WEATHER PATTERN. A COLD UPPER LOW WILL BE MOVING SOUTH
TO SOUTHEAST ALONG THE WEST COAST OF CANADA WITH THE FIRST IN A
SERIES OF ASSOCIATED DISTURBANCES APPROACHING THE OREGON COAST
EARLY TUESDAY MORNING.
.LONG TERM...TUESDAY, MAY 21ST THROUGH SATURDAY MORNING, MAY 25TH...
MODEL GUIDANCE AGREES WELL ON A DEEP LOW PRESSURE SYSTEM OF 540
DECAMETERS AT THE 500 MILLIBAR LEVEL BEING LOCATED OFF OF THE
COAST OF BRITISH COLUMBIA AT THE BEGINNING OF THIS PERIOD. THIS
PARENT LOW WILL DRIVE A COLD FRONT THROUGH THE FORECAST AREA ON
TUESDAY YIELDING BREEZY CONDITIONS AND BRINGING A SHARP HIGH
TEMPERATURE DROP OF 10 TO 20 DEGREES FOR HIGHS TUESDAY AFTERNOON
AS COMPARED TO MONDAY AFTERNOON. MOST OF THE PRECIPITATION WILL BE
LOCATED OVER NORTHWESTERN PORTIONS OF THE FORECAST AREA ON
TUESDAY.
TUESDAY NIGHT THROUGH SATURDAY THE PARENT LOW AT 500MB WILL MOVE
INTO THE PACIFIC NORTHWEST, BUT HOW FAR SOUTH THE LOW MAKES IT, HOW
STRONG IT IS WHEN IT ARRIVES, AND HOW LONG IT LINGERS ARE ALL STILL
LOWER CONFIDENCE ITEMS IN THE FORECAST RIGHT NOW. THE GENERAL
CONSENSUS IS THAT THE INFLUENCE OF THE LOW WILL LEAD TO TEMPERATURES
ABOUT 10 DEGREES BELOW NORMAL FOR HIGHS THROUGH THE PERIOD WITH A
CHANCE FOR SHOWERS ACROSS THE AREA, MOST LIKELY ON WEDNESDAY THROUGH
FRIDAY, AND MOST LIKELY OVER THE MOUNTAINS, THE COAST, AND UMPQUA
BASIN. ANY PERIODS OF CLEARING AT NIGHT COULD CERTAINLY YIELD FROST
OR FREEZE CONCERNS NEAR AND EAST OF THE CASCADES TO INCLUDE THE
SHASTA VALLEY.
MODEL UNCERTAINTY TOOLS AND RAW MODEL FIELDS DO INDEED INDICATE
ANOMALOUSLY COLD CONDITIONS FOR THE MIDDLE TO THE END OF THE WEEK.
ON THURSDAY THE GFS MODEL LIFTS THE PARENT LOW BACK TO THE NORTH,
INTO INTERIOR BRITISH COLUMBIA THROUGH THE EARLY PART OF THE
WEEKEND. THE ECMWF AND THE NAEFS ENSEMBLE INSTEAD TRACK THE LOW
SOUTHWARD ALONG THE COAST, AND THEN INTO NORTHERN CALIFORNIA FROM
THURSDAY INTO FRIDAY.THE GFS DOES HAVE A WEAKER RENDITION OF
SECONDARY LOW PRESSURE OVER OR NEAR THE SAME AREA AS THE ECMWF
PARENT LOW IN THE THURSDAY THROUGH FRIDAY TIME FRAME, BUT NOT NEARLY
AS STRONG AS THE ECMWF. SINCE THERE APPEARS TO BE A FAIR AMOUNT OF
SPREAD ON THE DETAILS, BUT MORE DATA SUGGESTING THE ECMWF IS LIKELY TO
BE CLOSER TO WHAT VERIFIES, I`VE KEPT ENHANCED PROBABILITIES OF
PRECIPITATION AND COOL TEMPERATURES IN CENTERED ON THURSDAY. THUS,
LEANED ON THE ECMWF SIDE OF CONSENSUS. THIS MEANS THAT IT WILL BE
UNSEASONABLY COOL LATE NEXT WEEK AND THERE WILL HIGHER MOUNTAIN
SNOWFALL AND VALLEY RAINS. EXPECT DETAILS TO BECOME CLEARER AS EARLY
AS TOMORROW. BTL
&&
.AVIATION...
BASED ON THE 17/18Z TAF CYCLE.
VFR CONDITIONS WILL PREVAIL THIS EVENING. OVERNIGHT SOME MVFR
CEILINGS ARE POSSIBLE OVER PORTIONS OF THE WEST SIDE. A COLD FRONT
WILL MOVE ONTO THE COAST ON SATURDAY MORNING WITH MVFR TO IFR
CEILINGS DEVELOPING FROM ROSEBURG WESTWARD. SHOWERS WILL SPREAD
ACROSS THE AREA ON SATURDAY WITH GUSTY WINDS. MVFR CEILINGS WILL
OCCUR IN THE AFTERNOON ALONG AND NEAR THE COASTAL MOUNTAINS,
CASCADES, AND IN THE UMPQUA BASIN. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
DW/BTL/JRS
000
FXUS66 KMFR 172210
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
310 PM PDT FRI MAY 17 2013
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...
AN UPPER TROUGH IS EXITING INTO EASTERN OREGON THIS AFTERNOON
WHILE A WEAK SHORTWAVE TROUGH IN A WESTERLY FLOW ALOFT HAS MOVED
INTO WESTERN OREGON. THE RESULT HAS BEEN A DECREASE OF CLOUDS OVER
THE EAST SIDE AND IN NORTHERN CALIFORNIA WHILE THIN BUT WIDESPREAD
MID-LEVEL CLOUDS HAVE PERSISTED IN SOUTHWEST OREGON. THERE WILL BE
A BRIEF PERIOD OF SHORTWAVE RIDGING THIS EVENING THEN LATE IN THE
EVENING THROUGH LATE TONIGHT ANOTHER SHORTWAVE TROUGH WILL
INCREASE CLOUD COVER AND BRING A SLIGHT CHANCE OF SHOWERS TO COOS
AND DOUGLAS COUNTIES.
THIS SHORTWAVE WILL BE IN ADVANCE OF A COLD FRONT. THE COLD FRONT
WILL REACH THE COAST TOWARD NOON ON SATURDAY THEN MOVE EAST
ACROSS OUR AREA INTO EARLY EVENING. THE 12Z GFS QPF FIELD FOR
SATURDAY MORNING LOOKS TOO WET GIVEN THE RELATIVELY SHALLOW HEIGHT
AT WHICH THE AIR MASS WILL BE SATURATED (AROUND 750 MB), WEAK LIFT
WITH OMEGA VALUES OF 1 TO 2 MICROBARS PER SECOND, AND SOUTHERLY
WINDS OVER THE COASTAL WATERS PEAKING AT ONLY ABOUT 18 KT. THAT
SAID, THERE IS A HIGH PROBABILITY OF LIGHT RAIN DURING THE
AFTERNOON AND EVENING WEST AND NORTH OF GRANTS PASS WITH A SLIGHT
CHANCE TO CHANCE ACROSS THE REST OF OUR AREA. TOWARD PEAK HEATING
IN THE LATE AFTERNOON, THE FRONT IS EXPECTED TO BE EAST OF THE
CASCADES WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER THE HIGHER
TERRAIN OF EASTERN LAKE AND EASTERN MODOC COUNTIES. THE COLD FRONT
WILL BE THE MAIN FEATURE, BUT A COUPLE OF SHORTWAVES WILL FOLLOW
IN A NORTHWEST FLOW BEHIND THE FRONT SATURDAY NIGHT AND CONTINUE A
SLIGHT CHANCE TO CHANCE OF LIGHT SHOWERS.
LOW LEVEL CLOUDS WILL LINGER AT THE COAST AND IN THE UMPQUA BASIN
SUNDAY MORNING BUT CONDITIONS WILL BE IMPROVING WITH A HIGH
PRESSURE RIDGE CENTERED OFFSHORE FROM CALIFORNIA BUILDING TOWARD
OUR AREA. WINDS WILL TURN TO NORTH TO NORTHEAST AND THE AIR MASS
WILL BE DRYING SUNDAY INTO SUNDAY NIGHT. THIS WILL LEAD TO
CLEARING SKIES...INCLUDING AT THE COAST WITH HIGHS RETURNING TO
NEAR NORMAL EXCEPT ABOUT 10 DEGREES ABOVE NORMAL NEAR BROOKINGS.
THE RIDGE WILL CONTINUE TO INFLUENCE OUR WEATHER ON MONDAY WITH
THE 2-DAY WARMING TREND RESULTING IN HIGH TEMPERATURES A FEW TO
SEVERAL DEGREES ABOVE NORMAL. THE GFS INDICATES HIGH CLOUDS
INCREASING MONDAY AFTERNOON AS THE FIRST SIGN OF A SIGNIFICANT
CHANGE IN THE WEATHER PATTERN. A COLD UPPER LOW WILL BE MOVING SOUTH
TO SOUTHEAST ALONG THE WEST COAST OF CANADA WITH THE FIRST IN A
SERIES OF ASSOCIATED DISTURBANCES APPROACHING THE OREGON COAST
EARLY TUESDAY MORNING.
.LONG TERM...TUESDAY, MAY 21ST THROUGH SATURDAY MORNING, MAY 25TH...
MODEL GUIDANCE AGREES WELL ON A DEEP LOW PRESSURE SYSTEM OF 540
DECAMETERS AT THE 500 MILLIBAR LEVEL BEING LOCATED OFF OF THE
COAST OF BRITISH COLUMBIA AT THE BEGINNING OF THIS PERIOD. THIS
PARENT LOW WILL DRIVE A COLD FRONT THROUGH THE FORECAST AREA ON
TUESDAY YIELDING BREEZY CONDITIONS AND BRINGING A SHARP HIGH
TEMPERATURE DROP OF 10 TO 20 DEGREES FOR HIGHS TUESDAY AFTERNOON
AS COMPARED TO MONDAY AFTERNOON. MOST OF THE PRECIPITATION WILL BE
LOCATED OVER NORTHWESTERN PORTIONS OF THE FORECAST AREA ON
TUESDAY.
TUESDAY NIGHT THROUGH SATURDAY THE PARENT LOW AT 500MB WILL MOVE
INTO THE PACIFIC NORTHWEST, BUT HOW FAR SOUTH THE LOW MAKES IT, HOW
STRONG IT IS WHEN IT ARRIVES, AND HOW LONG IT LINGERS ARE ALL STILL
LOWER CONFIDENCE ITEMS IN THE FORECAST RIGHT NOW. THE GENERAL
CONSENSUS IS THAT THE INFLUENCE OF THE LOW WILL LEAD TO TEMPERATURES
ABOUT 10 DEGREES BELOW NORMAL FOR HIGHS THROUGH THE PERIOD WITH A
CHANCE FOR SHOWERS ACROSS THE AREA, MOST LIKELY ON WEDNESDAY THROUGH
FRIDAY, AND MOST LIKELY OVER THE MOUNTAINS, THE COAST, AND UMPQUA
BASIN. ANY PERIODS OF CLEARING AT NIGHT COULD CERTAINLY YIELD FROST
OR FREEZE CONCERNS NEAR AND EAST OF THE CASCADES TO INCLUDE THE
SHASTA VALLEY.
MODEL UNCERTAINTY TOOLS AND RAW MODEL FIELDS DO INDEED INDICATE
ANOMALOUSLY COLD CONDITIONS FOR THE MIDDLE TO THE END OF THE WEEK.
ON THURSDAY THE GFS MODEL LIFTS THE PARENT LOW BACK TO THE NORTH,
INTO INTERIOR BRITISH COLUMBIA THROUGH THE EARLY PART OF THE
WEEKEND. THE ECMWF AND THE NAEFS ENSEMBLE INSTEAD TRACK THE LOW
SOUTHWARD ALONG THE COAST, AND THEN INTO NORTHERN CALIFORNIA FROM
THURSDAY INTO FRIDAY.THE GFS DOES HAVE A WEAKER RENDITION OF
SECONDARY LOW PRESSURE OVER OR NEAR THE SAME AREA AS THE ECMWF
PARENT LOW IN THE THURSDAY THROUGH FRIDAY TIME FRAME, BUT NOT NEARLY
AS STRONG AS THE ECMWF. SINCE THERE APPEARS TO BE A FAIR AMOUNT OF
SPREAD ON THE DETAILS, BUT MORE DATA SUGGESTING THE ECMWF IS LIKELY TO
BE CLOSER TO WHAT VERIFIES, I`VE KEPT ENHANCED PROBABILITIES OF
PRECIPITATION AND COOL TEMPERATURES IN CENTERED ON THURSDAY. THUS,
LEANED ON THE ECMWF SIDE OF CONSENSUS. THIS MEANS THAT IT WILL BE
UNSEASONABLY COOL LATE NEXT WEEK AND THERE WILL HIGHER MOUNTAIN
SNOWFALL AND VALLEY RAINS. EXPECT DETAILS TO BECOME CLEARER AS EARLY
AS TOMORROW. BTL
&&
.AVIATION...
BASED ON THE 17/18Z TAF CYCLE.
VFR CONDITIONS WILL PREVAIL THIS EVENING. OVERNIGHT SOME MVFR
CEILINGS ARE POSSIBLE OVER PORTIONS OF THE WEST SIDE. A COLD FRONT
WILL MOVE ONTO THE COAST ON SATURDAY MORNING WITH MVFR TO IFR
CEILINGS DEVELOPING FROM ROSEBURG WESTWARD. SHOWERS WILL SPREAD
ACROSS THE AREA ON SATURDAY WITH GUSTY WINDS. MVFR CEILINGS WILL
OCCUR IN THE AFTERNOON ALONG AND NEAR THE COASTAL MOUNTAINS,
CASCADES, AND IN THE UMPQUA BASIN. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
DW/BTL/JRS
000
FXUS66 KPQR 172141
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
240 PM PDT FRI MAY 17 2013
.SYNOPSIS...SCATTERED SHOWERS WILL GRADUALLY DECREASE THIS EVENING AS
WEAK SURFACE HIGH PRESSURE BUILDS INTO OREGON AND SW WASHINGTON. THE
NEXT PACIFIC SYSTEM WILL MOVE IN FOR SATURDAY...PROBABLY BRINGING A
PERIOD OF STEADY LIGHT RAIN SATURDAY FOLLOWED BY DECREASING SHOWERS
SATURDAY NIGHT AND SUNDAY. DRIER WEATHER IS EXPECTED SUN NIGHT/MON...
BUT IT IS LOOKING MORE LIKELY THAT A COOL AND UNSETTLED PATTERN WILL
SET UP OVER THE PACIFIC NORTHWEST FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...A WEAK UPPER LEVEL TROUGH
CONTINUES TO GENERATE SCATTERED SHOWERS ACROSS THE FORECAST AREA THIS
AFTERNOON. THIS INSTABILITY IS PRETTY MUCH ALL SURFACE BASED BUT VERY
SHALLOW...WITH A CAPPING INVERSION IN PLACE AROUND 10KFT. WHILE THE
SHOWERS ARE NOT DEEP ENOUGH TO PRODUCE LIGHTNING...THE MIXED LAYER IS
STILL MOISTURE RICH. SO THERE STILL COULD BE SOME BRIEF HIT AND MISS
DOWNPOURS THROUGH THE RUSH HOUR COMMUTE.
SUBSIDENCE WILL INCREASE THIS EVENING AS SURFACE HIGH PRESSURE BUILDS
INTO OREGON. THIS SHOULD BRING A GRADUAL END TO SHOWER ACTIVITY BUT
IT WILL PROBABLY REMAIN CLOUDY DUE TO THE MOIST LOW LEVEL AIR MASS.
NAM CROSS SECTIONS THROUGH THE WILLAMETTE VALLEY SEEM TO SUPPORT THIS
THINKING. EITHER WAY...IT WILL NOT BE LONG BEFORE HIGHER CLOUDS BEGIN
TO MOVE IN AHEAD OF OUR NEXT SYSTEM NOW SHOWN APPROACHING 130W ON
IR/WV SATELLITE IMAGERY.
STILL LOOKS LIKE A DECENT CHANCE FOR RAIN THROUGHOUT THE DISTRICT
SATURDAY AS THAT MODEST FRONTAL SYSTEM MOVES ONSHORE. THERE WILL BE
SOME WEAK ISENTROPIC LIFT AHEAD OF THIS SYSTEM...SO JUST ABOUT
EVERYONE SHOULD GET SOME LIGHT RAIN. ONLY MODEST OROGRAPHIC
ENHANCEMENT WITH 15-25 KT SW 850 MB WINDS...SO EXPECT RAIN TOTALS TO
RANGE FROM 0.10-0.25 INCH IN THE VALLEYS AND 0.50 TO LOCALLY 1 INCH
IN THE HIGHER TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH
A FEW LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER NEAR OR A LITTLE BELOW NORMAL THROUGH THE
WEEKEND. SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES. MONDAY APPEARS
TO BE A DRIER DAY WITH MILD TEMPS AS A SHORTWAVE RIDGE MOVES ACROSS
THE PACIFIC NORTHWEST...BUT THIS WILL BE BRIEF AS THE NEXT SYSTEM
LOOMS FOR TUESDAY AND MIDWEEK. WEAGLE
.LONG TERM...MONDAY EVENING THROUGH FRIDAY...COLD CLOSED LOW
PRESSURE SYSTEM WILL PUSH ONSHORE MONDAY NIGHT...BRINGING RAIN AND
MUCH COOLER TEMPERATURES TO THE AREA. THIS LOW WILL LINGER OVER THE
PAC NW TUESDAY AND MUCH OF THE DAY WEDNESDAY...WITH RECORD LOW
MAXIMUM TEMPERATURES POSSIBLE ON WEDNESDAY. BY THURSDAY MODELS
DISAGREE ON WHERE THE LOW WILL PROPAGATE...BUT THE OVERALL TREND IS
FOR SHOWERY AND COOL CONDITIONS TO PERSIST THROUGH THE END OF THE
WEEK. BURGESS
&&
.AVIATION...SHOWER ACTIVITY HAS PICKED UP THIS AFTERNOON DUE TO
AFTERNOON HEATING AND INCREASING ONSHORE FLOW INTO THE COAST RANGE
THIS IS TRIGGERING SHOWERS IN THE ELEVATED MOUNTAIN TERRAIN THAT ARE
DRIFTING INTO THE INTERIOR LOWLANDS. EXPECT THIS SHOWER ACTIVITY
TO CONTINUE THROUGH THE AFTERNOON...ALTHOUGH VFR CONDITIONS ARE
EXPECTED TO CONTINUE. SHOWERS WILL DIMINISH THIS EVENING AS TEMPS
COOL AND THE UPPER LEVEL TROUGH AXIS PUSHES FURTHER EAST OF THE
AREA. MVFR CIGS WILL BEGIN TO SPREAD INTO THE COAST OVERNIGHT...
POTENTIALLY PUSHING INTO SOME INLAND SITES TOWARDS DAYBREAK AS WELL.
A FRONTAL PASSAGE WILL BRING LIGHT RAIN TO THE REGION DURING THE DAY
TOMORROW. EXPECT CONDITIONS WILL BE IN AND OUT OF MVFR THROUGH THE
DAY.
KPDX AND APPROACHES...VFR CIGS THROUGH TONIGHT. SCATTERED SHOWER
ACTIVITY IS EXPECTED THROUGH THE AFTERNOON...BEFORE DIMINISHING THIS
EVENING. THERE IS A CHANCE OF MVFR CIGS BY SUNRISE SATURDAY. A
FRONT WILL PUSH INLAND LATER IN THE MORNING...WITH A MIX OF VFR AND
MVFR EXPECTED THROUGH THE DAY IN LIGHT RAIN. PYLE
&&
.MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS
THROUGH TONIGHT. A FRONTAL BOUNDARY WILL PASS THROUGH THE WATERS
TOMORROW...BRINGING SOME STRONGER PREFRONTAL SW WINDS. THE FCST
MODELS ARE INDICATING THAT GUSTY WINDS WILL NOT BE QUITE WIDESPREAD
OR FREQUENT ENOUGH FOR A SMALL CRAFT ADVISORY. HOWEVER...THERE IS THE
POTENTIAL FOR A BIT OF A COASTAL JET FORMING IN THE NEARSHORE WATERS
DURING THE LATE MORNING/EARLY AFTERNOON HRS. SO A FEW GUSTS UP INTO
THE MID 20 KT RANGE ARE POSSIBLE. NORTHWEST WINDS WILL THEN
PREDOMINATE THE REMAINDER OF THE WEEKEND AND MUCH OF NEXT WEEK. A
SMALL CRAFT ADVISORY MAY BE REQUIRED FOR MONDAY AFTERNOON OR EVENING
TIME FRAME.
SEAS ARE FORECAST TO REMAIN AROUND 5 OR 6 FT FOR SEVERAL DAYS. WE
MAY SEE SEAS REACH 10 FT NEXT WEEK DUE TO THE BRISK NORTHWEST
WINDS. PYLE
&&
.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.
000
FXUS66 KPDT 172123
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
220 PM PDT FRI MAY 17 2013
.SHORT TERM...TONIGHT THROUGH MONDAY...A WEATHER DISTURBANCE
CONTINUES TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON. THERE
WERE LIGHT RAIN SHOWERS REPORTED ACROSS THE BLUE MOUNTAIN FOOTHILLS
AND THE LOWER COLUMBIA BASIN...BUT PRECIPITATION AMOUNTS WERE MAINLY
JUST TRACE AMOUNTS. THE UPPER TROUGH ASSOCIATED WITH THIS SYSTEM IS
NOW LOCATED OVER THE CWA AND IT WILL SLOWLY LIFT OUT TO THE
NORTHEAST TONIGHT. ON SATURDAY ANOTHER WEATHER DISTURBANCE WILL MOVE
INTO THE REGION BRINGING ANOTHER CHANCE OF LIGHT RAIN SHOWERS...
MAINLY TO THE MOUNTAINS...HOWEVER CANNOT RULE OUT A LIGHT SPRINKLE
ELSEWHERE. AGAIN PRECIPITATION AMOUNTS WILL BE VERY LIGHT. THE UPPER
TROUGH WITH THIS NEXT SYSTEM WILL MOVE ACROSS THE CWA LATE SATURDAY
AFTERNOON AND EVENING. BEHIND IT AN UPPER RIDGE WILL BEGIN TO BUILD
INTO THE REGION WITH A DRIER NORTHWEST FLOW ALOFT BEGINNING BY LATE
SUNDAY. THIS UPPER RIDGE WILL PERSIST THROUGH MONDAY EVENING. EXPECT
WARMER TEMPERATURES ON MONDAY AS A RESULT WITH MAXIMUM TEMPERATURE
READINGS CLIMBING BACK INTO THE MID 70S IN THE LOWER ELEVATIONS AND
MID 50S TO MID 60S IN THE MOUNTAINS. THIS WILL BE SLIGHTLY ABOVE
NORMAL. A LARGE UPPER TROUGH WILL THEN SWING DOWN FROM THE GULF OF
ALASKA GOING INTO THE EXTENDED PERIOD WITH COOLER CONDITIONS AND
MORE CHANCES OF PRECIPITATION. 88
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...A RIDGE OF HIGH
PRESSURE SHOULD BRING A WARMER AND MAINLY DRY DAY FOR MONDAY. A
DISTURBANCE WILL APPROACH THE TWO STATE AREA MONDAY NIGHT THAT COULD
SPREAD SOME SHOWERS ALONG THE WA/OR CASCADES. AS A STRONG LOW
PRESSURE SYSTEM DIPS TOWARD THE PACNW TUESDAY...THE SHOWERS SHOULD
MOVE INTO THE REMAINDER OF THE REGION. THE LOW PRESSURE REMAINS
NEARLY STATIONARY AND KEEPS THE CLOUDS AND SHOWERS ALONG WITH THE
COOL TEMPERATURES ACROSS THE TWO STATE AREA THROUGH THURSDAY. THE
LOW IS FORECAST TO DRIFT NORTH AND SOME DRYING IS POSSIBLE FOR
FRIDAY AND SATURDAY ALONG WITH SLIGHTLY WARMER TEMPERATURES.
&&
.AVIATION...LCL MVFR CEILINGS WILL OCCUR ON OCCASION AT ALL TAF
SITES. A DISTURBANCE MOVING ACROSS THE REGION WILL BRING SHOWERS TO
PORTIONS OF THE REGION BEFORE SLOWLY MOVING EAST AND CONDITIONS
SHOULD RETURN TO MAINLY VFR BY 02Z. ANOTHER DISTURBANCE WILL
APPROACH THE TWO STATE AREA TOMORROW MORNING AND LOWER CEILINGS WITH
LCL MVFR CONDITIONS MAINLY NEAR TAF SITE KDLS AND KRDM AND KYKM
AFTER 15Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 66 40 67 / 20 20 20 10
ALW 48 68 45 67 / 20 20 20 10
PSC 48 73 45 72 / 10 20 10 10
YKM 44 68 42 70 / 10 20 10 10
HRI 46 70 45 70 / 10 20 10 10
ELN 45 66 43 66 / 10 20 10 10
RDM 37 61 30 60 / 10 30 20 10
LGD 40 62 40 60 / 40 20 20 20
GCD 41 59 36 61 / 30 30 20 10
DLS 48 65 45 65 / 10 20 20 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SATURDAY : GREEN
SUNDAY : GREEN
MONDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
88/97/97
000
FXUS65 KBOI 172059
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
257 PM MDT FRI MAY 17 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY...HEATING OF THE DAY COMBINED
WITH MOISTURE ASSOCIATED WITH AN UPPER TROUGH WAS RESULTING IN
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. INSTABILITY WAS MARGINAL
TO SUPPORT THUNDERSTORMS...ALTHOUGH ENOUGH TO KEEP ISOLATED COVERAGE
IN THE FORECAST THROUGH THIS EVENING. DRIER STABLE AIR WILL
TEMPORARILY MOVE INTO SE OREGON LATE TONIGHT AND SATURDAY MORNING
WITH A SHORT WAVE UPPER RIDGE. ANOTHER TROUGH WILL THEN MOVE INTO
THE PACNW SATURDAY AFTERNOON...THEN SLOWLY WORK EASTWARD ACROSS THE
AREA THROUGH SUNDAY. THE SECOND TROUGH WILL BRING MORE MOISTURE AND
A CHANCE OF MOUNTAIN/SLIGHT CHANCE OF VALLEY SHOWERS...ALTHOUGH THE
SYSTEM WILL BE WEAKER AND WITH LESS MOISTURE. SNOW LEVELS WILL LOWER
TO AROUND 7500 FEET MSL WITH LIGHT SNOW ACCUMULATIONS POSSIBLE ON
THE PEAKS. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL THROUGH
THE WEEKEND. BREEZY NORTHWEST WINDS ARE EXPECTED SATURDAY AFTERNOON
WITH A LITTLE STRONGER WINDS EXPECTED SUNDAY AFTERNOON...ESPECIALLY
IN THE UPPER TREASURE VALLEY AND WESTERN MAGIC VALLEY.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...A SHORTWAVE RIDGE WILL
BUILD INTO THE AREA FROM THE WEST EARLY MONDAY...ALLOWING SKIES TO
CLEAR AND TEMPS TO RISE TO NEAR NORMAL VALUES MONDAY AFTERNOON. AS A
DEEP LOW PRESSURE SYSTEM SLIDES SOUTHWARD INTO THE PACIFIC NORTHWEST
ON TUESDAY...SOUTHWEST FLOW WILL PICK UP OVER THE INTERMOUNTAIN WEST
WHICH WILL DRIVE THE AFTERNOON HIGH TEMPERATURES TO AROUND 5 DEGREES
ABOVE NORMAL. THE LOW WILL CONTINUE TO MOVE SOUTHWARD...BRINGING A
STRONG SURFACE COLD FRONT THROUGH SE OREGON AND SW IDAHO LATE TUESDAY
NIGHT. EXPECT HIGH TEMPS ON WEDNESDAY TO BE NEARLY 20 DEGREES COOLER
THAN TUESDAY. THE LOW PRESSURE SYSTEM WILL STALL OUT OVER THE PAC NW
THROUGH THE END OF THE WEEK...KEEPING CONDITIONS COOL AND UNSETTLED.
MOST OF THE AVAILABLE MOISTURE LOOKS TO BE ON THE NORTHERN HALF OF
THE LOW CIRCULATION...WITH THE SOUTHERN PORTION OF THE LOW AFFECTING
OUR AREA. THUS THE BEST CHANCE FOR SHOWERS WILL BE ACROSS OUR
NORTHERN AND WESTERN MOUNTAIN ZONES.
&&
.AVIATION...BKN-OVC CLOUD DECK AT GENERALLY 5K-7K FEET MSL WITH
SCATTERED MVFR SHOWERS THROUGH THIS EVENING. ISOLATED THUNDERSTORMS
ACROSS ALL AREAS THIS EVENING. WEST-NORTHWEST SURFACE WINDS AT 10-15
KTS. WEST WINDS ALOFT UP TO 20 KTS AT 10K FEET MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY - MAINLY ACROSS SE OREGON AND HIGHER TERRAIN
OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS CONFINED TO THE
CENTRAL IDAHO MOUNTAINS AND EASTWARD.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...BW
LONG TERM....CB
AVIATION.....CB
000
FXUS66 KPDT 171748 AAA
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1040 AM PDT FRI MAY 17 2013
UPDATED THE AVIATION DISCUSSION
.UPDATE...A WEAK WEATHER DISTURBANCE IS MOVING UP AND ACROSS THE
FORECAST AREA THIS MORNING. CURRENT RADAR IMAGERY IS SHOWING SOME
ASSOCIATED SHOWERS WITH THIS DISTURBANCE STRETCHING IN A LINE FROM
YAKIMA COUNTY SOUTHEAST ACROSS THE SOUTHERN PORTION OF THE LOWER
COLUMBIA BASIN INTO THE SOUTHERN BLUE MOUNTAINS/FOOTHILLS. THIS AREA
OF PRECIPITATION IS MOVING TO THE NORTH AND IT SHOULD BEGIN TO
AFFECT THE NORTHERN BLUE MOUNTAIN FOOTHILLS AND THE NORTHERN AREAS
OF THE LOWER COLUMBIA BASIN...THE SIMCOE HIGHLANDS AND THE NORTHERN
BLUE MOUNTAINS WITHIN THE NEXT COUPLE OF HOURS. PRECIPITATION
AMOUNTS WILL BE VERY LIGHT AND MOST OF IT MAY NOT EVEN REACH THE
GROUND EXCEPT FOR THE HIGHER ELEVATIONS WHERE THERE IS LESS CHANCE
FOR EVAPORATION AS THE PRECIP FALLS. THERE SHOULD BE PARTIAL
CLEARING THIS AFTERNOON. THIS WILL ALLOW SURFACE HEATING TO TAKE
PLACE WHICH WILL HELP TO DESTABILIZE THE ATMOSPHERE. HAVE ISOLATED
THUNDERSTORMS IN FOR THIS AFTERNOON OVER THE EASTERN AND SOUTHEAST
ZONES STRETCHING FROM THE JOHN DAY HIGHLANDS NORTHEAST ACROSS THE
BLUE MOUNTAINS EASTWARD TO THE IDAHO BORDER. ANY THUNDERSTORMS THAT
DEVELOP SHOULD BE WEAK AND NON-SEVERE. HOWEVER THERE COULD BE GUSTY
AND ERRATIC WINDS...BRIEF HEAVY RAIN AND SMALL HAIL WITH ANY STORMS
THAT FORM. 88
.AVIATION...LCL MVFR CEILINGS WILL OCCUR ON OCCASION AT ALL TAF
SITES. A DISTURBANCE MOVING ACROSS THE REGION WILL BRING SHOWERS TO
PORTIONS OF THE REGION BEFORE SLOWLY MOVING EAST AND CONDITIONS
SHOULD RETURN TO MAINLY VFR BY 02Z. ANOTHER DISTURBANCE WILL
APPROACH THE TWO STATE AREA TOMORROW MORNING AND LOWER CEILINGS WITH
LCL MVFR CONDITIONS MAINLY NEAR TAF SITE KDLS AND KRDM AND KYKM
AFTER 15Z.
&&
.PREV DISCUSSION... /ISSUED 421 AM PDT FRI MAY 17 2013/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL LINGER OVER EASTERN WASHINGTON AND OREGON TODAY THROUGH
SATURDAY MORNING. THE TROUGH WILL SHIFT EAST SATURDAY AFTERNOON. THE
TROUGH WILL KEEP CLOUDS AND VARYING CHANCES OF SHOWERS OVER THE AREA
TODAY THROUGH SATURDAY EVENING. DAYTIME HEATING WILL ENHANCE THE
INSTABILITY ASSOCIATED WITH THE TROUGH THIS AFTERNOON...ESPECIALLY
OVER GRANT COUNTY TO THE BLUES AND WALLOWA COUNTY. THIS MAY TRIGGER
A FEW THUNDERSTORMS DURING THE AFTERNOON AND EVENING IN THESE AREAS.
THERE WILL BE A BRIEF BREAK LATE TONIGHT AS THE ATMOSPHERE BRIEFLY
STABILIZES WITH THE LOSS OF DAYTIME HEATING. AS THE TROUGH SHIFTS
EAST SATURDAY EVENING SHOWERS WILL END. SHOWERS WILL LINGER
OVERNIGHT IN WALLOWA COUNTY. WINDS WILL INCREASE SATURDAY AFTERNOON
AND EVENING BEHIND THE TROUGH...PARTICULARLY THROUGH THE COLUMBIA
RIVER GORGE AND KITTITAS VALLEY WHERE GAPS IN THE CASCADES FUNNEL
THE WINDS. COONFIELD
LONG TERM...SUNDAY THROUGH MONDAY NIGHT...A MID/UPPER LEVEL TROUGH
WILL EXIT THE FORECAST AREA SUNDAY FOR A DRYING TREND KICKING IN FOR
MOST OF THE FORECAST AREA. HOWEVER, SOME WRAP AROUND MOISTURE WILL
KEEP A SLIGHT CHANCE OF SHOWERS OVER THE BLUE MOUNTAINS AND FAR
NORTHEAST OREGON THROUGH SUNDAY AFTERNOON. SUNDAY NIGHT A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/137W IN THE SOUTHERN JETSTREAM. MONDAY THESE TWO SYSTEMS
BEGIN MERGING WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD
INTO THE EASTERN FLANK OF THE MID/UPPER LEVEL CIRCULATION ASSOCIATED
WITH THE UPPER LOW MOVING SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
TUESDAY THROUGH THURSDAY...ON TUESDAY THE LARGE UPPER LOW CONTINUES
MOVING SOUTHEAST WITH THE CENTER OF THE LOW ARRIVING ON THE COAST
JUST NORTH OF THE COLUMBIA RIVER BY TUESDAY AFTERNOON. THIS WILL
CAUSE A SOUTHWEST FLOW ALOFT TO BACK TO THE SOUTH OVER THE INTERIOR
PACIFIC NORTHWEST AND TRANSPORT MOISTURE AND INCREASING INSTABILITY
INTO THE REGION. THE APPROACHING COLD UPPER LOW WILL USHER IN A
COOLING TREND, AS THE UPPER LOW CENTER COMES NEARER TO THE FORECAST
AREA. THE UPPER LOW WILL PERSIST OVER THE PACIFIC NORTHWEST THROUGH
THURSDAY. HOWEVER, FROM ONE RUN TO THE NEXT, THE GFS AND ECMWF
SOLUTIONS ARE EXHIBITING SIGNIFICANT DIFFERENCES IN THE PLACEMENT OF
THE CENTER OF THE UPPER LOW, AND A COMPARISON OF THE PLACEMENT OF
THE CENTER OF THE UPPER LOW BETWEEN THE GFS AND ECMWF MODELS FOR A
GIVEN FORECAST BASE TIME LIKEWISE SHOW SIGNIFICANT DIFFERENCES. AS
SUCH UNCERTAINTY IN THE FORECAST IS GREATER THAN NORMAL FOR TUESDAY
THROUGH THURSDAY IN TERMS OF LARGE STANDARD DEVIATIONS IN THE
OVERALL 500MB HEIGHT PATTERN IN BOTH MODELS. HOWEVER, WITH EACH
ADDITIONAL MODEL RUN, THE GFS AND ECMWF MODELS ARE DISPLAYING BETTER
AGREEMENT FOR TUESDAY THROUGH THURSDAY. EXPECT COOL AND UNSETTLED
CONDITIONS WITH PERIODS OF SHOWERS EACH DAY FROM TUESDAY THROUGH
THURSDAY. DAYTIME HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN
NORMAL. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 69 45 68 43 / 20 20 20 20
ALW 70 51 70 48 / 20 20 20 20
PSC 76 51 75 48 / 10 10 10 10
YKM 72 47 70 45 / 20 10 10 10
HRI 73 49 72 48 / 10 10 20 10
ELN 72 48 68 46 / 20 10 20 10
RDM 63 40 63 33 / 20 10 30 20
LGD 63 43 64 43 / 40 40 20 20
GCD 63 44 61 39 / 50 30 20 20
DLS 70 51 67 48 / 20 10 20 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
88/99/99
000
FXUS66 KPQR 171602
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
902 AM PDT FRI MAY 17 2013
.SYNOPSIS...SCATTERED SHOWERS AND SUNBREAKS ARE EXPECTED TODAY AS A
WEAK UPPER LEVEL TROUGH LINGERS OVER THE PACIFIC NORTHWEST. SURFACE
HIGH PRESSURE MAY BRING A BRIEF BREAK IN THE SHOWERS TONIGHT. THE
NEXT PACIFIC SYSTEM WILL MOVE IN SATURDAY...PROBABLY BRINGING A
PERIOD OF STEADY LIGHT RAIN SATURDAY FOLLOWED BY DECREASING SHOWERS
SATURDAY NIGHT AND SUNDAY. DRIER WEATHER IS EXPECTED SUN NIGHT/MON...
BUT IT IS LOOKING MORE LIKELY THAT A COOL AND UNSETTLED PATTERN WILL
SET UP OVER THE PACIFIC NORTHWEST FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SUNDAY...A WEAK UPPER LEVEL TROUGH
EXTENDS FROM VANCOUVER ISLAND SOUTHEAST ACROSS WASHINGTON...OREGON
AND NEVADA THIS MORNING. THE BETTER DEFINED AREA OF LOW PRESSURE
ASSOCIATED WITH THIS SYSTEM APPEARS TO BE NEAR LAS VEGAS...WITH AN
ATTENDANT COLD FRONT PUSHING ACROSS THE US/MEXICO BORDER NEAR SAN
DIEGO AND TIJUANA. SO THE BEST ENERGY WITH THIS SYSTEM IS WELL TO OUR
SOUTH...JUST SOME LINGERING MOISTURE AND WEAK/SHALLOW INSTABILITY FOR
SOME SCATTERED SHOWERS ACROSS OUR FORECAST AREA TODAY. 12Z KSLE
SOUNDING SHOWS A DISTINCT CAP NEAR 700 MB WHICH WILL LIMIT SFC BASED
CONVECTION TO AROUND 10KFT...NOT NEARLY ENOUGH FOR THUNDER. TEMPS
TODAY WILL BE SEASONABLE IN THE MID TO UPPER 60S.
SUBSIDENCE WILL INCREASE THIS EVENING AS SURFACE HIGH PRESSURE BUILDS
INTO OREGON. THIS SHOULD BRING A GRADUAL END TO SHOWER ACTIVITY BUT
IT WILL PROBABLY REMAIN CLOUDY DUE TO THE MOIST LOW LEVEL AIR MASS.
NAM CROSS SECTIONS THROUGH THE WILLAMETTE VALLEY SEEM TO SUPPORT THIS
THINKING. EITHER WAY...IT WILL NOT BE LONG BEFORE HIGHER CLOUDS BEGIN
TO MOVE IN AHEAD OF OUR NEXT SYSTEM NOW SHOWN CROSSING 140W-135W ON
IR IMAGERY.
STILL LOOKS LIKE A DECENT CHANCE FOR RAIN THROUGHOUT THE DISTRICT
SATURDAY AS THAT MODEST FRONTAL SYSTEM MOVES ONSHORE. THERE WILL BE
SOME WEAK ISENTROPIC LIFT AHEAD OF THIS SYSTEM...SO JUST ABOUT
EVERYONE SHOULD GET SOME LIGHT RAIN. ONLY MODEST OROGRAPHIC
ENHANCEMENT WITH 15-25 KT SW 850 MB WINDS...SO EXPECT RAIN TOTALS TO
RANGE FROM 0.10-0.25 INCH IN THE VALLEYS AND 0.50 TO LOCALLY 1 INCH
IN THE HIGHER TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH
A FEW LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER NEAR OR A LITTLE BELOW NORMAL THROUGH THE
WEEKEND. SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES. WEAGLE
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SUNDAY NIGHT
THROUGH THURSDAY...AFTER A BRIEF BREAK OF POTENTIALLY SUNNY AND
SEASONABLE WEATHER MONDAY...IT APPEARS AN EXTENDED COOL AND
UNSETTLED PERIOD IS BECOMING INCREASINGLY LIKELY FOR MIDWEEK. MODELS
ARE SHOWING RELATIVELY GOOD AGREEMENT THAT A COLD AND CLOSED UPPER
LOW WILL DIG DOWN FROM ALASKA...SETTLING SOMEWHERE NEAR THE PAC NW
TUE AND LINGERING THROUGH THURSDAY. COLD AIR ALOFT WILL KEEP THE AIR
MASS UNSTABLE...WITH COOL SHOWERY WEATHER AND POSSIBLY EVEN A
THUNDERSTORM OR TWO DEPENDING ON HOW THINGS EVOLVE.
FAIRLY HIGH DEGREE OF CONFIDENCE OF BELOW NORMAL TEMPS DURING THIS
PERIOD ALONG WITH HIT AND MISS SHOWERS. SNOW LEVELS MAY VERY WELL GET
BELOW THE PASSES...BUT WE WILL PLAY IT CONSERVATIVE FOR NOW WITH SNOW
LEVELS BOTTOMING OUT AROUND 4000-4500 FT MIDWEEK. IF MODELS CONTINUE
TO BRING THE CENTER OF THE COLD POOL OVER THE PAC NW...THESE SNOW
LEVELS WILL NEED TO COME DOWN A BIT AND POSSIBLY AS LOW AS 2000-3000
FEET. WEAGLE
&&
.AVIATION...AN OFFSHORE LOW CONTINUES TO SPREAD SOME SHOWERS OVER
THE S WA CASCADES AND ALONG THE S WA/N OR COAST THIS MORNING. THE
FLOW WILL TURN MORE SOUTHWESTERLY AND WESTERLY THIS AFTERNOON
WITH A FEW SHOWERS SPREADING OFF THE HIGHER TERRAIN OVER THE
VALLEYS. A FEW POCKETS OF MVFR CIGS REMAIN THIS MORNING...BUT
EXPECT WIDESPREAD VFR CONDITIONS TO DEVELOP SHORTLY AND CONTINUE
THROUGH THIS EVENING. THE SHOWER ACTIVITY SHOULD DIMINISH THIS
EVENING AS THE UPPER LEVEL TROUGH AXIS PUSHES EAST OF THE
CASCADES. WITH THE ONSHORE FLOW...EXPECT MVFR CIGS TO SPREAD BACK
INTO THE COAST OVERNIGHT...POSSIBLY PUSHING INLAND AS WELL.
KPDX AND APPROACHES...VFR CIGS TODAY. SOME LIGHT SHOWER ACTIVITY
MAY AFFECT THE TERMINAL AT TIMES DURING THE DAYTIME HOURS. SHOWERS
WILL DIMINISH THIS EVENING. THERE IS A CHANCE OF MVFR CIGS BY
SUNRISE SATURDAY. PYLE
&&
.MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS
THROUGH TONIGHT AS ONE SYSTEM WEAKENS AND MOVES EAST AND BEFORE THE
NEXT SYSTEM ARRIVES. PREFRONTAL SOUTHERLY SMALL CRAFT ADVISORY WINDS
ARE POSSIBLE BY EARLY SATURDAY AND THROUGH MOST OF SATURDAY.
NORTHWEST WINDS WILL THEN PREDOMINATE THE REMAINDER OF THE WEEKEND
AND MUCH OF NEXT WEEK...AND MAY REQUIRE A SMALL CRAFT ADVISORY
AT TIMES NEXT WEEK.
SEAS ARE FORECAST TO REMAIN AROUND 5 OR 6 FT FOR SEVERAL DAYS...
POSSIBLY 7 FT OR SO WITH THE FRONT SATURDAY. WE MAY SEE SEAS
REACH 10 FT NEXT WEEK DUE TO THE BRISK NORTHWEST WINDS. PYLE/PT
&&
.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.
000
FXUS66 KMFR 171559
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
859 AM PDT FRI MAY 17 2013
.DISCUSSION...THE FORECAST WAS UPDATED TO INCREASE THE CLOUD
COVER FORECAST FOR THE REMAINDER OF THIS MORNING. THOUGH IT WILL
BE DECREASING TO PARTLY CLOUDY OVER MOST VALLEYS INTO THE
AFTERNOON. A VERY WEAK SHORTWAVE TROUGH PRESENTLY OFFSHORE WILL
MOVE INLAND THIS AFTERNOON AND EVENING WITH A SLIGHT CHANCE OF
SHOWERS...MAINLY FOR THE HIGHER TERRAIN OF COOS AND DOUGLAS COUNTIES.
THE OTHER UPDATE WAS TO INCREASE WEST TO NORTHWEST WIND SPEEDS
SATURDAY AFTERNOON AND EVENING. IT WILL BE BREEZY EAST OF THE
CASCADES WITH 10 TO 20 MPH WINDS GUSTING TO 30 MPH.
THE INCREASE IN WIND SPEED WILL BE IN RESPONSE TO ANOTHER COLD
FRONT. THIS FRONT WILL MOVE EAST ACROSS OUR AREA SATURDAY WITH THE
HIGHEST PROBABILITY FOR RAIN ALONG THE COAST AND INTO THE UMPQUA
BASIN. THE PROBABILITY OF RAIN FORECAST FOR TOMORROW WILL BE A
FOCUS FOR FURTHER REFINEMENT WITH THE AFTERNOON FORECAST ISSUANCE.
THE WARMING AND DRYING TREND SUNDAY INTO MONDAY STILL LOOKS TO BE
SHORT-LIVED. A COLD CLOSED UPPER LEVEL LOW IS LIKELY TO BE THE
DOMINANT FEATURE TUESDAY INTO FRIDAY WITH PERIODS OF RAIN...MOSTLY
IN THE FORM OF SHOWERS.
&&
.AVIATION...
BASED ON THE 17/12Z TAF CYCLE.
CONSIDERABLE CLOUDINESS EXISTS ACROSS THE REGION THIS MORNING AS
COOL, MOIST ONSHORE FLOW CONTINUES. THERE ARE ALSO A FEW SHOWERS
DRIFTING AROUND BUT THOSE WILL DECREASE THROUGH THE MORNING. DESPITE
BROKEN TO OVERCAST SKIES, MOST TERMINALS REMAIN VFR. THE ONLY
EXCEPTION IS ROSEBURG WHERE SOME IFR STRATUS DEVELOPED OVERNIGHT.
EXPECT ALL THESE CLOUDS TO GRADUALLY BREAK UP TODAY WITH SCATTTERD
SKIES AND VFR CONDITIONS AREA-WIDE THIS AFTERNOON AND EVENING.
WILL LIKELY SEE IFR STRATUS COME BACK TO THE COAST TONIGHT AND
POSSIBLY INTO THE UMPQUA, OTHERWISE, VFR CONTINUES TONIGHT.
-WRIGHT
&&
.PREV DISCUSSION... /ISSUED 311 AM PDT FRI MAY 17 2013/
DISCUSSION...CURRENTLY..THE MID LEVEL TROUGH AXIS IS PASSING OVER
THE AREA...RESULTING IN LIGHT SCATTERED SHOWERS ACROSS MUCH OF THE
CWA. MOST SHOWER ACTIVITY IS LOW ENOUGH TO STAY UNDER THE
RADAR...BUT SURFACE OBS AROUND THE AREA CONFIRM THE PRESENCE OF
LIGHT RAIN. THROUGH THE MORNING...SHOWER ACTIVITY SHOULD DIMINISH
ON THE WEST SIDE...WITH SHOWERS CONTINUING ON THE EAST SIDE
THROUGH THE DAY. THE BREAK WILL BE BRIEF...AS ANOTHER WEAK FRONT
AND ASSOCIATED THROUGH MAKE THEIR WAY ONSHORE SATURDAY MORNING.
THE FOCUS OF THIS SYSTEM WILL BE TO THE NORTH...AND AS SUCH HAVE
KEPT LIKELY POPS NORTH OF THE UMPQUA DIVIDE. HOWEVER...SLIGHT TO
CHANCE POPS REMAIN FOR THE REMAINDER OF THE FORECAST AREA. OF NOTE
SATURDAY...SNOW LEVEL LOOK TO DROP TO NEAR 5000 FEET NEAR AND
NORTH OF CRATER LAKE SATURDAY MORNING...AND THEREFORE PRECIP WOULD
START AS SNOW IN THOSE AREAS...BUT WITH DAYTIME HEATING...THE SNOW
LEVELS WILL RISE...AND THE BULK OF THE PRECIPITATION FALLING ON
SATURDAY WILL BE RAIN. PRECIPITATION SHOULD EXIT THE AREA SATURDAY
NIGHT...ALTHOUGH SOME LAGGING SHOWERS COULD REMAIN OVER THE
UMPQUA BASIN AND NORTHERN CASCADES THROUGH SUNDAY MORNING.
RIDGING WILL THEN DOMINATE THE AREA UNTIL MONDAY NIGHT...AND
DURING THIS TIME...A THERMAL TROUGH IS LIKELY TO PRODUCE THE
NORMAL EFFECTS...WARMING TEMPERATURES...MOSTLY CLEAR SKIES...AND
GUSTY WINDS ACROSS RIDGELINES. THE CHETCO EFFECT WOULD ALSO BE A
LIKELY PLAYER...BUMPING UP TEMPERATURES ALONG THE SOUTHWESTERN
OREGON COAST. HAVE MADE ADJUSTMENTS TO THE TEMPERATURE FORECAST TO
ACCOUNT FOR THIS.
MONDAY EVENING INTO TUESDAY MORNING...MODELS DEPICT A LARGE CLOSED
LOW TO DROP DOWN FROM NEAR THE QUEEN CHARLOTTE ISLANDS INTO THE
PACIFIC NORTHWEST...AND REMAINING OVER THE REGION THROUGHOUT THE
REMAINDER OF THE FORECAST PERIOD. MODELS HAVE BEEN HITTING ON
THIS FEATURE DAY IN AND DAY OUT...AND HAVE BEEN REMARKABLY
CONSISTENT IN STRENGTH AND POSITION...WITH A FEW EXCEPTIONS. DUE
TO THIS...THERE IS HIGH CONFIDENCE IN THE EXISTENCE OF THE
FEATURE...HOWEVER MANY DETAILS REMAIN TO BE IRONED OUT. FOR
INSTANCE...THE EXACT POSITION OF THE LOW AND THE TIMING OF ANY
SHORTWAVES ORBITING IT WILL MAKE A BIG DIFFERENCE IN THE
AMOUNT...LOCATION...AND EVEN TYPE OF PRECIPITATION THAT COULD
OCCUR. WHILE ANOMALOUSLY LOW 500 HEIGHTS ARE LIKELY...MOISTURE
WOULD APPEAR TO BE THE LIMITING FACTOR IN MOST MODEL SOLUTIONS. AS
A RESULT OF THIS UNCERTAINTY IN THE DETAILS...HAVE GONE WITH
MOSTLY CHANCE POPS ACROSS THE ENTIRE CWA FOR THE BULK OF THE TERM.
A POSSIBLE SCENARIO TO WATCH FOR IN THE COMING DAYS WOULD BE THE
POSSIBILITY OF PASS LEVEL SNOW...AND SNOW ACROSS PORTIONS OF THE
EAST SIDE. MODEL SOLUTIONS DEPICT A SIGNIFICANT DROP IN SNOW
LEVELS...AND SHOULD THIS VERIFY...A LATE MAY SNOW EVENT IS NOT OUT
OF THE QUESTION. THIS AN OTHER DETAILS WILL HAVE TO BE ADDRESSED
IN SHIFTS OVER THE NEXT SEVERAL DAYS.
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES WILL BE THE RULE
THROUGH THE WEEK...WITH THE EXCEPTION OF MONDAY...WHEN THE THERMAL
TROUGH AND OFFSHORE FLOW WILL WORK TO BRIEFLY RAISE TEMPERATURES
TO ABOVE NORMAL VALUES.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
DW/BTL
000
FXUS65 KBOI 171543
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
942 AM MDT FRI MAY 17 2013
.DISCUSSION...SHOWERS CONTINUE THIS MORNING AS AN UPPER TROUGH MOVE
THROUGH THE REGION. AIR MASS WILL BE MARGINALLY UNSTABLE TODAY...BUT
ENOUGH TO WARRANT ISOLATED THUNDERSTORMS IN SE OREGON AND SW IDAHO
THIS AFTERNOON AND EVENING. ONLY CHANGE WILL BE TO THUNDERSTORM
COVERAGE...OTHERWISE FORECAST IS ON TRACK.
&&
.AVIATION...BKN-OVC CLOUD DECK AT GENERALLY 5K-6K FEET MSL WITH
SCATTERED MVFR SHOWERS THROUGH THIS EVENING. IFR CONDITIONS IN LOW
STRATUS AT KJER AND KMYL WILL INCREASE TO VFR BY MID-DAY. ISOLATED
THUNDERSTORMS ACROSS ALL AREAS THIS AFTERNOON AND EVENING.
WEST-NORTHWEST SURFACE WINDS AT 10-15 KTS. WEST WINDS ALOFT UP TO 20
KTS AT 10K FEET MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY - MAINLY ACROSS SE OREGON AND HIGHER TERRAIN
OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS CONFINED TO THE
CENTRAL IDAHO MOUNTAINS AND EASTWARD.
&&
.PREV DISCUSSION...
SHORT TERM...UPPER TROUGH AND SHOWERS MOVING ACROSS OUR CWA FROM
WEST TO EAST TODAY. TROUGH WILL EXIT EAST TONIGHT AND SHOWERS WILL
DECREASE...BUT ANOTHER UPPER TROUGH WILL COME IN FROM THE NORTHWEST
SATURDAY. RELATIVELY HIGH POPS TODAY IN MOUNTAIN AREAS...CHANCE
POPS IN THE VALLEYS. TREASURE VALLEY WILL BE PARTIALLY RAIN-SHADOWED
BY THE OWYHEES BUT BUFR SOUNDINGS AT KBOI SHOW LOW LEVEL DRYNESS
ANYWAY. TOTAL QPF WILL BE LIGHT...IN THE MOUNTAINS NO MORE THAN
.25 INCH TOTAL PCPN THROUGH SATURDAY. VALLEYS WILL BE LUCKY TO GET
.10 INCH TOTAL. AIR MASS WILL DESTABILIZE ENOUGH THIS AFTERNOON
FOR A CHANCE OF THUNDERSTORMS ESPECIALLY ON THE IDAHO SIDE. AIR
MASS WILL BE MARGINALLY UNSTABLE AGAIN SATURDAY AFTERNOON FOR A
SLIGHT CHANCE OF THUNDERSTORMS IN SOUTHEASTERN OREGON AND IN WESTERN
IDAHO EXCEPT THE SNAKE BASIN WHICH LOOKS TOO DRY.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...A REINFORCING TROUGH
WILL DIG SOUTHEAST FROM WASHINGTON SATURDAY NIGHT...FOR A
CONTINUATION OF COOL AND SHOWERY CONDITIONS THROUGH THE REMAINDER OF
THE WEEKEND. THIS SYSTEM WILL BE FORCED EASTWARD LATE SUNDAY AS A
STRONG PACIFIC RIDGE MOVES INLAND...INCREASING HEIGHTS AND
THICKNESSES AND ALLOWING TEMPERATURES TO REBOUND BACK TO NEAR NORMAL
ON MONDAY AND SEVERAL DEGREES ABOVE NORMAL ON TUESDAY. WITH A MAJOR
PATTERN CHANGE EXPECTED TUESDAY NIGHT...WARMER CONDITIONS WILL BE
SHORT-LIVED. PATTERN CHANGE WILL BE IN THE FORM OF A STRONG COLD
FRONT...WHICH WILL MOVE SOUTHEAST ACROSS ORE/ID BEGINNING TUESDAY
NIGHT. FRONT WILL THEN USHER IN A DEEP CLOSED LOW OVER THE PACIFIC
NORTHWEST...WHICH WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
THE END OF NEXT WEEK. EXPECT BELOW NORMAL TEMPERATURES AND CHANCES
OF PRECIPITATION WEDNESDAY THROUGH FRIDAY.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...BW
AVIATION.....CB
PREV SHORT TERM...LC
PREV LONG TERM....MT
000
FXUS66 KPDT 171520
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
820 AM PDT FRI MAY 17 2013
.UPDATE...A WEAK WEATHER DISTURBANCE IS MOVING UP AND ACROSS THE
FORECAST AREA THIS MORNING. CURRENT RADAR IMAGERY IS SHOWING SOME
ASSOCIATED SHOWERS WITH THIS DISTURBANCE STRETCHING IN A LINE FROM
YAKIMA COUNTY SOUTHEAST ACROSS THE SOUTHERN PORTION OF THE LOWER
COLUMBIA BASIN INTO THE SOUTHERN BLUE MOUNTAINS/FOOTHILLS. THIS AREA
OF PRECIPITATION IS MOVING TO THE NORTH AND IT SHOULD BEGIN TO
AFFECT THE NORTHERN BLUE MOUNTAIN FOOTHILLS AND THE NORTHERN AREAS
OF THE LOWER COLUMBIA BASIN...THE SIMCOE HIGHLANDS AND THE NORTHERN
BLUE MOUNTAINS WITHIN THE NEXT COUPLE OF HOURS. PRECIPITATION
AMOUNTS WILL BE VERY LIGHT AND MOST OF IT MAY NOT EVEN REACH THE
GROUND EXCEPT FOR THE HIGHER ELEVATIONS WHERE THERE IS LESS CHANCE
FOR EVAPORATION AS THE PRECIP FALLS. THERE SHOULD BE PARTIAL
CLEARING THIS AFTERNOON. THIS WILL ALLOW SURFACE HEATING TO TAKE
PLACE WHICH WILL HELP TO DESTABILIZE THE ATMOSPHERE. HAVE ISOLATED
THUNDERSTORMS IN FOR THIS AFTERNOON OVER THE EASTERN AND SOUTHEAST
ZONES STRETCHING FROM THE JOHN DAY HIGHLANDS NORTHEAST ACROSS THE
BLUE MOUNTAINS EASTWARD TO THE IDAHO BORDER. ANY THUNDERSTORMS THAT
DEVELOP SHOULD BE WEAK AND NON-SEVERE. HOWEVER THERE COULD BE GUSTY
AND ERRATIC WINDS...BRIEF HEAVY RAIN AND SMALL HAIL WITH ANY STORMS
THAT FORM. 88
&&
.PREV DISCUSSION... /ISSUED 421 AM PDT FRI MAY 17 2013/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL LINGER OVER EASTERN WASHINGTON AND OREGON TODAY THROUGH
SATURDAY MORNING. THE TROUGH WILL SHIFT EAST SATURDAY AFTERNOON. THE
TROUGH WILL KEEP CLOUDS AND VARYING CHANCES OF SHOWERS OVER THE AREA
TODAY THROUGH SATURDAY EVENING. DAYTIME HEATING WILL ENHANCE THE
INSTABILITY ASSOCIATED WITH THE TROUGH THIS AFTERNOON...ESPECIALLY
OVER GRANT COUNTY TO THE BLUES AND WALLOWA COUNTY. THIS MAY TRIGGER
A FEW THUNDERSTORMS DURING THE AFTERNOON AND EVENING IN THESE AREAS.
THERE WILL BE A BRIEF BREAK LATE TONIGHT AS THE ATMOSPHERE BRIEFLY
STABILIZES WITH THE LOSS OF DAYTIME HEATING. AS THE TROUGH SHIFTS
EAST SATURDAY EVENING SHOWERS WILL END. SHOWERS WILL LINGER
OVERNIGHT IN WALLOWA COUNTY. WINDS WILL INCREASE SATURDAY AFTERNOON
AND EVENING BEHIND THE TROUGH...PARTICULARLY THROUGH THE COLUMBIA
RIVER GORGE AND KITTITAS VALLEY WHERE GAPS IN THE CASCADES FUNNEL
THE WINDS. COONFIELD
LONG TERM...SUNDAY THROUGH MONDAY NIGHT...A MID/UPPER LEVEL TROUGH
WILL EXIT THE FORECAST AREA SUNDAY FOR A DRYING TREND KICKING IN FOR
MOST OF THE FORECAST AREA. HOWEVER, SOME WRAP AROUND MOISTURE WILL
KEEP A SLIGHT CHANCE OF SHOWERS OVER THE BLUE MOUNTAINS AND FAR
NORTHEAST OREGON THROUGH SUNDAY AFTERNOON. SUNDAY NIGHT A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/137W IN THE SOUTHERN JETSTREAM. MONDAY THESE TWO SYSTEMS
BEGIN MERGING WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD
INTO THE EASTERN FLANK OF THE MID/UPPER LEVEL CIRCULATION ASSOCIATED
WITH THE UPPER LOW MOVING SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
TUESDAY THROUGH THURSDAY...ON TUESDAY THE LARGE UPPER LOW CONTINUES
MOVING SOUTHEAST WITH THE CENTER OF THE LOW ARRIVING ON THE COAST
JUST NORTH OF THE COLUMBIA RIVER BY TUESDAY AFTERNOON. THIS WILL
CAUSE A SOUTHWEST FLOW ALOFT TO BACK TO THE SOUTH OVER THE INTERIOR
PACIFIC NORTHWEST AND TRANSPORT MOISTURE AND INCREASING INSTABILITY
INTO THE REGION. THE APPROACHING COLD UPPER LOW WILL USHER IN A
COOLING TREND, AS THE UPPER LOW CENTER COMES NEARER TO THE FORECAST
AREA. THE UPPER LOW WILL PERSIST OVER THE PACIFIC NORTHWEST THROUGH
THURSDAY. HOWEVER, FROM ONE RUN TO THE NEXT, THE GFS AND ECMWF
SOLUTIONS ARE EXHIBITING SIGNIFICANT DIFFERENCES IN THE PLACEMENT OF
THE CENTER OF THE UPPER LOW, AND A COMPARISON OF THE PLACEMENT OF
THE CENTER OF THE UPPER LOW BETWEEN THE GFS AND ECMWF MODELS FOR A
GIVEN FORECAST BASE TIME LIKEWISE SHOW SIGNIFICANT DIFFERENCES. AS
SUCH UNCERTAINTY IN THE FORECAST IS GREATER THAN NORMAL FOR TUESDAY
THROUGH THURSDAY IN TERMS OF LARGE STANDARD DEVIATIONS IN THE
OVERALL 500MB HEIGHT PATTERN IN BOTH MODELS. HOWEVER, WITH EACH
ADDITIONAL MODEL RUN, THE GFS AND ECMWF MODELS ARE DISPLAYING BETTER
AGREEMENT FOR TUESDAY THROUGH THURSDAY. EXPECT COOL AND UNSETTLED
CONDITIONS WITH PERIODS OF SHOWERS EACH DAY FROM TUESDAY THROUGH
THURSDAY. DAYTIME HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN
NORMAL. POLAN
AVIATION...12Z TAFS...VFR CONDITIONS WILL OCCUR OVER THE NEXT 24
HOURS, EXCEPT AT KBDN WHERE MVFR CIGS ARE LIKELY THIS MORNING.
HOWEVER, SOME TAF SITES MAY EXPERIENCE BRIEF MVFR CONDITIONS DUE TO
LOWERED CIGS FROM SHOWERS. AN APPROACHING MID/UPPER LEVEL TROUGH
JUST WEST OF THE CASCADES AT 4 AM THIS MORNING IS STEERING SHOWERS
ALONG A TRACK DUE NORTHWARD FROM THE EASTERN COLUMBIA RIVER GORGE
SOUTH ACROSS NORTH CENTRAL OREGON AND TO THE SOUTHEAST OVER THE JOHN
DAY RIVER VALLEY. SHOWERS WILL INCREASE IN AREAL COVERAGE AS THE
TROUGH OVERSPREADS CENTRAL AND NE OREGON LATE THIS MORNING THROUGH
THIS EVENING. SHOWERS WILL THEN TAPER OFF AFTER 03Z/18TH. WINDS WILL
BE BREEZY AFTER 21Z AT JUST ABOUT ALL TAF SITES OTHER THAN KPSC AND
KYKM. EXPECT WINDS 5 TO 15 KTS WITH GUSTS OF 20 TO 25 KTS. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 69 45 68 43 / 20 20 20 20
ALW 70 51 70 48 / 20 20 20 20
PSC 76 51 75 48 / 10 10 10 10
YKM 72 47 70 45 / 20 10 10 10
HRI 73 49 72 48 / 10 10 20 10
ELN 72 48 68 46 / 20 10 20 10
RDM 63 40 63 33 / 20 10 30 20
LGD 63 43 64 43 / 40 40 20 20
GCD 63 44 61 39 / 50 30 20 20
DLS 70 51 67 48 / 20 10 20 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
88/99/99
000
FXUS66 KPDT 171122 AAA
AFDPDT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
421 AM PDT FRI MAY 17 2013
UPDATED AVIATION AND LONG TERM DISCUSSIONS
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL LINGER OVER EASTERN WASHINGTON AND OREGON TODAY THROUGH
SATURDAY MORNING. THE TROUGH WILL SHIFT EAST SATURDAY AFTERNOON. THE
TROUGH WILL KEEP CLOUDS AND VARYING CHANCES OF SHOWERS OVER THE AREA
TODAY THROUGH SATURDAY EVENING. DAYTIME HEATING WILL ENHANCE THE
INSTABILITY ASSOCIATED WITH THE TROUGH THIS AFTERNOON...ESPECIALLY
OVER GRANT COUNTY TO THE BLUES AND WALLOWA COUNTY. THIS MAY TRIGGER
A FEW THUNDERSTORMS DURING THE AFTERNOON AND EVENING IN THESE AREAS.
THERE WILL BE A BRIEF BREAK LATE TONIGHT AS THE ATMOSPHERE BRIEFLY
STABILIZES WITH THE LOSS OF DAYTIME HEATING. AS THE TROUGH SHIFTS
EAST SATURDAY EVENING SHOWERS WILL END. SHOWERS WILL LINGER
OVERNIGHT IN WALLOWA COUNTY. WINDS WILL INCREASE SATURDAY AFTERNOON
AND EVENING BEHIND THE TROUGH...PARTICULARLY THROUGH THE COLUMBIA
RIVER GORGE AND KITTITAS VALLEY WHERE GAPS IN THE CASCADES FUNNEL
THE WINDS. COONFIELD
.LONG TERM...SUNDAY THROUGH MONDAY NIGHT...A MID/UPPER LEVEL TROUGH
WILL EXIT THE FORECAST AREA SUNDAY FOR A DRYING TREND KICKING IN FOR
MOST OF THE FORECAST AREA. HOWEVER, SOME WRAP AROUND MOISTURE WILL
KEEP A SLIGHT CHANCE OF SHOWERS OVER THE BLUE MOUNTAINS AND FAR
NORTHEAST OREGON THROUGH SUNDAY AFTERNOON. SUNDAY NIGHT A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/137W IN THE SOUTHERN JETSTREAM. MONDAY THESE TWO SYSTEMS
BEGIN MERGING WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD
INTO THE EASTERN FLANK OF THE MID/UPPER LEVEL CIRCULATION ASSOCIATED
WITH THE UPPER LOW MOVING SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
TUESDAY THROUGH THURSDAY...ON TUESDAY THE LARGE UPPER LOW CONTINUES
MOVING SOUTHEAST WITH THE CENTER OF THE LOW ARRIVING ON THE COAST
JUST NORTH OF THE COLUMBIA RIVER BY TUESDAY AFTERNOON. THIS WILL
CAUSE A SOUTHWEST FLOW ALOFT TO BACK TO THE SOUTH OVER THE INTERIOR
PACIFIC NORTHWEST AND TRANSPORT MOISTURE AND INCREASING INSTABILITY
INTO THE REGION. THE APPROACHING COLD UPPER LOW WILL USHER IN A
COOLING TREND, AS THE UPPER LOW CENTER COMES NEARER TO THE FORECAST
AREA. THE UPPER LOW WILL PERSIST OVER THE PACIFIC NORTHWEST THROUGH
THURSDAY. HOWEVER, FROM ONE RUN TO THE NEXT, THE GFS AND ECMWF
SOLUTIONS ARE EXHIBITING SIGNIFICANT DIFFERENCES IN THE PLACEMENT OF
THE CENTER OF THE UPPER LOW, AND A COMPARISON OF THE PLACEMENT OF
THE CENTER OF THE UPPER LOW BETWEEN THE GFS AND ECMWF MODELS FOR A
GIVEN FORECAST BASE TIME LIKEWISE SHOW SIGNIFICANT DIFFERENCES. AS
SUCH UNCERTAINTY IN THE FORECAST IS GREATER THAN NORMAL FOR TUESDAY
THROUGH THURSDAY IN TERMS OF LARGE STANDARD DEVIATIONS IN THE
OVERALL 500MB HEIGHT PATTERN IN BOTH MODELS. HOWEVER, WITH EACH
ADDITIONAL MODEL RUN, THE GFS AND ECMWF MODELS ARE DISPLAYING BETTER
AGREEMENT FOR TUESDAY THROUGH THURSDAY. EXPECT COOL AND UNSETTLED
CONDITIONS WITH PERIODS OF SHOWERS EACH DAY FROM TUESDAY THROUGH
THURSDAY. DAYTIME HIGH TEMPERATURES WILL BE SLIGHTLY COOLER THAN
NORMAL. POLAN
&&
.AVIATION...12Z TAFS...VFR CONDITIONS WILL OCCUR OVER THE NEXT 24
HOURS, EXCEPT AT KBDN WHERE MVFR CIGS ARE LIKELY THIS MORNING.
HOWEVER, SOME TAF SITES MAY EXPERIENCE BRIEF MVFR CONDITIONS DUE TO
LOWERED CIGS FROM SHOWERS. AN APPROACHING MID/UPPER LEVEL TROUGH
JUST WEST OF THE CASCADES AT 4 AM THIS MORNING IS STEERING SHOWERS
ALONG A TRACK DUE NORTHWARD FROM THE EASTERN COLUMBIA RIVER GORGE
SOUTH ACROSS NORTH CENTRAL OREGON AND TO THE SOUTHEAST OVER THE JOHN
DAY RIVER VALLEY. SHOWERS WILL INCREASE IN AREAL COVERAGE AS THE
TROUGH OVERSPREADS CENTRAL AND NE OREGON LATE THIS MORNING THROUGH
THIS EVENING. SHOWERS WILL THEN TAPER OFF AFTER 03Z/18TH. WINDS WILL
BE BREEZY AFTER 21Z AT JUST ABOUT ALL TAF SITES OTHER THAN KPSC AND
KYKM. EXPECT WINDS 5 TO 15 KTS WITH GUSTS OF 20 TO 25 KTS. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 69 45 68 43 / 20 20 20 20
ALW 70 51 70 48 / 20 20 20 20
PSC 76 51 75 48 / 10 10 10 10
YKM 72 47 70 45 / 20 10 10 10
HRI 73 49 72 48 / 10 10 20 10
ELN 72 48 68 46 / 20 10 20 10
RDM 63 40 63 33 / 20 10 30 20
LGD 63 43 64 43 / 40 40 20 20
GCD 63 44 61 39 / 50 30 20 20
DLS 70 51 67 48 / 20 10 20 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
76/99/99
000
FXUS66 KMFR 171011
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
311 AM PDT FRI MAY 17 2013
.DISCUSSION...CURRENTLY..THE MID LEVEL TROUGH AXIS IS PASSING OVER
THE AREA...RESULTING IN LIGHT SCATTERED SHOWERS ACROSS MUCH OF THE
CWA. MOST SHOWER ACTIVITY IS LOW ENOUGH TO STAY UNDER THE
RADAR...BUT SURFACE OBS AROUND THE AREA CONFIRM THE PRESENCE OF
LIGHT RAIN. THROUGH THE MORNING...SHOWER ACTIVITY SHOULD DIMINISH
ON THE WEST SIDE...WITH SHOWERS CONTINUING ON THE EAST SIDE
THROUGH THE DAY. THE BREAK WILL BE BRIEF...AS ANOTHER WEAK FRONT
AND ASSOCIATED THROUGH MAKE THEIR WAY ONSHORE SATURDAY MORNING.
THE FOCUS OF THIS SYSTEM WILL BE TO THE NORTH...AND AS SUCH HAVE
KEPT LIKELY POPS NORTH OF THE UMPQUA DIVIDE. HOWEVER...SLIGHT TO
CHANCE POPS REMAIN FOR THE REMAINDER OF THE FORECAST AREA. OF NOTE
SATURDAY...SNOW LEVEL LOOK TO DROP TO NEAR 5000 FEET NEAR AND
NORTH OF CRATER LAKE SATURDAY MORNING...AND THEREFORE PRECIP WOULD
START AS SNOW IN THOSE AREAS...BUT WITH DAYTIME HEATING...THE SNOW
LEVELS WILL RISE...AND THE BULK OF THE PRECIPITATION FALLING ON
SATURDAY WILL BE RAIN. PRECIPITATION SHOULD EXIT THE AREA SATURDAY
NIGHT...ALTHOUGH SOME LAGGING SHOWERS COULD REMAIN OVER THE
UMPQUA BASIN AND NORTHERN CASCADES THROUGH SUNDAY MORNING.
RIDGING WILL THEN DOMINATE THE AREA UNTIL MONDAY NIGHT...AND
DURING THIS TIME...A THERMAL TROUGH IS LIKELY TO PRODUCE THE
NORMAL EFFECTS...WARMING TEMPERATURES...MOSTLY CLEAR SKIES...AND
GUSTY WINDS ACROSS RIDGELINES. THE CHETCO EFFECT WOULD ALSO BE A
LIKELY PLAYER...BUMPING UP TEMPERATURES ALONG THE SOUTHWESTERN
OREGON COAST. HAVE MADE ADJUSTMENTS TO THE TEMPERATURE FORECAST TO
ACCOUNT FOR THIS.
MONDAY EVENING INTO TUESDAY MORNING...MODELS DEPICT A LARGE CLOSED
LOW TO DROP DOWN FROM NEAR THE QUEEN CHARLOTTE ISLANDS INTO THE
PACIFIC NORTHWEST...AND REMAINING OVER THE REGION THROUGHOUT THE
REMAINDER OF THE FORECAST PERIOD. MODELS HAVE BEEN HITTING ON
THIS FEATURE DAY IN AND DAY OUT...AND HAVE BEEN REMARKABLY
CONSISTENT IN STRENGTH AND POSITION...WITH A FEW EXCEPTIONS. DUE
TO THIS...THERE IS HIGH CONFIDENCE IN THE EXISTENCE OF THE
FEATURE...HOWEVER MANY DETAILS REMAIN TO BE IRONED OUT. FOR
INSTANCE...THE EXACT POSITION OF THE LOW AND THE TIMING OF ANY
SHORTWAVES ORBITING IT WILL MAKE A BIG DIFFERENCE IN THE
AMOUNT...LOCATION...AND EVEN TYPE OF PRECIPITATION THAT COULD
OCCUR. WHILE ANOMALOUSLY LOW 500 HEIGHTS ARE LIKELY...MOISTURE
WOULD APPEAR TO BE THE LIMITING FACTOR IN MOST MODEL SOLUTIONS. AS
A RESULT OF THIS UNCERTAINTY IN THE DETAILS...HAVE GONE WITH
MOSTLY CHANCE POPS ACROSS THE ENTIRE CWA FOR THE BULK OF THE TERM.
A POSSIBLE SCENARIO TO WATCH FOR IN THE COMING DAYS WOULD BE THE
POSSIBILITY OF PASS LEVEL SNOW...AND SNOW ACROSS PORTIONS OF THE
EAST SIDE. MODEL SOLUTIONS DEPICT A SIGNIFICANT DROP IN SNOW
LEVELS...AND SHOULD THIS VERIFY...A LATE MAY SNOW EVENT IS NOT OUT
OF THE QUESTION. THIS AN OTHER DETAILS WILL HAVE TO BE ADDRESSED
IN SHIFTS OVER THE NEXT SEVERAL DAYS.
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES WILL BE THE RULE
THROUGH THE WEEK...WITH THE EXCEPTION OF MONDAY...WHEN THE THERMAL
TROUGH AND OFFSHORE FLOW WILL WORK TO BRIEFLY RAISE TEMPERATURES
TO ABOVE NORMAL VALUES.
&&
.AVIATION...BASED ON THE 17/06Z TAF CYCLE.
ISOLATED TO SCATTERED SHOWERS WILL CONTINUE THIS MORNING OVER THE
AREA WITH ACTIVITY DECREASING AND SHIFTING EAST DURING THE AFTERNOON
AND EVENING. AS OF 10 UTC THIS MORNING...AREA TERMINALS HAVE
MANAGED TO STAY VFR...BUT SOME ONLY BARELY SO. WEST OF THE
CASCADES...AREAS OF MVFR CIGS COULD STILL DEVELOP EARLY THIS
MORNING...BUT ANY LOCATIONS MVFR OR BELOW SHOULD RETURN TO VFR
AROUND 16-18Z. EAST OF THE CASCADES...VFR CONDITIONS WITH ISOLATED
MVFR CIGS ARE EXPECTED THIS MORNING...MAINLY IN THE KLAMATH BASIN.
AFTER 18Z EXPECT VFR CIGS SHOULD PREVAIL ACROSS THE AREA AND
REMAIN IN CONTROL THROUGH THE EVENING. AREAS OF MOUNTAIN
OBSCURATIONS ARE EXPECTED THROUGH THE MORNING.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
BPN/CMC
000
FXUS66 KPDT 171005
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
304 AM PDT FRI MAY 17 2013
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...A BROAD UPPER LEVEL
TROUGH WILL LINGER OVER EASTERN WASHINGTON AND OREGON TODAY THROUGH
SATURDAY MORNING. THE TROUGH WILL SHIFT EAST SATURDAY AFTERNOON. THE
TROUGH WILL KEEP CLOUDS AND VARYING CHANCES OF SHOWERS OVER THE AREA
TODAY THROUGH SATURDAY EVENING. DAYTIME HEATING WILL ENHANCE THE
INSTABILITY ASSOCIATED WITH THE TROUGH THIS AFTERNOON...ESPECIALLY
OVER GRANT COUNTY TO THE BLUES AND WALLOWA COUNTY. THIS MAY TRIGGER
A FEW THUNDERSTORMS DURING THE AFTERNOON AND EVENING IN THESE AREAS.
THERE WILL BE A BRIEF BREAK LATE TONIGHT AS THE ATMOSPHERE BRIEFLY
STABILIZES WITH THE LOSS OF DAYTIME HEATING. AS THE TROUGH SHIFTS
EAST SATURDAY EVENING SHOWERS WILL END. SHOWERS WILL LINGER
OVERNIGHT IN WALLOWA COUNTY. WINDS WILL INCREASE SATURDAY AFTERNOON
AND EVENING BEHIND THE TROUGH...PARTICULARLY THROUGH THE COLUMBIA
RIVER GORGE AND KITTITAS VALLEY WHERE GAPS IN THE CASCADES FUNNEL
THE WINDS. COONFIELD
.LONG TERM...SUNDAY THROUGH MONDAY NIGHT...A MID/UPPER LEVEL TROUGH
WILL EXIT THE FORECAST AREA SUNDAY FOR A DRYING TREND KICKING IN FOR
MOST OF THE FORECAST AREA. HOWEVER, SOME WRAP AROUND MOISTURE WILL
KEEP A SLIGHT CHANCE OF SHOWERS OVER THE BLUE MOUNTAINS AND FAR
NORTHEAST OREGON THROUGH SUNDAY AFTERNOON. SUNDAY NIGHT A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM MOVES SOUTHEAST ALONG THE SE ALASKAN
ARCHIPELAGO AND COMES INTO PHASE WITH A FRONTAL ZONE MOVING EAST
NEAR 45N/137W IN THE SOUTHERN JETSTREAM. MONDAY THESE TWO SYSTEMS
BEGIN MERGING WITH THE SOUTHERN SYSTEM PULLING MOISTURE NORTHWARD
INTO THE EASTERN FLANK OF THE MID/UPPER LEVEL CIRCULATION ASSOCIATED
WITH THE UPPER LOW MOVING SOUTHEAST NEAR QUEEN CHARLOTTE ISLAND.
.TUESDAY THROUGH THURSDAY...ON TUESDAY THE UPPER LOW CONTINUES
MOVING SOUTHEAST WITH THE LOW ARRIVING ON THE COAST BY TUESDAY
AFTERNOON. THIS WILL CAUSE A SOUTHWEST FLOW TO BACK TO THE SOUTH
OVER THE INTERIOR PACIFIC NORTHWEST AND TRANSPORT MOISTURE AND
INCREASING INSTABILITY INTO THE REGION. THE APPROACHING COLD UPPER
LOW MEANS A COOLING TREND WILL TAKE PLACE WITH FALLING HEIGHTS AND
THICKNESSES, AS THE UPPER LOW CENTER COMES MUCH CLOSER TO THE AREA.
THIS PATTERN OF UPPER LOWS WILL PERSIST THROUGHOUT THE REMAINDER OF
THE EXTENDED FORECAST PERIOD... THOUGH WITH VERY SIGNIFICANT
DIFFERENCES IN THE PLACEMENT OF THE UPPER LOWS BETWEEN THESE TWO
MODELS. AS SUCH DID NOT MAKE TOO MANY CHANGES IN THE EXTENDED
FORECAST PERIOD DUE TO THE UNCERTAINTY. HOWEVER THERE IS BETTER
AGREEMENT BETWEEN THE TWO MODELS BY THURSDAY AND THEN THE MODELS
DIVERGE AGAIN FURTHER OUT IN THE EXTENDED FORECAST PERIOD WITH THE
ECMWF BEING MUCH MORE ORGANIZED AND DEEPER THAN THE GFS AND AM
LEANING TOWARD THAT SCENARIO. THE RESULT WILL BE COOL CONDITIONS
WITH PERIODIC SHOWERS. EVEN THOUGH TEMPERATURES WILL BE ON THE COOL
SIDE THEY WILL NOT BE MUCH COOLER THAN NORMAL AND IN FACT THEY WILL
BE CLOSE TO NORMAL FOR THIS TIME OF YEAR. POLAN
&&
.PREVIOUS AVIATION DISCUSSION...06Z TAFS...VFR CONDITIONS ARE
EXPECTED TO PREVAIL OVER THE NEXT 24 HOURS. HOWEVER...SOME TAF SITES
MAY EXPERIENCE BRIEF MVFR CONDITIONS DUE TO LOWERED CIGS FROM
SHOWERS. SHOWERS WILL TAPER OFF OVERNIGHT TONIGHT AND PICK BACK UP
TOMORROW LATE MORNING TO EARLY AFTERNOON. WINDS WILL BE BREEZY AFTER
21Z AT JUST ABOUT ALL TAF SITES OTHER THAN KPSC AND KYKM. EXPECT
WINDS 5 TO 15KTS WITH 20 TO 25KTS AT TIMES. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 69 45 68 43 / 20 20 20 20
ALW 70 51 70 48 / 20 20 20 20
PSC 76 51 75 48 / 10 10 10 10
YKM 72 47 70 45 / 20 10 10 10
HRI 73 49 72 48 / 10 10 20 10
ELN 72 48 68 46 / 20 10 20 10
RDM 63 40 63 33 / 20 10 30 20
LGD 63 43 64 43 / 40 40 20 20
GCD 63 44 61 39 / 50 30 20 20
DLS 70 51 67 48 / 20 10 20 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
TODAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
76/99/99
000
FXUS66 KPQR 170946
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
245 AM PDT FRI MAY 17 2013
.SYNOPSIS...A FEW SHOWERS WILL CONTINUE TODAY ESPECIALLY IN THE
CASCADES AS A WEAK SYSTEM SLIDES TO THE EAST. TRANSITORY HIGH
PRESSURE MAY BRING A BRIEF BREAK IN THE SHOWERS TONIGHT BEFORE THE
NEXT SYSTEM BRINGS ANOTHER DECENT CHANCE FOR RAIN SATURDAY AND
LINGERING SHOWERS SUNDAY. DRIER WEATHER IS EXPECTED SUN NIGHT/MON...
BUT IT IS LOOKING MORE LIKELY THAT A COOL AND UNSETTLED PATTERN WILL
SET UP OVER THE PACIFIC NORTHWEST FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...SHOWERS WILL CONTINUE TODAY ESPECIALLY ACROSS THE
CASCADES AS A WEAK SYSTEM SLIDES TO THE EAST. MODEL SOUNDINGS SHOW
SHALLOW INSTABILITY UP TO 600-700 MB. THIS SHOULD GREATLY LIMIT
SHOWER POTENTIAL TODAY DESPITE A LITTLE MORE SUNSHINE...BUT THERE
WILL STILL BE ENOUGH INSTABILITY FOR SCATTERED SHOWERS THROUGHOUT
THE DAY. THESE WILL DISSIPATE THIS EVENING AS HIGH PRESSURE BRIEFLY
BUILDS OVERHEAD. HOWEVER...THE NEXT SYSTEM NOW NEAR 150W WILL LIKELY
SPREAD RAIN BACK ACROSS THE DISTRICT SATURDAY. QPF SHOULD BE MODEST
WITH AROUND 0.25 INCH IN THE VALLEYS AND UP TO 1 INCH IN THE HIGHER
TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH A FEW
LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER A LITTLE BELOW NORMAL THROUGH THE WEEKEND.
SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SUNDAY NIGHT
THROUGH THURSDAY...AFTER A BRIEF BREAK OF POTENTIALLY SUNNY AND
SEASONABLE WEATHER MONDAY...IT APPEARS AN EXTENDED COOL AND
UNSETTLED PERIOD IS BECOMING INCREASINGLY LIKELY FOR MIDWEEK. MODELS
ARE SHOWING RELATIVELY GOOD AGREEMENT THAT A COLD AND CLOSED UPPER
LOW WILL DIG DOWN FROM ALASKA...SETTLING SOMEWHERE NEAR THE PAC NW
TUE AND LINGERING THROUGH THURSDAY. COLD AIR ALOFT WILL KEEP THE AIR
MASS UNSTABLE...WITH COOL SHOWERY WEATHER AND POSSIBLY EVEN A
THUNDERSTORM OR TWO DEPENDING ON HOW THINGS EVOLVE.
FAIRLY HIGH DEGREE OF CONFIDENCE OF BELOW NORMAL TEMPS DURING THIS
PERIOD ALONG WITH HIT AND MISS SHOWERS. SNOW LEVELS MAY VERY WELL GET
BELOW THE PASSES...BUT WE WILL PLAY IT CONSERVATIVE FOR NOW WITH SNOW
LEVELS BOTTOMING OUT AROUND 4000-4500 FT MIDWEEK. IF MODELS CONTINUE
TO BRING THE CENTER OF THE COLD POOL OVER THE PAC NW...THESE SNOW
LEVELS WILL NEED TO COME DOWN A BIT AND POSSIBLY AS LOW AS 2000-3000
FEET. WEAGLE
&&
.AVIATION...CONSIDERABLE CLOUDS WILL CONTINUE OVER SOUTHWEST
WASHINGTON AND NORTHWEST OREGON TODAY AS A WEAK LOW CONTINUES OFF
THE COAST AND SLOWLY FILLS. THE SOUTHEAST FLOW AROUND THIS LOW WAS
SPREADING SHOWERS FROM CENTRAL OREGON ACROSS THE NORTH OREGON
CASCADES INTO SOUTHWEST WASHINGTON...AND WILL CONTINUE UNTIL AFTER
SUNRISE UNTIL THE MAIN UPPER TROUGH MOVES FARTHER EAST. THE FLOW
WILL TURN MORE SOUTHWESTERLY AND WESTERLY THIS AFTERNOON WITH A
FEW SHOWERS SPREADING OFF THE HIGHER TERRAIN OVER THE VALLEYS.
LOOK FOR VFR CIGS TODAY WITH SOME MVFR CIGS MIXED IN THIS MORNING.
EXPECT MOSTLY VFR CIGS TONIGHT WITH DECREASING SHOWERS BUT CANNOT
RULE OUT SOME PATCHES OF MVFR CIGS BY SUNRISE SATURDAY.
KPDX AND APPROACHES...VFR CIGS TODAY WITH POSSIBLE MVFR CIGS THIS
MORNING. SOME SHOWERS SPREADING IN FROM THE SOUTHEAST MAY AFFECT
THE AIRPORT AT TIMES THIS MORNING...AND ESPECIALLY THE EASTERN
APPROACHES. THE FLOW WILL TURN MORE WESTERLY THIS AFTERNOON AND
COULD STILL SEE A SHOWER OR TWO DRIFT OFF THE COAST RANGE AND
AFFECT THE AIRPORT THIS AFTERNOON AND EVENING. THERE IS A CHANCE
OF MVFR CIGS BY SUNRISE SATURDAY. PT
&&
.MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS
TODAY AND MOST OF TONIGHT AS ONE SYSTEM WEAKENS AND MOVES EAST AND
BEFORE THE NEXT SYSTEM ARRIVES. PREFRONTAL SOUTHERLY SMALL CRAFT
ADVISORY WINDS ARE POSSIBLE BY EARLY SATURDAY AND THROUGH MOST OF
SATURDAY. NORTHWEST WINDS WILL THEN PREDOMINATE THE REMAINDER OF
THE WEEKEND AND MUCH OF NEXT WEEK...AND MAY REQUIRE A SMALL CRAFT
ADVISORY AGAIN ESPECIALLY NEXT WEEK.
SEAS ARE FORECAST TO REMAIN AROUND 5 OR 6 FT FOR SEVERAL DAYS...
POSSIBLY 7 FT OR SO WITH THE FRONT SATURDAY. WE MAY SEE SEAS
REACH 10 FT NEXT WEEK DUE TO THE BRISK NORTHWEST WINDS. PT
&&
.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.
000
FXUS65 KBOI 170939
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
338 AM MDT FRI MAY 17 2013
.SHORT TERM...UPPER TROUGH AND SHOWERS MOVING ACROSS OUR CWA FROM
WEST TO EAST TODAY. TROUGH WILL EXIT EAST TONIGHT AND SHOWERS WILL
DECREASE...BUT ANOTHER UPEPR TROUGH WILL COME IN FROM THE NORTHWEST
SATURDAY. RELATIVELY HIGH POPS TODAY IN MOUNTAIN AREAS...CHANCE
POPS IN THE VALLEYS. TREASURE VALLEY WILL BE PARTIALLY RAIN-SHADOWED
BY THE OWYHEES BUT BUFR SOUNDINGS AT KBOI SHOW LOW LEVEL DRYNESS
ANYWAY. TOTAL QPF WILL BE LIGHT...IN THE MOUNTAINS NO MORE THAN
.25 INCH TOTAL PCPN THROUGH SATURDAY. VALLEYS WILL BE LUCKY TO GET
.10 INCH TOTAL. AIR MASS WILL DESTABILIZE ENOUGH THIS AFTERNOON
FOR A CHANCE OF THUNDERSTORMS ESPECIALLY ON THE IDAHO SIDE. AIR
MASS WILL BE MARGINALLY UNSTABLE AGAIN SATURDAY AFTERNOON FOR A
SLIGHT CHANCE OF THUNDERSTORMS IN SOUTHEASTERN OREGON AND IN WESTERN
IDAHO EXCEPT THE SNAKE BASIN WHICH LOOKS TOO DRY.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...A REINFORCING TROUGH
WILL DIG SOUTHEAST FROM WASHINGTON SATURDAY NIGHT...FOR A
CONTINUATION OF COOL AND SHOWERY CONDITIONS THROUGH THE REMAINDER OF
THE WEEKEND. THIS SYSTEM WILL BE FORCED EASTWARD LATE SUNDAY AS A
STRONG PACIFIC RIDGE MOVES INLAND...INCREASING HEIGHTS AND
THICKNESSES AND ALLOWING TEMPERATURES TO REBOUND BACK TO NEAR NORMAL
ON MONDAY AND SEVERAL DEGREES ABOVE NORMAL ON TUESDAY. WITH A MAJOR
PATTERN CHANGE EXPECTED TUESDAY NIGHT...WARMER CONDITIONS WILL BE
SHORT-LIVED. PATTERN CHANGE WILL BE IN THE FORM OF A STRONG COLD
FRONT...WHICH WILL MOVE SOUTHEAST ACROSS ORE/ID BEGINNING TUESDAY
NIGHT. FRONT WILL THEN USHER IN A DEEP CLOSED LOW OVER THE PACIFIC
NORTHWEST...WHICH WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
THE END OF NEXT WEEK. EXPECT BELOW NORMAL TEMPERATURES AND CHANCES
OF PRECIPITATION WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...BKN-OVC CLOUD DECK /7K-9K FT MSL/ AND NUMEROUS MVFR RAIN
SHOWERS /ALL AREAS/ THROUGH THE AFTERNOON. MTNS WILL BE OBSCURED.
EMBEDDED THUNDERSTORM DEVELOPMENT POSSIBLE AFTER 21Z. LIGHT DIURNAL
WINDS THROUGH 17Z...THEN LIGHT W/NW SURFACE WINDS AFTER 17Z.
WESTERLY WINDS ALOFT WILL AVERAGE 10 AT 10K FT MSL.
WEEKEND OUTLOOK...SCATTERED MVFR SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY - MAINLY ACROSS SE OREGON AND HIGHER TERRAIN
OF SW IDAHO. SUNDAY...PREDOMINANTLY VFR WITH SHOWERS CONFINED TO THE
CENTRAL IDAHO MOUNTAINS AND EASTWARD..
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...LC
LONG TERM....MT
AVIATION.....MT
000
FXUS66 KMFR 170410
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
910 PM PDT THU MAY 16 2013
.SHORT TERM...AN UPPER TROUGH MOVING ACROSS THE REGION IS
BRINGING CONTINUED AREAS OF LIGHT SHOWERS TONIGHT. EXPECT MUCH OF
THE SHOWER ACTIVITY TO BE ISOLATED TO SCATTERED IN NATURE. SO HAVE
ADJUSTED POPS AND WEATHER DOWN THIS EVENING INTO FRIDAY MORNING.
IN ADDITION TO SHOWERS TONIGHT...MODELS ARE SHOWING LOW CLOUDS
DEVELOPING FOR MANY AREAS TONIGHT INTO FRIDAY MORNING...ESPECIALLY
WEST OF THE CASCADES. THE TROUGH SHIFTS EAST ON FRIDAY AND SHOWERS
ARE EXPECTED TO BE ISOLATED FOR MUCH THE WEST SIDE WITH LINGERING
SCATTERED SHOWERS POSSIBLE EAST OF THE CASCADES.
&&
.AVIATION...WEAK INSTABILITY REMAINS OVER THE AREA INTO TONIGHT
WITH SCATTERED SHOWERS. THIS WILL RESULT IN A MIX BETWEEN MVFR AND
VFR CIGS BETWEEN NOW AND 5-6Z. THE CHANCE FOR MVFR CIGS WILL BE
HIGHER NEAR AND UNDER SHOWERS WITH MTNS PARTLY OBSCURED THROUGH
THIS EVENING. SHOWERS WILL CONTINUE TO DIMINISH TONIGHT BUT MVFR
CIGS ARE EXPECTED TO RETURN TO COASTAL AREAS AND THE UMPQUA VALLEY
THIS EVENING AND OVERNIGHT. IT WILL BE A CLOSE CALL IN THE ROGUE
VALLEY AND KLAMATH BASIN. GUIDANCE SUGGEST THERE IS THE POTENTIAL
FOR MVFR CIGS TO DEVELOP AFTER 08Z WHICH COULD BE THE RESULT OF
LINGERING LOW LEVEL MOISTURE. CONDITIONS SHOULD IMPROVE TO VFR AT
MOST LOCATIONS BY TOMORROW LATE MORNING. SK
&&
.PREV DISCUSSION... /ISSUED 252 PM PDT THU MAY 16 2013/
SHORT TERM...THE UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST
OVERNIGHT WITH THE MAIN ENERGY CONCENTRATED TO THE EAST OF THE
CASCADES. AS A RESULT SHOWERS WILL BE MORE PREVALENT FROM THE
KLAMATH/TULELAKE BASINS EAST WITH ONLY ISOLATED SHOWERS TO THE
WEST OF THE CASCADES. HIGH PRESSURE WILL BRIEFLY INTO THE AREA
FRIDAY BUT WITH PLENTY OF LOW LEVEL MOISTURE AND SLIGHTLY UNSTABLE
AIR MASS, SOME SHOWERS WILL LINGER ACROSS OUR FORECAST AREA
ESPECIALLY IN UPSLOPE AREA OF WEST TO NORTHWESTERLY FLOW. HIGH
TEMPERATURES WILL NUDGE UP A FEW DEGREES BUT SHOULD STILL BE A FEW
DEGREES BELOW SEASONAL NORMS. ANOTHER SHORT WAVE TROUGH WILL BRING
MORE SHOWERS TO THE AREA ON SATURDAY.
THE UPPER LEVEL RIDGE WILL BUILD INTO THE AREA SUNDAY AND MONDAY.
THIS WILL LEAD TO CLEARING AND WARMING WITH OFFSHORE EAST TO NORTHEAST
WINDS ACROSS SOUTHWEST OREGON AND NORTHERLY WINDS INTO THE
SACRAMENTO VALLEY FOR THE CALIFORNIA ZONES. THE FLOW IS EXPECTED
TO TURN ONSHORE MONDAY AFTERNOON IN RESPONSE TO THE NEXT LOW
PRESSURE THAT WILL AFFECT OUR WEATHER IN THE EXTENDED PERIOD. /FB
LONG TERM...CONFIDENCE IS HIGH AN UPPER LOW WILL DROP SOUTH INTO
THE PAC NW TUESDAY AND REMAINING THERE INTO THE END OF NEXT WEEK
WITH BELOW NORMAL TEMPERATURES AND POPS ABOVE CLIMO...ESPECIALLY
WEST OF THE CASCADES. CONFIDENCE IS NOT AS HIGH REGARDING THE
DETAILS ON THE EXACT POSITION OF THE UPPER LOW AND WHERE MOST OF THE
SIGNIFICANT PRECIPITATION WILL BE CENTERED AT. THIS MAY SEEM UNUSUAL
FOR THIS TIME OF THE YEAR...ESPECIALLY WITH THE RECENT WARM AND DRY
CONDITIONS WE HAVE EXPERIENCED THE PAST FEW WEEKS...HOWEVER THE
RETURN INTERVAL FOR THIS TYPE OF PATTERN DOES OCCUR EVERY 0-1 YEARS.
THE GOOD NEWS IS THAT IT COULD BRING THE POTENTIAL FOR MUCH NEEDED
PRECIPITATION. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
CC
000
FXUS66 KPDT 170332
AFDPDT
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
832 PM PDT THU MAY 16 2013
.UPDATE...CURRENT FORECAST REMAINS ON TRACK WITH LITTLE CHANGES.
UPPER LEVEL TROUGH CONTINUES TO LINGER OVER THE PACIFIC NORTHWEST.
SHOWERS AND A FEW ISOLATED THUNDERSTORMS HAVE RESULTED...AND ARE
EXPECTED AGAIN TOMORROW AFTERNOON AND EVENING. POPS HAVE BEEN
REDUCED SLIGHTLY FOR THE OVERNIGHT TO EARLY MORNING HOURS AS THE
ATMOSPHERE BRIEFLY STABILIZES. MODELS ARE STILL TARGETING THE
AFTERNOON INSTABILITY TO BE OVER THE MOUNTAINS OF NORTHEAST OREGON
TOMORROW. THEREFORE SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS
REMAIN IN THE FORECAST. WEBER
&&
.PREV DISCUSSION... /ISSUED 246 PM PDT THU MAY 16 2013/
SHORT TERM...UPDATE...A BROAD UPPER LEVEL TROUGH WILL LINGER OVER
THE WESTERN U.S. THROUGH FRIDAY. WEAK DISTURBANCES ROTATING THROUGH
THE TROUGH WILL KEEP VARYING AMOUNTS OF SHOWERS GOING THROUGH
FRIDAY. BEST CHANCES OF SHOWERS THROUGH TONIGHT WILL BE ACROSS
DESCHUTES COUNTY THIS EVENING, AND OVER CROOK AND GRANT COUNTIES
TONIGHT. A STRAY THUNDERSTORM MAY BE POSSIBLE LATE THIS AFTERNOON
INTO EARLY EVENING OVER THE NORTHERN BLUE MOUNTAINS AND WALLOWA
COUNTY. RAIN FALL HAS BEEN COOLING SURFACE TEMPS IN DESCHUTES
COUNTY, SO DO NOT EXPECT THUNDER THERE AT THIS TIME. BEST CHANCES OF
SHOWERS WILL SHIFT TO THE BLUE MOUNTAINS SOUTH TO GRANT COUNTY AND
EAST INTO WALLOWA COUNTY FRIDAY AS THE LAST WAVE PUSHES THE TROUGH
AXIS EAST TOWARDS IDAHO AND EASTERN NEVADA. THESE AREAS MAY ALSO SEE
ISOLATED THUNDERSTORMS IN THE AFTERNOON AND EVENING. SHOWER CHANCES
WILL DECREASE OVERNIGHT FRIDAY NIGHT INTO SATURDAY MORNING. ANOTHER
TROUGH WILL DIG INTO THE REGION SATURDAY AND SATURDAY NIGHT. THIS
SYSTEM WILL INCREASE SHOWER CHANCES, ESPECIALLY FROM THE BLUE
MOUNTAINS SOUTHWEST INTO CENTRAL OREGON SATURDAY AFTERNOON AND
EVENING. WINDS WILL INCREASE ACROSS THE BASIN, IN THE GORGE AND THE
KITTITAS VALLEY SATURDAY DUE TO THE ARRIVAL OF THIS NEXT TROUGH.
NORTHWEST FLOW WILL KEEP SOME SHOWERS GOING OVER THE MOUNTAINS ON
SUNDAY DUE TO UPSLOPE AFFECTS. OTHERWISE BUILDING HIGH PRESSURE WILL
DRY OUT THE LOWER ELEVATIONS. LOW TEMPS WILL RUN NEAR SEASONAL,
WHILE HIGH TEMPS WILL RUN NEAR OR SLIGHTLY BELOW SEASONAL THROUGH
THE PERIOD. 90
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...BOTH THE GFS AND ECMWF
ARE FORECASTING AN UPPER RIDGE PATTERN SUNDAY NIGHT WITH FAIR
CONDITIONS ACROSS MOST OF THE CWA. THE EXCEPTION WILL BE OVER THE
EASTERN ZONES WHERE THERE MAY BE SOME CLOUDINESS AND A FEW SHOWERS
FROM A DEPARTING WEATHER SYSTEM. THE HIGH PRESSURE ALOFT IS EXPECTED
TO PERSIST THROUGH MONDAY. AFTER THAT THE NEXT WEATHER SYSTEM WILL
BEGIN TO MOVE INTO THE PACIFIC NORTHWEST. THE GFS MODEL WANTS TO
BRING IN THE TROUGH FIRST WHILE THE ECMWF KEEPS AN UPPER RIDGE OVER
THE CWA ON MONDAY. HOWEVER BOTH MODELS COME INTO PHASE WITH THE
DEVELOPMENT OF A LARGE CLOSED UPPER LOW BY LATE TUESDAY WITH THE GFS
MUCH FURTHER SOUTH THAN THE ECMWF WITH THE POSITION OF THE UPPER
LOW. THE ECMWF HAS BEEN HAVING A BETTER TRACK RECORD DURING THE
RECENT FEW SYSTEMS AND THEREFORE AM LEANING TOWARD THE ECMWF
SOLUTION WITH THE LOW FURTHER NORTH ALONG THE BC COAST. THIS WILL
CAUSE A SOUTHWEST FLOW OVER THE CWA WHICH WILL HELP TO TRANSPORT
MOISTURE AND INCREASING INSTABILITY OVER THE REGION. HOWEVER...BOTH
SOLUTIONS MEANS A COOLING TREND WHICH WILL TAKE PLACE WITH FALLING
HEIGHTS AND THICKNESSES...ESPECIALLY THE GFS AS THE UPPER LOW CENTER
COMES MUCH CLOSER TO THE AREA. THIS PATTERN OF UPPER LOWS WILL
PERSIST THROUGHOUT THE REMAINDER OF THE EXTENDED FORECAST PERIOD...
THOUGH WITH VERY SIGNIFICANT DIFFERENCES IN THE PLACEMENT OF THE
UPPER LOWS BETWEEN THESE TWO MODELS. AS SUCH DID NOT MAKE TOO MANY
CHANGES IN THE EXTENDED FORECAST PERIOD DUE TO THE UNCERTAINTY.
HOWEVER THERE IS BETTER AGREEMENT BETWEEN THE TWO MODELS BY THURSDAY
AND THEN THE MODELS DIVERGE AGAIN FURTHER OUT IN THE EXTENDED
FORECAST PERIOD WITH THE ECMWF BEING MUCH MORE ORGANIZED AND DEEPER
THAN THE GFS AND AM LEANING TOWARD THAT SCENARIO. THE RESULT WILL BE
COOL CONDITIONS WITH PERIODIC SHOWERS. EVEN THOUGH TEMPERATURES WILL
BE ON THE COOL SIDE THEY WILL NOT BE MUCH COOLER THAN NORMAL AND IN
FACT THEY WILL BE CLOSE TO NORMAL FOR THIS TIME OF YEAR. 88
AVIATION...06Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL OVER
THE NEXT 24 HOURS. HOWEVER...SOME TAF SITES MAY EXPERIENCE BRIEF
MVFR CONDITIONS DUE TO LOWERED CIGS FROM SHOWERS. SHOWERS WILL
TAPER OFF OVERNIGHT TONIGHT AND PICK BACK UP TOMORROW LATE MORNING
TO EARLY AFTERNOON. WINDS WILL BE BREEZY AFTER 21Z AT JUST ABOUT
ALL TAF SITES OTHER THAN KPSC AND KYKM. EXPECT WINDS 5 TO 15KTS
WITH 20 TO 25KTS AT TIMES. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 50 70 47 68 / 10 20 20 20
ALW 53 72 50 70 / 20 20 20 20
PSC 52 77 49 76 / 10 10 10 10
YKM 47 74 44 72 / 10 10 10 20
HRI 50 75 48 74 / 10 10 10 20
ELN 49 71 48 68 / 20 10 10 20
RDM 42 64 38 63 / 40 20 10 30
LGD 46 64 44 62 / 20 40 30 20
GCD 43 66 41 64 / 40 50 30 20
DLS 53 71 49 68 / 30 10 10 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
FRIDAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
89/88/89
000
FXUS66 KPQR 170319
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
813 PM PDT THU MAY 16 2013
.SYNOPSIS...WEAK LOW PRESSURE OFFSHORE CONTINUES TO SPREAD SHOWERS
ACROSS WESTERN OREGON THIS EVENING. THIS SYSTEM WILL WEAKEN FOR
DECREASING SHOWERS FRIDAY. TRANSITORY HIGH PRESSURE MAY BRING A
BRIEF BREAK IN THE SHOWERS FRIDAY NIGHT BEFORE THE NEXT SYSTEM BRINGS
ANOTHER DECENT CHANCE FOR RAIN SATURDAY AND LINGERING SHOWERS SUNDAY.
DRIER WEATHER IS EXPECTED SUN NIGHT/MON...BUT IT IS LOOKING MORE
LIKELY THAT A COOL AND UNSETTLED PATTERN WILL SET UP OVER THE PACIFIC
NORTHWEST FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH SUNDAY...SHOWERS CONTINUE TO SPREAD
NORTH THROUGH THE VALLEY AND ALONG THE CASCADES...WITH SOME DRIZZLE
ALONG THE COAST AS WELL. THESE HAVE GENERALLY BECOME LIGHTER THAN
THOSE SEEN EARLIER IN THE DAY...AND LIGHTNING HAS BEEN CONFINED JUST
EAST OF THE CASCADE CREST IN SW WASHINGTON...MAINLY NEAR GOLDENDALE.
THAT SAID WITH RELATIVELY HIGH MOISTURE CONTENT...STRONGER SHOWERS
WILL OCCASIONALLY PRODUCE HEAVIER DOWNPOURS...ESPECIALLY THIS
EVENING. WV/IR IMAGERY SHOWS THE DEFORMATION BAND ASSOCIATED WITH
THE UPPER TROUGH PIVOTING OVER THE AREA WHILE THE BASE OF THE UPPER
TROUGH HEADS INTO SW OR/NW CA. SCATTERED SHOWERS WILL CONTINUE
TONIGHT...AND HAVE TRIED TO ACCENTUATE THE POP FORECAST THE N OR/S
WA CASCADES AND THE NORTH VALLEY AND BACK NW INTO COWLITZ COUNTY AND
THE WILLAPA HILLS AS THE DEFORMATION AXIS BECOMES SE-NW ORIENTED.
EXPECT ENOUGH MOISTURE AND INSTABILITY ON FRIDAY DUE TO UPPER TROUGH
LINGERING ACROSS THE PAC NW AND NOTHING TO SCOUR OUT THE LOWER LEVEL
MOISTURE. KMD
REST OF THE SHORT TERM DISCUSSION UNCHANGED...NAM BUFR SOUNDINGS SHOW
EVEN SHALLOWER INSTABILITY FRIDAY AS THE CAPPING INVERSION LOWERS TO
600-700 MB. THIS WILL LIMIT SHOWERS FRIDAY DESPITE A LITTLE MORE
SUNSHINE...BUT THERE WILL STILL BE ENOUGH INSTABILITY FOR SCATTERED
SHOWERS THROUGHOUT THE DAY. THESE WILL DISSIPATE FRI EVENING AS HIGH
PRESSURE MAY BRING A BRIEF BREAK IN THE PRECIPITATION. HOWEVER THE
NEXT SYSTEM NOW NEAR 150W WILL LIKELY SPREAD RAIN BACK ACROSS THE
DISTRICT SATURDAY. AS ADVERTISED IN THE MORNING DISCUSSION WE RAISED
POPS QUITE A BIT FOR SATURDAY AS A RESULT. QPF SHOULD BE MODEST WITH
AROUND 0.25 INCH IN THE VALLEYS AND UP TO 1 INCH IN THE HIGHER
TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH A FEW
LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER A LITTLE BELOW NORMAL THROUGH THE WEEKEND.
SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES.WEAGLE
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...AFTER A BRIEF BREAK OF
POTENTIALLY SUNNY AND SEASONABLE WEATHER MONDAY...IT APPEARS AN
EXTENDED COOL AND UNSETTLED PERIOD IS BECOMING INCREASINGLY LIKELY
FOR MIDWEEK. MODELS ARE SHOWING RELATIVELY GOOD AGREEMENT THAT A COLD
AND CLOSED UPPER LOW WILL DIG DOWN FROM ALASKA...SETTLING SOMEWHERE
NEAR THE PAC NW TUE AND LINGERING THROUGH THURSDAY. COLD AIR ALOFT
WILL KEEP THE AIR MASS UNSTABLE...WITH COOL SHOWERY WEATHER AND
POSSIBLY EVEN A THUNDERSTORM OR TWO DEPENDING ON HOW THINGS EVOLVE.
FAIRLY HIGH DEGREE OF CONFIDENCE OF BELOW NORMAL TEMPS DURING THIS
PERIOD ALONG WITH HIT AND MISS SHOWERS. SNOW LEVELS MAY VERY WELL GET
BELOW THE PASSES...BUT WE WILL PLAY IT CONSERVATIVE FOR NOW WITH SNOW
LEVELS BOTTOMING OUT AROUND 4000-4500 FT MIDWEEK. IF MODELS CONTINUE
TO BRING THE CENTER OF THE COLD POOL OVER THE PAC NW...THESE SNOW
LEVELS WILL NEED TO COME DOWN A BIT AND POSSIBLY AS LOW AS 2000-3000
FEET. WEAGLE
&&
.AVIATION...SHOWERY AIR MASS OVER REGION THIS EVENING...WITH
GENERALLY VFR CONDITIONS. FEW ISOLATED TSTORMS OVER UNTIL 06Z.
SHOWERS WILL DECREASE OVERNIGHT...BUT EXPECT LOWER CLOUDS TO
FORM. SEEMS LIKELY THAT WILL HAVE MIX OF MVFR AND LOW VFR CIGS
INTO FRI...BUT WITH MOIST MILD AIR MASS SEEMS GOOD BET THAT MVFR
WILL BECOME MORE WIDESPREAD BETWEEN 09Z AND 11Z...AND PERSIST WELL
INTO FRI AM.
KPDX AND APPROACHES...VFR CONDITIONS WITH SCATTERED SHOWERS
THROUGH 07Z. AFTERWARDS...MIX OF LOW VFR AND MVFR CIGS...MOSTLY
AT 2000 TO 2500 FT LATER TONIGHT INTO FRI AM. SHOULD RETURN TO VFR
CIGS BY 20Z FRI AS AIR MASS DESTABILIZES A BIT. ROCKEY.
&&
.MARINE...WEAK LOW PRES OVER THE COASTAL WATERS TONIGHT AND FRI.
THIS KEEPS WINDS 10 TO 15 KT RANGE...WITH SEAS NEAR 5 FT.
A WEAK FRONT WILL PUSH ACROSS THE REGION ON SAT...BUT WINDS TO
REMAIN BELOW 20 KT. ONCE THAT FRONT CLEARS THE REGION SAT NIGHT AND
SUN...HIGH PRES WILL BUILD OVER NE PAC WITH RETURN OF N TO NW WINDS.
THESE WINDS MAY GUST 20 TO 25 KT OVER THE CENTRAL OREGON COASTAL
WATERS ON SUN AND SUN NIGHT. SEAS EXPECTED TO STAY IN THE 4 TO 7 FT
RANGE THIS WEEKEND.
&&
.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.
000
FXUS66 KPQR 170315
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
813 PM PDT THU MAY 16 2013
.SYNOPSIS...WEAK LOW PRESSURE OFFSHORE CONTINUES TO SPREAD SHOWERS
ACROSS WESTERN OREGON THIS EVENING. THIS SYSTEM WILL WEAKEN FOR
DECREASING SHOWERS FRIDAY. TRANSITORY HIGH PRESSURE MAY BRING A
BRIEF BREAK IN THE SHOWERS FRIDAY NIGHT BEFORE THE NEXT SYSTEM BRINGS
ANOTHER DECENT CHANCE FOR RAIN SATURDAY AND LINGERING SHOWERS SUNDAY.
DRIER WEATHER IS EXPECTED SUN NIGHT/MON...BUT IT IS LOOKING MORE
LIKELY THAT A COOL AND UNSETTLED PATTERN WILL SET UP OVER THE PACIFIC
NORTHWEST FOR THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...TONIGHT THROUGH SUNDAY...SHOWERS CONTINUE TO SPREAD
NORTH THROUGH THE VALLEY AND ALONG THE CASCADES...WITH SOME DRIZZLE
ALONG THE COAST AS WELL. THESE HAVE GENERALLY BECOME LIGHTER THAN
THOSE SEEN EARLIER IN THE DAY...AND LIGHTNING HAS BEEN CONFINED JUST
EAST OF THE CASCADE CREST IN SW WASHINGTON...MAINLY NEAR GOLDENDALE.
THAT SAID WITH RELATIVELY HIGH MOISTURE CONTENT...STRONGER SHOWERS
WILL OCCASIONALLY PRODUCE HEAVIER DOWNPOURS...ESPECIALLY THIS
EVENING. WV/IR IMAGERY SHOWS THE DEFORMATION BAND ASSOCIATED WITH
THE UPPER TROUGH PIVOTING OVER THE AREA WHILE THE BASE OF THE UPPER
TROUGH HEADS INTO SW OR/NW CA. SCATTERED SHOWERS WILL CONTINUE
TONIGHT...AND HAVE TRIED TO ACCENTUATE THE POP FORECAST THE N OR/S
WA CASCADES AND THE NORTH VALLEY AND BACK NW INTO COWLITZ COUNTY AND
THE WILLAPA HILLS AS THE DEFORMATION AXIS BECOMES SE-NW ORIENTED.
EXPECT ENOUGH MOISTURE AND INSTABILITY ON FRIDAY DUE TO UPPER TROUGH
LINGERING ACROSS THE PAC NW AND NOTHING TO SCOUR OUT THE LOWER LEVEL
MOISTURE. KMD
REST OF THE SHORT TERM DISCUSSION UNCHANGED...NAM BUFR SOUNDINGS SHOW
EVEN SHALLOWER INSTABILITY FRIDAY AS THE CAPPING INVERSION LOWERS TO
600-700 MB. THIS WILL LIMIT SHOWERS FRIDAY DESPITE A LITTLE MORE
SUNSHINE...BUT THERE WILL STILL BE ENOUGH INSTABILITY FOR SCATTERED
SHOWERS THROUGHOUT THE DAY. THESE WILL DISSIPATE FRI EVENING AS HIGH
PRESSURE MAY BRING A BRIEF BREAK IN THE PRECIPITATION. HOWEVER THE
NEXT SYSTEM NOW NEAR 150W WILL LIKELY SPREAD RAIN BACK ACROSS THE
DISTRICT SATURDAY. AS ADVERTISED IN THE MORNING DISCUSSION WE RAISED
POPS QUITE A BIT FOR SATURDAY AS A RESULT. QPF SHOULD BE MODEST WITH
AROUND 0.25 INCH IN THE VALLEYS AND UP TO 1 INCH IN THE HIGHER
TERRAIN. RAIN WILL TAPER TO SHOWERS SATURDAY NIGHT WITH A FEW
LINGERING INTO SUNDAY...MAINLY OVER THE HIGHER TERRAIN.
TEMPERATURES WILL HOVER A LITTLE BELOW NORMAL THROUGH THE WEEKEND.
SNOW LEVELS SHOULD REMAIN ABOVE THE PASSES THROUGHOUT THE
WEEKEND...BUT MAY GET AS LOW AS 4500-5000 FT AT TIMES.WEAGLE
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...AFTER A BRIEF BREAK OF
POTENTIALLY SUNNY AND SEASONABLE WEATHER MONDAY...IT APPEARS AN
EXTENDED COOL AND UNSETTLED PERIOD IS BECOMING INCREASINGLY LIKELY
FOR MIDWEEK. MODELS ARE SHOWING RELATIVELY GOOD AGREEMENT THAT A COLD
AND CLOSED UPPER LOW WILL DIG DOWN FROM ALASKA...SETTLING SOMEWHERE
NEAR THE PAC NW TUE AND LINGERING THROUGH THURSDAY. COLD AIR ALOFT
WILL KEEP THE AIR MASS UNSTABLE...WITH COOL SHOWERY WEATHER AND
POSSIBLY EVEN A THUNDERSTORM OR TWO DEPENDING ON HOW THINGS EVOLVE.
FAIRLY HIGH DEGREE OF CONFIDENCE OF BELOW NORMAL TEMPS DURING THIS
PERIOD ALONG WITH HIT AND MISS SHOWERS. SNOW LEVELS MAY VERY WELL GET
BELOW THE PASSES...BUT WE WILL PLAY IT CONSERVATIVE FOR NOW WITH SNOW
LEVELS BOTTOMING OUT AROUND 4000-4500 FT MIDWEEK. IF MODELS CONTINUE
TO BRING THE CENTER OF THE COLD POOL OVER THE PAC NW...THESE SNOW
LEVELS WILL NEED TO COME DOWN A BIT AND POSSIBLY AS LOW AS 2000-3000
FEET. WEAGLE
&&
.AVIATION...SHOWERY AIR MASS OVER REGION THIS EVENING...WITH
GENERALLY VFR CONDITIONS. FEW ISOLATED TSTORMS OVER UNTIL 06Z.
SHOWERS WILL DECREASE OVERNIGHT...BUT EXPECT LOWER CLOUDS TO
FORM. SEEMS LIKELY THAT WILL HAVE MIX OF MVFR AND LOW VFR CIGS
INTO FRI...BUT WITH MOIST MILD AIR MASS SEEMS GOOD BET THAT MVFR
WILL BECOME MORE WIDESPREAD BETWEEN 09Z AND 11Z...AND PERSIST WELL
INTO FRI AM.
KPDX AND APPROACHES...VFR CONDITIONS WITH SCATTERED SHOWERS
THROUGH 07Z. AFTERWARDS...MIX OF LOW VFR AND MVFR CIGS...MOSTLY
AT 2000 TO 2500 FT LATER TONIGHT INTO FRI AM. SHOULD RETURN TO VFR
CIGS BY 20Z FRI AS AIR MASS DESTABILIZES A BIT. ROCKEY.
&&
.MARINE...WEAK LOW PRES OVER THE COASTAL WATERS TONIGHT AND FRI.
THIS KEEPS WINDS 10 TO 15 KT RANGE...WITH SEAS NEAR 5 FT.
ANOTHER FRONT ARRIVES SAT...WITH WINDS PICKING UP A BIT AGAIN BUT
LOOKS AS IF WINDS REMAIN 20 KT OR LESS...BUT PERHAPS MAY REACH 20
TO 25 KT OVER THE N COASTAL WATERS SAT NIGHT. SEAS EXPECTED TO
STAY IN THE 4 TO 7 FT RANGE THIS WEEKEND.
&&
.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.
000
FXUS65 KBOI 170258
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
858 PM MDT THU MAY 16 2013
.DISCUSSION...SCATTERED SHOWERS HAVE BEEN FOCUSED OVER SE OREGON
AND HIGHER TERRAIN SOUTH OF THE SNAKE RIVER IN IDAHO THIS EVENING
DROPPING A WETTING RAIN /A TENTH OF AN INCH OR MORE/ ON SOME
LOCATIONS. THE LAST FEW HOURS HAVE SEEN AN INCREASE IN SHOWERS
MAKING IT INTO THE SNAKE RIVER VALLEY AND SOUTHERN BOISE MTNS BUT
MOST SITES HAVE YET TO MEASURE. THE 00Z WEATHER BALLOON LAUNCHED
FROM BOISE SHOWED A STABLE ENVIRONMENT OVER THE VALLEY WHICH IS
CONTRIBUTING TO THE DISSIPATION OF PRECIPITATION AS IT MOVES OFF
THE HIGHER TERRAIN TO THE SOUTH. WITH THE TROUGH AXIS STILL OVER
WESTERN OREGON THIS EVENING SHOWERS WILL CONTINUE THROUGH THE
NIGHT AND INTO FRIDAY. THE THUNDERSTORM THREAT HAS DIMINISHED FOR
THIS EVENING ESPECIALLY OVER IDAHO. THE DYNAMICS AHEAD OF THE
TROUGH COULD FUEL DEEPER CONVECTION THAT PUTS DOWN A STRIKE OR
TWO OVER HARNEY COUNTY TONIGHT...BUT NOT CONFIDENT ENOUGH TO
INCLUDE IT IN THE FORECAST AT THIS TIME. SOME UPDATES TO THE
CURRENT FORECAST TO INCREASE CHANCE OF PRECIPITATION OVER SE
OREGON ZONES FOR TONIGHT AND TO TAKE OUT MENTION OF THUNDER FOR
THIS EVENING. REST OF FORECAST LOOKS GOOD FOR TONIGHT WITH
SCATTERED SHOWERS IN LOWER VALLEYS AND GREATER COVERAGE IN THE
MTNS.
&&
.AVIATION...VFR. WIDESPREAD SHOWERS CONTINUING THROUGH FRIDAY. BRIEF
MVFR CEILINGS WITH THE STRONGER SHOWERS. CEILINGS WILL BE ABOVE 5000
FEET. SURFACE WINDS WILL BE WEST TO NORTHWEST 5 TO 15 KTS. WINDS
ALOFT WILL BE MAINLY WESTERLY AT 10 TO 20 KTS.
WEEKEND OUTLOOK...MAINLY VFR WITH SCATTERED SHOWERS AND A SLIGHT
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS. AN UPPER LEVEL TROUGH
WILL BRING COOLER AND CLOUDY WEATHER FOR MOST OF THE WEEKEND..
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH SATURDAY...UPPER TROUGH CONTINUES TO
MOVE ONSHORE THIS AFTERNOON. MOISTURE STREAMING IN FROM THE
SOUTHWEST AHEAD OF THE TROUGH...COMBINED WITH INSTABILITY...WAS
RESULTING IN SCATTERED SHOWERS MAINLY TO THE SOUTH AND EAST OF
BOISE. ISOLATED THUNDERSTORMS WERE DEVELOPING OVER THE CENTRAL ID
MTNS. ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP EAST OF IDAHO
CITY AND MCCALL...AND ALONG THE NEVADA BORDER...THROUGH THIS
EVENING. SHOWERS WILL CONTINUE OVERNIGHT AND INTO FRIDAY AS THE
UPPER TROUGH MOVES INTO EASTERN OREGON BY THE AFTERNOON. MARGINAL
INSTABILITY STILL WARRANTS A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS ACROSS MUCH OF THE AREA. THE TROUGH WILL WEAKEN AND
MOVE GRADUALLY TO OUR EAST FRIDAY NIGHT AND SATURDAY AS ANOTHER
TROUGH ENTERS THE PACIFIC NORTHWEST. SHOWERS WILL DIMINISH WITH THE
DEPARTING TROUGH AS THE NEXT TROUGH BRINGS A SLIGHT CHANCE OF
SHOWERS BACK INTO SE OREGON SATURDAY AFTERNOON. ONCE AGAIN...AIR
MASS WILL BE JUST UNSTABLE ENOUGH TO WARRANT A SLIGHT CHANCE OF
AFTERNOON THUNDERSTORMS. TEMPERATURES WILL REMAIN SLIGHTLY BELOW
NORMAL. WINDS WILL BE PRIMARILY LIGHT...EXCEPT BECOMING LOCALLY
BREEZY SATURDAY AFTERNOON IN THE UPPER TREASURE AND WESTERN MAGIC
VALLEYS.
LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...A SHORT WAVE TROUGH
WILL MOVE DOWN THE BACK SIDE OF THE DEPARTING LONG WAVE TROUGH
SATURDAY NIGHT...BRINGING ANOTHER ROUND OF SHOWERS TO THE MOUNTAINS
AND A REINFORCING SHOT OF COOLER AIR TO THE ENTIRE REGION. HIGHS
SUNDAY WILL BE 5 TO 10 DEGREES BELOW NORMAL. MONDAY WILL BE DRY AND
SLIGHTLY WARMER. A RIDGE WILL BUILD IN FOR TUESDAY...BRINGING DRYING
AND NEAR NORMAL TEMPS...BEFORE A LARGE STRONG CUTOFF LOW MOVES
TOWARD THE AREA TUESDAY NIGHT THROUGH THURSDAY. THIS LARGE LOW WILL
PROVIDE SOUTHWEST WINDS ALOFT TUE...PUSHING HIGHS BACK ABOVE NORMAL.
HOWEVER...AS THE LOW NEARS AND HEIGHTS FALL...TEMPS WILL COME BACK
BELOW NORMAL WED AND THU. SHOWERS WILL BECOME MORE NUMEROUS TUE
NIGHT THROUGH THU. A SLIGHT CHANCE OF THUNDERSTORMS IS IN THE
FORECAST BOTH SUNDAY AND TUESDAY FOR THE AFTERNOON AND EVENING HOURS.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...DG
AVIATION.....JS
PREV SHORT TERM...BW
PREV LONG TERM....SP/CB
|
