Special Weather Statement, NWS Pendleton, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
155 PM PDT THU AUG 4 2011

.SHORT TERM...TONIGHT THROUGH SUNDAY. ISOLATED THUNDERSTORMS
CONTINUE TO DEVELOP OVER FAR EASTERN OREGON THIS AFTERNOON.  BASED
ON WSR-88D...STORMS HAVE BEEN WEAK WITH A FEW CELLS IN THE 40-50 DBZ
RANGE BUT NOTHING MORE.  ALTHOUGH CELL MOVEMENT HAS BEEN
SLOW...THERE DOESN'T APPEAR TO BE ANY HEAVY DOWNPOURS ASSOCIATED
WITH THEM.  MODELS HAVE DONE A DECENT JOB DETECTING THIS MID LEVEL
CIRCULATION ALONG THE OR/ID BORDER.  AS THE MAIN UPPER TROUGH SHIFTS
EASTWARD...THE SMALL DISTURBANCE WILL MOVE INTO IDAHO.
THUNDERSTORMS WILL DIMINISH OVERNIGHT DUE TO LACK OF HEATING AND A
DRIER WESTERLY FLOW BEHIND THE UPPER TROUGH.  ONE CHANGE TO THE
FORECAST WAS TO REMOVE THE ISOLATED THUNDERSTORMS FOR THE EAST
SLOPES OF THE WASHINGTON AND NRN OREGON CASCADES.  A WEAK MARINE
PUSH AND THE WESTERLY FLOW HAS BROUGHT MORE STABLE CONDITIONS TO
THIS AREA.

WASHINGTON AND OREGON WILL GENERALLY LIE UNDER A WEAK CYCLONIC FLOW
ALOFT THROUGH THE REMAINDER OF THE SHORT TERM PERIOD.  BELIEVE
ISOLATED THUNDERSTORMS WILL DEVELOP DURING THE AFTERNOON AND EVENING
HOURS OVER CENTRAL AND EASTERN OREGON WHILE MOST OF EASTERN
WASHINGTON AND NORTH CENTRAL OREGON REMAIN UNDER A DRY WESTERLY
FLOW.  STORMS WILL PRIMARILY BE DIURNALLY DRIVEN AND WEAK WITH
LITTLE TO NO THREAT OF STRONG OR SEVERE STORMS.  TEMPERATURES WILL
VARY LITTLE FROM DAY TO DAY AND WILL REMAIN NEAR SEASONAL AVERAGE.
JOHNSON

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY.  A TROUGH REMAINS JUST
OFFSHORE THROUGH THE EARLY PART OF THE EXTENDED...BUT THERE IS
LITTLE IN THE WAY OF MOISTURE OR INSTABILITY.  BY TUESDAY...BOTH THE
ECMWF AND THE GFS SHOW MORE DRY WEST TO NORTHWEST FLOW AS THE HIGH
PRESSURE OVER THE SOUTHWEST U.S. TRIES TO EDGE NORTH AND THE TROUGH
IS PUSH BACK INTO SOUTHERN CANADA.  TEMPERATURES WILL BE NEAR
SEASONAL VALUES. ML

&&

.AVIATION...00Z TAFS.  VFR CONDITIONS WILL PREVAIL AT ALL SITE
THROUGH THE NEXT 24 HOURS.  UPPER LEVEL TROUGH WILL BE MOVING INTO
IDAHO THIS EVENING WITH SOME ISOLATED THUNDERSTORMS OVER THE BLUE
AND WALLOWA MOUNTAINS.  THERE MAY BE SOME CUMULUS BUILD UPS AND
HIGHER CLOUDS AT KRDM...KBND...KPDT AND KALW THROUGH 04Z FOLLOWED BY
MAINLY SKIES OVERNIGHT.  KDLS WILL SEE GUSTY WINDS TO 20 KTS THROUGH
05Z WITH WINDS 5 TO 15 KTS AT OTHER SITES. ML

&&

.FIRE WEATHER...STORM PERFORMANCE ON TRACK WITH EXPECTATIONS IF NOT
UNDER-PERFORMING A BIT ON THUNDERSTORM CELL COVERAGE. STORMS THUS
FAR HAVE BEEN PRODUCING ONLY A FEW CLOUD-TO-GROUND STRIKES WITH EACH
ONE. STILL BELIEVE ADDITIONAL STORMS WILL DEVELOP OVER TOWARDS THE
CENTRAL OREGON CASCADES THIS AFTERNOON AND EVENING AS WE ARE
APPROACHING PEAK HEATING AND WILL THUS KEEP GUARD UP AGAINST MORE
SIGNIFICANT LIGHTNING DEVELOPMENT.

WINDS WILL CONTINUE A MINOR INCREASE THROUGH THE GORGE AND WESTERN
BASIN HEADING INTO THE EVENING AND BEGIN CARRYING TO THE
SOUTHERN BASIN TOWARDS THE LATE AFTERNOON AND EVENING. HUMIDITIES
AREA BEING MODERATED BY THE INCREASED DEW POINTS THOUGH. /JBONK

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  60  89  57  87 /  20  10  10  10
ALW  64  91  62  87 /  20  10  10  10
PSC  63  93  59  89 /  10   0   0   0
YKM  59  90  58  85 /  10   0   0   0
HRI  64  91  60  88 /  10  10  10   0
ELN  61  88  59  84 /  10   0   0   0
RDM  52  86  50  86 /  20  10  10  10
LGD  58  86  54  84 /  40  20  20  20
GCD  56  86  54  83 /  30  20  20  20
DLS  62  85  61  86 /  10   0   0   0

&&

.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

85/93/93

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
509 AM PDT THU AUG 4 2011

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
051215-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-WALLOWA COUNTY-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-JOHN DAY BASIN-OCHOCO-
JOHN DAY HIGHLANDS-
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON-
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON-
EAST SLOPES OF THE OREGON CASCADES-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS OF WASHINGTON-
EAST SLOPES OF THE WASHINGTON CASCADES-SIMCOE HIGHLANDS-
509 AM PDT THU AUG 4 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS
     EAST SLOPES OF THE WASHINGTON CASCADES, SIMCOE HIGHLANDS,
     KITTITAS VALLEY, YAKIMA VALLEY, LOWER COLUMBIA BASIN OF
     WASHINGTON, FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON,
     NORTHWEST BLUE MOUNTAINS OF WASHINGTON, NORTH CENTRAL OREGON,
     EAST SLOPES OF THE OREGON CASCADES, LOWER COLUMBIA BASIN OF
     OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY, FOOTHILLS OF THE
     NORTHERN BLUE MOUNTAINS OF OREGON, NORTHERN BLUE MOUNTAINS OF
     OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON, FOOTHILLS OF THE
     SOUTHERN BLUE MOUNTAINS OF OREGON, JOHN DAY BASIN, OCHOCO-JOHN
     DAY HIGHLANDS

AN WEATHER DISTURBANCE CURRENTLY OFF THE COAST WILL MOVE INLAND
TODAY WHICH WILL COMBINE WITH AFTERNOON HEATING AND AVAILABLE
MOISTURE AND INSTABILITY TO GENERATE AFTERNOON AND EVENING
THUNDERSTORMS IN THE AREAS LISTED ABOVE. MOST THUNDERSTORMS WILL
BE WEAK...THOUGH STRONG THUNDERSTORMS ARE POSSIBLE WITH SMALL
HAIL...GUSTY WINDS AND BRIEF HEAVY RAIN. ELSEWHERE VERY WARM AND
DRY CONDITIONS WILL PERSIST.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS FRIDAY
     FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON, NORTHWEST BLUE
     MOUNTAINS OF WASHINGTON, NORTH CENTRAL OREGON, EAST SLOPES OF
     THE OREGON CASCADES, GRANDE RONDE VALLEY, WALLOWA COUNTY,
     FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON, NORTHERN
     BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON, JOHN DAY
     BASIN, OCHOCO-JOHN DAY HIGHLANDS

THE UNSETTLED WEATHER WILL CONTINUE FRIDAY AND SATURDAY WITH
AFTERNOON AND EVENING THUNDERSTORMS AGAIN IN THE AREAS LISTED
ABOVE. AGAIN THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE..BUT
THEY COULD BECOME STRONG WITH SMALL HAIL...GUSTY WINDS AND BRIEF
HEAVY RAIN. ELSEWHERE THE VERY WARM AND DRY CONDITIONS WILL
PERSIST.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:

WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PENDLETON OR
339 PM PDT THU AUG 4 2011

ORZ506-042345-
OCHOCO-JOHN DAY HIGHLANDS OR-
339 PM PDT THU AUG 4 2011

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN CROOK COUNTY IN
CENTRAL OREGON...AND EXTREME SOUTHWESTERN GRANT COUNTY IN EAST
CENTRAL OREGON UNTIL 445 PM PDT...

AT 330 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 18 MILES SOUTH OF SUPLEE...OR 40 MILES NORTHWEST
OF BURNS...MOVING NORTH AT 5 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER IS EXPECTED WITH THIS STORM...
ALONG WITH HEAVY RAIN.

LAT...LON 4371 11987 4396 12004 4404 11958 4395 11959
      4395 11977 4374 11976
TIME...MOT...LOC 2238Z 163DEG 3KT 4383 11979

DC