Funnel Clouds in Oregon, May 26, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1052 AM PDT MON MAY 26 2008

.SHORT TERM...FORECAST ON TRACK AND NO UPDATES PLANNED.  A
PERSISTENT AND BROAD UPPER TROUGH OVER THE EASTERN PACIFIC AND
WESTERN U.S. WILL CONTINUE TO ROTATE A SERIES OF WAVES ACROSS THE
FORECAST AREA TODAY AND TONIGHT.  A MID LEVEL WAVE IS CURRENTLY OVER
NORTH CENTRAL OREGON SLOWLY MOVING SW.  IT IS DIFFICULT TO LOCATE
ANY ADDITIONAL WAVES IN THE FORECAST AREA ON SATELLITE AND ON
MODELS.  HOWEVER...THE AIR MASS IS MOIST AND UNSTABLE SO THE
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOR TODAY SEEM
REASONABLE.  THERE APPEARS TO BE LESS CLOUD COVER TODAY...THUS
TEMPERATURES WILL BE AT LEAST A FEW DEGREES WARMER COMPARED TO
YESTERDAY.

&&

.AVIATION...18Z TAFS...ALL TAF SITES EXCEPT KRDM WILL SEE GENERALLY
VFR CIGS/VIS THROUGH THE PERIOD. CIGS WILL MAINLY VARY BETWEEN 5000
AND 10000 FEET AGL AT KYKM...KPSC...KDLS...KALW AND KPDT AFTER 26/20
UTC. MEANWHILE INTERMITTENT MVFR CIGS AT KRDM WILL CONTINUE THROUGH
THIS AFTERNOON...THEN AGAIN BECOME PREVAILING OVERNIGHT. THE AIR
MASS OVER THE REGION REMAINS MOIST AND UNSTABLE...SO ISOLATED TO
SCATTERED SHOWERS WILL AGAIN DEVELOP THIS AFTERNOON. FOR NOW
SPECIFIC OCCURRENCE OF SHOWER TIMING IS UNCERTAIN AT MOST TAF SITES
AND WILL GO WITH VICINITY SHOWERS. THESE SHOWERS COULD LOWER CIG/VIS
VALUES INTO THE MVFR RANGE BRIEFLY IF THEY MOVE OVER AN AIRFIELD. A
WEAK DISTURBANCE SLIDING INTO WEST CENTRAL OREGON MAY BRING A MORE
CONSOLIDATED BAND OF SHOWERS TO NEAR KRDM...AND WILL THEREFORE
ATTEMPT TO TIME SOME SHOWERS THERE. THUNDERSTORM THREAT WILL AGAIN
BE ISOLATED POP UP TYPE STORMS AND WILL THEREFORE GO WITH THE CB
CLOUD INDICATOR FOR NOW TO SHOW STRONGER CONVECTIVE POTENTIAL. 90

&&

.PREV DISCUSSION... /ISSUED 215 AM PDT MON MAY 26 2008/

SHORT TERM...TODAY THROUGH WEDNESDAY...NUMEROUS WAVES OF ENERGY
CONTINUE TO ROTATE AROUND A VERY PERSISTENT AND WET UPPER LOW
PRESSURE SYSTEM. THE WRAP FLOW ON THE NORTH AND NORTHEAST SIDE OF
THE LOW WILL CONTINUE TO BRING PERIODIC SURGES OF MOISTURE INTO THE
FORECAST AREA FOR AT LEAST THE NEXT SEVERAL DAYS. THESE SURGES OF
MOISTURE WILL CAUSE SHORT PERIODS OF STEADY RAINFALL...HOWEVER MOST
OF THE PRECIPITATION WILL BE OF THE CONVECTIVE SHOWERY TYPE. THE
ATMOSPHERE WILL BECOME UNSTABLE IN THE AFTERNOONS AND EVENINGS EACH
DAY AS SURFACE HEATING TAKES PLACE DUE SOME BREAKS IN THE OVERCAST
WHICH WILL ALLOW SOME SUNSHINE TO INTENSIFY THE SURFACE HEATING. IN
ADDITION THE ATMOSPHERE WILL ALSO BECOME SLIGHTLY WARMER EACH DAY
WITH SLOWLY INCREASING 850 MB TEMPERATURES FROM THE SOUTHERLY
COMPONENT OF THE MID LEVEL FLOW. THE MOST UNSTABLE DAY AT THIS TIME
LOOKS TO BE WEDNESDAY...HOWEVER IT WILL ALSO BE UNSTABLE IN THE
AFTERNOONS AND EVENINGS TODAY AND TUESDAY AS WELL. THUNDERSTORMS ARE
NOT EXPECTED TO BECOME SEVERE...AND MOST WILL BE PULSE TYPE STORMS.
THESE MAY POSSIBLY PRODUCE SMALL HAIL...GUSTY WINDS AND HEAVY RAIN.
HEAVY RAIN ASSOCIATED WITH ANY SLOW MOVING STORMS MAY CAUSE LOCAL
FLOODING OF SMALL STREAMS AND CREEKS...AS WELL AS IN IRRIGATION
DITCHES/CULVERTS AND ROADWAY UNDERPASSES. 88

LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY NIGHT...AS THE UPPER LOW
MOVES OFFSHORE AND INTO THE EASTERN PACIFIC...MOIST SOUTHERLY FLOW
WILL BRING MODERATE RAIN AND A CHANCE FOR AFTERNOON/EVENING
THUNDERSTORMS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. ON FRIDAY...A
WEAK RIDGE SHOULD BUILD OVER THE AREA...ALLOWING FOR SIGNIFICANTLY
DRIER CONDITIONS. THE UPPER LOW THEN ROTATES BACK TOWARDS THE COAST
ON SATURDAY AND SUNDAY...BRINGING ENOUGH INSTABILITY AND MOISTURE
BACK TO THE REGION TO FUEL SCATTERED MOUNTAIN SHOWERS. WITH PARTLY
TO MOSTLY CLOUDY CONDITIONS EXPECTED THROUGH THE WEEK...TEMPERATURES
WILL REMAIN SEASONABLY MILD.  CALDER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  72  52  74  53 /  30  30  30  20
ALW  72  53  74  54 /  30  30  30  20
PSC  77  55  79  56 /  20  20  20  20
YKM  74  53  76  54 /  30  30  20  20
HRI  76  53  78  54 /  30  30  20  20
ELN  73  50  75  51 /  30  30  20  20
RDM  66  44  68  45 /  30  30  30  30
LGD  65  49  66  50 /  40  40  30  30
GCD  67  47  69  48 /  40  40  40  30
DLS  73  53  75  54 /  60  30  30  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&

TI:GYY
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
85

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
515 AM PDT MON MAY 26 2008

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-271200-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
CENTRAL OREGON-LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-
WALLOWA COUNTY-FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-
NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-
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-
EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
515 AM PDT MON MAY 26 2008

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 CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, 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, EASTERN COLUMBIA
     RIVER GORGE OF OREGON, NORTH CENTRAL OREGON, CENTRAL OREGON,
     LOWER COLUMBIA BASIN OF OREGON, GRANDE RONDE VALLEY, WALLOWA
     COUNTY, FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON, NORTHERN
     BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES, JOHN DAY
     BASIN, OCHOCO-JOHN DAY HIGHLANDS

MOIST AND UNSTABLE AIR WILL CONTINUE TO BE PUMPED INTO THE REGION IN
AN EAST TO NORTHEAST MID LEVEL FLOW AROUND A LARGE AND PERSISTENT
UPPER LOW PRESSURE SYSTEM OVER THE SOUTHERN GREAT BASIN. THE
COMBINATION OF ABUNDANT MOISTURE IN THE ATMOSPHERE AND BREAKS IN THE
OVERCAST AT TIMES WILL ALLOW PERIODS OF SUNSHINE WHICH WILL CAUSE
STRONG SURFACE HEATING. AS A RESULT ISOLATED TO SCATTERED AFTERNOON
AND EVENING THUNDERSTORMS. ALTHOUGH SEVERE THUNDERSTORMS ARE NOT
EXPECTED AT THIS TIME...SOME STORMS MAY PRODUCE STRONG GUSTY
WINDS...SMALL HAIL AND HEAVY RAIN. FLASH FLOODING MAY BECOME A
CONCERN IN SMALL STREAMS AND CREEKS AS WELL AS IRRIGATION
DITCHES/CULVERTS AND ROADWAY UNDERPASSES.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THUNDERSTORMS TUESDAY
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN COLUMBIA RIVER
     GORGE OF WASHINGTON, LOWER COLUMBIA BASIN OF WASHINGTON,
     FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON, NORTHWEST BLUE
     MOUNTAINS, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
     CENTRAL OREGON, CENTRAL OREGON, LOWER COLUMBIA BASIN OF
     OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY, FOOTHILLS OF THE
     BLUE MOUNTAINS OF OREGON, NORTHERN BLUE MOUNTAINS OF OREGON,
     SOUTHERN BLUE MOUNTAINS OF OREGON, NORTHERN WHEELER AND
     SOUTHERN GILLIAM COUNTIES, JOHN DAY BASIN, OCHOCO-JOHN DAY
     HIGHLANDS

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

MUCH OF THE SAME WEATHER WILL CONTINUE THROUGH AT LEAST MID WEEK
WITH MOIST AND UNSTABLE AIR CONTINUING TO BE PUMPED INTO THE REGION
AROUND AN UPPER LOW PRESSURE SYSTEM. THE COMBINATION OF MOISTURE
LADEN AIR AND BREAKS IN THE OVERCAST AT TIMES WILL ALLOW PERIODS OF
SUNSHINE WHICH WILL CAUSE STRONG SURFACE HEATING. AS A RESULT
ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL
DEVELOP EACH DAY. ALTHOUGH SEVERE THUNDERSTORMS ARE NOT EXPECTED AT
THIS TIME...SOME STORMS MAY PRODUCE STRONG GUSTY WINDS...SMALL HAIL
AND HEAVY RAIN. FLASH FLOODING MAY BECOME A CONCERN IN SMALL STREAMS
AND CREEKS AS WELL AS IRRIGATION DITCHES/CULVERTS AND ROADWAY
UNDERPASSES. AT THIS TIME THE MOST UNSTABLE DAY WITH THE GREATEST
POTENTIAL FOR THUNDERSTORMS LOOKS TO BE ON WEDNESDAY.

CONDITIONS WILL BECOME DRIER AND MORE STABLE LATE IN THE WEEK BEFORE
THE PATTERN BECOMES MOIST AND UNSTABLE AGAIN DURING THE WEEKEND.

.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...EXCEPT THE H IN
CURRENTHAZARDS.