Excessive Heat in Oregon, June 29 to 30, 2008

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
1050 AM PDT SUN JUN 29 2008

UPDATED AVIATION DISCUSSION

.UPDATE...CLEAR SKIES AND LIGHT WINDS OVER MOST OF THE AREA. A FEW
CUMULUS BUILDUPS ARE SPREADING NORTH IN CENTRAL OREGON AND ALONG THE
OREGON CASCADES. THESE WILL DEVELOP INTO THUNDERSTORMS LATER TODAY
AS HEATING INCREASES ENOUGH TO BREAK CAP IN CENTRAL OREGON. EASTERN
WASHINGTON AND OREGON WILL BE HOT AGAIN TODAY FROM SUBSIDENCE FROM
AN UPPER LEVEL RIDGE ALONG THE BORDER WITH IDAHO. A HEAT ADVISORY
HAS BEEN ISSUED FOR THE LOWER COLUMBIA BASIN AND ADJACENT VALLEYS
THROUGH MONDAY. SEE LATEST NPWPDT FOR DETAILS. FIRE WEATHER WATCHES
AND RED FLAG WARNINGS HAVE BEEN ISSUED FOR VARIOUS AREAS DUE TO
LIGHTNING THREAT FROM THUNDERSTORMS. SEE LATEST RFWPDT FOR
DETAILS.  COONFIELD

&&

AVIATION...18Z TAFS...VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24
HOURS. THUNDERSTORMS ARE EXPECTED TO DEVELOP IN CENTRAL OREGON THIS
AFTERNOON...SO KRDM WILL HAVE A THREAT OF THUNDERSTORMS FROM 21Z
SUNDAY TO 06Z MONDAY. THESE THUNDERSTORMS WILL MOVE NORTHWARD INTO
NORTH CENTRAL OREGON AND SOUTH CENTRAL WASHINGTON BY LATE THIS
AFTERNOON AND CONTINUING THROUGH THIS EVENING. KDLS WILL HAVE A
THREAT OF THUNDERSTORMS FROM 00Z TO 06Z MONDAY.

&&

.PREV DISCUSSION... /ISSUED 650 AM PDT SUN JUN 29 2008/

SHORT TERM...TODAY THROUGH MONDAY...THUNDERSTORMS OVER WESTERN
DESCHUTES COUNTY HAVE MOVED OFF TO THE WEST AND WEAKENED. SOME
CUMULUS CLOUDS REMAIN OVER SOUTHWESTERN OREGON AND ARE MOVING NORTH
TO NORTHWEST. THERE IS STILL A CHANCE OF A STRIKE OR TWO FROM THESE
CELLS...THOUGH THE MAJORITY OF THE ACTIVITY HAS DECREASED OVERALL
THIS MORNING. THE REST OF THE REGION WILL SEE MOSTLY CLEAR TO CLEAR
SKIES THIS MORNING UNDER HIGH PRESSURE. THIS RIDGE OF HIGH PRESSURE
WILL CONTINUE TO STRENGTHEN OFF TO THE EAST...WITH THE AREA UNDER A
SOUTHERLY FLOW. SUBSIDENCE FROM THE RIDGE WILL ALLOW TEMPERATURES TO
CONTINUE TO WARM...WITH MANY AREAS EXCEEDING 100 DEGREES. THE
HOTTEST AREAS INCLUDE THE COLUMBIA BASIN...YAKIMA AND KITTITAS
VALLEY...THE COLUMBIA RIVER GORGE...JOHN DAY VALLEY AND THE
FOOTHILLS OF THE BLUE MOUNTAINS. THESE AREAS ARE UNDER A HEAT
ADVISORY THAT WILL CONTINUE INTO MONDAY. CENTRAL OREGON COULD ALSO
SEE TEMPERATURES APPROACH 100 DEGREES...THOUGH CLOUD COVER FROM
CONVECTION MAY KEEP HIGH TEMPERATURES SIMILAR TO A FEW DEGREES
WARMER THAN YESTERDAY.

UNSTABLE CONDITIONS ALONG WITH MOISTURE FROM A LOW PRESSURE SYSTEM
OFF THE CALIFORNIA COAST WILL AGAIN INITIATE CONVECTION ACROSS
NORTHERN CALIFORNIA AND SOUTHERN OREGON. A DISTURBANCE IN THIS FLOW
WILL ALLOW CONVECTION TO DEVELOP IN CENTRAL OREGON THIS AFTERNOON
AND THEN SPREAD NORTHWARD ALONG THE CASCADES AS WELL AS INTO THE
BLUE MOUNTAINS. PRECIPITABLE WATERS START OUT LOW BUT WILL INCREASE
OVERNIGHT WITH MODEL SOUNDINGS IN CENTRAL OREGON...THE GRANDE RONDE
VALLEY AND THE COLUMBIA RIVER GORGE SHOWING AROUND 1.00 INCH BY THE
EVENING HOURS. THEREFORE BELIEVE THAT LIGHT RAIN WILL BE POSSIBLE
WITH STORMS AT THE START...AND THEN MODERATE TO HEAVY RAIN POSSIBLE
WITH THE STORMS BY EVENING. WHILE DAYTIME HEATING WILL HELP
CONTRIBUTE TO DESTABILIZING THE ATMOSPHERE...THE DISTURBANCE MAY
HELP KEEP STORMS GOING PAST MIDNIGHT. ON MONDAY...DAYTIME HEATING
AND ANOTHER DISTURBANCE FROM THE LOW PRESSURE SYSTEM WILL BRING
ANOTHER CHANCE OF THUNDERSTORMS. THIS DISTURBANCE WILL MOVE ACROSS
EASTERN OREGON AND WASHINGTON...PROVIDING LIFT AND MOISTURE IN THE
UNSTABLE AIR ACROSS THE ENTIRE REGION. THEREFORE...THERE IS A CHANCE
OF THUNDERSTORMS ACROSS THE ENTIRE AREA BY MONDAY AFTERNOON.

WITH THE THREAT OF SCATTERED THUNDERSTORMS IN CENTRAL OREGON THIS
AFTERNOON THROUGH MONDAY EVENING...A FIRE WEATHER WATCH HAS BEEN
ISSUED. DMH

LONG TERM...MONDAY NIGHT THROUGH SATURDAY...A SOUTHERLY FLOW WILL
CONTINUE TO BRING MOISTURE AND INSTABILITY INTO THE FORECAST AREA ON
MONDAY NIGHT THROUGH WEDNESDAY FOR A CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS. AN UPPER LEVEL TROUGH NEAR 135W ON
WEDNESDAY WILL PUSH A WEAK COLD FRONT TOWARD THE COAST AND BRING IT
INLAND WEDNESDAY AND THEN INTO THE FORECAST AREA ON THURSDAY FOR A
CHANCE OF THUNDERSTORMS IN THE HIGHER ELEVATIONS OF CENTRAL AND
NORTHEAST OREGON. THE UPPER LEVEL TROUGH WILL THEN MOVE ACROSS THE
REGION ON FRIDAY FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. SATURDAY
LOOKS TO BE DRY AS HIGH PRESSURE MOVE OVER THE INTERIOR PACIFIC
NORTHWEST.  POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT 102  67 100  65 /  10  10  30  40
ALW 102  70 100  70 /  10  10  30  40
PSC 106  66 102  68 /  10  10  20  40
YKM 103  69 100  64 /  10  10  20  20
HRI 106  65 100  68 /  10  10  20  40
ELN 103  66  99  65 /  10  10  20  20
RDM 100  54  94  52 /  30  30  30  20
LGD  99  60  98  60 /  10  20  30  20
GCD 101  61  99  60 /  20  30  30  20
DLS 104  70  99  66 /  20  30  20  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM 8 PM PDT THIS EVENING THROUGH TUESDAY
     MORNING FOR ORZ609-631.

     HEAT ADVISORY UNTIL 8 PM PDT MONDAY FOR ORZ501.

     RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 9 AM PDT TUESDAY
     FOR ORZ610-630.

     HEAT ADVISORY UNTIL 8 PM PDT MONDAY FOR ORZ041-044-505.

WA...FIRE WEATHER WATCH FROM 8 PM PDT THIS EVENING THROUGH TUESDAY
     MORNING FOR WAZ609-631.

     HEAT ADVISORY UNTIL 8 PM PDT MONDAY FOR WAZ029-502.

     HEAT ADVISORY UNTIL 8 PM PDT MONDAY FOR WAZ024-026>028.

&&

TI:YYG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
76/91/91

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
920 AM PDT SUN JUN 29 2008

UPDATED FOR FIRE WEATHER WATCHES AND WARNINGS

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-301230-
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-
920 AM PDT SUN JUN 29 2008

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

.DAY ONE...TODAY AND TONIGHT

FIRE WEATHER WARNING
     NORTH CENTRAL OREGON, CENTRAL OREGON, OCHOCO-JOHN DAY
     HIGHLANDS

FIRE WEATHER WATCH
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN
     COLUMBIA RIVER GORGE, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN, FOOTHILLS OF THE BLUE MOUNTAINS

THUNDERSTORMS
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, NORTHWEST
     BLUE MOUNTAINS, GRANDE RONDE VALLEY, WALLOWA COUNTY, NORTHERN
     BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON

EXCESSIVE HEAT
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN
     COLUMBIA RIVER GORGE, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN, FOOTHILLS OF THE BLUE MOUNTAINS, NORTHERN
     WHEELER AND SOUTHERN GILLIAM COUNTIES, JOHN DAY BASIN

A RIDGE OF HIGH PRESSURE WILL BRING HOT AND DRY CONDITIONS
TODAY...AS THE REGION SEES THE THE HOTTEST TEMPERATURES SO FAR THIS
YEAR. MANY LOCATIONS WILL REACH OR EXCEED 100 DEGREES. PLEASE REFER
TO PRODUCT PDXNPWPDT FOR DETAILS ON THE HEAT ADVISORY.

A WEATHER DISTURBANCE ASSOCIATED WITH A LOW PRESSURE SYSTEM OFF THE
CALIFORNIA COAST WILL MOVE NORTHWARD INTO THE REGION THIS AFTERNOON.
THIS WILL PROVIDE ENOUGH INSTABILITY AND MOISTURE TO DEVELOP
THUNDERSTORMS IN CENTRAL OREGON AND SPREAD NORTHWARD ALONG THE
CASCADES AS WELL AS NORTHEAST OVER THE BLUE MOUNTAINS BY EVENING.
WITH THE GRASSES AND SHRUBS IN THE LOWER ELEVATIONS ACROSS CENTRAL
OREGON BEING DRY...SCATTERED THUNDERSTORMS FROM THIS AFTERNOON
THROUGH MONDAY WILL THREATEN THESE AREAS WITH LIGHTNING-CAUSED
FIRES. A FIRE WEATHER WARNING IS IN EFFECT THIS AFTERNOON THROUGH
MONDAY EVENING FOR NORTH CENTRAL OREGON, CENTRAL OREGON, AND THE
OCHOCO-JOHN DAY HIGHLANDS. ISOLATED TO SCATTERED THUNDERSTORMS WILL
SPREAD NORTH AND EAST TONIGHT INTO THE COLUMBIA RIVER GORGE AND
WESTERN PART OF THE LOWER COLUMBIA BASIN...AND SPREAD FARTHER EAST
ON MONDAY. A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THESE AREAS.
PLEASE REFER TO FIRE WEATHER PRODUCT PDXRFWPDT FOR MORE DETAILS AND
CONTACT YOUR LOCAL FOREST OR LAND MANAGEMENT AGENCY FOR CURRENT FIRE
DANGER CONDITIONS IN YOUR AREA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

FIRE WEATHER WARNING
     NORTH CENTRAL OREGON, CENTRAL OREGON, OCHOCO-JOHN DAY
     HIGHLANDS

FIRE WEATHER WATCH
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN
     COLUMBIA RIVER GORGE, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN, FOOTHILLS OF THE BLUE MOUNTAINS

STRONG THUNDERSTORMS MONDAY
     NORTHWEST BLUE MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL
     OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY, NORTHERN BLUE
     MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES, OCHOCO-JOHN
     DAY HIGHLANDS

THUNDERSTORMS MONDAY
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON

EXCESSIVE HEAT MONDAY
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN
     COLUMBIA RIVER GORGE, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
     COLUMBIA BASIN, FOOTHILLS OF THE BLUE MOUNTAINS, NORTHERN
     WHEELER AND SOUTHERN GILLIAM COUNTIES, JOHN DAY BASIN

THUNDERSTORMS TUESDAY THROUGH THURSDAY
     NORTHWEST BLUE MOUNTAINS, CENTRAL OREGON, LOWER COLUMBIA BASIN
     OF OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY, NORTHERN BLUE
     MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES, JOHN DAY
     BASIN, OCHOCO-JOHN DAY HIGHLANDS

THE RIDGE OF HIGH PRESSURE WILL KEEP CONDITIONS HOT AND DRY THROUGH
MONDAY. THE COLUMBIA BASIN AND SURROUNDING VALLEYS WILL CONTINUE TO
SEE HIGH TEMPERATURES EXCEEDING 100 DEGREES. PLEASE REFER TO
PDXNPWPDT FOR MORE DETAILS ON THE HEAT ADVISORY.

THE LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST WILL LIFT NORTHWARD
AND SEND ANOTHER...STRONGER DISTURBANCE ACROSS THE REGION MONDAY
AFTERNOON. WITH UNSTABLE CONDITIONS ACROSS THE AREA...THUNDERSTORMS
ARE POSSIBLE ACROSS THE REGION. A MARINE PUSH LATE ON MONDAY WILL
ADD FURTHER LIFT FOR STRONGER STORMS TO DEVELOP ACROSS THE MOUNTAINS
OF NORTHEAST OREGON AND SOUTHEAST WASHINGTON. THESE STORMS MAY BE
CAPABLE OF STRONG GUSTY WINDS AND LARGE HAIL. SEE LATEST PDXRFWPDT
FOR DETAILS ON FIRE WEATHER WATCHES AND WARNINGS DUE TO LIGHTNING ON
MONDAY.

WEATHER DISTURBANCES WILL CONTINUE TO BRING UNSTABLE CONDITIONS TO
THE MOUNTAINS OF NORTHEAST OREGON AND SOUTHEAST WASHINGTON...WITH A
CHANCE OF THUNDERSTORMS EACH AFTERNOON THROUGH THE END OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TODAY AND TOMORROW FOR
THUNDERSTORMS.

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.