Wildfire in Oregon, June 1 to 3, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1045 PM PDT THU MAY 31 2007

UPDATED AVIATION

.SHORT TERM...FOR THIS EVENING...SOME ISOLATED THUNDERSTORM ACTIVITY
HAS DEVELOPED OVER SOUTHEAST DESCHUTES COUNTY THIS EVENING. RADAR
AND SATELLITE DATA SHOWS THAT THE INTENSITY OF THE STORMS ARE
BEGINNING TO DECREASE. THEY ARE EXPECTED TO FURTHER DECREASE OVER
THE NEXT COUPLE OF HOURS AND COME TO AN END BY 10 PM WITH CLEARING
SKIES. REST OF THE FORECAST AREA IS UNDER CLEAR SKIES AND REMAIN SO
OVERNIGHT. MADE MINOR ADJUSTMENT OT THE ZONES REMOVING THUNDERSTORMS
FROM THE FORECAST FOR NORTH CENTRAL OREGON THIS EVENING...OTHERWISE
FORECAST IS ON TRACK.

&&

AVIATION...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE NEXT
24 HOURS. ISOLATED THUNDERSTORMS ARE POSSIBLE AGAIN OVER SOUTH
CENTRAL OREGON FRIDAY AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 200 PM PDT THU MAY 31 2007/

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...SUMMER HAS ARRIVED
HERE IN THE PACIFIC NORTHWEST...AT LEAST EAST OF THE CASCADES.
STRONG WARMING TREND CURRENTLY IN PROGRESS AS AN UPPER RIDGE ALOFT
BUILDS OVER THE REGION. MAIN CONCERN NEXT COUPLE DAYS WILL BE HOW
HOT IT WILL GET AND IF/WHERE AFTERNOON AND EVENING THUNDERSTORMS
WILL DEVELOP. ANOTHER CONCERN IS IF THESE STORMS WILL PRODUCE DRY
LIGHTNING WITH HIGH BASES DUE TO SUCH A WARM AND DRY AIR MASS AT THE
SURFACE. UPPER RIDGE AXIS IS EXPECTED TO MOVE ACROSS THE CWA DURING
THE DAY FRIDAY. WITH IT WILL BE A THERMALLY INDUCED LOW PRESSURE
AREA AT THE SURFACE WHICH WILL MARK WHERE AND WHEN THE HOTTEST AIR
WILL BE IN THIS KIND OF WEATHER PATTERNS. SURFACE PRESSURE GRADIENTS
ON FRIDAY WILL STILL BE FROM THE NORTH TO NORTHEAST. THE UPPER RIDGE
AND SURFACE THERMAL LOW APPEARS THAT THEY WILL STALL OVER EASTERN
OREGON AND SOUTHEAST WASHINGTON ON SATURDAY AND SUNDAY...MAKING
THESE TWO DAYS THE WARMEST DAYS OF THIS ONCOMING HOT SPELL. MODEL
FORECAST 850 MB TEMPERATURES ARE EXPECTED TO REACH THE UPPER 20S TO
NEAR 30 C FROM THE GFS AND MID TO UPPER 20S C BY THE NAM12 MODEL. IF
THESE 850 MB TEMPERATURES VERIFY RECORD HIGH TEMPERATURES WILL
LIKELY BE SET IN MANY LOCATIONS...SOME OF WHICH WILL EXCEED 100
DEGREES F. ISOLATED THUNDERSTORMS WILL BEGIN TO DEVELOP OVER THE
EXTREME SOUTHWEST PORTIONS OF THE FORECAST AREA LATE THIS AFTERNOON
AND THIS EVENING. THEY ARE EXPECTED TO INCREASE IN AREAL COVERAGE
DURING THE PERIOD FRIDAY THROUGH SUNDAY. AT THIS TIME THE
THUNDERSTORMS DO NOT APPEAR THAT THEY WILL BECOME SEVERE...HOWEVER
THE SITUATION WILL NEED TO BE MONITORED FOR THE POTENTIAL. 88

LONG TERM...GFS DEPICTS THE UPPER RIDGE STARTING TO MOVE EAST
SUNDAY WHICH WILL ALLOW COOLER MARINE AIR TO FILTER OVER THE CWA
MONDAY. HOWEVER...THINGS MAY PROGRESS A LITTLE SLOWER SINCE GFS IS
NOTORIOUS FOR MOVING THE RIDGE TOO QUICKLY EASTWARD. AS A RESULT...
THE COOL DOWN WILL TAKE PLACE OVER A PERIOD MONDAY THROUGH TUESDAY.
A TIGHT PRESSURE GRADIENT BEHIND THE MARINE PUSH WILL CAUSE BREEZY
TO WINDY CONDITIONS ACROSS THE CWA. A GENERAL TROUGHY WEATHER
PATTERN WILL THEN PERSIST THROUGH THE REST OF THE EXTENDED PERIOD
RESULTING IN A SLIGHT CHANCE OF MOUNTAIN SHOWERS AND TEMPERATURES
BACK TO NEAR NORMAL. EARLE

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  56  93  57  95 /   0  10   0   0
ALW  59  93  62  96 /   0   0   0   0
PSC  54  96  56  99 /   0   0   0   0
YKM  57  93  57  95 /  10  10   0   0
HRI  53  95  56  98 /   0   0   0   0
ELN  54  90  56  92 /  10  10   0   0
RDM  47  92  50  95 /  10  20  20  20
LGD  49  86  51  88 /   0  10  10  10
GCD  51  91  50  94 /   0  20  20  20
DLS  61  94  60  97 /   0   0   0   0

&&

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

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

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1043 PM PDT THU MAY 31 2007

UPDATED TO REMOVE THUNDERSTORMS FROM DAY ONE

ORZ041-WAZ024-501-502-026>030-ORZ042>044-049-050-501>506-011215-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-
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-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-
1043 PM PDT THU MAY 31 2007

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

.DAY ONE...TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

THUNDERSTORMS HAVE DISSIPATED ACROSS SOUTHEASTERN DESCHUTES COUNTY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS FRIDAY
     NORTH CENTRAL OREGON, CENTRAL OREGON, WALLOWA COUNTY, SOUTHERN
     BLUE MOUNTAINS OF OREGON, NORTHERN WHEELER AND SOUTHERN
     GILLIAM COUNTIES, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS

THUNDERSTORMS SATURDAY
     NORTH CENTRAL OREGON, CENTRAL OREGON, 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

THUNDERSTORMS SUNDAY
     NORTH CENTRAL OREGON, CENTRAL OREGON, WALLOWA COUNTY, NORTHERN
     BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     OCHOCO-JOHN DAY HIGHLANDS

THUNDERSTORMS MONDAY
     WALLOWA COUNTY, NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN
     BLUE MOUNTAINS OF OREGON

THUNDERSTORMS TUESDAY
     WALLOWA COUNTY

A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS WILL SPREAD
FROM CENTRAL OREGON TO NORTHEAST OREGON MOUNTAINS FRIDAY THROUGH
SUNDAY AS INSTABILITY INCREASES WITH INCREASED DAYTIME HEATING.

A WEATHER SYSTEM FROM THE PACIFIC WILL MOVE OVER THE REGION MONDAY
RESULTING IN THE SLIGHT CHANCE THUNDERSTORM THREAT AREA SHIFTING
EASTWARD BOTH MONDAY AND TUESDAY.

.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/PENDLETON/CURRENTHAZARDS/HWO.HTML

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE...EXCEPT THE H IN
CURRENTHAZARDS.