Wildfire in Oregon, August 21 to 25, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1032 PM PDT SAT AUG 20 2005

UPDATED FOR AVIATION DISCUSSION

&&

.AVIATION...VFR CONDITIONS CAN BE EXPECTED FOR THE NEXT 24 HOURS AT
ALL TAF LOCATIONS AND ON ALL TWEB ROUTES. A FEW ISOLATED
THUNDERSTORMS ARE POSSIBLE DURING SUNDAY AFTERNOON AND EVENING OVER
THE MOUNTAINS OF CENTRAL AND NORTHEAST OREGON. OTHERWISE...ONLY FEW
TO SCT CUMULUS AND CIRRUS CLOUDS WILL BE PRESENT. SURFACE WINDS WILL
BE UNDER 15 KNOTS AT ALL TAF LOCATIONS. PERRY

&&

.PREV DISCUSSION... (ISSUED 905 PM PDT SAT AUG 20 2005)

SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...NO UPDATE PLANNED. A
VERY WELL DEFINED AND STRONG RIDGE OF HIGH PRESSURE REMAINS IN PLACE
OVER THE REGION LEADING TO CLEAR SKIES AND VERY WARM TEMPERATURES
THIS EVENING. TOMORROW WILL SEE A WEAK DISTURBANCE...NOW BARELY
VISIBLE ON WATER VAPOR IMAGERY OFF THE NORTHERN CALIFORNIA
COAST...MAKE ITS WAY INTO THE AREA TOMORROW. IT WILL REACH THE
DESCHUTES PLATEAU AROUND NOON AND PROGRESS THROUGH THE MOUNTAINS OF
CENTRAL AND NORTHEAST OREGON THROUGH TOMORROW EVENING. WITH THE
ATMOSPHERE ALREADY UNSTABLE...THIS DISTURBANCE WILL ADD EVEN MORE
LIFT AND LEAD TO ISOLATED THUNDERSTORMS IN THE MOUNTAINS. THERE IS
LITTLE MOISTURE TO WORK WITH BUT EXPECT A FEW THUNDERSTORMS WILL
FIRE UP AND WILL AT LEAST INITIALLY BE DRY BEFORE THE LOWER LEVELS
OF THE ATMOSPHERE BECOME MORE MOIST. MONDAY WILL SEE A FRONTAL
PASSAGE THAT WILL LEAD TO A FEW SHOWERS AND THUNDERSTORMS OVER THE
MOUNTAINS OF CENTRAL AND EASTERN OREGON AGAIN...BUT ONCE AGAIN
LIMITED MOISTURE WILL KEEP THE NUMBER OF STORMS AND SHOWERS DOWN.
THE FRONT WILL CAUSE BREEZY CONDITIONS IN THE COLUMBIA GORGE AND
KITTITAS VALLEY AND BRING COOLER MARINE AIR INTO THE REGION AND COOL
TEMPERATURES DOWN 5-7 DEGREES MONDAY. PERRY

PREV DISCUSSION... (ISSUED 303 PM PDT SAT AUG 20 2005)

LONG TERM...TUESDAY THROUGH SATURDAY...AN UPPER LEVEL LOW PRESSURE
TROUGH WILL BE OVER EASTERN WASHINGTON AND NORTHEAST OREGON ON
TUESDAY...WHICH WILL KEEP A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS OF NORTHEAST OREGON AND SOUTHEAST
WASHINGTON ON TUESDAY. THEN HIGH PRESSURE WILL BUILD OVER THE
PACIFIC NORTHWEST ON WEDNESDAY THROUGH SATURDAY FOR DRY CONDITIONS.
POLAN

FIRE WEATHER...HOT AND DRY CONDITIONS WILL PERSIST INTO SUNDAY
ACROSS THE AREA.  THE APPROACHING WEATHER DISTURBANCE AND ASSOCIATED
THUNDERSTORM DEVELOPMENT WILL BE THE MAIN FIRE WEATHER CONCERN OVER
THE NEXT 36 HOURS.  MOISTURE PROFILES OF THE MID AND UPPER-LEVELS
ARE NOT VERY IMPRESSIVE WITH THE APPROACHING SYSTEM SO SOME STORMS
MAY BEGIN VIRTUALLY DRY OF PRECIPITATION.  STORMS WILL BECOME MORE
MOIST OVERTIME...BUT WILL HAVE THE POTENTIAL OF GENERATING GUSTY
WINDS.  FUELS REMAIN EXTREMELY DRY OVER THE AREA AND ANY LIGHTNING
PRODUCED SUNDAY AFTERNOON AND EVENING WILL HAVE THE POTENTIAL TO
CREATE FIRE STARTS.  WILL ISSUE A FIRE WEATHER WATCH HIGHLIGHTING
THE LIGHTNING POTENTIAL AFTER AN EXTENDED DRY PERIOD SLATED FOR
SUNDAY AND SUNDAY NIGHT.  FIRE WEATHER ZONES INCLUDED IN THE WATCH
ARE 611/630/632/633/634/635/638.  A MARINE PUSH MONDAY WILL HELP TO
MOISTEN THE AIRMASS ACROSS THE AREA. 96

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM 6 AM SUNDAY TO MIDNIGHT MONDAY FOR
     ORZ042-ORZ043-ORZ047-ORZ048.

     FIRE WEATHER WATCH FROM 10 AM SUNDAY TO MIDNIGHT MONDAY FOR
     ORZ045-ORZ046-ORZ049-ORZ050.

WA...FIRE WEATHER WATCH FROM 10 AM SUNDAY TO MIDNIGHT MONDAY FOR
     WAZ030.

&&

TI:GGG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
83/83/83

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
325 PM PDT SAT AUG 20 2005

WAZ024>030-ORZ041>050-211215-
EAST SLOPES OF THE SOUTHERN CASCADES-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-
FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-BLUE MOUNTAINS-
JOHN DAY BASIN-OCHOCO-JOHN DAY HIGHLANDS-GRANDE RONDE VALLEY-
WALLOWA COUNTY-
325 PM PDT SAT AUG 20 2005

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

UPDATED TO ADD MENTION OF FIRE WEATHER WATCH.

.DAY ONE...TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

HIGH PRESSURE WILL KEEP MOSTLY CLEAR SKIES AND DRY CONDITIONS IN THE
FORECAST OVERNIGHT.

.DAYS TWO THROUGH SEVEN...

FIRE WEATHER WATCH SUNDAY
     NORTHWEST BLUE MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL OREGON,
     BLUE MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS,
     GRANDE RONDE VALLEY, WALLOWA COUNTY

     CONTACT YOUR LOCAL FOREST OR LAND MANAGEMENT AGENCY FOR
     CURRENT FIRE DANGER CONDITIONS IN YOUR AREA.

THUNDERSTORMS SUNDAY
     NORTHWEST BLUE MOUNTAINS, CENTRAL OREGON, BLUE MOUNTAINS, JOHN
     DAY BASIN, GRANDE RONDE VALLEY, WALLOWA COUNTY, OCHOCO-JOHN
     DAY HIGHLANDS

A WEATHER DISTURBANCE...COMBINED WITH ATMOSPHERIC INSTABILITY AND
LIMITED MID AND UPPER-LEVEL MOISTURE...WILL GENERATE ISOLATED
THUNDERSTORMS SUNDAY.  THE DISTURBANCE WILL APPROACH CENTRAL OREGON
BY EARLY MORNING AND CONVECTION MAY INITIATE BEFORE SUNRISE THERE.
AREAS TO THE EAST AND NORTH WILL SEE THE BEST CONVECTIVE POTENTIAL
BY MID TO LATE AFTERNOON AND ON INTO THE EVENING.  THE ATMOSPHERE
WILL MOISTEN WITH TIME...AND AT THE ONSET OF CONVECTION SOME STORMS
WILL HAVE THE ABILITY TO PRODUCE LITTLE TO NO PRECIPITATION.  FOR
DETAILS ON THE FIRE WEATHER WATCH SEE THE LATEST PDXRFWPDT OR
WWUS86 KPDT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED SUNDAY FOR THUNDERSTORM ACTIVITY
OVER THE CENTRAL AND EASTERN MOUNTAINS.

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

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

WEATHER.GOV/PENDLETON

AND SELECT GRAPHICAL HAZARDS.