Wildfire in Washington, August 20 to 25, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
847 PM PDT THU AUG 20 2009

.SHORT TERM...A DISTURBANCE OVER WESTERN WASHINGTON IS MOVING
NORTH-NORTHEAST ON THE WEST SIDE THE UPPER RIDGE NOW SHIFTING ACROSS
WESTERN IDAHO. THERE IS A WEAK TROUGH TRAILING SOUTH FROM THIS
DISTURBANCE ALONG THE CASCADE CREST. MEANWHILE A SECONDARY...WEAKER
DISTURBANCE IS ATTACHED TO THE SOUTH END OF THE TROUGH...AND IS OVER
SOUTHWEST OREGON. ALL THESE FEATURES SHOULD CONTINUE NORTH-NORTHEAST
THROUGH THE NIGHT. THIS STRING OF DISTURBANCES HELPED TO INCREASE
ELEVATED INSTABILITY ENOUGH TO PRODUCE ISOLATED LIGHT SHOWERS OVER
NORTHERN GRANT COUNTY AND EASTERN JEFFERSON COUNTY EARLIER THIS
EVENING. THESE SHOWERS HAVE PROMPTED EARLIER ADJUSTMENTS TO THE
FORECAST PACKAGE. EXPECT THE WEAK ELEVATED CONVECTION OVER CENTRAL
OREGON TO DISSIPATE BY MIDNIGHT AS THE ENERGY DRIVING IT SHIFTS
NORTH. MEANWHILE FOCUS OF ELEVATED CONVECTION LATE THIS EVENING INTO
EARLY FRIDAY MORNING LOOKS TO SHIFT INTO SOUTH-CENTRAL WASHINGTON.
WILL WATCH HOW THIS DEVELOPS AND MAY HAVE TO MAKE FURTHER FORECAST
ADJUSTMENTS FOR SOUTH-CENTRAL WASHINGTON. TEMPS AT MOST LOCATIONS
WITHIN THE HEAT ADVISORY HAD FALLEN BELOW 100 DEGREES BY 730 PM WITH
THE LINGERING HOT TEMPS DONE BY 800 PM...THUS WAS ABLE TO CANCEL THE
ADVISORY PRIOR TO 800 PM. 90

.LONG TERM...PREVIOUS DISCUSSION...A BROAD UPPER RIDGE WILL REMAIN
STATIONARY ACROSS THE CENTRAL U.S. WHILE A BROAD TROUGH WILL REMAIN
OFF THE EASTERN PACIFIC.  THIS WILL LEAVE THE PACIFIC NW UNDER A
W-SW FLOW ALOFT.  ON SUNDAY NIGHT THROUGH TUESDAY...THE FORECAST
AREA IS UNDER AN ANTICYCLONIC FLOW ASSOCIATED WITH THE UPPER RIDGE
TO THE EAST AND THERE DOES NOT APPEAR TO BE ANY WAVES MOVING ACROSS
THE AREA.  WILL KEEP A DRY FORECAST FOR THIS TIME PERIOD.  WILL ALSO
KEEP TUESDAY NIGHT DRY...ALTHOUGH THERE IS A WAVE MOVING ACROSS
NORTHERN WASHINGTON THAT MAY CLIP THE EAST SLOPES OF THE CENTRAL WA
CASCADES. ON WEDNESDAY AND THURSDAY...THE UPPER FLOW IS MAINLY FROM
THE SOUTH WITH MORE CLOUD COVER EXPECTED AND A BETTER CHANCE FOR
PRECIPITATION.  WILL KEEP THE SLIGHT CHANCE OF SHOWERS/TSTMS IN THE
HIGHER TERRAIN OF EASTERN OREGON AS THERE ARE SOME MODEL DIFFERENCES
ON THE LOCATION OF A SHORTWAVE TROUGH MOVING ACROSS THE AREA.

&&

.AVIATION...PREVIOUS DISCUSSION...00Z TAFS.  CLEAR SKIES OR THIN
HIGH CIRRUS WILL REMAIN OVER THE REGION THROUGH THIS EVENING. THERE
WILL BE SCT-BKN MID LEVEL CLOUDS WITH BASES AROUND 150 AGL FROM
03Z-15Z AS A WEAK WAVE MOVES ACROSS WASHINGTON AND NORTHERN OREGON.
WINDS 15-22 KNOTS WILL CONTINUE AT KDLS THROUGH THIS EVENING THEN
GRADUALLY DECREASE OVERNIGHT.  ALL OTHER TAF SITES WILL SEE WINDS
LESS THAN 15 KNOTS.

&&

.FIRE WEATHER...ONSET OF A WEAK MARINE PUSH HAS BROUGHT INCREASED
WESTERLY WINDS THROUGH THE COLUMBIA GORGE AND INTO THE LOWER
COLUMBIA BASIN WEST OF ARLINGTON. HUMIDITIES ARE NOW RISING THROUGH
THE GORGE AND IN THE CASCADES JUST TO THE NORTH AND SOUTH OF THE
GORGE. AS SUCH...SHOULD BE ABLE TO LOWER THE RED FLAG FOR FIRE ZONE
609 BY 10 PM. CONTINUATION OF THE MARINE PUSH ON FRIDAY WILL SPREAD
MORE WIND ACROSS THE REST OF THE COLUMBIA BASIN WITH THE MAIN
CONCERN OF WIND AND LOW HUMIDITIES OCCURRING EAST OF ARLINGTON. THE
FIRE WEATHER WATCH FOR ZONE 675 WILL BE REASSESSED FRIDAY MORNING AS
TO WHETHER IT NEEDS TO DROPPED OR UPGRADED.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  92  60  86 /   0   0   0  10
ALW  69  93  63  87 /   0   0   0  10
PSC  65  96  60  89 /   0   0   0   0
YKM  62  90  57  87 /   0   0   0   0
HRI  63  94  60  89 /   0   0   0   0
ELN  63  87  57  85 /   0   0   0   0
RDM  53  90  48  86 /   0  10  10  10
LGD  59  92  58  87 /  10  10  10  10
GCD  60  93  56  88 /  20  20  20  10
DLS  63  86  60  83 /   0  10  10   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 10 PM PDT FRIDAY FOR ORZ631.

     RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR ORZ609.

WA...RED FLAG WARNING UNTIL 10 PM PDT FRIDAY FOR WAZ631.

     RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR WAZ609.

     FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING
     FOR WAZ675.

&&

THREAT INDEX
FRIDAY : GREEN
SATURDAY : YELLOW
SUNDAY : YELLOW

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

90/85/90

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
953 PM PDT THU AUG 20 2009

UPDATED FOR THUNDERSTORMS AND END OF RED FLAG WARNING IN FIRE
ZONE 609

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-211430-
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-
953 PM PDT THU AUG 20 2009

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

.DAY ONE...TONIGHT

RED FLAG WARNING
     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, EASTERN COLUMBIA RIVER GORGE OF OREGON, NORTH
     CENTRAL OREGON, LOWER COLUMBIA BASIN OF OREGON, FOOTHILLS OF
     THE BLUE MOUNTAINS OF OREGON, NORTHERN WHEELER AND SOUTHERN
     GILLIAM COUNTIES

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

THUNDERSTORMS
     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

WINDS AND RELATIVE HUMIDITIES HAVE INCREASED NEAR THE CASCADES AND
IN THE COLUMBIA RIVER GORGE. THESE WINDS WILL SPREAD INTO THE
EASTERN PART OF THE LOWER COLUMBIA BASIN THIS EVENING. THE MARINE
AIR WILL NOT REACH MOST OF THE LOWER COLUMBIA BASIN (FWZ 631) UNTIL
LATE FRIDAY. A RED FLAG WARNING HAS BEEN ISSUED FOR FIRE WEATHER
ZONE 631 (LOWER COLUMBIA BASIN OF WASHINGTON AND OREGON). THE RED
FLAG WARNING FOR FOR THE LOWER COLUMBIA BASIN WILL CONTINUE UNTIL
FRIDAY EVENING. REFER TO NWS PRODUCT ID PDXRFWPDT FOR MORE DETAILS.

AS THE RIDGE SHIFTS EAST TONIGHT...INSTABILITY WILL BEGIN TO
DECREASE ALONG THE CASCADES THIS EVENING. CRITICAL FIRE WEATHER
CONDITIONS SHOULD STILL CONTINUE THROUGH THIS EVENING. A RED FLAG
WARNING IS IN EFFECT FOR AREAS ALONG THE EAST SLOPES CENTRAL
WASHINGTON CASCADES. REFER TO NWS PRODUCT ID SEARFWSPO FOR MORE
DETAILS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

FIRE WEATHER WATCH FRIDAY
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, KITTITAS
     VALLEY, YAKIMA VALLEY, LOWER COLUMBIA BASIN OF WASHINGTON

RED FLAG WARNING FRIDAY
     EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON, EASTERN
     COLUMBIA RIVER GORGE OF WASHINGTON, 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, LOWER COLUMBIA
     BASIN OF OREGON, FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON,
     NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF
     OREGON, NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES

THUNDERSTORMS FRIDAY
     GRANDE RONDE VALLEY, WALLOWA COUNTY, SOUTHERN BLUE MOUNTAINS
     OF OREGON, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS

WINDS IN THE COLUMBIA RIVER GORGE AND LOWER COLUMBIA BASIN WILL
SUBSIDE LATER TONIGHT AND THEN REDEVELOP AND SPREAD FARTHER EAST
FRIDAY AFTERNOON AND EVENING. CRITICAL FIRE CONDITIONS WILL CONTINUE
IN THE LOWER COLUMBIA BASIN (FWZ 631) AND MAY SPREAD INTO THE
EASTERN WASHINGTON SOUTHERN COLUMBIA BASIN (FWZ 675). A RED FLAG
WATCH WILL CONTINUE FOR FWZ 631. A FIRE WEATHER WATCH IS IN EFFECT
BEGINNING LATE FRIDAY MORNING FOR FWZ 675. PLEASE REFER TO NWS
PRODUCT ID PDXRFWPDT FOR MORE DETAILS.

INCREASING MID LEVEL MOISTURE ON THE BACK SIDE OF AN UPPER HIGH
PRESSURE RIDGE WILL INCREASE THE RISK FOR LATE DAY THUNDERSTORMS
OVER THE CENTRAL AND EASTERN MOUNTAINS OF OREGON ON FRIDAY.
HOWEVER...THESE STORMS ARE NOT EXPECTED TO BECOME STRONG OR SEVERE.
THEY WILL STILL PRODUCE DANGEROUS LIGHTNING WITH POSSIBLE BRIEF
HEAVY RAIN.

.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.