Wildfire in Oregon, July 24 to 30, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
810 PM PDT THU JUL 23 2009

.UPDATE...AN UPPER TROUGH IS CURRENTLY MOVING INTO NORTHERN AND
WESTERN WASHINGTON THIS EVENING AND IS TAKING A TRACK ACROSS THE
NORTHERN TIER OF THE STATE. IT WILL SLOW DOWN OVER NORTHEAST
WASHINGTON BY FRIDAY AFTERNOON AND THEN THERE IS UNCERTAINTY WHAT IT
WILL DO. THE LATEST 00Z NAM12 MODEL RUN RETROGRADES BACK WESTWARD
ACROSS NORTHERN WASHINGTON WHILE THE LATEST 18Z GFS40 RUN CONTINUES
IT EASTWARD INTO NORTHERN IDAHO INTO SATURDAY. WITH THESE MODEL
UNCERTAINTIES WILL MAINLY CONCENTRATE ON THE NEXT 24 HOURS THIS
EVENING AND LET THE MID SHIFT EVALUATE THE 00Z GFS40 AND OTHER
MODELS WHEN THEY ARRIVE. SO FAR THIS SYSTEM HAS BROUGHT SEVERE
WEATHER TO NORTH AND NORTHEAST WASHINGTON WITH MAINLY JUST DRY DUSTY
WINDS OVER THE KPDT FORECAST AREA. SOME OF THESE WINDS HAVE NEARED
THE CRITERIA FOR A WIND ADVISORY BUT DID NOT MEET THE TIME CRITERIA.
THEREFORE HAVE BEEN HANDLING THEM WITH SPECIAL SHORT TERM FORECASTS.
MAY NEED TO INCREASE THE WIND FORECAST FOR THE OVERNIGHT HOURS...BUT
FORECAST WIND AND GRADIENT TRENDS ARE FOR A DECREASE AT ALL AREAS
BEGINNING AND AFTER AROUND SUNSET. SLIGHTLY COOLER BUT CONTINUED DRY
CONDITIONS ARE EXPECTED FOR FRIDAY AS THE UPPER LOW CONTINUES TO
STAY FAR ENOUGH TO THE NORTH TO HAVE LITTLE ADDITIONAL EFFECT ON THE
FORECAST AREA. 88

&&

.AVIATION...060Z TAFS...WINDS OF 15 TO 25 MPH WILL PREVAIL AT MOST
TAF SITES UNTIL SUNSET AND THEN WILL DECREASE OVERNIGHT TO UNDER 15
KTS BY 12Z FRIDAY. VFR CONDITIONS ARE OTHER WISE EXPECTED WITH JUST
SOME MID AND HIGH CLOUDS THROUGH THE NEXT 24 HOURS. 88

&&

.PREV DISCUSSION... /ISSUED 155 PM PDT THU JUL 23 2009/

SHORT TERM...TONIGHT THROUGH SUNDAY...WATER VAPOR IMAGERY SHOWS A
LOW PRESSURE SYSTEM MOVING ACROSS WASHINGTON THIS AFTERNOON. MOST OF
THE DYNAMICS HAVE BEEN AHEAD OF A DISTURBANCE ROTATING AROUND THE
LOW IN CENTRAL AND NORTHERN WASHINGTON. A FEW CUMULUS ARE BUILDING
ACROSS THE EAST SLOPES OF THE CENTRAL CASCADES AND AN ISOLATED
THUNDERSTORM MAY BE POSSIBLE THERE THIS AFTERNOON AND EVENING. THE
LOW IS SUPPRESSING THE RIDGE AND PUSHING MOISTURE FROM THE DESERT
SOUTHWEST FURTHER SOUTH OF THE AREA. COOLER MARINE AIR CONTINUES TO
FILTER THROUGH THE CASCADE GAPS AND IS LEADING TO BREEZY TO WINDY
CONDITIONS IN THE COLUMBIA RIVER GORGE...KITTITAS VALLEY AND
PORTIONS OF THE COLUMBIA BASIN.

THE LOW IS THEN EXPECTED TO VERY SLOWLY MOVE THROUGH WASHINGTON
TOWARD THE IDAHO BORDER TONIGHT AND FRIDAY. THIS WILL KEEP THE RIDGE
SUPPRESSED OVER THE REGION AND KEEP HIGH TEMPERATURES IN THE LOWER
TO MID 90S FOR THE LOWER ELEVATIONS AND IN THE 80S FOR THE MOUNTAINS
ON FRIDAY. INSTABILITY WITH THE LOW PRESSURE SYSTEM WILL REMAIN
PRIMARILY NORTH OF THE AREA ON FRIDAY. WHILE MOST OF THE REGION WILL
REMAIN STABLE...SOME UNSTABLE AIR OVER WALLOWA COUNTY MIGHT CAUSE A
SLIGHT CHANCE OF THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. THOUGH
IF THE LOW CONTINUES TO SLOW DOWN AS RECENT MODEL RUNS
INDICATE...CONVECTION MAY REMAIN NORTH OF THE AREA.

DURING THE WEEKEND THE LOW WILL START TO DROP SOUTHEASTWARD ACROSS
IDAHO AND MONTANA. THE BACKSIDE OF THE LOW WILL PASS OVER FAR
NORTHEAST OREGON AND THERE IS A BETTER CHANCE FOR THUNDERSTORM
DEVELOPMENT SATURDAY AND SUNDAY EAST OF THE BLUE MOUNTAINS AS
MOISTURE ROTATES AROUND THE SYSTEM. WITH THE LOW MOVING EAST...THE
RIDGE WILL BUILD ONCE AGAIN TOWARD THE WEST WITH WARMING
TEMPERATURES FOR THE COLUMBIA BASIN AND WESTWARD ON SUNDAY. DMH

LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...GENERALLY STAGNANT
PATTERN WITH BLOCKING LONG WAVE RIDGE OVER WEST COAST...BUT MINOR
DAY TO DAY CHANGES. RATHER VIGOROUS SHORT WAVE DIVES SOUTH ON EAST
SIDE OF RIDGE TUESDAY THROUGH THURSDAY.  GFS SOLUTION DIGS THIS
SHORTWAVE TROUGH INTO EXTREME EASTERN WASHINGTON AND OREGON WHILE
ECMWF MODEL KEEPS THE SHORTWAVE FURTHER EAST.  TO ACCOUNT FOR THIS
UNCERTAINTY...HAVE PUT SLIGHT CHANCE POPS IN FOR EXTREME NORTHEAST
MOUNTAINS ON WEDNESDAY WITH REST OF AREA DRY AND CONTINUING ABOVE
NORMAL TEMPERATURES. PROBABLY NEED HEAT ADVISORY AGAIN FOR COLUMBIA
BASIN EARLY NEXT WEEK WITH SEVERAL DAYS OF TRIPLE DIGIT HIGH
TEMPERATURES.
HULL

FIRE WEATHER...TRACK OF THE UPPER LEVEL LOW THROUGH WASHINGTON DOES
NOT FAVOR THE PENDLETON FORECAST AREA WITH MUCH THUNDERSTORM
ACTIVITY OVER THE NEXT COUPLE OF DAYS. BEST CHANCE OCCURS OVER
SOUTHEAST WASHINGTON AND FAR NORTHEAST OREGON BUT LOOKING AT JUST
ISOLATED AT BEST AND THATS IF THEY EVEN OCCUR. ONLY OTHER CONCERN IS
SOME LOCALLY BREEZY CONDITIONS THROUGH THIS EVENING ALONG THE EAST
SLOPES OF THE CASCADES SPILLING OUT INTO THE COLUMBIA BASIN. WINDS
WILL DECREASE OVERNIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  60  93  63  95 /   0  10  10  10
ALW  65  93  64  96 /  10  10  10  10
PSC  63  94  64  98 /  10  10  10   0
YKM  60  92  64  95 /  10  10  10  10
HRI  61  94  62  97 /   0   0   0   0
ELN  60  91  62  97 /  20  10  10  10
RDM  45  91  47  93 /   0   0   0   0
LGD  54  90  53  92 /  10  10  10  20
GCD  54  92  56  92 /  10  10  10  10
DLS  61  94  63  96 /   0   0   0   0

&&

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

&&

THREAT INDEX
FRIDAY : GREEN
SATURDAY : GREEN
SUNDAY : GREEN

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

88/79/88

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
210 PM PDT THU JUL 23 2009

UPDATED HAZARDS

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-241415-
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-
210 PM PDT THU JUL 23 2009

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

.DAY ONE...TONIGHT

THUNDERSTORMS
     EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON, EAST SLOPES
     OF THE SOUTHERN CASCADES OF WASHINGTON, KITTITAS VALLEY,
     YAKIMA VALLEY

A LOW PRESSURE SYSTEM MOVING ACROSS WASHINGTON WILL INTRODUCE
ISOLATED THUNDERSTORMS OVER THE EAST SLOPES OF THE CENTRAL
WASHINGTON CASCADES THIS AFTERNOON AND EVENING. PRESSURE GRADIENTS
WILL REMAIN TIGHT THIS AFTERNOON WITH BREEZY TO WINDY CONDITIONS IN
THE COLUMBIA RIVER GORGE...KITTITAS VALLEY AND THE COLUMBIA BASIN
THROUGH THIS EVENING. WINDS ARE EXPECTED TO DECREASE OVERNIGHT AS
PRESSURE GRADIENTS RELAX.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS FRIDAY
     WALLOWA COUNTY

THUNDERSTORMS SATURDAY
     NORTHWEST BLUE MOUNTAINS, GRANDE RONDE VALLEY, WALLOWA COUNTY,
     NORTHERN BLUE MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF
     OREGON

EXCESSIVE HEAT SUNDAY
     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, LOWER COLUMBIA BASIN OF OREGON, FOOTHILLS OF
     THE BLUE MOUNTAINS OF OREGON

EXCESSIVE HEAT MONDAY AND TUESDAY
     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

A LOW PRESSURE SYSTEM WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS TO
THE MOUNTAINS FRIDAY AND SATURDAY BEFORE HIGH PRESSURE RETURNS ON
SUNDAY. THIS WILL BRING A RETURN TO HOT AND DRY CONDITIONS THAT WILL
CONTINUE THROUGH THE WEEKEND INTO NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TONIGHT THROUGH SATURDAY 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.