Wildfire in Washington, July 9 to 11, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1030 PM PDT SUN JUL 8 2007

.SYNOPSIS...
WEST TO NORTHWEST FLOW ACROSS THE REGION WILL BRING SOME RELIEF
TO THE WARM TEMPERATURES THROUGH MONDAY. BY TUESDAY HIGH PRESSURE
WILL AGAIN DOMINATE THE PACIFIC NORTHWEST FOR A WARMING TREND
THROUGH THE MIDDLE OF THE WEEK.

&&

.DISCUSSION...
TONIGHT THROUGH WEDNESDAY...ANOTHER VERY QUIET PERIOD IS ON TAP FOR
THE ENTIRE FORECAST AREA THROUGH MID-WEEK. WITH A SMALL POTENTIAL
VORTICITY ANOMALY CURRENTLY BEING SEVERELY SHEARED AS IT OVERTOPS A
FORMING RIDGE OFF THE WEST COAST OF NORTH AMERICA SET TO DIVE
SOUTHEASTWARD DOWN THE CONTINENTAL DIVIDE THROUGH MONDAY AND EMERGE
WELL EAST OF THE CWA BY MONDAY NIGHT...VERY LITTLE IN THE WAY OF
SYNOPTIC SCALE WEATHER WILL AFFECT OUR CWA. WITH INSTABILITY
NON-EXISTENT AND ANY MOISTURE ASSOCIATED WITH THE PV ANOMALY AND
ASSOCIATED SHORT WAVE TO OUR NORTHEAST MONDAY VERY LIMITED...ANOTHER
DAY WITH NEARLY CLEAR SKIES ACROSS THE AREA SEEMS TO BE A GOOD BET.
ADDITIONALLY...GIVEN THAT ALL GLOBAL GUIDANCE IN LINE WITH THE
MESOSCALE MODELS THROUGH THE PERIOD...CONFIDENCE IS VERY HIGH IN THE
CUT OFF LOW OFF THE CENTRAL CALIFORNIA COAST CREATING STRONG
SOUTHERLY AND SOUTHEASTERLY UPPER FLOW FROM THE DESERT SOUTHWEST
TOWARD THE NORTHERN PACIFIC. AS IT DOES SO...A SPRAWLING ANTI-CYCLONE
DEVELOPS IN SHORT ORDER OVERNIGHT TONIGHT OFF THE OREGON COAST AND
EFFECTIVELY BLOCKS LARGE SCALE FLOW OVER THE CWA BY MONDAY. WITH THE
FORMATION OF THE INCREASINGLY SPRAWLING ANTI-CYCLONE AND ASSOCIATED
RIDGE AXIS EXTENDED FROM THE FOUR CORNERS AREA TOWARD THE AREA WELL
OFF SHORE OF WESTERN WASHINGTON...THE LOWER LEVELS OF THE ATMOSPHERE
WILL BEGIN TO WARM GREATLY THROUGH THE PERIOD...ESPECIALLY OVER THE
WESTERN CWA. DURING THE MONDAY THROUGH TUESDAY PERIOD...WITH THE
SURFACE THERMAL TROUGH STILL LOCATED OVER WESTERN WASHINGTON AND
OREGON UNDERNEATH THE MOST PRONOUNCED RIDGING ALOFT...SURFACE
TEMPERATURES ACROSS THE WESTERN CWA WILL LIKELY BEGIN TO EDGE CLOSER
TO 100 DEGREES AS 850 MB TEMPERATURES RISE TO THE MID 20S CELSIUS.
ACROSS THE EASTERN PORTION OF THE CWA...TEMPERATURES WILL LIKELY BE
A BIT SLOWER TO TREND STRONGLY UPWARD. BY WEDNESDAY...WITH RIDGING
STARTING TO SLIP A BIT FARTHER EAST AND THE SURFACE THERMAL TROUGH
LIKELY STRADDLING THE CASCADES...850 MB TEMPERATURES FINALLY GET A
GOOD PUSH UPWARD OVER THE BULK OF THE CWA. AS A RESULT...WITH CLEAR
SKIES AND STRONG INSOLATION YIELDING VERY GOOD
MIXING...TEMPERATURES WILL RISE INTO THE MID TO UPPER 90S
EVERYWHERE...WITH 100S A PRETTY GOOD BET FOR THE WESTERN CWA BY
THAT TIME. THROUGH THIS PERIOD OF THE FORECAST...THE MEX HAS A
DECENT HANDLE ON THINGS...SO DID NOT STRAY TOO FAR FROM GUIDANCE
FOR TEMPERATURES. /FRIES

WEDNESDAY NIGHT THROUGH SUNDAY...MEDIUM RANGE MODELS ARE IN GOOD
AGREEMENT SHOWING STRONG AMPLIFICATION OF THE WESTERN CONUS
RIDGE/EASTERN CONUS TROUGH PATTERN THIS PERIOD. THIS LARGE-
SCALE AMPLIFICATION WILL BE FORCED BY AN OVERALL DEEPENING OF THE
CLOSED LOW OVER THE EPAC JUST SOUTHWEST OF 40N/130W AS WELL AS
SHORT-WAVE PROGRESSION THROUGH THE BASE OF THE GULFAK UPPER
TROUGH/CLOSED LOW.  THE RESULTANT RIDGE AMPLIFICATION OVER OUR AREA
WILL TRANSLATE TO BUILDING HEAT ACROSS THE INLAND NORTHWEST FOR THE
LATTER HALF OF THE WORK WEEK...WITH RECORD OR NEAR RECORD HEAT AGAIN
LIKELY THU/FRI. DEJA VU ALL OVER AGAIN.

INITIALLY...THE MID-LEVEL RIDGE AXIS WILL TAKE ON A NW-SE ORIENTATION
OVER THE CWA LATE WEDNESDAY BEFORE BECOMING MORE N-S AND GRADUALLY
SHIFTING EAST OF THE CWA LATE FRIDAY. SO CONFIDENCE IN A WARMING AND
DRYING TREND IS QUITE HIGH WITH AN OVERALL DECREASE IN SURFACE WINDS
AS THEY TEND MORE TOWARD A TYPICAL DIURNAL REGIME. THE ASSOCIATED
LOW LEVEL THERMAL RIDGE FORECAST BY BOTH THE GFS AND ECMWF TO
STRENGTHEN LATE WEDNESDAY AND ESPECIALLY DURING THE THU/FRI TIME
PERIOD. BY 00Z FRI...THE GFS SHOWS 850 MB TEMPS REACHING 27-30C
RANGE WHILE THE ECMWF IS ABOUT A DEGREE COOLER.  BY 00Z SAT...850 MB
TEMPS WARM ANOTHER 3-4 DEGREES ACCORDING TO THE GFS WITH 29-32C
PRETTY COMMON AREAWIDE AND APPROACHING 34C ACROSS THE FAR SOUTHEAST.
AGAIN...THE ECMWF IS ABOUT 1-2 DEGREES COOLER BUT STILL SHOWING A
SIMILAR TREND.  LOOKING AT GFS BUFKIT DATA SUGGESTS MAX TEMPS IN
THE SPOKANE AREA WILL EASILY EXCEED TRIPLE DIGITS...AND COULD BE
EVEN HOTTER THAN WHAT WE EXPERIENCED LAST WEEK.  850 MB TEMPS WITH
LAST WEEK/S HEAT WAVE PEAKED AT 27C ON THE KOTX SOUNDING. ADJUSTED
TEMPS UP A LITTLE BASED ON LATEST GUIDANCE AND TRENDS.

ASIDE FROM THE BUILDING HEAT...THE OTHER FORECAST CHALLENGE THIS
PERIOD WILL BE THE POTENTIAL FOR CONVECTION MOVING UP INTO THE
CENTRAL AND SOUTH-CENTRAL CASCADES THURSDAY EVENING...AND
REDEVELOPING ALONG THE CASCADE CREST ON FRIDAY. THE CLOSED LOW
MENTIONED EARLIER IS FORECAST TO OPEN UP AND INTO WHAT IS DEPICTED BY
THE GFS TO BE A FAIRLY POTENT SHORT-WAVE TROUGH THAT LIFTS N-NEWD
FROM COASTAL OREGON ON FRIDAY. THE PREVIOUS FORECAST INCLUDED LOW END
CHC POPS ALONG THE CASCADES FOR THU NIGHT INTO FRIDAY AND SEE NO
REASON TO CHANGE THAT. IN FACT...I ACTUALLY EXPANDED THE COVERAGE A
BIT TO INCLUDE MORE OF THE NORTH CASCADES ON FRIDAY. THIS COULD END
UP BEING A POTENTIALLY CRITICAL PATTERN FOR FIRE WEATHER... AND WE
MAY NEED TO EXPAND THE MENTION OF THUNDER FARTHER EAST THAN
CURRENTLY DEPICTED FOR FRIDAY NIGHT. IN ADDITION...LOCALLY GUSTY
WINDS ARE LIKELY THROUGH THE GAPS AS THE CROSS CASCADE GRADIENT
INCREASES.

BEYOND FRIDAY NIGHT...SWLY FLOW ALOFT WILL DOMINATE THROUGH THE END
OF THE PERIOD AS THE RIDGE FLATTENS AND SHIFTS EAST.  WILL KEEP SOME
ISOLD SHRA/TSRA ACTIVITY NEAR THE CREST ON SAT...OTHERWISE DRY WITH
TEMPS TRENDING CLOSER TO SEASONAL.  ALSO...GUSTY AFTERNOON WINDS MAY
BECOME MORE PREVALENT NEXT WEEKEND WITH DIURNAL MIXING OF THE FASTER
WINDS ALOFT DOWNWARD. KJ

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH 06Z TUESDAY.
&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        58  89  59  92  63  97 /   0   0   0   0   0   0
COEUR DALENE  54  88  54  90  58  96 /   0   0   0   0   0   0
PULLMAN        52  87  49  89  54  93 /   0   0   0   0   0   0
LEWISTON       63  95  62  97  65 102 /   0   0   0   0   0   0
COLVILLE       51  90  52  93  53  98 /   0   0   0   0   0   0
SANDPOINT      51  86  52  89  55  94 /   0   0   0   0   0   0
KELLOGG        54  87  55  89  59  96 /   0   0   0   0   0   0
MOSES LAKE     60  95  60  99  63 101 /   0   0   0   0   0   0
WENATCHEE      65  95  65  97  68 102 /   0   0   0   0   0   0
OMAK           59  96  60  99  65 102 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&