FNUS76 KSEW 281502
FWSSEW

SPOT FORECAST FOR TA 18 PRAIRIE 2...FT LEWIS FORESTRY
NATIONAL WEATHER SERVICE SEATTLE WA
802 AM PDT MON SEP 28 2009

FORECAST IS BASED ON IGNITION TIME OF 1200 PDT ON SEPTEMBER 28.
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE IN SEATTLE.

.DISCUSSION...A DEEP AND COOL UPPER LEVEL TROUGH WILL APPROACH THE
REGION TODAY...THEN MOVE OVERHEAD TUESDAY BEFORE HEADING EAST ON
WEDNESDAY.  AS THE TROUGH AXIS PASSES OVER THE AREA TUESDAY THE AIR
MASS WILL BECOME UNSTABLE ENOUGH FOR A THREAT OF A THUNDERSTORM.  A
SHORTWAVE RIDGE WILL CREST OVER THE NW WEDNESDAY EVENING FOLLOWED
BY SEVERAL WEAK SYSTEMS THURSDAY AND FRIDAY.  AN UPPER LEVEL LOW
WILL SLIDE SOUTH ACROSS WASHINGTON THIS WEEKEND.

NOTE...THE GRAY ARMY AIRFIELD AND OLYMPIA AIRPORT OBSERVATIONS
WERE USED IN MAKING THIS FORECAST.

 FORECAST FOR 20 FOOT WIND SPEED (VALLEYS AND RIDGE TOPS) ARE 10
 MINUTE AVERAGES REFLECTING RAWS WINDS.

.TODAY...

SKY/WEATHER.........INCREASING CLOUDINESS WITH A CHANCE OF RAIN BY
                    MID AFTERNOON.
CWR.................10%.
MAX TEMPERATURE.....AT IGNITION 58-62 WITH A MAX OF 63-65.
MIN HUMIDITY........57-61 PERCENT WITH A MIN OF 45-51 PERCENT.
WIND (20 FT)........
 SLOPE/VALLEY.......SOUTH TO SOUTHEAST 3 TO 6 MPH AT IGNITION BECOMING
                    SOUTHWEST TO WEST WEST WINDS 7 TO 10 MPH WITH GUSTS
                    15 TO 19 MPH AT TIMES BY MID AFTERNOON.
MIXING HEIGHT.......100-300 FT AGL INCREASING TO 6300 FT AGL LATE IN THE
                    MORNING.
TRANSPORT WINDS.....SOUTH 8 TO 12 MPH.
HAINES MID-LEVEL....4 OR LOW.
       HIGH-LEVEL...3 OR VERY LOW.
RAINFALL AMOUNT.....0.02 INCHES.

.TONIGHT...

MIXING HEIGHT.......6300 FT AGL DECREASING TO 2700 FT AGL LATE IN
                    THE EVENING.
TRANSPORT WINDS.....SOUTHWEST 10 TO 14 MPH.
RAINFALL AMOUNT.....0.10 INCHES.

$$
FORECASTER...PRANGE
REQUESTED BY...DAN LEEPER
TYPE OF REQUEST...PRESCRIBED
.TAG 20090928.TA18P.01/SEW