FNUS76 KSEW 180522
FWSSEW

SPOT FORECAST FOR RAINBOW BRIDGE...NPS NORTH CASCADES
NATIONAL WEATHER SERVICE SEATTLE WA
1022 PM PDT TUE AUG 17 2010

FORECAST IS BASED ON REQUEST TIME OF 2203 PDT ON AUGUST 17. IF
CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER
SERVICE IN SEATTLE.

.DISCUSSION...THE DRY AND UNSTABLE AIR MASS WILL CONTINUE TO MOVE TO
THE EAST OVERNIGHT IN RESPONSE TO INCREASED ONSHORE FLOW. THIS WILL
WILL RESULT IN THE MARINE LAYER PENETRATING INLAND TO THE CASCADES
BY WEDNESDAY MORNING /BELOW ABOUT 3000 FEET/...WHICH WILL COOL AND
MOISTEN THE AIR MASS. IT IS POSSIBLE THAT THE MARINE LAYER MAY REACH
AS HIGH AS ABOUT 4500 FEET WEDNESDAY MORNING. TEMPERATURES ALOFT
WERE ALSO GRADUALLY COOLING AS THE UPPER RIDGE MOVES OFF TO THE EAST.

THE MARINE LAYER WILL DEEPEN WEDNESDAY NIGHT INTO THURSDAY...FORCING
MOISTURE TO THE CREST OF THE CASCADES FOR HIGHER HUMIDITIES AND COOLER
TEMPERATURES. AFTERNOON RELATIVE HUMIDITIES WILL INCREASE WITH THE
MOIST MARINE AIR SPILLING OVER THE MOUNTAINS.

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

.WEDNESDAY...
SKY/WEATHER.........MOSTLY SUNNY.
CWR.................LESS THAN 10%.
MAX TEMPERATURE.....78-88.
MIN HUMIDITY........23-37 PERCENT.
HAINES INDEX........5 OR MODERATE.
LAL.................1.
WIND (20 FT)........
 LWR SLP/VALLEY.....UPSLOPE WINDS 2 TO 5 MPH.

.WEDNESDAY NIGHT...
SKY/WEATHER.........MOSTLY CLEAR.
CWR.................LESS THAN 10%.
MIN TEMPERATURE.....52-62.
MAX HUMIDITY........69-84 PERCENT.
HAINES INDEX........4 OR LOW.
LAL.................1.
WIND (20 FT)........
 LWR SLP/VALLEY.....DOWNSLOPE 3 TO 8 MPH.

.THURSDAY...
SKY/WEATHER.........MOSTLY SUNNY.
CWR.................LESS THAN 10%.
MAX TEMPERATURE.....73-83.
MIN HUMIDITY........22-36 PERCENT.
HAINES INDEX........3 OR VERY LOW.
LAL.................1.
WIND (20 FT)........
 LWR SLP/VALLEY.....UPSLOPE 2 TO 5 MPH.

$$
FORECASTER...05
REQUESTED BY...AARON ANDERSON
TYPE OF REQUEST...WILDFIRE
.TAG 20100817.RAINB.01/SEW