FXUS66 KPDT 201639 CCA
AFDPDT

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OREGON
940 AM PDT WED OCT 20 2004

...CORRECTED TO ADD EXTRA SENTENCE TO 1ST PARAGRAPH...

.SHORT TERM...AN IMPRESSIVE DEFORMATION BAND HAS SET UP OVER NE 
OREGON AND SE WASHINGTON.  PRECIPITATION AMOUNTS OF 0.25 TO 0.50 OF 
AN INCH HAVE ALREADY BEEN OBSERVED IN THE CENTRAL AND EASTERN 
MOUNTAIN WITH THIS SLOW MOVING BAND...AND AREAS IN THE JOHN DAY 
BASIN RECEIVED UP TO AN INCH OF PRECIPITATION THIS MORNING.  SNOW 
LEVELS AND SNOW AMOUNTS ARE TRICKY. CURRENT FORECAST HAS SNOW LEVELS 
ABOVE 5500 FEET...AND METAR/RAWS DATA SHOW TEMPERATURES AND 
DEWPOINTS IN THE LOWER TO MID 30S ABOVE 5000 FEET. 
HOWEVER...SPOTTERS IN THE JOHN DAY BASIN HAVE OBSERVED LIGHT SNOW 
ABOVE 4000 FEET.  HAVE ISSUED SHORT TERM FORECASTS TO INDICATE LIGHT 
SNOW OVER PORTIONS OF THE JOHN DAY BASIN.  ACCUMULATIONS IN THE JOHN 
DAY AND OCHOCO HIGHLANDS WILL BE 1-3 INCHES...JUST UNDER SNOW 
ADVISORY CRITERIA.  CURRENT FORECAST APPEARS ON TRACK BY LOWERING 
POPS LATER THIS AFTERNOON. HOWEVER...WILL NEED TO MAKE UPDATES IF 
THE SYSTEM IS EVEN SLOWER THAN WE EXPECT.  THE SYSTEM WILL SLOWLY 
MOVE EASTWARD AS THE DAY PROGRESSES...THUS OUR WESTERN ZONES WILL 
ONLY ISOLATED SHOWERS TODAY. SMITH

&&

.PREVIOUS DISCUSSION...OVERNIGHT THE LOW WILL TRACK EAST AND 
SOUTHWARD WITH NORTHWEST FLOW OVER-SPREADING THE AREA.  JUST ENOUGH 
LINGERING MOISTURE BEING DRAWN UPSLOPE INTO THE CASCADE AND BLUE 
MOUNTAINS IN THIS NORTHWEST FLOW WILL GENERATE SHOWERS IN THOSE 
AREAS.  BLUE MOUNTAIN FOOTHILL AREAS WILL SEE ISOLATED SHOWERS AS 
WELL ESPECIALLY EARLY ON DURING THE OVERNIGHT HOURS.

ANOTHER DISTURBANCE WITH A TRAILING COLD FRONT WILL IMPACT THE AREA 
THURSDAY NIGHT INTO FRIDAY.  MODEL FORECASTS ARE HINTING AT PRETTY 
STRONG WESTERLY FLOW ASSOCIATED WITH THIS FRONT.  THIS FLOW WILL 
AGAIN LIMIT PRECIPITATION AMOUNTS IN AREAS EAST OF THE CASCADES 
INCLUDING CENTRAL OREGON AND THE COLUMBIA BASIN.  MOUNTAIN AREAS 
WILL SEE A GOOD CHANCE OF PRECIPITATION.  WINDS WILL BE BREEZY IN 
MANY LOWLAND LOCATIONS AS THE FRONT MOVES THROUGH FRIDAY.  


FRIDAY NIGHT THROUGH TUESDAY...COOL AND UNSETTLED 
WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK...AS A SERIES OF 
SYSTEMS MOVE THROUGH THE PACIFIC NORTHWEST.  AT THIS TIME...MODELS 
ARE INDICATING THAT TWO STRONGER SYSTEMS WILL MOVE THROUGH THE 
REGION FRIDAY NIGHT INTO SATURDAY AND AGAIN MONDAY INTO 
TUESDAY...WITH THESE DAYS HAVING A BETTER CHANCE OF SEEING 
WIDESPREAD RAIN.  

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 055 040 058 / 040 020 010 
WALLA WALLA         058 043 060 / 040 020 010 
TRI-CITIES          060 041 061 / 030 010 010 
YAKIMA              060 037 059 / 020 010 010 
HERMISTON           060 041 061 / 030 010 010 
ELLENSBURG          057 038 056 / 020 010 010 
REDMOND             054 033 054 / 020 010 010 
LA GRANDE           051 036 053 / 060 020 020 
JOHN DAY            054 038 055 / 060 020 020 
THE DALLES          063 042 061 / 020 010 010 
&&

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

$$
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