Flash Flood Warning 1, NWS Pendleton, OR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
447 AM PDT TUE SEP 18 2007

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...A NORTHWEST FLOW WILL
DOMINATE CONDITIONS WITH INCREASING WINDS ALOFT AS A WEATHER SYSTEM
DROPS DOWN FROM THE GULF OF ALASKA INTO THE PACIFIC NORTHWEST TODAY
AND TONIGHT. CLOUDS ARE BEING ENHANCED EARLY THIS MORNING OVER
WESTERN AND CENTRAL OREGON AS HIGHER LEVEL WIND SPEEDS INCREASE OVER
THE CASCADES AND HELP TO ENHANCE CLOUD DEVELOPMENT. THIS CORRESPONDS
WELL WITH AN UPPER JET STREAM WIND MAXIMUM OF AROUND 90-100 KTS OVER
THE CREST OF THE CASCADES. AS THIS UPPER JET CONTINUES TO SAG
SOUTHWARD TONIGHT...THE FORECAST AREA WILL BECOME ENTRENCHED BETWEEN
A JET COUPLET IN AN UPPER TROUGH. THESE DYNAMIC FEATURES COMBINED
WITH DECREASED STABILITY AND INCREASING MOISTURE WILL LEAD TO
INCREASING SHOWERS TODAY AND TONIGHT. SHOWERS MAY BECOME A MORE
GENERAL STRATIFORM RAIN EVENT FOR A PERIOD OF TIME ON WEDNESDAY
DURING THE TIME OF THE MAXIMUM DYNAMIC LIFTING OVER THE FORECAST
AREA...WHICH WILL BE FROM ABOUT 12Z WED - 00Z THURS. DURING THAT
TIME PERIOD THE UPPER TROUGH WILL BECOME A CLOSED CIRCULATION WITH
THE CWA ON THE SOUTHERLY FLOW SIDE OF THIS UPPER LOW. THIS UPPER LOW
PRESSURE SYSTEM WILL CONTINUE TO DROP SOUTHWARD...INTO NORTHERN
CALIFORNIA OVERNIGHT WEDNESDAY THROUGH EARLY THURSDAY. THIS WILL
ALLOW PRECIPITATION COVERAGE AND INTENSITY TO DECREASE OVERNIGHT
WEDNESDAY NIGHT. TEMPERATURES WILL REMAIN COOLER THAN NORMAL THROUGH
THE SHORT TERM PERIOD DUE TO COLDER AIR MOVING IN ALOFT AS WELL AS
CLOUDY SKIES AND PRECIPITATION COOLING EFFECTS. IMPROVEMENT IS
EXPECTED DURING THE EXTENDED PERIOD. 88

.LONG TERM...THURSDAY THROUGH MONDAY...REGION LOOKS TO BE UNDER WEAK
HIGH PRESSURE ALOFT THURSDAY AND FRIDAY. THUS SHOULD SEE MOSTLY FAIR
AND DRY CONDITIONS BOTH DAYS. ANOTHER SYSTEM WILL MOVE INTO THE
PACNW FROM THE EASTERN PACIFIC SATURDAY. AT THE SAME TIME THE UPPER
LOW NEAR SOUTHERN CALIFORNIA WILL BE KICKED NORTH-NORTHEAST TO IDAHO
ON SATURDAY. THUS SHOULD SEE SOME SHOWERS ALONG THE CASCADE CREST...
AND OVER PORTIONS OF CENTRAL AND NORTHEAST OREGON SATURDAY AND
SATURDAY NIGHT. FOR NOW WILL CONTINUE CURRENT FORECAST OF SLIGHT
CHANCE SHOWERS OVER THE MOUNTAINS SUNDAY AND MONDAY...THOUGH HIGH
PRESSURE BUILDING INTO THE REGION ON THESE DAYS MAY COMPLETELY DRY
OUT AND STABILIZE THE AIR MASS OVER THE REGION. 90

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE TAF SITES DURING THE
NEXT 24 HOURS. MID AND HIGH CLOUD CEILINGS THIS MORNING SHOULD
SCATTER OUT BY LATE MORNING. THE HIGH CLOUDS WILL THICKEN AFTER
19/00Z. THEN CEILINGS BETWEEN 6000 AND 8000 FEET AGL...ALONG WITH
VICINITY SHOWERS...WILL DEVELOP AT KRDM...KPDT AND KALW AFTER
19/08Z. ELSEWHERE...A FEW SHOWERS...WITH LOCALLY LOWER CEILINGS...
WILL DEVELOP OVER THE MOUNTAINS DURING TODAY AND PERSIST THROUGH
TONIGHT. 90

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  44  64  45 /  10  30  50  20
ALW  67  48  66  49 /  10  30  40  10
PSC  70  45  69  46 /  10  20  30  10
YKM  66  40  65  41 /  10  20  30  10
HRI  69  45  68  46 /  10  20  30  10
ELN  65  40  64  41 /  10  20  30  10
RDM  63  35  62  36 /  10  20  40  20
LGD  61  42  60  43 /  30  30  50  20
GCD  65  38  64  39 /  20  30  60  30
DLS  65  49  64  50 /   0  20  30  10

&&

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

TI:GGG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
88/90/90

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
500 AM PDT TUE SEP 18 2007

CORRECTED TRANSMISSION TIME

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-191115-
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-
500 AM PDT TUE SEP 18 2007

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

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

AN UPPER LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION BRINGING WITH
IT COOLER AIR AND ABUNDANT MOISTURE. THIS WILL CAUSE SCATTERED TO
NUMEROUS RAIN OR RAIN SHOWERS TO DEVELOP BY THIS AFTERNOON AND
TONIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

COOLER TEMPERATURES WITH RAIN OR RAIN SHOWERS ARE EXPECTED TO
CONTINUE ON WEDNESDAY AND THEN DECREASE WEDNESDAY NIGHT AND EARLY
THURSDAY. WARMER AND DRIER CONDITIONS WILL RETURN ON THURSDAY
THROUGH THE WEEKEND WITH A WARMING TREND AS HIGH PRESSURE ALOFT
REBUILDS OVER THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

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.