National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KPDT 230527 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1027 PM PDT WED MAY 22 2013

UPDATED AVIATION DISCUSSION

.UPDATE...SHOWER ARE DECREASING IN INTENSITY AND COVERAGE OVER
EASTERN WASHINGTON AND OREGON WITH THE LOSS OF DAYTIME HEATING. AN
UPPER LEVEL LOW IS STILL SPINNING WEST OF YAKIMA AND ELLENSBURG.
SOME SHOWERS WILL PERSIST OVERNIGHT IN THE UNSTABLE AIR
ASSOCIATED WITH THIS LOW. FREEZING TEMPERATURES WILL DEVELOP IN
PARTS OF CENTRAL OREGON..THE HIGHER ELEVATIONS OF THE SOUTHERN
FOOTHILLS OF THE BLUE MOUNTAINS...AND THE GRANDE RONDE VALLEY. A
FREEZE WARNING IS IN EFFECT FOR THE SOUTHERN FOOTHILLS AND GRANDE
RONDE VALLEY TONIGHT AND TOMORROW MORNING. AS THE LOW DRIFTS WEST
TOMORROW SHOWERS WILL REDEVELOP IN EASTERN WASHINGTON AND OREGON
WITH THE STRONGEST SHOWERS IN OREGON. COONFIELD

&&

.AVIATION...06Z TAFS...VFR CONDITIONS CONDITIONS WILL PREVAIL
TONIGHT. SHOWERS WILL REMAIN ISOLATED OVERNIGHT THEN INCREASE AGAIN
AFTER 20Z. THE HEAVIEST SHOWERS WILL BE NEAR RDM AND BDN, BUT
SHOWERS ARE POSSIBLE AT ALL TAF LOCATIONS. MVFR CONDITIONS ARE
POSSIBLE NEAR SHOWERS 21-03Z. WINDS WILL BE GENERALLY LESS THAN 10
KTS UNTIL 18Z.  76

&&

.PREV DISCUSSION... /ISSUED 333 PM PDT WED MAY 22 2013/

SHORT TERM...TONIGHT THROUGH SATURDAY...A DEEP CLOSED LOW CONTINUES
TO SPIN OVER CENTRAL WASHINGTON.  SNOW WILL GRADUALLY DECREASE
ACROSS NORTHERN KLICKITAT COUNTY ABOVE 2500 FEET INTO EARLY THIS
EVENING.  WINTER STORM WARNING REMAINS IN EFFECT TIL 8 PM.

THE COLD AIRMASS ASSOCIATED WITH THIS SYSTEM WILL BRING TEMPERATURES
DOWN TO THE UPPER 20S ACROSS THE SOUTHERN FOOTHILLS OF THE BLUE
MOUNTAINS AND GRANDE RONDE VALLEY OF OREGON.  A FREEZE WARNING HAS
BEEN ISSUED FOR THESE AREAS. CENTRAL OREGON WILL ALSO FREEZE UNDER
THE EFFECTS OF THE UNSEASONABLY COLD AIR...BUT FREEZE WARNINGS ARE
NOT NORMALLY ISSUED FOR THOSE AREAS UNTIL AFTER JUNE 1.

SHORT TERM MODELS IN GOOD AGREEMENT WITH UPPER LOW WOBBLING AROUND
THE PACIFIC NORTHWEST THROUGH FRIDAY AND THEN LIFTING OUT FRIDAY
NIGHT.  AS SUCH...VERY COOL AND SCATTERED SHOWERY CONDITIONS WILL
PREVAIL THURSDAY. SHOWERS WILL LIKELY SHOW AN INCREASE ON LATE
THURSDAY NIGHT AND FRIDAY AND THE LOW TRACKS NORTHEAST FROM CENTRAL
OREGON TO NORTHERN IDAHO. A DRIER WESTERLY FLOW SHOULD PREVAIL FOR
ALL AREAS ON SATURDAY...EXCEPT THE CREST OF THE WA/OR CASCADES AND
THE EASTERN MOUNTAINS WHERE A FEW SHOWERS WILL LINGER.

LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY NIGHT...UPPER LEVEL
TROUGH WILL CONTINUE TO CIRCULATE OVER THE PACIFIC NORTHWEST FOR THE
EXTENDED.  IT DOES SHOW SIGNS OF WEAKENING AND WARMER AIR
INTRUDING...BUT OVERALL UNSETTLED WEATHER CAN BE EXPECTED EVERY
DAY...WITH THE BETTER CHANCES OF SHOWERS AND POSSIBLY THUNDERSTORMS
TO BE OVER THE MOUNTAINS.  MODELS DO HINT AT A WEAK WAVE TO PUSH
THROUGH SATURDAY EVENING...WHICH MIGHT GENERATE A FEW MOUNTAIN
THUNDERSTORMS ACROSS NORTHEAST OREGON. AS THE CENTER OF THE LOW
PUSHES NORTHWARD FOR THE MAJORITY OF THE WORK WEEK...THE FORECAST
AREA FOR THE MOST PART WILL BE IN A ZONAL FLOW.  THIS WILL SUPPORT
NEAR NORMAL TEMPERATURES...BUT ALSO A CHANCE FOR SHOWERS EACH DAY.
MODELS DO HINT AT ANOTHER POTENTIALLY STRONG COLD FRONT TO MOVE
THROUGH ON WEDNESDAY AFTERNOON.  THE SYSTEM THAT IS MOVING IN LOOKS
TO HAVE A SLIGHT NEGATIVE TILT...ALONG WITH CAPE VALUES AND LI`S
INDICATE THE POTENTIAL FOR THUNDER.  THEREFORE HAVE MADE A SLIGHT
CHANCE MENTION INTO THE FORECAST FOR WEDNESDAY.  WEBER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  34  59  42  60 /  20  20  20  50
ALW  36  63  44  61 /  20  20  20  40
PSC  37  65  45  66 /  20  20  20  40
YKM  36  63  43  65 /  60  20  20  40
HRI  34  65  45  63 /  20  20  20  50
ELN  34  61  41  63 /  60  30  30  40
RDM  25  55  35  55 /  20  20  50  40
LGD  30  57  38  54 /  30  30  30  50
GCD  28  54  35  51 /  30  30  30  50
DLS  38  62  46  62 /  20  20  50  50

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY ORZ508.

     FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY
     ORZ049.

WA...NONE.

&&

THREAT INDEX
THURSDAY : GREEN
FRIDAY : GREEN
SATURDAY : GREEN

GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

76/76/76