Area Forecast Discussion
Issued by NWS Pendleton, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPDT 070229
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
729 PM PDT MON JUL 6 2015

.SHORT TERM...SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPED OVER
CENTRAL OREGON THIS AFTERNOON AND EARLY EVENING ASSOCIATED WITH AN
UPPER LOW OFF THE CALIFORNIA COAST. RADAR TRENDS INDICATE THE ACTIVITY
IS STARTING TO DIMINISH. EXPECT SOME SHOWERS TO CONTINUE FOR
SEVERAL MORE HOURS WITH PARTLY CLOUDY SKIES OVERNIGHT. THE
REMAINDER OF THE FORECAST AREA SHOULD BE CLEAR THIS EVENING AND
OVERNIGHT. NOT MUCH CHANGE TO THE OVERALL PATTERN TUESDAY AS THE
LOW REMAINS OFFSHORE. SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE OVER CENTRAL OREGON IN THE AFTERNOON AND EARLY EVENING.
REMAINDER OF THE FORECAST AREA WILL BE SUNNY. HIGH TEMPS WILL BE
SIMILAR TO TODAY. THE LOW MOVES INTO CALIFORNIA WEDNESDAY AND
THURSDAY. THIS SHOULD INCREASE THE COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER CENTRAL AND NORTHEAST OREGON...ESPECIALLY
THURSDAY. 94

&&

.PREV DISCUSSION... /ISSUED 430 PM PDT MON JUL 6 2015/

SHORT TERM...TONIGHT THROUGH THURSDAY...AN UPPER LEVEL DEFORMATION
ZONE WILL PERSIST ACROSS CENTRAL AND EAST-CENTRAL OREGON THROUGH
THIS EVENING. ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE TO
DEVELOP WITH THIS ZONE THROUGH THE REMAINDER OF THE AFTERNOON, THEN
PERSIST INTO THE EVENING. THESE STORMS MAY PRODUCE BRIEF DOWNPOURS
AND SMALL HAIL. A FEW HIGH BASED SHOWERS MAY LINGER OVER DESCHUTES
COUNTY AFTER MIDNIGHT. THIS DEFORMATION ZONE WILL SHIFT SLIGHTLY TO
THE SOUTH TUESDAY AND WEDNESDAY IN RESPONSE TO AN UPPER WAVE MOVING
THROUGH WASHINGTON AND MONTANA. AS SUCH CHANCES OF THUNDERSTORMS
WILL BE LIMITED TO PORTIONS OF DESCHUTES, CROOK, GRANT, UNION AND
WALLOWA COUNTIES AFTERNOONS AND EVENINGS TUESDAY AND WEDNESDAY.
COVERAGE OF THESE STORMS WILL MAINLY BE ISOLATED. AN UPPER LOW OFF
THE CALIFORNIA COAST STILL LOOKS ON TRACK TO MOVE INTO CALIFORNIA
AND NEVADA THURSDAY. THUS STILL EXPECT MID/HIGH LEVEL MOISTURE TO
SPREAD FURTHER INTO OUR AREAS THURSDAY AFTERNOON. AS A RESULT
CHANCES OF THUNDERSTORMS WILL INCREASE ACROSS CENTRAL AND EAST-
CENTRAL OREGON, WHILE LOWER CHANCES WILL SPREAD INTO OTHER PORTIONS
OF THE AREA. AT THIS TIME WILL KEEP MUCH OF THE GORGE, LOWER BASIN,
AND THE YAKIMA AND KITTITAS VALLEYS THUNDERSTORM FREE THROUGH
THURSDAY AFTERNOON. TEMPS WILL CONTINUE ABOVE SEASONAL THROUGH THIS
PERIOD. 90

LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT...A MUCH MORE
ACTIVE AND COOLER WEATHER PATTERN WILL PERSIST THROUGH MUCH OF THE
EXTENDED PERIOD. THURSDAY NIGHT INTO FRIDAY THE UPPER LOW THAT WAS
OVER CALIFORNIA WILL BEGIN TO EJECT AS A NEGATIVELY TILTED TROUGH
THROUGH THE REGION. AT THIS TIME IT DOES NOT APPEAR TO BE A
PARTICULARLY STRONG NEGATIVE TILT TROUGH...HOWEVER THE ADDED
VORTICITY COMBINED WITH DEEPER MID-LEVEL MOISTURE AND ENHANCED
INSTABILITY WILL LIKELY LEAD TO A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE REGION DURING THIS TIME. WITH THE
ADDED CLOUDS AND PRECIPITATION ALONG WITH LOWER 850MB TEMPS AND
LOWERING HEIGHTS EXPECT TEMPERATURES TO BE ON A DOWNWARD TREND
COMPARED TO THE BEGINNING OF THE WEEK. WILL ALSO NEED TO WATCH FOR
BREEZY CONDITIONS TO DEVELOP ACROSS PARTS OF OUR FORECAST AREA FOR
THURSDAY NIGHT AND FRIDAY AS A LOW PRESSURE SYSTEM MOVES THROUGH
EASTERN WASHINGTON. WESTERLY WINDS MAY INCREASE TO 15-25 MPH WITH
HIGHER GUSTS DURING THIS TIME. ANOTHER LARGE UPPER LEVEL TROUGH WILL
FOLLOW CLOSELY BEHIND THE FIRST SYSTEM AS IT DIVES TOWARD THE PAC NW
FROM THE GULF OF ALASKA...THIS TROUGH WILL LIKELY KEEP CONDITIONS
UNSETTLED WITH CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH THE
WEEKEND. TEMPERATURES WILL REMAIN COOLER THROUGH AT LEAST MONDAY.
HIGH TEMPERATURES ARE EXPECTED TO RANGE FROM THE LOWER 80S TO LOWER
90S FOR SUNDAY AND MONDAY IN THE LOWER ELEVATIONS WITH 60S AND 70S
IN THE MOUNTAINS...THIS WILL FINALLY BE BACK TO NEAR AVERAGE LEVELS.
77

AVIATION...00Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD AT ALL TAF SITES. KBDN AND KRDM WILL SEE TSRA AND/OR
VCTS THROUGH ABOUT 07/03Z THIS EVENING BEFORE THE TS MOVE EAST AND
DISSIPATE. OTHERWISE FOR THE OTHER TAF SITES EXPECT MAINLY CLEAR
SKIES WITH JUST A FEW MID AND UPPER LEVEL CLOUDS POSSIBLE INTO THE
OVERNIGHT HOURS. SKIES WILL REMAIN MAINLY CLEAR AGAIN
TOMORROW...EXCEPT AT KBDN WHERE THERE WILL BE SHOWERS AND POSSIBLY A
THUNDERSTORM DEVELOPING ONCE AGAIN AFTER 07/21Z. ALTHOUGH THERE
COULD BE AN ISOLATED SHOWER/STORM MOST OF THE ACTIVITY SHOULD REMAIN
SOUTH OF KRDM TOMORROW AFTERNOON...THEREFORE LEFT ANY MENTION OUT OF
THE TAF FOR NOW. WINDS WILL REMAIN ELEVATED THIS EVENING AT KDLS
WHERE WNW WINDS WILL BE BETWEEN 15-25KTS...THESE SHOULD DECREASE TO
NEAR 10KTS AFTER 07/07Z. WINDS WILL INCREASE AGAIN AT KDLS AFTER
07/19Z OUT OF THE NW AT 15-25KTS. OTHERWISE WINDS WILL GENERALLY BE
AOB 12KTS EXCEPT AT KBDN/KRDM THIS EVENING WHERE THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS AT TIMES MAINLY THROUGH 07/03Z. 77

FIRE WEATHER...RED FLAG WARNING IN EFFECT FOR FIRE WEATHER ZONES
OR610...611...AND...640 FOR THUNDERSTORMS WITH ABUNDANT LIGHTNING.
THIS WILL CONTINUE THROUGH TUESDAY EVENING. DETERMINING HOW FAR
NORTH THUNDERSTORMS WILL MIGRATE THIS AFTERNOON THROUGH WEDNESDAY
WILL CONTINUE TO BE A CHALLENGE. SCATTERED THUNDERSTORMS ARE
EXPECTED ACROSS OR611 AND FOR THE SOUTHERN PORTIONS OF OR 610 AND
640. LIGHTNING FROM PREVIOUS STORMS HAS BEEN IN THE LAL 4
CATEGORY...SO CWR`S AND LALS HAVE BEEN BUMPED UP FOR THESE AREAS
TODAY. THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY ACROSS CENTRAL AND EASTERN OREGON LATE THURSDAY THROUGH
NEXT WEEKEND WHEN THE LOW OPENS AND DEVELOPS A BROAD TROUGH WEST OF
THE ROCKIES. THE GOOD NEWS IS THAT STORMS MAY BRING HEAVY
RAIN...ESPECIALLY LATE IN THE WEEK. WEBER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  98  63  97 /   0   0   0   0
ALW  70  99  69  97 /   0   0   0   0
PSC  66 101  66 101 /   0   0   0   0
YKM  65  98  66  99 /   0   0   0   0
HRI  65 101  65 101 /   0   0   0   0
ELN  64  99  63 101 /   0  10  10   0
RDM  58  94  54  92 /  30  20  20  10
LGD  56  93  52  90 /   0  10  10  10
GCD  60  96  57  96 /  10  20  20  20
DLS  69  99  68  99 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 9 PM PDT TUESDAY FOR ORZ610-611-640.

WA...NONE.
&&

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

$$

94


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.