Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 031651 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
951 AM PDT TUE MAY 3 2016

UPDATED AVIATION DISCUSSION

.SHORT TERM...FORECAST IS ON TRACK AND ONLY MINOR TWEAKS WERE MADE
TO DECREASE CLOUD COVER IN A FEW OF OUR ZONES THIS MORNING AND TO
INCREASE POPS AN ADDITIONAL 5-10 PCT FOR AREAS NEAR THE CASCADE
RANGE THIS AFTERNOON AND EVENING. AN OMEGA BLOCKING PATTERN HAS
SET UP FROM THE EASTERN PACIFIC AND ACROSS THE U.S. AN ELONGATED
HIGH PRESSURE RIDGE HAS SHIFTED EASTWARD...AND THE UPPER FLOW HAS
BACKED TO THE SOUTH OVER THE FORECAST AREA. MOISTURE ON THE
BACKSIDE OF THE RIDGE WILL GRADUALLY MAKE ITS WAY EASTWARD AND
BRING SCATTERED SHOWERS ALONG THE CASCADE RANGE AND AS FAR EAST
AS BICKLETON...CONDON AND PAULINA THIS AFTERNOON. THE HRRR LOOKS
REASONABLE SHOWING SHOWERS DEVELOPING AROUND 1400 AND INCREASING
IN COVERAGE BY 1800. SURFACE-BASED CAPES ARE AROUND 300 J/KG AND
LI`S BETWEEN 0 TO -2...SO THERE WILL BE A FEW THUNDERSTORMS IN
THESE AREAS AS WELL. THE BULK WIND SHEAR IS MINIMAL TODAY...SO
HAVING A SUSTAINED UPDRAFT FOR STRONG THUNDERSTORMS IS NOT LIKELY
TO HAPPEN.

ANOTHER WARM DAY IN THE FORECAST FOR ALL AREAS...WITH NEAR RECORD
HIGH TEMPERATURES OVER THE LOWER COLUMBIA BASIN AND THE YAKIMA
VALLEY. WISTER

&&

.AVIATION...18Z TAFS...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24
HRS. INCREASING MID AND HIGH CLOUDS ESPECIALLY WEST. THERE WILL BE
SOME CUMULUS BUILDUPS NEAR KRDM...KBDN... KDLS...AND KYKM AFTER 21Z
WITH A FEW SHRA AND POSSIBLE TSRA. WINDS WILL BE 5-15KT AND A LITTLE
GUSTY AT KDLS THIS AFTERNOON AND EARLY EVENING. 76

&&

.PREV DISCUSSION... /ISSUED 300 AM PDT TUE MAY 3 2016/

SHORT TERM...AS THE LOW CONTINUES TO TRACK SOUTHEAST TOWARD
SOUTHERN NEVADA ON WEDNESDAY AND THURSDAY...COOLER AIR WILL
INTRUDE. STILL...THERE WILL BE MOISTURE AND INSTABILITY SPUN UP
OVER THE AREA FOR ENHANCED THUNDERSTORM COVERAGE AS WELL AS
INCREASED CHANCES OF WETTING RAIN. THUNDERSTORMS MAY EVEN CONTINUE
OVERNIGHT AS THERE MAY BE SOME UPPER LEVEL FORCING ALONG WITH
MODERATE 500-300MB LAPSE RATES. WILL KEEP AN EYE ON THIS BUT FOR
NOW JUST CONTINUING SHOWERS OVERNIGHT WEDNESDAY NIGHT.

BY THURSDAY THE NORTHEAST MOUNTAINS SHOULD HAVE ENOUGH RESIDUAL LOW
LEVEL MOISTURE AND FAVORABLE UPSLOPE FLOW FROM THE SOUTHEAST TO
CONTINUE THUNDERSTORMS. 500MB DIFLUENT FLOW ALOFT COULD ALSO AID IN
AIR ACCELERATING UPWARD.  SO FOR THIS AREA...HAVE DECIDED TO GO WITH
CHANCE THUNDERSTORMS...AND A SLIGHT CHANCE WILL CONTINUE FOR THE
REST OF THE NORTHWESTERN CWA. ALTHOUGH TEMPERATURES WILL BE COOLER
BY A FEW DEGREES ON WEDNESDAY AND THURSDAY...THEY WILL STILL BE
NEAR TO SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. WEBER

LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...A LARGE UPPER LEVEL
LOW WILL MOVE FROM CALIFORNIA ACROSS THE GREAT BASIN INTO THE
CENTRAL ROCKIES THROUGH THE FORECAST PERIOD. ON THURSDAY EVENING
THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS WITH ACTIVITY
DIMINISHING OVERNIGHT. ON FRIDAY WITH THE UPPER LOW OVER SRN
CALIFORNIA EXPECT THE THREAT FOR SHOWERS AND THUNDERSTORMS TO BE
CONFINED TO THE EASTERN THIRD OF THE FORECAST AREA. JUST THE
SOUTHERN FRINGES OF THE FORECAST AREA MAY SEE A SHOWER OR STORM ON
SATURDAY. SUNDAY THROUGH TUESDAY LOOK DRY AS NWLY FLOW DEVELOPS OVER
THE AREA. THERE WILL BE A COUPLE OF WINDY PERIODS. THE FIRST WILL BE
FRIDAY EVENING WITH GUSTY N-NELY WINDS AND THE SECOND SUNDAY EVENING
IN THE CASCADE GAPS WITH STRONG WESTERLY WINDS. TEMPERATURES WILL BE
WARMING PEAKING SUNDAY WITH HIGHS IN THE UPPER 80S COLUMBIA BASIN
THEN COOLING MONDAY AND TUESDAY TO MID 70S TO LOWER 80S LOWER
ELEVATIONS. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  86  51  77  51 /   0  10  20  50
ALW  86  54  80  53 /   0  10  20  50
PSC  87  55  82  56 /   0  10  20  40
YKM  84  54  81  51 /  10  30  30  30
HRI  86  54  79  53 /   0  10  20  40
ELN  82  52  78  49 /  10  30  30  40
RDM  75  45  69  43 /  30  50  60  60
LGD  80  47  79  48 /   0  10  30  40
GCD  79  46  77  47 /  10  10  50  60
DLS  82  55  76  52 /  20  40  30  40

&&

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

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

$$

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