539
FXUS66 KPDT 011827
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1127 AM PDT TUE APR 1 2025
MORNING AND AVIATION UPDATE
MORNING UPDATE
RADAR AND CAMS SHOWED LIGHT SNOW FALL IN THE
BEND/REDMOND AREA. DECIDED TO INCREASE POP CHANCES THERE FOR THE
MORNING HOURS ALONG WITH EXTENDING PRECIPITATION JUST ABOVE THE
TRI-CITIES AREA. SATELLITE SHOWS A BREAK IN THE CENTRAL REGION OF
THE CWA. CAPE VALUES ARE AROUND 150-250 J/KG AT THIS MOMENT AND
WILL CONTINUE TO MONITOR VALUES FOR ANY POTENTIONAL ISOLATED
THUNDERSTORM ACTIVITY IN THE AFTERNOON.
AVIATION...18Z TAFS
LATEST AVIATION CONCERNS REVOLVE AROUND A)
ONGOING SNOW SHOWERS IN CENTRAL OR, B) AFTERNOON RAIN SHOWER CHANCES
WITH A LOW CHANCE OF THUNDER THIS AFTERNOON, AND C) POSSIBLY SUB-VFR
LATE TONIGHT. LATEST RADAR AND SATELLITE DEPICTS SOME ISOLATED LIGHT
RAIN SHOWERS ACROSS SOUTH CENTRAL WA AND AREA OF LIGHT SNOW ACROSS
KBDN. BOTH SHOULD LESSEN IN COVERAGE AND DIMINISH BETWEEN NOW AND 20
UTC BEFORE RENEWED ISOLATED-WIDELY SCATTERED SHOWERS DEVELOP THIS
AFTERNOON. LATEST HREF GUIDANCE AND MARGINAL INSTABILITY SUPPORT A
RISK FOR THUNDER (10-30%) OUTSIDE OUR TAF TERMINALS ACROSS THE
EASTERN MOUNTAINS. OTHERWISE, THESE SHOWER CHANCES WILL DIMINISH IN
THE EVENING WITH LOSS OF DAYTIME HEATING. THE OTHER CONCERN IS
POTENTIAL FOR STRATUS TO BUILD INTO CENTRAL OR OVERNIGHT-EARLY
MORNING TOMORROW WITH SUB-VFR CEILINGS LOOKING MORE LIKELY THAN
NOT.
PREV DISCUSSION
/ISSUED 341 AM PDT TUE APR 1 2025/
SHORT TERM...TODAY THROUGH THURSDAY...CURRENTLY, SATELLITE AND
RADAR IMAGERY SHOW SHOWERS APPROACHING THE UPPER PART OF THE LOWER
COLUMBIA BASIN AND THE CREST OF THE OR CASCADES. CLOUD COVERAGE
INCREASES AT THOSE AFOREMENTIONED AREAS DUE TO THE LOW CIRCULATIONS
FROM THE ONGOING UPPER TROUGH. LOW TEMPERATURES WILL SLIGHTLY RISE
FOR THOSE AREAS ALSO, THANKS TO CLOUDS ASSISTING IN KEEPING THEM
WARM.
WITH THE TROUGH MOVING SOUTHEASTWARD, SHOWER ACTIVITY WILL CONTINUE
FOR THE UPPER PARTS OF THE LOWER COLUMBIA BASIN WITH MOUNTAIN SNOW
OVER THE OR CASCADES. SHOWERS WILL THEN BECOME WIDESPREAD BY LATER
THIS MORNING INCLUDING MOUNTAIN SNOW OVER THE BLUES AND WA/OR
CASCADES UP TO AN INCH OR LESS. ALONG WITH THAT, ISOLATED THUNDER
COULD DEVELOP OVER THE BLUES, CENTRAL OR, AND SIMCOE HIGHLANDS
THROUGH THIS EARLY EVENING. BUT, CHANCES FOR SEVERITY ARE LOW DUE TO
WEAK INSTABILITY (CAPE UNDER 500 J/KG). AS NORTHWEST FLOW INCREASES,
LOCALLY BREEZY CONDITIONS WILL OCCUR FOR KITTITAS VALLEY AND
PORTIONS OF THE NORTHERN BLUES THROUGH THIS MORNING. AFTERNOON INTO
TONIGHT, GUSTS DEVELOP AT 25-35 MPH ACROSS THE CASCADES AND THEN THE
GORGE AND NORTH CENTRAL OR.
TOMORROW, THE LOWLANDS WILL BE MAINLY DRY WITH LINGERING MOUNTAIN
SNOW AS THE UPPER RIDGE GRADUALLY APPROACHES. THROUGH EARLY EVENING,
THE FOOTHILLS OF THE BLUES, KITTITAS VALLEY, CASCADES AND NORTHERN
BLUES WILL REMAIN GUSTING AT 25-35 MPH DUE TO THE WESTERLY FLOW. BY
TOMORROW NIGHT, WIND GUSTS SHOULD BEGIN DECREASING TO BREEZY FOR
THOSE AFOREMENTIONED AREAS. ANY PRECIP ACTIVITY WILL START TO CEASE
THROUGH THURSDAY WITH THE RIDGE OVER THE FORECAST AREA AT THAT TIME.
HOWEVER, BREEZY WINDS MAY CONTINUE WIDESPREAD THROUGH THURSDAY LATE
EVENING BEFORE DECREASING AT NIGHT. FEASTER/97
LONG TERM...FRIDAY THROUGH TUESDAY...A WARMING TREND WILL INITIATE
FRIDAY AS A COLD, N/NW FLOW PATTERN TRANSITIONS TO RIDGING, ALLOWING
HIGH TEMPERATURES TO RISE TO SLIGHTLY ABOVE AVERAGE VALUES, MORE
INDICATIVE OF EARLY SPRING. A QUICK-MOVING SW WAVE WILL THEN BRING A
ROUND OF PRECIP TO THE FORECAST AREA LATE SUNDAY INTO MONDAY, BEFORE
RIDGING TAKES OVER YET AGAIN. SENSIBLE WEATHER IMPACTS ARE THUS
LIMITED FOR THE FORECAST PERIOD.
ENSEMBLE GUIDANCE IS GENERALLY IN GOOD AGREEMENT ON THE SYNOPTIC
PATTERN THROUGH THE MIDDLE OF NEXT WEEK. THE ONLY REAL FEATURE OF
NOTE IS THE AFOREMENTIONED SW WAVE LATE NEXT WEEKEND, ALTHOUGH THUS
FAR GUIDANCE IS NOT REALLY KEYING IN ON A PARTICULARLY WET SYSTEM.
AND WITH SNOW LEVELS RISING TO ABOVE 6000 FT WITH THE PRECEDING
RIDGING, EVEN THE MOUNTAINS ARE EXPECTED TO BE SPARED OF ANY
MEANINGFUL IMPACTS. LOCALLY GUSTY CONDITIONS ARE EXPECTED TO RESULT
FROM THIS TRANSITION BETWEEN RIDGING AND UPPER-LEVEL WAVES, BUT
PRESSURE GRADIENT GUIDANCE THUS FAR DOES NOT SUGGEST ANYTHING
HEADLINE-WORTHY.
OVERALL, GENERALLY QUIET CONDITIONS OUTSIDE OF PRECIP LATE SUNDAY
INTO MONDAY. EXPECT EVEN WARMER TEMPS BEYOND THE LONG TERM SHOULD
ENSEMBLES VERIFY AND RIDGING BUILDS BACK IN. EVANS/74
PRELIMINARY POINT TEMPS/POPS
PDT 54 37 55 35 / 20 30 10 0
ALW 53 38 53 36 / 20 30 20 10
PSC 59 35 60 35 / 20 20 0 0
YKM 58 32 57 33 / 20 10 0 0
HRI 58 37 58 35 / 20 30 0 0
ELN 54 34 55 34 / 20 0 0 0
RDM 51 28 50 26 / 30 20 0 0
LGD 50 32 48 28 / 30 30 20 10
GCD 47 31 46 27 / 40 60 20 10
DLS 57 39 57 36 / 20 20 10 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...97
LONG TERM....74
AVIATION...80
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