070
FXUS66 KPDT 280517
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1017 PM PDT MON JUL 27 2026
KEY MESSAGES
- DIURNAL BREEZES EXPECTED MUCH OF THIS WEEK, WITH TUESDAY AND
SATURDAY BEING THE WINDIEST DAYS.
- QUIET WEATHER FOR THE UPCOMING WEEK.
DISCUSSION
A 549 DM 500 MB LOW OFF THE NRN BC COAST WITH AN ATTENDANT
TROUGH WAS POSITIONED OFF THE NRN BC COAST TODAY. AN ATTENDANT
TROUGH WILL SWING EASTWARD OUT OF THE NE PAC OCEAN INTO THE PAC
NW AND INTERIOR NW OVER THE NEXT 24 TO 48 HOURS. SOUTHWEST FLOW
ALOFT WILL OVERRUN A HIGH PRESSURE AT THE BOUNDARY LAYER THAT
WILL ALLOW FOR SOME DIURNALLY DRIVEN GAP WINDS, ESPECIALLY
THOUGH THE COLUMBIA RIVER GORGE HOWEVER MOST THE THE AREA WILL
SEE GUSTS CAPPED IN THE 15 TO 20 MPH RANGE OVER THE NEXT COUPLE
OF DAYS. TRENDS FOR A COMPACT SHORTWAVE RIDING THROUGH THE
BASE OF THE TROUGH THURSDAY INTO EARLY FRIDAY ARE LEADING TO
SOME LOW THUNDER PROBABILITIES ACROSS THE HIGHER TERRAIN ON
THURSDAY (MOSTLY ABOUT A 10% CHANCE OR LESS BASED ON NBM CONUS
ENSEMBLE MEMBERS). HEAT RISK WILL REMAIN THE MINOR CATEGORY
THOUGH MOST OF THE PERIOD, ALTHOUGH BY FRIDAY WARMER
TEMPERATURES IN THE EASTERN MOUNTAINS FOOTHILLS AND NORTH
CENTRAL OREGON APPEAR TO DRIVE THE HEATRISK INTO THE MODERATE
CATEGORY, WHICH CAN AFFECT THOSE SENSITIVE TO HEAT WITHOUT
COOLING OR HYDRATION AS WELL AS SOME HEALTH SYSTEMS AND
INDUSTRIES. THE AREA OF SMOKE WILL CONTINUE TO LINGER DOWNWIND
OF ONGOING FIRES FROM CENTRAL OREGON ACROSS THE EASTERN
MOUNTAINS. AIR QUALITY ADVISORIES HAVE BEEN ISSUES IN ACCORDANCE
WITH DEQ ALERTS THOUGH THE MIDDAY WEDNESDAY AS RECENT AQIS WERE
INT EH 100 TO 171 RANGE. BY SATURDAY THE UPPER LOW AND MEAN
TOUGH OVER THE BC COAST IS SHOWN TO ACCELERATE INLAND THOUGH
SATURDAY NIGHT, FLATTENING (ZONAL) OUT AND INCREASING THE HEIGHT
GRADIENT ALOFT WITH A FRONTAL PASSAGE AND SIGNIFICANT INCREASE
IN WESTERLY SURFACE WINDS IMPACTING FIRE RISK LEVELS
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
VFR CONDITIONS TO
PREVAIL THROUGH THE PERIOD. LOW CONFIDENCE IN CONSISTENT SMOKE
IMPACTS AT SITES, BUT HAVE LEFT 6SM HZ AT SITES PDT/PSC THROUGH
THE OVERNIGHT HOURS. WINDS WILL INCREASE TO AROUND 12-20KTS WITH
GUSTS 20-30KTS ACROSS ALL SITES TOMORROW AFTERNOON, WITH WINDS
EXPECTED TO WEAKEN MID TO LATE EVENING TOMORROW. OTHERWISE,
WINDS WILL BE REMAIN LIGHT. LAWHORN/82
FIRE WEATHER
LOW RH IS THE CRITICAL ELEMENT RELATIVE TO FIRE WEATHER, BUT
WINDS WILL NOT COMBINE AT LEVELS NEEDED TO REACH A RED FLAG
CRITERIA ON ANYTHING MORE THAN A LATE AFTERNOON AND VERY SPOTTY
NATURE THIS WEEK. A MORE SIGNIFICANT IMPACT TO THE FIRE RISK
LEVELS WILL ARRIVE SATURDAY AS A FRONTAL PASSAGE INCREASES WIND
SPEEDS ON A WIDESPREAD BASIS.
PRELIMINARY POINT TEMPS/POPS
PDT 57 87 54 87 / 0 0 0 0
ALW 63 90 60 89 / 0 0 0 0
PSC 61 92 57 90 / 0 0 0 0
YKM 59 89 56 89 / 0 0 0 0
HRI 61 90 57 90 / 0 0 0 0
ELN 56 81 52 85 / 0 0 0 0
RDM 50 87 48 88 / 0 0 0 0
LGD 56 90 54 91 / 0 0 0 0
GCD 54 92 54 94 / 0 0 0 0
DLS 62 83 59 88 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...AIR QUALITY ALERT UNTIL NOON PDT WEDNESDAY FOR ORZ041-044-049-
050-502-503-505>511.
DISCUSSION...71
AVIATION...82
FIRE WEATHER...71
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