404
FXUS66 KMFR 021111
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
411 AM PDT WED SEP 2 2026
KEY MESSAGES
* AN UNUSUALLY STRONG SYSTEM FOR EARLY SEPTEMBER WILL BRING
WETTING RAIN TO THE REGION WITH GUSTY WINDS ALONG THE COAST
WEDNESDAY.
* ROCK SLIDES ARE POSSIBLE ALONG HIGHWAYS 42, 138 AND 38.
* TEMPERATURES WILL BE 15 TO 25 DEGREES COOLER THAN NORMAL
WEDNESDAY AND THURSDAY.
* COOLER CONDITIONS WITH SHOWER CHANCES PERSISTING INTO EARLY NEXT
WEEK.
* SCATTERED THUNDERSTORMS EXPECTED ON THURSDAY.
DISCUSSION
SHOWERS ARE ONGOING THIS MORNING AS A DEEP TROUGH APPROACHES THE
OREGON COAST. CLOUDS ARE WIDESPREAD WITH VERY LITTLE CLEARING.
FROST LOOKS UNLIKELY TONIGHT AS TEMPERATURES HOVER IN THE MID
40'S AND ACTUALLY INCREASED IN A FEW SPOTS OVER THE LAST FEW HOURS.
LIKE WE'VE MENTIONED THE LAST FEW NIGHTS, THE EXTREME FORECAST
INDEX(EFI) CONTINUES TO HINT THIS IS AN UNUSUALLY STRONG EVENT
FOR EARLY SEPTEMBER. EFI VALUES ARE BETWEEN 0.9 TO 1 FOR WIND
GUSTS, TEMPERATURES AND THE QPF TODAY. THE COAST AND COASTAL
MOUNTAINS ARE AN AREA FOR CONCERN TODAY WITH RESPECT TO WIND
GUSTS. THE NBM MAX WIND GUST OVER 24 HOURS IS SHOWING 50KTS OVER
THE COASTAL TERRAIN. THE EFI PRODUCT ALSO SHOWS SHIFT OF TAILS OF
1 AND WINDS ARE ALREADY EXCEEDING FORECAST THERE. IN ANY CASE,
POCKETS OF POWER OUTAGES ARE POSSIBLE AS THIS FRONT APPROACHES THE
COAST WITH GUSTS TO 50 MPH A REASONABLE BAD CASE SCENARIO.
WITH REGARDS TO PRECIPITATION, RAIN WILL BECOME MORE WIDESPREAD
THIS MORNING INTO THE AFTERNOON HOURS. THE ECMWF ENSEMBLE IS
PREDICTING SOME HEAVY RAIN AROUND THE BROOKINGS AREA WITH SOME
LOCATIONS SEEING UP TO 2 INCHES OF RAIN BETWEEN 11AM AND 5PM THIS
AFTERNOON. THAT IS A HEFTY AMOUNT OF QPF IN 6 HOURS FOR OUR
WETTER WINTER STORMS. OTHERWISE, THE PRECIPITATION WILL MOVE
EASTWARDS BY THE EVENING HOURS WITH LOCATIONS EAST OF THE CASCADES
SEEING SOME RAIN.
BY THURSDAY, THE COLD FRONT WILL BE IN SOUTH EASTERN OREGON AND
WEAKENING. IN ADDITION, THE TROUGH AND SURFACE LOW WILL PUSH INTO
THE OREGON COAST BY THURSDAY AFTERNOON. ENSEMBLES ARE SPLIT ON
HOW MUCH RAIN WILL FALL ALONG THE WEAKENING COLD FRONT IN LAKE
COUNTY WITH SOME SHOWING OVER AN INCH WHILE OTHERS ARE
SIGNIFICANTLY DRIER. IN ADDITION, SHOWERS AND A FEW THUNDERSTORMS
WILL PROBABLY DEVELOP OVER SOUTHERN OREGON AND NORTHERN CALIFORNIA
THURSDAY AFTERNOON. THE HRRR BUFKIT SOUNDINGS SHOW ~100J/KG OF
SURFACE BASED CONVECTIVE AVAILABLE POTENTIAL ENERGY(SBCAPE) AT A
FEW SITES THURSDAY AFTERNOON. THE SBCAPE IS TALL AN SKINNY, SO
WE'RE NOT EXPECTING ANY STRONG STORMS. HOWEVER, SOME LIGHTNING IS
NOT OUT OF THE QUESTION AS THE CAPE TOUCHES THE -10C TO -15C LEVEL.
THE NBM TSTORM PROBABILITY IS ALSO 15-20% ACROSS THE MAJORITY OF
THE AREA.
ALTHOUGH THE AIR IS UNUSUALLY COLD WITH THIS SYSTEM, OUR
OVERNIGHT LOW TEMPERATURE FORECAST WITH THE NBM/NDFD IS LIKELY TOO
COLD, ESPECIALLY IN SOME OF THE VALLEYS EAST OF THE CASCADES.
LINGERING CLOUD COVER FROM A LOW BEING OVERHEAD SHOULD KEEP
TEMPERATURES FROM DROPPING TOO LOW. FOR EXAMPLE, THE NBM HAS 28
FOR A LOW AT KLMT WITH A 30% PROBABILITY OF PRECIPITATION IN THE
REGION AND A 6400 FOOT SNOW LEVEL THURSDAY NIGHT. OTHER
DETERMINISTIC GUIDANCE HAS LOWS IN THE MID TO UPPER 30'S AT KLMT.
LASTLY, THIS UPPER LEVEL LOW WILL HANG AROUND UNTIL MONDAY.
ALL THE ECMWF ENSEMBLE MEMBERS SHOW THAT WITH THE EXACT LOCATION
OF THE LOW VARYING 200-400 MILES. SHOWER INTENSITY AND LOCATION
STILL VARIES SOME FROM FRIDAY INTO MONDAY, ALTHOUGH WE FEEL
CONFIDENT POPS WILL REMAIN IN THE FORECAST WITHIN OUR WARNING
AREA.
-SMITH
AVIATION (06Z TAFS)
AHEAD OF AN INCOMING FRONT, EXPECT LOW AND MID LEVEL CLOUDS TO
INCREASE TONIGHT WITH INCREASING RAIN CHANCES TOMORROW. MVFR
CONDITIONS ARE LIKELY TO BECOME WIDESPREAD ALONG THE COAST TONIGHT
WITH MVFR AND LOCAL IFR CONDITIONS WEDNESDAY. INLAND, AREAS OF
MVFR WILL DEVELOP WITH RAIN WEDNESDAY MORNING, ESPECIALLY FROM THE
CASCADES WEST, BECOMING WIDESPREAD WEDNESDAY AFTERNOON AND
WEDNESDAY EVENING. GUSTY WINDS ARE EXPECTED ALONG THE COAST
BEGINNING WEDNESDAY MORNING AND FOR MANY INLAND AREAS WEDNESDAY
AFTERNOON AND EVENING. AREAS OF LOW LEVEL WIND SHEAR ARE EXPECTED
ALONG THE COAST IN THE MORNING AND EARLY AFTERNOON.
MARINE...UPDATED 200 AM PDT WEDNESDAY, SEPTEMBER 2, 2026
SOUTH
WINDS WILL SOON INCREASE AHEAD OF AN APPROACHING COLD FRONT.
CONDITIONS WILL BE HAZARDOUS TO SMALLER CRAFTS FOR MOST OF THIS
MORNING BEFORE GALE FORCE WINDS ARE EXPECTED THIS AFTERNOON AS
THE COLD FRONT APPROACHES WITH GUSTS AROUND 45 KNOTS. ONCE THE
FRONT MOVES THROUGH, A WESTERLY SWELL AROUND 10 FEET AT 10 SECONDS
WILL MOVE INTO THE WATERS THURSDAY AFTERNOON.
CONDITIONS IMPROVE FRIDAY, AND REMAIN RELATIVELY CALM THROUGH THE
WEEKEND AND POTENTIALLY INTO EARLY NEXT WEEK.
MFR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY UNTIL 8 AM PDT THIS MORNING FOR ORZ029>031.
CA...FROST ADVISORY UNTIL 8 AM PDT THIS MORNING FOR CAZ085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM PDT EARLY
THIS MORNING FOR PZZ350-356-370-376.
GALE WARNING UNTIL 7 PM PDT THIS EVENING FOR PZZ350-356-370-376.
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