592
FXUS66 KMFR 052025
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
125 PM PDT SUN JUL 5 2026
DISCUSSION
HIGH CLOUDS HAVE STREAMED ACROSS THE AREA FROM THE
SOUTH TODAY, AND SOME MORE MIDLEVEL CLOUDS ARE JUST BEGINNING TO
ENTER OUR NORTHERN CALIFORNIA ZONES. THESE ILLUSTRATE THE MOISTURE
THAT IS ACCOMPANYING A SHORTWAVE AS IT ENTERS THE REGION, AND
WILL EVENTUALLY RESULT IN INSTABILITY AND CONVECTION LATER THIS
AFTERNOON AND EVENING. THIS CONVECTION WILL BE CONCENTRATED ALONG
AND EAST OF THE CASCADES, ALTHOUGH WE CANNOT RULE OUT AN ISOLATED
STORM OR TWO OVER THE KLAMATHS AND SISKIYOUS. MOISTURE IS ON THE
LOW SIDE, SO WHILE SOME PRECIPITATION IS POSSIBLE WITHIN THE CORES
OF ANY STORMS TODAY, SOME COULD BE DRY. THE LATEST SPC HREF HAS A
BULLSEYE RIGHT OVER LAKE COUNTY WITH A 40 TO 50 PERCENT CHANCE OF
LIGHTNING WITHIN 20KM OF A POINT. WIND SHEAR IS ABOUT 20 KNOTS
OUT OF THE SOUTH WEST. FORECAST SOUNDINGS SHOW THE TYPICAL
INVERTED V SOUNDINGS IN SOUTHERN OREGON WITH MIXING UP 4KM ABOVE
GROUND LEVEL, SO GUSTY OUTFLOW WINDS TO 40 KNOTS SEEM PROBABLE IN
THESE THUNDERSTORMS.
THUNDERSTORMS COULD CONTINUE WELL INTO THE EVENING AND EARLY
OVERNIGHT HOURS, ALTHOUGH THEY SHOULD START TO DIE AROUND 8Z
MONDAY (SHORTLY AFTER MIDNIGHT PDT). THE UPPER LEVEL LOW WEAKENS
AND ADDITIONAL VORTICITY FROM THAT LOW EVENTUALLY MOVES IN BY
MONDAY. WITH AMPLE HEATING AND INCREASED MOISTURE, THUNDERSTORMS
REMAIN IN THE FORECAST EAST OF THE CASCADES ON MONDAY AFTERNOON,
AND ARE MUCH MORE LIKELY TO PRODUCE PRECIPITATION AT THE SURFACE.
AGAIN, PROBABILITIES FOR CLOUD TO GROUND LIGHTNING ARE AROUND 50
TO 70 PERCENT WITHIN LAKE COUNTY, CONCENTRATED A BIT FARTHER NORTH
THAN TODAY. CONVECTIVE PROBABILITIES DROP OFF SIGNIFICANTLY
FARTHER TO THE WEST AND SOUTH, AND WILL END EARLIER IN THE DAY
THAN SUNDAY AS THE IMPULSE PUSHES OFF TO THE NORTHEAST BY LATE
AFTERNOON.
BY TUESDAY EVENING, A 500 MB TROUGH WILL PUSH INTO THE PACIFIC
NORTHWEST. THIS WILL BRING SOME STRONGER NORTHWEST FLOW TO THE
REGION, AND A MARINE PUSH INTO THE COASTAL VALLEYS AND THE UMPQUA
BASIN. SOME DATA SHOWS A DISSIPATING COLD FRONT MOVING CLOSER TO
THE COAST. IN ANY CASE, TEMPERATURES SHOULD TREND A FEW DEGREES
COOLER ON WEDNESDAY WITH MEDFORD TRENDING 5 DEGREES COOLER BASED
ON THE LATEST FORECAST. WITH THIS UPPER LEVEL LOW PUSHING INLAND,
ISOLATED SHOWERS OR THUNDERSTORMS CAN'T BE RULED OUT ON TUESDAY
EVENING. THE ECMWF ENSEMBLE SHOWS SPOTTY QPF AROUND MOST OF
CENTRAL OREGON, WHICH COULD CLIP NORTHERN LAKE OR KLAMATH COUNTIES
BEFORE CONDITIONS DRY WEDNESDAY. ADDITIONALLY, WE ARE LIKELY TO
SEE ENHANCED AFTERNOON AND EVENING WINDS TUESDAY AND WEDNESDAY AS
THE DYING FRONT PASSES, ESPECIALLY OVER THE EAST SIDE.
AFTER RATHER MUNDANE, TYPICAL SUMMER CONDITIONS THURSDAY INTO
FRIDAY, ANOTHER TROUGH AND POTENTIAL FRONT ARRIVES OVER THE
WEEKEND. THERE IS A LOT OF UNCERTAINTY REGARDING THIS SYSTEM, AND
WHILE IT WILL MOST LIKELY BE DRY, WE SHOULD SEE ANOTHER DAY OR TWO
OF INCREASED AFTERNOON WINDS.
AVIATION...05/18Z TAFS
VFR LEVELS ARE PRESENT ACROSS MOST OF
NORTHERN CALIFORNIA AND SOUTHERN OREGON LATE THIS MORNING, WITH
LIFR LEVELS PERSISTING AT BROOKINGS AND GUSTY WINDS AT THE NORTH
BEND TERMINAL. INLAND AREAS WILL STAY AT VFR THROUGH THE TAF
PERIOD, WITH ONLY HIGH CLOUDS AND DIURNAL BREEZES IN THE FORECAST
AT AREA TERMINALS. MARINE STRATUS LOOKS TO RETURN TO NORTH BEND
THIS AFTERNOON, BRINGING IFR CEILINGS AND CHANCES FOR LOWER
VISIBILITIES THAT WILL CONTINUE INTO MONDAY MORNING.
THUNDERSTORM CHANCES ARE PRESENT IN LAKE AND EASTERN KLAMATH
COUNTIES THIS AFTERNOON AND EVENING, BUT GUIDANCE KEEPS ACTIVITY
FROM THE KLAMATH FALLS TERMINAL. THERE'S A NONZERO CHANCE OF A
STRAY STORM NEARBY, BUT REPEATED ACTIVITY IS NOT EXPECTED. -TAD
MARINE...UPDATED 200 PM PDT SUNDAY, JULY 5, 2026
GUSTY
NORTHERLY WINDS ARE EXPECTED TO EASE THIS AFTERNOON AND INTO THE
WEEK AHEAD. HOWEVER, THESE WINDS ARE STILL STRONG ENOUGH TO
SUPPORT VERY STEEP SEAS SOUTH OF CAPE BLANCO AND BEYOND 5 NM FROM
SHORE WHILE STEEP SEAS PERSIST IN ALL OTHER AREA WATERS THROUGH
TONIGHT. WHILE WINDS CONTINUE TO DECREASE ON MONDAY, A SLIGHT RISE
IN WESTERLY SWELL WILL SUPPORT STEEP SEAS CONTINUING IN ALL
WATERS THROUGH THE DAY. STEEP SEAS LOOK TO BE LIMITED TO WATERS
SOUTH OF CAPE BLANCO FOR TUESDAY THROUGH WEDNESDAY MORNING.
CURRENTLY, NORTHERLY WINDS START TO INCREASE ON WEDNESDAY
MORNING. THIS MAY BRING ADDITIONAL AREAS OF UNSETTLED SEAS TO
AREA WATERS INTO THE END OF THE WEEK. -TAD
FIRE WEATHER...UPDATED 1200 PM PDT SUNDAY, JULY 5, 2026
WARM
AND DRY CONDITIONS WILL CONTINUE FOR THE NEXT WEEK, WITH TYPICAL
AFTERNOON BREEZES EACH DAY. THERE WILL BE A FEW PERIODS OF
CONCERN: THE FIRST THIS AFTERNOON AND AGAIN TOMORROW EAST OF THE
CASCADES, WHERE ABUNDANT LIGHTNING IS EXPECTED, AND THE SECOND
BEING TWO DRY FRONTAL PASSAGES THAT WILL BRING GUSTY WINDS AND
LOW RH TO PORTIONS OF THE AREA.
THERE IS A CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EAST OF
THE CASCADES, FOCUSED MAINLY OVER CENTRAL AND SOUTHERN LAKE
COUNTY AND EASTERN KLAMATH COUNTY. SOME ISOLATED STORMS ARE
POSSIBLE ELSEWHERE EAST OF THE CASCADES, AND OVER NORTHERN
CALIFORNIA, INCLUDING THE KLAMATHS, SISKIYOUS, AND WARNERS. THERE
IS LIMITED MOISTURE TODAY, SO WHILE RAIN IS EXPECTED WITHIN THE
CORES OF MOST OF THESE THUNDERSTORMS, A FEW MORE HIGH BASED
STORMS, OR THOSE ALONG THE PERIPHERY OF THE DRIER AIR, COULD
PRODUCE VERY LITTLE OR NO RAIN AT THE SURFACE. ALONG WITH PLENTY
OF LIGHTNING, GUSTY AND ERRATIC WINDS OF UP TO 45 MPH WILL BE A
CONCERN FOR ANY STORMS THAT DEVELOP (ESPECIALLY THE DRIER ONES).
ALSO, THERE IS A POSSIBILITY THAT SOME OF THESE SHOWERS AND AN
ISOLATED THUNDERSTORM OR TWO LINGER ON INTO SUNDAY NIGHT/EARLY
MONDAY MORNING OVER LAKE COUNTY.
ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED MONDAY AFTERNOON, THIS
TIME FOCUSED A BIT FARTHER NORTH OVER NORTHERN LAKE AND KLAMATH
COUNTIES. MORE MOISTURE WILL BE AVAILABLE THEN, SO DRY
THUNDERSTORMS ARE LESS LIKELY, BUT STILL POSSIBLE. ALSO, WE CANNOT
RULE OUT AN ISOLATED STORM OR TWO OVER THE REST OF THE EAST SIDE
AND NORTHERN CALIFORNIA. AGAIN, LIGHTNING AND GUSTY OUTFLOW WINDS
WILL BE THE PRIMARY CONCERNS. A RED FLAG WARNING HAS BEEN ISSUED
FOR BOTH AFTERNOONS, AND DETAILS CAN BE FOUND AT PDXRFWMFR.
OTHERWISE, HIGH TEMPERATURES REMAIN AROUND 5 TO 10 DEGREES ABOVE
NORMAL, AND AFTERNOON BREEZES REMAIN TYPICAL TO SLIGHTLY ENHANCED
DURING THE NEXT WEEK. THIS WILL RESULT IN VERY DRY CONDITIONS,
GENERALLY JUST SHY OF CRITICAL WIND AND HUMIDITY THRESHOLDS,
ESPECIALLY TUESDAY AND WEDNESDAY, AND POTENTIALLY AGAIN THIS
WEEKEND, AS DRY COLD FRONTS PASS THROUGH OR JUST SKIM BY THE
REGION.
MFR WATCHES/WARNINGS/ADVISORIES
OR...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR ORZ624-625.
RED FLAG WARNING FROM 2 PM TO 8 PM PDT MONDAY FOR ORZ624-625.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 2 AM PDT MONDAY
FOR PZZ350-356-370.
HAZARDOUS SEAS WARNING UNTIL 2 AM PDT MONDAY FOR PZZ356-376.
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