800
FXUS66 KMFR 311116
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
416 AM PDT THU JUL 31 2025
DISCUSSION
SHOWERS HAVE MOVED NORTH OUT OF OUR FORECAST AREA AFTER YET
ANOTHER DAY OF THUNDERSTORMS ACROSS THE REGION. LIGHTNING WAS ON
THE HIGHER SIDE TODAY WITH THE NLDN DETECTING ~875 CLOUD TO GROUND
FLASHES WITH THE ENTLN DETECTING AROUND 2900 CLOUD TO GROUND
FLASHES. STORMS WERE WET AT TIMES, PERHAPS THE MAJORITY OF THE
TIME, EVEN WITH CLOUD BASES AROUND 10K FEET AND PWATS AROUND 0.6
INCHES ACCORDING TO GFS FORECAST SOUNDINGS. REGARDLESS, SOME RAWS
SITES REPORTED 0.5 TO 0.75 INCHES OF RAIN EAST OF THE CASCADES
WEDNESDAY EVENING, PERHAPS DUE TO MULTIPLE STORMS MOVING OVER THE
SURFACE STATIONS. IN ANY CASE, THAT WAS A LITTLE MORE RAIN THAN WE
WERE EXPECTING.
FINALLY ONTO THE FORECAST, WE SHOULD SEE MORE LIGHTNING ON
THURSDAY, ALTHOUGH THE ATMOSPHERIC PARAMETERS HINT TO WET STORMS
WITH PWATS INCREASING AND NOT AS LARGE INVERTED VS. THE SPC SREF
PROBABILITY FOR OVER 100 CLOUD TO GROUND FLASHES WITHIN 20KM OF
ANY POINT IS AT 6 PERCENT IN NORTHERN CALIFORNIA WITH THE
PROBABILITIES DROPPING OFF THE FARTHER TO THE NORTH AND EAST.
WE'LL KEEP THE RED FLAG WARNINGS GOING FOR NOW GIVEN THAT THE
LIGHTNING WILL BE CONSIDERED ABUNDANT, ALTHOUGH IT'S HARD TO SEE
NEW FIRES STARTING IN THIS ENVIRONMENT IF THEY HAVEN'T REALLY
PICKED UP RECENTLY.
BY FRIDAY, A SHORTWAVE EMERGES FROM CENTRAL CALIFORNIA AND WE
SHOULD SEE MORE THUNDERSTORMS DEVELOP ACROSS THE AREA DURING
FRIDAY AND SATURDAY. FORECAST SOUNDINGS HINT THAT STORMS COULD
LEAN DRIER FRIDAY AFTERNOON. SOUNDINGS SHOW LARGER INVERTED VS
WITH STORM BASES AROUND 10K FEET. IT'S WORTH NOTING THE
PROBABILITY OF CLOUD TO GROUND LIGHTNING TRENDS LOWER FRIDAY AND
SATURDAY. THAT IS INDEED LOWER COMPARED TO THE 80 TO 90 PERCENT
CHANCES WE'VE SEEN OVER THE PREVIOUS FEW DAYS.
SUNDAY IS PRETTY INTERESTING AS A DEEPER WAVE MOVES INTO THE
OREGON COAST. WE WILL LIKELY SEE THUNDERSTORMS MIXED WITH RAIN
SHOWERS BY THE AFTERNOON HOURS. ONE THING THAT IS A BIG CHANGE
WITH THE SUNDAY EVENT IS THAT STORM MOTION SHOULD BE A LITTLE
FASTER WITH 0-6KM SHEAR AROUND 30-40KTS ON THE GFS. A COLD FRONT,
OR AT LEAST SOME COOLER AIR WILL ACCOMPANY THIS WAVE WITH HIGH
TEMPERATURES TRENDING ABOUT 6 DEGREES COOLER COMPARED TO SATURDAY.
THOSE HIGHS WOULD IN FACT PUSH US BELOW NORMAL FOR THIS TIME OF
YEAR.
FINALLY BY NEXT WEEK WE'RE LOOKING AT SOME DRIER WEATHER AND
FINALLY BREAKING THIS THUNDERSTORM STREAK WE'RE CURRENTLY ON.
TEMPERATURES WILL WARM BACK UP TO SUMMER TIME NORMALS THROUGH THE
REMAINDER OF THE WEEK.
-SMITH
AVIATION...31/06Z TAFS
ALONG THE COAST, LIFR/IFR CONDITIONS
PERSIST NORTH OF CAPE BLANCO WITH MAINLY VFR SOUTH OF THE CAPE.
CONDITIONS WILL LIKELY PERSIST INTO THURSDAY MORNING WITH AREAS OF
MVFR/IFR CEILINGS CONTINUING NORTH OF CAPE BLANCO THURSDAY
AFTERNOON, FOLLOWED BY A RETURN OF LIFR/IFR THURSDAY EVENING. LOCAL
IFR CONDITIONS MAY DEVELOP SOUTH OF CAPE BLANCO NEAR BROOKINGS LATE
TONIGHT AND EARLY THURSDAY MORNING.
INLAND, EXPECT MAINLY VFR CONDITIONS. ISOLATED THUNDERSTORMS AND
SHOWERS WILL CONTINUE OVERNIGHT AND THURSDAY MORNING, MAINLY EAST OF
THE SOUTHERN OREGON CASCADES. THEN, THURSDAY AFTERNOON AND EVENING,
EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP ACROSS
NORTHERN CALIFORNIA AND FROM THE SOUTHERN OREGON CASCADES EAST,
INCLUDING AT KLAMATH FALLS, KLMT. THERE IS A LOW CHANCE (10-15%) FOR
THUNDERSTORMS TO DEVELOP IN THE MEDFORD AREA, INCLUDING KMFR, DURING
THE LATE AFTERNOON AND EVENING. GUSTY WINDS, HAIL, LOCAL HEAVY
DOWNPOURS AND LIGHTNING ARE THE MAIN CONCERNS WITH THESE STORMS.
MARINE...UPDATED 330 AM PDT THURSDAY, JULY 31, 2025
A THERMAL
TROUGH ALONG THE COAST WILL PERSIST THROUGH FRIDAY EVENING
BRINGING STEEP SEAS AND GUSTY WINDS TO AREAS FROM PORT ORFORD
SOUTH. WINDS AND SEAS WILL PEAK IN THE LATE AFTERNOON AND
EVENINGS. WINDS MAY TREND LIGHTER SATURDAY AND SUNDAY. HOWEVER,
CONFIDENCE IS LOW AND MAY SEE AREAS OF STEEP SEAS AND GUSTY WINDS
PERSIST INTO THE WEEKEND ACROSS THE SOUTHERN WATERS.. THEN, EARLY
NEXT WEEK GUSTY WINDS AND STEEP SEAS ARE LIKELY AGAIN FOR THE
WATERS SOUTH OF CAPE BLANCO.
MFR WATCHES/WARNINGS/ADVISORIES
OR...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS
EVENING FOR ORZ623>625.
CA...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS
EVENING FOR CAZ280-281-284-285.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 11 PM PDT FRIDAY
FOR PZZ356-376.
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