641  
FXUS66 KMFR 141736  
AFDMFR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MEDFORD OR  
1036 AM PDT MON JUL 14 2025  
   
DISCUSSION
 
UPDATED AVIATION SECTION  
 

 
   
AVIATION...14/18Z TAFS
 
THE MARINE LAYER IS STARTING TO  
BURN OFF THIS MORNING. INLAND TAF SITES WILL LIKELY SEE PLENTY OF  
SUNSHINE TODAY WITH VFR CONDITIONS DOMINATING MUCH OF THE REGION,  
BUT A SMALL CHANCE OF THUNDERSTORMS TODAY COULD IMPACT NORTHERN  
CALIFORNIA AND SOUTH CENTRAL OREGON. BLOW OFF CLOUDS FROM THESE  
THUNDERSTORMS COULD IMPACT KLMT, BUT IT SHOULD BE NOTED THERE IS A  
10% CHANCE KLAMATH TERMINAL COULD SEE AN ISOLATED THUNDERSTORM.  
 

 
 
PREV DISCUSSION... /ISSUED 340 AM PDT MON JUL 14 2025/  
 
DISCUSSION (TODAY THROUGH SUNDAY)...  
 
OVERVIEW:  
 
A VERY SIMILAR DAY TO YESTERDAY IS SHAPING UP FOR TODAY AS WE ARE  
ONCE AGAIN LOOKING AT A SMALL CHANCE (~20%) FOR THUNDERSTORMS IN  
ADDITION TO HEAT RELATED HAZARDS ACROSS THE AREA. THE HEAT WILL  
ALSO PLAY A ROLE ON ELEVATED FIRE WEATHER CONDITIONS THIS  
AFTERNOON/EARLY EVENING, BUT WE WILL FALL SHORT OF CRITICAL WINDS  
AND RH THAT WOULD WARRANT A RED FLAG WARNING. BEYOND TODAY, HEAT  
RELATED HAZARDS WILL BE THE MAIN IMPACT AS TRIPLE DIGITS ARE  
POSSIBLE FOR LOW ELEVATION AREAS WEST OF THE CASCADES THROUGH MID-  
WEEK.  
 
FURTHER DETAILS:  
 
AT 500MB, WE HAVE A BROAD AREA OF HIGH PRESSURE OVER WESTERN PARTS  
OF THE CONUS WHICH IS PART OF A LARGER AREA OF HIGH PRESSURE THAT  
INCLUDES AN AREA FARTHER WEST OVER THE PACIFIC. AT THE SAME TIME, WE  
HAVE A SHORTWAVE TROUGH PASSING OVER SOUTHERN PARTS OF BRITISH  
COLUMBIA. WE WILL SEE WEAK PVA ACROSS THE AREA TODAY UNDER THIS  
SETUP, AND AS WE REACH PEAK HEATING TODAY WE WILL LIKELY SEE  
CONVECTIVE TEMPERATURES REACHED. IN A SIMILAR FASHION AS YESTERDAY,  
DURING PEAK HEATING THERE MAY BE JUST ENOUGH UPPER LEVEL DYNAMICS TO  
SUPPORT A COUPLE ISOLATED THUNDERSTORMS THROUGH EARLY PARTS OF THE  
EVENING. THESE CHANCES ARE FOR MAINLY NORTHERN CALIFORNIA, AND  
SOUTHERN PARTS OF BOTH KLAMATH AND LAKE COUNTIES WITH THESE CHANCES  
AROUND 15-20 PERCENT. NOT EXPECTING MUCH--IF ANY--ACTIVITY AFTER  
SUNSET. MAIN THREAT WITH THESE THUNDERSTORMS IF THEY FORM WOULD BE  
LIGHTNING AND GUSTY ERRATIC WIND SPEEDS.  
 
WITH HIGH PRESSURE DOMINATING THE REGION, EXPECTING THE NWS HEATRISK  
TODAY TO BE MODERATE TO PERHAPS ISOLATED MAJOR, AND OUR HEAT RELATED  
HAZARDS WILL CONTINUE THROUGH THIS AFTERNOON AND EARLY EVENING.  
THESE HAZARDS WILL REMAIN IN PLACE FOR TOMORROW AND LIKELY EXTENDED  
INTO WEDNESDAY AS WELL. SLIGHTLY "COOLER" TEMPERATURES EXPECTED ON  
THURSDAY, BUT UPPER 90S STILL POSSIBLE FOR WESTSIDE AREAS.  
TEMPERATURES MAY FINALLY GET BACK DOWN NEAR NORMAL BY SUNDAY.  
 
LASTLY, WHILE ITS NOT CURRENTLY MENTIONED IN THE FORECAST, THERE  
WILL BE VERY WEAK UPPER LEVEL ENERGY ACROSS THE AREA TUESDAY, AND  
AS WE ENTER PEAK HEATING THERE COULD BE TOWERING CUMULUS THAT  
MATURE INTO A THUNDERSTORM. THAT SAID, AFTER TODAY CHANCES FOR ANY  
PRECIPITATION OR THUNDERSTORMS IS LESS THAN 10 PERCENT IN THE  
OFFICIAL FORECAST.  
 
-GUERRERO  
 
AVIATION (06Z TAFS)...  
 
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD FOR MOST  
LOCATIONS. THE MARINE LAYER REMAINS JUST OFFSHORE NORTH OF CAPE  
BLANCO AS WELL AS FROM GOLD BEACH SOUTHWARD. ISOLATED SHOWERS  
CONTINUE EAST OF THE CASCADES, BUT LIGHTNING ACTIVITY HAS COME TO  
AN END. MARINE STRATUS IS EXPECTED TO RETURN TO COASTAL LOCATIONS  
MUCH LIKE PREVIOUS NIGHTS. HOWEVER, GUIDANCE SHOWS THE POTENTIAL  
FOR GUSTY WINDS TO PERSIST OVERNIGHT ALONG THE COAST AND THIS MAY  
KEEP VISIBILITIES FROM REACHING LIFR CONDITIONS. REGARDLESS, LIFR  
CEILINGS ARE EXPECTED.  
 
STRONG NORTH WINDS RETURN TO THE COAST AND UMPQUA BASIN FAIRLY EARLY  
ON MONDAY (BETWEEN 16Z-18Z), AND GUSTS UP TO 35 KTS ARE POSSIBLE AT  
NORTH BEND. ADDITIONALLY, ANOTHER ROUND OF ISOLATED SHOWERS  
THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHERN CALIFORNIA AND  
SOUTHERN LAKE/KLAMATH COUNTIES MONDAY AFTERNOON.  
 
/BR-Y  
 
MARINE...  
 
OUR THERMAL TROUGH PATTERN WILL CONTINUE THROUGH AT LEAST THE  
MIDDLE OF THIS WEEK. THIS WILL MAINTAIN STRONG NORTH WINDS AND  
STEEP TO VERY STEEP WIND-DRIVEN SEAS ACROSS ALL WATERS. GALES ARE  
EXPECTED IN THE AFTERNOONS/EVENINGS MAINLY SOUTH OF PORT ORFORD  
AND BEYOND 5 NM FROM SHORE. CONDITIONS COULD BEGIN TO IMPROVE  
AROUND MID-WEEK AS WE TRANSITION AWAY FROM WIND-DRIVEN SEAS  
 
FIRE WEATHER...  
 
ELEVATED FIRE WEATHER CONCERNS EXPECTED AGAIN TODAY AS WE FALL SHORT  
OF ANY OVERLAP OF CRITICAL WINDS AND RH. A THERMAL TROUGH CONTINUES  
OVER LOCATIONS WEST OF THE CASCADES THROUGH TOMORROW WITH EASTERLY  
BREEZES OVER THE CASCADES TOMORROW EVENING AND WEDNESDAY MORNING. A  
COLD FRONT IS FORECAST TO PASS THROUGH THE REGION TODAY/TONIGHT  
BEHIND AN UPPER LEVEL WAVE DIVING SOUTH/SOUTHEAST FROM BRITISH  
COLUMBIA. THERE MAY BE JUST ENOUGH UPPER LEVEL ENERGY THIS AFTERNOON  
WHEN COUPLED WITH PEAK HEATING COULD PRODUCE AN ISOLATED  
THUNDERSTORM OR TWO THIS AFTERNOON/EARLY EVENING. THIS CHANCES ARE  
LOW (~20%) AND PRIMARILY FOR NORTHERN CALIFORNIA AND BOTH KLAMATH  
AND LAKE COUNTIES. WE WILL NEED TO MONITOR TUESDAY AS WE COULD SEE  
ANOTHER ROUND OF LOW END THUNDERSTORM CHANCES, BUT THESE CHANCES ARE  
VERY LOW (~5-10%) AT THIS TIME.  
 
THIS HOT AND DRY WEATHER PATTERN WILL PERSIST THROUGH THIS WEEK, BUT  
TEMPERATURES DO TREND A BIT LOWER BY THE WEEKEND WITH TEMPERATURES  
NEAR NORMAL BY SUNDAY.  
 

 
   
MFR WATCHES/WARNINGS/ADVISORIES
 
 
OR...EXTREME HEAT WARNING UNTIL 8 PM PDT TUESDAY FOR ORZ024-026.  
 
HEAT ADVISORY UNTIL 8 PM PDT TUESDAY FOR ORZ023-025-029>031.  
 
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT TUESDAY FOR CAZ080-081.  
 
HEAT ADVISORY UNTIL 8 PM PDT TUESDAY FOR CAZ082>085.  
 
PACIFIC COASTAL WATERS...GALE WARNING UNTIL 11 PM PDT TUESDAY FOR  
PZZ356-376.  
 
SMALL CRAFT ADVISORY UNTIL 11 PM PDT TUESDAY FOR PZZ350-370.  
 

 
 

 
 
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