Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 010354
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
854 PM PDT TUE JUN 30 2015

.DISCUSSION...A LONE THUNDERSTORM DEVELOPED OVER EASTERN LASSEN
COUNTY THIS AFTERNOON COINCIDENT WITH BEST MID-LEVEL MOISTURE ON
THE NORTHWESTERN PERIPHERY OF THE UPPER HIGH CENTERED OVER
SOUTHERN UTAH. BUT THIS CELL MOVED JUST SOUTHEAST OF MODOC COUNTY
THIS EVENING AND WILL DISSIPATE WITH THE SETTING SUN. WE`RE NOT
EXPECTING ANY THUNDERSTORMS OVER THE CWA OVERNIGHT.

WE`LL SEE THE UPPER HIGH BUILD WEST-NORTHWEST TOWARD THE AREA
OVER THE NEXT 24-48 HOURS AND THIS WILL BRING MORE HOT WEATHER FOR
MID-LATE WEEK. WE REACHED 103 DEGREES AT THE MEDFORD ROGUE VALLEY
INTERNATIONAL AIRPORT THIS AFTERNOON AND WE`LL BE A FEW TO SEVERAL
DEGREES HIGHER ON WEDNESDAY AND THURSDAY. THUNDERSTORM CHANCES
WILL ALSO GRADUALLY INCREASE DURING THIS TIME FRAME WITH THE FOCUS
ACROSS NORTHERN CALIFORNIA. PLEASE SEE THE PREVIOUS DISCUSSION
BELOW FOR THE SPECIFICS.

THE MARINE LAYER ALONG THE IMMEDIATE PACNW COAST WILL HAVE A
TENDENCY TO SHRINK SOUTHWARD AND MAY GO AWAY COMPLETELY ALONG OUR
NORTH COAST OVERNIGHT AS OFFSHORE FLOW OVER THE COAST RANGES SETS
IN. SPILDE

&&

.AVIATION...FOR THE 01/00Z TAF CYCLE...AREAS OF MVFR/IFR CIGS ARE
MAKING THEIR RETURN TO AREAS ALONG THE COAST NORTH OF CAPE BLANCO
AND A SMALL AREA ALONG THE FAR SOUTHERN OREGON COAST. LOWERED
CONDITIONS ARE LIKELY TO REMAIN IN PLACE OVERNIGHT AND INTO THE
EARLY MORNING HOURS BEFORE BURNING OFF BY NOON. EXPECT GUSTY NORTH
WINDS DURING THE AFTERNOON AND EVENING. OVER INLAND AREAS...VFR
CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. -BPN

&&

.MARINE...UPDATED 830 PM PDT TUESDAY 30 JUNE 2015...A STRONG
THERMAL TROUGH NEAR THE COAST WILL WEAKEN SLIGHTLY WEDNESDAY INTO
THURSDAY, BUT WILL PERSIST INTO THE WEEKEND. EXPECT HAZARDOUS
SEAS AND GALES SOUTH OF GOLD BEACH THROUGH WEDNESDAY, WITH
ADVISORY LEVEL WINDS ELSEWHERE. GALES MAY RETURN LATER IN THE
WEEK. NO CHANGES IN THE PATTERN ARE EXPECTED UNTIL SUNDAY. SPILDE

&&

.PREV DISCUSSION... /ISSUED 313 PM PDT TUE JUN 30 2015/

DISCUSSION...
HOT TEMPERATURES WILL BECOME HOTTER WEDNESDAY AND THURSDAY...AND
THEN ARE EXPECTED TO TREND SLOWLY DOWNWARD THIS WEEKEND INTO EARLY
NEXT WEEK. RECORDS ARE EXPECTED TO BE BROKEN THROUGH THE 4TH OF
JULY. THESE ARE HIGHLIGHTED IN A WEATHER STORY ON OUR WEBSITE.
INTERESTINGLY, FOR MANY AREAS WEST OF THE CASCADES, RECORDS
PROBABLY WILL NOT BE BROKEN WHEN TEMPERATURES ARE AT THEIR PEAK
THROUGH FRIDAY BECAUSE THE RECORDS ARE QUITE HIGH FOR THOSE DAYS.
MORE RECORDS ARE LIKELY TO BE BROKEN ON THE WEST SIDE THIS
WEEKEND WHEN THEY ARE NOT QUITE AS HIGH. PLEASE SEE THE HEAT
ADVISORY AND SPECIAL WEATHER STATEMENT PRODUCTS FOR MORE
DETAILED INFORMATION.

ON THE TAIL END OF THE HEAT WAVES IN OUR FORECAST AREA WE ALSO
OFTEN EXPECT THUNDERSTORMS. POSSIBILITIES FOR THUNDERSTORMS LOOK
TO GENERALLY INCREASE THROUGH SUNDAY. THERE ARE A COUPLE OF UPPER
LEVEL IMPULSES TO KEEP AN EYE ON THIS WEEK INTO THIS WEEKEND,
CENTERED ON LATE THURSDAY INTO FRIDAY, AND LATE SATURDAY INTO
SUNDAY. THE FIRST OF THESE IMPULSES IS EXPECTED TO GENERATE
ISOLATED THUNDERSTORMS ACROSS MAINLY NORTHERN CALIFORNIA, BUT
THERE IS A POSSIBILITY STORMS COULD BE BRIEFLY SCATTERED IN
SISKIYOU COUNTY. THE NAM12 INDICATES THE SHORTWAVE TROUGH
RESPONSIBLE FOR TRIGGERING THESE THUNDERSTORMS TO BE FURTHER
NORTH AND MORE ROBUST THAN DOES THE GFS40. THE SECOND OF THESE
IMPULSE SATURDAY NIGHT INTO SUNDAY APPEARS MORE ROBUST AND IS
PRESENT IN BOTH THE GFS AND ECMWF MODELS. THIS FEATURE COULD PUSH
THE THREAT OF THUNDERSTORMS WEST OF THE CASCADES, BUT GIVEN IT`S
PRETTY FAR OUT IN TIME, THERE`S PLENTY OF ROOM FOR THIS TO CHANGE.

OF NOTE, BY THE MIDDLE OF NEXT WEEK THE GFS INDICATES
TEMPERATURES FALLING OFF APPRECIABLY ACROSS THE AREA, WHILE THE
ECMWF HEATS THEM UP BACK INTO RECORD TERRITORY. AT THIS POINT IT`S
TOO EARLY TO TELL WHAT WILL OCCUR, BUT MOST ENSEMBLE GUIDANCE
CONTINUES TO INDICATE WARMER THAN NORMAL CONDITIONS CONTINUING
THROUGH THE MIDDLE OF THE MONTH. BTL

AVIATION...FOR THE 30/18Z TAF CYCLE...
ALONG THE COAST...AREAS OF MVFR/IFR CIGS HAVE BEEN STUBBORN TO
BURN OFF AND SOME GUIDANCE IS SUGGESTING IT WILL NEVER CLEAR. BUT
WITH WINDS GUSTS OF 30KT EXPECTED AT KOTH, HAVE A HARD TIME
BELIEVING IT WON`T CLEAR EVEN IF JUST TEMPORARY. IF/WHEN CIGS
CLEAR, IT LIKELY WON`T BE UNTIL LATER THIS AFTERNOON AND WILL
LIKELY RETURN TO THE SAME AREAS OVERNIGHT BETWEEN 03-06Z. OVER
INLAND AREAS...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD.
-MND

MARINE...UPDATED 230 PM PDT TUESDAY 30 JUNE 2015...
A THERMAL TROUGH WILL CONTINUE TO STRENGTHEN THROUGH THIS
AFTERNOON AND EVENING. THE TROUGH WILL THEN WEAKEN SLIGHTLY
WEDNESDAY INTO THURSDAY, BUT IT WILL PERSIST INTO THE WEEKEND.
EXPECT GALES SOUTH OF GOLD BEACH THROUGH WEDNESDAY, WITH ADVISORY
LEVEL WINDS ELSEWHERE. GALES MAY RETURN LATER IN THE WEEK. WITH
STRONG NORTH WINDS, SEAS WILL BECOME HAZARDOUS AND REMAIN SO INTO
THE WEEKEND. NO CHANGES IN THE PATTERN ARE EXPECTED UNTIL SUNDAY.
-BPN

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HEAT ADVISORY FROM 1 PM WEDNESDAY TO 11 PM PDT FRIDAY FOR
     ORZ023.
     HEAT ADVISORY FROM 1 PM WEDNESDAY TO 11 PM PDT FRIDAY FOR
     ORZ024-026.

CA...HEAT ADVISORY FROM 1 PM WEDNESDAY TO 11 PM PDT FRIDAY FOR
     CAZ080-081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM
     PDT FRIDAY FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT FRIDAY
     FOR PZZ350-356-370-376.
     HAZARDOUS SEAS WARNING UNTIL 5 AM PDT THURSDAY FOR PZZ356.
     GALE WARNING UNTIL 11 PM PDT WEDNESDAY FOR PZZ376.
     HAZARDOUS SEAS WARNING UNTIL 11 PM PDT FRIDAY FOR PZZ376.

$$

MAS/BTL/BPN



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