Area Forecast Discussion
Issued by NWS Medford, OR

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000
FXUS66 KMFR 300929
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
229 AM PDT WED JUL 30 2014

.DISCUSSION...THE NEXT COUPLE OF DAYS WILL BE POTENTIALLY HIGH
IMPACT DAYS FOR FIRE WEATHER AND SEVERE WEATHER, AND THUS ALL OF THE
FOCUS THIS MORNING HAS BEEN ON THE FORECAST FOR THE NEXT 48 HOURS.

ON TUESDAY, THUNDERSTORMS FORMED IN ROUGHLY THE EXPECTED LOCATIONS
AND APPROXIMATELY RIGHT ON TIME. STORMS BECAME MOST INTENSE AND THE
MOST LIGHTNING WAS OBSERVED IN THE EARLY EVENING FROM NEAR MT.
ASHLAND UP THROUGH THE CASCADES. STORMS ACTUALLY APPROACHED SEVERE
LEVELS AT TIMES WITH AT LEAST ONE MID LEVEL MESOCYCLONE OBSERVED ON
RADAR (ALONG HIGHWAY 97 NEAR CHEMULT) AND A COUPLE OF OVERSHOOTING
TOPS SEEN IN SATELLITE DATA. MOST OF OUR AREA WAS VERY UNSTABLE, BUT
THE WEST SIDE WAS LARGELY CAPPED AT AROUND 700 MB. THE PREVIOUS
SHIFT MADE THE ASTUTE OBSERVATION THAT STORMS FORMED WITHIN THE AREA
OF CONCENTRATED MID LEVEL MOISTURE, THAT IS WHERE 700-500MB
HUMIDITIES EXCEEDED 60%. THE WEST SIDE WAS CAPPED BELOW MUCH OF THIS
MOISTURE, AND NOT SURPRISINGLY, STORMS MADE LITTLE PROGRESS OFF THE
MOUNTAINS AS A RESULT.

THAT IS NOT EXPECTED TO BE THE CASE TODAY. WE SHOULD HAVE EVERY BIT
AS MUCH INSTABILITY TODAY, BUT THE MODELS SHOW A WESTWARD SURGE IN
MID LEVEL MOISTURE WITH THE EDGE OF THE DEEP MOISTURE MOVING AS FAR
WEST AS GRANTS PASS. IN ADDITION, BOTH THE GFS AND NAM SHOW A DECENT
SHORTWAVE MOVING THROUGH THIS AFTERNOON, AND STEERING FLOW BACKS A
BIT MORE TOWARD THE SOUTH. THERE IS A SHORT WAVE JUST OFF THE COAST
NOW, WHICH SHOULDN`T DO MUCH AT THIS TIME OF DAY, BUT MORE ENERGY IS
NOTED MOVING NORTH THROUGH CENTRAL CALIFORNIA. IN FACT, THERE WERE
JUST A FEW LIGHTNING STRIKES INLAND FROM THE BAY AREA ASSOCIATED
WITH SOME OF THAT ENERGY, WHICH SEEMS TO BE WHAT THE MODELS ARE
PICKING UP ON. ALL OF THIS MEANS THAT WE SHOULD SEE AT LEAST AS MUCH
ACTIVITY TODAY AS YESTERDAY, AND WE PROBABLY WILL SEE STORMS EVEN ON
THE WEST SIDE. POPS WERE ADJUSTED TO THIS THINKING AND THE RED FLAG
WARNING WILL BE NUDGED WEST TO INCLUDE THE ROGUE VALLEY TODAY.

AS TO WHETHER THUNDERSTORMS WILL BE SEVERE TODAY...THERE IS LITTLE
REASON TO BELIEVE WE CAN`T GET A SEVERE STORM OR TWO GIVEN WHAT WE
SAW ON TUESDAY. DON`T EXPECT WIDESPREAD SEVERE STORMS, BUT IN
ADDITION TO HEAVY RAIN, ISOLATED LARGE HAIL AND DAMAGING WIND
GUSTS CAN`T BE RULED OUT. THE MOST LIKELY LOCATION FOR THAT WILL
BE KLAMATH COUNTY AGAIN.

IT REMAINS PLENTY UNSTABLE ON THURSDAY AS WELL. WHILE THERE WILL BE
A LITTLE LESS MOISTURE, THERE IS STILL A DECENT TRIGGER IN THE FORM
OF A 500 MB SHORTWAVE. THUS, COVERAGE AND LOCATION OF STORMS ON
THURSDAY LOOKS ROUGHLY THE SAME AS WEDNESDAY, AND POPS WERE ADJUSTED
UP AND FURTHER WEST THURSDAY AS WELL. WE WILL ALSO BE EXPANDING THE
FIRE WEATHER WATCH FOR THURSDAY TO INCLUDE SIMILAR AREAS TO WHAT THE
RED FLAG WARNING COVERS TODAY.

THINGS REMAIN UNSTABLE ON FRIDAY, BUT THERE IS A NOTICEABLE SHIFT
INLAND WITH ACTIVITY, AND THUS THUNDERSTORMS OUGHT TO BE CONFINED TO
EAST SIDE AREAS ON FRIDAY. NO CHANGES WERE MADE TO THE FORECAST
BEYOND FRIDAY. -WRIGHT

&&

.AVIATION...BASED ON THE 30/06Z TAFS...

ALONG THE COAST...WITH THE EXCEPTION OF A SMALL AREA OF VFR NEAR
PORT ORFORD/GOLD BEACH...EXPECT LIFR THROUGH WEDNESDAY MORNING. SOME
AREAS WILL CLEAR TO VFR IN THE AFTERNOON, BUT LOWER CONDITIONS WILL
RETURN BY WEDNESDAY EVENING. HIGHER TERRAIN JUST INLAND WILL ALSO BE
OBSCURED. ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY
EVENING. AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP FROM THE
SISKIYOUS AND CASCADES EASTWARD. SOUTH FLOW MAY BRING ISOLATED
THUNDERSTORMS INTO SOME OF THE WEST SIDE VALLEYS TOO, SO
HAVE INCLUDED VCTS IN THE KMFR TAF. STRONGER STORMS WILL HAVE GUSTY
OUTFLOW WINDS, HAIL AND HEAVY RAINFALL. SPILDE

&&

.MARINE...UPDATED 300 AM PDT 30 JULY 2014...

THE CURRENT PATTERN...WITH SOME SLIGHT DAY-TO-DAY VARIATION...WILL
PERSIST THROUGH THE WEEKEND. OFFSHORE HIGH PRESSURE AND A THERMAL
TROUGH OVER NORTHERN CALIFORNIA WILL COMBINE TO MAINTAIN STEEP WIND
WAVE DOMINATED SEAS AND AREAS OF SMALL CRAFT ADVISORY WINDS INTO THE
WEEKEND...WITH THE STRONGEST WINDS AND STEEPEST SEAS FROM CAPE
BLANCO SOUTH IN THE AFTERNOONS AND EVENINGS.  WINDS MAY INCREASE TO
GALES WITH VERY STEEP SEAS BY FRIDAY AFTERNOON FOR AREAS SOUTH OF
CAPE BLANCO. CONFIDENCE IS MODERATE ON THE GALE AND VERY STEEP SEAS
POTENTIAL...AS MODELS HAVE BEEN GENERALLY CONSISTENT IN SHOWING
HIGH-END SMALL CRAFT CONDITIONS FRIDAY AFTERNOON...WITH A FEW RUNS
POINTING TOWARDS LOW-END GALE CONDITIONS. SK

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS
     EVENING FOR ORZ617-620>625.
     FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
     EVENING FOR ORZ617-620>625.

CA...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS
     EVENING FOR CAZ280>282-284-285.
     FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
     EVENING FOR CAZ280>282-284-285.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 PM
     PDT FRIDAY FOR PZZ356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT FRIDAY
     FOR PZZ350-356-370-376.
     SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM THURSDAY TO 11 PM PDT
     FRIDAY FOR PZZ350-370.
     GALE WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY EVENING FOR
     PZZ376.
     HAZARDOUS SEAS WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY
     EVENING FOR PZZ376.

$$





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