Hail in Oregon, July 8, 2015

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MEDFORD OR
410 PM PDT WED JUL 8 2015

UPDATED FIRE WEATHER SECTION

.DISCUSSION...ISOLATED THUNDERSTORMS ARE ALREADY STARTING TO FIRE UP
AWAY FROM THE CLOUD SHIELD IN SISKIYOU AND DOUGLAS COUNTY. ALSO A
AREA OF THUNDERSTORMS HAS DEVELOPED JUST EAST OF MODOC COUNTY AND
SLOWLY MOVING WESTWARD. THE LATEST WATER VAPOR IMAGE SHOWS THE
PESKY UPPER LOW JUST WEST OF THE SAN FRANCISCO BAY AREA AND A
WEAK UPPER TROUGH THAT IS MOVING THROUGH EASTERN WASHINGTON WITH A
DEFORMATION ZONE IS SETTING UP OVER OUR AREA. THE POSITION OF THE
UPPER LOW AND DEFORMATION ZONE LOCATIONS IS CONCERNING IN THAT
IT'S PRIMING THE ATMOSPHERE FOR SCATTERED SHOWERS AND
THUNDERSTORMS AS THE AFTERNOON PROGRESSES INTO THIS EVENING. A
LOOK AT THE MESOSCALE ANALYSIS SHOWS CAPE VALUES NEAR 1000
J/KG...BUT UNLIKE YESTERDAY...THERE IS ALSO CIN MAINLY WHERE THE
CLOUD SHIELD IS. THIS MAY PUT A CAP ON THE AMOUNT OF STORMS WE
GET, BUT WOULD NOT PUT TOO MUCH FAITH IN THAT.

THE MODELS SHOW PLENTY OF SHORTWAVES MOVING INTO THE AREA AROUND THE
TIME OF MAX HEATING, THUS PROVIDING THE TRIGGER FOR STORMS TO
DEVELOP. ALSO PWATS ARE OVER AN INCH FOR MANY LOCATIONS WITH THE
HIGHEST AMOUNTS WEST OF THE CASCADES AND NORTHERN CAL. IN FACT THE
MORNING SOUNDING SHOWS PWATS OF 1.35 INCHES AND THE NAEFS MEAN PWATS
PERCENTILE IS IS IN THE 99TH PERCENTILE. IN A NUTSHELL THERE IS
PLENTY OF JUICE OUT THERE.

WE EXPECT THUNDERSTORMS TO BECOME SCATTERED TO NUMEROUS. WE THINK
THE BEST CHANCE FOR NUMEROUS THUNDERSTORMS WILL BE ALONG THE
CASCADES...SISKIYOUS AND PARTS OF THE EAST SIDE LATE THIS AFTERNOON
INTO THIS EVENING. THAT'S NOT TO SAY THE SAME AREAS WILL GET
HIT...SAY FOR EXAMPLE THE STORM THAT DEVELOPED IN THE ROGUE VALLEY
YESTERDAY EVENING. WHAT IT DOES MEAN IS THAT CONDITIONS COULD BE
FAVORABLE FOR SCATTERED TO NUMEROUS STORMS...SOME OF WHICH COULD
PRODUCE MODERATE TO HEAVY DOWNPOURS AND SMALL HAIL AND GUSTY WINDS.
OF NOTE THE MODELS ARE SHOWING FASTER STEERING WINDS BETWEEN 15-25
KTS THIS AFTERNOON AND EVENING...THEREFORE STORMS THAT DEVELOP WILL
TEND TO MOVE FASTER THAN THEY DID YESTERDAY AND MOVE WEST TO
SOUTHWEST. HOWEVER THERE IS STILL CONCERN FOR FLASH
FLOODING...ESPECIALLY FOR THE BURN SCARS IN SISKIYOU COUNTY AND
URBAN FLOODING...SO WE'LL KEEP THE FLASH FLOOD WATCH OUT. PLEASE
SEE FAAMFR FOR MORE DETAILS.

ADDITIONAL SHORTWAVES WILL MOVE THROUGH TONIGHT, SO THERE'S A CHANCE
FOR THUNDERSTORMS TO PERSIST INTO THE OVERNIGHT HOURS. ESPECIALLY IN
NORTHERN CAL. ELSEWHERE...WE'LL HAVE MOSTLY RAIN SHOWERS, BUT COULD
NOT RULE OUT ISOLATED THUNDER.

THE ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM PATTERN WILL
PERSIST OVER A GOOD CHUNK OF THE AREA THURSDAY AS THE UPPER LOW
NEARLY STALLS IN CALIFORNIA AND WEAKENS. DYNAMICS AND INSTABILITY
REMAIN FAVORABLE OVER THE AREA. CONFIDENCE IS LOW TO MODERATE AS TO
WHERE THE BEST CHANCE FOR STORMS WILL BE. CURRENT THINKING IS STORMS
WILL BE MOST FREQUENT ALONG AND EAST OF THE CASCADES AND ALONG THE
SISKIYOUS AND NORTHERN CAL...BUT KEEP IN MIND THE DETAILS ON THIS
COULD CHANGE.

THE UPPER LOW WILL CONTINUE WEAKEN AND OPEN TO A WEAK UPPER TROUGH
ON FRIDAY WITH THE BEST CHANCE FOR THUNDERSTORMS ALONG AND EAST OF
THE CASCADES. BEFORE WEST WINDS ALOFT BEGIN TO STABILIZE AND DRY
THINGS OUT WEST OF THE CASCADES ON SATURDAY, BUT IT MAY REMAIN
UNSTABLE ENOUGH FOR THUNDERSTORMS TO BE A CONCERN EAST OF THE
CASCADES. ONE GOOD THING IS TEMPERATURES WILL BE COOLER AND COULD
GET TO NEAR OR SLIGHTLY BELOW NORMAL THIS WEEKEND. -PETRUCELLI

&&

.FIRE WEATHER...UPDATED 400 PM PDT, WEDNESDAY 8 JULY 2015... LOW
PRESSURE CENTERED NEAR MONTERREY BAY, CALIFORNIA WILL CONTINUE TO
PIVOT LOW PRESSURE IMPULSES INTO THE AREA THROUGH THURSDAY AND INTO
FRIDAY AS IT DRIFTS INTO THE GREAT BASIN. SCATTERED THUNDERSTORMS
THIS AFTERNOON AND EVENING ARE EXPECTED TO BE OF MOST CONCERN ACROSS
THE OREGON WEST SIDE. CURRENT SCATTERED THUNDERSTORMS HAVE MAINLY
BEEN IN FWZ 617, NORTHWESTERN 623, AND NORTHERN CALIFORNIA TODAY.
MODEL GUIDANCE AND TRENDS INDICATE THE UMPQUA STORMS SHOULD DRIFT
SOUTHWESTWARD THROUGH THE EVENING. UNCERTAINTY EXISTS AS TO HOW MUCH
WILL MOVE INTO 616, THOUGH ISOLATED STORMS ARE MOVING NOW. THE
CONCERN THERE IS COVERAGE COULD BECOME SCATTERED. ADDITIONALLY,
COOLER CONDITIONS DUE TO CLOUD COVER OVER NORTHERN JACKSON AND
JOSEPHINE COUNTIES MIGHT KEEP THUNDERSTORMS FROM FORMING THERE,
THOUGH MODELS INDICATE THUNDERSTORMS WILL MAKE IT INTO THESE AREAS
THIS EVENING. THUS, CONFIDENCE IS LOW TO MODERATE IN STORMS MAKING
IT INTO NORTHERN JACKSON AND JOSEPHINE COUNTIES. STORMS IN NORTHERN
CALIFORNIA ARE EXPECTED TO MIGRATE NORTHWESTWARD THROUGH THE
EVENING, INTO FWZ 282.  THESE THUNDERSTORMS WILL BRING GUSTY AND
ERRATIC WINDS, MODERATE TO LOCALLY HEAVY RAINFALL, AND THE
POSSIBILITY OF HAIL IN STORM CORES.

WITH A CONTINUED COOLING AND MOISTENING OF THE AIR MASS, WE EXPECT
LIGHTNING IGNITION POTENTIAL WILL BE LOW AFTER TODAY. RED FLAG
WARNINGS WERE SCALED BACK FOR TODAY DUE TO THE MOISTENING FUEL
CONDITIONS. FOR THURSDAY WE EXPECT THUNDERSTORMS TO BE MOSTLY ALONG
AND EAST OF THE CASCADES WITH RAIN AND CLOUD COVER POSSIBLY MOVING
WEST BETWEEN THE OREGON CASCADES AND THE COAST RANGE THURSDAY
AFTERNOON AND EVENING, WITH ONLY EMBEDDED RUMBLES.  A GRADUAL COOL
DOWN IS STILL EXPECTED THROUGH THE WEEKEND ALONG WITH SHOWERS AND
SOME ISOLATED THUNDERSTORMS. GUSTY SOUTHWEST WINDS ARE EXPECTED OVER
AND EAST OF THE CASCADES THIS WEEKEND. BTL

&&

.AVIATION...THE MAIN CONCERN TODAY WILL BE THE POTENTIAL FOR
ISOLATED TO SCATTERED THUNDERSTORMS FOR A GOOD PORTION OF THE AREA
THAT COULD AFFECT ALL TERMINALS...EXCEPT FOR NORTH BEND. THE MAIN
CONCERN WILL BE MODERATE TO HEAVY RAIN...SMALL HAIL AND GUSTY
ERRATIC OUTFLOW WINDS. VFR CONDITIONS ARE EXPECTED TO PREDOMINATE FOR
INLAND LOCATIONS, BUT TEMPORARY MVFR CIGS WITH REDUCED
VISIBILITIES ARE POSSIBLE IN SHOWERS AND THUNDERSTORMS. AT THE
COAST...MARINE STRATUS WILL PEEL AWAY INLAND TO THE COAST THIS
MORNING WITH VFR CONDITIONS EXPECTED AT NORTH BEND BETWEEN 18-19Z.
IFR CONDITIONS WILL RETURN BETWEEN 4-5Z AND CONTINUE INTO THURSDAY
MORNING. -PETRUCELLI

&&

.MARINE...UPDATED 300 PM PDT WEDNESDAY 8 JULY 2015...WEAK HIGH
PRESSURE WILL CONTINUE NORTH WINDS THROUGH EARLY THURSDAY. PATCHY
FOG AND LOW STRATUS IS EXPECTED OVER THE COAST LATE TONIGHT...AND
CLEAR LATE THURSDAY MORNING. THURSDAY AFTERNOON INTO THE WEEKEND
SOUTH TO SOUTHWEST WINDS WILL DOMINATE AS LOW PRESSURE MOVES INTO
THE PACIFIC NORTHWEST. THESE WINDS AND WIND WAVES WILL BE MODERATE
IN THE NORTHERN WATERS FRIDAY INTO THE WEEKEND...THOUGH LIKELY BELOW
ADVISORY CRITERIA. SEAS OF 4 TO 6 FEET DUE TO MIXED NORTHWEST SWELL
AND LONGER PERIOD SOUTH SWELL WILL CONTINUE THROUGH THE WEEKEND...A
THERMAL TROUGH MAY RETURN TO THE COAST WITH INCREASED NORTH WINDS
AND SHORT PERIOD SEAS AROUND TUESDAY OF NEXT WEEK. SMALL CRAFT
ADVISORY CONDITIONS ARE POSSIBLE WITH THIS THERMAL TROUGH. -MSC

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR
     ORZ617-620>623.
     FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR ORZ026-028.

CA...FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING FOR CAZ080>082.

PACIFIC COASTAL WATERS...NONE.

MAP/BTL/MSC