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000
FXUS65 KREV 292124
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
224 PM PDT TUE JUL 29 2014

.SYNOPSIS...
ABUNDANT MOISTURE WILL CONTINUE PUSHING NORTH THROUGH THE WEEK.
AN UPPER LEVEL DISTURBANCE LIFTS NORTHEAST OVER THE REGION
WEDNESDAY AND INTERACTS WITH DEEP MOISTURE TO PRODUCE LOCALLY
HEAVY RAIN, AND EVEN THE POTENTIAL FOR FLASH FLOODING FROM MONO
COUNTY NORTH AND EAST INTO MINERAL, CHURCHILL AND PERSHING
COUNTIES. FASTER STORM MOTIONS BY THURSDAY COULD RESULT IN GUSTY
OUTFLOW WINDS ALONG WITH A FEW DRY LIGHTNING STRIKES, MAINLY OVER
THE NORTHERN PART OF THE FORECAST AREA, WHILE LOCALLY HEAVY RAINS
AREA POSSIBLE SOUTH OF INTERSTATE 80.

&&

.SHORT TERM...
PARTIAL CLEARING OVER THE SOUTHERN PART OF THE FORECAST AREA ALLOWED
HEATING EARLY IN THE AFTERNOON AND THUNDERSTORMS HAVE DEVELOPED
ALONG THE SIERRA CREST SOUTH OF HIGHWAY 50. THESE STORMS SHOULD
BEGIN TO DRIFT OFF THE TO THE EAST AND REDEVELOP WITH LOCALLY HEAVY
RAIN POSSIBLE IN ISOLATED AREAS. ADDITIONAL STORMS HAVE FORMED
OVER THE FAR NORTHWEST PORTION OF THE CWA. THESE STORMS SHOULD
DRIFT NORTHEAST THROUGH THE LATE AFTERNOON AND EARLY EVENING. WITH
CLOUDS INHIBITING CONVECTION THUS FAR OVER THE CENTRAL AND EASTERN
PORTIONS OF THE CWA...IT IS POSSIBLE THAT MANY AREAS IN THE BASIN
AND RANGE WILL SEE FEW...IF ANY STORMS THIS EVENING.

THE MODELS CONTINUE TO STRUGGLE WITH SUBTLE FEATURES EMBEDDED IN
THE OVERALL FLOW...BUT THE GFS HAS BEEN MORE CONSISTENT WITH A
VORTICITY LOBE THAT IS A REMNANT OF A TROPICAL SYSTEM LIFTING
NORTH TOWARD SOUTHERN CA THIS AFTERNOON. THIS LOBE SHOULD LIFT
NORTHEAST TOMORROW OVER THE SOUTHERN HALF OF THE FORECAST AND
PROVIDE THE MAIN FORCING FOR ORGANIZED STORMS ACROSS THE SOUTHERN
HALF OD THE REGION. FORECAST SOUNDINGS FROM MONO COUNTY NORTHEAST
THROUGH MINERAL AND CHURCHILL COUNTIES SHOW PWATS APPROACHING 1
INCH FOR WEDNESDAY WITH RELATIVELY LIGHT STORM MOTIONS. WHILE
INSTABILITY IS NOT OVERWHELMING...THE LACK OF STORM MOTION AND THE
PRESENCE OF MID LVL FORCING SHOULD BE ENOUGH TO PRODUCE LOCALLY
HEAVY RAINS EAST OF A LINE FROM BRIDGEPORT TO YERINGTON TO FALLON
TO NEAR WINNEMUCCA. A FLASH FLOOD WATCH FOR MONO...
MINERAL...SOUTHERN LYON AND THE EASTERN 2/3RDS OF CHURCHILL AND
PERSHING COUNTIES WILL BE IN EFFECT FOR WEDNESDAY AFTERNOON AND
EVENING.

OUTSIDE OF THE WATCH AREA STORM MOTIONS WILL BE A LITTLE FASTER...
BUT LOCALLY HEAVY RAIN IS POSSIBLE...JUST NOT EXPECTED TO BE AS
PROBABLE. AREAS OF STEEPER TERRAIN AND RECENT BURN SCARS IN
ALPINE...DOUGLAS...STOREY AND NORTHERN LYON COUNTIES WILL BE
ESPECIALLY SUSCEPTIBLE TO RUN OFF FROM HEAVY RAINS WEDNESDAY.

THE PRESENCE OF THE MID LEVEL FORCING WILL MEAN A CONTINUED THREAT
OF THUNDERSTORMS IN THE SOUTHERN AND EASTERN AREAS WEDNESDAY
NIGHT.

ADDITIONAL FORCING FROM ANOTHER VORTICITY LOBE SHOULD PRODUCE
THUNDERSTORMS AGAIN THURSDAY. THESE ARE LIKELY TO BE MOVING A
LITTLE FASTER OVERALL...BUT AGAIN THE SLOWEST MOTIONS WILL BE
ACROSS THE SOUTHERN AND EASTERN 1/3RD OF THE FORECAST AREA. OVER
NORTHERN PORTIONS THE STORMS ARE LIKELY TO BE MOVING FASTER WITH
DRIER SUB CLOUD LAYERS THAT COULD PRODUCE VERY GUSTY OUTFLOW
WINDS. DRY LIGHTNING STRIKES ARE ALSO A STRONG POSSIBILITY FOR THE
NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA THURSDAY. 20

.LONG TERM...FRIDAY THROUGH TUESDAY...
MOISTURE AND INSTABILITY REMAIN IN THE FORECAST INTO NEXT WEEK.
HIGH PRESSURE PREVAILS OVER THE SOUTHWEST US WITH A WEAK TROUGH
DEVELOPING NEAR THE CA COAST THIS WEEKEND. BY EARLY NEXT WEEK,
THIS TROUGH MAY DISSIPATE OR MOVE FARTHER OFFSHORE, RESULTING IN
MORE UNCERTAINTY IN THUNDERSTORM POTENTIAL. HIGH TEMPERATURES WILL
REMAIN SLIGHTLY ABOVE NORMAL, MAINLY IN THE 90S FOR THE LOWER
ELEVATIONS AND 80S IN THE SIERRA.

FOR FRIDAY AND SATURDAY, SOUTHWEST FLOW ALOFT APPEARS TO BE
SUFFICIENT TO KEEP CONVECTION OUT OF THE NORTHERN SIERRA AND TAHOE
BASIN, WITH BETTER THUNDERSTORM POTENTIAL IN WESTERN NEVADA EAST OF
RENO AND CARSON CITY. ON TODAY`S GUIDANCE, THE TROUGH IS LOCATED
NEAR OR JUST INLAND OVER NORTHWEST CALIFORNIA FOR BOTH DAYS. FOR
AREAS SOUTH OF HIGHWAY 50, THERE MAY BE OTHER DISTURBANCES ROTATING
AROUND THE RIDGE THAT WILL AFFECT CONVECTIVE POTENTIAL, BUT THEY
APPEAR TO BE TRACKING TOO FAR SOUTH AND EAST TO HAVE MUCH EFFECT ON
THESE AREAS.

ON SUNDAY, MODEL GUIDANCE IS HAVING DIFFICULTY KEEPING THE TROUGH
NEAR CALIFORNIA INTACT, WITH MUCH OF THE ENERGY BEING SHEARED OUT TO
THE NORTH AND EAST. IF THIS OCCURS, THEN THUNDERSTORM POTENTIAL
WOULD LIKELY DECREASE. PREVIOUS DAYS OF GUIDANCE WERE FAVORING THIS
TROUGH HOLDING TOGETHER AND DRIFTING SLOWLY SOUTH ALONG THE CA
COAST, BRINGING IN MORE SOUTHERLY FLOW ALOFT AND RESTORING
THUNDERSTORM CHANCES TO THE NORTHERN SIERRA AND TAHOE BASIN. AT THIS
TIME WE WILL KEEP A MENTION OF THUNDER IN ALL AREAS, ALTHOUGH WE DID
PUSH THE BETTER CHANCES TO THE EAST OF RENO-CARSON CITY.

FOR MONDAY AND TUESDAY, EVEN MORE UNCERTAINTY EXISTS FOR THE WEATHER
PATTERN OVER CA-NV. THE LATEST GUIDANCE IS ERODING THE GREAT BASIN
PORTION OF THE RIDGE, WHILE THE REMNANT TROUGH NEAR THE CALIFORNIA
COAST DRIFTS FARTHER OFFSHORE WITH MINIMAL EFFECTS FOR THE SIERRA
OR WESTERN NV. SINCE THERE IS NO DISTINCT MECHANISM CLEARING OUT
THE MOISTURE AND INSTABILITY, WE WILL KEEP A MENTION OF THUNDER IN
OUR REGION, BUT CONFIDENCE IS NOT SUFFICIENT TO GO ABOVE SLIGHT
CHANCE IN ANY LOCATION.

ISOLATED SHOWERS AND EMBEDDED THUNDERSTORMS FROM RESIDUAL MOISTURE
OR CONVECTIVE OUTFLOW INTERACTIONS ARE ALSO POSSIBLE FOR THE
OVERNIGHT HOURS, MAINLY FOR NORTHEAST CA-NORTHWEST NV. MJD
&&

.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS EAST OF THE SIERRA CREST ARE
LIKELY TO PROPAGATE EAST INTO FAR WESTERN NV THRU LATE AFTERNOON.
HAVE MENTIONED AT LEAST VCTS IN ALL TERMINALS THRU 00Z AROUND
THE TAHOE BASIN, AND THRU 02Z FROM KRNO-KCXP TO KMMH. SHORT RANGE
GUIDANCE INDICATES ACTIVITY WINDING DOWN RATHER QUICKLY BY EARLY
EVENING. BRIEF HEAVY RAIN AND OUTFLOW WIND GUSTS TO 30 KT ARE
POSSIBLE WITH THE GUSTY WINDS MORE LIKELY AFFECTING LOWER ELEVATIONS
OF WESTERN NV.

FOR WEDNESDAY, ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE
EXPECTED MAINLY BTWN 19Z-04Z, WITH GREATER COVERAGE AND HEAVY
RAINFALL POTENTIAL SOUTH AND EAST OF WINNEMUCCA-FALLON-BRIDGEPORT
LINE. MJD
&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
     EVENING NVZ004.

     FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
     EVENING NVZ001.

CA...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
     EVENING CAZ073.

&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)