Flash Flood Watch 6, NWS Elko, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ELKO NV
200 PM PDT WED JUL 30 2014

.SYNOPSIS...MONSOON MOISTURE WILL PERSIST ACROSS NEVADA KEEPING
SHOWERS AND THUNDERSTORMS IN THE FORECAST EACH AFTERNOON AND
EVENING THROUGH THE WEEKEND AND EARLY NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY.

ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS DEVELOPING THIS
AFTERNOON ACROSS NEVADA, WITH CAPE NEAR 500 J/KG AND LIFTED INDEX
OF -1 TO -3. PW AND MOISTURE CONTENT HAVE DECREASED A BIT FROM
PREVIOUS DAYS, FALLING TO ABOUT 0.80 INCH. 12Z GFS SUGGESTS
PRECIPITABLE WATER WILL DEGRADE FURTHER TO NEAR 0.75 INCH THROUGH
THIS EVENING, SUGGESTING THE THREAT FOR HEAVY RAINFALL WILL BE
REDUCED (OR AT LEAST MORE LOCALIZED) AND SOME DRY LIGHTNING
STRIKES ARE MORE APT TO OCCUR OUTSIDE OF RAIN CORES. 12Z NAM
SUGGESTS CLOUDS AND SHOWERS, WITH ISOLATED THUNDER, WILL CONTINUE
TONIGHT AHEAD OF TROPICAL REMNANTS FROM THE PACIFIC APPROACHING
FROM THE SW. INCREASED CLOUD COVER AND LOW TEMPERATURES THURSDAY
MORNING A FEW DEGREES, AND KEPT A MENTION OF ISOLATED THUNDER
DURING THE CONVECTIVE MIN LATE NIGHT/EARLY MORNING HOURS.

THURSDAY...REMNANTS OF EASTERN PACIFIC TROPICAL SYSTEM WILL ROTATE
NORTHEAST THROUGH NEVADA. ASSOCIATED DYNAMIC LIFT EXPECTED TO
COINCIDE WITH PEAK AFTERNOON HEATING, AND THUNDERSTORM COVERAGE
WILL INCREASE AS A RESULT. GFS CRANKS UP PRECIPITABLE WATER
SIGNIFICANTLY AS THIS WAVE PASSES, WITH FORECAST SOUNDINGS PLACING
PW OF 1.1 INCH AT ELKO THURSDAY EVENING. 12Z NAM/GFS BOTH FORECAST
WIDESPREAD INSTABILITY SUFFICIENT FOR CONVECTION, AND STORM MOTION
AGAIN WILL BE SLOW/STATIONARY AND ERRATIC, WITH 700 MB FLOW OF 0-5
KTS. INCREASED THUNDERSTORM COVERAGE IN THE GRIDS, MENTIONED HEAVY
RAIN, AND ISSUED ANOTHER FLASH FLOOD WATCH FROM NOON THROUGH 9 PM.
CONFIDENCE FOR LOCALLY HEAVY RAINFALL IS GREATEST ACROSS EASTERN
AND CENTRAL NEVADA, SO KEPT HUMBOLDT COUNTY OUT OF THE FLASH FLOOD
WATCH FOR NOW, BUT FORECAST SHIFT TONIGHT WILL NEED TO REEXAMINE
THIS.

CLOUDS AND THUNDERSTORMS WILL KEEP MOST VALLEYS IN THE 80S ON
THURSDAY, EVEN SOME UPPER 70S ACROSS CENTRAL NEVADA. FURTHER FROM
THE MOISTURE SURGE, EXPECTING LOWER 90S IN HUMBOLDT COUNTY.

FRIDAY...TROPICAL WAVE AND ITS VERY HIGH PW PHASE EAST OF NEVADA,
WITH MOISTURE CONTENT AGAIN DECREASING A BIT. GFS PW FALLS AGAIN
TO 0.75-0.80 INCH, WITH LESS THREAT OF FLASH FLOODING. STILL
ENOUGH MOISTURE TO SUPPORT CONVECTION, AND NAM/GFS BOTH SPREAD
WIDESPREAD INSTABILITY ACROSS THE CWA FRIDAY AFTERNOON AND
EVENING. FORCING WILL BE WEAKER COMPARED TO THURSDAY, SO WENT WITH
SCATTERED THUNDERSTORM COVERAGE (30%) FOR MOST ZONES. WITH LESS
CLOUD COVER, FRIDAY'S MAX TEMPS EXPECTED TO WARM 2-5 DEGREES OVER
THURSDAY'S READINGS.

TURNER

.LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY. STILL LOOKS LIKE
AN ACTIVE WEATHER PATTERN FOR THE CWA THROUGH THE PERIOD AS THE
AIRMASS REMAINS UNSTABLE AND FAIRLY MOIST. FOR FRIDAY NIGHT INTO
SATURDAY...THERMAL TROF SHIFTS INTO CENTRAL NEVADA WHICH IS EXPECTED
TO PRODUCE SHOWERS AND THUNDERSTORMS OVER THE ENTIRE CWA. HAVE KEPT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE FORECAST AS
PRECIPITABLE WATER VALUES INCREASE ONCE AGAIN TO 0.75 TO 0.90 INCHES
OVER THE MAJORITY OF THE FORECAST AREA. FOR SUNDAY THROUGH NEXT
WEDNESDAY...HAVE KEPT THE THREAT FOR ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS IN THE FORECAST EACH AFTERNOON...WITH
SOME TSTM ACTIVITY AT NIGHT. HOWEVER...SOME DRY AIR MAY MOVE IN OVER
EXTREME WESTERN HUMBOLDT COUNTY DURING THE LATER PERIODS.

&&

.AVIATION...ISOLATED THUNDERSTORMS NEAR THE TAF SITES EARLY THIS
EVENING...THEN DISSIPATING BY 03Z. THUNDERSTORM ACTIVITY WILL
DEVELOP AGAIN THURSDAY AS THE AIRMASS REMAINS UNSTABLE AND MOIST.

&&

.FIRE WEATHER...SCATTERED CONVECTION INTO THIS EVENING WITH LAL OF
4. REMNANTS OF A PACIFIC TROPICAL SYSTEM WILL ENHANCE THUNDERSTORM
COVERAGE THURSDAY, WITH SCATTERED TO NUMEROUS COVERAGE, AND AN LAL
OF 5 ACROSS PORTIONS OF EASTERN NEVADA. LOCALLY HEAVY RAINFALL AND
FLASH FLOODING ARE POSSIBLE THURSDAY AFTERNOON AND EVENING.
MOISTURE QUALITY DECREASES SOME FRIDAY, BUT STILL EXPECTING
SCATTERED CONVECTION TO REDEVELOP AFTER NOON FRIDAY, WITH LAL OF
4. EXPECTING A MIX OF WET/DRY STORMS ACROSS NORTHERN NEVADA
THROUGH THIS EVENING, WITH PW NEAR 0.75 INCH, WHERE SOME DRY
LIGHTNING STRIKES ARE EXPECTED OUTSIDE OF RAIN CORES. STORMS WILL
TREND TOWARD ALL WET THURSDAY, AS PW CLIMBS TO NEAR ONE INCH.
RAINFALL EFFICIENCY OF STORMS WILL AGAIN DECREASE SOME ON FRIDAY,
AS PW FALLS BACK TO 0.75-0.80 INCH. WINDS WILL BE LIGHT OUTSIDE OF
CONVECTION, BUT AS ALWAYS, STRONGEST STORMS WILL PRODUCE ERRATIC
OUTFLOW WINDS OF 40-50 MPH.

TURNER

&&

.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR NORTHEASTERN NYE COUNTY...NORTHERN ELKO COUNTY...
NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY...NORTHWESTERN
NYE COUNTY...RUBY MOUNTAINS/EAST HUMBOLDT RANGE...SOUTH CENTRAL
ELKO COUNTY...SOUTHEASTERN ELKO COUNTY...SOUTHERN LANDER COUNTY
AND SOUTHERN EUREKA COUNTY...SOUTHWESTERN ELKO COUNTY...WHITE
PINE COUNTY.

&&

99/87/87/99