Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 140306
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
806 PM PDT SUN JUL 13 2014

.UPDATE...
BAND OF CIRRUS CONTINUES TO LIFT NORTH ACROSS THE FORECAST AREA
THIS EVENING AS LOWER CLOUDS ALONG THE OREGON BORDER BEGIN TO
DISSIPATE WITH LACK OF HEATING. A FEW SPOTS ARE SEEING STRONGER
SUSTAINED WINDS THROUGH THE EVENING...AND THIS...ALONG WITH THE
INCREASING HIGH CLOUDS...IS RESULTING IN A SLOWER FALL IN THE
AMBIENT TEMPERATURE THIS EVENING. LOWS MAY STAY UP A BIT MORE THAN
FORECAST OVERNIGHT IN AREAS WITH THE THICKEST HIGH CLOUDS. HEAT
ADVISORY FOR WESTERN NEVADA STILL LOOKS REASONABLE FOR MONDAY AS
HIGHS WILL CLIMB TO THE 102 TO 108 RANGE IN THE ADVISORY AREAS.
LOWS IN SOME LOWER VALLEYS MAY NOT DIP BELOW 70 TONIGHT EITHER.

WILL UPDATE TO REMOVE MENTION OF TSTMS FAR NORTH THIS EVENING...
BUT THAT IS THE ONLY SIGNIFICANT CHANGE TO THE OVERNIGHT
FORECAST. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 310 PM PDT SUN JUL 13 2014/

SYNOPSIS...
HIGH PRESSURE OVER NEVADA WILL BRING HOT CONDITIONS WITH RECORD
HIGHS LIKELY ON MONDAY. TEMPERATURES WILL DECREASE ON TUESDAY BUT
REMAIN ABOVE NORMAL THROUGH NEXT WEEKEND. MOISTURE WILL INCREASE
MONDAY WITH SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE
UPCOMING WEEK.

SHORT TERM...
FOR THE NEAR TERM, WE ARE WATCHING THE CUMULUS NEAR THE OREGON
BORDER FOR POSSIBLE VERTICAL GROWTH. SOME GUIDANCE HAS HINTED AT
THE CAP WEAKENING ENOUGH TO PRODUCE ISOLATED CONVECTION BETWEEN 3
AND 7 PM. WE ADDED A SLIGHT CHANCE OF THUNDER NORTH OF CEDARVILLE,
ALTHOUGH THIS POTENTIAL IS MARGINAL.

OTHERWISE, THE MAIN WEATHER HIGHLIGHTS WILL BE CONTINUED HOT
CONDITIONS THROUGH MONDAY, AND INCREASING THUNDERSTORM THREAT FOR
THE NEXT SEVERAL DAYS.

STRONG HIGH PRESSURE OVER NEVADA WILL KEEP TRIPLE DIGIT HEAT GOING
THROUGH MONDAY, WITH THE HEAT ADVISORY REMAINING IN PLACE FOR THE
RENO-CARSON VICINITY EASTWARD ACROSS LOVELOCK AND FALLON. THERE IS
STILL A POSSIBILITY OF MID-HIGH LEVEL CLOUD COVER HOLDING BACK MAX
TEMPS A COUPLE OF DEGREES ESPECIALLY FOR FAR WESTERN NV, BUT IT
WOULD TAKE A RATHER THICK CLOUD DECK TO PREVENT VALLEY TEMPS FROM
SURPASSING 100 DEGREES. OVERNIGHT TEMPS ARE STILL LIKELY TO REMAIN
ABOVE 70 DEGREES FOR AT LEAST THE NEXT COUPLE OF NIGHTS, ESPECIALLY
IN URBAN VALLEYS AND AREAS WHERE CLOUD COVER IS MORE WIDESPREAD.
GUIDANCE IS IN GOOD AGREEMENT WITH MORE SIGNIFICANT CLOUD COVER AND
COOLING 700 MB TEMPS ON TUESDAY, WITH ONLY ISOLATED LOCATIONS
REACHING 100 DEGREES.

INCREASING MOISTURE AND HEATING WILL PRODUCE UNSTABLE CONDITIONS
BOTH MONDAY AND TUESDAY. WEAK STEERING FLOW IS EXPECTED BOTH DAYS
SO EVEN IF STORMS INITIALLY HAVE HIGH CLOUD BASES AND PRODUCE
LIGHTNING OUTSIDE THE MAIN PRECIP CORES, THEY SHOULD QUICKLY
BECOME RAIN PRODUCERS DUE TO LITTLE TO NO CELL MOTION WITH
PRECIPITABLE WATER VALUES INCREASING ABOVE 0.80 INCH MONDAY
AFTERNOON. THE BEST THUNDERSTORM POTENTIAL IS EXPECTED NEAR THE
SIERRA, WITH MORE ISOLATED CELLS IN NORTHEAST CA-WESTERN NV.
NAM/GFS GUIDANCE INDICATED DOWNDRAFT CAPE VALUES NEAR 1000 J/KG,
WHICH WOULD YIELD POTENTIAL OUTFLOW GUSTS NEAR 60 MPH FOR
THUNDERSTORMS THAT OCCUR IN LOWER ELEVATIONS.

FOR TUESDAY, PRECIPITABLE WATER VALUES INCREASE FURTHER TO NEAR
1.0 INCH. CONVECTIVE TEMPERATURES WILL BE LOWER SO SOME CELLS
COULD DEVELOP BEFORE NOON WITH THE BEST CHANCE FOR STORM FORMATION
AGAIN NEAR THE SIERRA. HOWEVER, IN THESE TYPE OF HIGH MOISTURE
SCENARIOS WHEN DYNAMIC FORCING IS LIMITED, THERE IS A POTENTIAL
INHIBITING FACTOR OF TOO MUCH CLOUD COVERAGE LIMITING INSTABILITY,
WHICH WOULD RESULT IN MAINLY SHOWERS AND FEWER THUNDERSTORMS.

SOME SHOWERS COULD LINGER IN THE MOIST ENVIRONMENT BOTH MONDAY
NIGHT AND TUESDAY NIGHT. A FEW OVERNIGHT THUNDERSTORMS ARE ALSO
POSSIBLE, ALTHOUGH LIMITED FORCING AND ABSENCE OF SIGNIFICANT
SHORTWAVES ROTATING AROUND THE RIDGE WILL KEEP THIS POTENTIAL
RATHER SLIM. MJD

LONG TERM...WEDNESDAY THROUGH SUNDAY...

NO MAJOR CHANGES TO THUNDERSTORM POTENTIAL OR TEMPERATURES; ONLY
MINOR ADJUSTMENTS BASED ON NEWEST GUIDANCE. DID MAKES SOME CHANGES
TOWARDS THE END OF THE WEEK AND WEEKEND IN REGARDS TO WINDS.

MID RANGE MODELS REMAIN IN RELATIVELY GOOD AGREEMENT THROUGH THE
END OF THE WEEK. PWATS WILL REMAIN ELEVATED AROUND 1 INCH THROUGH
FRIDAY FOR AREAS ALONG AND SOUTH OF I-80, THEN MAINLY SOUTH OF
HIGHWAY 50 SATURDAY INTO SUNDAY. THESE AREAS WILL CARRY THE BEST
CHANCES WITH SCATTERED THUNDERSTORMS. OTHERWISE, WEDNESDAY WILL
HAVE AT LEAST ISOLATED CHANCES AREA-WIDE WITH SHOWERS ALONG THE
SIERRA OVERNIGHT. AS FOR THE CHARACTER OF THE STORMS, THEY WILL
GENERALLY BE WET ESPECIALLY IN AREAS OF SCATTERED COVERAGE. CORES
WILL BE SMALLER FOR ISOLATED COVERAGE, BUT CELL MOTION WILL BE
LACKING. EXPECT SOME HYBRIDIZATION CHANGING FROM DRY TO MOSTLY
MOIST AS STORM CELLS MODIFY THE SURROUNDING ENVIRONMENT. ALSO OF
CONCERN WITH THESE STORMS, GUSTY OUTFLOWS WILL BE POSSIBLE WITH
TEMPERATURES REMAINING IN THE MID TO UPPER 90S.

SOUTHWEST FLOW BEGINS TO DEEPEN LATE IN THE WEEK AS TROUGHING DIGS
SOUTH IN THE CENTRAL PLAINS CAUSING THE LONG WAVE PATTERN TO
RETROGRADE. THIS WILL TIGHTEN THE SURFACE PRESSURE GRADIENT
ENHANCING AFTERNOON ZEPHYRS. HAVE BEGUN TO INCREASE WIND SPEEDS FOR
SATURDAY. THIS COULD HERALD A PERIOD OF CRITICAL FIRE WEATHER
CONDITIONS WITH HUMIDITY BELOW 15% DURING THE AFTERNOON. BOYD

AVIATION...

WINDS WILL GENERALLY BE LIGHT WITH HOT, NEAR RECORD TEMPERATURES
ONCE AGAIN FOR MONDAY. MOISTURE BEGINS TO INCREASE MONDAY WITH
ISOLD-SCT TSTMS WITH WIND GSTS TO 45 KTS AND LOCALLY HEAVY RAIN
POSSIBLE. DEEP MOISTURE TO BE IN PLACE MOST OF THE WEEK THEREAFTER
WITH SCT TSTMS WHERE HEAVY RAINFALL THE BIGGEST THREAT. AFTERNOON
WINDS BECOME BREEZY LATE IN THE WEEK AND OVER THE WEEKEND.
WALLMANN/BOYD

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...HEAT ADVISORY UNTIL 6 PM PDT MONDAY BELOW 5000 FEET FOR
     NVZ003-004.

CA...NONE.
&&

$$

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





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