Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 110310
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
810 PM PDT THU JUL 10 2014

.UPDATE...
CONVECTION OVER THE FORECAST AREA NEVER BECAME AS WIDESPREAD AS
ORIGINALLY FORECAST THIS EVENING. THERE REMAINS RESIDUAL CONVECTION
MAINLY ACROSS THE BASIN AND RANGE OF WESTERN NEVADA...BUT A FEW
SHOWERS ARE STILL NOTED OVER ERN CA FROM PORTOLA NORTHWARD AND
ALONG THE SIERRA CREST IN MONO COUNTY. LARGE UPPER LOW REMAINS OFF
THE COAST AND HAS A JET STREAK ROTATING AROUND ITS BASE. LATEST
FORECAST MODEL GUIDANCE STILL HAS THIS JET STREAK AND MID LVL
TROUGH MOVING UP THROUGH THE REGION LATE TONIGHT AND EARLY FRIDAY.
FOR NOW IT APPEARS THE BEST CHANCE FOR TSTMS WILL BE JUST WEST OF
THE REGION INTO CENTRAL AND NORTH CENTRAL CA...BUT WE SHOULD STILL
SEE A LITTLE DEVELOPMENT OVERNIGHT IN NE CA. THIS ACTIVITY WOULD
LIKELY BE ELEVATED AND THUS THE POTENTIAL FOR DRY LIGHTNING
STRIKES REMAINS.

WILL UPDATE THIS EVENING TO ADJUST TSTM COVERAGE THROUGH 06
UTC...BUT NO REAL CHANGES AFTER THAT POINT. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 242 PM PDT THU JUL 10 2014/

SYNOPSIS...
ISOLATED TO SCATTERED THUNDERSTORMS FOR THE SIERRA AND WESTERN
NEVADA THROUGH THIS EVENING MAY CONTINUE NORTH OF HIGHWAY 50
THROUGH THE NIGHT. A FEW STORMS ARE AGAIN POSSIBLE FROM NEAR
INTERSTATE 80 NORTH ON FRIDAY BEFORE HIGH PRESSURE STRENGTHENS
OVER THE WEEKEND FOR DRIER AND HOTTER CONDITIONS.

SHORT TERM...
INCREASED COVERAGE FOR THUNDERSTORMS FRIDAY AFTERNOON, OTHERWISE
NO SUBSTANTIAL CHANGE TO FORECAST THINKING IN THE SHORT TERM.

ISOLATED-SCATTERED THUNDERSTORMS HAVE DEVELOPED IN THE SIERRA
SOUTH OF HIGHWAY 50 AND OUT IN THE BASIN OF MINERAL AND EASTERN
CHURCHILL COUNTIES. THUNDERSTORMS SHOULD INCREASE IN COVERAGE AND
INTENSITY AS THEY MOVE NORTH AND TAP INTO A WELL-HEATED ENVIRONMENT
TO AID INSTABILITY. WITH LIGHT SOUTHERLY STEERING FLOW OF 5-10 KTS
ALONG WITH PRECIPITABLE WATER VALUES AROUND 0.75 OF AN INCH
(MEASURED IN RENO), LOCALLY HEAVY RAINFALL IS THE MAIN CONCERN
ESPECIALLY IF STORMS TRAIN OR HIT AREAS THAT RECEIVED HEAVY
RAINFALL TUESDAY. SECONDARY CONCERNS INCLUDE WINDS AND BLOWING
DUST FOR THE LOWER ELEVATIONS, WITH GUSTS 45-50 MPH FOR STRONGER
THUNDERSTORMS ALONG WITH LOCAL VISIBILITIES BELOW 2 MILES DOWNWIND
OF DRY LAKE BEDS.

TONIGHT, UPPER FORCING ARRIVES LATE TONIGHT AHEAD OF A NEGATIVELY-
TILTED TROUGH OFF THE CALIFORNIA COAST. THE GFS/NAM/SREF CONTINUE
TO SHOW SOME POTENTIAL FOR ISOLATED TO SCATTERED NOCTURNAL
THUNDERSTORMS OVER NORTHEAST CALIFORNIA AND NORTHWEST NEVADA,
ALTHOUGH THE LARGEST LIGHTNING THREAT COULD BE WEST OF THE SIERRA
AND WARNER MOUNTAIN CRESTS PER SOME GUIDANCE. ONE POSSIBLE OUTCOME
IS THAT TODAY`S THUNDERSTORMS CONTINUE AFTER SUNSET AS A CONVECTIVE
COMPLEX WHICH WORKS NORTH THROUGH EASTERN CALIFORNIA OVERNIGHT.
THERE IS A FIRE CONCERN RELATED TO DRY LIGHTNING OVER NORTHEAST
CALIFORNIA NORTH OF TAHOE TONIGHT AND FRIDAY MORNING SO SEE THE
FIRE WEATHER DISCUSSION FOR MORE DETAILS.

FRIDAY, THE MAIN UPPER FORCING/JET NOSE SLIDES INTO EXTREME NORTHERN
NEVADA AND SOUTHEAST OREGON BETWEEN MID MORNING AND EARLY AFTERNOON.
MODELS HAVE SLOWED DOWN WITH THE PASSAGE OF THE FORCING WHICH HAS
RESULTED IN THUNDERSTORM CHANCES POPPING UP FURTHER SOUTH THAN BEFORE.
IN FACT, THE 18Z NAM BRINGS THE POSSIBILITY ALL THE WAY SOUTH INTO
MONO COUNTY. A PRO FOR AT LEAST ISOLATED STORMS WILL BE THAT MOISTURE
IS NOT EXPECTED TO BE SCOURED SIGNIFICANTLY DUE TO CONTINUED SOUTHERLY
FLOW ALOFT BEHIND THE NEGATIVELY-TILTED SHORT WAVE. ON THE CON SIDE,
SHEAR ALOFT MAY INCREASE BEYOND WHAT THE AVAILABLE INSTABILITY/CAPE
CAN HANDLE BY FRIDAY AFTERNOON. FOR NOW, I DRAGGED SLIGHT CHANCES
DOWN TO AROUND INTERSTATE 80 IN WESTERN NEVADA AND INCREASED CLOUD
COVER SOME.

SATURDAY, DRIER AND MORE STABLE AIR INVADES THE REGION AS A FOUR
CORNERS RIDGE BUILDS WEST INTO CALIFORNIA AND NEVADA. TEMPERATURES WILL
TOP OUT NEAR OR SLIGHTLY ABOVE AVERAGE SATURDAY AFTERNOON. IT IS
UP FROM THERE IN THE LONG TERM! SNYDER

LONG TERM...SUNDAY THROUGH THURSDAY...
HIGH PRESSURE WILL REMAIN OVER THE WEST THROUGH MOST OF NEXT WEEK
WITH VERY HOT CONDITIONS TO START THE WEEK WITH AN INCREASING THREAT
FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH THURSDAY.

WITH THE HIGH CENTERED OVER NEVADA SUNDAY AND MONDAY, AFTERNOON
HIGHS MAY SOAR TO RECORD LEVELS. LATEST FORECASTS SUGGEST 100-110
FOR THE NEVADA VALLEYS WITH 85-95 FOR THE SIERRA. RECORDS AT THE
RENO AIRPORT ARE 102 ON SUNDAY AND 103 ON MONDAY, BOTH SET IN 1972.
GIVEN THE POTENTIAL TWO DAY HEAT WAVE, THERE IS A POSSIBILITY A HEAT
ADVISORY MAY BE REQUIRED FOR THE NEVADA VALLEYS IN THE NEXT DAY OR
TWO BASED ON MODEL CONSISTENCY.

THUNDERSTORM POTENTIAL WILL BEGIN ON MONDAY AS MOISTURE START TO
CREEP NORTHWARD INTO MONO, MINERAL, ALPINE AND SOUTHERN LYON
COUNTIES. FOR MONDAY, IS STORMS DEVELOP THEY WILL LIKELY BE HIGH
BASED, SO BIGGEST THREAT IS STRONG OUTFLOW WINDS AND DRY LIGHTNING
STRIKES.

MOISTURE MAY INCREASE RAPIDLY ON TUESDAY AS ACROSS THE ENTIRE AREA
WITH SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THURSDAY.  STORMS
WILL HAVE A HIGHER POTENTIAL TO PRODUCE HEAVY RAIN, WITH GUSTY
OUTFLOWS POSSIBLE BY MID WEEK. BRONG

AVIATION...
THUNDERSTORMS WILL CONTINUE THIS EVENING FOR MOST AREAS WITH A FEW
STORMS PERSISTING THROUGH TONIGHT AND EARLY FRIDAY MORNING NORTH
OF KTRK-KRNO-KLOL. MAIN THREAT FROM STORMS IS MODERATE TO HEAVY
RAIN, HAIL AND OUTFLOW WINDS TO 45 KTS.

THUNDERSTORMS CHANCES WILL BE LIMITED ON FRIDAY TO AREAS NORTH OF
KTRK-KRNO-KLOL MAIN THREAT IS OUTFLOW WINDS TO 35-40KTS.

NO THUNDERSTORMS AND LIGHT WINDS ARE FORECAST FOR SATURDAY AND
SUNDAY. HOWEVER THERE IS A GOOD CHANCE THUNDERSTORMS WILL RETURN TO
THE AREA FOR MOST OF NEXT WEEK. BRONG

FIRE WEATHER...

..RED FLAG WARNING FOR THUNDERSTORMS AND STRONG OUTFLOW WINDS IN
EFFECT TONIGHT AND FRIDAY MORNING FOR THE NORTHEASTERN SIERRA AND
NORTHEASTERN CALIFORNIA...

DEEP MOISTURE AND INSTABILITY IN THE REGION WILL KEEP SHOWERS AND
THUNDERSTORMS GOING WELL INTO THE EVENING MAINLY SOUTH OF INTERSTATE
80. STORMS WILL BE MOSTLY WET THROUGH THE EVENING WITH GOOD
POTENTIAL FOR WETTING RAINS. BY TONIGHT, THE FOCUS WILL SHIFT NORTH
AND EAST AS THE UPPER LEVEL DISTURBANCE MOVES OVER NORTHERN CA.

GOOD INSTABILITY ALOFT, STEEP UPPER LEVEL LAPSE RATES, AND FORCING
FROM THE MID AND UPPER-LEVEL WAVE WILL KICK OFF ELEVATED
THUNDERSTORMS OVERNIGHT AND INTO FRIDAY MORNING. STORMS WILL BE A
MIX OF WET AND DRY, AS PRECIPITABLE WATER INCREASES TO OVER 0.80".
BUT AS THE WAVE PUSHES INLAND, THE MIDLEVEL STEERING FLOW WILL
INCREASE TO OVER 30KTS. THIS INCREASED STORM SPEED WILL ALLOW FOR
LESS RAINFALL OVERALL AND HIGHER POTENTIAL FOR DRY LIGHTNING
STRIKES. RED FLAG WARNING IS IN EFFECT FOR TONIGHT AND FRIDAY
MORNING FOR AREAS NORTH OF TAHOE IN NORTHEASTERN CALIFORNIA AND THE
NORTHEAST SIERRA.

THERE IS SOME UNCERTAINTY IN THE FORECAST, INCLUDING THE AREA OF
HIGHEST LIGHTNING COVERAGE. THINKING THAT THE HIGHEST PROBABILITY
WILL BE NEAR THE SIERRA CREST NORTH OF TAHOE AND UP INTO THE LASSEN
PARK AREA, ALTHOUGH THAT COULD SHIFT EAST OR WEST BY AS MUCH AS 50
MILES.

BY FRIDAY, AFTERNOON CONVECTION WILL AGAIN DEVELOP IN NORTHWEST
NEVADA AND NORTHEAST CA. THESE STORMS WILL BE A MIX OF WET AND DRY
STORMS AS WELL, AS MID LEVEL FLOW REMAINS STRONGER. HOON

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...RED FLAG WARNING UNTIL 11 AM PDT FRIDAY CAZ271-278.

&&

$$

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







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