Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 230307
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
807 PM PDT FRI MAY 22 2015

.UPDATE...
PRIMARY UPPER LOW CONTINUES TO PULL VERY SLOWLY AWAY TO EAST
SOUTHEAST TONIGHT BUT INSTABILITY ON THE BACK SIDE OF THIS LOW
BOOSTED BY A WEAK VORTICITY LOBE IS KEEPING SHOWERS AND A FEW
THUNDERSTORMS GOING OVER THE SRN 2/3RDS OF THE FORECAST AREA THIS
EVENING. ACTIVITY ACROSS THE FAR NORTH IS TAPERING AT THIS TIME
BUT LATEST MODEL GUIDANCE SHOWS A SECONDARY AREA OF LOW PRESSURE
DROPPING SOUTH LATE TONIGHT INTO SATURDAY AND BRINGING SHOWERS
BACK INTO THE PICTURE. WILL TRIM THE POPS BACK JUST A LITTLE FOR
NRN AREAS LATE THIS EVENING THEN SHOW A SLIGHT DECREASE FROM THE
PREVIOUS FORECAST OF CONVECTIVE COVERAGE OVER THE SRN HALF BY SAT
MORNING. WILL KEEP ISOLATED THUNDER WORDING IN THE FORECAST SOUTH
OF A LOVELOCK TO COLEVILLE LINE THIS EVENING. THIS AREA IS CLOSER
TO THE CORE OF THE UPPER LOW AND THUS HAS A BIT BETTER MID LEVEL
INSTABILITY. 20

&&

.PREVIOUS DISCUSSION... /ISSUED 233 PM PDT FRI MAY 22 2015/

SYNOPSIS...

A COUPLE MORE DAYS OF SHOWERS AND THUNDERSTORMS ALONG WITH BELOW
NORMAL TEMPERATURES ARE EXPECTED AS AN AREA OF LOW PRESSURE REMAINS
ANCHORED OVER THE WEST. SHOWER AND THUNDERSTORM COVERAGE WILL
DECREASE THROUGH THE MEMORIAL DAY WEEKEND WITH TEMPERATURES
GRADUALLY WARMING TO NEAR NORMAL. LOWER END CHANCES FOR SHOWERS WILL
LINGER INTO NEXT WEEK, BUT THE TREND IS TOWARDS DRIER AND WARMER
CONDITIONS.

SHORT TERM...

TODAY HAS BEEN ANOTHER ACTIVE DAY FOR CONVECTION WITH AMPLE
INSTABILITY AND MOISTURE FOR SHOWERS AND THUNDERSTORMS. HOWEVER,
MORNING CLOUD CONTAMINATION AND THE FACT THAT EVERYWHERE IS
CONVECTING AT ONCE IS LIMITING ANY SINGLE CELLS FROM BECOMING VERY
STRONG DESPITE CAPE VALUES AROUND 1000 J/KG. THE SHOWERS THAT HAVE
OCCURRED HAVE BEEN MODERATE TO HEAVY WITH PEA SIZE HAIL MIXED IN.
EXPECT CHAOTIC SHOWER FORMATION FOR THE REST OF THE AFTERNOON WITH
SHOWERS DIMINISHING ONCE AGAIN THIS EVENING. SOME MESOSCALE
MODELS ARE SHOWER LINGERING CLOUD COVER OVERNIGHT WITH ANOTHER
ROUND OF SHOWERS POSSIBLE DURING THE EARLY MORNING HOURS MAINLY
EAST OF ALTERNATE 95.

OTHERWISE, NO MAJOR CHANGES WERE MADE TO THE PREVIOUS FORECAST
WHICH CONTINUES TO VERIFY WELL. OVERALL, CHANCES OF SHOWERS WILL
BE LOWER THE NEXT COUPLE OF DAYS AS LOW PRESSURE EXITS INTO THE
FOUR-CORNERS REGION. HOWEVER, THE LONG WAVE TROUGH REMAINS OVER
NEVADA WITH ADDITIONAL SMALLER DISTURBANCE MOVING THROUGH THE
PATTERN. THIS WILL KEEP CHANCE OF SHOWERS/THUNDERSTORMS IN THE
FORECAST THROUGH THIS WEEKEND. THE FOCUS OF SHOWERS AND CONVECTION
BECOMES MORE CONCENTRATED OVER THE SIERRA AND CENTRAL NEVADA
SATURDAY AND SUNDAY AFTERNOONS, BUT ISOLATED CHANCES REMAIN FOR
THE SIERRA FRONT AS WELL.

LONG TERM...MONDAY THROUGH FRIDAY...

VERY FEW CHANGES MADE TO THE LONG TERM FORECAST FOR NEXT WEEK.
MODELS ARE IN BETTER AGREEMENT WITH KEEPING IT UNSETTLED FOR EARLY
IN THE WEEK THEN TRANSITIONING TO A DRIER, WARMER PATTERN FOR THE
END OF THE WEEK.

A LOW PRESSURE SYSTEM DROPS DOWN INTO THE PACIFIC NORTHWEST ON
MONDAY AND TUESDAY WITH A BAND OF SHOWERS PROGRESSING SOUTHWARD
ACROSS THE SIERRA AND WESTERN NEVADA. EXPECT LIGHT SHOWERS AND
THUNDERSTORMS TO PERSIST EACH AFTERNOON THROUGH AT LEAST WEDNESDAY
ALONG WITH AVERAGE TEMPERATURES IN THE 60S AND 70S.

BY WEDNESDAY AND THURSDAY, RIDGING BUILDS IN ACROSS THE WEST COAST
BRINGING A WARMING AND DRYING TREND FOR THE END OF THE WEEK.
CONVECTION MAY STILL DEVELOP EACH AFTERNOON ALONG THE SIERRA CREST
WITH HIGHS NEARING 80 DEGREES IN WESTERN NEVADA TOWARD THE END OF
THE WEEK. ELW

AVIATION...

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO DEVELOP THROUGH
THIS EVENING. AREAS OF MVFR CONDS TO CONTINUE IN THE SIERRA INTO THE
AFTERNOON AND EVENING WITH CIGS NEAR 4-5000 FEET FOR WRN NV AT LEAST
THRU 06Z. WINDS WILL REMAIN LIGHT OUTSIDE OF ANY OUTFLOWS FROM
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. MTN OBSCURATIONS LIKELY
FOR SATURDAY MORNING ALONG WITH THE POSSIBILITY OF FOG FOR KTVL AND
KTRK. MORE SHOWERS POSSIBLE ON SATURDAY, BUT EXPECTED TO HAVE LESS
COVERAGE AND IMPACTS COMPARED TO TODAY AND THE LAST 2 DAYS.
WALLMANN/ELW

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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


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