Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 032020
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
120 PM PDT SUN MAY 3 2015

.SYNOPSIS...
WARM TEMPERATURES AND CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
CONTINUE THROUGH MONDAY. A LOW PRESSURE SYSTEM DROPPING OUT OF
THE GULF OF ALASKA WILL BRING AN UNSETTLED WEATHER PATTERN BY
MIDWEEK WITH MORE WIDESPREAD SHOWER ACTIVITY. DAYTIME TEMPERATURES
AS MUCH AS 20 DEGREES COOLER FROM MONDAY TO THURSDAY.

&&

.SHORT TERM...
ONLY MINOR CHANGES WERE MADE TO THE SHORT TERM FORECAST TODAY. A
BROAD WEAK TROUGH WITH LIGHT FLOW ALOFT REMAINS IN PLACE. INSTABILITY
DRIVEN BY DAYTIME HEATING WILL ONCE AGAIN PRODUCE MODERATE CONVECTION
OVER AREAS SOUTH OF HIGHWAY 50 LATE THIS AFTERNOON AND EVENING AND
POSSIBLY IN THE LASSEN CONVERGENCE ZONE ACROSS LASSEN COUNTY AND
INTO FAR NORTHERN WASHOE COUNTY. INSTABILITY IS WEAKER HERE...SO
THUNDERSTORMS WILL BE MORE ISOLATED IN NATURE.

ONE MORE DAY OF THIS PATTERN IS IN STORE FOR MONDAY...BUT THE
TROUGH IS STARTING TO PUSH EAST. A ZEPHYR-TYPE LATE AFTERNOON WIND
SHOULD DEVELOP MONDAY AND DRIVE ANY DEVELOPMENT IN THE TAHOE BASIN
TO THE EAST BY EARLY EVENING. TEMPS MAY BE A DEGREE OR TWO COOLER
THAN TODAY. THUNDERSTORMS BOTH THIS EVENING AND MONDAY ARE LIKELY
TO PRODUCE BRIEF GUSTY WINDS TO 40-45 MPH AND SMALL HAIL. A FEW
MAY PRODUCE LIGHT TO MODERATE RAIN AT THE SURFACE...BUT THESE ARE
MORE LIKELY IN THE HIGHER ELEVATIONS.

THE BIGGER CHANGES BEGIN TUESDAY AS AN UPPER LEVEL AREA OF LOW
PRESSURE STARTS TO DROP SOUTH INTO THE REGION. THIS WILL PRODUCE
STRONGER SOUTHWEST FLOW ALOFT WHICH SHOULD LIMIT CONVECTIVE
DEVELOPMENT TO AREAS WELL SOUTH OF HIGHWAY 50. A FEW SHOWERS MAY
BE POSSIBLE OVER THE FAR NORTH...BUT NO DEEP CONVECTION. THIS LOW
IS LIKELY TO INDUCE STRONGER SURFACE WINDS AS WELL BY LATE
TUESDAY.

THE LOW MOVES CLOSER ON WEDNESDAY WITH COOLING ALOFT LEADING TO
MORE WIDESPREAD SHOWERS AND DAYTIME HIGHS ACTUALLY FALLING BELOW
AVERAGE. BROADER COVERAGE OF SHALLOW CONVECTION WEDNESDAY MAY
DETER SURFACE ENOUGH TO LIMIT THE POSSIBILITY OF THUNDERSTORMS...
BUT WILL LEAVE SOME MENTION IN THE FORECAST AS INSTABILITY MAY BE
SUFFICIENT TO PRODUCE A FEW ISOLATED STORMS DURING THE LATE
AFTERNOON. 20

.LONG TERM...THURSDAY THROUGH SUNDAY...

FORECAST CONFIDENCE FOR COOLER AND WETTER CONDITIONS HAS
INCREASED TO MEDIUM AS MODELS CONTINUE TO SHOW A SLOW MOVING
TROUGH OVER THE AREA THURSDAY-FRIDAY. THE MAIN CHANGE TO THE LONG
TERM FORECAST WAS FOR COOLER AFTERNOON TEMPERATURES, WITH HIGHS
THURSDAY NOW FORECAST TO BE IN THE 50S FOR MOST COMMUNITIES. THERE
IS POTENTIAL FOR HIGHS TO BE EVEN COOLER (IN THE 40S), IF CLOUDY
AND RAIN-COOLED CONDITIONS PERSIST ALL DAY.

WITH THESE COOL TEMPERATURES AT THE SURFACE, DEEP CONVECTION AND
THUNDERSTORMS BECOME LESS LIKELY, WHILE THE AREAL COVERAGE OF SHALLOW
CONVECTION AND SHOWERS IS LIKELY TO INCREASE.  AS SUCH, THE MAIN
WEATHER CONCERNS ARE (1) SNOW AND/OR ICE PELLET ACCUMULATIONS ON
ROADWAYS, AND (2) ANYONE WORKING OR RECREATING OUTDOORS IN THE
MOUNTAINS SHOULD PREPARE FOR WINTER-LIKE CONDITIONS.

FORECAST MODEL SOLUTIONS CONTINUE TO SHOW POTENTIAL FOR A
WRAP-AROUND PRECIPITATION BAND TO SET UP THURSDAY AND FRIDAY WHICH
COULD LEAD TO HIGHER PRECIPITATION AMOUNTS.  BUT DIFFERENCES MAKE IT
DIFFICULT TO PINPOINT THE BEST CHANCES FOR PRECIPITATION AT THIS
TIME. BY SATURDAY/SUNDAY, MODEL SOLUTIONS ARE SHOWING A SLIGHT
WARMUP WITH POTENTIAL FOR ISOLATED SHOWERS AS ZONAL FLOW ATTEMPTS TO
SET UP ACROSS THE WEST. JCM

&&

.AVIATION...
ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH 04Z THIS
AFTERNOON/EVENING WITH THE BEST CHANCES SOUTH OF HIGHWAY 50. THESE
STORMS MAY PRODUCE MODERATE RAIN, SMALL HAIL AND GUSTY OUTFLOW WINDS
TO 35 KTS. KNFL AND KLOL HAVE A HIGHER CHANCE TO BE AFFECTED BY A
THUNDERSTORM, ESPECIALLY AFTER CONVECTION MOVES EASTWARD AWAY FROM
THE SIERRA THIS AFTERNOON. ISOLATED SHOWERS MAY PERSIST OVERNIGHT
MAINLY SOUTH OF HIGHWAY 50. JCM

&&

.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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