Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 020905
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
205 AM PDT TUE JUN 2 2015

.SYNOPSIS...

EXPECT DRY CONDITIONS TODAY AND A SLIGHT CHANCE FOR THUNDERSTORMS
WEDNESDAY NORTH OF A SUSANVILLE TO GERLACH LINE. THUNDERSTORM
CHANCES EXPAND OVER THE SIERRA AND WESTERN NEVADA BY THURSDAY AS
ANOTHER LOW PRESSURE DROPS INTO CALIFORNIA. TEMPERATURES WILL
REMAIN NEAR AVERAGE THROUGH THE WEEK.

&&

.SHORT TERM...
A DISTURBANCE MOVING EASTWARD THROUGH OREGON TODAY MAY CREATE
SPRINKLES THIS AFTERNOON IN FAR NORTHEAST CA/NORTHWEST NV, MAINLY
NEAR THE OREGON BORDER. ELSEWHERE (SOUTH OF SUSANVILLE-GERLACH),
EXPECT DRY CONDITIONS AND PARTLY CLOUDY SKIES TODAY AS WE ARE
BETWEEN SYSTEMS. FOR WEDNESDAY, AS A LOW-PRESSURE TROUGH DEVELOPS
SOUTHWARD ALONG THE CALIFORNIA COAST THERE IS A SLIGHT CHANCE FOR
SHOWERS AND THUNDERSTORMS OVER FAR NORTHEAST CA/NORTHWEST NV.

FOR THURSDAY, MID-RANGE MODELS AND ENSEMBLES HAVE COME INTO GOOD
AGREEMENT SHOWING A CLOSED LOW CENTERED OVER THE CENTRAL CA COAST.
THIS PROVIDES A FEW GOOD INGREDIENTS FOR THUNDERSTORM DEVELOPMENT
OVER THE SIERRA AND WESTERN NV INCLUDING DIVERGENCE ALOFT AND
ENOUGH SFC-6 KM SHEAR TO AID UPDRAFT DEVELOPMENT. THERE ACTUALLY
MAY BE TOO MUCH SHEAR (30-40 KTS) COMPARED TO CAPE TO SUSTAIN
STRONG UPDRAFTS OVER MINERAL, CHURCHILL, PERSHING COUNTIES. LACK
OF MOISTURE IS ALSO A LIMITING FACTOR SOUTH OF I-80, BUT FAIRLY
MOIST PRECIPITABLE WATER VALUES OF 0.50-0.60 INCH ARE EXPECTED
NORTH OF I-80. THIS SET UP COULD LEAD TO MOSTLY SHOWERS/SHALLOW
CONVECTION IN NORTHEAST CA/NORTHWEST NV WITH THE BEST CHANCE FOR
THUNDERSTORMS ALONG THE I-80 CORRIDOR. AS SUCH, WE NUDGED UP
CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON/EVENING
BUT MAINTAINED SCATTERED COVERAGE RATHER THAN NUMEROUS. AS THE
UPPER TROUGH CONTINUES TO MOVE EAST, ISOLATED SHOWERS MAY PERSIST
THURSDAY NIGHT INTO FRIDAY MORNING. JCM

.LONG TERM...FRIDAY THROUGH MONDAY...

MEDIUM RANGE MODELS ARE LINED UP A LITTLE BETTER FOR THE END OF THE
WEEK INTO THE WEEKEND BUT SUBTLE DIFFERENCES REMAIN WITH THE
LOCATION OF THE UPPER LOW EARLY IN THE PERIOD THAT GROW INTO NOT AS
SUBTLE DIFFERENCES BY THE END OF THE PERIOD.

OVERALL...FEW CHANGES WERE MADE TO DAYS 4 THROUGH 6...WITH A FEW
MORE CHANGES TO DAY 7. THE DETERMINISTIC GFS IS MORE IN LINE WITH
ITS ENSEMBLE MEMBERS AND THE ECMWF AND IS NO LONGER PICKING UP THE
REMNANTS OF HURRICANE ANDRES AND DRAGGING ITS MOISTURE INTO THE
REGION. STILL...THERE SHOULD BE ENOUGH MOISTURE AROUND FRIDAY AND
SATURDAY FOR DECENT COVERAGE OF CONVECTION. STILL THINK THAT MOST OF
THE CONVECTION WILL BE SHOWERS WITH A FEW THUNDERSTORMS THROWN
IN...BUT THIS IS LARGELY DEPENDENT ON HOW MUCH CLOUD COVER THERE
WILL BE AND IF CONVECTION STARTS EARLY ENOUGH EACH DAY TO LIMIT
SURFACE BASED INSTABILITY. THE UPPER LOW IS IN PLACE THROUGH SUNDAY
BUT IT IS DIFFICULT THIS FAR OUT TO DETERMINE THE LOCATION OF THE
BEST PCPN CHANCES...SO WE WILL KEEP JUST A BROAD BRUSHED CHANCE POP
WORDING IN THE DAYTIME AND SLIGHT CHANCE AT NIGHT. HIGH TEMPS EACH
DAY SHOULD BE NEAR AVERAGE WITH OVERNIGHT LOWS ABOVE AVERAGE.

MONDAY IS A BIT MORE PROBLEMATIC. WHILE BOTH THE GFS AND ECMWF AND
MOST ENSEMBLE MEMBERS OF THE GEFS KEEP THE LOW NEAR THE FORECAST
AREA...THERE ARE DIFFERENCES IN HOW STRONG IT REMAINS AND HOW FAST
IT LIFTS OUT. SOME OF THE ENSEMBLE MEMBERS ARE FASTER TO MOVE IT OUT
BUT THE DETERMINISTIC MODELS ARE HOLDING ON TO THE FEATURE. WE HAVE
STARTED THE PROCESS OF RAISING POPS SLOWLY THIS CYCLE. THE GFS IS
ALSO SHOWING A TENDENCY TO PICK UP MOISTURE FROM TS BLANCA BY LATE
MONDAY. THIS WOULD BE IN LINE WITH THE NHC FORECAST AND MAINLY
AFFECT POINTS EAST OF OUR CWA. STILL...IT COULD AFFECT OUR AREA IF
THE UPPER LOW SLOWS AND HANGS AROUND INTO TUESDAY.

OVERALL CONFIDENCE IS INCREASING IN PCPN CHANCES FOR FRIDAY THROUGH
SUNDAY AND SUBSEQUENT FORECAST SHIFTS WILL LIKELY NEED TO RAISE POPS
FURTHER. THERE IS A BIT LESS CONFIDENCE IN MONDAY`S FORECAST...BUT
IT APPEARS THE TREND THERE WILL BE TOWARD INCREASING POPS AS WELL. 20

&&

.AVIATION...

VFR AGAIN TODAY WITH LESS WIND AT THE SURFACE AND ALOFT THAN THE
PREVIOUS TWO DAYS. BEST ENERGY FOR CONVECTION IS NORTH OF THE OREGON
BORDER THROUGH EARLY WEDNESDAY.

BY LATE WEDNESDAY ANOTHER AREA OF LOW PRESSURE STARTS TO DROP SOUTH
TOWARD THE REGION THEN MOVES OVER CA BY THURSDAY. THIS WILL LEAD TO
INCREASED SKY COVER AND PCPN CHANCES AS WE GO INTO THE LATTER HALF
OF THE WEEK AND NEXT WEEKEND. FLYING CONDITIONS ARE LIKELY TO
DETERIORATE AS CIGS LOWER A BIT AND TURBULENCE INCREASES AROUND
CONVECTION FROM THURSDAY INTO THE WEEKEND. 20

&&

.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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