Special Weather Statement, NWS Reno, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
913 AM PDT SAT JUL 27 2013

.UPDATE...

THE ONLY CHANGE MADE MID MORNING WAS TO ADD A FLASH FLOOD WATCH
AND THE MENTION OF HEAVY RAIN FOR MONO, MINERAL, AND SOUTHERN LYON
COUNTIES FOR THIS AFTERNOON INTO THIS EVENING. JET DYNAMICS WILL
BE INCREASING ALLOWING FOR WELL VENTILATED AND SELF-SUSTAINING
STORMS THIS AFTERNOON FOR AREAS SOUTH OF HIGHWAY 50. COMBINED WITH
ALREADY HIGH PRECIPITABLE WATER VALUES AND WEAKER STORM MOTIONS
LESS THAN 15-20 MPH, THE THREAT FOR SHOWERS OR STORMS THAT WILL
BE ABLE TO PRODUCE HEAVY RAIN IS INCREASING. THERE ARE SOME LOW
LEVEL CLOUDS COVERING SOUTHERN MONO COUNTY THAT MAY INHIBIT
CONVECTION FOR AREAS SOUTH OF MONO LAKE. HOWEVER, IF THESE CLOUDS
BURN OFF LATE IN THE MORNING TO EARLY AFTERNOON, THE FLASH FLOOD
THREAT WILL EXTEND SOUTHWARD IN MONO COUNTY.

&&

.SYNOPSIS...
MOIST AND UNSTABLE AIR MASS WILL KEEP THE THREAT OF SHOWERS AND
THUNDERSTORMS MAINLY SOUTH OF HIGHWAY 50 THROUGH THIS WEEKEND WHILE
A GRADUAL DRYING TREND WILL REDUCE THE THUNDERSTORM POTENTIAL
ELSEWHERE. DRY AND LOCALLY BREEZY CONDITIONS ARE EXPECTED NEXT WEEK
WITH TEMPERATURES SLIGHTLY BELOW NORMAL.

&&

.SHORT TERM...

THE CONVECTION FROM LAST NIGHT IN WEST CENTRAL NV HAS FINALLY
WOUND DOWN, ALTHOUGH SOME SHOWERS IN NORTHERN INYO COUNTY ARE
LIKELY TO MOVE NORTH INTO SOUTHERN PORTIONS OF MONO AND MINERAL
COUNTIES THIS MORNING. BY THIS AFTERNOON, THE HIGHEST AMOUNTS OF
MOISTURE AND INSTABILITY ARE EXPECTED TO REMAIN IN AREAS SOUTH OF
HIGHWAY 50. A FEW AREAS IN SOUTHERN LYON AND MINERAL COUNTIES
WHICH RECEIVED HEAVY RAINFALL AND REPORTS OF FLOODING YESTERDAY
WILL NEED TO BE WATCHED FOR A POSSIBLE REPEAT TODAY, BUT THE
CONFIDENCE LEVEL FOR THESE SAME AREAS RECEIVING MORE HEAVY RAIN IS
NOT HIGH ENOUGH TO ISSUE ANY FLOOD WATCHES. BOTH THE GFS AND NAM
HAVE FOCUSED MORE PRECIP BACK INTO MONO COUNTY UNDER A SMALL
DEFORMATION ZONE ASSOCIATED WITH THE UPPER LOW OFF THE SOUTHERN CA
COAST. HOWEVER, MOST OF THIS COUNTY RECEIVED LITTLE MEASURABLE
RAINFALL YESTERDAY.

FARTHER NORTH, AN INCREASING WEST FLOW BRINGING DRIER AIR WILL
LIMIT THE THUNDERSTORM THREAT TODAY ESPECIALLY AROUND THE TAHOE
BASIN AND NORTHWARD INTO PLUMAS COUNTY. OTHERWISE, SOME RESIDUAL
MOISTURE AND INSTABILITY COULD TRIGGER A FEW BRIEF CELLS IN THE
REMAINDER OF EASTERN CA-WESTERN NV NORTH OF HIGHWAY 50 FROM MID
AFTERNOON AND INTO THIS EVENING. INTENSITY OF MOST STORMS WILL BE
SIMILAR TO YESTERDAY, GENERALLY BELOW SEVERE LEVELS BUT INTERACTIONS
WITH OUTFLOW BOUNDARIES AND/OR THE LATE DAY ZEPHYR COULD PULSE
SOME STORMS BRIEFLY NEAR LOW END SEVERE CRITERIA. THE UPPER LEVEL
JET STREAK WHICH HELPED SUSTAIN STORMS THE PAST COUPLE OF NIGHTS
IS EXPECTED TO DEPART WESTERN NV BY TONIGHT, SO THE POST-SUNSET
DIMINISHING TREND OF THE CONVECTION SHOULD TAKE LESS TIME COMPARED
TO YESTERDAY. THE ONLY EXCEPTION WOULD BE NEAR THE SMALL
DEFORMATION ZONE IN MONO AND MINERAL COUNTIES WHERE ISOLATED
SHOWERS COULD PERSIST OVERNIGHT.

ON SUNDAY, THE DRIER AIR MASS IS EXPECTED TO SPREAD FARTHER SOUTH
AS THE TROUGH IN THE NORTHWEST US PUSHES INTO NORTHERN CA, WITH
CONVECTION UNLIKELY NORTH OF HIGHWAY 50. HOWEVER, WINDS WILL
INCREASE IN THESE AREAS WITH LOCAL GUSTS UP TO 35 MPH POSSIBLE
FROM RENO NORTHWARD INTO NERN CA-NWRN NV.

FOR MONDAY, WHILE DRY WEATHER SHOULD PREVAIL WITH LATE DAY BREEZES
REACHING SPEEDS SIMILAR TO SUNDAY, THE LATEST MODEL GUIDANCE HANGS
ON TO SOME INSTABILITY OVER FAR SOUTHERN MONO COUNTY AND EASTERN
MINERAL COUNTY. THIS AREA WILL BE WATCHED DURING THE NEXT DAY OR
TWO TO SEE IF THE GUIDANCE RETAINS THIS INSTABILITY, BUT WILL NOT
ADD MENTION OF THUNDER AT THIS TIME.

DAYTIME TEMPS NEAR OR SLIGHTLY ABOVE SEASONAL NORMAL TODAY WILL
GRADUALLY COOL DOWN THRU EARLY NEXT WEEK AS 500 MB HEIGHTS AND
700 MB TEMPS ALSO DECREASE. BY MONDAY, MAX TEMPS WILL GENERALLY
RANGE FROM 90-95 IN WESTERN NV TO AROUND 80 DEGREES IN THE TAHOE
BASIN AND SIERRA VALLEYS. MJD

.LONG TERM...

MAKE FEW CHANGES AS THE MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH
THE LARGE SCALE PATTERN. GENERAL WEST FLOW ALOFT TO CONTINUE WITH
THE MAIN TROUGH CENTERED NEAR THE COAST WITH THE DEEPEST PART OVER
WASHINGTON. MODELS NOW IN BETTER AGREEMENT WITH THE STRONGER SHORT
WAVE TO AFFECT THE SIERRA AND WESTERN NEVADA WEDNESDAY. WITH A GOOD
THERMAL GRADIENT AND A DECENT SFC PRESSURE/HGT GRADIENT ALOFT, IT
COULD BE A DECENT MID-SUMMER SW WIND EVENT WITH GUSTS 30-40 MPH OVER
MUCH OF THE REGION. BUMPED UP WINDS A BIT FOR WED WITH BETTER MODEL
AGREEMENT. OUTSIDE OF WEDNESDAY, EXPECT TYPICAL AFTERNOON WEST WINDS
WITH PEAK GUSTS 20-30 MPH. TEMPERATURES LOOK TO REMAIN NEAR AVERAGE
DURING THE DAY WITH SEASONABLE TO COOL OVERNIGHT LOWS DUE TO THE
VERY DRY AIR EXPECTED. WALLMANN

&&

.AVIATION...

STILL EXPECT THUNDERSTORMS THIS AFTERNOON FOCUSED SOUTH OF HWY 50.
BEST CHC AFFECTING ANY TERMINALS WOULD BE AT KMMH FROM 21-01Z.
FURTHER NORTH, A SLIGHT CHC REMAINS FOR KRNO/KCXP BEFORE 23Z WITH A
MINIMAL THREAT FOR THE TAHOE TERMINALS KTRK/KTVL. THREATS REMAIN
BRIEF HEAVY RAIN, SMALL HAIL AND SOME SFC WND GUSTS TO 40 KTS.
EXPECT ALL STORMS TO DIE OFF AROUND 04Z WITH AN EVEN SMALLER THREAT
FOR STORMS SUNDAY. WALLMANN

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH FROM 2 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING NVZ001.

CA...FLASH FLOOD WATCH FROM 2 PM THIS AFTERNOON TO 9 PM PDT THIS
     EVENING CAZ073.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
547 AM PDT SAT JUL 27 2013

CAZ070>073-NVZ001>005-280100-
SURPRISE VALLEY CALIFORNIA-LASSEN-EASTERN PLUMAS-
EASTERN SIERRA COUNTIES-GREATER LAKE TAHOE AREA-MONO-
MINERAL AND SOUTHERN LYON COUNTIES-GREATER RENO-CARSON CITY-
MINDEN AREA-WESTERN NEVADA BASIN AND RANGE INCLUDING PYRAMID LAKE-
NORTHERN WASHOE COUNTY-
547 AM PDT SAT JUL 27 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE EASTERN SIERRA...
NORTHEAST CALIFORNIA AND WESTERN NEVADA.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE EASTERN SIERRA AND WESTERN NEVADA THIS
AFTERNOON AND SHOULD CONTINUE INTO THE EVENING. LOCALLY HEAVY
RAIN...HAIL...GUSTY WINDS AND DEADLY LIGHTNING CAN BE EXPECTED
WITH THE STORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED SHOWERS AND THUNDERSTORMS ARE AGAIN POSSIBLE ON SUNDAY
...MAINLY SOUTH OF INTERSTATE 80. HIGH PRESSURE WILL THEN START TO
BUILD INTO THE REGION ON MONDAY WITH DRY CONDITIONS AND NEAR
NORMAL TEMPERATURES THROUGH NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...
SKYWARN SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON. SPOTTERS
ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER ACCORDING TO STANDARD
OPERATING PROCEDURES.

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

O'HARA

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RENO NV
117 PM PDT SAT JUL 27 2013

CAZ073-NVZ001-272100-
MINERAL AND SOUTHERN LYON COUNTIES-MONO-
117 PM PDT SAT JUL 27 2013

...STRONG STORMS DEVELOPING ACROSS MONO COUNTY...

AT 108 PM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A CLUSTER OF DEVELOPING STRONG AND NEARLY STATIONARY THUNDERSTORMS
SOUTH OF BRIDGEPORT NEAR BODIE. STORMS ARE ALSO DEVELOPING NEAR
CRESTVIEW.

OCCASIONAL LIGHTNING...HEAVY RAIN WITH AMOUNTS NEAR ONE INCH PER
HOUR...PENNY SIZE HAIL...AND GUSTY WINDS TO 45 MPH...WILL OCCUR WITH
THESE STORMS.

* LOCATIONS AFFECTED INCLUDE......BODIE...CONWAY SUMMIT...CRESTVIEW
AND JUNE LAKE.

HEAVY RAINFALL IS OCCURRING WITH THIS STORM. EXPECT PONDING OF WATER
ON ROADWAYS. IN AREAS OF STEEP TERRAIN...MINOR ROCK SLIDES ARE
POSSIBLE. DRIVERS SHOULD SLOW DOWN AND TURN ON THEIR HEADLIGHTS IF
ENCOUNTERING HEAVY RAINS.

&&

LAT...LON 3822 11943 3840 11864 3777 11838 3763 11905
      3772 11913 3771 11925 3777 11927 3780 11922
      3790 11923 3795 11933 3805 11932 3809 11938
TIME...MOT...LOC 2012Z 169DEG 2KT 3820 11913

TF