Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 292209
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
309 PM PDT MON JUN 29 2015

.SYNOPSIS...

HOT TEMPERATURES WILL RETURN THIS WEEK AS HIGH PRESSURE STRENGTHENS
OVER THE GREAT BASIN. MOISTURE WILL REMAIN TRAPPED UNDERNEATH THE
RIDGE AND ALLOW FOR A CHANCE OF THUNDERSTORMS EACH AFTERNOON
THROUGH THE 4TH OF JULY WEEKEND.

&&

.SHORT TERM...

AMPLIFIED RIDGE OVER THE GREAT BASIN TODAY IS ALLOWING ABUNDANT
MOISTURE TO CONTINUE TO MOVE IN FROM THE SOUTH. STORM DEVELOPMENT
HAS ALREADY INITIATED TODAY WITH MULTIPLE CELLS IN LYON AND
DOUGLAS COUNTIES BY 1PM. THE BEST INSTABILITY TODAY IS ALONG AND
JUST EAST OF THE SIERRA CREST. GOOD CLEARING THIS MORNING HAS
ALLOWED FOR BETTER HEATING THAN YESTERDAY, COMBINED WITH
SIGNIFICANT PWAT OF NEAR AN INCH, EVIDENT IN THE 12Z SOUNDING.
STORMS AREN`T EXPECTED TO BE OVERLY STRONG TODAY WITH LIMITED
INSTABILITY AND FORCING, BUT STORMS TRAINING OVER THE SAME AREA
COULD CREATE VERY ISOLATED FLOODING CONCERNS ESPECIALLY OVER BURN
SCARES.

MODELS INDICATE SOME MID-LEVEL DRYING MONDAY NIGHT AS THE AXIS OF
THE HIGH PRESSURE FLATTENS, THIS SHOULD AGAIN ALLOW FOR GOOD
DAYTIME HEATING ON TUESDAY. THE 12Z RUN OF THE GFS ALSO HAS AN
UPPER LEVEL WAVE WELL TIMED FOR TUESDAY`S PEAK HEATING THAT WOULD
ADD SOME FORCING. INSTABILITY LOOKS AS GOOD IF NOT BETTER
TOMORROW BUT DRY AIR ALOFT MAY LIMIT THUNDERSTORM ACTIVITY
DEPENDING ON THE TIMING AND PLACEMENT OF THE DRIER AIR.
THUNDERSTORMS WILL ALSO BE POSSIBLE ON WEDNESDAY BUT INSTABILITY
DOESN`T LOOK AS GOOD WITH DEVELOPMENT EXPECTED MAINLY SOUTH OF
I-80. FOR ADDITIONAL DETAILS ON THUNDERSTORMS SEE THE FIRE WEATHER
DISCUSSION BELOW.

AFTER A BRIEF COOL DOWN ON SUNDAY, AFTERNOON TEMPERATURES ARE
AGAIN EXPECTED TO REMAIN NEAR OR ABOVE 100 WITH SOME AREAS IN WEST
CENTRAL NEVADA EXCEEDING 105. IN ADDITION TO VERY HOT DAYTIME HIGH
TEMPERATURES, OVERNIGHT LOWS WILL REMAIN NEAR 70 DEGREES ADDING TO
POTENTIAL HEAT IMPACTS. A HEAT ADVISORY HAS BEEN ISSUED FOR WEST
CENTRAL NEVADA INCLUDING THE AREAS AROUND LOVELOCK AND FALLON.
TEMPERATURES WILL REMAIN VERY HOT THROUGHOUT THE REGION THIS
WEEK,THOUGH AREAS CLOSER TO THE SIERRA HAVE A BETTER CHANCE FOR
LATE AFTERNOON COOLING DUE CLOUD COVERAGE FROM THUNDERSTORMS.
TOLBY

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

TWO SIGNIFICANT WEATHER CONCERNS THIS WEEK: (1) SEVERAL DAYS IN A
ROW OF HOT TEMPERATURES; AND (2) THE POTENTIAL FOR THUNDERSTORMS
IMPACTS. A HIGH PRESSURE RIDGE OVER NEVADA THROUGH THURSDAY IS
EXPECTED TO SLOWLY SHIFT EAST TOWARDS THE 4-CORNERS REGION THIS
WEEKEND.

A HEAT ADVISORY IS IN EFFECT THROUGH THURSDAY FOR THE WESTERN BASIN
AND RANGE ZONE INCLUDING FERNLEY, PYRAMID LAKE, FALLON AND LOVELOCK.
AFTER RECORD OR NEAR RECORD TEMPERATURES THURSDAY, A SLOW COOLING
TREND MAY BEGIN FRIDAY AS THE RIDGE SHIFTS EAST.  HOWEVER,
TEMPERATURES SHOULD REMAIN WELL ABOVE NORMAL GOING INTO THE WEEKEND.
WHEN HEAT EVENTS LAST SEVERAL DAYS IN A ROW LIKE THIS ONE, VISITS TO
EMERGENCY CARE CENTERS DUE TO HEAT ILLNESS TEND TO INCREASE EACH DAY
AS THE EVENT GOES ON.  THUS, PLEASE TAKE EXTRA CARE TO STAY
HYDRATED AND AVOID DIRECT SUNLIGHT WHEN POSSIBLE.

THE OTHER NOTABLE WEATHER FEATURE THIS WEEK IS NEAR RECORD MOISTURE
ALOFT.  THE AIR MASS NEAR THE SURFACE WILL REMAIN VERY DRY UNLESS
THERE IS A SHOWER OR THUNDERSTORM, BUT ALOFT PRECIPITABLE WATER (PW)
VALUES WILL BE NEAR RECORD LEVELS.  EXPECT PW VALUES AROUND 0.75 TO
0.90 INCH THURSDAY TO INCREASE GOING INTO THE WEEKEND AS MOIST AIR
FROM OVER THE PACIFIC MOVES ACROSS THE SIERRA INTO WESTERN NV. THIS
ABUNDANT MOISTURE, COUPLED WITH THE INTENSE SURFACE HEATING, RAISES
THE POTENTIAL FOR SEVERE THUNDERSTORMS AND/OR FLASH FLOODING EACH
AFTERNOON/EVENING OF THE LONG TERM FORECAST PERIOD.  WHILE THE
POTENTIAL IS HIGH, THE AMOUNT OF ACTIVITY EACH DAY MAY BE LIMITED BY
CLOUD COVER (TOO MUCH LIMITS INSTABILITY) AND THE STRENGTH AND
TIMING OF ANY UPPER IMPULSES (WHICH TEND TO BE TOO SMALL SCALE FOR
US TO FORECAST MORE THAN A DAY OR SO AHEAD OF TIME). THE BOTTOM
LINE: STAY TUNED TO THUNDERSTORM FORECAST UPDATES THIS WEEK AND
WEEKEND, ESPECIALLY IF PLANNING ANY OUTDOOR ACTIVITIES.  JCM

&&

.AVIATION...LIGHT WINDS THIS AFTERNOON/EVENING EXCEPT FOR SOME SW
WIND GUSTS TO 20 KTS NEAR/NORTH OF I-80.  THERE IS A 15-30 PCT
CHANCE OF THUNDERSTORM IMPACTS TODAY THOUGH 03Z WITH POTENTIAL FOR
GUSTY OUTFLOW WINDS CAUSING SUDDEN CHANGES IN WIND SPEED AND
DIRECTION.  A SIMILAR PATTERN IS EXPECTED TUESDAY. JCM

&&

.FIRE WEATHER...

IT WILL BE ANOTHER WEEK WITH NEAR RECORD HIGH TEMPERATURES AND
CHANCES FOR THUNDERSTORMS. THE BEST CHANCES FOR STORMS TODAY WILL BE
FOR MUCH OF THE SIERRA AND NORTHWEST NEVADA, SOUTH AND EAST OF A
SUSANVILLE-GERLACH LINE. STORMS TOMORROW MAY BE FOCUSED MAINLY SOUTH
OF INTERSTATE 80 TUESDAY AND WEDNESDAY AS SOME DRIER AIR WORKS INTO
THE REGION. STORM COVERAGE IS EXPECTED TO EXPAND NORTHWARD TO THE
OREGON BORDER BY THURSDAY AND FRIDAY. STORMS WILL PRIMARILY BE WET,
BUT THE ONE AREA OF CONCERN WILL BE THE LASSEN AND PLUMAS NATIONAL
FORESTS ON THURSDAY. STORMS MAY BE MORE OF A WET/DRY HYBRID NATURE
AS MOISTURE BEGINS TO SPREAD INTO THE REGION. GUSTY AND ERRATIC
WINDS ARE ALWAYS A CONCERN WITH THUNDERSTORMS, BUT THE ENVIRONMENT
THIS WEEK IS NOT AS CONDUCIVE TO OUTFLOWS OF THE MAGNITUDE SEEN THIS
PAST SATURDAY. ESTIMATE THUNDERSTORM WIND GUSTS OF 40 TO 50 MPH,
OTHERWISE WINDS WILL BE LIGHT THROUGH THE WEEK.

AS MOISTURE DRAMATICALLY INCREASES LATE IN THE WEEK AND INTO THE
WEEKEND, HEAVIER RAINS ARE POSSIBLE ALONG WITH SLOW STORM MOTIONS,
BRINGING THE POTENTIAL FOR FLASH FLOODING IF THE RIGHT CONDITIONS
COME TOGETHER. THE WASHINGTON FIRE BURN SCAR IS EXTREMELY SUSCEPTIBLE
TO FLASH FLOODING AND DEBRIS FLOWS AND WILL BE CLOSELY MONITORED. DJ

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...HEAT ADVISORY FROM 11 AM WEDNESDAY TO 8 PM PDT THURSDAY NVZ004.

CA...NONE.
&&

$$

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


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