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536
FXUS65 KREV 232126
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
226 PM PDT WED APR 23 2014

.SYNOPSIS...
RIDGE OF HIGH PRESSURE SLIDES EAST TONIGHT AS CLOUDS BEGIN TO
INCREASE FROM THE WEST. LIGHT PRECIPITATION STARTS TO DEVELOP LATE
THURSDAY ACROSS THE NORTHERN PART OF THE AREA, THEN SPREADS SOUTH
BY EARLY FRIDAY. ANOTHER STRONG COLD FRONT WILL MOVE THROUGH THE
REGION FRIDAY, BRINGING WELL BELOW AVERAGE TEMPERATURES AND THE
CHANCE FOR RAIN AND SNOW AS WELL AS HIGHER ELEVATION TRAVEL
IMPACTS. HIGH PRESSURE RETURNS EARLY NEXT WEEK FOR MUCH WARMER AND
DRIER CONDITIONS.

&&

.SHORT TERM...
SHORT WAVE RIDGE OVER THE REGION TODAY BEGINS TO DRIFT EAST
TONIGHT AS AN UPPER LOW NEAR 45N 149W MOVES TOWARD THE COAST.
THERE REMAIN QUESTIONS ABOUT THE TRACK AND SPEED OF THE SOUTHERN
END OF THE TROUGH ASSOCIATED WITH THIS LOW THROUGH FRIDAY. THE GFS
AND NAM ARE STILL PROGRESSIVE WITH THE SYSTEM WHILE THE ECMWF
PERSISTS IN TRYING TO DEVELOP A CLOSED LOW AND DROP IT SOUTHEAST
THROUGH CENTRAL CA FRIDAY...SLOWING THE PROGRESS OF THE SYSTEM.

EITHER WAY WINDS WILL INCREASE AHEAD OF THE TROUGH THURSDAY AND
THURSDAY NIGHT. WITH INCREASED CLOUDS THURSDAY THE THERMAL
GRADIENT SHOULD BE LIGHTER THAN THE PREVIOUS SYSTEM AND MID LVL
WIND SPEEDS ARE NOT QUITE AS STRONG. SO...WHILE WINDS WILL BE
BREEZY FROM LATE THURSDAY INTO THURSDAY NIGHT...GUSTS SHOULD REMAIN
BELOW 50 MPH MOST LOCATIONS. SOME WIND PRONE AREAS MAY SEE A BRIEF
PERIOD OF GUSTS TO NEAR 55 MPH THURSDAY EVENING...BUT THESE SHOULD
BE SHORT LIVED. LAKE WIND ADVISORIES ARE LIKELY TO BE NEEDED
THURSDAY NIGHT. FOR NOW HAVE HELD OFF ISSUING ANY ADVISORIES TO
LET SUBSEQUENT SHIFTS REFINE THE WINDS A BIT MORE.

SHORT RANGE MODELS ARE STILL A BIT INCONSISTENT IN DEVELOPING THE
HEAVIEST QPF WITH THE SYSTEM THURSDAY NIGHT THROUGH FRIDAY. THERE
IS ALSO SOME QUESTION REGARDING THE DEVELOPMENT OF A CLOSED LOW.
THE MODELS ALL SHOW A NORTH TO SOUTH ORIENTED JET THAT WOULD ARGUE
FOR DIGGING A LOW INTO THE BASE OF THE TROUGH...BUT ONLY THE ECMWF
SHOWS THIS SOLUTION. IF IT IS CORRECT THE HEAVIEST PCPN WILL BE IN
MONO COUNTY. THE NAM AND GFS HAVE HEAVIER PCPN ALONG THE SIERRA
CREST IN THE TAHOE BASIN...BUT DURING THE DAY TIME HOURS FRIDAY.
THIS TIMING WOULD MAKE ACCUMULATING SNOWS DIFFICULT BELOW ABOUT
7500 FT IN LATE APRIL. HAVE INCREASED THE QPF A BIT ALONG WITH
THE POPS OR FRIDAY...BUT HAVE HELD SNOW ACCUMULATION FAIRLY
STEADY. SINCE THERE IS QUESTION REGARDING THE EVOLUTION OF THIS
SYSTEM AND HOW MUCH SNOW COULD ACCUMULATE...WILL WAIT ON ANOTHER
RUN OR TWO OF MODELS TO ISSUE ANY WINTER ADVISORIES. MONO COUNTY
MAY HAVE THE BEST SHOT AT ACCUMULATIONS AS THERE IS A BETTER
CHANCE AT SNOW THERE FRIDAY NIGHT.

TO THE EAST HAVE HELD POPS AND QPF FAIRLY LOW THROUGH FRIDAY GIVEN
THE ORIENTATION OF THE JET NOT PROMOTING SPILL OVER. AS THE TROUGH
AXIS MOVES OVER FRIDAY EVENING POPS SHOULD INCREASE IN WRN NV WITH
SHOWERS DEVELOPING. THOUGHT ABOUT THE THUNDER POSSIBILITY...BUT
INSTABILITY PARAMETERS LOOK BETTER WEST OF THE CREST.

SHOWERS LINGER INTO SATURDAY AND SATURDAY EVENING WITH FLOW ALOFT
BECOMING NORTHWEST. AFTER A COOL DAY FRIDAY...TEMPERATURES SHOULD
START TO REBOUND BY SATURDAY. 20

.LONG TERM...
A WEAK DISTURBANCE WILL PROVIDE CLOUDY CONDITIONS AND LOW CHANCES
FOR SHOWERS ON SUNDAY ACROSS FAR NORTHEAST CALIFORNIA AND NORTHWEST
NEVADA. THIS WILL BE FOLLOWED BY A DRIER AND WARMER PATTERN HEADING
INTO NEXT WEEK AS A RIDGE BUILDS ACROSS THE WEST COAST.

OVERALL FEW CHANGES IN THE EXTENDED FORECAST WITH JUST SOME SLIGHT
REDUCTIONS IN POPS ON SUNDAY. LATEST GUIDANCE IS LESS AGGRESSIVE ON
PRECIPITATION WITH ENSEMBLES SHOWING SUPPORT FOR LOWER QPF BUT ONLY
LIGHT AMOUNTS EXPECTED (A FEW HUNDREDTHS). THEN INTO EARLY NEXT WEEK
MODELS SHOWING GOOD AGREEMENT IN ESTABLISHING A RIDGE ACROSS THE
WEST COAST. THIS WILL WARM TEMPERATURES BACK INTO THE MID 70S TO NEAR 80
FOR WESTERN NEVADA WITH 60S TO LOW 70S FOR SIERRA VALLEYS. LIGHT
WINDS AND MOSTLY CLEAR CONDITIONS WILL PREVAIL WITH THE BUILDING
RIDGE. FUENTES

&&

.AVIATION...
VFR CONDITIONS THROUGH THURSDAY WITH INCREASING WINDS FROM AN
APPROACHING SPRING STORM. WINDS ACROSS THE RIDGES WILL INCREASE
AFTER 12Z THURSDAY MORNING WITH MOUNTAIN WAVES AND TURBULENT
APPROACHES TO THE SIERRA AND WESTERN NEVADA TERMINALS. PEAK GUSTS OF
30-40KTS ARE POSSIBLE AT THE SURFACE. RAIN/SNOW WILL MOVE INTO AREAS
NORTH OF SUSANVILLE-GERLACH THROUGH THURSDAY AFTERNOON.

THIS SYSTEM WILL TRACK SOUTH FOR FRIDAY WITH A PERIOD OF MODERATE TO
HEAVY SNOW LIKELY IN THE SIERRA. AT TRK AND TVL, SNOW SHOULD EASILY
ACCUMULATE ON AIR FRAMES AND ELEVATED SURFACES WITH AN INCH OR TWO
POSSIBLE ON RUNWAYS. RAIN/SNOW WILL ALSO SPREAD INTO WESTERN NEVADA
FRIDAY THOUGH ACCUMULATIONS ARE UNLIKELY AT THIS TIME. BRONG/FUENTES

&&

.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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