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000
FXUS65 KREV 172221 CCA
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
245 PM PDT FRI MAY 17 2013

.SYNOPSIS...

LOW PRESSURE OVER THE NORTHWEST WILL KEEP A FEW SHOWERS THIS EVENING
MAINLY EAST OF RENO. TEMPERATURES WILL WARM TO NEAR NORMAL THIS THE
WEEKEND AS WEAK HIGH PRESSURE BUILDS INTO THE WEST. ANOTHER DEEP
AREA OF LOW PRESSURE DROPS INTO THE REGION BY THE MIDDLE OF NEXT
WEEK BRINGING WIND, COOLER TEMPERATURES, AND CHANCES FOR SHOWERS.

.SHORT TERM...

THE UPPER TROUGH CONTINUES TO PUSH ACROSS NEVADA THIS AFTERNOON,
WITH A FEW ISOLATED SHOWERS MAINLY EAST OF RENO. A DECENT CAPPING
INVERSION HAS KEPT CONVECTION ON THE SHALLOW SIDE TODAY. DRIER AND
MORE STABLE AIR IS ALSO WORKING IT`S WAY INTO THE AREA THIS
AFTERNOON AS WELL. ISOLATED SHOWERS ARE EXPECTED TO CONTINUE THROUGH
SUNSET, THEN DIMINISHING OVERNIGHT.

AS WE GO INTO SATURDAY, ANOTHER SHORTWAVE WILL DROP THROUGH THE PAC
NW AND INTO NORTHERN CA/NV. THIS WILL HELP TO INCREASE THE
TEMP/PRESSURE GRADIENTS WITH NORTHWEST GUSTS AROUND 30 MPH NORTH OF
PYRAMID LAKE. THESE NORTHWEST WINDS ON PYRAMID LAKE WILL BE NEAR
LAKE WIND ADVISORY CRITERIA, ALTHOUGH JUST SHY. BREEZY CONDITIONS
WILL LAST WELL INTO SATURDAY EVENING AND OVERNIGHT AS THE COOL FRONT
MOVES THROUGH THE FORECAST AREA. MODELS HAVE BEEN SHOWING MORE
SHOWER ACTIVITY AHEAD ON SATURDAY AFTERNOON/EVENING FOR NORTHERN
LASSEN, NORTHERN WASHOE AND PERSHING COUNTIES. WENT AHEAD AND ADDED
A SLIGHT CHANCE OF SHOWERS TO THOSE AREAS, ALTHOUGH VERY LITTLE
RAINFALL IS EXPECTED.

SKIES CONTINUE TO CLEAR OUT ON SUNDAY AS DRIER AIR WORKS INTO THE
REGION. CONTINUED NORTHWEST FLOW WILL KEEP TEMPERATURES NEW NORMAL
THROUGH SUNDAY AS WELL WITH HIGHS IN THE LOW-MID 70S IN WESTERN
NEVADA AND LOW-MID 60S IN THE SIERRA.  HOON

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

NEXT WEEK WILL BEGIN WITH SLIGHTLY ABOVE NORMAL TEMPS AND DRY
CONDITIONS WITH LIGHT WINDS AS SHORTWAVE RIDGE MOVES ACROSS CA-NV ON
MONDAY.

BY MIDWEEK, A CHANGE TO THE PATTERN IS EXPECTED AS A STRONG LOW
PRESSURE DROPS SOUTH ALONG THE WESTERN CANADA COAST TO THE NORTHWEST
US. THE MAIN EFFECTS ON TUESDAY WILL BE A SHARP INCREASE IN WINDS
AHEAD OF THE LOW. FOR NOW THE WIND FORECAST WILL INDICATE POSSIBLE
GUSTS UP TO 40 MPH BY LATE AFTERNOON/EARLY EVENING, BUT SOME AREAS
ESPECIALLY NORTH OF HIGHWAY 50 COULD SEE EVEN STRONGER GUSTS. TEMPS
ON TUESDAY WILL BEGIN TO TREND LOWER FOR THE SIERRA AND NORTHEAST
CA-NORTHWEST NV, BUT IN WEST CENTRAL NV BASIN FROM HIGHWAY 95
EASTWARD THE HIGHS SHOULD PUSH ABOVE 80 DEGREES. MOISTURE AND
INSTABILITY DO NOT APPEAR TO BE SUFFICIENT FOR DEVELOPING ANY
CONVECTION ALONG THE COLD FRONT.

FOR WEDNESDAY, WINDS WILL SHIFT TO THE NORTH WITH TEMPS DROPPING BY
10 TO 15 DEGREES COMPARED TO TUESDAY. THE AIR MASS WILL ALSO BE
DRIER BEHIND THE FRONT, WITH A BRIEF PERIOD OF VERY LOW HUMIDITY
POSSIBLE IN HIGHER ELEVATIONS EARLY THURSDAY MORNING.

THROUGH MIDWEEK, MODEL GUIDANCE IS IN RELATIVELY GOOD AGREEMENT WITH
TIMING AND MOVEMENT OF THE UPPER LOW AND COLD FRONT, SO FORECAST
CONFIDENCE UP TO THIS POINT IS ABOVE AVERAGE. FOR THURSDAY AND
FRIDAY, SCENARIOS BEGIN TO DIVERGE, SO FORECAST CONFIDENCE DECREASES
TO BELOW AVERAGE BY THE END OF NEXT WEEK.

LATER NEXT WEEK, THE ECMWF PUSHES THE CENTER OF THE LOW FARTHER
SOUTH INTO NORTHERN CA AND BRINGS LIGHT PRECIPITATION INTO NORTHEAST
CA-NORTHWEST NV BY THURSDAY. 700 MB TEMPS ALSO COOL OFF TO AROUND -8
C SO SNOW LEVELS COULD BRIEFLY DROP TO NEAR 5000 FT NEAR THE OREGON
BORDER. IN CONTRAST, THE GFS KEEPS THE MOISTURE CONFINED TO NORTHERN
OREGON AND LIFTS THE COOLER AIR MASS NORTHWARD MUCH MORE QUICKLY.
700 MB TEMPS IN THE SAME AREAS NORTH OF SUSANVILLE-GERLACH ON
THURSDAY ARE UP TO NEAR 0 C. THEN ON FRIDAY, THE ECMWF SLOWLY LIFTS
THE LOW NORTHWARD, WHILE THE GFS DROPS PRECIP POTENTIAL WITH BOTH
SCENARIOS IS SPARSE AT THIS TIME WITH GREATER DIFFERENCES BECOMING
MORE EVIDENT DURING THE MEMORIAL DAY WEEKEND.

GIVEN THAT THE ECMWF HAS SEEMED TO BE A STEP AHEAD OF OTHER GUIDANCE
WITH RECENT COLD FRONT PASSAGES FROM THE NORTH, THE FORECASTED
TEMPS, PRECIP POTENTIAL AND WINDS FOR NEXT THURS-FRIDAY WILL LEAN
TOWARD THE COOLER AND WETTER SCENARIO PRESENTED BY THE ECMWF. AT
THIS TIME THE PROBABILITY OF PRECIP REACHING THE RENO OR TAHOE
REGIONS THRU NEXT FRIDAY IS LOW. MJD

&&

.AVIATION...

A FEW LINGERING SHOWERS THIS EVENING BEFORE 04Z FOR AREAS EAST OF
KRNO, INCLUDING KNFL AND KLOL. BREEZY WEST WINDS WILL ALSO CONTINUE
THROUGH THIS EVENING THEN LIGHTER WINDS OVERNIGHT. BY SATURDAY,
ANOTHER FRONT WILL BRING BREEZY CONDITIONS NORTH OF RENO WITH GUSTS
AROUND 25KT. HOON

&&


&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

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