000
FXUS65 KLKN 162145
AFDLKN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ELKO NV
245 PM PDT TUE SEP 16 2008

.SYNOPSIS...HIGH PRESSURE WILL HOLD ON FOR ONE MORE DAY BEFORE
WEAKENING TONIGHT AHEAD OF A TROUGH OF LOW PRESSURE. WEDNESDAY
WILL SEE SOME THUNDERSTORM DEVELOPMENT AS THE TROUGH MOVES ACROSS
CENTRAL AND NORTHERN NEVADA. ANOTHER LOW PRESSURE SYSTEM WILL
BEGIN TO AFFECT THE REGION THIS WEEKEND.
&&

.SHORT TERM...TONIGHT THROUGH THURSDAY. UPPER RIDGE WHICH HAS
DOMINATED THE WEATHER ACROSS CWA IN RECENT DAYS WILL GIVE WAY TO AN
ACTIVE PATTERN ACROSS THE WESTERN CONUS. AN UPPER TROUGH CURRENTLY
OFF THE CA COAST IS CURRENTLY MOVING ONSHORE AND WILL START TO
AID IN MOISTURE RETURN TO THE AREA. THERE MAY BE A VERY ISOLATED
THUNDERSTORM THIS EVENING ACROSS FAR SW CWA BUT SHOULD JUST SEE AN
INCREASE IN MID AND HIGH CLOUDS THROUGH THE NIGHT. LOW TEMPERATURES
SHOULD BE A LITTLE MORE MILD THAN IN RECENT NIGHTS. WED WILL SEE
PW`S GOING UP TO AROUND 0.50 TO 0.60 INCHES ALONG WITH A LITTLE
INSTABILITY WHICH WILL AID IN THUNDERSTORM DEVELOPMENT. WILL
PROBABLY BE A MIX OF WET AND DRY THUNDERSTORMS GIVEN THE LOW
PW`S...BUT IT IS NOT AUGUST AND TEMPERATURES WILL NOT BE IN THE
90S SO SHOULD AT LEAST GET THE STRONGER STORMS TO PRODUCE SOME
WETTING RAINS. POTENTIAL STILL THERE FOR DRY LIGHTNING EVENT AND
WILL KEEP FIRE WEATHER WATCH GOING. TEMPERATURES TOMORROW WILL BE
ABOUT 5 DEGREES COOLER THAN TODAY WITH BKN-OVC SKIES EXPECTED ACROSS
MANY AREAS BY MID AFTERNOON. LINGERING CLOUD COVER WED NIGHT WILL
LIKELY KEEP LOWS FAIRLY MILD AGAIN WITH DEW POINTS INCREASING INTO
THE 30S ACROSS MAJORITY OF CWA. INSTABILITY WILL BE LIMITED TO
AREAS MAINLY ALONG AND EAST OF THE RUBIES ON THU. TEMPERATURES THU
LOOK SIMILAR TO WED...BUT POSSIBLY A LITTLE COOLER EAST WHERE
THUNDERSTORMS ARE EXPECTED TO REDEVELOP. JMG

.LONG TERM...THURSDAY NIGHT THROUGH NEXT TUESDAY. MODELS BRING A
SHORT WAVE/UPPER LOW INTO NOCAL ON FRIDAY. AHEAD OF THIS
FEATURE...DIFFLUENT FLOW ALOFT AND THE NOSE OF A 60+ KT JET PUSHING
INTO THE REGION WILL SPARK SOME SHOWER AND THUNDERSTORM
ACTIVITY...ESPECIALLY NORTH OF HIGHWAY 50 FRIDAY AFTERNOON AND
EVENING. BEYOND FRIDAY...MODELS DIVERGE QUITE NOTICEABLY WITH
REGARDS TO THEIR HANDLING OF THE SHORTWAVE/UPPER LOW. OPERATIONAL
GFS SEEMS TO BE THE BIGGEST OUTLIER...SHOWING A CLOSED LOW PIVOTING
THROUGH THE CWA ON SATURDAY BEFORE EXITING THE REGION SATURDAY
NIGHT. ECMWF IS MORE PROGRESSIVE WITH THE FEATURE BRINGING AN OPEN
WAVE THROUGH THE REGION FRIDAY NIGHT/SATURDAY MORNING. GFS ENSEMBLE
MEAN SEEMS TO BE SOMEWHAT OF A COMPROMISE BETWEEN THE OTHER TWO
MODELS WITH REGARDS TO TIMING BUT APPEARS TO FAVOR THE ECMWF IDEA OF
BRINGING AN OPEN WAVE THROUGH THE REGION. BASED ON THIS AND INPUT
FROM PREVIOUS SHIFT...WILL CONTINUE TO LEAN MORE TOWARD THE ECMWF
IDEA FOR THIS PACKAGE. THIS SOLUTION BRINGS THE BEST CHANCE OF
PRECIP THROUGH THE REGION FRIDAY NIGHT/SATURDAY MORNING WITH HIGHEST
POPS OVER THE NE CORNER OF THE STATE SATURDAY MORNING. PRECIP THEN
TAPERS OFF FROM WEST TO EAST SATURDAY EVENING AS UPPER TROUGH EXITS
THE REGION. ZONAL FLOW ACROSS THE REGION ON SUNDAY WILL ALLOW FOR
DRY WEATHER. NEXT UPPER TROUGH WILL BRUSH NORTHERN NV EARLY NEXT
WEEK. OPERATIONAL GFS MUCH STRONGER WITH THIS FEATURE THAN THE ECMWF
AND SHOWS A SIGNIFICANT COOL DOWN EARLY NEXT WEEK. NO QUITE READY TO
BITE ON THAT IDEA JUST YET...SO WILL LEAN MORE TOWARD ECMWF IDEA.
HOWEVER...BOTH MODELS DO SHOW A LITTLE PRECIP ALONG THE BORDER WITH
OR/ID SO HAVE ADDED SOME SLIGHT CHANCE POPS. ALSO STARTED TO TREND
HIGH TEMPS DOWN BOTH MONDAY AND TUESDAY AS H5 HEIGHTS FALL AND FLOW
ALOFT BECOMES NORTHWESTERLY. MCGEE
&&

.AVIATION...VFR CONDITIONS EXPECTED TO CONTINUE THROUGH WEDNESDAY.
HOWEVER...ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS NORTHERN AND
CENTRAL NV BEGINNING AROUND 18Z WEDNESDAY AND WILL LINGER INTO THE
EVENING HOURS. ANY THUNDERSTORM THAT DEVELOPS IS EXPECTED TO
REMAIN DRY WITH BIGGEST THREAT BEING GUSTY OUTFLOW WINDS. MCGEE
&&

.FIRE WEATHER...THE DRY...SUNNY CONDITIONS EXPERIENCED RECENTLY WILL
DETERIORATE TOMORROW AS A TROUGH OF LOW PRESSURE MOVES INTO THE AREA.
WITH SOME MOISTURE RETURNING TO THE AREA...SCATTERED THUNDERSTORMS
WILL BE POSSIBLE...MAINLY IN 452...454...AND 455 ON WEDNESDAY.
TEMPERATURES WILL BE ABOUT 5 DEGREES COOLER ON WED THAN TODAY WHICH
COMBINED WITH THE INCREASED MOISTURE SHOULD KEEP RELATIVE HUMIDITIES
OUT OF THE SINGLE DIGITS. THERE WILL BE SOME INSTABILITY
REMAINING OVER EASTERN FIRE ZONES THU SO WILL KEEP MENTION OF A FEW
THUNDERSTORMS FOR THE AFTERNOON AND EVENING. A STRONG UPPER LOW WILL
MOVE ACROSS THE NORTHERN HALF OF THE STATE FOR THE WEEKEND RESULTING
IN A BETTER CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS ALONG WITH
MUCH COOLER...MOIST CONDITIONS. JMG
&&

.LKN WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH IN EFFECT FROM
10 AM PDT WEDNESDAY THROUGH 9 PM WEDNESDAY.

$$