Damaging Wind in Nevada, July 19, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ELKO NV
158 PM PDT SUN JUL 19 2009

.SYNOPSIS...MONSOON MOISTURE WILL CAUSE ISOLATED SHOWERS AND
THUNDERSTORMS ACROSS THE REGION THROUGH THE END OF THE WEEK. DAYTIME
TEMPERATURES WILL REMAIN ABOVE NORMAL.
&&

.SHORT TERM...TONIGHT THROUGH TUESDAY. AN UPPER-LEVEL RIDGE OF
HIGH PRESSURE IS CURRENTLY SITUATED OVER ARIZONA. THE LATEST WATER
VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH MOVING THROUGH THE PAC NW
THIS AFTERNOON. THIS TROUGH IS BRINGING SOME DRY MID-LEVEL AIR
INTO NORTHERN NV ATTM WHICH IS BLOCKING THE ADVANCE OF SOME OF THE
MONSOON MOISTURE MOVING UP FROM THE SOUTH. BECAUSE OF
THIS...EXPECTING MOST OF TODAYS SHWRS/TSTORMS TO REMAIN OVER CENTRAL
NV HEADING INTO THIS EVENING WITH ONLY ISOLATED SHWRS/TSTORMS OVER
NE NV. WITH ENOUGH WESTERLY FLOW ALOFT OVER NW NV...NOT EXPECTING
ANY SHWRS/TSTORMS AT ALL IN HUMBOLDT COUNTY THROUGH THE EVENING.

THE UPPER RIDGE WILL REMAIN IN PLACE THROUGH TUESDAY...ALLOWING
MONSOON MOISTURE TO CONTINUE TO FLOW INTO NORTHERN AND CENTRAL NV.
WITH SOME INSTABILITY NOTED IN THE MODELS OVER THE REGION BOTH
MONDAY AND TUESDAY AFTERNOONS...WILL KEEP ISOLATED TO SCATTERED
SHWRS/TSTORMS IN THE FORECAST ESPECIALLY OVER CENTRAL AND EASTERN
NV. WINDS ALOFT OVER NW NV SHOULD REMAIN WESTERLY ENOUGH THROUGH
TUESDAY TO KEEP TSTORMS OUT HUMBOLDT COUNTY..EXCEPT AN ISOLATED
STORM OR TWO EAST OF THE SANTA ROSA MTNS.

DESPITE A SUBTLE WEAKENING OF THE RIDGE IN THE NEAR TERM...DAYTIME
TEMPERATURES ARE STILL EXPECTED TO REMAIN ABOVE NORMAL THROUGH
TUESDAY. HIGHS WILL GENERALLY BE IN THE 90S WITH THE HOTTEST
VALLEYS TOPPING THE CENTURY MARK.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. AT 500MB GFS AND EC AGREE
ON HIGH AXIS REMAINING OVER ARIZONA ALLOWING THERMAL TROF TO REMAIN
OVER NEVADA THROUGH THE PERIOD. 12Z GFS FORECASTS MORE LOW LEVEL
MOISTURE AVAILABLE AND INSTABILITY THAN PREVIOUS MODEL RUNS.
THEREFORE HAVE BUMPED POPS UP SLIGHTLY ON THE DAYTIME TEMPERATURES.
EXPECT THUNDERSTORMS TO DIMINISH IN THE EARLY EVENING WITH LACK OF
DAYTIME HEATING AND FROM LACK OF ANY OTHER DYNAMICS AVAILABLE. PWS
AROUND 0.75 INCHES...UNSTABLE AFTERNOON LIS...AND MODERATELY STRONG
CAPES WILL KEEP CONVECTION IN THE FORECAST THROUGH THE EXTENDED.
&&

.AVIATION...UNSETTLED WEATHER WILL LINGER ACROSS THE AREA THROUGH
MONDAY...WITH MAINLY AFTERNOON AND EARLY EVENING TSTMS. CLOUD BASES
SHOULD REMAIN 10K TO 12K FT ABOVE VALLEY FLOORS. VSBYS WILL BE VFR.
WINDS WILL BE LOCALLY GUSTY NEAR THUNDERSTORMS WITH MODERATE
DOWNBURST POTENTIAL.
&&

.FIRE WEATHER...THE GREATEST CONCENTRATION OF THUNDERSTORMS
THROUGH THIS EVENING WILL REMAIN OVER CENTRAL NV...WITH ONLY
ISOLATED COVERAGE OVER NE NV...AND DRY CONDITIONS OVER HUMBOLDT
COUNTY. THE GOOD NEWS FOR THUNDERSTORMS TODAY IS THAT MOISTURE IS
BETTER ENTRENCHED INTO THE DISTRICT THAN YESTERDAY...AS SEEN BY
DEW POINTS RUNNING ABOUT 10 DEGREES HIGHER THAN YESTERDAY. AS A
RESULT...EXPECTING MOST TSTORMS TO BE OF THE WET VARIETY ACROSS
CENTRAL NV THROUGH THE EVENING WITH A MIX OF WET AND DRY ACROSS NE
NV. HOWEVER...THERE STILL CAN BE SOME LIGHTNING STARTS THROUGH THE
EVENING HOURS AS THESE STORMS WILL BE MOVING QUICKLY TO THE
NORTHEAST AND OUTRUNNING THEIR CORES...BUT THE HIGHER RH VALUES
SHOULD HELP TO SUPPRESS THE SPREAD OF ANY LIGHTNING STARTS.

MONSOON MOISTURE WILL HANG AROUND MONDAY AND TUESDAY...AND
PROBABLY EVEN THROUGH THE END OF THIS WEEK...FOR THE THREAT OF
THUNDERSTORMS EACH DAY. THE GOOD NEWS IS THAT THERE SHOULD BE DEEP
ENOUGH MOISTURE OVER THE DISTRICT TO ALLOW FOR SHOWERS AS WELL.
WESTERLY FLOW SHOULD REMAIN STRONG ENOUGH OVER THE NEXT SEVERAL
DAYS TO KEEP THUNDERSTORMS OUT OF HUMBOLDT COUNTY...EXCEPT FOR
MAYBE AN ISOLATED TSTORM EAST OF THE SANTA ROSA MTNS.

WITH AN UPPER-LEVEL RIDGE REMAINING TO OUR SOUTHEAST THIS
WEEK...DAYTIME TEMPERATURES WILL REMAIN ABOVE NORMAL. RH RECOVERIES
WILL REMAIN GOOD ACROSS CENTRAL AND EASTERN NV THANKS TO MONSOON
MOISTURE REMAINING IN PLACE. RH RECOVERIES WILL BE FAIR TO POOR
OVER HUMBOLDT COUNTY.
&&

.LKN WATCHES/WARNINGS/ADVISORIES...NONE.

&&

99/87/87/99