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FXUS65 KREV 300841
AFDREV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
141 AM PDT WED JUL 30 2025
KEY MESSAGES
* SCATTERED SHOWERS AND THUNDERSTORMS RESUME THIS AFTERNOON POSING
A RISK FOR HEAVY RAIN, GUSTY OUTFLOW WINDS, SMALL HAIL, AND
FREQUENT LIGHTNING.
* THUNDERSTORM CHANCES DECREASE TOMORROW AND FRIDAY. HOWEVER, THE
SAME RISKS PERSIST ON BOTH DAYS.
* A DRYING TREND IS EXPECTED THIS WEEKEND WITH AN INCREASE ON
AFTERNOON WINDS.
DISCUSSION
CURRENTLY, THE UPPER TROUGH IS STARTING TO MOVE THROUGH THE
REGION AS SEEN IN WATER VAPOR SATELLITE IMAGERY. THIS IS GENERATING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AS OF 1 AM. THIS
ACTIVITY IS EXPECTED TO CONTINUE OVER THE NEXT FEW HOURS WITH SOME
CELLS POSSIBLY PERSISTING AFTER SUNRISE PER THE MEMBERS OF THE
HREF AND OTHER GLOBAL AND ENSEMBLE MODELS. THE MAIN HAZARD EARLY
THIS MORNING IS GUSTY WINDS AND FREQUENT LIGHTNING.
AS THE TROUGH CONTINUES ITS NORTHEASTWARD TRAJECTORY IT WILL
ENHANCE ITS POTENTIAL VORTICITY, AND COMBINED WITH INCREASING
INSTABILITY DURING THE DAYTIME HOURS RESULTING IN WIDESPREAD
SHOWERS AND THUNDERSTORMS. THE MAIN HAZARDS WITH ANY STORM WILL BE
SMALL HAIL UP TO 1 INCH, FREQUENT LIGHTNING, HEAVY RAIN AND GUSTY
AND ERRATIC WINDS 40+ MPH. THE SLOWER MOTIONS OF STORMS COMBINED
WITH THE HEAVY RAIN THROUGH THE EARLY EVENING HOURS COULD LEAD TO
LOCALIZED FLASH FLOODING. ALSO SOME OF THESE GUSTS COULD LEAD TO
PATCHY AREAS OF BLOWING DUST AND DUST CHANNELS IN THE NV BASIN AND
RANGE.
STORM ACTIVITY DECREASES LATE ON WEDNESDAY EVENING AS THE AXIS OF UPPER
TROUGH MOVES NORTHWARD AND PUSHING MOST OF THE STORM TOWARDS MODOC
AND NORTHERN WASHOE COUNTIES NEAR THE OR BORDER. BY TOMORROW, THE
CHANCES FOR STORMS DROP SIGNIFICANTLY WITH PROBABILITIES AROUND
10-30% MAINLY NORTH OF RENO COVERING NE CA, FAR NORTH WASHOE AND
NORTHWEST PERSHING CO. WE ARE STILL EXPECTING HAZARDS SIMILAR TO
WEDNESDAY, BUT WITH LESS COVERAGE AND LESS MOISTURE ALOFT IT IS
LESS LIKELY. HOWEVER WITH ISOLATED CONVECTION THE RISK FOR DRY
LIGHTNING INCREASES. FOR MORE INFO ABOUT FIRE CONDITIONS PLEASE
LOOK THE FIRE WEATHER SECTION BELOW.
A DRIER AND WARMER SYNOPTIC PATTERN STARTS ON FRIDAY AS THE MAIN
STORM TRACK LIFTS TO OUR NORTH INTO THE PACNW. ALTHOUGH, VERY LOW
CHANCES OF STORMS, LESS THAN 10%, PERSISTS MAINLY IN AREAS NEAR
THE OR BORDER. THE APPROACH OF ANOTHER DEEPER UPPER TROUGH LATE
THIS WEEKEND INTO EARLY NEXT WEEK BRINGS THE RETURN OF GUSTY
WINDS TO THE REGION, ESPECIALLY FOR SUNDAY INTO MONDAY.
AFTERWARDS, THE EXPANSION OF AN UPPER HIGH PRESSURE AREA CENTERED
OVER THE SOUTHERN PLAINS WILL LEAD TO WARMER CONDITIONS MORE
TYPICAL OF EARLY AUGUST.
AVIATION
GENERALLY VFR CONDITIONS CONTINUE THROUGH THE PERIOD. THERE IS A
10-40% CHANCE FOR SHOWERS AND THUNDERSTORMS THIS MORNING, THEN A
30-60% THIS AFTERNOON ACROSS ALL TERMINALS, EXCEPT FOR KMMH WITH
10-20%. THIS ACTIVITY WILL LEAD TO REDUCTIONS IN CIGS AND VIS.
FURTHERMORE, SMALL HAIL, FREQUENT LIGHTNING, HEAVY RAIN AND GUSTY
AND ERRATIC WINDS TO 30-40 KTS ARE LIKELY WITH ANY OF THESE
STORMS. STORMS MOVE NORTH OF MOST TERMINALS BY 3Z WITH CHANCES
DROPPING BELOW 10% AFTER 06Z THIS EVENING.
LOW STORM CHANCES BETWEEN 10-20% RETURN ON THURSDAY AFTERNOON
WITH SIMILAR HAZARDS.
FIRE WEATHER
THE GREATEST CHANCES AND COVERAGE OF THUNDERSTORMS IS EXPECTED
TODAY ACROSS WESTERN NV, THE SIERRA AND NE CA. RAIN AND STORM
CHANCES RANGING FROM 30-60% ARE LIKELY ACROSS MOST OF THE AREA.
THIS BUMP IN STORM ACTIVITY LEADS TO AN INCREASE IN THE POTENTIAL
FOR DRY LIGHTNING AWAY FROM RAIN CORES THIS AFTERNOON AND EVENING.
THE BEST CHANCES FOR THOSE WILL BE IN FAR NORTHERN NV AND NE CA
NEAR THE OR BORDER. CURRENTLY, WE ARE STILL LOOKING AT A 10-20%
CHANCE FOR DRY LIGHTNING. HOWEVER, A DECENT AMOUNT OF MOISTURE
ALOFT MEAN THAT THIS ACTIVITY WILL HAVE PERIODS OF HEAVY RAIN THAT
WILL HELP INHIBIT THE GENERATION OF NEW FIRE STARTS FROM
LIGHTNING. HOWEVER, WE SHOULD KEEP AN EYE OUT AS STORM MOTIONS
START TO INCREASE LATE THIS EVENING, AT THE SAME TIME THAT
CONVECTION FOR THE DAY STARTS TO END.
SHOWERS AND THUNDERSTORMS RETURN ON THURSDAY AFTERNOON, BUT
CHANCES DROP AREAWIDE TO 10-20%. HOWEVER WITH LESS STORM COVERAGE
WE GET BETTER CHANCES FOR NEW LIGHTNING IGNITIONS AWAY FROM RAIN
CORES. BEYOND THURSDAY IT APPEARS THAT WE MOSTLY DRY OUT BUT KEEP
OCCASIONAL 10-15% CHANCES FOR STORMS IN THE AFTERNOON.
NEVERTHELESS, WE ARE EXPECTING AN INCREASE OF AFTERNOON WIND
GUSTS TO 25-35 MPH THIS WEEKEND ACROSS PORTIONS OF THE AREA,
ESPECIALLY FOR WESTERN NV WITH THE NEXT DEEPER UPPER LEVEL TROUGH.
THIS COULD BRING ISSUES WITH RESPECT OF ANY HOLDOVER FIRES AFTER
SEVERAL DAYS OF STORMS ACROSS THE AREA.
REV WATCHES/WARNINGS/ADVISORIES
NV...NONE.
CA...NONE.
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