textproduct: Elko

KEY MESSAGES

* Subtropical moisture will help to fuel afternoon and evening thunderstorms through the middle of next week

* Some showers and thunderstorms could produce brief moderate to heavy rain with the main threat of debris flows on recently burned areas * Cooling trend continues today as mid-level moisture and increasing cloud cover continues its northward trajectory

DISCUSSION

(Today through next Monday)

WEATHER PATTERN OVERVIEW:

One more afternoon and evening of unrestricted monsoonal flow will continue to bring shower and thunderstorm chances for the Silver State, but High pressure shifting west from the plains looks to first limit, then cutoff moisture flow. Monday afternoon and evening there will again be a 20% to 50% chance of isolated to scattered showers and thunderstorms, but these chances drop to 10% to 20% Tuesday, then rise a bit to 10% to 30% Wednesday afternoon and evening. Storm chances look to drop below 10% Thursday into the weekend, the main reason will be the subtropical high pressure ridge now over the southern plains builds west into Arizona. Storm modes through Monday still favor more wet storm modes, but there will still be a chance for a few dry thunderstorms, both as storm motion increases due to increasing southwesterly flow and from mid level moisture decreasing. Tuesday and Wednesday chances for dry thunder will increase, but storm coverage will shift east as drier air returns from the west. Common hazards for storms will include gusty outflow winds up to 50 MPH, ground lightning strikes, and brief heavy rainfall. Thursday through Monday, models may have finally settled on a pattern change. Both the GFS and ECMWF still show that the upper ridge will try and work its way back west, shifting the upper flow back to a WSW direction as it does so. What is interesting is models are now showing that the ridge will stay farther south over the US/Mex border allowing for a longwave trough to set up offshore of the Pacific northwest. This will bring a more westerly mid and upper level flow, which would be dry, but it would also be cooler given the lower forecast heights. Still this is a just a recent agreement from the models, so overall confidence remains mixed for the extended until this consensus holds firm. Temperatures even with the pattern change look to hold in the low 80s to low 90s, with overnight lows ranging into the mid 50s to mid 60s. Winds will be breezy through the weekend and into the new week as winds shift more south to southwest in line with the upper level flow pattern at speeds of 10 to 20 MPH with gusts up to 30 MPH possible. Winds look to shift back to the west to SW Thursday through the weekend.

FORECAST CONFIDENCE & DEVIATIONS: There is high confidence a daily 20% to 50% chance for isolated to scattered showers and thunderstorms for Nevada through Monday.

There is moderate confidence in a 10% to 30 % chance for a mix of isolated dry and wet thunderstorms Tuesday and Wednesday.

There is high confidence in dry conditions returning to the Great Basin Thursday trough Sunday of next week.

There is low-moderate confidence in the upper pattern Thursday through Monday as models now seem to agree on keeping NV under WSW flow between as upper level ridge over Arizona, and a trough off the Pacific NW.

AVIATION

VFR conditions look to be the primary flight conditions through Monday evening. Winds will be out of the south to southwest at 5KT to 15KT with gusts to 25KT possible for all terminals. VCTS will be possible during afternoon and evening hours for KBAM, KEKO, KELY, and KENV as monsoonal flow keeps a 20% to 50% chance for isolated to scattered showers and thunderstorms. Although not likely, a stray VCTS will be possible for KTPH, and KWMC, chances will be near 10% Monday afternoon.

FIRE WEATHER

One last day of unrestricted monsoonal moisture will keep a 20% to 50% chance for isolated to scattered showers and thunderstorms for central and northern Nevada Monday afternoon and evening. Hazards from storms will include gusty outflow winds up to 50 MPH, Ground lightning strikes, and brief heavy rainfall. High Pressure ridge to the east will begin to impinge on moisture flow by Tuesday and Wednesday dropping storm coverage to isolated and storm chances to 10% to 30% for a mix of wet or dry thunderstorms. High Pressure looks to cut off monsoon flow fully by Thursday bringing drier conditions that will last through Monday of next week. Winds will be out of the south to southwest at 10 to 20 mph with gusts up to 30 MPH possible, after Thursday winds shift to west to southwest with similar speeds through the weekend.

LKN Watches/Warnings/Advisories

None.