textproduct: Elko

KEY MESSAGES

* A few strong thunderstorms possible in parts of Eastern and Central Nevada Tuesday afternoon

* Monsoon weather pattern for Central and Eastern Nevada expected to persist through the week

* Gradual cooling trend through Friday

DISCUSSION

(This evening through next Monday)

WEATHER PATTERN OVERVIEW:

Upper level ridge of high pressure has finally started it eastward slide as an approaching upper level trough digs across the Pacific NW into California. In between these two features southerly flow will continue to bring monsoonal moisture over the silver state. Tuesday afternoon will have a 20% to 30% chance for thunderstorms mainly along the US 50 corridor. These storms will again be slow moving, allowing longer residence time over a given area, meaning higher chances for rain to reach the ground given the dry surface layer as wet storms may produce up to 0.25 or more of rain. Still there will be a few dry thunderstorms that do form especially as storms first form each afternoon, with an elevated risk for ground lightning strikes causing fire starts. Wednesday through Friday, the upper level trough will move through Nevada, Models show that this system will help Nevada out in multiple ways, first dropping temperatures significantly through the end of the week with highs returning to the low 80s to low 90s. Second, it will help channel monsoonal moisture flow increasing chances for wetter storm modes. Finally, the added dynamic cooling and dynamic lift will also help to increase overall precipitation chances. The result will be a 30% to 80% chance for isolated to scattered afternoon and evening thunderstorms and showers. The highest probability will remain across central Nevada, but chances have risen to 40% to 60% of thunderstorms for northern Nevada. Models are now showing better chances for all of northern Nevada to see precipitation this week. There still is a possibility that NW Humboldt county gets missed, but model consensus QPF now shows up to 0.25 of rainfall through Saturday morning with ares of central NV could receive up to 0.75 or more. After Saturday the first upper trough lifts NE into Canada which may lower storm chances a bit over the weekend, but storm chances will average 20% to 40%. Next Monday through Wednesday Models have been inconsistent with the evolution of the upper pattern, and todays solutions are no different. GFS and the ECMWF ensembles have been trading solutions of either another upper trough somewhere over the western US, or the return of the upper level ridge to the four corners or great basin. The one new agreement for the most recent runs is keeping the southerly monsoonal flow. However, given the particular placement of either ridge or trough will dictate how high or low storm and shower chances become for the longer term. So for now will hold over a low 20% to 30% chance for isolated thunderstorms mainly fir central and eastern NV for the start of next week.

FORECAST CONFIDENCE & DEVIATIONS: There is high confidence for chances of isolated to scattered wet with a few dry thunderstorms Through Saturday afternoon for central Nevada.

There moderate confidence for isolated to scattered mix of wet and dry thunderstorms expanding to cover Humboldt and Elko counties Wednesday through Saturday.

There is low confidence in the evolution of the upper pattern after Sunday as models are disagreement as to the strength and location of key upper level features.

AVIATION

VFR conditions look to be the primary flight conditions through Wednesday. Areas of FU will be possible for N NV terminals in the mornings due to regional wildfires with local drops in visibility. For KELY, KTPH, and KENV increasing mid level moisture will bring afternoon VCTS. There will be a low chance of VCSH this evening for KWMC and KBAM as evening convection wanes, but little in the way of impacts to FCs expected. Winds will be breezy Tuesday out of the W at 10KT to 20KT with occasional gusts up to 30KT possible.

FIRE WEATHER

Elevated fire weather concerns possible for northern Nevada Tuesday as breezy west winds of 10 to 20 MPH with a few gust up to 30 MPH possible, will combine with low afternoon RH values. For Central Nevada Tuesday will see a 20% to 40% chance for a mix of wet and a few dry thunderstorms. The main hazard from these storms will be gusty outflow winds up to 50 MPH, Ground lightning strikes, and brief heavy rainfall. Wednesday a upper level storm system will move in from the west which will help bring better mid level moisture, raising storm chances to between 40% and 80% for all zones. Storm chances will continue through at least Saturday afternoon as upper level storm exits to the NE.