textproduct: Reno

KEY MESSAGES

* Late spring like warmth is expected to dominate the region this week into next with temperatures climbing to 15 to 25 degrees above normal.

* The storm track will remain well north of the region, leading to a continued absence of rain or snow alongside typical westerly afternoon breezes.

* Long range signals strongly favor a persistent dry and mild pattern, with no meaningful precipitation expected for at least the next 7 to 10 days.

DISCUSSION

The region is entering a period of significant positive geopotential height anomalies as an unseasonably strong 500-hPa ridge intensifies across the Western US. This synoptic pattern will drive surface temperatures to levels more typical of late May, well ahead of the typical March schedule. Throughout the week, western NV valleys will see a steady climb from highs in the mid-60s Tuesday into the high-70s and eventually low-80s Friday into next week. Keep in mind that for Reno the average first 80 degree day is typically April 30th, with the earliest recorded on March 12, 2007. The first 80 degree day for Reno last year was March 25th, so we are well ahead of schedule if this forecast pans out.

Sierra valleys will follow a similar warming trend, rising from Tuesday's highs in the low-50s to the upper-60s by the weekend. These projected highs represent temperatures roughly 20-25 degrees above normal, with daily records expected to be challenged, tied, or broken starting Friday and continuing through early next week.

This prolonged warmth will accelerate snowmelt, resulting in diurnal surges in river and stream flows. Please be aware of these high flows and stay away from waterways, especially beginning this weekend, as cold and fast-moving water can be dangerous.

Dry conditions will persist as the primary storm track stays deflected to the north, keeping the probability of measurable precipitation nil for the area. Westerly zephyr breezes will make their first appearance this year as temperatures warm through the week. A slightly more pronounced uptick in wind from the west- northwest is expected on Tuesday as a shortwave trough brushes by to the north. While lower-elevation locations like Reno will see forecast gusts around 25-30 mph, 700-hPa winds of 20-25 kt will translate to ridge-top gusts between 40-50 mph Tuesday afternoon.

Looking further out, there is little relief in sight for those hoping for late-winter precipitation as we move deeper into meteorological spring. Current signals point toward an extended dry spell lasting at least through the next 10 days. The 8-14 day outlook from the Climate Prediction Center reinforces this, showing an 80% or greater chance of above-normal temperatures and a strong lean toward below-average precipitation through the third week of March. Given the strength of the ridge and high forecaster confidence, the chances for significant precipitation remain zero for the foreseeable future.

-Johnston

AVIATION

VFR and unseasonably warm conditions will remain the dominant theme across regional terminals throughout the week, with the primary operational concern being a shift to enhanced west- northwest winds between 22Z Tuesday and 03Z Wed. Tuesday's peak gusts are forecast to reach 25-30 kt for western NV terminals and 15-20 kt for Sierra terminals. Elevated FL100 winds may introduce some westerly low-level wind shear for KRNO-KCXP-KMEV along with associated mechanical turbulence during the Tuesday afternoon window.

Diurnal afternoon breezes from the west-southwest at 15-20 kt will prevail for the remainder of the week. Expect mid-to-high level cloud cover to overspread the region late tonight into Tuesday as a weak shortwave brushes to the north. With temperatures steadily increasing into next week, we may see some minor density altitude concerns pop up, especially late this weekend. -Johnston

REV Watches/Warnings/Advisories

NV...None. CA...None.