QUICK LOOK AT COMPUTER MODELS /WHATS AVAILABLE/ MAINTAINS A SLIGHTLY
MORE SOUTHEAST TRACK OF UPPER TROUGH AS IT MOVES INTO NEVADA
TODAY/TONIGHT. DYNAMIC LIFT EXPECTED TO TO BE GREATEST ACROSS THE
NORTHERN AND EASTERN FLANKS OF THIS SYSTEM AS IT REACHES FULL
STRENGTH TONIGHT...BEST AREA FOR MOST WIDESPREAD PRECIP CONTINUES
TO PEG THE FAR NORTHWEST AND WESTERN FRINGE OF THE STATE DURING
THAT TIME. CLOSED NATURE OF LOW AND INFLUENCE OF DOWNSTREAM RIDGE
COMBINED WILL HAVE A NEGATIVE IMPACT ON THE STRENGTH OF THE SYSTEM
OVER THE NEXT 48 HOURS HOWEVER. STRATIFORM PRECIP OVER THE
NORTHWEST/WEST UTAH TONIGHT WILL LIKELY TRANSITION INTO A MORE SHOWERY
AND CONVECTIVELY DRIVEN EVENT...WITH AREAL COVERAGE OF PRECIP
MOST LIKELY ACROSS CENTRAL AND SOUTHERN PORTIONS OF UTAH COINCIDENT WITH
GREATEST INSTABILITY AND COLD CORE TRACK.
BELOW IS A FORECAST MODEL THAT SHOWS PRECIPITATION, NOTICE ON THE
LOOP BELOW THAT MOST OF THE PRECIP. STAYS OVER THE WEST DESERT,
SO TIME WILL TELL IF WE GET A GOOD RAIN EVENT OR JUST A FEW SHOWERS
WHICH IS THE WAY I AM LEANING TOWARDS NOW.
There is a weak closed low that is sitting over the coast of
Washington, which results from a weather feature that meteorologists
call a coherent tropopause disturbance, or CTD. A CTD is a
localized cyclonic vortex, which is associated with counterclockwise
rotation in the Northern Hemisphere and is strongest at the tropopause.
The tropopause separates the stratosphere from the troposphere.
The CTD and closed low move into Nevada by tomorrow morning
A different perspective at this time is provided below by a 3-D colored
representation of the tropopause, with cool colors indicating a lower
tropopause and warm colors indicating a higher tropopause. Note how the
tropopause is locally depressed where the CTD and closed low are found
over Nevada.
Thus, as the low approaches Utah, temperatures in the upper-troposphere
will fall. This, combined with large-scale rising motion ahead of the low, will act to destabilize the atmosphere and initiate some showers
and thunderstorms. As a result, although we are still under the
influence of a large-scale upper-level ridge, we have a chance of some
isolated showers and thunderstorms today and scattered showers and
thunderstorms tomorrow.
