Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 182348
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
548 PM MDT WED MAY 18 2016

.SHORT TERM...(This evening through Thursday night)
Issued at 221 PM MDT Wed May 18 2016

Precipitable water values 130 to 150 percent of normal, weak
steering flow aloft and weak instability contributing to scattered
to numerous showers and thunderstorms this afternoon over the
higher terrain mainly from the Tavaputs to the Flat Tops and
south. Best coverage is over the San Juan Mtns, closer to the
better moisture and cyclonic circulation associated with the upper
level low over central Arizona. Still getting snow above about
11kft, above a level where there is any concern for impacts.
Expect showers to continue over essentially the same locations
through the evening before simmering down overnight.

The upper level low and trough will migrate east into the High
Plains Thursday while shortwave ridging builds over eastern UT and
western CO. Despite some drying, there will still be enough
moisture around for isolated to scattered afternoon convection
over mountains. Expect Thursday to be several degrees warmer than
today.

.LONG TERM...(Friday through Wednesday)
Issued at 221 PM MDT Wed May 18 2016

A large upper level low will sink south and then stall in the
vicinity of the interior Pac NW states by Saturday. We will be in
the tighter gradient region between this low and the ridge of high
pressure over the central U.S. Saturday and Sunday which will
bring a breezy to windy and warm pattern to our region. Cannot
rule out isolated diurnal convection over the higher terrain
Friday and Saturday...but should have a little better coverage on
Sunday as a minor upper level trough moves through. As the upper
level low weakens and moves north, individual shortwave troughs
caught in the broad long wave trough over the western U.s. will
begin to cross the region every 36 hours or so next week.
Precipitable water values will be about half what they are
now...so expect only isolated mainly diurnally driven convection
over the mountains each day. After Saturday, as the region comes
under the trough aloft, temperatures will be 5 to 10 degrees below
normal through the middle of next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 543 PM MDT Wed May 18 2016

Scattered showers and thunderstorms will slowly diminish across
the region this evening with bulk of activity shutting down by
06z. A few storms will drift over the valleys and impact terminal
sites with wind gusts to 30 mph, brief heavy precipitation and
possibly small hail. Brief IFR/MVFR cigs should be expected in the
vicinity of showers with frequent mountain obscuration. Another
round of isolated showers and thunderstorms is expected Thursday
afternoon.

&&

.GJT Watches/Warnings/Advisories...
CO...None.
UT...None.
&&

$$

SHORT TERM...BEN
LONG TERM...BEN
AVIATION...JDC



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