Weather Service Report


575 
FXUS65 KGJT 160250
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
850 PM MDT Sun Jul 15 2018

.UPDATE...
Issued at 850 PM MDT Sun Jul 15 2018

No additional heavy rain is expected across southwestern Colorado
this evening...therefore we have cancelled the Flash Flood Watch 
early for the San Juans. Storms still on track to fire up again 
late morning on Monday, with heavy rain a threat to the 416 burn 
scar after noon and through the evening hours on Monday.

&&

.SHORT TERM...(Tonight through Monday night)
Issued at 304 PM MDT Sun Jul 15 2018

Showers and thunderstorms will continue over the San Juan mountains,
the La Sal and Abajo mountains this evening. This was right where
the best storm development was expected due to much less cloud
cover early today compared to the rest of eastern UT and western CO.
Flash Flood Watches continue until midnight tonight for much of
southwest CO, the 416 fire scar. The Flash Flood Watch for the  
Lake Christine fire burn scar was cancelled as drier more stable
air over northern and central CO inhibited storm growth.

Monday will see drier air moving across much of the forecast area
which will significantly decrease rain chances, with strong model
consensus. More moisture will remain over the San Juan mountains 
though and enough that moderate thunderstorms will still be able 
to produce enough rain to cause mud and debris slides on 416 Fire 
burn scar. A Flash Flood Watch is in effect for Monday Noon to 
midnight for the 416 burn scar area.

.LONG TERM...(Tuesday through Sunday)
Issued at 304 PM MDT Sun Jul 15 2018

The good monsoonal plume appears to get temporarily cut off by
high pressure over the southern portions of the Great Basin and
the southwest U.S. Much of it is forced west and south of the 
area through Wednesday. Enough residual low level moisture should 
remain for isolated to scattered afternoon and evening 
thunderstorms over the mountains. Still the monsoon signal and 
season continue over northwestern Mexico just waiting for the next
favorable orientation of pressure systems over the western and 
central U.S to bring it surging north. That seems to occur 
Thursday evening through Sunday as the Great Basin high slides 
east and over Four Corners. Though this isn't the ideal 
orientation for a strong monsoonal surge over CO and UT, it is 
seems to have enough SW flow just west of the high center to draw 
the plume north and into our area again through the weekend. 

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 528 PM MDT Sun Jul 15 2018

Southwest Colorado TAF sites still impacted by showers and
thunderstorms early this evening but these storms should be on the
decrease through sunset. KDRO is most likely to be impacted
through 16/02Z as storms are just upstream of the airport. Impacts
overall appear minor at this time as winds gusts have been 20kts
or less most areas though rainfall may temporarily drop vsby to
MVFR. Drier air moves in through sunrise and any concerns will be
at KTEX and KDRO for Monday. 


&&

.HYDROLOGY...
Issued at 304 PM MDT Sun Jul 15 2018

Areas of heavy monsoonal showers and thunderstorms will continue
until about midnight tonight with decreasing showers overnight.
Less moisture is expected over much of the area Monday though
southwest CO will still see some moderate rainfall out of some
storms. A Flash Flood Watch continues until midnight for much of
Southwest CO and the 416 Fire burn scar area. Flooding and mud
slides have been reported this afternoon in a few flood prone 
areas of southwest CO. A Flash Flood Watch is in effect for the
416 Burn Scar area Monday afternoon and evening. The Flash Flood
Watch for the Lake Christine Fire burns scar area for this
afternoon and evening has been cancelled as much less
thunderstorm development has occurred over central and northern 

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Flash Flood Watch from Monday afternoon through Monday evening 
     for COZ019-022.

UT...None.
&&

$$

UPDATE...JAM
SHORT TERM...CC
LONG TERM...CC
AVIATION...TGJT
HYDROLOGY...CC

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Western Regional Climate Center, wrcc@dri.edu