![\"\"](\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2018\/08\/FTO-20180816.png\")
<\/a><\/p>\nAs pointed out in the FTB this morning, the remnants of the last trough<\/span> are now over the Midwest and the system will continue to push eastward. In its wake, an arid air mass has pushed into northern Colorado. Beginning Friday morning, increased moisture will arrive to this region (east of the Divide<\/span>) as SE surface winds return with an approaching shortwave<\/span>. With weak surface winds aloft, there is an Elevated Threat to start this FTO period. Moisture trapped under the ridge over southwest Colorado will again spark another round of afternoon thunderstorms favoring the San Juan and southern Central Mountains on Friday.<\/p>\n On Saturday, the upper-level trough<\/span> marked in the water vapor imagery below begins to move inland and displace\/breakdown the weak ridge. Positive vorticity advection<\/span> (PVA) on the east side of the trough<\/span> will provide a large amount of lift for widespread<\/span> thunderstorms. Early Saturday, showers will begin over the Northwest Slope and increase north to south by early afternoon. By the mid-afternoon hours, the trough<\/span> will arrive to the eastern mountains where upslope flow and daytime heating are occurring. A line of convergence is expected to produce a strong line of thunderstorms over the adjacent plains by early afternoon with plenty of thunderstorm action over the higher terrains as well. Threats include large hail, damaging winds and heavy rainfall. While moisture over the mountains won’t be quite as deep as over the adjacent plains, rain rates are expected to be high enough to cause flooding concerns near recent burn scars. Steering winds should be quick with the mid-level jet streak<\/span>, so widespread<\/span> flooding over the mountains is not a concern at this time. Though these details may change over the next couple of runs. Dew points<\/span> over the eastern plains could reach 60F, so there are flooding concerns despite swift southeast movement of the storms.<\/p>\n Sunday, activity looks to calm down a bit as the trough<\/span> drops a cold front over the state. This is expected to draw in some dry air with northerly flow, cap<\/span> convection<\/span> and bring much cooler temperatures. While no strong convection<\/span> is forecast, there is a chance for some stratiform rain associated with the front. To start next week, the ridge begins to build north of Colorado once again. A second trough<\/span> forms over the Pacific Northwest, but at this time, the models lift the trough<\/span> north. This should keep northwesterly flow over the state and increase the chances for upper-level disturbances to pass through the state each afternoon through the end of the week. The big question each day will be the availability of low-level moisture. At this time there should be enough residual moisture under the ridge to the west and daily southeasterly flow to the east that mountain convection<\/span> will be possible each afternoon. There is not enough confidence at this time to forecast anything more than No Apparent Threat.<\/p>\n Quite a jump in Precipitable Water<\/span> (PW<\/span>) for Denver starting tomorrow as southeasterly surface flow returns. Not much change for western Colorado. With steering flows aloft being light again tomorrow, burn scars will be monitored closely. On Saturday, PW<\/span> begins to drop off statewide with the exception of the far eastern plains. Western movement of the 500mb high is expected to decrease rainfall chances over western Colorado until next week when the ridge begins to build and the 500mb high shifts east again. Not much confidence in low-level moisture after Tuesday as the GEFS shows a lot of variability both east and west. This likely has to do with how strong the ridge rebuilds and the location of its axis. All details that are nearly impossible to pinpoint this far out. Nonetheless, there should be enough moisture for daily rounds of thunderstorms with the diurnal flow.<\/p>\n<\/a><\/p>\n