Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000 FXUS65 KBOU 290951 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 351 AM MDT SUN MAY 29 2016 .SHORT TERM...(Today and tonight) Issued at 351 AM MDT Sun May 29 2016 Westerly flow aloft will become southerly later today and tonight as an upper level low moves across southern California. Water vapor satellite imagery is showing a weak short wave trough over southwest New Mexico. Models show this wave lifting northeast through the day. This wave may help trigger storms over southern parts of the area. Airmass becomes unstable again this afternoon with CAPE values up to 1000 J/kg. Could see slightly higher values over the eastern plains if more moisture advects into the area. Overall, expect similar thunderstorm coverage as yesterday, mainly scattered storms. There will be a little better chance for hail with the storms today because of the increased CAPE. However CAPE and shear will be on lower side, so not expecting severe storms. However, can`t rule out one or two storms just reaching severe threshold over the eastern plains. As far as temperatures go, highs will be 2 to 6 degrees warmer today. .LONG TERM...(Monday through Saturday) Issued at 351 AM MDT Sun May 29 2016 Low amplitude upper level ridge shifts east of Colorado on Monday allowing a long wave upper trough to pass over the region Monday night and Tuesday. The closed low associated with this trough over western Arizona is forecast to weaken as it tracks slowly southeast towards the U.S./Mexico border...while the upper low over western Montana is projected to gain strength as its drops southeast clipping nern Wyoming along the way. Monday should start out dry and mild across the CWA with near zonal flow aloft. Then as temperatures quickly warm should see scattered showers/t-storms blossoming over the high terrain around midday. Should see some of this convection carried off the Front Range during the afternoon tied to a weak disturbance embedded in the wly flow aloft. By evening could see some intensification in these t-storms as they advance into higher dewpts and steeper lapse rates across far eastern sections of the CWA. Cannot rule out a few hail and heavy rain producers in this area during the evening hours. As the northern low passes to our north Monday night...northerly flow on its back side drives a cold front through nern Colorado during the pre-dawn hours. Synoptic scale forcing for ascent appears weak with the upper trough...however during the day Tuesday models show a deepening northeasterly/upslope flow on the plains producing a heavy cloud cover and cooler temperatures as well as areas of light precip. Most of this showery precip is expected to fall east of the Continental Divide late Monday night and much of Tuesday with 12-hour precip totals generally a quarter inch or less. Could see locally heavier amounts in the foothills to the west and southwest of Denver. Farther out on the plains...amounts anywhere from a trace to a tenth of an inch. High temperatures go from around average on Monday to as much as 10-12 degs f below average on Tuesday...with the greatest cooling likely to occur east of the Cont Dvd. Tuesday night and beyond...the upper trough shifts over the northern Great Plains allowing an upper level ridge to gain strength over the Great Basin. Models show this building ridge with its warmer temperatures and drier air migrating eastward over Colorado by Friday. Should see a significant reduction in cloud cover and limited chances for showers/t-storms with its arrival. Guidance indicates highs both days in the low to mid-80s on the plains of northeast Colorado. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 351 AM MDT Sun May 29 2016 Scattered thunderstorms are expected to form over the higher terrain and spread eastward through the afternoon and evening. Best time for thunderstorms in the Denver area is 21z-01z. Will go with a PROB30 in the TAFs at this time. The storms will be capable of heavy rain, small hail and wind gusts to 35 knots. Winds will generally be southerly today at KDEN, except when outflow winds from showers and storms occur. && .BOU Watches/Warnings/Advisories... None. && $$ SHORT TERM...Meier LONG TERM...Baker AVIATION...Meier is the U.S. government's official web portal to all federal, state and local government web resources and services.