Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1225 AM EDT Fri Jun 15 2018 Valid 12Z Mon Jun 18 2018 - 12Z Fri Jun 22 2018 ...Heavy rains possible for portions of the northwestern Gulf Coast and portions of the central/northern Rockies/plains... ...Hot/humid for portions of the Midwest to the Mid-Atlantic and Southeast early next week... ...Pattern overview and model/guidance assessment/preferences... A stuck upper low over the Great Basin on Monday will slowly weaken as ridging in the east gives way to cyclonic flow through the Great Lakes. To the south, a weakness aloft and a tropical wave at the surface will wring out several inches of rain over the northwest Gulf Coast region during the week. The latest GFS/ECMWF and their ensemble means were in good agreement through the period and a blend of them served well as a starting point. This will take a surface cold front slowly southward out of the Great Lakes on Monday into the Mid-Atlantic by Wednesday but linger back to the west through the southern Plains into the Rockies. The upper low in the west will help draw in moisture from weakening tropical storm Bud through the Rockies into Wyoming/Idaho and southern Montana. ...Weather highlights/hazards... Locally heavy (and regionally modest) rain is probably for the northwestern Gulf Coast as the broad trough/area of disturbed weather moves onshore early in the period. Multi-inch rainfall totals appear possible, focused over portions of southeastern Texas and southwestern Louisiana. To the northwest, the upper low and moisture from (by then) the remnants of Bud will combine to produce several days of wet weather for the central/northern Rockies (with below average max temperatures). Totals of 1-2" may be common for the 5-day total. Temperatures in the east will be well above average (+10 to +20F) to start the medium range (Monday) from the Midwest to the Northeast/Mid-Atlantic with readings well into the 80s/north and 90s/south and approaching 100 in the typical hot spots (near STL and RIC/RDU). Many daily record maxes will likely be tied/broken along the I-95 corridor. With dew points into the upper 60s (north) and low to mid 70s (south), heat indices will be over 100F and close to 110F for some areas. The Pacific Northwest will also see well above average temperatures (especially inland) as they will be located to the northwest of the upper low and coincident with ridging moving out of the northeast Pacific. Temperatures will rise into the 70s/80s west of the Cascades and 90s in the interior of Washington/Oregon. Fracasso WPC medium range forecasts of 500 mb heights, surface systems, weather grids, quantitative precipitation, and winter weather outlook probabilities can be found at: http://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif http://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif http://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html http://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml http://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4