Extended Forecast Discussion NWS Weather Prediction Center College Park MD 227 AM EDT Fri Jul 02 2021 Valid 12Z Mon Jul 05 2021 - 12Z Fri Jul 09 2021 ...Threat of heavy rain for Florida and the Southeast Coast early to middle next week as Tropical Storm Elsa potentially impacts the region... ...Threat of repeating heavy rain over southern Texas as low pressure persists through much of next week... ...Overview... A summer-like pattern sets up for next week as a strong upper ridge sets up over the Desert Southwest to the Four Corners states, a weak upper trough/low develops over Texas move across the south-central CONUS, while the main jet stream/westerlies meander over the northern U.S. and southern Canada. Additionally, Tropical Storm Elsa has the potential to cross Florida and move up Southeast Coast early to midweek. ...Guidance/Predictability Evaluation... Guidance is pretty agreeable with the overall pattern (with the main exception for the track/timing/strength of Elsa) through midweek. A deterministic general model blend was able to be used for Monday and Tuesday. The 12Z CMC was removed by late Tuesday as it had a stronger upper low in the Eastern Pacific offshore of the Pacific Northwest with a stronger trough over the south-central CONUS resulting in a stronger and faster Elsa. There were some minor differences with northern stream shortwave troughs, which were muted a bit by transitioning to a blend favoring more of the agreeable GEFS and EC ensemble means later next week. Guidance is quite variable in terms of the track and strength of Elsa. The 12Z ECMWF continues to weaken the system by Hispaniola. Meanwhile, the 18Z/00Z GFS take a stronger Elsa into the eastern Gulf of Mexico before crossing the Florida peninsula and moving up the Southeast Coast. Run-to-run timing differences are noted with the 00Z run now slower than the 18Z. The 12Z and 00Z CMC remain the fastest solution with a stronger system through Florida like the GFS - the 00Z CMC has shifted farther east than the 12Z. The 00Z UKMET remains similar to the GFS, with the system entering the eastern Gulf of Mexico on Tuesday, but the UKMET continues to weaken the system before making any US landfall. Thus, uncertainty remains rather high with Elsa though a decent heavy rain threat is present for Florida and possibly the Southeast Coast. The WPC QPF forecast followed the NHC track, which remains closer to the recent GFS and UKMET. ...Weather Highlights/Hazards... An upper low/trough sets up over Texas making for a heavy rain threat there each day of the next work week with multi-inch totals likely. Farther west, late-day monsoonal type showers and thunderstorms are likely Monday into Wednesday over the Central/Southern Rockies. Periods of rain are forecast along and ahead of a front from the north-central to northeastern CONUS. Heavy rainfall, flooding, and high winds are potential threats where Elsa tracks. Timing and strength of Else have considerable uncertainty, but there is a heavy rain threat for portions of the Florida Peninsula Tuesday and across the Georgia and Carolina coast Wednesday with Elsa. The heat wave now looks to persist over the western CONUS through next week as ridging lingers, restrengthens with max temperature anomalies of 10 to 20 degrees above normal for the Northwest with some daily record high temperatures mostly in the Great Basin. Temperatures will generally be a few degrees cooler than average in the south-central U.S./Texas through the week with cloudiness and rain from the persistent upper level disturbance there. Jackson WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml