Extended Forecast Discussion NWS Weather Prediction Center College Park MD 413 PM EDT Tue Jun 02 2020 Valid 12Z Fri Jun 05 2020 - 12Z Tue Jun 09 2020 ...Heavy rain possible for the Gulf Coast near and ahead of Tropical Storm Cristobal... ...Warm temperatures in the West will cool after Friday, while the central U.S. stays hot... ...Overview and Guidance/Predictability Assessment... In the midlatitudes, the medium range period will begin Fri with upper ridging across the Intermountain West and Plains, while an upper low offshore of southern California should combine with another upper low tracking southeastward toward the Pacific Northwest to create an anomalously deep trough over the West early next week. 00Z/06Z model guidance ended up in reasonably good agreement in the early part of the period, despite run-to-run continuity issues, so a blend of multiple operational models was used. By Sun, the upper high is expected to pinch off to the north of Tropical Storm Cristobal tracking northward across the Gulf. This could cause a bit of slowing of Cristobal after a slow beginning in the short range as well. Model clustering is fairly good with the track of Cristobal toward the western-central Gulf Coast, but the timing is somewhat uncertain given the upper high and other factors. The main exception was the 00Z UKMET, which had a track somewhat east of other guidance. The overall pattern should move slowly eastward early next week, and cool troughing will affect the Eastern Seaboard as well. The 00Z CMC looked out of sync by Mon, but the 00Z/06Z GFS and 00Z EC deterministic runs were able to be used in the mass fields blend along with their means through day 7. ...Weather/Hazard Highlights... Tropical moisture is expected to stream into the Gulf coast even ahead of Cristobal, reaching the vicinity of a frontal zone across the Southeast and creating the potential for heavy rainfall first for the central and eastern Gulf Coast into Florida and the Southeast. Then as Cristobal approaches, heavy rain should focus more along its track over the Lower Mississippi Valley and eastern Texas Mon-Tue. Multiple inches of rainfall are expected to accumulate along the Gulf Coast. Showers and thunderstorms are possible along the Eastern Seaboard late this week in the vicinity of frontal boundaries. Ahead of the deep Western trough, a frontal system will push eastward across the western half of the nation through the period. Locally enhanced precipitation is possible along and behind the system, and some snow is even possible in higher elevations of the Cascades and Northern Rockies given the depth of the upper trough. Temperature-wise, the West will start out hot Fri with widespread high temperature anomalies of 10 to 20 degrees above average, but will cool quickly as the upper trough comes overhead. Maximum temperatures should flip to 10 to 20 degrees below normal over the Intermountain West to Northern/Central Rockies, while lows could be a few degrees below average. Above normal temperatures are forecast to persist in the Plains, however. In particular, the south-central High Plains should have highs 15+ degrees above normal late week into the weekend. A sizable area of plus 5-15 degree anomalies should continue over the Plains into early next week. Over the East, temperatures should become near normal after short range/Fri heat as cool high pressure builds in. Tate Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php Hazards: - Heavy rain across portions of the Middle/Lower Mississippi Valley, the Ohio/Tennessee Valleys, the Southeast, and the Southern Plains, Mon-Tue, Jun 8-Jun 9. - Heavy rain across portions of the Southeast, and the Lower Mississippi Valley, Sat-Mon, Jun 6-Jun 8. - Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Northern Plains, the Northern Rockies, the Middle Mississippi Valley, the Mid-Atlantic, the Northern Great Basin, the Southeast, the Great Lakes, and the Ohio Valley. - Flooding likely across portions of the Middle Mississippi Valley and the Northern Rockies. - Much above normal temperatures across portions of the Central/Southern Plains, the Northern/Central Great Basin, and the Northern/Central Rockies, Fri, Jun 5. - Much above normal temperatures across portions of the Central Rockies, and the Central/Southern Plains, Sat-Mon, Jun 6-Jun 8. 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