Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
339 FXUS02 KWBC 040620 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 220 AM EDT Wed Jun 4 2025 Valid 12Z Sat Jun 07 2025 - 12Z Wed Jun 11 2025 ...Heavy rainfall/flash flooding threat from the Southern Plains to the Northeast into the weekend to include a Southern Plains to Mid-South Severe Weather threat... ...Heatwave for the Interior Northwest/West and also the U.S. southern tier, but especially South Texas... ...Compact low to lift along/off the Southeast U.S. late week being monitored by NHC for sub-tropical development... ...Guidance/Predictability Assessment... The latest suite of guidance continued trending toward a better clustered upper level flow pattern evolution through medium range time scales; however there are still some struggles with details for individual systems and the associated local weather weather and hazards. Maintained continuity by utilizing a multi-model blend of the GFS/ECMWF/Canadian/UKMET and GEFS/ECMWF/Canadian ensemble guidance along with favorably supporting guidance from the 01 UTC National Blend of Models. This blend seems to offer a reasonable middle of spectrum depiction of surface system and hazard threats consistent with the more predictable upper flow. ...Weather/Hazards Highlights... A non-tropical low is expected to develop offshore the Southeast coast prior to the extended. The National Hurricane Center is monitoring this feature for the potential to transition into a subtropical or tropical low. Deepest moisture may stay offshore and uncertainty is high, but there is a chance of some heavier rainfall along the coast. Pooled moisture across the central U.S. will help convection fire up along a slow-moving and wavy front that will stretch from the Northeast and Ohio Valley states down to the Southern Plains. Locally enhanced rainfall will be supported thanks to steady advection from the Gulf coupled with shortwave/jet. Conditions will be favorable for hourly rates of 1 inch/hour or greater. WPC has a broad Marginal Risk spanning from the Plains to the Great Lakes/Northeast into the weekend. Within the Marginal is a smaller area highlighted with a Slight Risk of excessive rainfall mainly for Oklahoma, but also into the adjacent counties of Arkansas and southwest Missouri. The southern trailing tail of the elongated boundary will stall and weaken over the southern Plains. Dynamic upper closed low/trough digging into the north- central U.S. from the weekend into early next week will spawn fronto/cyclo genesis, with baroclinicity rejuvenated more broadly again that may act to spread heavy rainfall focus across the Mid- South and Tennessee Valley then down across the Mid- Atlantic and the South/Southeast. Summer heat will build across the Interior Northwest/West and into the Desert Southwest with establishment of mean upper ridging over the weekend into next week. Maximum temperatures over the interior Northwest may range upwards to 20-25F degrees above normal. Areas from south Texas into the Gulf Coast will also experience rising temperatures, cresting upwards of 105F by the weekend over South Texas to push heat index values dangerously upwards to 110-115F. Please take heat safety precautions such as increased water intake and more time in air conditioned areas to avoid heat exhaustion and heat stroke. See weather.gov/heat for more information on safety tips and resources. Campbell/Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$