Quantitative Precipitation Forecast
Issued by NWS
Issued by NWS
338 FOUS30 KWBC 080035 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 835 PM EDT Sun Jul 7 2024 Day 1 Valid 01Z Mon Jul 08 2024 - 12Z Mon Jul 08 2024 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF COASTAL TEXAS... 01Z Update... ...TC Beryl for Coastal Texas into Louisiana... Beryl still has a landfall forecast prior to 12Z Monday on the middle TX Coast (please see the NHC website for the latest information) with the outer bands already pushing onshore early this evening. Initially dry air is wrapping into the system but this is expected to diminish later tonight and as the eyewall moves onshore, the threat of flash flooding will increase quickly. Not a lot of change was needed to the Day 1 ERO (through 12Z Monday) with only minor tweaks to the western side of the risk areas to tighten up the gradient some as the track guidance is clustering really well and there is evidence of a tighter western gradient to the precipitation at least tonight. The Moderate Risk remains in place for the potential for considerable urban and flash flooding. In terms of rainfall potential, the latest guidance, including 18Z HREF, suggests narrow/localized totals near the center/landfall between 6-7" likely (HREF mean) with some potential for locally higher amounts around portions of Matagord, Brazoria, and Fort Ben counties. ...Southern Plains to the central High Plains and to the Upper Midwest... Along a frontal boundary and as a shortwave trough digs across the region, late afternoon convection has fired up across the Front Range of CO and is slowly moving east/southeast. Initially nearly stationary storms will pose a flash flood risk for the potential for intense rain rates above 1"/hr and the latest guidance is keying on this activity congealing/organizing into several line segments as it moves south/east. Localized 2-3" totals through tonight will be possible and some of this could cause isolated to scattered instances of flash flooding. Down into the Texas Panhandle and Oklahoma, convection already developing along the warm front will slowly train/repeat over similar areas into tonight. Localized higher end rainfall amounts of 2-4" will be possible, most likely over south-central OK for the potential of scattered flash flooding. Farther north, greater synoptic forcing is present with the upper trough extending from an upper low over northern MN to the southwest over the central Dakotas and extending to the central High Plains. A few areas of organized convection early this evening will continue pressing east/northeast across Iowa, southeast MN, and western WI as well as a secondary area over eastern MO. Some of this activity will wane/diminish after peak heating and instability erodes, but a lingering threat into the night will persist and could pose an isolated flash flood risk. The latest HRRR runs show some redevelopment overnight across central MO that could repeat over some areas and bring some locally higher rainfall amounts. ...Southeast... The stalled frontal boundary and very moist airmass in place will continue to bring slower moving thunderstorms capable of producing very intense rain rates over the next several hours (late evening), particularly for portions of eastern GA and central SC. See the latest WPC Mesoscale Precipitation Discussion 585 for more details on this heavy rainfall threat tonight. Taylor Day 2 Valid 12Z Mon Jul 08 2024 - 12Z Tue Jul 09 2024 ...THERE IS A MODERATE RISK FOR EXCESSIVE RAINFALL FOR MOST OF EASTERN TEXAS... 21Z Update... ...East Texas through Arkansas... 12Z HREF consensus along with the 18Z HRRR feature feature a considerable swath of heavy rain ahead and east of the Beryl track which starts from just inland from the Middle TX coast at 12Z Mon. An areal average of 3-8" is featured from the upper TX Coast (from inflow bands right of the track) and in the inner core rainfall north from Houston-Bryan TX then into southwest AR and far southeast OK. The Moderate Risk is expanded a bit more northeast through the rest of TX as well as farther east toward the LA border for the inflow bands right of the track. At least locally considerable impacts can be expected. Fortunately this is a fairly progressive system per NHC forecast forward speed of at least 10kt. Given increased confidence in the heavy rain swath extending through western/central AR and far eastern OK warrants expansion of the Slight Risk up to the MO/AR border. A trend in the track to the right continues and will need to be monitored in future outlooks, especially considering how much inflow into the Ozark terrain/topographical enhancement will occur. Elsewhere, tropical moisture from Beryl into a cold frontal boundary draped over the southern Plains should focus scattered heavy rainfall over much of OK into the TX Panhandle where a Marginal Risk is maintained/expanded into northwest TX. ...Southeast... Convection in proximity to the lingering frontal boundary within PW anomalies of 2 to 3 sigma will persist over the southern Appalachians, much of GA, southern SC and northeast FL where a Marginal Risk is maintained. Recent rains have increased soil saturation levels, so this additional activity allows a threat for isolated flash flooding. Jackson Day 3 Valid 12Z Tue Jul 09 2024 - 12Z Wed Jul 10 2024 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS THE MIDDLE MISSISSIPPI VALLEY... ...Mid-South through Midwest... Beryl is expected to quickly phase with an upper trough as it lifts northeast from Arkansas Tuesday. A swath of heavy rainfall is expected to persist through this extratropical transition with the 12Z GFS/ECMWF in good agreement with another shift to the right with the track which is in line with NHC forecasts. 3-6 inches over southeast MO, south-central IL to central IN (along with an additional 1.5" or so over northern AR) warrants a Slight Risk that includes the St. Louis metro. Increased confidence in central Gulf coast precip, but limited inflow banding between the coast and the remnants over the Mid-South warrants trimming the Marginal Risk on the south side, while the more progressive and right trend in the track warrants bringing the Marginal Risk into western OH. ...Southwest... Monsoonal moisture feeds over eastern AZ through the southern Rockies warranting maintenance of the Marginal Risk for most of New Mexico, southeast Arizona into southern Colorado with particularly considerations for burn scars and areas that have seen ample rainfall recently. ...Southeast... Maintained the Marginal Risk over southern Georgia through the northern FL Peninsula given the abundant moisture over the region and diurnal forcing for locally heavy rainfall, especially for northeast Florida. General consensus of 12Z guidance continues to suggest 1 to 2 inches with local maximums of 3 to 4+ inches. ...Northeast... Some moisture from the Southeast and ahead of Beryl interacts with a front over the Northeast. Guidance is rather light with activity mainly in New England, so for now the Marginal Risk was trimmed back to north of NYC. Jackson Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt