557 FXUS21 KWNC 161818 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT October 16 2026 SYNOPSIS: Later next week, mid-level low pressure aloft and at the surface is favored over the central and southeastern contiguous U.S. (CONUS). Although these features are forecast to weaken heading into week-2, there is a lingering risk of heavy precipitation over the Southern Plains, along with an increased risk of high winds over the lower Eastern Seaboard early in week-2. Towards the middle of week-2, the potential return of mid-level low pressure offshore of the West Coast supports an increased risk of heavy precipitation and other weather related hazards across the western CONUS, however model disagreement in regards to timing, coverage and strength of these risks precludes any corresponding hazards at this time. HAZARDS Slight risk of heavy precipitation for parts of the Southern Plains, Sat, Oct 24. Slight risk of high winds for portions of the Mid-Atlantic and the Southeast, Sat-Mon, Oct 24-26. DETAILED SUMMARY FOR MONDAY OCTOBER 19 - FRIDAY OCTOBER 23: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY OCTOBER 24 - FRIDAY OCTOBER 30: By late next week, dynamical model 500-hPa height forecasts from the ECENS and GEFS are in good agreement featuring an amplified ridge axis overspreading much of the Plains and Mississippi Valley, bookended by a pair of mean troughs with one located over the southwestern CONUS, and the other digging far south into Florida and the tropical Gulf and Caribbean. As the amplified ridge center progresses eastward across south-central Canada early in week-2, much of the anomalous troughing is favored to weaken, however, the accompanying mean surface low in the lee of Rockies, and another surface system situated offshore of the lower eastern Seaboard may bring a lingering risk of unsettled weather over these two parts of the country early in the period. Later in week-2, there are some ensemble indications of mid-level troughing to reload over the eastern Pacific, which could bring a renewed risk of heavy precipitation over parts of the western CONUS. Downstream, models generally maintain a positively tilted orientation of the ridge axis, allowing for a weakness in the height fields and cyclonic flow to persist across the southeastern CONUS, supportive of continued unsettled weather across the region. Across the Great Plains, both the GEFS and ECENS both highlight the mean surface low across the Central and Northern High Plains on day 8 (Oct 24). Although this surface low is expected to swiftly fill-in by day 9 (Oct 25), continued frontal forcing further south is expected to promote enhanced and possibly heavy precipitation across the Southern Plains. Based on continued support in both raw and calibrated Probabilistic Extreme Tools (PETs), a slight risk of heavy precipitation remains posted and valid through Oct 24 with its coverage slightly shifted westward where there are increased chances for 3-day amounts exceeding an inch relative to yesterday. Tied to the weakening of both the troughing aloft and the surface low, there is a lessened risk of heavy high elevation snow over the Interior West and gusty winds over the Central and Northern Plains. While the ECENS maintains some residual cyclonic flow over the Interior West, the GEFS and Canadian ensembles are more zonal and quicker to bring calmer and drier conditions by the outset of the outlook period, which is supported in the GEFS based Snow Water Equivalent (SWE) and wind PETs. Therefore, both the slight risk of heavy snow over the Rockies, and slight risk of high winds over the Plains are removed in the updated outlook. Downstream, an area of enhanced precipitation and elevated winds are favored associated with an area of surface low pressure over the western Atlantic with high pressure to the north over the Northeast next weekend. While any westward protrusion of a quasi-stalled frontal activity would bring enhanced precipitation into coastal portions of the lower Eastern Seaboard, the uncalibrated GEFS and ECENS maintain the heaviest daily precipitation amounts offshore early in week-2, precluding any corresponding precipitation hazard. Given the synoptic setup, however, there is the potential for strengthening surface pressure gradients and periods of elevated winds, which is supported by both the GEFS and ECENS PETs depicting increased chances for wind speeds exceeding the 85th percentile. Therefore a slight risk of high winds is posted for the lower Eastern Seaboard for Oct 24-26. Towards the middle of week-2, a reloading trough offshore of the West Coast is depicted in the ensembles, but the GEFS and ECENS differ in regards to the strength, shape, and development timing of this anomalous mid-level feature. In response to more Pacific flow, PETs show an uptick in signals in percentile space (at the 85th climatological threshold), with the GEFS focusing these signals over the lower Four Corners and the ECENS featuring a more expansive coverage into the West Coast, including support for 3-day amounts exceeding an inch over northern California. In light of these differences, drier signals in the uncalibrated tools, and general uncertainty at this lead, no hazards are issued but a heavy precipitation potential, as well as other weather related hazards associated with a reloading trough over the western CONUS will continue to be monitored in upcoming outlooks. Upstream of an anomalous ridge axis extending into the Yukon, southwesterly flow and a mean surface low favored to the north of the Aleutians supports above normal precipitation for much of the southern Mainland and the Southeast early in the period. Good agreement exists between the GEFS and ECENS PETs featuring increased chances for 3-day precipitation amounts and wind speeds exceeding the 85th percentile associated with this pattern, however actual amounts and wind speeds are not expected to reach hazard thresholds, resulting in no corresponding hazards at this time. FORECASTER: Nick Novella $$