Extended Forecast Discussion NWS Weather Prediction Center College Park MD 226 AM EDT Sun Oct 6 2024 Valid 12Z Wed Oct 09 2024 - 12Z Sun Oct 13 2024 ...Milton could bring potentially catastrophic impacts across parts of Florida through Wednesday... ...Overview... Tropical Storm Milton, currently located in the western Gulf of Mexico and is forecast to continue to track east-northeast across the Gulf while strengthening to possibly major hurricane strength. Milton should be approaching the west coast of the Florida Peninsula by early Wednesday with significant rainfall/flooding, high wind, and storm surge threats. Elsewhere, an upper trough (anchored by an upper low that may track over or near New England) will move through the East mid next week as an upper ridge upstream tracks from the West to Central U.S. bringing a period of climatologically warm weather. By later next week, a Pacific trough will push inland over the West with some generally light precipitation to accompany. ...Guidance/Predictability Assessment... Model guidance continues to suggest Milton will strengthen into a possibly major hurricane as it tracks east across the Gulf. There remain some north-south wobbles and uncertainty in the timing, with plenty of run to run variability. The CMC remains the slowest of the deterministic models, with the UKMET on the faster side. The GFS and ECMWF are a good middle ground solution and are closest to the official track from the NHC. Timing variability also evident in the latest runs of the AI/ML models as well. Milton may transition to extratropical quite quickly after it crosses the Florida Peninsula into Thursday. Farther north with the main jet stream, models are reasonably agreeable with the pattern described above. The Pacific trough shows the most spread especially with regards to timing, but some weekend uncertainty regarding cut off energy meandering over the Southwest. Prefer a blend of the ensemble means with the ECMWF for this feature. ...Weather/Hazards Highlights... Milton is forecast to be a major hurricane as it approaches the West Coast of Florida by the start of the period on Wednesday. There is an increasing risk of life- threatening storm surge and wind impacts for portions of the west coast of the Florida Peninsula beginning even before Wednesday. Residents in these areas should ensure they have their hurricane plan in place, follow any advice given by local officials, and check back for updates to the forecast. 6 to 12 inches of rainfall is not out of the question for parts of the FL peninsula, but where that exact axis of heavy rainfall sets up, is still quite uncertain and entirely dependent on the exact track Milton takes across FL. Regardless, significant rainfall and impacts are expected to accompany Milton, and the Day 4 ERO period (Wednesday) now shows a moderate risk for flash flooding across the north- central portion of the Peninsula, including the major population regions of Tampa Bay, Orlando, and Jacksonville. By Thursday, the heaviest rainfall associated with Milton should be offshore of FL, but did continue a marginal risk for northeast FL to account for possibly slower speed. Elsewhere, the upper low over/near New England should allow for some lake-enhanced rain within in westerly flow across the Great Lakes. A mean frontal zone with one or more embedded waves should reach near the northern Pacific Northwest by early-mid week, producing some periods of light to locally moderate rain and non- zero chances of snow in the highest elevations. Widely scattered showers are possible at times across the Four Corners states into parts of the south-central U.S., but anything beyond light rain is unlikely. The strong and persistent western-central U.S. upper ridge will promote an extended period of well above normal temperatures over that part of the country. Gradual eastward drift of the ridge axis will shift the highest anomalies into the north central Plains by Wednesday, and some locations could reach 20-30F above normal persisting into late week. Meanwhile height falls slowly pushing in over the West Coast will support a trend toward near normal temperatures by Wednesday or Thursday. Temperatures over most of the East should be cooler as upper troughing sets up near the East Coast, trending back to normal next weekend. Frost/Freeze may be a concern across portions of the Upper Great Lakes region and interior Northeast mid week before the upper low scoots out of the region. Santorelli 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