Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 PM EST Wed Nov 15 2023 Valid 00Z Thu Nov 16 2023 - 00Z Sat Nov 18 2023 ...Heavy rainfall and significant urban flash flooding will be a major concern tonight for southeast Florida... ...Locally heavy snowfall expected tonight across portions of the Northern Rockies... ...Unsettled weather remains in the forecast across much of California... ...Dry and mild conditions will continue across the Intermountain West, Plains, and Midwest while gradually expanding toward the Mid-Atlantic and Northeast over the next couple of days... Heavy rainfall and thunderstorms will pick up over southeast Florida tonight along a quasi-stationary front. An area of surface low pressure may develop along the stationary front just south of the Miami metro area, which would enhance any convection that initiates. The heaviest rainfall is expected overnight between 7pm and 1am. This is when rainfall rates between 2-3"/hr are expected and the greatest Flash Flood threat is likely. A Moderate Risk (at least 40% chance) of Excessive Rainfall leading to Flash Flooding is in effect for much of the southeast Florida coast from Key Largo up to West Palm Beach. High rainfall rates over this urbanized corridor will potentially make this a highly impactful and especially dangerous flash flood situation. There is a high (80-90%) chance of 5" totals and a moderate to high (50-80%) chance of 8" totals with potential for localized totals nearing 10" by Thursday morning. If roads look flooded then "turn around, don't drown!" Heavy rainfall should begin to subside by day-break Thursday morning. An upper level trough swinging through Canada and the Northern/Central Rockies will produce heavy mountain snow and some lower elevation rain showers to the Northern Rockies tonight before spreading snowfall into the Central Rockies on Thursday. A deep upper level low stationed off the coast of California will continue to generate scattered showers and thunderstorms and snow for the Sierra over the next couple of days. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php