FOUS30 KWBC 030102 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 802 PM EST Mon Nov 2 2026 Day 1 Valid 01Z Tue Nov 03 2026 - 12Z Tue Nov 03 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF CENTRAL AND SOUTHERN FLORIDA... ...Florida... We will maintain a Slight risk across much of central and southern FL, with the main focus continuing to be along the east coast of the state. Overall coverage and magnitude of heavy rainfall should generally be lower overnight than what we have been seeing, with overall synoptic forcing and high res model QPF on a downward trend. However, low level easterly flow will continue, and recent HRRR forecasts show a continuous influx of instability into the state through the overnight hours. So while convective coverage may decrease, the potential for localized extreme rainfall will continue given the instability, PWs and coastal convergence persisting. Overall it seems like the threat is greatest south of the areas hardest hit over the past 48 hours, but overall confidence on the details remains low. Model guidance has not been doing a great job with the mesoscale details, and thus observational trends will need to be relied upon for the overnight convective evolution. ...Plains... Localized flash flooding will be possible overnight from portions of TX into IA. Through the evening hours the risk may be maximized along a strong low level convergence axis from western KS into southern NE. Instability should erode fairly quickly here, and thus the risk should peak within the next couple hours. Thereafter the strongest convection should be from TX into MO. While some initial training is possible, the overall storm mode should be a progressive convective line. This should keep the flash flood threat isolated in nature and mainly confined to a rate driven urban risk, and thus we were able to remove the Slight risk with this update. Chenard Day 2 Valid 12Z Tue Nov 03 2026 - 12Z Wed Nov 04 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL PORTIONS OF MID- SOUTH... ...Lower and Mid-Mississippi Valley... 20Z Update: Only small modifications were necessary for the inherited SLGT risk across the Lower Mississippi Valley with the emphasis of flash flooding still within the zone between northern MS, southwestern TN, over into far northwest AL. The trend from guidance was to press the front a bit faster to the east leading to heavier precip axis located a bit downstream of where the previous QPF max was located. ML guidance is still highlighting the area back near the Mississippi with the max over the Mississippi Delta into southwestern TN. Secondary max showing up within the CAMs over southern AR, back towards the ArklaTex where the instability is the greatest and low-level convergence will be maximized in the afternoon hours during the maturing instability period. FFGs further southwest are running very high due to a prolonged drought in the region, so refrained from a SLGT risk expansion into this particular zone, but smaller towns across southern AR back towards Shreveport may see local flash flood prospects a bit higher compared to surrounding areas. FFG exceedance probs are still focused up near Memphis and northern MS into western TN with a potential for heavy rainfall back up to the west of Nashville. The SLGT risk was expanded a bit north of the previous issuance and bit east to account for the faster trend of the cold front advancement which correlates to heavier rainfall potential downstream. Kleebauer ..Previous Discussion.. The general consensus of the hi-res guidance shows that storms developing late Monday will remain ongoing along an advancing cold front extending from the mid Mississippi Valley back into eastern Texas Tuesday morning. There is some indication in the guidance that heavy rates and continued southwest-northeast training may elevate the threat for heavy amounts and flash flooding from the Ozark region into southeastern Missouri. This suggests an upgrade may need to be considered at some point, but for now maintained the outlook at just a Marginal Risk. Farther east, a Slight Risk centered over the Mid-South was maintained -- where deep moisture and favorable upper jet forcing are expected to support re-intensifying storms capable of producing heavy rainfall rates. The previous Slight Risk was largely maintained, but adjusted a little to reflect the REFS high neighborhood probabilities for 2-3+ inches across this area. Pereira ...Florida... 20Z Update: Mo changes to the previous forecast as the forecast remains on track from the last forecast issuance. The heavy totals the previous 24hrs will only add to the threat over the east- central FL coast as soil moisture will maintain well above normal state with the latest soil moisture percentiles already pushing above 90% for areas between Melbourne to Port St. Lucie/Stuart area. This will provide an enhanced prospect for flash flooding, even if the setup isn't as pronounced as previous periods. Heaviest rainfall within the latest 12z HREF/REFS means are a bit south compared to today's activity, so this may help limit future impacts as the best convective risk lies away from the hardest hit location. No matter the case, there is still at least an isolated threat for flash flooding with the prevailing easterly flow over the peninsula for Tuesday. Kleebauer ..Previous Discussion.. Easterly flow will weaken this period; however, with anomalous moisture remaining in place, cannot rule out additional localized heavy rainfall amounts resulting in at least isolated flash flooding concerns, especially in urbanized locations and areas previously inundated with heavy rains. Pereira Day 3 Valid 12Z Wed Nov 04 2026 - 12Z Thu Nov 05 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE TENNESSEE AND LOWER OH VALLEYS TO THE SOUTHERN AND CENTRAL APPALACHIANS... 20Z Update: Only minor changes to the previous MRGL risk with the main area of interest still aligned within the upslope area across the Southern Appalachians. A bit of an expansion of the MRGL risk over southern Ohio, as well, with some of the trends showing greater convective potential over the Central Appalachian area ahead of the cold front. Considering the more sensitive nature of the terrain in this area of the CONUS, opted to expand the risk to cover for the low-end threat. Totals generally 1-2" in the most impacted areas, but global ensembles indicate some risk of 2-3" in isolated areas which could very much cause some flash flood concerns in the region of interest. Will assess in the coming days with the additional forecasts from the CAMs, but antecedent dryness will likely curb any widespread flash flood threat, unless magnitudes increase in the coming days. Kleebauer ..Previous Discussion.. Activity developing late Tuesday may continue into the early part of the period, with a ribbon of deep moisture and favorable upper jet forcing contributing to additional heavy rates and possible flash flooding across parts of the Tennessee and lower Ohio valley early on. Storms are forecast to shift east into the central and southern Appalachians later in the day, where orographic effects may help bolster totals across parts of the region and raise flash flooding concerns, especially in the more sensitive parts of the central Appalachians. Pereira Day 4 and Day 5 Valid 12Z Thu Nov 05 2026 - 12Z Sat Nov 07 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Enough model spread remains to withhold adding any Marginal risk to the Mid-Atlantic and Northeast. Still looks like the front will stall near the coast and allow for an axis of heavier rainfall amounts. A solution such as the 12z ECMWF would probably result in at least a localized flash flood risk from the eastern Mid- Atlantic into southern New England, with 2-3" of rain and ~500 J/kg of CAPE allowing for some embedded higher rainfall rates. However, other models are further east with this axis (mainly offshore), and the degree of instability is also uncertain. Given the dry antecedent conditions we will hold off on adding a risk area until we have more confidence in an onshore rainfall axis and some overlapping instability. Chenard 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 $$