Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Feb 05 2023 07:39:51 FOUS30 KWBC 050739 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 238 AM EST Sun Feb 05 2023 Day 1 Valid 12Z Sun Feb 05 2023 - 12Z Mon Feb 06 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ....Southeast Florida to Space Coast... A quasi-stationary front draped through the Bahamas has led to easterly to northeasterly flow across southeast Florida early this morning. A pool of deeper moisture characterized by precipitable water values exceeding 1.25" has been drawn toward the coastline where regional radar currently shows numerous showers. The moisture pool will be drawn northward today along an inverted trough where the latest hi-res guidance and 00Z HREF suggests potential for localized 2-3" totals along the immediate coast. If deeper instability were to develop, intense rain rates exceeding 1"/hr would be possible but it's likely the strongest cores will remain just offshore. Given the relatively dry conditions in place and the uncertainty in the deeper/stronger showers being onshore, an excessive rainfall outlook was drawn for the area. However, locally heavy downpours remain possible over the highly urbanized corridor of Southeast Florida northward toward the Space Coast which could lead to localized runoff issues through 18Z today. Taylor Day 2 Valid 12Z Sun Feb 05 2023 - 12Z Mon Feb 06 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Taylor Day 3 Valid 12Z Mon Feb 06 2023 - 12Z Tue Feb 07 2023 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE ARKLATEX REGION... Positively titled longwave trough ejecting out of the Four Corners region Tuesday begins to take on a neutral tilt as it approaches central Texas Wednesday while a downstream jet streak over the Ohio Valley strengthens to near 130 kt by early Wednesday both providing the large scale forcing for ascent across the Arklatex region. The deep layer southerly flow ahead of the system will bring northward higher moisture characterized by precipitable water values near 1.5", which is between 2-3 standard deviations above the climatological mean. Late Tuesday night into Wednesday morning the strengthening low-level jet (850 mb flow 30-40 kts) and deep layer lift is expected to produce several clusters of heavy rainfall initially across eastern Texas that then track across parts of northern Louisiana, southeast Oklahoma, and western Arkansas. The favorable overlap of greater lift, moisture, and instability (MUCAPE of 1000 J/kg) should produce intense rain rates exceeding 1-2"/hr at times and a deep layer flow near parallel to storm motions could allow for training/repeating rounds of heavy rainfall. The latest ECENS and GEFS members show decent probabilities for 2"+ totals over the period. Some potential for isolated 3-4" totals exists. Adding to the flash flood threat, much of the region has much above normal soil moisture conditions due to recent heavy precipitation. The latest NASA SPoRT 0-40 cm layer soil moisture percentiles are above 90-95 percent in places and precipitation departures are 300-600 percent of normal. Given the expected heavy rainfall setup over saturated soils, flash flooding will become a greater concern late Tuesday night through Wednesday across this region.=20 Taylor Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8q89DVM5yJMecWX3soMyNNvhgbSocxpQoWYpr48vHYea= 4ITWctXsfYztnLcoHAXtvBjnPqmYc23o4o7yJ6K1RyZxa9s$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8q89DVM5yJMecWX3soMyNNvhgbSocxpQoWYpr48vHYea= 4ITWctXsfYztnLcoHAXtvBjnPqmYc23o4o7yJ6K1lAGPKgQ$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8q89DVM5yJMecWX3soMyNNvhgbSocxpQoWYpr48vHYea= 4ITWctXsfYztnLcoHAXtvBjnPqmYc23o4o7yJ6K1X4mMWMY$=20 $$ =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .