Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Feb 05 2023 20:23:32 FOUS30 KWBC 052023 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 322 PM EST Sun Feb 05 2023 Day 1 Valid 16Z 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... There could still be local downpours over the highly urbanized corridor of southeast Florida northward toward the Space Coast through approximately 21Z today as moist easterly flow interacts with low pressure forming along a quasi-stationary surface boundary and weak low- to mid-level shortwave energy. Numerous showers will be drawn northward in association with the moisture pool...which was where the latest hi-res guidance and 12Z HREF suggested some potential for localized 2-3" totals along the immediate coast. In addition to showers associated with the low pressure area moving northward...there could be some more convection during the afternoon in a region of confluent flow along/ahead of a cold front farther south. Any of these instances could lead to localized runoff issues or short-term ponding in areas of poor drainage before the focus shifts off-shore. Bann Day 2 Valid 12Z Mon Feb 06 2023 - 12Z Tue Feb 07 2023 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Bann Day 3 Valid 12Z Tue Feb 07 2023 - 12Z Wed Feb 08 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 while a downstream jet streak over the Ohio Valley strengthens to near 130 kt by late Tuesday/early Wednesday...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 northeast Texas into northern Arkansas and far southern Missouri. 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 12Z runs of the ECENS and GEFS members still show decent probabilities for 2"+ totals over the period (with some potential for isolated 3-4 inch amounts) although there was a shift towards the north and northeast of their overnight runs. As a result...the Slight Risk area was expanded and shifted that way in this cycle. Did not want to remove too much from the southern end of the previous position, though, due to the above normal soil moisture in parts of the area 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 potential for heavy rainfall over saturated soils, flash flooding will become a greater concern late Tuesday night through Wednesday across this region.=20 Bann Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!_Zbt8Ndwoh3WITGf78UOhbozU9lDVjo07DFZxQ1Jz3AT= UHU-6wRGlsENjqyHXCEol-WPcF-AZRxXg98B7wBbJNMFB0I$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!_Zbt8Ndwoh3WITGf78UOhbozU9lDVjo07DFZxQ1Jz3AT= UHU-6wRGlsENjqyHXCEol-WPcF-AZRxXg98B7wBb4QUlZkI$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!_Zbt8Ndwoh3WITGf78UOhbozU9lDVjo07DFZxQ1Jz3AT= UHU-6wRGlsENjqyHXCEol-WPcF-AZRxXg98B7wBbR_Ys5EA$=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) .