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   FOUS30 KWBC 222321   
   QPFERD   
      
   Excessive Rainfall Discussion   
   NWS Weather Prediction Center College Park MD   
   621 PM EST Sat Nov 22 2025   
      
   Day 1   
   Valid 01Z Sun Nov 23 2025 - 12Z Sun Nov 23 2025   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS   
   OF SOUTHEAST ARIZONA INTO CENTRAL ARIZONA...   
      
   Infrared satellite imagery shows cooling cloud tops in association   
   with showers and thunderstorms across central and southeast AZ=20   
   within a region of 700 hPa confluence ahead of a progressive deep=20   
   layer low, with some recent uptick in coverage.  Pockets of 500+=20   
   J/kg of MU CAPE exist across west- central and southeast AZ per SPC   
   mesoanalyses, with instability increasing due to cooling aloft and   
   some degree of daytime heating/sunshine, particularly across=20   
   southeast AZ. Effective bulk shear of 30-50 kts exists here, which=20   
   is leading to an environment with both organized and ordinary=20   
   convective cells, with the organized activity edging east of due=20   
   north while the less organized storms move just west of due north.=20   
   Precipitable water values of 0.5-1" lie here. The atmosphere is=20   
   cool, with 1000-500 hPa thickness values of 5550-5600 meters. When=20   
   combined with the available moisture, the column is approaching=20   
   saturation.   
      
   The mesoscale guidance implies increasing convective coverage and   
   an increasing incidence of 0.5"+ an hour amounts over the next   
   several hours, with the 12z REFS and 18z HREF guidance suggesting   
   the heaviest rainfall in the 01-05z time frame before fading   
   thereafter. This could be due to cell training, occasional=20   
   mesocyclone formation, or cell mergers between more and less=20   
   organized convective activity. As the upper level system continues=20   
   marching northeast, winds should veer somewhat which should allow=20   
   convection to shift somewhat to the east with time, with activity=20   
   shifting increasingly into mountainous areas. With hourly amounts=20   
   to 1" and local totals to 2" possible, the incidence of impactful=20   
   heavy rain is expected to be isolated to widely scattered, mainly=20   
   within arroyos/dry washes, box canyons, and any area burn scars.   
      
   Roth   
      
      
   Day 2   
   Valid 12Z Sun Nov 23 2025 - 12Z Mon Nov 24 2025   
      
   ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF CENTRAL   
   AND NORTHERN TEXAS INTO PORTIONS OF SOUTHERN OKLAHOMA...   
      
   ...20z Update...   
      
   Consensus QPF guidance has continued to focus on the western side   
   of the inherited Slight Risk, making the primary adjustment with   
   this update to shift both the MRGL and SLGT areas a bit west. The   
   upper-level system driving the expected rainfall (which is expected   
   mostly after 00z on Mon) continues to look less amplified and cut-   
   off, placing the area of concern closer to the base of the trough   
   and tilted the QPF axis a bit more west-to-east than previously.   
   While this may increase the risk locally for training convection,   
   the main axis is also now more solidly north of the bulk of the   
   Hill Country (particularly where heavy rainfall occurred earlier   
   this week) into much of the Big Country/Northwest TX. While the   
   rainfall axis still impinges on western portions of the Dallas-   
   Fort Worth metro, the best probabilities for 3" exceedance are   
   concentrated to the west of the populous areas (as well as north   
   of San Angelo proper). While this less populated region of Central/   
   Northwest TX within the south-central portion of the updated SLGT   
   risk has indications of 5"+ potential (per 40-km HREF 5" exceedance   
   probs of ~15%), this signal is being driven seemingly entirely by   
   one member (the FV3, which is generally one of the less reliable   
   members) with the bulk of the CAM guidance in good agreement   
   indicating 2-4" totals. Given that much of this QPF is also   
   expected in the last 6 hour period of the forecast, there is still   
   plenty of time to see if this FV3 run is an outlier or if more CAM   
   guidance comes into alignment with this heavier solution. This may   
   necessitate a future targeted upgrade to Moderate Risk (which is   
   also possible for San Angelo and/or the DFW metro areas, should the   
   QPF axis shift a bit south and/or east).   
      
   Churchill   
      
      
   ...Previous Discussion...   
      
   The latest guidance continues to depict a southwest-northeast   
   orientated axis of heavy rain panning from the northern part of the   
   Hill Country to northeast Texas. General consensus suggests 1 to 3   
   inches however, the ECMWF is persistent on the higher end with   
   amounts 3 to 5+ inches and placed further south/southwest than   
   other solutions. This is somewhat concerning, as this brings the   
   forecast axis of QPF even more into alignment with areas that   
   realized heavy rainfall in prior days.   
      
   A Slight Risk remains in effect and seems appropriate given at   
   least three days of recovery from the previous heavy rainfall   
   event and uncertainty with regard to the amount of training and   
   resultant QPF.   
      
   Campbell/Churchill   
      
      
   Day 3   
   Valid 12Z Mon Nov 24 2025 - 12Z Tue Nov 25 2025   
      
   ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR MUCH OF   
   ARKANSAS AND NORTH TEXAS INTO ADJACENT PORTIONS OF SOUTHEASTERN   
   OKLAHOMA, NORTHERN LOUISIANA, AND NORTHWEST MISSISSIPPI...   
      
   ...20z Update...   
      
   Organized convection is expected to be ongoing Monday morning   
   across a good portion of North TX and into southeastern OK and the   
   Ark-La-Tex, moving east across Arkansas and into the Mid-South   
   during the day. Confidence is highest in robust convection in the   
   vicinity of North TX early in the period, whereas solutions diverge   
   somewhat later in the day...with one camp of guidance suggesting   
   training convection and localized totals as high as 3-5" from a   
   relatively hydrologically sensitive region from southwest OK into   
   northwest/north-central AR (mainly driven by the GFS/GEFS) and the   
   other camp indicating higher odds for 3" exceedance farther south   
   into the Ark-La-Tex and southern AR (led by the ECMWF/ECENS, but   
   also having greater support from the CMC suite and UKMET as well).   
   Overall this led relatively to little change to the inherited SLGT   
   risk, mainly shifting the area a bit west and flattening it out to   
   account for the (aforementioned) less amplified upper-level trough.   
   There may need to be considerations for a future targeted Moderate   
   risk upgrade, though for this to occur more guidance would most   
   likely need to shift towards the northern solution (or consolidate   
   towards the southern solution while also getting wetter, as FFGs   
   indicate much less sensitive soils that would require a broader   
   area of 3"+ before meeting Moderate coverage criteria).   
      
   Churchill   
      
      
   ...Previous Discussion...   
      
   The broad area of showers and thunderstorms are expected to shift   
   to the eastern portion of the Southern Plains and the Lower   
   Mississippi Valley. The highest amounts are expected to focus over   
   the AK-LA-TX region. While areal averages of 1 to 3 inches are   
   forecast, isolated maximums of 4+ inches will be possible. There   
   will be some overlap of heavy rainfall from the previous day which   
   will lower local FFGs. Training and back building of storms may be   
   possible, particularly for norther Texas and Arkansas. A Slight   
   Risk is in effect from northeast Texas/northern Louisiana to   
   western Tennessee/northwest Mississippi.   
      
   Campbell   
      
      
   Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/94epoints.txt__;!!DZ3fjg!4OPVVVAF3thHT42bUb8rYNzogVkWFfmDt6HZz7r5SMi2=   
   RxG2Rvjr29jkuy4zrugnghbEf0KYzK2cMoeNTDQQwwABDnA$=20   
   Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/98epoints.txt__;!!DZ3fjg!4OPVVVAF3thHT42bUb8rYNzogVkWFfmDt6HZz7r5SMi2=   
   RxG2Rvjr29jkuy4zrugnghbEf0KYzK2cMoeNTDQQu97NlBs$=20   
   Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/99epoints.txt__;!!DZ3fjg!4OPVVVAF3thHT42bUb8rYNzogVkWFfmDt6HZz7r5SMi2=   
   RxG2Rvjr29jkuy4zrugnghbEf0KYzK2cMoeNTDQQucwzIFA$=20   
      
   =3D =3D =3D   
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