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   QPFERD   
      
   Excessive Rainfall Discussion   
   NWS Weather Prediction Center College Park MD   
   752 PM EST Thu Jan 8 2026   
      
   Day 1   
   Valid 01Z Fri Jan 09 2026 - 12Z Fri Jan 09 2026   
      
   ...THERE ARE MARGINAL RISKS FOR EXCESSIVE RAINFALL ACROSS PORTIONS   
   OF THE MIDWEST & LOWER MISSISSIPPI VALLEY...   
      
   ...0100 UTC Update...   
   Two relatively targeted Marginal Risk areas (parts of the Midwest=20   
   and Lower MS Valley) remain generally on track for the overnight=20   
   hours. Both are considered 'low-end' Marginals, i.e. with the 40km=20   
   neighborhood probability of rainfall exceeding 1 or 3 hourly FFG is   
   closer to 5% than 15%. Deep-layer instability (or lack thereof),=20   
   even elevated, is the main inhibitor to flash flooding across the=20   
   Midwest Marginal Risk area, although some snowmelt and otherwise=20   
   low FFG values would offset somewhat. Farther south near the Gulf=20   
   Coast, there at least 250-500 J/Kg of MUCAPE would be available,=20   
   perhaps closer to 1000 J/Kg closer to the Gulf Coast. However, as=20   
   is the typical tradeoff this time of year, the soils farther south=20   
   (no snow cover nor frost depth) can absorb quite a bit more=20   
   rainfall before any runoff is generated.=20   
      
   Hurley   
      
   Day 2   
   Valid 12Z Fri Jan 09 2026 - 12Z Sat Jan 10 2026   
      
   ..THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF   
   THE TENNESSEE VALLEY AND DEEP SOUTH...   
      
   20Z Update...   
   Following the general trend of the 12Z guidance, the outlook areas   
   extending from the lower Mississippi Valley to the southern   
   Appalachians were shifted a little south and east. A Slight Risk   
   was maintained from southeastern Louisiana to the southern   
   Appalachians, where neighborhood probabilities from the 12Z HREF   
   for amounts above 2 inches are 50 percent or greater. Within this   
   area, the HREF suggests the heaviest totals are most likely to   
   center from southeastern Louisiana to central Alabama, where high   
   (greater than 70 percent) probabilities for amounts over 3 inches,   
   and some 30-60 percent probabilities for amounts greater than 5   
   inches, are indicated.   
      
   Pereira   
      
   Previous Discussion...   
   ...Lower Mississippi Valley/Southern Appalachians...   
   A positively tilted trough with minimal eastward progression due   
   to the parent cyclone's progression northeast will generate a broad   
   axis of ascent from the Mississippi Valley to points eastward with   
   a cold frontal progression slowly migrating east. An anomalously   
   moisture plume ahead of the trough, noteworthy for January and near   
   summer averages with a range of 1.50-1.75", will be accompanied by   
   500-1500 J/kg of MU CAPE. Ample shear for convective organization   
   is expected, with low- level convergence more or less fixed from   
   the Atchafalya Basin in LA into the southern Appalachians. The   
   guidance is wet, with local 4-7" totals forecast locally. The   
   guidance has shifted southwest,. which caused a southwest shift in   
   the risk areas.   
      
   This synoptic setup is classic for a flash flood prospect across   
   this region. Deep layer southwest flow should lead to cell   
   training, and enough effective bulk shear exists for mesocyclone   
   formation. Hourly rain amounts up to 2.5" are possible here, which   
   would overwhelm urban environments. The 00z HREF for the first half   
   of the period advertised a 30-35% of 5"+ near Laurel MS, which if   
   it occurred within a few hours would overwhelm non-urban   
   environments as well. At the moment, this appears to be a high end   
   Slight Risk, but it wouldn't be surprising if a Moderate Risk   
   was considered as we get further inside the mesoscale guidance   
   window. The eastern bounds of the Marginal Risk area were   
   coordinated with the RNK/Blacksburg VA, GSP/Greer SC, and   
   FFC/Peachtree City GA forecast offices.   
      
   Roth   
      
      
   Day 3   
   Valid 12Z Sat Jan 10 2026 - 12Z Sun Jan 11 2026   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS   
   OF THE SOUTHERN APPALACHIANS...   
      
   20Z Update...   
   No significant changes were made to the Marginal Risk area   
   centered over the southern Appalachians.   
      
   Pereira   
      
   Previous Discussion...   
   Heavy rainfall early in the period is expected over what should be   
   at least partially saturated ground across portions of the   
   Southern Appalachians before heavy rainfall ejects into the   
   southern Mid- Atlantic States. Added a Marginal Risk as a   
   precaution for this reason; the threat not expected to persist past   
   18z Saturday.   
      
   Roth   
      
      
   Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/94epoints.txt__;!!DZ3fjg!6m6txmeB6trfgANzDYnfKBKlu3t_93bhJ7ZFtLPB78KW=   
   Wa7wB0K_JYy4Y0DD1t-drhFHwvbpzoUoyI-LaD4-9Lvx5EA$=20   
   Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/98epoints.txt__;!!DZ3fjg!6m6txmeB6trfgANzDYnfKBKlu3t_93bhJ7ZFtLPB78KW=   
   Wa7wB0K_JYy4Y0DD1t-drhFHwvbpzoUoyI-LaD4-0B4ImAk$=20   
   Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/99epoints.txt__;!!DZ3fjg!6m6txmeB6trfgANzDYnfKBKlu3t_93bhJ7ZFtLPB78KW=   
   Wa7wB0K_JYy4Y0DD1t-drhFHwvbpzoUoyI-LaD4-kMCRM1Y$=20   
      
   =3D =3D =3D   
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