• Hazards: Damaging winds, flash flooding
  • Threat Level: Marginal (Level 1/5)

Summary/Discussion: Expect a summer-like thunderstorm pattern to develop this afternoon. The enviornment is suitable for a few stronger thunderstoems will will have the possibility for damaging winds – and – given the heavy rainfall probability, instances of flooding will certainly be possible.

HUN CWA Outlook (North Alabama)
Alabama Overview Outlook
BMX CWA Outlook (Central Alabama)

Technical Discussions

...Lower MS Valley/Mid-South...
   An MCV near the OK/AR border, that emanated out of a decaying MCS,
   should move east today overtaking/merging with a nearly stationary
   MCV in southeast AR. A confined belt of enhanced low/mid-level
   southwesterlies should be present this afternoon. However,
   destabilization will likely be more pronounced well south/southwest
   of the MCV track given how far south the large-scale convective
   outflow has surged in eastern TX and the Ark-La-Tex, in addition to
   weak mid-level lapse rates to the east. Still, have added a low
   tornado probability given the conditional risk. Otherwise, isolated
   damaging winds should be the main threat. 

...Southern Plains into the Lower Mississippi Valley...
Two distinct precipitation events will likely occur across the 
region through Tuesday morning, bisecting the expanded Slight Risk 
area. The first area of interest is related to the decaying MCS 
moving across southern OK/northern TX early this morning.  The 
second area of concern is with respect to the MCV situated over 
central AR.  Both of these area of ongoing convection will set the 
stage for convective development through the remainder of the 
forecaster period. 

A sharpening upper trough will pivot through the northern Plains 
into the Midwest/Great Lakes region.  At the surface, a low will 
be migrating northeast from IA into MI with a cold front draped 
southwest into eastern KS, OK and across northern TX.  Another 
shortwave moving through the central Rockies will emerge into the 
central/southern Plains late this afternoon, moving atop of the 
front and other residual boundaries left over from this mornings 
convection. This is one area of concern. Uncertainty remains with 
respect to where the front will be located, but also where the 
residual outflow boundaries will be positioned.  This will play a 
role in where convection develops later in the evening and through 
the overnight hours.  Model guidance varies on the evolution of 
convection; some solutions show little development (NMMB/HRRR), 
others show widespread convection across southeastern 
OK/northeastern TX (GEM/00Z HRRR) and one model illustrates 
multiple MCSs diving through TX (ARW).  Regardless, the 
pre-frontal environment will be supportive of convective 
development if sufficient lift is present.  MUCape climbing 
towards 3000 J/kg will provide sufficient instability for intense 
rainfall rates, especially when combined with precipitable water 
values of 1.75-2" surging northward aided by 20-30 knot low level 
flow from the Gulf of Mexico. Based on model continuity and 
ensemble support, it appears the best location for overnight 
development, thanks to the strengthening low level jet position, 
would be across northeastern TX/southeastern OK. However, again, 
this is highly dependent on the boundary/front positions and the 
mid-level shortwave. Areal average precipitation should be around 
1-2+ inches with locally higher amounts expected.  Rain rates 
could approach 2 inches/hour, though expect rates to generally 
stay below 1.5 inches/hour.  Given this area has been worked over 
from numerous convective systems over the past several days, FFG 
is a bit lower in some locations.  Therefore, this region is 
sensitive to additional heavy rainfall.  While confidence is below 
average on convective development later tonight, enough model 
signal was present over saturated soils to expanded the Slight 
Risk area a bit farther west and south.  

The other area of concern is across portions of AR into far 
northwestern MS as the MCV decays through morning with the energy 
shifting east. Uncertainty also exists with regard to the 
trajectory for the energy which will certainty influence 
downstream convection during the afternoon.  The axis of heavy 
rain may need to be lifted farther north or perhaps won't develop 
at all if blow-off cloud debris inhibits destabilization.  Again, 
models are at odds with the evolution of afternoon activity.  So 
the Slight Risk across AR accounts for the ongoing/decaying MCV 
and the expected convection farther east into northwestern MS that 
may fall over lower FFG.