Two weather phenomenons in two different sections of the state? Two modes of different type of weather, which indicates...Definition of bi (two)..So two modes indicates bi-modal.
TOPICS TO BE DISCUSSED IN DETAIL...
2 HAZARDS ANTICIPATED...
1. Winter Weather Possible in the Northern Two Row of Counties on Friday Night
2. Accumulations Anticipated to Minimal if any
3. Wind chills in the teens-mid 20s by Saturday Morning..Coldest north
4. Severe Weather Threat Possible Southern AR between 5 PM and Midnight. Timing subject to change
5. Damaging Winds and Hail Primary Concerns, however tornado or two is possible??
Confidence....Moderate in Both
WINTER WEATHER THREAT... WINTER MIX OF FREEZING RAIN, SLEET, SNOW FOR FAR NORTHERN ARKANSAS ON FRIDAY EVENING...VERY LIGHT ACCUMULATIONS IF ANY ANTICIPATED. WINDY CONDITIONS, FALLING TEMPS, AND WIND CHILLS.
Given the favorable track of the low pressure, along with shallow air spilling south. The low pressure will act to pull in colder temps at the surface and aloft Friday Night across far Northern AR, and this will support the potential of wintry mix in the form of sleet/snow, and maybe a brief period of freezing rain on Friday Night. Given the below average temperatures in March and into April across the northern AR with soil temps in the 40s.
IF enough moisture overruns the colder air, some light accumulation is possible, but most will not see much of any impacts. It will be a sight to see for our northern counties though for it being April. Accumulations are anticipated across parts of Southern/Central MO where better colder air and moisture will reside. The breezy northerly winds behind the cold front will suggest wind chills in the teens across Northern AR by Saturday Morning.
SEVER WEATHER THREAT... LOCALLY HEAVY RAINFALL TRHREAT..QUICK 2+ INCHES IN A SHORT-PERIOD OF TIME POSSOBLE
DAMAGING WINDS, LARGE HAIL, AND A TORNADO OR TWO POSSIBLE ACROSS SOUTHERN AR DURING THE AFTERNOON AND EVENING HOURS...DETAILS BELOW
The atmospheric conditions are stable currently, however that will change as we head into Thursday Evening as warm-air pushes northward with instability increasing aloft. This will be ahead of the warm-front therefore isolated to widely scattered showers and thunderstorms are possible in Southern ½ AR on Friday Morning, and as we head into the day the warm-front will continue to push northward towards Central/Northern Arkansas.
This will increase the surface dew-points and surface temperatures across the Southern half of the state. A strong cold front with shallow air-mass is expected to push into the state on Friday, and these fronts tend to hang up in the Ouachita mountains and Ozarks, and while it is not expected to stall *the more significant push of arctic air is anticipated to be locked up further north*. This will suggest the possibility of activity developing along and ahead of the cold front instead of activity behind the cold front.
The environmental conditions based on a consensus of model guidance and the setup suggest conditions to become increasingly unstable along with increasing wind shear/vertical shear across Southern ½ of AR and especially Southwest and South-Central Arkansas.
The short-term/higher-res models are showing stronger surface low development which is a bit concerning as this will likely erode the cap across the region. This will support possible cellular development ahead of the cold front, therefore a linear and isolated cellular development is possible. Conditions will be supportive of damaging winds, large hail, and perhaps a tornado or two within the stronger storms during the evening hours. Time-frame will be determined as we get closer to the event, but it appears this be around sunset and after.
***However, there is the possibility that the cold front will outrun the storms, and this become quickly linear with a more limited threat of severe weather which will need to be watched closely over the next coming days***Even if the background environment is favorable for storms initially. The cold front could play as the limiting factor if the cold front outruns the line of storms, and if the cap doesn’t erode and conditions do not become as unstable as predicted to rain in the morning and extensive cloud cover.
So several scenarios are possible regarding the storm threat. Stay tuned to later updates.