NORTHWEST ARKANSAS (KNWA) — Lots to unpack in the forecast this morning. Winds and fire. Weather concerns come first on Wednesday, followed by strong/severe storm and heavy rain potential Thursday night into Friday, and to put icing on the cake winter weather potential Friday night and Saturday.
The near term remains quiet in a nw flow pattern aloft over the plains. Low level thermal fields warm thru the day and suggest that another warm and pleasant day is in store with not much wind.
South winds crank up on Wednesday over the plains as heights fall over the western conus and lee side surface low pressure develops over eastern co. tight pressure gradient and strong winds off the deck suggest winds will be quite gusty during the afternoon and possibly even into the overnight Wednesday night. The air will still be relatively dry as low level moisture will take time to get back up here. It is the first day of strong south winds that is usually the worst as far as fire weather is concerned. The winds, relatively dry air and well above average temps will yield elevated to significant fire weather danger across the region. The recent dry weather would suggest cured vegetation is primed as evidenced by the projected erc 90th percentile forecast.
Low level moisture returns in earnest Thursday as south winds
continue over the region ahead of a weak front. Model soundings
and the character of the model qpf suggest that precip would be
more of a very light rain or drizzle thru the day. All of the
saturation on the sounding is 850mb or below. Without any
discernible focus for convection, the capping inversion on the
sounding should hold. However, by Thursday night the weak front
settles down into the Missouri Ozarks and across far northern
Oklahoma. Warm advection should aid in developing convection
across portions of northeast Oklahoma and Northwest Arkansas
during the overnight. Instability will not be sufficient at this
time to warrant a severe threat.
The boundary stalls for the time being from the TX panhandle to
The mo Ozarks as a strong upper trough approaches from the
southwest conus on Friday. Moisture quality will continue to improve south of the boundary with 60s dewpoints pushing up toward the I-40 corridor. The front will get a shove toward the east by afternoon as the upper trough continues east. Bands of thunderstorms are expected to develop along and ahead of the front Friday afternoon and sweep east across the forecast area into the evening. There will be potential for damaging winds and possibly a few qlcs tornadoes with any organized line segments, however the greatest severe threat will be along and to the east of a developing frontal low from the Arklatex up into central and
Eastern Arkansas where storms will have access to the true warm sector.
Some locally heavy rainfall is expected from far eastern Oklahoma into western Arkansas where the bands of storms will sweep across. It does appear this activity will be progressive and should shift east of the region Friday night. This should limit the overall flash flood threat, but a decent swath of 1 to 2 inch rains are possible and could lead to some main stem river flooding.
Now for the icing on the cake. Colder temperatures will filter into the region Friday night into Saturday behind the advancing front. Meanwhile, looking aloft, the aforementioned shortwave trough and embedded pv max are expected to track northeast right
Across the region on Saturday. The ecmwf has been very consistent in developing a wrap-around SW to NE oriented band of precipitation along the mid level deformation zone north of the Pv max across northeast Oklahoma into northwest Arkansas. Cooling thermal profiles suggest a transition to a wintry mix across Northeast Oklahoma and northwest Arkansas before changing over to all snow by midday. Again, the ecmwf has a few tenths of an inch of qpf along the wrap-around band where the thermal profiles favor wintry precip. The gfs shows a similar idea but has the band farther north across eastern KS into MO. We are still several days
away from the event and the exact details will likely change, but the possibility of impactful wintry weather Friday night into Saturday is gradually increasing.
If snow does indeed fall, it will not stick around long. A quick warm up is expected once the storm departs.