However, as the atmosphere continues to become more conducive to severe weather through continued warm air and moisture advection overnight, will not rule out severe weather tomorrow morning, especially given expected values of elevated instability that may favor stronger storms. I do believe hail is a primary threat with these storms, especially in their elevated nature, but again, I am not completely sold on the idea of severe and/or significant hail. Not completely convinced we see hail threats as advertised by some, including the threat of up to tennis ball-sized hail as per NWS OUN in their hazardous weather outlook posted yesterday. The new SPC Day 1 outlook has placed central and southern Oklahoma in the Enhanced Risk of severe weather, primarily for potentially significantly large hail, in addition to damaging winds and a non-zero, yet relatively low tornado threat. Lower level winds just 5000′ off the ground will be over 60 knots, and if these winds translate to the surface, we could see a large-scale damaging wind event over the Ohio Valley.

The active jet stream will lead to this event being maximized in the severity, in terms that whatever severe weather that occurs on Sunday should be of decent significance (i.e. damaging winds and possibly a tornado). The image above shows the jet stream wind speed projection for Sunday evening. Simulated reflectivity projections from the NAM model indicate that a strong squall line should stretch from Ohio to the western tip of Tennessee by the evening hours on Sunday. The jet stream should be absolutely screaming when this event begins, with the NAM forecast above maxing out above 110 knots. In similar fashion, above normal sea surface temperatures (SST’s) in the Nino 3.4 region correspond to the term ‘El Nino’. The image above shows the surface condition map on the left and 500mb map on the right from December 14, 2013. If w extrapolate that date out 57 days, we come to the February 9th mark.

It seems I miscounted a bit, and the 57 day period from December 14th goes out to February 9th, rather than 7th. Therefore, this December 14th system looks to correlate with the February 9-14 storm threat. Using Joe Renken’s idea that a storm system over Japan correlates to a storm system in the United States 6-10 days later, we can project that a storm system will hit the United States around a February 9-13 time period. Above, we see the 500mb height anomaly forecast for the evening of February 3rd. We see a strong trough digging southeast towards Japan. Convection-allowing model guidance has been promoting the formation of showers and thunderstorms along the Red River, most notably in southeast Oklahoma in the mid-morning hours today, following expected overnight precipitation and continued moistening of the lower levels. 3/30 00z KOUN sounding showed strong temperature inversion between 800-millibar and 700-millibar levels, and I suspect this inversion will be strong enough to suppress anything more than broad, generally-weak precipitation.

At the time, storm motion (storm speed) around 50-60 knots to the east-northeast tells me that this will certainly be a big damaging wind threat. Also supporting this potential storm system is the Lezak Recurring Cycle. Large upper level low currently stationed across the Western US will provoke a potential severe weather event in the Plains and lower Mississippi Valley today. To summarize, potential severe weather event is on the table today for the Southern Plains into the lower Mississippi Valley, with high uncertainty still included in the forecast. There is potential for a severe weather outbreak this weekend, as an amplified storm system traverses the Plains, leading to an enhanced jet stream and an opportunity for a potentially significant squall line. PNA ridge. Sweetening the pot is evidence of a very slight ridge in the Southeast, something that could allow any potential storms to move more northward. In the 12z GFS model, we saw a storm system dig southeast into the southern Plains before going negative tilt, and eventually closing off as it began to move north. A front will move east from the Pacific to the Northern Plains over the weekend, the weather service said.