WKU Meteorology

Discussion of Mid-South weather and climate and information about the WKU Meteorology program

WKU Meteorology - Discussion of Mid-South weather and climate and information about the WKU Meteorology program

WKU Storm Chase Day 9 Recap

After spending the night in Wichita Falls, TX, the group had decided on an initial target of Weatherford, OK with the anticipation of driving northward to position ourselves near the triple point. The triple point is defined as the point where 3 boundaries intersect and in this case was where a warmfront, coldfront, and dry line intersected with a developing low pressure center in western Oklahoma.

Aside from the increased lift and shear provided by the triple point, this target was chosen because an axis of instability with CAPE values near 4000 J/kg resided up to and near the triple point, under a very weakly ‘capped’ environment. Also an upper level impulse with northwesterly flow was forecast to slowly deepen and provide an environment favorable for supercells or multi-cellular storms.

The only limitation from today was the higher cloud bases and very modest low-level flow, that likely limited the tornadic threat. Nonetheless, with minimal expectations of tornadoes, we knew we would at least get to see some terrific structure, and boy did we!

After finally stopping for a sit down lunch, and one other than Subway, moved northward to the warm front and watched cells initiate near O’Keene, Oklahoma. After some initial linear development the southernmost cell began to rotate and move southeast towards Kingfisher, OK.

Photo by: Nathaniel Shearer

Not long after, the storm began to progress and root itself in the boundary layer,  and the group got to witness a wall cloud that briefly took shape as the storm cycled In Kingfisher.

Kingfisher Wallcloud. Photo by Nathaniel Shearer

Near Peidmont, which is a suburb of Oklahoma City, the storm quickly intensified, as another storm from the south interacted with it and was absorbed into the parent storm’s updraft. This likely caused an increase in low level shear and lead to the birth of what may have likely been a rain wrapped tornado. There were reports from other spotters that this indeed was the case, but was not readily visible from our location.

Photo by Nathaniel Shearer

What was visible from our safer location, was truly the most remarkable structure in a thunderstorm that I have yet to see. It by far exceeded the ‘idealized’ storm that is often noted in textbooks, and the students got to witness this first-hand in the Meteorology laboratory that is the American Great Plains. It truly is an awesome sight that a picture can do no justice in describing.

Photo by Emily Yates

Despite narrowly ‘missing’ a tornado, the forecasted main risk for the day was high winds and large hail which all occurred. We were able to witness the high wind after dark (no pictures) as a 71 mph wind gust was recorded at a Oklahoma mesonet station near our location near Minton, OK. The high winds presumably knocked down power lines and we observed many large ‘power flashes’ as transformers blew and knocked out power to the nearby town. Also many reports of hail the size of 5″ were collected from this massive storm.

Photo Taken from Reed TImmer's facebook fan page

Another special treat was we happened to see Mike Bettes and the Weather Channel’s crew do a live broadcast on the side of the road as we all watched a nice storm west of (and out of) Oklahoma City, just after dark.

After a long and successful day, we have finally settled down in Stillwater, OK with eyes on another great chase day tomorrow, which looks to be as good, if not better, than today.

Field Methods in Weather Analysis and Forecasting…..its on again!

Hello readers,
Now an annual event, yesterday 8 students and 2 professors embarked on a journey across the great plains to forecast and verify severe convection. This ‘storm chasing’ class is meant as a capstone experience for young meteorologists to perfect their forecasting skill that they were lectured on at WKU. Daily updates on this blog will begin today, and run through the next 13 days. The blog posts will cover forecasted targets for severe weather,as well as chase day recaps and just our entire journey as us students experience cool things along the way. For those in the ‘twitterverse’ we will aslo be frequently updating our trip @wkustormchase on twitter.

Our journey began yesterday by leaving from Bowling Green, and ended last night ,after 600 miles of driving, in Kansas City, MO. Maybe its a precursor of things to come, but we got to drive through a weak squall line on the way out. At sunset, we were treated to a great view of yesterdays solar eclipse.

Today is being treated as another driving day as we target the Dakotas for tomorrow. A low pressure center is forecast to deepen as moisture begins to return along the front range. Full details will be blogged tomorrow, but this appears to be our first chase-able day. Sufficient instability, forecasted dew points in the 60′s, as well as ample shear, will provide an environment conducive to severe convection. Stay tuned !

 

High pressure and northwest flow equals cooler temperatures

The weather across Bowling Green this week has been quite tranquil with high pressure in place.  The big story has been the change in temperatures with lows in the 30s and highs in the upper 50s to lower 60s.  Monday of this week the the high was 74 degrees and last week (April 2nd) was 85 degrees.  That is a 11 degree difference in high temperature in a week.  The low temperature was even more drastic with a low of 63 degrees last Monday and this Monday low of 39 degrees.  This is a 24 degree drop in temperature aided by radiational cooling with strong high pressure in place and northwest flow.  As the high pressure moves to the east the area will experience warm up for the weekend with return flow around the high pressure. High temperatures will get back into the upper 70s to lower 80s and low temperatures in the lower 60s.

By: Dustin Jordan

 

Pattern Change

Highlights
• Pattern change for the rest of the week
• Cooler temperatures and chances of precipitation through the weekend

Forecast
Deep upper level trough that has been producing heavy rain and severe weather in TX through the week, will cut-off and slowly drift across our region through the weekend. With enhanced lift and a cool core aloft will allow for showers and thunderstorms to develop starting Thursday. A cool front will then proceed through early Friday morning bringing temperatures down to more seasonable. QPF amounts vary, but not expecting near the intensity experience across the southern plains. Bottom line is temperatures will top off near 79 with heavy cloud cover and thundershowers Thursday with a low around 60 as the cold front approaches. Temperatures will continue to fall with higher precip chances Fri and a high and low of 70/55. Rain should end by Sunday with partly cloudy skies and a high near 70.

Persistance

Highlights
Persistance forecast with high temperatures in the low 80’s and low’s around 60.
Forecast
As the upper level ridge and respondant low level southerly flow continue to amplify, our sensible weather will remain much of the same through Wed. All of the upper level dynamics are cofined to the highly dug trough over the central plains that will most likely cut-off and effect our weather for later this weekend. The only chance of precip looks to be Wed, and this will be highly dependent on how much instability is advected into our region that day. For now the period looks to be mostly dry.

Cooldown this weekend

Highlights
Seasonal temps through Fri. with a small chance light precip Friday.
Ridging in the Western U.S. to allow arctic air to invade the Eastern U.S. resulting in below average temps. this weekend

Forecast
High pressure at the surface and zonal flow aloft, will keep us dry and seasonable with highs in the mid 40′s and lows in the upper 20′s on Thursday and Friday. On Friday a wave ejecting out of the southwest will bring us our next system with a chance of light rain on Friday, ending with a chance of light snow Friday night. Little impact is expected with this system, as it is moisture starved and if there is any precip the change over to snow will be brief as the system’s attendant cold front rapidly swings through. The bigger story is the much cooler temperatures this weekend as Canadian air comes to the region with highs in the mid 30′s and lows in the upper teens to lower 20′s. Brrr!

Drying to start the week, patern change on tap for the eastern U.S.

Highlights
• Drying to continue, warmest temps on Tue.
• Pattern change with a slight chance of drizzle/flurries late Tues. night
Forecast
The upper level low that has kept our weather cool and damp, will be moving off to the east to start the week. Dry northwesterly air will move in on Monday keeping us mostly clear with a high of around 53. As high pressure returns to the region, good radiational cooling will allow temperatures to dip below freezing Monday night with a low of around 30. As our next system approaches, Tues will be marked by increasing clouds with mostly sunny conditions the majority of the day and a high around 54. Tues. Night the pattern changes as a trough starts to dig in to the Western U.S. Initially, on early Wed., a dry cold front will bring a small chance of light precip Tues. night with lows near freezing. Wed will be cooler and 44, before temperatures moderate with another cool shot of air this weekend.

Pattern Change

Highlights

Trough digging into the eastern U.S. bringing with it much cooler temps

Chances of rain through Fri.

Discussion

Currently, there is a trough of low pressure beginning to dig into the eastern U.S. that will change up the weather for the short term. A cold front currently over northern Indiana will pass through BG late tonight cooling off temperatures and bringing in some much needed rain.  Today’s temperatures will max out around 76 with a slight chance or rain.  The best chance of rain comes tomorrow with temperatures topping out in the mid 50′s for Thursday and Fri and lows staying in the low 40′s.

 

November-January Outlook…according to the CPC

Since the weather is relatively tame today, we will take a moment to discuss the long term outlook leading into this winter.

For long term climatic outlooks The Climate Prediction Center compares various climactic oscillations as well as atmospheric teleconnections, along with some history, to use past events with similar conditions as an analogy to the current state of the atmosphere.

That being said, the CPC has issued there report for the Central Region of the U.S., which includes KY. From following changes in the El Nino/Southern Oscillation. ENSO and the change in Sea Surface Temperatures across the Pacific Ocean, is considered to be one of the major players in sensible weather here in the United States.

From verifications of SST anomolies and forecasted products from this summer. Modeled guidance as well as the CPC both agree that a weak La Nina will persist and strengthen slightly through the beginning of winter.

Based on prior history and the fact that Texas has had record drought, this will likely cause the polar jet to stay mostly across the northern United States and more zonal causing an above normal chance of precipitation in the Pacific Northwest. This is to be taken with a huge grain of salt, as other factors such as the North Atlantic Oscillation can have changes in the sensible weather from week to week. This is a 3 month forecast.

Great Weekend Weather

Hightlights

Warming trend through the weekend

Partly sunny with a small chance of rain

Forecast

The weekend weather is shaping up to be a nice one! The cut-off low that has been dominating our weather this week with cloudy skies and drizzle, is finally opening up into a longwave and translating downstream.

Under suface high pressure and southwesterly flow, highs will reach 80 on Saturday and sunday under partly cloudly skies. This warming trend will continue into next week with more seasonably temperatures into the mid- 80′s. Another update will come soon, but in the mentime, enjoy this nice weekend!