Keeping An Eye On The Gulf Of Mexico

It’s that time of year again! Tomorrow is the official start of the Atlantic hurricane season, and we’re already going to have to keep a close watch on the Gulf of Mexico next week. While not as common, it’s not unheard of to have a June tropical system develop in the Gulf of Mexico or western Caribbean.

First, let’s talk about the tropical depression off the southwestern coast of Mexico. Tropical Depression Two-E currently has sustained winds of 35 mph and is moving slowly northeastward towards Mexico. This system is quite disorganized, although some strengthening could occur. Given how mountainous the terrain is just off the coast of Mexico near the potential impact zone, this will keep this depression weak, but flooding could be a big issue across the region.

tropical depression two-e

While this depression will not make it across Mexico as is, the overall pattern is going to be favorable for the advection of deep, tropical moisture into the Gulf of Mexico from the eastern Pacific. Precipitable water values will be increasing through the remainder of the week, particularly across the western and central Gulf of Mexico. Precipitable water content values simply indicate how much rain would fall if all moisture were to precipitate out of a vertical column of air extending from the surface to the top of the atmosphere. The higher the values; the wetter the air mass.

As mentioned on Firsthand Weather earlier this week, a mid to upper level trough is going to develop and dig across the eastern U.S. early next week. This feature will be responsible for bringing an unseasonably cooler air mass across the region, which will ultimately result in below average temperatures all the way to the Gulf coast (and yes, even a less humid air mass for many!). Associated with this trough and its embedded shortwaves will be a surface low pressure system that will develop and move to the East Coast sometime early to mid next week. In the image below, you can see the cold front that will extend to the Gulf coast from the surface low along the East Coast. Early in the hurricane season, it’s not uncommon to have tropical activity develop along a frontal boundary that has made it to the Gulf of Mexico. It acts to enhance convection, and if other factors are favorable, some organized development can happen.

Cold front moving through U.S

Mean sea level pressure will generally be on the decline across the Gulf of Mexico from this weekend onward into next week. The first image that I have included below indicates above average sea level pressure across much of the Gulf of Mexico currently, but surface pressure values will drop towards the weekend, which is shown in the image below that. This is a more favorable environment for tropical development.

Gulf of Mexico mean sea level pressure this week

Gulf of Mexico mean sea level pressure next week

While it’s difficult to say whether or not we’ll have a tropical depression or storm in the Gulf of Mexico by later this weekend into next week, the main focus should be on the flooding situation that could evolve as a result of this setup. With the cold front moving southward along the Gulf of Mexico and with a mid to upper level trough positioned over the eastern U.S., this would generally favor any system, whether fully organized or not, moving along the Gulf coast and into Florida. Again, the main focus needs to be on the moisture-rich environment and overall setup that could result in heavy rains from Louisiana to much of Florida. Basically, those located along the Gulf coast and just north (this’ll depend on the placement of the frontal boundary) need to keep an eye on the flooding situation that could evolve this weekend into next week.

Severe Storms and Tornadoes Possible in Texoma Today

Severe thunderstorms are possible across Texoma this afternoon and overnight. These storms may produce tornadoes, very large hail, and damaging winds. The Storm Prediction Center (SPC) has an enhanced risk of severe thunderstorms for the Oklahoma Counties of Texoma and a slight risk for the Texas Counties of Texoma (it should be noted there is a moderate risk northeast of Texoma).

SPC Thunderstorm Outlook

There are some uncertainties with the evolution of today’s thunderstorm event, so let’s get straight into the possibilities. By late this afternoon, a sharp dryline will establish itself just west of I-35 in Oklahoma and Texas. The atmosphere will be extremely unstable, thus, any storm that could develop along the dryline would likely produce softball sized hail and isolated tornadoes. However, there is a strong CAP in place at this hour. The CAP will continue to weaken as afternoon heating takes place. This could allow one or two storms to develop near the dryline in Texoma. This scenario, again, is very questionable due to the CAP but we will need to keep an eye on the dryline as it moves towards I-35 between 4:00PM-8:00PM. The latest short-range hi-res model (HRRR) is indicating the possibility of isolated convection developing along the dryline this afternoon.

HRRR Future Radar For This Afternoon

The more likely scenario is thunderstorms eventually developing across central/southern Oklahoma along a southward advancing cold front. This scenario is more likely because of the strong forcing associated with the front, which compromise the CAP. Thunderstorms that develop along the front will form into a southward moving complex that will likely produce damaging winds, hail, and isolated tornadoes across Texoma.

HRRR Future Radar For Tonight

Moderate Risk for severe weather across the Plains

Severe weather is expected from the Red River Valley through the Ozarks and into the Tennessee valley.  Large to giant hail, widespread severe wind gusts and Tornadoes are anticipated.

A mid-level trough is moving into the northern Plains and will continue to advance eastward.  The trough should reach the upper Mississippi and Missouri Valleys by tonight.  This trough will bring several smaller disturbances across the Plains and mid to upper Mississippi Valley today.

In the western portions of the risk area, from Central and Eastern Oklahoma as well as northern Texas, there will be strong capping in place.  That cap will prevent storms from forming earlier in the day but as lifting forces increase throughout the afternoon, some storms will form and develop rapidly due to favorable profiles.   The overall risk is lower from the Red River Valley up into Northeastern Oklahoma due to this cap, which will allow the cold front to form a line of storms, but any supercells that form before the passage of the front has the potential to be dangerous.  Strong tornadoes and giant hail are risks in these supercells, though the risk becomes more limited the further south you go into Texas.

Further north and east, The potential exists for a swath of damaging wind gusts to occur from eastern Kansas to the mid Mississippi Valley this afternoon and evening.  There are some questions about the development of storms along an outflow boundary this morning from the current storms taking place.  Additional storms this morning would help limit the risk in this area, but capping over the area is expected to keep the number of early morning storms low and keep the risk higher this evening.  Do not be surprised if the Storm Prediction Center puts out an area of high risk later on this morning if only small amounts of convection form and a better location for the deep convection is ascertained.

This convection will all begin to take a linear form as the cold front continues to push east and a convective complex is possible along the cold and warm front that’s will be in the region.  This will approach the Mississippi Valley this evening and into tonight.



Southern Plains Tornado Outbreak Possible Today

Damaging thunderstorms and strong tornadoes are likely across parts of the Southern Plains later today into the overnight hours. The Storm Prediction Center (SPC) has a high risk of severe thunderstorms across northern Oklahoma and southern and central Kansas; a moderate risk for much of central Oklahoma and Kansas surrounding the high risk area; an enhanced risk from northwestern Texas through parts of Oklahoma and Missouri, which is surrounding the high and moderate risks; and a slight risk for much of northern Texas down into the Texas Hill Country.

Thunderstorm Outlook (SPC)

A high risk, which is rare, is a category 5 risk on a scale of 1-5 (with five being the most significant). By SPC definition, a category 5 risk means this area can expect widespread severe weather with several widespread long-lived damaging thunderstorms. This is a particularly high probability of strong tornadoes today for parts of Oklahoma and Kansas.

Severe Thunderstorm Risk Categories (SPC)

This afternoon, strong upper-level winds will move into western parts of the Southern Plains as a powerful upper-level low advances towards the region. Currently, deep and rich moisture has moved into northern Texas (dewpoints are >70 degrees); this moisture will continue to advance northward, setting the stage for a very unstable environment. This will lead to explosive thunderstorm development by the afternoon hours (after 3:00PM) in western Oklahoma and western Kansas once the dryline sharpens and creeps eastward. With the initial mode of thunderstorms expected to be discrete and supercellular, they will likely produce tornadoes due to the deep-layer shear and very conducive low-level shear.

Thunderstorms by the evening should begin to slowly merge to develop a complex, which would aid in an area of enhanced wind-damage potential. The best area to see damaging winds from this complex are across central and eastern Oklahoma as well as northern Texas (around 9:00PM). It should be noted that some of the short-range guidance is indicating thunderstorms may develop during the early afternoon hours across southwestern Oklahoma/northwestern Texas. This could throw a ‘fly’ into the forecast because it could act to lessen the severe threat for this area and possibly areas further north. I will keep a close eye on this scenario to see how it plays out.

Again, an outbreak of severe thunderstorms is possible for the Southern Plains this afternoon. All modes of severe weather are possible. This forecast is not intended to create hype or worry you. I am simply implying the severe threat is real today if all the parameters come together as the numerical guidance is indicating. Do not panic, just have a plan in place. Tune in to your local television station so you’re notified of warnings, call your elderly neighbors to make sure they have a plan, and know where you will shelter in case a warning is issued for you area.