Disturbance in the Gulf of Mexico Will Bring Heavy Rain and Muggy Weather

Ridging has continued to build over the southeastern quadrant of the United States over the last few days, which has been responsible for a large region of anomalously hot temperatures and drier air. This ridge is currently centered over eastern Arkansas and western Tennessee but will begin to split as a mid-to-upper level closed low moves from the eastern Gulf of Mexico and into the Southeast early next week. Given that ridging is associated with sinking air which often limits storm development, the splitting of this ridge will result in a drastic change in sensible weather conditions in the coming days.

The National Hurricane Center has outlined a disturbance in the eastern Gulf of Mexico and is giving it a 40% of tropical or subtropical development over the next 5 days. Even though the Atlantic hurricane season doesn’t technically begin until June 1, it wouldn’t be a big surprise to see a weak subtropical/tropical disturbance develop, if convection (thunderstorm development) can consolidate over a small enough region in the Gulf. The upper-level trough/closed low (the feature that is splitting the ridge over the Southeast) will continue interacting with a region of broad surface low pressure moving into the Gulf, which should assist in its further development since the upper-level dynamics will be supportive. Whether or not we get our first named system out of this is not necessarily important from a sensible weather standpoint. The impacts will be about the same regardless, which is what the primary focus should be on.

5-day NHC tropical outlook

Let’s talk about potential impacts and how the weather should change compared to last week/this weekend. The mid-south (Louisiana, Arkansas, most of Mississippi, most of the Southern Plains, and areas just northward) will remain quite toasty for a large part of the week since the closed low and developing surface low should remain to the east/southeast of those regions. However, farther east, temperatures should be cooler due to enhanced rainfall for most of the week, but the transport of deeper moisture into the area will result in muggy conditions, making temperatures feel warmer. Instead of trying to put all of this into words, take a look at the map from the Weather Prediction Center (NOAA) that shows the projected rainfall totals over the next 5 days. Don’t focus as much on exact amounts, but take note if you’re located in a region that is expected to get more than a couple of inches of rain (purplish/reddish-shaded regions).

5-day wpc rainfall forecast

The big impact will be the heavy rainfall, although that’s not necessarily a bad thing since many areas have recently been dry. However, be wary if flash flooding begins to occur and do not attempt to drive over any flooded roadways. As the rainfall map indicates, heaviest rainfall totals over the next several days should occur from Florida through Georgia, parts of Alabama, the Carolinas, and up the East Coast. Another zone to keep an eye on will be from the Ohio Valley into the Mid-Atlantic, where a frontal boundary will remain stalled out over the region. Given that this region is located along the periphery of the current ridge, winds have been westerly/northwesterly through a deep layer of the atmosphere, and disturbances will continue to be embedded within the westerlies, so storminess may be a bit more intermittent and hit-or-miss across that area. Also, this is where the severe weather threat (mainly a damaging wind threat) will be concentrated this week, along with a severe weather threat across parts of the Great Plains. Firsthand Weather will address those risks on a day-to-day basis. Partially due to the moistening of the environment through a deep layer farther south across the Southeast, this should mostly limit the severe weather risk, since temperatures will not decrease with height as rapidly (resulting in lower instability). We’ll still keep an eye on it just in case though.

To briefly summarize, expect a change in weather conditions across a large region. Many will be transitioning from a dry and hot pattern to a warm, muggy, and wet pattern. Given the position of the large ridge, the low in the Gulf of Mexico will not be in a hurry to move out and will have to be swept out by an incoming trough later in the week. This is particularly important information to keep in mind if you intend on hitting the water for fishing or other watersports activities. These towers way north of Key West in the gulf are a prime location for fishing but will be buffeted by the weather so be sure to stay safe. In the meantime, get used to the wet (or at the least, muggy) weather!

Tropics heat up as Franklin moves ashore

The tropics have been heating up as Tropical Storm Franklin has moved ashore on the Yucatan Peninsula this morning.  Franklin continues to batter the region with heavy rains and high winds.  Current sustained winds are 60 mph with rainfall expected to cause significant flooding and flash flood conditions. A storm surge of 2-4 feet was expected and major evacuations have occurred in low lying communities in Mexico.   Tropical Storm Warnings continue from Belize City to the Gulf coast of the Yucatan at Sabancuy at this time.  Franklin is expected to move into the Gulf of Mexico later on today.

Tropical Storm Watches are in effect from Sabancuy to Puerto de Veracruz along the southern portion of the Gulf of Mexico.   Once in the gulf, Franklin is expected to intensify and as we mentioned on Sunday, Franklin is going to come very close to hurricane strength before making a second landfall in Mexico.  To account for this, hurricane Watches are in effect from Puerto de Veracruz north to Rio Panuco.  Some of this area will be downgraded to a Tropical Storm Warning as Franklin approaches, as the hurricane wind field will not be that big.  The large area is simply to take into account possible changes to the track.

As we have stated before, Franklin is not a threat to make landfall in the US.

Tropical Atlantic

In other news for the tropics a tropical wave roughly 1000 miles east of the Lesser Antilles continues to be disorganized at this hour.  Environmental conditions remain poor for development over the next couple of days.  Conditions begin to improve as this system moves north of the Lesser Antilles into the region around the Bahamas.  Some models have developed this system and bring a tropical risk to the east coast of the United States so we here at Firsthand Weather will be watching this system closely.

 

Robert Millette

Severe weather moves from the Plains towards the Mid-Atlantic

Severe weather is a risk over the next couple of days from the Plains and Gulf Coast regions into the Appalachians towards the Mid-Atlantic.  While there is a low risk for tornadoes, there are significant risks for widespread damaging winds and  large hail.

A stationary front has been the focus for strong to severe thunderstorms over the Plains in recent days bringing over 900 reports of severe hail and wind from Texas to Wisconsin.  This front is interacting with a strong, fast moving cold front that will create the lift needed for a large area of showers and thunderstorms.  Some of these storms could be intense this morning as remnants of a Mesoscale convective system died out overnight across the Plains persists.  The severe weather moves on into the Appalachians by Sunday, and on to the Mid-Atlantic up into New England for Monday.

Saturday

The cold front, along with a strengthening low pressure system, will continue to progress southeastward from Central Iowa into Central Kansas.  The air ahead of this front remains warm and unstable with plenty of moisture.

Storms are likely to begin over Iowa and northern Kansas before spreading East from Michigan down into Missouri.  These thunderstorms are expected to form into linear squall lines over time due to weak low level shear yielding outflow dominant storms.    Any storms should begin to weaken after nightfall as they move east, where lapse rates will be lower.

Sunday

Scattered thunderstorms, with a primary risk of damaging winds, are expected from the Great Lakes into Northeast Texas.  The low pressure from Saturday will move from the Great Lakes into Canada but the cold front will remain across the Ohio Valley into the Southern Plains.

From the Great Lakes down through Tennessee, early remnants from overnight storms should clear with a moisture rich warm air-mass in place to meet the weakening cold front.  The ongoing wind regime should allow for strong multi-cluster cells to form.  Hail may also fall but will only be locally severe.

Further south, storms will be more isolated from the Texoma region into Arkansas.  Lift in this region will be weaker but the cold front will be a focus point for thunderstorms due to an elevated mixed layer and moist low level conditions.  These will form a very unstable boundary layer that could see the convective available potential energy (CAPE) approach 4000 Joules per kilogram.

In Mississippi and Alabama, scattered thunderstorms will develop during the daytime heating period.  Seasonably warm and moist air will become more unstable under conditions that have very little convective inhibition.  Strong to severe cells that do form will likely have marginally severe hail and localized damaging winds.

All southern storms should begin to weaken during the evening hours as daytime heating fades.

Starting off the work week, the Northeast and Mid-Atlantic are looking at pending severe weather as the cold front pushes east into more warm moist air Monday afternoon into the overnight hours effecting all the major metropolitan areas.

Rob

 

 

Severe weather risk continues for the next few days

After yesterday’s severe weather across parts of Oklahoma and Texas, storms have spread to the east.  Severe Thunderstorm watches are in effect across several states from now until tonight.

Severe Risk

A trough across Missouri this morning moved eastward to the middle Ohio River Valley and will arrive by late tonight. A belt of 40-50 kt west-southwesterly mid level winds will continue to overspread an increasingly moist warm sector. A cold front has moved across the Ozarks and Ark-La-Tex region and continues east through Kentucky and Tennessee down to the Gulf Coast.  Organized convection across far northeast Arkansas far southeast Missouri from late this morning has spread east-northeastward and increased in coverage and intensity into Tennessee and Kentucky. This activity will pose a damaging wind and severe hail risk, although a tornado cannot be ruled out.

Farther south, more discrete storms have developed within the warm sector this afternoon across additional portions of Tennessee, northern Mississippi and northwest Alabama.  A supercell-favorable wind profile and steep mid-level lapse rates will support large hail potential. A few tornadoes also appear possible,  particularly into early evening across middle portions of Tennessee and northern Mississippi and northwest Alabama.   In this corridor, a modest westerly component of the mid-level winds  and modestly strong low-level shear coincide.

Severe

Tornado Risk

Hail Risk

Wind Risk

Current Watches

A Convective line stretching from near Huntingburg Indiana southward across central Kentucky and middle Tennessee and into northwest Alabama is expected to continue moving eastward over the next few hours. The downstream airmass is generally cooler and has less overall instability. However, the line is well-organized and the bulk shear
is expected to remain relatively constant for the next several hours. Near-severe gusts have been measured at several sites as the line moved through. The ongoing severe threat will persist for the next few hours.  A threat is possible downstream in eastern Kentucky, Tennessee and far northwest Georgia and a watch has been issued for this region.  Additionally, the cluster of storms ahead of the line in eastern Kentucky pose an isolated hail and damaging wind threat.

Current warnings

 

 

Robert Millette

 

Severe weather comes to the Northeast

Severe

Severe weather threat for the Northeast

Severe weather is expected today in the Northeast and the Storm Prediction Center has out most of the region under a slight risk from eastern New York and northeast Pennsylvania up trough all but the south coast of New England   Remaining locations in the aforementioned region are under a marginal risk for severe weather.

Severe

Summary

Damaging winds and hail are the primary threats as a cold front moves through the region.   Dry conditions are impacting some areas to the north but southerly flow is moistening some areas through the day.

A shortwave trough, now evident in moisture channel imagery, is shifting east through Canada.  This system is bringing a cold front southeast, stretching across New England into the Great Lakes.

This frontal boundary, along with a wind shift from Maine down to the mid-Atlantic will be the primary focus areas for thunderstorm development from mid afternoon into the early overnight hours.

Deep shear is expected to strengthen this afternoon along with upper level height falls as the system approaches this afternoon.   These factors should occur at the same time as the maximum heating and boundary layer destabilization and could lead to supercell and multicellular cluster development.  Early cloudiness was not a major factor as temperatures are climbing into the low 90s to upper 80s in the majority of locations.

Should storms occur in your area, please remember than dangers that thunderstorms and flooding conditions can bring.  If you can hear thunder, you can be struck by lightning and even a small amount of water can float even heavy vehicles.

Stay here with firsthand weather for updates on this developing situation and also keep advised of your NOAA radio or local media sources for instant coverage of warnings in your localities.

Robert Millette

Staff Meterorologist

Firsthand Weather

Southern Plains Storms

As expected this time of the year, it has been hot and oppressive across the Southern Plains this week. Luckily, changes are in store beginning tomorrow (Friday). An approaching upper-level trough will push a cool front into northern Oklahoma late tonight into Friday. This cool front will provide adequate lift to generate scattered thunderstorm activity along and north of I-40 in Oklahoma, southern Kansas, and parts of the Texas Panhandle. Any thunderstorm that develops tomorrow has the chance to become severe. The main threats are damaging winds and large hail.
Slide02
SPC Thunderstorm Forecast (Friday)

Heavy rainfall is possible with the thunderstorm activity on Friday, too, and the rain chances will continue through Sunday. These rain chances will continue throughout the weekend due to a couple upper-level disturbances moving across the area. 1-2″ is possible north of I-40, and for parts of the Texas Panhandle; with isolated higher amounts.
Slide03
NAM Rainfall Forecast Through The Weekend

While most of southern Oklahoma and northern Texas wont see widespread rain chances. A few thunderstorms are possible for these areas; however, the more widespread activity will remain further north. Areas that do not see rainfall/cloud-cover can expect temperatures and humidity levels to remain uncomfortably high.

Sunday Severe Storms

Showers and thunderstorms are ongoing across parts of Oklahoma and northern Texas this morning. This activity will continue to progress towards the east throughout the morning hours before new activity ignites. A cool front is slowly pushing into central Oklahoma this morning, coupled with a shortwave trough rapidly approaching the area; this will be the focus for new thunderstorm development this afternoon.
Slide02
HRRR Simulated Radar For This Afternoon

Some of these storms will likely be strong to severe and the Storm Prediction Center has a slight risk for severe thunderstorms for most of eastern Oklahoma. Damaging winds, large hail, very heavy rainfall, and frequent lighting will be possible with any thunderstorm.
Slide04
SPC Thunderstorm Forecast (Yellow Area: Slight Risk)

The heaviest rainfall will be along and east of I-35. These areas will see .5-1″ of rainfall with amounts as high as 2-4″ towards northeastern Oklahoma.
Slide03
HRRR Rainfall Forecast

If you’re on area lakes today, please remain on high alert in case a thunderstorm approaches your area. Regardless of thunderstorm chances, temperatures will be extremely hot. Heat indices will exceed 100, so stay hydrated out there. Another chance for thunderstorms exists for you 4th of July across parts of Texas and Oklahoma. I’ll have an update on this later this evening.

Southern Plains Storms

Shower and thunderstorm chances will continue across much of Kansas, northern Oklahoma, and the Texas Panhandle over the next few days. Isolated thunderstorms are ongoing across parts of the Southern Plains this evening, but more widespread activity is expected to develop in eastern Colorado/western Kansas and propagate towards northern Oklahoma tonight into early Thursday.

By Thursday evening a weak cool front will advance into Kansas and north of I-40 (in Oklahoma) by Friday morning. This boundary will be the focus for several rounds of showers and storms for Kansas as well as northern and central Oklahoma. Heavy rainfall is likely during this setup; most areas north of I-40 will see 1-2″ with isolated 3-6″ possible. This could create flash flooding for localized areas during the day on Friday. Isolated damaging winds and large hail is possible with any storm over the next few days, and lightning will be a major concern for those who have outdoor plans.
Slide02
Potential Rainfall Totals (Next 5 Days)

It is important to note that the area will see a northerly flow aloft, so some of the thunderstorms that develop in northern/central Oklahoma may move further south than the models indicate. This will keep scattered rain chances in the forecast for southern Oklahoma as well as northern Texas, but the greatest coverage will be north of I-40.

Rain chances will subside for northern Texas and much of Oklahoma on Saturday, but appear to return later in the weekend. These rain chances will be bumped up a few notches on Sunday into Monday due to the upper-level ridge weakening. Temperatures will top out in the 80’s and 90’s the rest of this week so make sure you’re staying hydrated! I’ll have more details on the Monday (4th of July) forecast in the next day or two.

Rain Chances and Cool Front for Southern Plains

It has been hot across much of the Southern Plains over the past couple of weeks due to the persistent upper-level ridge. Rain and thunderstorms have been isolated at best, but that is about to change. Rain and thunderstorm chances will increase for parts of the Southern Plains this upcoming work week. Rain has already begun to increase across parts of western Texas and northern Oklahoma today. This is due to an upper-level low and cold front, respectively.

This cold front will move southward Monday night into Tuesday, generating an area of showers and thunderstorms that will propagate towards the Red River valley. Rain coverage will be about 40% and will continue throughout the day on Tuesday. Most areas will see less than 1″ of rainfall, but a few areas that get under the heavier storms could see a brief 1-3″.
Slide03
High Resolution NAM rainfall totals

The cold front is very weak, but the forcing associated with this boundary will not only generate storms, but cloud cover, too; which will knock highs down by about 5-10 degrees in some areas.
Slide02
High Resolution NAM temperatures Tuesday afternoon

Severe weather is not likely, but gusty winds and frequent lighting are possible.

Looking ahead towards the holiday weekend, it appears that the aforementioned upper-level ridge will shift towards the west-northwest. This is good news for the Southern Plains because this sets up a favorable pattern for afternoon and nocturnal thunderstorm complexes to impact the area. This is known as a northwesterly flow, and these patterns can produce very heavy rainfall and, at times, damaging wind events.
Slide05
Potential rainfall totals over the next seven days

Major severe risk across Ohio Valley

A moderate severe risk will bring widespread Damaging Wind gusts in excess of 70 miles per hour along with tornadoes and isolated large hail are expected this afternoon and evening from Northeast Iowa into extreme Southern Wisconsin, Northern Illinois, Southwest Michigan, North and Central Indiana and Western Ohio.  The wind damage threat will affect the Upper Ohio Valley Late this evening into the Central Appalachian Mountains during the overnight period. 

severe risk

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 50,489 17,159,246 Chicago, IL…Fort Wayne, IN…Aurora, IL…Dayton, OH…Rockford, IL…
ENHANCED 75,211 14,071,627 Indianapolis, IN…Columbus, OH…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…
SLIGHT 114,349 25,466,262 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
MARGINAL 242,590 39,815,217 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

A belt of stronger westerly winds will persist across the northern tier states including the Great Lakes and Ohio Valley.  There is a shortwave trough embedded within the stronger winds aloft.  This trough will move from Northern North Dakota to the Upper Great Lakes by this evening.  This trough, along with a surface low over Nebraska.  A warm front extends from this low through Southern Iowa and Southern Iowa into Southern Indiana.  This warm front will move north into Northern Illinois today as the low moves into Eastern Iowa this afternoon. 

Strong storms from this morning, which had prompted several Severe Thunderstorms this morning, shifted southeastward along the convectively enhanced warm front.  This movement was in response to a strong southwesterly low level jet stream.  As the Warm front moves north, moist low level air will bring dew points into the 70s from the Mid-Mississippi Valley to the Ohio Valley.  Storms will develop in the vicinity of and north of this warm front with supercells being the primary initial mode of storm.  Very Large Hail will be likely with the initial storms. 

Colin4

Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 25,480 10,316,848 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
30 % 12,213 4,222,164 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
15 % 90,996 18,409,308 Chicago, IL…Indianapolis, IN…Minneapolis, MN…St. Paul, MN…Fort Wayne, IN…
5 % 191,529 34,507,995 Detroit, MI…Columbus, OH…Milwaukee, WI…Cleveland, OH…Raleigh, NC…

 

There is a significant risk of Tornadoes with these storms, especially across Northeastern Iowa, Southern Wisconsin and Northern Illinois west of Chicago.  But the risk extends across the Ohio Valley into the Appalachians into the overnight hours. 

tornado outlook

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 24,082 6,403,348 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
10 % 41,673 13,277,336 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
5 % 71,076 14,627,057 Indianapolis, IN…Columbus, OH…Milwaukee, WI…Toledo, OH…Cincinnati, OH…
2 % 105,218 19,386,926 Detroit, MI…Cleveland, OH…Pittsburgh, PA…Lexington-Fayette, KY…Akron, OH…

 

Storms will grow upscale into a fast moving mesoscale convective system and Derecho.  The primary threat across the Ohio Valley into the Southern Great Lakes will be strong and damaging straight line winds.  Conditions appear favorable for a swath of significant damaging winds during the late afternoon and early evening. 

severe watch

Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 82,916 22,731,124 Chicago, IL…Indianapolis, IN…Columbus, OH…Cincinnati, OH…Fort Wayne, IN…
45 % 51,341 17,323,133 Chicago, IL…Columbus, OH…Fort Wayne, IN…Aurora, IL…Dayton, OH…
30 % 75,230 13,798,843 Indianapolis, IN…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…Akron, OH…
15 % 114,507 25,961,856 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
5 % 241,275 39,436,728 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

Robert Millette

Staff Meteorologist

Firsthand Weather