Tag: storms

A Calm Afternoon; More Severe Storms Tonight

| January 21, 2017 @ 9:32 am

After a very rough morning across Alabama, the storms have shifted into Georgia, an we expect a quiet afternoon with some sun breaking through the clouds and a high in the low 70s. But, another round of severe weather is likely late tonight and early tomorrow as a deep upper low approaches from the west.

ROUND TWO: The main window for strong to severe storms will come from roughly 11:00 tonight through 6:00 a.m. tomorrow.

Highest tornado threat seems to be over the southern half of the state; STP (Significant Tornado Parameter) values are highest there, with a good combination of instability and shear.

But, understand the chance of a tornado over North Alabama is not zero, just much smaller. Storms tonight will also be capable of producing large hail and damaging straight line winds.

Additional rain amounts of 1-2 inches could also create some flooding issues.

CALL TO ACTION: Be sure you have a way of hearing severe weather watches and warnings. At home, you need a properly programmed NOAA Weather Radio with a battery backup. On your phone, for warnings we recommend WeatherRadio by WDT. You can watch our live severe weather coverage on the free ABC 33/40 app. Here are the links…

ABC 33/40 iOS version for iPhones and iPads

ABC 33/40 Android version for Android phones and tablets

Review your action plan in case a tornado warning polygon includes your home. Get in a small room, on the lowest floor, away from windows, and near the center of the house. You do NOT have to be underground. Never be in a car or mobile home.

Stay tuned to the blog for updates throughout the day…

Friday Night Update

| January 20, 2017 @ 10:56 pm

A very active weekend is ahead for Alabama… with two rounds of potentially severe storms ahead.

A new tornado watch is bring issued for parts of Southeast Louisiana and South Mississippi through the early morning hours, and very active storms continue to develop quickly over Louisiana.

ROUND ONE: Severe storms will move into West and Southwest Alabama sometime in the 2-3 a.m. time frame… this is the forecast UH (updraft helicity) max through midday tomorrow, suggesting the highest tornado potential will be along and south of I-20…

In addition to the tornado threat, storms will be capable of producing hail and damaging winds. The main window for rain and storms will come from 3a CT until 9a CT; be sure you have a way of hearing severe weather warnings. A good app for this is WeatherRadio by WDT.

There will be a nice break from rain and storms from midday tomorrow through about midnight tomorrow night… the afternoon tomorrow should be pleasant with some sun at times and a high around 70 degrees.

ROUND TWO: We will have several waves of showers and storms from midnight tomorrow night through Sunday afternoon. With a generally unidirectional flow expected, the tornado risk is low; hail and gusty winds will be the main threat. It won’t rain all day Sunday, but a few passing showers and strong storms are likely.

Keep an eye on the blog for frequent updates through the weekend…

Complex Weekend Storm System

| January 20, 2017 @ 3:15 pm

QUIET AFTERNOON: We have a mix of sun and clouds across Alabama this afternoon with temperatures the low 70s; nothing showing up on radar. But, things get active over the weekend as a deep upper low forms west of the state, and unstable air moves northward.

Here is the latest thinking after viewing the new computer model data that arrived this morning…

ROUND ONE: The first opportunity for strong to severe storms will come early tomorrow morning, generally in the 3:00 a.m. to 10:00 a.m. time frame. High resolution model data suggests the best combination of instability, shear, and stronger wind fields will be over Central and South Alabama, generally south of I-20 (Tuscaloosa, Birmingham, Anniston and points south).

Storms early tomorrow morning over Central and South Alabama will be capable of producing large hail, damaging winds, and a few tornadoes. For now severe weather over North Alabama, north of I-20, looks unlikely early tomorrow morning.

TOMORROW AFTERNOON/EVENING: The main low level jet, about 5,000 feet off the ground, moves east of Alabama by the afternoon, and it sure looks like this could be a pretty quiet period with some sun breaking through the clouds along with temperatures approaching 70 degrees. But, the air will be rather unstable, and an isolated storm can’t be totally ruled out. But, generally speaking, we should be in a lull tomorrow afternoon and early tomorrow night with few, if any storms.

ROUND TWO: The next thunderstorm event comes Sunday with the upper low approaching. Storms could form as early as 2:00 a.m. Sunday, and the chance of storms will continue through the day, although by Sunday afternoon the stronger storms will shift down into areas south and east of Birmingham. Forecast wind fields are rather unidirectional, so for this round of storms it looks like the main threat will come from small hail and gusty thunderstorm winds… the tornado risk looks pretty low for now.

Rain amounts over the weekend should be in the 1-2 inch range, and flash flooding is not expected.

BOTTOM LINE: This is a pretty complex pattern, and understand there could be forecast changes as we get into the weekend, so keep up with the latest posts here on the blog. For now, the primary tornado threat seems to be early tomorrow morning over Central and South Alabama.

CALL TO ACTION: Be sure you have a way of hearing severe weather watches and warnings. At home, you need a properly programmed NOAA Weather Radio with a battery backup. On your phone, for warnings we recommend WeatherRadio by WDT. You can watch our live severe weather coverage on the free ABC 33/40 app. Here are the links…

ABC 33/40 iOS version for iPhones and iPads

ABC 33/40 Android version for Android phones and tablets

Review your action plan in case a tornado warning polygon includes your home. Get in a small room, on the lowest floor, away from windows, and near the center of the house. You do NOT have to be underground. Never be in a car or mobile home.

NEXT WEEK: Monday will be cloudy, windy, and much cooler with a chance of some light rain, mainly during the morning. The high will be in the low to mid 50s. Even colder air returns later in the week with highs dropping into the 40s. See the Weather Xtreme video for maps, graphics, and more details.

As always, watch me for the full weather story on ABC 33/40 News this evening at 4, 5, 6, and 10:00!

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus
Instagram
Snapchat: spannwx

I had a great time today visiting with the 3rd graders at Hillview Elementary in Forestdale… be looking for them on the Pepsi KIDCAM today at 5:00 on ABC 33/40 News! My next Weather Xtreme video will be posted here early Monday morning… Brian Peters will have the video updates tomorrow and Sunday. Enjoy the weekend, and check the blog often for updates…

Severe Storms Possible This Weekend

| January 20, 2017 @ 6:23 am

ACTIVE PATTERN: A complex severe weather situation is setting up for Alabama over the weekend, but today will be fairly quiet. Morning clouds will give way to some afternoon sunshine, just a small risk of a shower, and afternoon temperatures reach the mid 70s, right around record levels for mid to late January in Alabama.

There will be three windows for severe storms across Alabama over the next 2 days. Let’s take them one at a time.

ROUND ONE: The first chance of severe storms will come from roughly 3:00 a.m. until 9:00 a.m. tomorrow as a deep upper trough gets closer with strong wind fields, deep shear, and unstable air. SPC has parts of West and Southwest Alabama in the standard “slight” risk of severe storms, with a “marginal” risk northeast to Birmingham. Understand this “Day One” outlook runs through 6:00 a.m. CT tomorrow, and this is for the overnight storms we expect late tonight, after midnight…

ROUND TWO: There should be a lull in storm activity across the state during the midday hours tomorrow, allowing temperatures to rise into the low 70s, with increasing instability values. A few scattered storms could form tomorrow afternoon and evening, generally in the 3 p.m. to 9 p.m. time frame. This is a much more conditional threat; some of the good high resolution models show no development at all. But, considering the thermodynamic fields, we sure can’t rule out a few scattered severe storms in this window. In their “Day Two” outlook, SPC has an “enhanced risk” up for parts of West Alabama, and the standard “slight” risk identified for the rest of the state. Keep in mind this outlook runs from 6:00 a.m. tomorrow through 6:00 a.m. Sunday…

ROUND THREE: The final window for severe storms will come from about 3:00 a.m. through 12:00 noon Sunday, when the main upper low moves in from the west. Then, by Sunday afternoon, the main severe weather risk shifts down into Southwest Alabama, where SPC has the standard “slight” risk up on the “Day Three” outlook…

So, bottom line is that there could be multiple rounds of strong to severe storms over the weekend, but there will also be some good breaks in the rain.

THREATS: During each window over the weekend, storms could produce large hail, damaging winds, and a few tornadoes.

RAIN: Additional rain amounts of 1-3 inches are likely; major flooding issues are not expected.

CALL TO ACTION: Be sure you have a way of hearing severe weather watches and warnings. At home, you need a properly programmed NOAA Weather Radio with a battery backup. On your phone, for warnings we recommend WeatherRadio by WDT. You can watch our live severe weather coverage on the free ABC 33/40 app. Here are the links…

ABC 33/40 iOS version for iPhones and iPads

ABC 33/40 Android version for Android phones and tablets

Review your action plan in case a tornado warning polygon includes your home. Get in a small room, on the lowest floor, away from windows, and near the center of the house. You do NOT have to be underground. Never be in a car or mobile home.

NEXT WEEK: Monday will be cloudy, windy, and much cooler with some lingering light rain, mainly during the morning. The high will be in the 50-55 degree range. Even colder air arrives later in the week with highs dropping into the 40s. See the Weather Xtreme video for maps, graphics, and more details.

As always, watch me for the full weather story on ABC 33/40 News this evening at 4, 5, 6, and 10:00!

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus
Instagram
Snapchat: spannwx

I have a weather program this morning at Hillview Elementary School in Forestdale… be looking for the next Weather Xtreme video here by 4:00 this afternoon. Enjoy the day!

Rain/Storms Tonight; More Storms Saturday

| January 19, 2017 @ 4:11 pm

**No Weather Xtreme video this afternoon due to travel; I am writing this from the Tampa Airport… will be back later tonight**

RADAR CHECK: A large mass of rain and storms continues to move across Alabama; some of the heaviest rain late this afternoon is close to I-65…

The lack of instability should prevent any severe weather issues across North Alabama tonight, but severe storms are possible over the southern half of Alabama…

An isolated tornado is not totally out of the question this evening.

Some flooding is possible in low lying areas tonight, and rain amounts of 1-2″ are likely. The rain tapers off soon after midnight.

TOMORROW: A decent part of the day tomorrow will be dry; morning clouds should give way to some afternoon sun, and the high will be in the 70-73 degree range.

WEEKEND SEVERE STORMS: A complex pattern will set up across the Deep South with a deep upper trough just to the west with strong wind fields working with unstable air and deep layer shear. The first batch of storms seems likely Saturday morning… sometime between 5:00 a.m. and 12:00 noon… based on the high resolution NAM model.

SPC has the standard “slight risk” of severe weather defined for the southern two-thirds of the state Saturday.

The air becomes very unstable Saturday afternoon, and another round of strong to severe storms is possible during the late afternoon and nighttime hours, but model output is not consistent, and it remains to be seen if the best severe weather parameters will align at that point. We need to get past tonight’s storms to see the state of the atmosphere, and we will be able to give you specific details on the timing and magnitude of the weekend severe weather threat. It is simply too early to call on the potential event Saturday afternoon and Saturday night.

Storms could very well linger into Sunday morning, but the best risk of storms will shift east of Alabama by mid to late afternoon.

NEXT WEEK: Monday will be cloudy, breezy, and much cooler with some light rain at times; the high will be in the low to mid 50s. Then, even colder air should arrive toward the end of the week.

As always, watch me for the full weather story on ABC 33/40 News this evening at 4, 5, 6, and 10:00!

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus
Instagram
Snapchat: spannwx

I will be back in Alabama late tonight, and the next Weather Xtreme video will be posted here by 7:00 a.m. tomorrow…

Stormy Weather Pattern Through The Weekend

| January 19, 2017 @ 5:25 am

ACTIVE JANUARY WEATHER: We will be dealing with multiple rounds of rain and storms across Alabama through the weekend, with some potential for severe weather along the way.

TODAY/TONIGHT: SPC has parts of Central and South Alabama in a “marginal” risk for severe storms over the next 24 hours…

Rain is already falling over parts of the state this morning, and as an upper trough gets closer, rain and storms will be more widespread this afternoon and tonight. With this widespread rain, instability values will be limited, and with forecast soundings looking rather saturated, the overall severe weather threat seems pretty limited.

TIMING: Main window for the stronger storms will come from 3:00 this afternoon through about 12:00 midnight.

THREATS: Some of the heavier storms could produce gusty winds and small hail. The chance of a small tornado is pretty small, but not zero.

RAIN: Data from the RPM model suggests we could very well see some spots getting over 2 inches of rain over the next 24 hours, and if this verifies we could very well have some localized flash flooding problems. This looks to be more of a heavy rain event as opposed to a severe weather event.

Be sure you can hear severe weather warnings in the event they are needed later today and tonight.

TOMORROW AND THE WEEKEND: A complex severe weather pattern is setting up for Alabama, and we really need to get past the round of storms today and tonight before we can really be confident on forecasting timing of the various rounds of storms, and the overall magnitude of the event.

A deep upper trough with strong wind fields will approach from the west, and with high instability values, deep layer shear, and steep lapse rates, we will all have to pay close attention to the weather late tomorrow through Sunday morning. This is the current thinking on the timing…

ROUND ONE: The first round of severe storms is possible from about 9:00 p.m. tomorrow through 9:00 a.m. Saturday, generally over the southern half of the state. SPC has Southwest Alabama in the standard “slight risk”, with a “marginal risk” up to Tuscaloosa and Birmingham…

ROUND TWO: The air becomes very unstable by Saturday afternoon, and a few scattered severe storms are possible from about 2:00 p.m. until 8:00 p.m. Saturday over the state, including North Alabama. This round is a little “iffy” with the best dynamics a little to the west; much will depend on how the “round one” event impacts the airmass over the state.

ROUND THREE: A final round is likely from about 12:00 midnight Saturday night through 9:00 a.m. Sunday; this is when the best dynamic forcing will be in place.

SPC has most of Alabama in the standard “slight risk” for Saturday, Saturday night, and early Sunday morning (the Day 3 outlook runs from 6:00 a.m. Saturday to 6:00 a.m. Sunday)…

All modes of severe weather will be possible with the weekend storms, including damaging straight line winds, hail, and tornadoes. We will be much more specific about the threat tomorrow morning, but just understand you will need to pay close attention to the weather over the weekend.

NEXT WEEK: Monday will be windy and cooler with clouds and some lingering light rain; the high will drop into the 50s. And, even colder air arrives later in the week with highs dropping into the 40s. See the Weather Xtreme video for maps, graphics, and more details.

As always, watch me for the full weather story on ABC 33/40 News this evening at 4, 5, 6, and 10:00!

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus
Instagram
Snapchat: spannwx

I am in Tampa this morning for a company meeting, but will return later today. Most likely I won’t be able to produce a video this afternoon, but we will have forecast notes and running updates on the thunderstorm situation. Keep a close eye on the blog during this active weather, and enjoy the day!

Storms Tonight; Winter Issues Late This Week?

| January 2, 2017 @ 2:51 pm

RADAR CHECK: As expected, this has been a busy thunderstorm day across Alabama. Rain and storms continue this afternoon with the heaviest rain over East, Central, and Southwest Alabama. A flash flood emergency is in effect for Jackson, in Clarke County, where some roads have been washed out and travel is highly discouraged…

The highest instability values are over South Alabama; a tornado watch continues until 8:00 p.m. for all of the Mobile National Weather Service County Warning Area. A number of severe thunderstorm warnings are in effect for Southwest Alabama, and a tornado warning was just issued for South Baldwin County as I write this at 2:30 p.m…. a possible tornado was near Gulf Shores, moving in the general direction of Pensacola.

Another tornado warning has been issued for Crenshaw County, in South Alabama.

Also, a line of severe storms over Central and South Mississippi will move into Alabama within the next few hours, these storms will be capable of producing hail, damaging winds, and a few tornadoes. SPC maintains an “enhanced” severe weather threat for much of South Alabama, with the standard “slight risk” well into North Alabama…

Highest threat of a tornado will be over the “enhanced risk” area along and south of U.S. 80, but one can’t be ruled out over North/Central Alabama as well. Remember, it doesn’t take much instability for severe storms to develop in the cold season. The risk of severe weather continues for North/Central Alabama through about midnight, severe weather could linger past midnight over Southeast Alabama.

Be sure you can hear severe weather watches and warnings if they are needed tonight.

BIG TIME RAIN: A number of locations across Central Alabama are now reporting storm totals of 3 to 5 inches. While we have had some localized flooding problems, this is a very beneficial rain event for a state in an exceptional drought.

MID-WEEK: Lingering showers will end early tomorrow; the day will be mostly cloudy and mild with a high in the low 70s. Then, the weather turns sharply cooler Wednesday with a high closer to 50, and Arctic air settles in here Thursday… many locations north of Birmingham could hold in the 30s all day with a partly sunny sky.

WINTER WEATHER FUN AND GAMES? Snow lovers almost passed out when they saw the new 12Z run of the GFS, which was very aggressive with snow amounts over North Alabama late Friday night and Saturday, but they doesn’t seem plausible in this pattern, and the more reliable ECMWF (European) solution does show the chance of snow for North Alabama, but it would be mostly Friday afternoon and Friday night, with much lighter amounts… mostly 1 inch or less.

We need to get through tonight’s round of storms before we can really focus on the potential wintry precipitation… I will have a detailed “first forecast” early tomorrow morning here on the blog. Just be aware of the potential of winter weather impact across North Alabama Friday, Friday night, or maybe even part of the day Saturday. And check the early morning discussion tomorrow.

NEXT WEEK: Dry for the first half of the week with a slow warming trend. Take some time and watch the Weather Xtreme video for all the maps, graphics, and more details that go with this discussion.

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40. FYI we will produce this week’s show tomorrow night at 8:30p CT.

CONNECT: You can find me on all of the major social networks…

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Look for the next Weather Xtreme video here by 7:00 a.m. tomorrow… and stay tuned to the blog for updates tonight…

A Word About The Late Week Winter Mischief

| January 2, 2017 @ 10:52 am

Seeing lots of buzz about this across social media, and while I addressed it on the discussion early this morning, I wanted to make a few quick points at midday.

The new GFS run (12Z) has come in very aggressive with the idea of snow for North Alabama Saturday. Please understand, the map below is NOT a forecast, but just model output.

The latest run (00Z) of the reliable European model was not as aggressive, with just light snow amounts for North Alabama Friday night and Saturday morning. We will get the new 12Z Euro run by 12:30-1:00 p.m. CT today.

It is simply impossible to provide an accurate forecast of the potential winter event now; we need to get past today’s turbulent weather, and look at new data late tonight before we make a first detailed forecast tomorrow morning. For now, there is no reason to cancel anything! Just, just be aware of the possibility, and check the blog very early tomorrow morning (I will probably update this winter outlook later today after the new Euro arrives).

Stay tuned, and don’t forget we have an active severe weather threat going on through tonight! Here is the new SPC severe weather outlook through tonight.. highest tornado threat is over South Alabama, but one or two can’t be ruled out as far north as U.S. 278…

For North/Central Alabama, the core severe weather threat comes from about 4:00 p.m. to 12:00 midnight. The risk lingers after midnight for Southeast Alabama.

Severe Storms Possible Later Today/Tonight

| January 2, 2017 @ 6:34 am

Welcome to the New Year… and the weather folks will be very busy over the next seven days with severe weather potential today, and a chance of winter mischief as the weekend begins. But, the clear focus today has to be on the thunderstorm situation for the next 18-24 hours.

ON THE MAPS: A surface low is developing west of the state, supported by an upper trough lifting out of Texas. From the low, a warm front extends eastward through Central Alabama. This warm front will slowly lift northward today, bringing high dew points and unstable air to the state, and setting the stage for strong to severe thunderstorms this afternoon and tonight.

SPC maintains an “enhanced risk” of severe storms south of a line from Eutaw to Montgomery to Ozark… the standard “slight risk” covers the rest of the state, expect the northeast corner…

TIMING: Severe storms could break out as early as this afternoon, especially over the western counties of the state, but it seems like the core threat will come from 4pm until 12 midnight for North/Central Alabama. The risk of severe storms will linger past midnight over Southeast Alabama.

THREATS: The main risk of North Alabama will come from gusty straight line winds and hail, although an isolated tornado can’t be ruled out. But, the core tornado threat will be in the “enhanced risk” area of West and South Alabama tonight, where a better combination of instability and shear will be found. The updraft helicity product (via the high resolution NAM model) shows areas where rotating updrafts are more likely, and accordingly a higher tornado risk…

The updraft helicity product has performed well in other severe weather episodes in Alabama in recent years.

RAIN: Rain amounts of 1-2 inches are likely over the next 24 hours, with potential for more in spots. A flash flood watch is in effect for about the southern quarter of Alabama.

CALL TO ACTION: Today is a holiday for most, meaning many families will be traveling and not in their usual place on a Monday. So, be sure you have a way of hearing severe weather watches and warnings. At home, you need a properly programmed NOAA Weather Radio with a battery backup. On your phone, for warnings we recommend WeatherRadio by WDT. You can watch our live severe weather coverage on the free ABC 33/40 app. Here are the links…

ABC 33/40 iOS version for iPhones and iPads

ABC 33/40 Android version for Android phones and tablets

Review your action plan in case a tornado warning polygon includes your home. Get in a small room, on the lowest floor, away from windows, and near the center of the house. You do NOT have to be underground. Never be in a car or mobile home.

TOMORROW THROUGH THURSDAY: Rain ends very early tomorrow, but clouds will linger much of the day with temperatures in the 60s. Colder air invades Alabama Wednesday; looks like we hold in the 40s most of the day with a chilly north wind. And, by Thursday, as Arctic air settles into the state we will have a hard time getting out of the 30s with a mix of sun and clouds.

POTENTIAL WINTER MISCHIEF: Let me say up front we will have little confidence in a forecast solution for Friday/Saturday until we get past the event today. But, global models (both the GFS and the European) are suggesting potential for wintry precipitation across North Alabama at some point Friday night or Saturday. Snow lovers will love the latest GFS run, which is very aggressive, but the European seems to be more realistic at this point. And, using the ensemble approach, the mean is printing just under one inch of snow for Birmingham Friday night and early Saturday morning (green bars on the graph below)…

Just be aware that winter weather could impact the northern third of Alabama Friday night into at least part of the day Saturday; we will be able to be much more specific tomorrow. If you want to see all the maps and more details, watch the Weather Xtreme video.

Sunday looks cold and dry, followed by a warming trend early next week.

WEATHER BRAINS: Don’t forget you can listen to our weekly 90 minute netcast anytime on the web, or on iTunes. This is the show all about weather featuring many familiar voices, including our meteorologists here at ABC 33/40.

CONNECT: You can find me on all of the major social networks…

Facebook
Twitter
Google Plus
Instagram

We will have frequent updates throughout the day here on the blog… so check it often. If weather allows I will post a new Weather Xtrme video by 4:00 this afternoon; enjoy the day!

Three Weather Issues Ahead

| December 31, 2016 @ 4:15 am

Here is a quick look at the three issues facing Alabama over the next week…

WEEKEND RAIN: A good rain event will unfold this weekend with rising moisture levels, isentropic lift, and an approaching wave aloft.

As you can see, the heaviest rain should fall over South Alabama, where the NWS Mobile has issued a flash flood watch for seven Alabama counties, and Escambia County in Florida (including Pensacola)…

There will be breaks in the rain, but this looks like a very wet New Years weekend for most of Alabama.

SEVERE STORM POTENTIAL MONDAY INTO EARLY TUESDAY: Warm, unstable air will move northward during the day Monday ahead of another wave to the west, and by Monday afternoon dewpoints will be in the 60s well into North Alabama. This will make the air unstable, and set the stage for the chance of strong to severe storms. SPC has most of the state in a “marginal” severe weather risk, with a more significant “slight” risk over far West and Southwest Alabama.

Just too early to resolve the mesoscale details that will determine the severity of the threat for now, but these cold season systems can be very tricky to deal with. Looks like a classic “low CAPE, high shear” event we see this time of the year. Limited instability, but good veering of the wind with altitude. Looks like strong to severe storms could be possible from Monday afternoon well into Monday night and early Tuesday morning.

WINTER MISCHIEF LATE IN THE WEEK? Much colder, Arctic air will settle into Alabama Thursday and Friday, and with a broad southwest flow aloft with potential for embedded waves, that sets the stage for some potential for wintry precipitation somewhere across the southern U.S.

As usual, there is complete model madness for now. Best way to deal with this is to use the ensemble approach; this is model output using multiple runs (or members), with each using a slightly different set of initialization conditions. The collection of different runs from the series of initialization “tweaks” is called an ensemble.

Output from the GEFS (global ensemble forecast system with 21 members) still suggests some potential for wintry precipitation (snow, sleet, or freezing rain) across the southern U.S. in the January 5-7 time frame…

There is absolutely no way to resolve the details on this; some in this zone could very well see some sleet, freezing rain, or snow, but others will see just a cold rain, and some will get nothing.

Why share the idea at all? Because we are within 7 days of the event, where there is some forecast skill. And, it is our job to give you the range of possibilities out to seven days. We really need to get past the severe weather threat Monday night before we can have a good grasp on this; just something to watch for now.

As always, keep an eye on the blog for details on these three events…

Wild Weekend Weather

| December 17, 2016 @ 6:51 am

Here is a closer look at the issues facing Alabama this weekend…

SEVERE STORMS POSSIBLE OVER NORTHWEST ALABAMA TONIGHT: Temperatures today will warm into the low 70s with a strong south wind, setting the stage for the potential for strong to severe storms over parts of the state late tonight/early tomorrow…

PLACEMENT: As you can see from the SPC outlook, the standard “slight risk” of severe weather has been defined for the northwest corner of Alabama, and this is where the primary threat will be. This includes Muscle Shoals, Moulton, Russellville, Hamilton, Winfield, and Vernon. A “marginal risk” includes Birmingham and Tuscaloosa… no severe weather is expected over East Alabama.

TIMING: It now looks like the main threat for severe storms across Northwest Alabama will come from about 12:00 midnight through 4:00 a.m.

THREATS: The main issue will be strong straight line winds, although a few isolated tornadoes could form within the line of storms in this “low CAPE, high shear” environment. It is unlikely that discrete storms form ahead of the line, and generally any tornadoes that form in this linear setup are smaller and don’t last long. But still, you have to be vigilant and pay close attention to warnings if they are needed. When it comes to thunderstorms, “expected the unexpected”…

On the positive side, rain amounts of 1-2 inches are likely… which is badly needed here.

SUNDAY TEMPERATURE CRASH: At 6:00 CT Sunday, an Arctic front should be close to a line from Anniston to Alabaster to Thomasville…

North Alabama will hold in the 30s all day, and south of the front, some will wake up with temperatures in the mid to upper 60s, but they fall quickly through the 50s and 40s, and into the 30s. It will be a very cold December day.

WINTRY MIX? As the Arctic air settles southward, there is a chance that freezing rain and some sleet could develop on the back side of the precipitation mass over North Alabama Sunday morning…

With temperatures today rising into the low 70s, this means the infrastructure will be warm, limiting the overall impact, but a few icy spots are possible on bridges over the northern third of Alabama tomorrow morning.

Sometimes computer models don’t handle incoming Arctic air like this very well; all of Minnesota will be in the -20F to -30F range early tomorrow morning; this is a brutally cold airmass up in the source region. For now this doesn’t look like an especially high impact event for Alabama, but keep an eye on forecast developments over the next 24 hours if you plan on driving tomorrow morning across North Alabama.

A snow flake or two is also possible as the precipitation ends and the cold air gets deeper.

We will have frequent updates on the blog… watch for the new posts over the weekend.

Strong/Severe Storms Tomorrow Night

| December 16, 2016 @ 3:27 pm

WILD WEEKEND WEATHER CHANGES: Hang on to your hat for some very fast paced weather changes over the next 72 hours… you might consider taking some time to watch the Weather Xtreme video for all of the maps and graphics that go with this post.

TOMORROW: We zoom into the low 70s tomorrow afternoon, almost 50 degrees warmer than the lows we experienced this morning. The day will be cloudy, a gusty south wind will develop, and showers are likely. The most widespread rain tomorrow will be along and north of I-20 (along and north of a line from Tuscaloosa to Birmingham to Anniston).

SEVERE STORMS POSSIBLE TOMORROW NIGHT: SPC maintains the standard “slight risk” of severe storms for far Northwest Alabama tomorrow night, from Muscle Shoals down to Reform, with a “marginal risk” as far east as Gadsden, Calera, and Thomasville…

Dewpoints will surge into the mid 60s tomorrow night, and surface based CAPE values will rise to 500 j/kg in spots over West Alabama, meaning the air is unstable ahead of an approaching Arctic surface front.

The main window for severe storms will come from 10:00 p.m. tomorrow through 4:00 a.m. Sunday, and the highest risk will be west of I-65.

The core threat will come from strong straight line winds, but helicity values suggest an isolated tornado will be possible, especially in the “slight risk” area.

Just be sure you are in a position to hear severe weather warnings tomorrow night and very early Sunday morning if they are needed. On the positive side, rain amounts of 1-2 inches are likely.

BACK INTO THE DEEP FREEZE SUNDAY: The Arctic front should be south of Birmingham by 6:00 a.m. Sunday… temperatures over North Alabama will hold in the 30s all day with a brisk north wind. To the south, temperatures will fall from the mid to upper 60s into the 40s and 30s later in the day.

FREEZING RAIN/SLEET FOR FAR NORTH ALABAMA? As the rain ends and cold air rushes into the state, there is a chance could see a little freezing rain or sleet on the back side of the precipitation Sunday. Little if any impact is expected, however… if there is any ice accumulation, the greatest chance will be north of the Tennessee River over far North Alabama and up into Tennessee. If you are traveling north Sunday just pay attention to weather conditions.

NEXT WEEK AND BEYOND: Global models are now suggesting the week will be cool and dry with seasonal temperatures. For the Christmas weekend, looks like rain will be possible just west of Alabama. And, sorry snow fans, no evidence of any chance of a “White Christmas” here in Alabama this year.

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I enjoyed seeing the students at Fairview High School in Cullman County today… be looking for them on the Pepsi KIDCAM today at 5:00 on ABC 33/40 News! My next Weather Xtreme video will be posted bright and early Monday morning by 7:00… Brian Peters will have the video updates tomorrow and Sunday. Enjoy the weekend!