Northwest Florida Weather (12-14-2016) - All Aboard the Roller Coaster!

Living in Northwest Florida, the wintertime is a roller coaster ride when it comes to the weather. Some days, it's warm enough to go to the beach. Others are days where you'd rather stay in bed with multiple blankets. Unfortunately, the next seven days feature days to satisfy both the beach days and the bed days (probably not all that great for colds either). However, a single seven-day forecast (or, in my case, two seven-day forecasts since I do both inland and coastal seven-days) just doesn't show you all the detail. They could, but they quickly become crowded. Thankfully, I am not having to include wintry precipitation in our forecast, so that makes my life (and your life) much easier. Below, I will show each of the seven days and give you a brief discussion about the forecast.

THURSDAY:

Thursday will feature colder temperatures than we have seen lately. We've been well into the 70s and even near 80 for a few days now, so 50s and 60s will be a shock to the system. Keep in mind, this is about 5 degrees below normal for this time of year. It will be a bit breezy, too, so that will make it feel a bit colder. At least it will be sunny, right?

Thursday night will be cold. Lows will be near freezing, and even below in some spots (I'm looking at you, Crestview). Coastal areas will escape the coldest temperatures, but will still be near 40. Clear skies, and winds will be calming down.

FRIDAY:

Friday is a day of change. Just as quickly as we went down, we go right back up. A few clouds will dot the sky on Friday, gradually increasing into the nighttime hours. Notice that the winds have shifted to out of the southeast, now, which helps bring in warmer temperatures. Highs on Friday will be near to slightly above normal with temperatures in the mid 60s.

The southeasterly wind will continue to bring in warmer temperatures through the night. We fall to our lows early in the night on Friday, so those upper 50s and lower 60s may occur closer to midnight, then gradually increase to the upper 60s/near 70 by Saturday morning. Clouds will increase through the night as well.

SATURDAY:

Saturday will be the warmest day in the forecast, with temperatures approaching record levels. The record high for Pensacola (the official climate reporting station in Northwest Florida) is 78. We'll be close, and we could even hit 80 in some inland areas, especially if a bit more sunshine pokes through the clouds. This is one of those days that could be a good beach day, barring the fact that the rip current risk will likely be moderate to high and water temperatures in the 60s. Skies will remain generally cloudy during the day, and winds will also pick up. There is only a 20% chance of a shower during the day.

Saturday night, rain chances increase ever so slightly, especially the farther west you are (areas such as Pensacola, Century, Jay, and Milton). Very warm overnight lows are expected with temperatures in the mid to upper 60s. Now, here is an interesting fact: those overnight lows are above the normal high for this time of year.

SUNDAY:

Sunday is yet another day of change. Rain and thunderstorms look likely. Right now, it's too early to give specifics on a severe weather threat, but we will have to continue monitoring. We will know more once we get closer to Sunday. However, the cold front is expected to pass through during the day, hence the winds shifting from southwest to north. The further west you are, the more likely your temperatures will fall during the afternoon. If you are further east, your temperatures will fall quite a bit during the evening as the cold front moves through. Either way, the highs marked here are averages for the area. The further west you are, highs may be in the upper 60s/lower 70s. The further east you are, highs may be in the mid to upper 70s.

For Sunday night, thunderstorms will end during the evening, but we could still have showers overnight. Lows will be nearly 20 degrees cooler than Saturday night with temperatures in the upper 40s to lower 50s. Winds will be rather breezy, ushering in the colder air.

MONDAY through WEDNESDAY:

The early part of next week is generally constant as far as weather goes. There is still a good chance of rain on Monday as leftover moisture just lingers over the area. It will be much cooler, so this is a day that you would want to stay in bed. Basically, it will truly feel like a Monday. Highs will only manage the mid to upper 50s. Rain chances gradually decrease Tuesday and Wednesday as temperatures start to warm back up. Highs by Wednesday will be in the mid 60s and lows will be in the 50s. Winds on Wednesday night will shift back out of the southeast ahead of potentially another system, but that's too far out to even think about speculating.

Remember, for more frequent updates, you can follow my social media sites:

Facebook | Twitter

Northwest Florida Weather (11/29/2016) - Another Severe Weather Threat

Before I begin this blog post, I'd like to extend my sincerest thoughts and prayers to those in Gatlinburg, Pigeon Forge, and surrounding areas that were affected by the wildfire. Extremely sad situation with loss of life. I'm thankful, as I'm sure many are, for the first responders' and emergency personnel's acting quickly as it could have been a lot worse.

Now, back to Northwest Florida weather information.

Well, frankly, last night ended up being a lack of rain for most areas. The good news is that we didn't have any severe weather in our area, but the bad news is that most areas didn't get much rain, if any. Why was that?

Well, last night, we were lacking instability, which some models were not picking up on. The line of storms was forecast to weaken as it moved further east, but the actual line weakened sooner than what models were thinking. Most of the better lift and instability was to our north and away from us in Northwest Florida.

So, what about tonight and tomorrow?

The Convective Outlook issued by the Storm Prediction Center (SPC). This map is valid through 6 AM CST Wednesday morning.

Parts of Northwest Florida are in the "Marginal Risk" of severe weather. This is a Level 1 out of 5, meaning we could get some isolated severe thunderstorms. But, what severe weather we might get would be closer to 6 AM Wednesday.

SPC's Convective Outlook for 6 AM Wednesday through 6 AM Thursday.

SPC has place all of Northwest Florida under a "Marginal Risk" for Wednesday. This again is a Level 1 out of 5. Isolated severe thunderstorms will be possible, with damaging winds being the main threat with any severe thunderstorms. Let's talk some meteorology!

Model sounding from the HRRR (High-Resolution Rapid Refresh) Model valid at 11 AM CST Wednesday at KVPS (Eglin AFB, FL). Focusing mostly on the left half of the image. The solid red line is the temperature profile through the atmosphere, the solid green line is the dew point profile. Pressure is labeled in millibars on the left, decreasing with height. Temperatures are labeled on the bottom in degrees Celsius. Multiple parameter are located at the bottom of the image. Image courtesy of pivotalweather.com and SHARPpy.

I personally think these model soundings are a meteorologist's best friend. There's just an abundance of information you can get from these. So, let's see what there is to see.

• Generally, there is atmosphere is abundantly moist, especially at/below 700 mb. There are two ways we can see this. First, the temperature and dew point lines are pretty close together. Second, the precipitable water (labeled PW in the parameters table) is around 1.67 inches, meaning the atmosphere is sufficiently moist. Note about the precipitable water: Basically, it's how much water would accumulate if all the moisture in the atmosphere above a point was wrung out. The moisture allows for cloud and precipitation development. Also, the more moist the atmosphere is, the higher possibility of heavy rainfall, and the rainfall can help transfer some higher winds aloft to the surface ("waterloading")
• Warm air advection through the lower portion of the atmosphere. This is a lifting mechanism. Warm air is less dense and warm air can rise.
• CAPE is high, meaning plentiful instability, allowing air to rise easily.
• Decent shear, which is favorable for thunderstorm development.
• Dry adiabatic layer from about 900 mb to the surface. (Dry adiabatic layer means that the temperature profile is parallel to the dry adiabatic lapse rate, denoted by the thin diagonal white lines going up and to the left. The dry adiabatic lapse rate is the rate at which the atmosphere cools as you proceed upward in the atmosphere if the atmosphere is not saturated.) This will allow winds to be transported downward more easily.

One note, the sounding algorithms do spit out a "possible hazard type" of tornado. I use this only as a worst case scenario. This should not be taken as there gospel truth.

So, the signals are good for at least thunderstorms, and maybe some severe storms. But there are a couple of caveats.

• Helicity is not all that impressive, meaning that there is not as much spin in the atmosphere. Thus, it does not lend itself to an atmosphere supportive of tornadoes. That's not to say it can't happen, but it's less likely.
• This model assumes that the temperature will make it to near 80 degrees at the surface. I'm not fully confident in that solution. I do think it will be warm, but I'm not sure about it being that warm. This affects CAPE, low level moisture, and that dry adiabatic layer.

Here is what the HRRR model (the same one the sounding is from) predicts the radar will look like:

HRRR predicted 1 km reflectivity valid from 8 PM CST Tuesday through 11 AM CST Wednesday.

The HRRR only goes out 18 hours. It shows a line of thunderstorms (potentially strong to severe) entering Northwest Florida around 9 AM (+/- 2 hours). But the general trend looks to be slow weakening as it moves further east.

So, again, this is just one run of one model. Just one tool in our toolbox. Let's take a look at one other model.

This is a model sounding from the NAM valid at 12 PM CST Wednesday. Same properties as the sounding above.

So, just like the HRRR, the NAM has abundant moisture, warm air advection, decent CAPE (for this time of year), and decent shear. Now, there are a few differences. It's not as warm at the surface, thus nearly eliminating the dry adiabatic layer. Speaking of which, it looks like the dry adiabatic layer is only from 975 mb to the surface, not nearly enough for easily transporting winds from aloft to the surface. But, there is more helicity than there was in the HRRR sounding, meaning more possibility for rotation. So, what does this mean?

With lower instability, we may not see as much thunderstorm development. With fewer thunderstorms to tap into that helicity, the threat of tornadoes is lower. There could still be damaging winds with stronger storms. But what does the predicted radar look like with the NAM?

NAM predicted radar valid from 9 PM CST Tuesday through 9 PM Wednesday.

The NAM does not have as much in the way of intense convection (meaning that it may not be predicting as much thunderstorm activity). The NAM also brings in the convection later than the HRRR, closer to 12 PM. But the general trend is the same, weakening as it moves further east.

So what does this all mean for your forecast? We will probably see more scattered showers around Northwest Florida tonight, not really expecting much in the way of thunderstorm activity tonight, but can't rule out an isolated storm. Severe weather is not expected tonight. Wednesday is our better chance of rain. Showers and thunderstorms look to move into Northwest Florida during the mid to late morning and move eastward. The general trend is for the line to weaken as it moves further east. An isolated severe thunderstorm or two cannot be ruled out with damaging winds being the main threats. Widespread severe weather is not expected in our area.

Northwest Florida Weather - Rain Brings Good News and Bad News

Total rainfall through midnight Wednesday night predicted by the NAM (North American Mesoscale) model.

There is a good chance of something we haven't seen much of in Northwest Florida for quite some time. Rain! While this likely won't be drought-busting rain, 0.5 to 1 inch is not out of the question during the next couple of days. And, besides, it's more rain than we've seen in quite some time. Unfortunately, there is a down side to this rain, and that's the possibility of severe weather.

The Convective Outlook from the Storm Prediction Center (SPC) showing the possibility of severe weather across the state of Florida. This map is valid until 6:00 AM CST Tuesday.

Yes, we have the potential of severe weather tonight (Monday night) into Tuesday morning here in northwest Florida. The Storm Prediction Center (SPC) has outlined areas generally west of Highway 331 (including Escambia, Santa Rosa, and Okaloosa Counties) in a "Marginal Risk" of severe weather, meaning that isolated severe thunderstorms are possible in that area. This risk is valid through 6 AM Tuesday morning. The environment isn't too supportive of severe weather for tonight, but some thunderstorms are in the forecast. Let's take a dive into a bit of meteorology.

from pivotalweather.com & SHARPpy. This is a model sounding from the HRRR (High-Resolution Rapid Refresh) model. The solid red line in the upper left diagram is the temperature profile through the atmosphere, and the solid green line is the dew point profile. The closer the lines are to each other, the more moist the atmosphere is. On the left, the pressure levels are labeled in millibars (mb) decreasing with height, and the temperatures are labeled on the bottom in degrees Celsius. Winds are labeled on the right hand side of the upper left diagram in knots.

This model sounding (from SHARPpy) shows what the HRRR thinks the atmosphere will look like at 3 AM CST at KVPS (Eglin AFB). Let's go through some things working in favor of severe weather tonight.

• Sufficient moisture at and below 700 mb.
• Strong winds around 850 mb (winds around 40-45 knots, 45-50 mph)
• Warm air advection
• Sufficient helicity
• Sufficient shear
• Decent instability

So, we pretty much checked off all of our severe weather ingredients. But, keep in mind, this is just one run of one model, and the atmosphere doesn't always behave like we want it to. Let me discuss a bit about models. Models ingest data before their run. The model already has its initial forecast planned out, then it uses the observations and data it ingests to adjust its forecast. The model can either adjust its forecast to come closer to the observation or reject the observation. The model rarely, if ever, accepts an observation as absolute truth. This already causes inherent error. Plus, observations aren't taken everywhere, especially upper air observations. Thus, we as meteorologists have to try to figure out if the model is performing well with interpreting and interpolating data. You can see where a lot can go wrong already, but this topic is for another time. Back to severe weather.

So, with one run of one model, it looks like severe weather is a decent possibility. One thing to note is that this sounding indicates a "possible hazard type" of tornado. I generally use the "possible hazard type" as the worst-case scenario of what could happen. Remember, that is also dependent on if there are storms around. Let's look at the same model run to see what it predicts as far as future radar.

Same run of the HRRR as the model sounding came from. This is the 1 km above ground level reflectivity forecast. Essentially, this is a future radar product. This is valid through 9 AM CST Tuesday morning.

The model shows a broken line of showers and thunderstorms moving through the Florida Panhandle early Tuesday morning. Now, notice that the line in general appears to weaken as it moves further east. So, if you're in Panama City or Marianna, your severe weather chance will be lower. Before we move on, let's look at one more just to show the uncertainty.

This is the 4 km NAM (North American Mesoscale) model valid through 9 AM CST Tuesday. Showing the same product as depicted in the HRRR model animation.

You can see, this model nearly completely dissipates the line of storms before getting here. This is why there's still quite a bit of uncertainty, even in the short term forecast.

Overall, I think our severe weather threat is low tonight and tomorrow morning. Gusty winds will be the main threat with the stronger storms tonight. I can't fully rule out an isolated tornado, but I think the better chance of that happening would be to our north and west.

Going into Tuesday and Wednesday, we still do have a risk of severe weather across northwest Florida. Here are the convective outlooks from the Storm Prediction Center.

SPC's convective outlook valid from 6 AM Tuesday through 6 AM Wednesday.

SPC's convective outlook valid from 6 AM Wednesday through 6 AM Thursday

The second threat of severe weather looks to be primarily Wednesday morning across northwest Florida. Again, damaging winds look to be the primary threat with severe thunderstorms. An additional blog post will be published on this possible severe weather threat tomorrow afternoon.

NW FL Weather (11/15/2016) - Sunny & Dry, But Turning Cooler

The forecast sounds like a broken record: sunny and dry. Drought conditions continue across Northwest Florida. In fact, much of Northwest Florida is under a "Moderate Drought" (except for a small sliver of northern Santa Rosa County where there is a "Severe Drought").

Current Drought Monitor for the State of Florida. Map courtesy of the National Drought Mitigation Center (NDMC), U.S. Department of Agriculture (USDA), and the National Oceanic and Atmospheric Administration (NOAA)

This map will be updated on Thursday. Without any rainfall in the next 7 days, our drought will continue to gradually worsen. The drought is taking a serious toll on soil moisture. Here is the Keetch-Byram Drought Index for Northwest Florida.

Current Keetch-Byram Drought Index from the Florida Forest Service. Used Blackwater and Chipola Forest District maps.

The Keetch-Byram Drought Index (KBDI) measures the amount of water in the top 32" of soil. It is assumed that the maximum amount of water in that top layer of soil is 8" of water. The index goes from 0 (absolutely wet) to 800 (absolutely dry). So, Okaloosa County is currently the driest county on average according to this index with a value of 666. This means that there is 6.66" of water missing from the soil. Unfortunately, with the dry soil, this helps provide fuel for wildfires.

Without rain in our forecast, we focus purely on the temperatures. As the cold front moves through Saturday morning, it will not bring a substantial rain chance (right now, less than 10%). But, the front does bring cooler, drier air.

Animation of the 18Z (12 PM CST) run of the GFS model showing mean sea-level pressure (black solid lines), 1000-500 mb thickness (red and blue dashed lines), and 6-hr. precipitation accumulation (shaded). Fronts drawn in by me.

The cold front will move through Northwest Florida on Saturday morning. Temperatures will be warmer the further east you are, but will fall once the front passes. Here are your 7-day forecasts for inland and coastal regions (updated since video above):

The National Weather Service in Mobile does note that Frost and/or Freeze Warnings may be required by Sunday night. Several areas could see their first frost and first freeze of the season. Interestingly, Crestview has already had their first freeze of this season (November 11):

Believe it or not, Crestview #FLwx dropped to 32° degrees this morning, making it the first freeze this season. pic.twitter.com/Nv5QB3Jm2p

— Cameron Young (@wx_cam) November 12, 2016

So, prepare for more dry weather. Cooler weather will make its way back down to the Gulf Coast by this weekend and early next week.