Severe Weather Outbreak for the Northeast and Midwest

Originally posted on ZoomRadar

A severe weather outbreak will begin today and continue through tomorrow night across many parts of the Midwest and the Northeast. While some of the details as far as exact locations and timing go are still somewhat unknown, it is clear that by Friday morning, many will likely be cleaning up from storm damage over the past two days. This is because of unstable air which will be in place behind a warm front but in front of a cold front which will push through these portions of the country over the next two days.

First let’s concentrate on what is going on right now and into tonight. Below is the current Day 1 Outlook from the SPC showing a large area highlighted under a slight risk of severe thunderstorms across the upper Midwest and into parts of western New York. The main threat will be damaging winds from these storms but some large hail and a couple of isolated tornadoes cannot be ruled out.

Here is the Day 1 SPC Outlook showing the wind damage probabilities for this evening and tonight. A 30% chance of severe wind within 25 miles of a point is expected to occur from areas in southeastern Wisconsin east toward central Michigan. In fact, most of this area is also under a 10% or greater probability of seeing significant wind gusts in excess of 65 knots.

The threat for damaging winds will mainly occur due to straight-line winds associated with lines of thunderstorms. This is the scenario that the current 18Z NAM model run depicts as well. This line or lines of storms should fire up this evening and continue into the overnight hours. Below is the 18Z NAM run showing what the reflectivity may look like this evening around sunset.

A line of storms may be most intense right across and around that 30% area the SPC highlighted for wind damage this evening and tonight. Taking a look at the modeled CAPE and EHI values, we also see that the storms will have plenty of instability to work with.

Storms are expected to continue through the overnight hours and into tomorrow morning, weakening some in the early morning hours. However, a line or lines of storms will refire up tomorrow most likely around midday and continue to track off to the east. Here is a look at what the 18Z NAM model is thinking right now as far as what the reflectivity may look like. The top image shows the reflectivity around midday into the early afternoon whereas the bottom image shows how it may appear in the late afternoon.

Once again, these storms will have plenty of instability with CAPE values approaching and exceeding 3000 J/kg according to the 18Z NAM model.

EHI values will also be good in some areas meaning that if any supercells can form out in front of the main line of storms, there could be a chance for a couple tornadoes.

For these reasons as well as the great upper air support that these storms will be dealing with, the SPC has issued a moderate risk for some areas in their Day 2 Outlook. These areas are the areas highlighted in purple, indicating a 45% chance of severe weather within 25 miles of a point, as well as a 10% or greater probability of significant severe weather within 25 miles of a point.

A large area is looking at a slight chance of severe weather tomorrow but the areas at the greatest risk will be from southern Illinois into Indiana, Ohio, Pennsylvania, New Jersey, New York, southern Vermont and New Hampshire, Massachusetts, Rhode Island, and Connecticut. Residents of these areas should prepare for the potential of straight-line wind damage, as this will be the main threat tomorrow and tomorrow night. If the line of storms becomes strong enough, and this is the current thinking, we could be looking at a long lived derecho which could produce damage similar to the one that affected areas of the Midwest and Mid-Atlantic on June 29th of this year.

The threat could be very extreme in some areas tomorrow so stay alert to the latest weather conditions and remember to seek shelter in advance of these storms.

Historic Heat and Drought

Originally posted on ZoomRadar

If you could ask people throughout the contiguous United States what two words they would use to describe the weather conditions this spring and so far this summer, I would imagine the answers would run along the lines of hot and dry. This has been the case for most areas in the lower 48 states so far this year, though it is important to note that this is not true for everywhere in the lower 48. In fact, some areas have seen above normal precipitation so far this year, including areas of central Texas, most of Maine, as well as many areas of the Pacific Northwest, northern Rockies, and northern Plains.

The graphic below shows how temperatures compared to the 1981 to 2010 average across the lower 48 last month. Despite the month officially rating as the fourth warmest June on record globally, with records dating back to 1880, some areas of the U.S. saw below normal temperatures during this time period, denoted in blues below.



But like I stated previously, most of the nation has been experiencing heat and little rainfall. June marked the 328th continuous month with temperatures above the 20th century average according to NOAA. The United States seems to be taking the brunt of the heat as well. Temperatures globally in June were nearly two degrees Fahrenheit above average on the world’s landmasses and have been 1.57 degrees above average so far this year. But in the U.S., temperatures have been averaging 4.5 degrees above normal so far this year, now that is some heat!

And as if the heat was not enough to worry about, drought conditions have continued to worsen across a vast portion of the lower 48 states. Drought conditions are depicted in the map below as of July 10th and have likely continued to worse across many portions.

In terms of the area affected by this drought, this is now officially the worse drought since the 1950s. About 61% of the continental U.S. currently qualifies as being in some level of a drought according to the U.S. Drought Monitor. The Palmer Drought Index, an older and less detailed index, reports that 56% of the United States is currently under drought conditions. The last time drought covered more area in the lower 48 states was in December 1956.

This current drought does not compare to past droughts in duration yet, but with no major relief in the near future, conditions may continue for some time. Below is the NAM model depicting how much precipitation may fall over the next 84 hours. While some relief may fall over this time period, it will not affect all areas and will not be enough to eliminate the precipitation deficit, though any help will be very welcomed in these areas.

Below is the precipitation across the United States over the past 60 days when compared to normal, showing many areas suffering from precipitation deficits.

All of this heat and lack of precipitation has unfortunately led to many issues across the nation and will continue to do so. Heat related deaths have occurred in many states and many more have likely suffered from heat related illnesses. Additionally, dry conditions have wreaked havoc on the nation’s corn crop, with the U.S. Department of Agriculture now reporting that 38% of the crop is in poor or very poor condition. Problems have also arisen in the form of wildfires due to the dry conditions. Below is a map showing the current large wildfires across the United States.

The summer will likely continue with more hot and dry conditions so it is important to take precautions to protect your life and property. Be sure to stay hydrated, take breaks from the sun, monitor any fires you start closely, and of course stay up to date on the latest weather information.

The Past, Present, and Future of Debby

Originally posted on ZoomRadar

Tropical Storm Debby, now Tropical Depression Debby, has weakened some since its formation and slight strengthening in the Gulf of Mexico. A tropical cyclone that seemed like it could end up anywhere from Florida to Texas according to weather models early on, ended up striking Florida in a very similar scenario to what the GFS model had been predicting for days. Below is the current location of the system along with the expected track over the next five days.

At this time the thinking is that Debby may strengthen again into a weak Tropical Storm, as shown in the maximum wind speed probabilities table below, but should remain off the east coast of the United States. This means that the largest threats to the United States from here on out from Debby should just be some light rain as it exits the Southeast as well as some larger waves along the East Coast.

Despite never gaining hurricane strength, Debby did pack a punch for those affected by her. Tropical storm force winds occurred over a large area of the Florida Peninsula as well as along the Gulf Coast and areas of inland Florida all the way south to the Fort Myers area. Fortunately, most of this wind was below the speed needed to create more widespread damage though areas of isolated wind damage were reported, especially during the stronger thunderstorm bands which passed through the state.

These thunderstorm bands were responsible for more than just wind damage however, some of the strongest storms spawned tornadoes which resulted in one of the system’s two blamed fatalities thus far, the other resulting from a drowning. Below are the images depicting the severe weather reports from the system starting on June 23rd and proceeding through the 26th.

The 23rd resulted in 5 tornado reports, all in Florida due to intense bands of thunderstorms coming ashore and this scenario continued on the 24th, resulting in 20 more tornado reports across Florida. The 24th ended up being the most violent day from Debby in terms of severe weather as a few areas reported damaging wind gusts from thunderstorms as well. Below is an image showing Doppler Radar detected rotation with red lines across the state of Florida on the 24th along with the reports received and the location of the one fatality. It was a very active day for tornado warnings across the southern and central parts of the state as almost all of these rotation tracks prompted a tornado warning.

Over the past two days, the system has pushed across Florida, resulting in more heavy rain than damaging thunderstorms, though a few still existed. However, the tornado threat was over, as the right front quadrant of the storm had moved over the Atlantic waters more.

The main problem from Debby was her rain. Sitting nearly stalled out over the warm water of the Gulf of Mexico for a couple days, rain was continually dumped across parts of Florida. Below is the total precipitation over the past 7 days ending this morning across the Southeast.

Amounts in excess of five inches were pretty common across the central and northern parts of Florida with some of the heavier rain even affecting parts of southern Georgia as well. The hardest hit areas in terms of rainfall seemed to be around the Tampa region as well as the Crawfordville area east across the state into the Jacksonville region. Areas in these parts picked up greater than 10 inches of rainfall with some isolated areas probably picking up in excess of 20 inches of rainfall! This has resulted in flooding issues across many parts of Florida and the issuance of Flood Warnings. Gainesville, FL recorded their second highest three day precipitation amount at 12.02 inches and broke its all time record for most rain in the month of June with a total of 16.34 inches so far.

Below are some of the images showing the effects of Debby. All credit for these images goes to the USA Today and all of their storm images can be viewed here.

Tropical Update: Chris is no concern but what about what could be Debby?

Originally posted on ZoomRadar

After an early start to the Atlantic hurricane season with two tropical storms in the month of May, activity came to a lull once the season officially kicked off on June 1st. Now that we are nearly three weeks into the season, things are becoming more active once again. Yesterday, the National Hurricane Center officially named the third topical storm of the Atlantic season, Chris. While many though Chris was destined to be a named storm which has yet to form in the Gulf, mother nature had other ideas. Tropical storm Chris was born way off the east coast and became the third earliest third tropical cyclone to form in the Atlantic. Only the years 1887 and 1959 had their third tropical cyclone from earlier.

Despite a current maximum sustained wind strength of 50 mph, the track of Chris keeps it away from land. Chris should continue moving east to northeast and after some potential strengthening today, should begin to weaken tomorrow and eventually die sometime this weekend.

While Tropical Storm Chris may not be of any concern to the United States, the concern for tropical development in the Gulf of Mexico may be. For some time now, the GFS model has been hinting at the potential for tropical development in the Gulf of Mexico sometime late this week. Now that this time is getting closer, the National Hurricane Center has begun to monitor this area and has highlighted it with a 20% chance of tropical development in the next 48 hours.

A low pressure trough is in place from the northwestern Caribbean Sea to southern Florida and has been producing widespread cloudiness along with showers and thunderstorms. The system is expected to continue moving slowly northwest into the southeast Gulf of Mexico over the next 48 hours where it should encounter conditions that will be more favorable for development. If the system does form it will become the fourth tropical cyclone of the 2012 Atlantic Hurricane Season and acquire the name Debby.

Below is the current 850 mb relative vorticity from the 12Z NAM model showing some weak vorticity across the southeastern Gulf of Mexico area this morning.

As this relative vorticity strengthens, as shown for the 12Z NAM model depicting 48 hours from this morning, tropical development will become more favorable across the Gulf of Mexico.

A big issue for strong development though will be the sea surface temperatures, shown below. While the temperatures themselves are warm enough for development, the highest sea surface temperatures will likely remain just to the west of the system as it makes its track toward the northwest.

If this system moves further west than expected, it may have a chance at strengthening more than anticipated at this moment. However, at this time the NAM model does not expect this to happen. Shown below are the 06Z NAM run and the 12Z NAM run showing what the surface winds and pressure of the system may look like on Saturday afternoon.

Both model runs believe the system will be just south of Louisiana with a central pressure just below 1008 mb. Winds would likely be topping out between 20 and 30 knots, leaving this system just shy of tropical storm strength. If this were to be the case, this system would be nothing more than a rainmaker for the Gulf Coast. Below is the precipitation forecast from the 12Z NAM model showing the total amount of precipitation it expects to fall from this morning until Saturday evening.

Now before ruling this system out as just as rainmaker, the GFS model continues to tell a different tale. The 12Z GFS model has this system moving in a similar track to the NAM model at first with the center of the system being a little ways south of Louisiana, shown below.

Now it is important to note that the NAM model may have a similar solution but due to its run only going out 84 hours, it is impossible to tell where it thinks this system may go. The GFS model does have the system being further south than NAM model though and that could be a reason for what the GFS model thinks may come next. Below is the 12Z GFS model showing what would be Tropical Storm Debby making landfall across central Florida on Monday night.

In this model run, it appears the central pressure would be around 994 mb with peak winds above 40 knots (46 mph). If this were the case, we could be looking at a strong tropical storm hitting Florida with some damaging winds, a tornado threat, and flooding rainfall. Below is the 96 hour precipitation forecast showing total precipitation from this morning until Sunday morning as depicted by the 12Z GFS model.

Before the storm would even make landfall, some areas along the Florida Gulf Coast could pick up well over 3 inches of rain with isolated amounts likely reaching 10 inches. The situation would only get worse as the system would cross Florida in this scenario and head north just off the shore of the East Coast. Shown below is the total precipitation expected by the 12Z GFS model run from Sunday morning until next Thursday morning.

At least another inch of rain will fall across many parts of central and southern Florida with some areas receiving in excess of six inches of precipitation during this time period, shown in white and gray. In fact, some isolated area could see above 10 inches of precipitation during this time period resulting in storm totals nearing 20 inches in the worst hit areas. If this were to come true, there could be widespread flooding issues across the state of Florida.

From here, as mentioned, Debby would head north and actually restrengthen. Below is the 12Z GFS model depicting the storm on next Wednesday morning just off the coast of the Northeast and Mid-Atlantic. The central pressure of the system may be all the way down to around 984 mb with winds in excess of 50 knots.

In this scenario, the system would continue to push northward and gradually weaken as it encountered land, potentially making landfall in Maine. If this were the case, heavy precipitation amount, shown in the precipitation map above, may result in some flooding and beach erosion may become a concern. Additionally, while winds should subside some before making landfall, high winds could still be an issue in coastal areas.

Keep an eye on this tropical system throughout the week as it does pose some potential to become of the first hurricane of the season if it can follow a path similar to what the GFS is thinking. Either way, this system will be bringing a lot of rain to wherever it strikes and people living along the Gulf Coast, especially the eastern half, should continue to monitor this system carefully over the next few days.

Dry Heat Continues Fire Issues in the Southwest

Originally posted on ZoomRadar

The heat is on across many parts of the Southwest prompting excessive heat warnings in some areas. Temperatures will sore to well above 100 today in parts of southwest California, Arizona, southern Nevada, and even across the High Plain region. Temperatures in excess of 110 to 115 degrees may be expected in some more isolated areas, shown below.

The heat will continue tomorrow too, shown below, though it will not be quite as hot as today in most spots across the Southwest. However, this does not mean the heat is coming to an end as the current weather models tend to show an extended period of heat affecting this region. It appears that summer is here and here to stay in the Southwest.

And as if the heat was not bad enough, it appears that the air will be quite dry as well. This dry air will only exasperate the current wildfire situation across the Southwest. There are currently multiple large fires burning across the Southwest area which is shown below.

In fact, some of the larger fires can even be seen on satellite today. Below is a visible satellite image from today showing two large fires in Colorado. One is the in the middle northern portion of the state and has already burnt nearly 60,000 acres resulting in the loss of 181 structures so far. That fire is currently only 45% contained. The other is a smaller fire in the middle of the state west of Colorado Springs. That fire has only burnt about 300 acres so far but it is 0% contained and threatens many structures in the area.

Many of these large fires are burning due to the lack of rain which has occurred in the Southwest this year so far. Below is an image depicting the year to date rainfall across the Southwest as a percentage of normal. As can be seen, a vast majority of the Southwest has seen below normal precipitation so far this year. The areas in reds have seen less than 25% of their typical precipitation thus far this year.

This year’s lack of rainfall across the Southwest, coupled with drought problems from last year, have resulted in continuing drought issues. Below is the latest U.S. Drought Monitor showing almost all of the Southwest at least being abnormally dry. Some areas in northwest Colorado, southeast New Mexico, and parts of Arizona are even experiencing extreme drought.

So far no areas have qualified for exceptional drought, which is good news. But, with monsoon season really still being about a month away and little rain expected in the future, these drought conditions will likely only continue to worsen. Below is the 12Z NAM model’s prediction for precipitation over the next 84 hours ending Thursday evening. Little, if any precipitation is expected over the Southwest during this time period.

The 12Z GFS model does show a better chance for precipitation across parts of Arizona, northern New Mexico, and Colorado for this weekend and early next week though. However, with such dry air in place, much of this precipitation may evaporate before it hits the ground. This could result in dry thunderstorms and could escalate the wildfire issue instead of helping it by creating new lightning sparked fires across the area.

Back to the near term though, dew points will be incredibly low today and tomorrow, shown below. Making matters worse, surface winds will be between 10 and 20 knots or higher for much of the Southwest.

This will result in a large area at risk for wildfires today. A critical area includes much of interior southern California, Nevada, southern Idaho, Utah, Wyoming, western Colorado, and northern Arizona. Other areas across southern Arizona, New Mexico and into eastern Colorado, while not at a critical risk, will still be dealing with ideal conditions for wildfire growth and development. By tomorrow, winds will subside some resulting in less of a risk of wildfires. That being said, a critical risk will still exist across northeast Utah, northwest Colorado, and southern Wyoming. Some risk may also exist across southern Arizona.

If you live or will be traveling to the Southwest anytime soon, please be aware of the heat and fire conditions that will undoubtedly be in place for much of this region. Hopefully some relief will occur this weekend into early next week for fire danger but do not expect it to be long lived.