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    It’s not hard to see why it’s much hotter North than here, they have a dry layer of air at mid-levels providing ample sunshine while we have lots of moisture not only at the surface but in the mid-layers of the atmosphere providing more clouds and rain chances.  On top of that while our air mass is pure Gulf of Mexico tropical humidity, the air trajectories up North are tapping into some hot air from Texas and Oklahoma on a Southwest to NE air flow: FORECAST MAXIMUM HEAT INDEX LATE AFTERNOON NEXT COUPLE DAYS: But as I posted yesterday morning we ease back on the thermometer a little the next few days with the increased clouds and scattered thundershowers, then a major front next week brings relief from the abnormally high humidity we’ve had for weeks now.  See the frontal rain location Monday afternoon: Tuesday afternoon: The end of day Wednesday: FORECAST LOW TEMPERATURES WEDNESDAY/THURSDAY: Look at the change in dew point (surface moisture content of air) This weekend: FORECAST DEW POINTS THURSDAY MORNING: Certainly not dry air but much less humid to pair with lower temperatures. Look at total air moisture Tuesday: Compared to Thursday morning: Keep in the back of your mind that this time of year when a front gets into the South Atlantic and Gulf of Mexico a tropical system often develops on the old dying frontal boundary, something to watch next week and the week after. Nothing is shown by models yet.  For more follow me on Twitter @MellishMeterWSB.
  • A body was found inside a burning vehicle at a busy South Fulton intersection Thursday morning, police confirmed to AJC.com. South Fulton police and fire crews responded to the scene at the corner of Pleasant Hill Road and Old National Highway just after 2:30 a.m., according to police spokesman Lt. Derrick Rogers. “Investigators are working to identify the remains and will be investigating this incident as a possible homicide,” he said in a statement. Channel 2 Action News reported the body, believed to be that of a man, was burned so badly, he will have to be identified through dental records. Authorities towed the car away from the scene after putting wrapping paper around it with the body still inside, the news station reported.  The case remains under investigation. We’re working to learn more. — Please return to AJC.com for updates. In other news: 
  • We look to stay in a soupy “air you can wear” tropical air mass with hot afternoons and warm muggy nights: temperatures above normal day and night for at least the next 3 days. The big heat wave gripping most of the nation will shift out West next week.  High moisture air will be provided at times by the Bermuda High Pressure and at other times by Easterly Trade Waves off the Atlantic. That combo plus an upper-level trough of low pressure over us will provide a potentially unstable air mass each day.  The sun will be out at times with hazy conditions and random scattered hit and miss showers and storms each day, a few heavy or strong. An early morning or late night thundershower can’t be ruled out, but the main “window of opportunity or risk” will be 1pm to 10pm. (subject to adjustment each day-- hear that on WSB radio) but not raining the whole time so plenty of dry hours each day, no wash-out days foreseen as of now.  Remember the dead horse I’ve been beating for decades: thunderstorm forecasts UNLIKE others sometimes need to be updated every two hours or so (The complex reasons I’ve explained many times before- you miss a blog you miss a lot). At least daytime highs should start to come down by next week with added clouds we break the back of the heat wave. We could even see high temperatures drop to the low to middle 80s and MAYBE drop morning lows to 70 or a bit below.  Early next week the Rossby long-wave jet stream pattern will be shifting the big heat dome ridge to the West allowing a long-wave trough into the Eastern U.S. helping to lower our temperatures but keeping the rain chance at least normal if not above-normal through early next week.  The GFSV3 Global Model indicates a cold front will bring drier air and low 80s starting next Wednesday. However, that would be a rare occurrence, fronts don’t often get that far South this time of year,  so I’ll believe it when I see it and hold off putting it in my forecast for now.  SEE HOW WHAT I DESCRIBED ABOVE PLAYS OUT IN JET STREAM WEATHER MAPS (shaded areas disturbance energy swirls): GFS ENSEMBLE 500MB JET STREAM LEVEL HIGHLIGHTING AREAS ABOVE OR BELOW NORMAL: SURFACE WEATHER MAP DAYS 3-7: SURFACE COLD FRONT PROJECTED NEXT WEDNESDAY: This time of year the normal or average (climate mean) chance of a thunderstorm is 40%.  In the weather pattern above the chance will be at least normal but occasionally 50-70% and on a lucky day 30%, but that can only be determined on a day to day basis and sometimes only 2-4 hours in advance.  ESTIMATED AVERAGE RAINFALL ACCUMULATION BETWEEN NOW AND 8AM MONDAY: For more follow me on Twitter @MellishMeterWSB.
  • Some interesting notes on Barry from hurricane expert Philip Klotzbach of CSU.  *Barry is the FIRST hurricane of the 2019 season, almost 30 days earlier than the average first date of August 10th.  *It made landfall as a Category 1 near IntraCoastal City, LA. *The first hurricane to land in Louisiana since Nate in 2017 and the first in the month of July since Cindy in 2005. *It’s the 4th on record back to 1851 to make a LA landfall in July the others being Bob 79, Danny 97, and Cindy 05. Fortunately rainfall amounts were much less than NOAA/NWS/WPC/NHC anticipated but flooding was widespread none-the-less with many evacuations and numerous roads closed in Louisiana and Mississippi along with a scattering of tornadoes.  It was quite unlike any prior Gulf storm, as radar indicted 20 inch plus rains held offshore even as the center of Barry was 50 miles inland! Mid and upper level dry air and wind shear caused the asymmetrical shape of the rain field cutting down the anticipated rain amounts.  Despite the rain forecast being off on Barry it’s worth remembering how spot-on rain forecasts were well in advance of Harvey in 2017 (Houston record flooding) and for Florence record flooding in NC/SC just last year 2018. That’s two out of three nailed.  And the track and intensity forecasts for Barry were excellent.  In fairness, the National Weather Service DID update rain forecasts to much lower numbers as early as Saturday as the storm made landfall including just a couple inches for New Orleans. Also of note is that Barry originated over land in the U.S. (rare thing) in Kansas and YET was accurately forecast to move into the Gulf and become a tropical system 8 days in advance! Barry almost back to point of origin (10/11 day trip), from Dr. Philippe Papin: Rainfall rates up to 3 inches per hour were observed. Rain totals have still amounted to trillions of gallons over a three state area.  Many homes were damaged by falling trees.  The pumps worked and the levees held in New Orleans which was spared the heaviest rain: Flooding was still bad and widespread across multiple states: It’s not over til it’s over, Depression Barry today: Follow me on Twitter @MellishMeterWSB.
  • I will show you in the maps below how the national weather pattern and our weather changes as the soupy steamy tropical air mass of Barry leaves the scene allowing a high pressure ridge aloft to build a dome of hotter than normal air over much of the country.  ATLANTA  will come under the influence of high pressure surface and aloft with an air flow from the Southwest bringing in more moist air for high humidity while the high pressure provides the heat.  The MAP ABOVE is the projected heat index or “feels like” factor next Saturday July 20th. The chance of a thunderstorm will not be zero with the heat and humidity providing a potentially unstable air mass, but the chance will be 10-20% below-normal for this time of year. Ironically some of the highest temperatures may end up being from I-40 Northward including places like Chicago. The heat comes on as the global wind energy budget changes from -AAM to +AAM as the Pacific El Nino signal weakens. See how the upper level jet stream pattern evolves in the days ahead (ECMWF model 500mb level ~18,000ft): SURFACE WEATHER CHART DAYS 3-7: 3 GLOBAL MODELS ENSEMBLE TEMPERATURE GUIDANCE OUTPUT: They disagree on specific numbers but there’s consensus the heat wave reaches a crescendo next weekend: STATISTICAL BLEND OF MODELS: I think the GEFS and CMC are too extreme as of now so my forecast will reject those numbers for now, but I’ll revisit it when I am back to work Monday.  For more follow me on Twitter @MellishMeterWSB.
  • The current location size and shape of Barry and Tropical Storm conditions, watches and warnings shown in MAP ABOVE.  Barry is a strong tropical storm and continues to strengthen and is expected to reach minimal hurricane status by landfall, BUT it’s the rain not wind that is the main impact. 3 inches an hour or more at times over the weekend 20-30 inch total in some spot not out of the question. OFFICIAL NHC TRACK FORECAST: Isolated tornadoes will also be possible in Louisiana, Mississippi and Western Alabama over the weekend.  For more follow me on Twitter @MellishMeterWSB.
  • Tropical Storm Barry will not have any direct impacts on Atlanta but it WILL influence our rain prospects through at least Monday. The tropical air mass in place will interact with a front moving down from the North which will stall across our region into Monday before dissipating.  This combination will increase clouds and scattered showers and thunderstorms the next 3-5 days some heavy or strong, but with plenty of dry hours and dry areas in-between. REMEMBER, New Orleans can flood 3 ways... water coming down the Mississippi from up North, local downpours, or storm surge from the Gulf. This is a case of ALL THREE.  BARRY FORECAST TO BE AT LEAST A MINIMAL HURRICANE MAX WINDS 75 MPH BY LANDFALL SOMETIME SATURDAY: THE NHC SAYS: MODEL TRACK SPAGHETTI PLOT backs that up with plenty of spread:  The bathtub water temperatures in the Gulf (warmer than normal) are fuel for the storm: For more follow me on Twitter @MellishMeterWSB.
  • A mainly dry day again today with no major change in air mass. The MAP ABOVE shows just spotty thunderstorm coverage for today.  Variable sun and clouds the next 5 days with humidity trending up, temps trending down and coverage of showers and heavy storms on the increase tomorrow into the weekend.  PLEASE READ PRIOR POSTS FOR INFO NOT CONTAINED HERE.  We will be in the squeeze play between a front coming down from the North out of the Midwest and Tropical Moisture coming up from the South. See the sequence here: ACCUMULATED RAINFALL ESTIMATE ENDING 8AM MONDAY: As for potential future Barry the BIG CONCERN is flooding for the Gulf States. The Mississippi is already having flooding from all the Midwest rain water heading South even BEFORE they get any rain from the Tropical system! There’s concern about the levies in New Orleans: ESTIMATED DAILY RAINFALL TODAY THROUGH SUNDAY: Potential for “Barry”. Odds of a Tropical Depression now 90% within 48 hours, possible hurricane by Saturday evening: The Atlanta National Weather Service has a great explanation of the weather set-up next 7 days and some of the uncertainty and risks for Georgia: For more follow me on Twitter @MellishMeterWSB.
  • The chart above shows plenty of warm surface water to support tropical development in the Gulf, only a small pool of slightly below normal temperatures. Surface water temps are now 84-89F, most of my college textbooks put the formation requirement at 82/83F with 80 the bare minimum.  Other tropical systems like this one have developed as a result of upper level (jet stream or slightly lower) energy (vorticity) dropping from land over the Continental U.S. into the Gulf of Mexico such as Alicia in 1983, Bertha 2002 and Edouard 2008. Bonnie in 1986 and the surprise no-name of 1943 may also qualify.  One benefit of this is that without it we’d be developing a scorcher of a heat wave again, instead it will be worse in the Western and Northern U.S. this week and next week: Of course the price to pay will be muggy tropical air and some tropical downpours and more clouds. Here’s an overview of where this has come from and the overall synoptic setting starting July 5th courtesy WeatherSouth: THUNDERSTORM CLUSTERS AND VORTICITY ALOFT: FORECAST 500MB JET STREAM PATTERN SETTING: PROJECTED 850mb HEIGHTS AND VORTICITY 8PM WEDNESDAY: Whether or not it gets a name and regardless of ultimate intensity ALL areas along and near the Gulf Coast should prepare of days of periodic heavy rain, thunderstorms and flooding.  By Friday a FRONT  sinks down from the North and will help “tap into” all the tropical moisture as it stalls across the Southern states through the weekend and into next week: Thus the tropical system will give an assist or boost to our humidity values enhancing cloud cover and providing isolated heavy downpours at times as we roll through the next 7 days (Above). By the way, tropical cyclone/tropical low/tropical depression are all the same thing. All tropical storms and hurricanes are tropical cyclones but NOT all tropical cyclones are depressions tropical storms or hurricanes. (because tropical cyclone is a generic term). Keep in mind that while track forecasts are quite accurate, forecast accuracy for intensity of tropical systems is poor.  With regard to intensity of this system something to note is where it finally develops a closed system. The sooner that happens and the farther South it happens increases the chance it has sufficient time over the bathtub temperatures of the Gulf waters to intensify more, so the farther South and a longer track West would increase odds it reaches hurricane strength (European model and some others).  On the other hand, a formation farther North means less space and time over water for much intensification and a weaker system (American GFS model). Expect model and track forecasts to continue to wobble in all directions as subtle differences in the systems energy and the jet stream (location strength and timing of high and low pressure ridges and troughs) across the Northern U.S. will exert influence on the Gulf system within the margin of error.  I don’t pay too much heed to our “spaghetti plots” until we have an actual entity over water, but FYI: Many models suggest at least the POTENTIAL for rapid intensification to at least NEAR hurricane force but uncertain as to when, how much and where.  For more follow me on Twitter @MellishMeterWSB.
  • This type of close-in development is somewhat rare but certainly not unprecedented.  Forecasters always keep and eye on any front or upper level disturbance that makes its way into the Gulf of Mexico OR the Atlantic during the hurricane season as they can be the genesis for a tropical system when they stall over the warm water.  It could increase  Atlanta’s rain odds next weekend into the follow week but we’ll know more in a few days.  The future PATH AND INTENSITY of this system is very uncertain. Below you can see the best estimate over the next 7 days as of now but expected changes in the days ahead: 5-DAY AVERAGE RAINFALL ESTIMATE: The  DETERMINISTIC OPERATIONAL VERSION OF THE ECMWF has a different idea: However, a bit different tune from the ECMWF ENSEMBLE TROPICAL STORM PROBABILITY: Stay tuned.  For more follow me on Twitter @MellishMeterWSB.