We didn’t really do a lot of forecasting this month, as most of our attention was tied to the dangerous and persistent tropical season. Dorian and Imelda took a lot of our attention, but when we were, albeit briefly, focused on the Mainland, it was WeatherNation who snuck in for a victory.
Just to provide some context for just how big these United States are, we will be staying entirely west of the Mississippi and remain in states that border either the Gulf of Mexico or the nation of Mexico, and we will still be traveling 1,842 miles and taking 3 long days to get where we are going. We’ll even take interstates, so we’ll cover 68mph, and 546 miles per those first two days, and we’ll STILL have a lengthy 11 hour day to finish with.
DAY ONE (Wednesday) There is a stout ridge of high pressure in the southeastern United States, and most of the precipitation for the next couple of days will be ridge riding on the north side of this dome, meaning very hot, dry and mostly sunny weather in the southeast, including in Louisiana and east Texas. The western edge of this dome will be in west Texas, but we will stop in Childress, before we run into the associated showers and thunderstorms. Hopefully, the AC works in the hotel.
DAY TWO (Thursday) As is the nature of shower activity on the backside of high pressure, it won’t be moving anywhere, but it’s coverage will probably expand through the day on Thursday. Expect some showers and storms through Amarillo, and as we cross into New Mexico, rain will lighten, but persist. In fact we may see rain persist right up to Tijeras, butting up against the foothills of the mountains surrounding Albuquerque. We’ll be in the clear, however, by the time we reach New Mexico’s biggest town, and will drive in sun to Manuelito, just before the Arizona line.
DAY THREE (Friday) High elevation rain showers may encroach the hills east of Manuelito, but that will be the only threat for this long finishing day of our trek. Strong low pressure is going to develop in the Rockies, kicking up a Santa Ana wind that may necessitate a firm grasp of the steering wheel. particularly as the day reaches it’s final stages, and we turn north into the San Joaquin Valley. Fresno will be mild and could be fairly breezy.
There is an enhanced risk for severe weather today in Minnesota, though at present, the radar is pretty sparse, save for a few showers in northern Minnesota and the first severe storm in northwest Iowa.
This radar imagery is from about 4:15. Here is a look at the HRRR forecast radar for about 630 this evening.
It looks as though the guidance is a little behind schedule, but the most important thing to note, will be how fast this line develops. This is the forecast radar 45 minutes later, or 715.
This looks like a strong line from Mankato to Storm Lake. Note the distinct blobs within the line. The threat for tornadoes and large hail is real tonight, and it is evidenced by the depiction of discrete cells within this line.
Eventually, and only within another 45 minutes, the storm will metastasize into a line. It will still be strong, and straight line winds will be added to the mix of threats.
This is the epitome of the “pay attention to the skies” days in southeast Minnesota and northern Iowa. Strong, dangerous storms are likely tonight, and they are likely to develop rapidly. It is possible that strong storms can develop and produce tornadoes even between radar scans with rapid development such as this.
Stay alert, heed local warnings, and listen to your gut. If it seems dangerous, take shelter, even if a warning has not yet been issued.
*Even as I was writing this, a tornado watch was issued for the region*
Meteorologists everywhere feel a twinge of guilt and pain every time severe weather targets life and property. We all love the weather, but when it turns ugly, it hurts a little differently, like we have somehow been betrayed. It’s worse when the bad weather is somewhat unanticipated.
Imelda was never anticipated to be a strong storm, in terms of central pressure, or wind speed, and it wasn’t anticipated, originally, to linger very long. Eventually, the storm did slow down and tracked over the same tract of land for about 48 hours. The result is images that resemble those from Hurricane Harvey, particularly between Houston and Beaumont.
Here is a look at the heaviest rain of the past 24 hours. There is a swath from the Woodlands in the east Houston metro to Beaumont that saw 10+ inches of rain today. Over the course of the storm, that same area saw close to 2 feet.
I’ve underlined Houston and Beaumont on the map which should show you something else from a couple of different perspectives. Either you will see this map, depending on your perspective. Either you will note that the is a lot of rain for a very large area, or you will note that this is actually a lot less rain than the area saw with Harvey. Both conclusions are true, and should be telling.
Even though there is quantitatively less rain from Imelda, there was a lot of rain for a very large area IT was disruptive, deadly, destructive and evocative of the all time crisis that Harvey brought. This should underscore just what a nightmare Harvey was, but also sound an alarm about the eminent threat of any tropical feature. Just because Imelda’s torrential rain affected a smaller footprint doesn’t mean it wasn’t a major catastrophe. Imelda didn’t bring 5 feet o rain, but 2 is still pretty overwhelming.
Usually, when you think of mountains, you think of snow capped peaks and chilly air. In Greensboro last week, they were directly responsible for temperatures not cooling off as quickly as it could have. cold air was rushing south from the Great Lakes, but got hung up in the mountains. Southerly flow with humid air produced clouds and a bit of rain that certainly allowed for a cooldown, but not quite on the order forecast by our model guidance for Friday. Weatherbug had a blend of a good temperature forecast, and were one of only three that had rain in the forecast on Thursday. Actuals: Thursday – .01 inches of rain, High 95, Low 72 Friday – .01 inches of rain, High 82, Low 72
Before we begin, I want to highlight just what a miserable several days it’s been in southeastern South Dakota. Three EF-2 tornadoes embedded in a strong squall line tore through the south side of Sioux Falls, the state’s largest city Tuesday night. The massive devastation goes to prove, once again, that these strong squall events should be taken very seriously, because these tornadoes were so quick and briefly on the ground, they were over almost as soon as they were detected on radar.
The heaviest damage seemed to occur in one of the main commercial areas of the city, passing through a shopping center and a mall parking lot, and most noticeably tearing to shreds an Advanced Auto Parts. The City of Sioux Falls added this drone footage to their Twitter feed.
While the tornadoes were embedded in a squall line, the squall line was a part of a persistent pattern of wet weather, that brought massive flooding to southeastern South Dakota and southwest Minnesota. Large tracts of I-90 were closed west of Sioux Falls to Mitchell, and many towns, including Madison, were cut off from the outside world by the rising rivers and creeks in the area. Many places received a foot of rain in a 72 hour period, and the region will remain wet this week. Let’s hope for better days soon.
As for the forecasting in the month of October, WeatherNation’s strategy of associating closely with the Weather Service and changing course only when necessary really only works if you find those situations where you can add value on your own. Well, in August, they did. Not only did WeatherNation win the forecasting title, the NWS dropped all the way to third. Congrats to WeatherNation. (Charts below are for daily forecasts)
We took a look at the central Valley in California early last week, and it was a pretty tough verification. Not, perhaps, in the way you think. Fresno wasn’t going to see much weather, and it’s position on the west coast led the lot of us forecasters to rely heavily on model guidance. As a result, there was a FIVE way tie at top of the leaderboard, and the other two outlets, The Weather Channel and Weatherbug were only a degree behind. The trend was for a cooler Tuesday than models indicated, so the forecasts were consistent, they were consistently too warm. Actuals: Monday High 102, Low 72 Tuesday – High 99, Low 70
The Carolinas were clipped by Dorian, with coastal sections of the states from Charleston to the Outer Banks sustaining damage, primarly due to storm surge and some isolated tornadoes, like the one in North Myrtle Beach. Greensboro was largely unaffected, and now can look instead to the west for their upcoming weather.
At 1152AM, ET, Greensboro was reporting a temperature of 79 degrees with fair skies. There was a little bit of cloud cover across the region, but not so much that the satellite was very busy. A stalled boundary suspended between two areas of low pressure in the Great Lakes was inducing a generally southerly flow, which will likely lead to low clouds and fog when temperatures start to wane. The western low will start to occlude, while the cold front attached to the boundary to the east will begin to sink further south, decoupling from the western low. There won’t be much energy with the tail of this front as it passes into North Carolina, but after sunset, destabilization aloft might lead to a few showers and storms on Friday evening. Tomorrow – Sunny and humid, High 92, Low 73 Friday – Mostly cloudy with increasing chances of rain. Cooler, High 83, Low 71
TWC: Tomorrow – Except for a few afternoon clouds, mainly sunny. high 95, Low 72 Friday – Scattered thunderstorms High 81, Low 71
AW: Tomorrow – Mostly sunny, hot, High 94, Low 71 Friday – Intervals of clouds and sun, a couple of showers and a thunderstorm, mainly later; warm High 83, low 72
NWS: Tomorrow – A slight chance of showers and thunderstorms after 2pm. Patchy fog before 9am. Otherwise, sunny, High 94, Low 71 Friday – A chance of showers and thunderstorms, mainly after 1pm. Increasing clouds, High 86, Low 70
WB: Tomorrow – Sunny. Patchy fog in the morning. A slight chance of showers and thunderstorms in the afternoon. High 93, Low 73 Friday – Partly sunny. A chance of showers and thunderstorms in the afternoon, High 83, Low 73
WN: Tomorrow – Partly cloudy with isolated storms, High 94, low 72 Friday – Partly cloudy with scattered storms, High 86, Low 70
FIO: Tomorrow – Humid and mostly cloudy throughout the day. High 93, Low 70 Friday – Humid and partly cloudy throughout the day. High 84, low 70
Model guidance suggests that temperatures will actually be in the high 70s on Friday, but note how nobody is on board with that. This is because guidance often fails to cope with terrain’s influence on temperature. That heavy, cold air will struggle to clear Appalachia, and with a blanket of mid level clouds, radiative cooling will be unlikely. Here is the satellite, with no clouds to speak of this morning.
By now, we’ve all heard the stories of utter devastation for the northern Bahamian islands of Great Abaco and Grand Bahama. The initial storm surge put a lot of Abaco underwater at the initial landfall, and many deaths on the island were the result of drowning during the storm surge, while in this case, the eye’s passage overhead provided a chance for many to get to higher, safer ground.
The storm then sat and spun over the eastern side of Grand Bahama, cutting the largest city, Freeport, off from the rest of the island. The destruction there, thanks to persistent triple digit wind speeds and a very high storm surge, is comprehensive.
Dorian’s slow down fortunately spared the Floridian coast from the worst damage, but the storm spiraled northwards and pummeled Georgia and the Carolinas with rain, storm surge, tornadoes and category 2-3 winds, before it made a brief trek over the Outer Banks, with a landfall at Cape Hatteras. Take a look at the radar imagery to see how close the eye was to Charleston and Wilmington at various points.
Dorian moved away from the Carolina coast and as he weakened, broadened his footprint, meaning more rain and cloud cover further from the center of the storm. A course directly up the Gulf Stream and away from land will allow for maintained intensity until he made another landfall, this time over the weekend in the Canadian Maritimes.
Dorian tracked directly over Halifax, Nova Scotia with hurricane strength winds, and thought it didn’t approach the intensity it had when the storm swept through the Bahamas, he did considerable damage there as well.
The above video provides a good recap of the storms entire course. At least 45 people are confirmed to have died in Dorian’s path, with the majority of the fatalities in the Bahamas, though many more are possible when the affected islands are accessible.
If you can help out and choose to do so, the Red Cross is always accepting donations.