Category: Posts EN

 

We’re approaching the end of an active Atlantic hurricane season. Fall colors are descending further and further south. Frost and freeze warnings are in effect for much of the Mid-Atlantic and southern New England. We’re even seeing a bit of snow over the mountains. But what kind of weather can we expect as we move into the 2018-19 winter season?

 

 

Wintertime weather patterns across the U.S. are typically influenced by the El Nino – Southern Oscillation (ENSO). ENSO is a variation in sea surface temperatures in the eastern Pacific. This cycle of warming and cooling ocean waters in turn affects temperature and precipitation over much of the globe. Model guidance and other signals for the next several months continue to suggest we’re heading towards a weak El Nino, the warm (positive) phase of the ENSO (see graphic above).

 

 

Over the U.S.A. the El Nino is typically associated with an active southern jet stream. More and stronger disturbances pass across the southern tier. This storminess combined with above-normal water temperatures in the Gulf should result in above-normal precipitation across the southern states (see map above). This active southern tier and a typically fast, zonal upper level flow pattern may also limit the intrusion of frigid Arctic air into the States. Warmer-than-average temperatures would be likely over many areas (see map below).

 

 

Of course, long-term trends in precipitation and temperature don’t necessarily have much bearing on snowfall forecasts. For instance, an active southern jet stream can lead to more snow than usual over portions of the Appalachians and Northeast, despite the expectation of normal to warm temperatures.

 

 

A strong cold front has surged south through the Southern Plains. Temperatures this evening are 30-40 degrees colder than this time 24 hours ago across much of central and southern Texas (see map below). This front will become nearly stationary over the region with waves of low pressure traveling along. The result will be periods of heavy rain through much of the work week leading to localized flooding.

 

 

 

Heavy rain has already been falling since yesterday (see map above). Some areas south of Dallas saw up to 3-5 inches, leading to significant flooding, enough to close several highways earlier today. Flooding rains have moved a bit further south for now. However, the front and the focus for heavy rainfall will shift back to the north later in the week. While the cooler air will make storms less likely, the saturated soils will make flooding likely for any moderate to heavy rain that develops. Models suggest some areas could see 5-6 inches of additional rain through the week (map below). Runoff from these heavy rains could also eventually lead to rising streams and rivers late this week into the weekend.

 

 

 

 

Former Hurricane Michael, now a strong post-tropical low, is sprinting into the North Atlantic tonight. Michael slammed into the Florida panhandle on Wednesday and rolled up the Eastern Seaboard through early Friday. Officials are now starting the arduous task of tallying the tremendous damage done by one of the strongest hurricanes ever to hit the United States.

 

 

#Michael has taken and changed lives, left communities in ruins, and even altered the coastline itself. Some of the landmass of St. Joseph Peninsula State Park, just offshore Port St. Joe, no longer exists. It takes powerful storm surge and waves to do this. pic.twitter.com/Q3f2BCmNSZ

— Dr. Rick Knabb (@DrRickKnabb) October 12, 2018

 

NEW: Devastating imagery from the Florida Coast, before & after Hurricane Michael.

Mexico Beach, FL: near total destruction. pic.twitter.com/Hb9Rl9UMKo

— Dakota Smith (@weatherdak) October 12, 2018

 

Aerial view of catastrophic damage to Mexico Beach, Florida. The town took a direct hit by Hurricane #Michael on Wednesday. A devastating category 4 hurricane with winds of 155 mph. Nearly a category 5. pic.twitter.com/VaVBLmum0W

— Zach Covey (@ZachWPDE) October 11, 2018

 

Michael provides a stark contrast to history-making Hurricane Florence which devastated portions of the Carolinas almost a month ago. Florence was a powerful category four hurricane over the open Atlantic, but it weakened before making landfall. The damage caused by high winds was relatively minor. Most of Florence’s deadly impact came from torrential rain as the cyclone slowed to a crawl. Many rivers in the region crested at new record high levels, flooding thousands of homes and businesses.

 

 

Michael moved much more quickly and rainfall totals were much lower (see map above), though still sufficient to produce significant flooding. However, Michael was in the process of rapidly intensifying as it made landfall. Indeed, Michael likely would have reached category five status if it hadn’t made landfall when it did. Michael was the third-strongest hurricane on record to strike the U.S. in terms of minimum central pressure, and fourth-strongest in terms of wind speeds. Michael’s reach extended through the southeast and Mid-Atlantic, not only in terms of general strong winds but isolated tornadoes as well. The current tornado report count stands at 15, but more will likely be added as scientists survey the damage.

 

 

Wind damage where Michael’s eyewall moved through was extreme. The town of Mexico Beach was almost totally flattened. Millions of trees were snapped or uprooted from the Florida panhandle well into southwest Georgia. In fact, Michael was the first category three hurricane to move into Georgia in more than a century, despite having to go through northwest Florida to get there! Michael’s high winds persisted through the southeastern states. It’s estimated that up to a million households remain without power as of Friday evening, mostly in North Carolina. It will take weeks for some rural customers to have their power restored. Lead photo courtesy Staff Sgt. Carmen Fleischmann, Florida National Guard.