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Major Hurricane Willa Roars Into Southwest Mexico; Could Fuel U.S. East Coast Storm!

Written by Team Morecast

 

Hurricane Willa is slamming the Mexican states of Nayarit and Sinaloa tonight with destructive winds, storm surge, and flooding rainfall. Although the cyclone will break up quickly over the rugged mountains of central Mexico, the remnant energy will emerge over the southeast U.S. later this week. Merging with a trough ejecting from the Plains, Willa’s ghostly remnants could spawn a pre-Halloween Nor’Easter by next weekend!

 

 

 

Willa made landfall as a category three storm near Isla Del Bosque in the state of Sinaloa around 7 p.m. local time Tuesday evening. Willa is the first major (category three or higher) hurricane to hit the Pacific coast of Mexico since 2015, and only the fifth since 1989. It’s part of a very active 2018 Pacific cyclone season. Between the western and eastern tropical basins, more than 48 storms have been named, including 17 major hurricanes (called supertyphoons in the western basin). Fortunately, we’re approaching the end of the season as October turns to November.

 

 

The prospects for an east coast storm in the U.S. are increasing. An upper level trough will sweep the remnants of Willa from the northern Gulf coast towards the southeastern states. This extra energy will spark a rapidly intensifying surface low near the Outer Banks late Friday. This storm will rake the Mid-Atlantic and Northeast coasts through the weekend. Gusty onshore winds will accompany this storm, causing high surf and potentially leading to some beach erosion. Minor wind damage and localized flooding rainfall could occur, too.

Dangerous Hurricane Willa About to Thrash Southwest Mexico!

Written by Team Morecast

 

As expected, small but powerful Hurricane Willa has exploded in strength the last two days. Willa reached category five status earlier today. Although it has weakened just below the category five threshold this afternoon, the hurricane is still poised to lash the Pacific coast of central Mexico. The Mexican states of Sinaloa and especially Nayarit will see devastating winds, flooding rains, and deadly storm surge on Tuesday.

 

 

The table above shows how rapidly Willa intensified from a tropical storm on Saturday to a category five nightmare Monday morning. Willa strengthened so quickly in part because of its small size. The cyclone was able to concentrate energy in a smaller area, enabling faster intensification of the core. This small size will be beneficial in limiting the area of destruction. However, where Willa does strike, the damage will be extreme. Near and just east of where Willa makes landfall, destructive winds to 150 mph (240 kph) and a deadly storm surge exceeding 10 feet (3 m) will occur. Heavy rainfall will be enhanced by the mountainous terrain at the landfall point. Some areas will see 12-18 inches (300-450 mm) of rain in a very short amount of time, triggering deadly flash flooding and landslides.

 

 

Willa will weaken quickly over the mountains of central Mexico. However, the remnants of Willa will emerge over the northern Gulf of Mexico later this week. Those remnants will combine with a trough over the eastern U.S. There are indications that a strong coastal storm could develop from this merger by next weekend. If it does, locations along the eastern seaboard could see high winds and heavy rains. We’ll keep a close eye on this potential as we move through the week.

Warm Winter Ahead For Much of the United States

Written by Team Morecast

 

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.

 

Wet Week Ahead for Texas, Flash Flooding Likely!

Written by Team Morecast

 

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.