There doesn’t appear to be a whole lot of weather going on across the contiguous 48 states this Sunday morning (Jan. 26, 2014), except along the northern tier. However, the national watch-warning map (Fig. 1) can be a bit deceiving, especially when one goes beyond the initial 36 to 48 hour period (the focus of this map). There are also some stories outside the boundaries of the U.S worth noting.
So, here are the top U.S. weather events for today, along with some mentions of longer-term and evolving weather stories. Again, Figure 1 shows the geographical distribution of much of what follows:
(1) The California (and western U.S.) drought continues unabated. Computer models do not promise any significant rainfall until the end of the month and then, rainfall/snowfall will be confined to central and northern parts of California.
Downtown Los Angeles has gone rainless so far this month and no rain is expected there for the next week (and longer). This would only mark the fifth such rainless January in 106 years of records. The other years were 1948, 1972, 1976 and 2003. Note that Los Angeles has recorded no rainfall months in every month of the year.
(2) As a result, the region is a tinderbox. Due to low dew points and low humidity readings, wildfire danger remains high. However, because winds remain relatively light, red flag warnings have not been posted. Still, in the Tehatchapi Mountain region of southern California this morning, dew points were near 10 degrees and humidities were near 40 percent. With daytime heating, relative humidity values in the region will drop dramatically.
Winds are expected to increase in the area later in the week.
(3) It remains warm across southern California and south Florida. Downtown Los Angeles has averaged about 4.5 degrees warmer than usual so far this month. That scenario should continue. In Naples (southwest Florida), it has been a little cooler than average. That’s about to change this week as temperatures rise to between 4 and 7 degrees above average for most of the next 7 days.
(4) The onslaught of cold air continues for the northern Plains. Another clipper system is plowing southward this Sunday morning (Fig. 2). The clipper’s associated cold front will affect the northern Plains today with strong winds, local ground blizzard conditions and rapidly dropping temperatures. For example, Sioux Falls, SD started the day off with temperatures near 40. Winds behind the initial wind shift line have already picked up to 30 miles per hour with gusts to more than 40 miles per hour. When the cold front passes about midday, winds will increase further and the mercury will plummet (to around 10 degrees by sunset).
(5) The cold front will drive southeastward arriving along the Texas-Louisiana Coast by early Monday morning (Fig. 3). The front will continue southeast before slowing down across north-central Florida Monday night. The arctic high-pressure system following in its wake will bring very cold air southward, air cold enough to rival that of early January 2014.
(6) Freeze and hard freeze warnings will dot many parts of the Gulf Coast this week. There’s even a risk of some mixed frozen precipitation developing across parts of the Gulf Coast states.
(7) The parade of clippers and cold fronts has lead to the issuance of gale and heavy freezing spray warnings for almost all of the Great Lakes. Winds are expected to increase to near 40 miles per hour with higher gusts. Waves will build to near 10 feet across parts of Lake Michigan and to as much as 14 feet across parts of Lake Ontario.
(8) On land, downwind from Lakes Michigan, Erie and Ontario, an enhanced “lake effect” will add to the overall snowy pattern in the region. Some places in southwestern Michigan and northwestern New York could net nearly a foot of snow over the next few days. Parts of New York have had two recent heavy lake effect snow events, each dropping as much as much as two feet of snow locally (Fig. 4). Parts of western Michigan have been big snow winners, too.
(9) A major storm system in the north-central Pacific (Fig. 5) is generating a large and long period westerly swell. This will create strong wave action along southern California beaches. While the, “surf is up!” so, too, is the risk of rip currents and “sneaker” waves.
To understand “sneaker waves” (another name for “rogue waves,” I believe), one has to understand that ocean waves are a mix of waves of differing sizes and differing speeds of motion. These waves interact, sometimes reinforcing each other and sometimes interfering or canceling each other. When waves combine, they can generate a disproportionately large, fast-moving, wave. Such waves are often not anticipated and can catch people on beaches and rock outcrops off guard. In early 2013, several people in northern California were killed when attacked by these waves.
(10) Outside of the U.S., the push of arctic cold fronts into the western Gulf of Mexico has lead to arctic air piling up on the north side of the Mountains in southeastern Mexico. As the cold air deepens, it eventually starts to flow through high altitude mountain passes enroute to the Gulf of Tehuantepec. The cold air then accelerates on its downhill ride, leading to high winds and high seas in the Gulf of Tehuantepec. One such event, known as a Tehuantepecer (Fig. 6), was expected yesterday morning with strong northeast winds and high seas. Another can be expected later this week thanks to the next arctic surge.
Overall, the long wave ridge in the western U.S. and the “polar vortex” and long wave trough in the east will allow the current weather pattern to continue for at least the next one to two weeks.
© 2014 H. Michael Mogil