Posts

The importance of the EPO and upcoming cold risks

For some time now, we have discussed the likelihood that colder than normal air would be a common theme in the Northern and Eastern United States during the month of December. Like most things, it was not expected to be constant, but it was expected to be prevalent, and especially when compared to the past few December’s which featured nearly coast-to-coast anomalous warmth in the United States.

After a warm start, colder than normal air invaded the Great Lakes, Ohio Valley and Northeast during December’s second week. Winter weather threats have followed, with many areas recording multiple snowfalls. While this airmass hasn’t broken records, it has been just as anomalous as advertised, and has had an obvious impact on markets and businesses. After a brief period of moderation, forecast models are beginning to signal the return of arctic air into the USA – and this time it may be more anomalous than before.

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Winds of change blowing as cooler risks set to return

Happy Monday! Much of the past several weeks have featured a similar synoptic weather headline across North America: Trough west, ridge east. This pattern had led to large scale above-normal temperature anomalies from the Plains eastward to the Mississippi River, exacerbated near the East Coast. But there are growing signs that this pattern will be changing over next few weeks.

Until now, the pattern has been largely driven by the presence of tropical forcing, from the ENSO regions where La Niña conditions have essentially taken over. We can use multiple measures and analytical approaches to understand exactly how the tropical convection is impacting global circulations, one of them being the SOI. This essentially lets us know if the atmosphere is responding in line with an El Niño, La Niña or neither.

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Major Hurricane Irma and Its Potential Future

Good evening! After the devastation and catastrophic flooding from Harvey meandering over South Texas and Southwest Louisiana over the past week, we were finally relieved to see that that storm has now moved out of the Western Gulf of Mexico region. Heavy rainfall will continue over the next few days over the Tennessee Valley from the remnants of Harvey, before it becomes absorbed into a frontal system developing over the Northeast. But as we approach the peak of hurricane season, more tropical threats are rising. One such threat is Hurricane Irma which is becoming a powerful hurricane already today.

Irma has been rapidly intensifying over very warm waters and a favorable atmospheric environment, since it became a tropical storm on Thursday. It is now a major Category 3 hurricane with maximum sustained winds at 115mph. Irma will continue moving on a west-northwest path over the Eastern Atlantic over next few days. It will be moving over slightly cooler waters (still sufficient for maintenance at around 26 C) and some mid-level dry air from ridging, which might at times slow down the rate of intensification over the next 2-3 days.  But overall, an upper-level anti-cyclone will support low shear and more upper-level outflow over the hurricane. So Irma will likely continue to strengthen into a Category 4 by early next week.

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Premium Long Range: Cooler, Active Pattern Next Week…More Changes Late Month?

Good morning! More summer-like weather with more heat and humidity will continue for the rest of the week,with some scattered showers and thunderstorms possible each afternoon or evening. But it appears the Western Hemispheric pattern will undergo another more significant changes to support some cooler weather again for next week.

First changes, will start occurring over North Pacific as usual this week. An upper-level low will be near the Aleutian Islands or Southwest Alaska. This will cause a high-amplitude ridge to build over the West Coast by early next week. This will result in a larger trough digging and encompassing much of the Central and Eastern US over for next week.  Then cooler airmasses from Canada will be invading the CONUS, with temperatures well below over the much of the Northern and Central Plains and into parts of Great Lakes and Ohio Valley.

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