Panhandle hook
From Wikipedia, the free encyclopedia
A Panhandle hook (also called panhandle hooker or Texas hooker[1]) is a relatively infrequent storm system whose cyclogenesis occurs in the South to southwestern United States from the late fall through winter and into the early spring months. They trek to the northeast on a path towards the Great Lakes region, as the southwesterly jet streams are most prevalent, usually affecting the Midwestern United States and Eastern Canada. Panhandle hooks account for some of the most memorable and deadly blizzards and snowstorms in North America, as well as tornado outbreaks in the Midwest on record. The name is derived from the region of surface cyclogenesis in the Texas and Oklahoma "panhandle" regions. In some winters, there are no panhandle hook storms; in others, there are several.
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[edit] Formation
A Panhandle Hook storm has its origins as a strong shortwave low pressure system which traverses the base of a long-wave low pressure trough while geographically coincident with the southwestern United States. Such systems ubiquitously develop a surface low-pressure system in the northwestern Texas and western Oklahoma area (as an eddy effect interaction of the topography of the Rocky Mountains in relation to the jet stream) with associated warm front and cold front, with attending snow to the northwest of the low and severe thunderstorms to the southeast -- the "hook" refers to the left-ward east to northeast jog in the track of the surface low as it is plotted on a weather analysis chart.
If the associated jet stream is stronger than normal and there is colder than normal air in place in central Canada to provide a greater than normal temperature contrast with Gulf of Mexico moisture drawn northward by the developing panhandle low, surface cyclogenesis can be particularly energetic and cause a great swath of heavy snow to develop and blanket a large portion of the American Great Plains and upper-midwestern states in conjunction with very strong winds, the combination of which exceeds blizzard criteria. Initially pleasant weather ahead of the northeast-bound storm can lull the unwary into dressing lightly and then being surprised by heavy snow accompanied by howling easterly and northerly winds as the low traverses south to east of their location.
Famous storms that were panhandle hooks are the Armistice Day Blizzard of November 11, 1941 and the storm which sank the Edmund Fitzgerald on November 10, 1975.
[edit] Variations
Many storm systems affect the central and eastern United States each year. Where that storm system emerges from the Rocky Mountains and into the great plains is how the type of that particular storm system is determined. As mentioned, a panhandle hook is area of low pressure takes shape over the panhandle regions of Oklahoma and Texas and is among the most common type of major winter storms in the eastern half of North America, but there are a few variations of a Panhandle Hooks. Two of them in particular have become famous in their own right and have been produced major storms.
[edit] Colorado low
A Colorado Low is similar to a Panhandle hook, but with a slightly different storm track. Instead of emerging into the Great Plains over Oklahoma or Texas, it instead emerges slightly north of that in Colorado. The impact of this different storm track is that it will typically have less access to moisture, and thus will produce lower snowfall amounts in the northern parts of the Upper Midwest.
[edit] Gulf low
The name Gulf Low is an area of low pressure that forms or intensifies over the Gulf of Mexico. Because they move northward from over or near the Gulf of Mexico, these storm systems are capable of transporting copious amounts of moisture with them. At their strongest, these storm systems are even more potent snowfall producers than panhandle hooks. Because of the general west to east movement of weather systems in the mid latitudes of the northern hemisphere, Gulf Lows rarely affect areas west of the Mississippi River. One such exception was the Halloween Blizzard of 1991.
The 1993 North American Storm Complex started out as a Gulf Low before it eventually evolved into a nor'easter. It initially formed in the western Gulf of Mexcio and moved towards Florida before turning to the north and becoming a nor'easter. Another large gulf low storm was the Great Blizzard of 1978, which produced the lowest non-tropical pressure (957 millibars) ever recorded in the United States.
