National Weather Summary for Thursday, August 17, 2017
by David Moran, on Aug 17, 2017 10:59:02 AM
As an area of low pressure moves across the Great Lakes Thursday, thunderstorms may develop across the Great Lakes and Ohio Valley ahead of the associated cold front. A front across the Southern Plains will be the focus for thunderstorm development on Thursday.
- Thunderstorms Thursday across the Great Lakes and Ohio Valley
- Risk for Thunderstorms across the Plains on Thursday
- Potential for Thunderstorms Friday across the Central Plains
- Thunderstorms from the Mid Atlantic to the Northeast on Friday
- Excessive Rainfall Friday for the South Central US
- Risk for Thunderstorms across the Central Plains on Saturday
- Potential for Excessive Rainfall Saturday for New Mexico and Texas
- Tropical Update
Thunderstorms Thursday across the Great Lakes and Ohio Valley
As a warm front tracks northward across the Great Lakes, early morning rain and thunderstorms will track east to northeastward across the area. By the afternoon, an area of low pressure and associated cold front will begin to track across the Great Lakes. With southerly flow pumping moisture into the region, some additional instability is expected to build. This instability combined with an increase in wind shear is forecast to result in an increase in shower and thunderstorm activity along and ahead of the cold front. Some of this activity may be strong to severe. Damaging winds and tornadoes will be the primary hazards, especially across eastern Michigan. Some storms may also produce some small hail.
Major Cities in Region: Evansville, IN, Indianapolis, IN, Louisville, KY, Cincinnati, OH, Toledo, OH, Detroit, MI, Cleveland, OH, Pittsburgh, PA
Risk for Thunderstorms across the Plains on Thursday
Moisture will surge northward quickly this afternoon and evening. With daytime heating increasing instability across the region, scattered showers and thunderstorms are expected to develop. Some storms will be strong to severe. Thunderstorms are expected to develop across the Front Range and track eastward into the High Plains late this afternoon and evening. Large hail and damaging winds will be the primary hazards, but an isolated tornado or two cannot be ruled out. By the late evening, storms will weaken and congeal into lines, allowing for a risk for damaging winds across portions of the Central Plains overnight.
Major Cities in Region: Amarillo, TX, North Platte, NE, Pierre, SD
Potential for Thunderstorms Friday across the Central Plains
A weak area of low pressure and strong moisture return across the region will allow for the development of thunderstorms. Storms should develop along the front and move southeastward. Large hail and damaging winds will be the primary hazards.
Major Cities in Region: Topeka, KS, Omaha, NE, Kansas City, MO, Des Moines, IA
SPC Convective Outlook for Friday
Thunderstorms from the Mid Atlantic to the Northeast on Friday
An area of low pressure moving into Canada and the attendant fronts moving into the Northeast will allow for the development of thunderstorms on Friday. Storms may be ongoing during the morning, but additional development is expected during the afternoon hours. Hail and damaging winds will be the primary hazards. In addition, there will be the risk for heavy rainfall amounts of 1-1.5 inches.
Major Cities in Region: Rochester, NY, Washington, DC, Albany, NY, Philadelphia, PA
SPC Convective Outlook for Friday
Excessive Rainfall Friday for the South Central US
As a warm front lifts northward on Friday, areas of excessive rainfall are forecast for the South Central US. Since the region is expected to have already seen plentiful rainfall, any additional amounts may result in flooding. Average amounts of 1-2 inches are forecast.
Major Cities in Region: Tulsa, OK, Fort Smith, AR, Joplin, MO, Fayetteville, AR, Springfield, MO
Excessive Rainfall Risk Outline for Friday
Risk for Thunderstorms across the Central Plains on Saturday
An area of low pressure should intensify across the Central Plains on Saturday, producing strong to severe thunderstorms. Storms should develop across the high terrain and move eastward through the afternoon. Large hail and damaging winds will be the primary hazards with these storms.
Major Cities in Region: North Platte, NE, Dodge City, KS
SPC Convective Outlook for Saturday
Potential for Excessive Rainfall Saturday for New Mexico and Texas
Monsoonal moisture across the Southwestern US should produce showers and thunderstorms across portions of New Mexico and Texas on Saturday, with some heavy rainfall. Rainfall amounts of 1-1.5 inches are forecast.
Major Cities in Region: El Paso, TX, Carlsbad, NM
Excessive Rainfall Risk Outline for Saturday
Hurricane Gert (green oval) is continuing to move east-northeastward at 40 mph and this motion is expected to continue over the next day or so. Maximum sustained winds are near 80 mph with higher gusts. Gert is forecast to become a post-tropical cyclone later today.
An area of low pressure is located about 550 miles east of the Lesser Antilles (red oval) has become better organized overnight. Environmental conditions are conducive for development and a tropical depression could develop later today or tonight as the system moves westward at 15 mph. Regardless of development, locally heavy rainfall and gusty winds are expected to spread across portions of the Lesser Antilles and the eastern Caribbean Sea tonight and Friday.
A second area of low pressure located between the coast of Africa and the Lesser Antilles (blue oval) has become better organized. Gradual development is possible over the next few days while moving west-northwestward at 15-20 mph. Upper level winds are expected to become less conducive for development as it moves north of the Leeward Islands this weekend.
Over the far eastern Atlantic, a tropical wave near the Cabo Verde Islands (yellow oval) is producing disorganized showers and thunderstorms. Further development may occur over the next several days while moving westward to west-northwestward at 15 mph.
Enhanced Infrared Tropical Satellite
A Look Ahead
An area of low pressure should continue to develop across the Northern US on Sunday with a front extending through South Dakota. This may allow for the development of thunderstorms capable of producing hail and damaging winds as they move eastward into the nighttime and overnight hours.
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