National Weather Summary

National Weather Summary for Wednesday, August 15, 2018

Written by David Moran | Aug 15, 2018 4:25:51 PM

A developing area of low pressure will bring a risk for thunderstorms to portions of the Central and Northern Plains on Wednesday. Some of this activity will have the potential to produce heavy to excessive rainfall. Thunderstorms are forecast from the Southern Plains into the Mid Mississippi Valley and Ohio Valley as an area of low pressure slowly moves eastward. This activity could produce flooding. A cold front will be the focus for the development of thunderstorms across the Northeast. Upslope flow will lead to a risk for thunderstorms capable of producing heavy rainfall across the Southern High Plains. 

  • Thunderstorms for the Central and Northern Plains on Wednesday
  • Excessive Rainfall Wednesday for the Central and Northern Plains
  • Risk for Thunderstorms for the Southern Plains, Mid Mississippi Valley, and Ohio Valley on Wednesday
  • Potential for Excessive Rainfall Wednesday for the Southern Plains, Mid Mississippi Valley, and Ohio Valley
  • Thunderstorms for the Northeast on Wednesday
  • Excessive Rainfall Wednesday for the Southern High Plains
  • Risk for Thunderstorms from the Central Plains to the Mid Mississippi Valley on Thursday
  • Thunderstorm Potential Thursday for the Lower Mississippi, Tennessee, and Ohio Valleys
  • Excessive Rainfall for the Great Lakes Thursday
  • Thunderstorms from the Central Plains through the Tennessee Valley on Friday
  • Potential for Excessive Rainfall Friday across the Ohio and Tennessee Valleys
  • Risk for Thunderstorms for the Northeast and Mid Atlantic Friday
  • Excessive Rainfall Friday for the Northeast
  • Tropical Update


US Hazards

Thunderstorms for the Central and Northern Plains on Wednesday
A developing area of low pressure will bring a potential for additional strong to severe thunderstorms to portions of the Central and Northern Plains on Wednesday. Thunderstorms are ongoing across South Dakota and Nebraska and additional activity is expected during the afternoon. Large hail, damaging winds, and tornadoes will be potential hazards with these storms. Further south, a cold front will be the focus for the development of thunderstorms. Strong winds and large hail will be the primary hazards. Storms will weaken through the evening. 

Major Cities in Region: Goodland, KS, North Platte, NE, Pierre, SD, Grand Island, NE, Sioux Falls, SD


Thunderstorm Risk for Wednesday

Excessive Rainfall Wednesday for the Central and Northern Plains
In addition to the thunderstorm risk described above, there will be a potential for heavy to excessive rainfall. Rainfall amounts of 0.50-1.00 inch with locally higher amounts in excess of 1.50 inches are forecast. 

Major Cities in Region: North Platte, NE, Grand Island, NE


Rainfall Accumulation for Wednesday

Risk for Thunderstorms for the Southern Plains, Mid Mississippi Valley, and Ohio Valley on Wednesday
A slow moving area of low pressure will bring a risk for strong to severe thunderstorms across portions of the eastern Southern Plains, Mid Mississippi Valley, and the Ohio Valley. As thunderstorms develop during the afternoon and early evening, strong winds will be the primary hazard. Storms will weaken during the evening and overnight hours, but rainfall will continue. 

Major Cities in Region: Little Rock, AR, St. Louis, MO, Evansville, IN


Thunderstorm Risk for Wednesday

Potential for Excessive Rainfall Wednesday for the Southern Plains, Mid Mississippi Valley, and Ohio Valley
The thunderstorm activity described above will have the potential to produce heavy to excessive rainfall. Rainfall accumulations of 1-2 inches with locally higher amounts in excess of 3 inches are expected. This may lead to a risk for flooding. 

Major Cities in Region: Springfield, IL, Evansville, IN, Indianapolis, IN


Rainfall Accumulation for Wednesday

Thunderstorms for the Northeast on Wednesday
A cold front moving southeastward across the Northeast will bring a potential for a few strong to severe thunderstorms across region. Thunderstorms will develop along and ahead of the front by late afternoon. Strong to damaging winds and small hail will be the primary hazards with these storms. 

Major Cities in Region: Burlington, VT, Bangor, ME


Thunderstorm Risk for Wednesday

Excessive Rainfall Wednesday for the Southern High Plains
Upslope flow will lead to the development of widely scattered showers and thunderstorms by the afternoon, leading through a threat for heavy rainfall. Rainfall amounts will range 0.25-0.50 inch with locally higher amounts. This may lead to a risk for flooding where the heaviest rain falls. 

Major Cities in Region: Santa Fe, NM, Tucumcari, NM


Rainfall Accumulation for Wednesday

Risk for Thunderstorms from the Central Plains to the Mid Mississippi Valley on Thursday
Ongoing thunderstorms are expected across portions of Nebraska Thursday morning, leaving behind outflow boundaries. Moisture and daytime heating will allow for the redevelopment of thunderstorms by the afternoon. Strong winds and large hail will be the primary hazards with these storms. By the evening, storms will evolve into a complex with damaging winds becoming the primary hazard.

Major Cities in Region: Wichita, KS, Topeka, KS, Omaha, NE, Kansas City, MO, Springfield, MO, Little Rock, AR, Memphis, TN


SPC Convective Outlook for Thursday

Thunderstorm Potential Thursday for the Lower Mississippi, Tennessee, and Ohio Valleys
A slow moving area of low pressure will bring widespread showers and storms, as well as cloudiness to portions of the Lower Mississippi, Tennessee, and Ohio Valleys, to start the day. However, partial clearing and daytime heating may occur ahead of a cold front, allowing storms to redevelop or additional storms to develop in the form of line segments or clusters during the afternoon. Strong winds and hail will be the primary hazards with the stronger storms. 

Major Cities in Region:  Memphis, TN, Evansville, IN, Louisville, KY, Cincinnati, OH, Knoxville, TN, Columbus, OH, Charleston, WV


SPC Convective Outlook for Thursday

Excessive Rainfall for the Great Lakes Thursday
There will be a potential for heavy to excessive rainfall across portions of the Great Lakes on Thursday as the area of low pressure described above moves northeastward. Showers and thunderstorms will move across the region with rainfall accumulations of 0.50-1.00 inch and locally higher amounts expected. This will lead to a risk for flooding.

Major Cities in Region: Grand Rapids, MI, Lansing, MI, Bay City, MI, Detroit, MI, Toledo, OH


Rainfall Accumulation for Thursday

Thunderstorms from the Central Plains through the Tennessee Valley on Friday
Showers and thunderstorms may be ongoing early Friday morning along a cold front. By the afternoon, daytime heating and plentiful moisture will allow for the development of additional thunderstorms. This activity will likely cluster, with damaging winds the primary hazard with the stronger storms. 

Major Cities in Region: Oklahoma City, OK, Fort Smith, AR, Memphis, TN, Nashville, TN, Huntsville, AL, Chattanooga, TN, Knoxville, TN, Asheville, NC


SPC Convective Outlook for Friday

Potential for Excessive Rainfall Friday across the Ohio and Tennessee Valleys
In addition to the thunderstorms described above, there will be a potential for excessive rainfall across the Ohio and Tennessee Valleys. Rainfall totals will range 0.50-1.00 inch with locally higher amounts.

Major Cities in Region: Evansville, IN, Nashville, TN, Louisville, KY,  Lexington, KY


Rainfall Accumulation for Friday

Risk for Thunderstorms for the Northeast and Mid Atlantic Friday
A slow moving area of low pressure will continue to lift northeastward, bringing the threat of strong to severe thunderstorms to the Northeast and Mid Atlantic on Friday. Daytime heating and plentiful moisture will create an environment favorable for the development of thunderstorms. Strong winds and hail will be the primary hazards with the strongest storms. 

Major Cities in Region: Washington, DC, Baltimore, MD, Philadelphia, PA, New York, NY, Albany, NY, Boston,. MA, Portland, ME


SPC Convective Outlook for Friday

Excessive Rainfall Friday for the Northeast
The thunderstorms described above will have the potential to produce heavy to excessive rainfall. Rainfall accumulations of 1-2 inches with locally higher amounts are forecast. This will lead to a potential for flash flooding. 

Major Cities in Region: Syracuse, NY, Burlington, VT, Augusta, ME


Rainfall Accumulation for Friday

Tropical Update
Subtropical Storm Ernesto is located 695 miles southeast of Cape Race, Newfoundland and is moving northward at 8 mph. This general motion is expected to continue with a slight increase in forward speed. By Thursday, the system will turn toward the northeast. Sustained winds are near 40 mph with higher gusts. Some additional strengthening is expected during the next day or so before becoming a post-tropical cyclone Thursday night or early Friday.


Enhanced Infrared Satellite

A Look Ahead
Heavy rain will continue across the Ohio and Tennessee Valleys on Saturday ahead of a cold front. An area of low pressure will develop across the Plains on Sunday, bringing a risk for heavy to excessive rainfall to the Central Plains. This activity will move into the Upper Midwest and Great Lakes on Monday. By Tuesday, heavy rain will extend from the Great Lakes into the Tennessee Valley.