Moderate Risk for severe weather across the Plains

Severe weather is expected from the Red River Valley through the Ozarks and into the Tennessee valley.  Large to giant hail, widespread severe wind gusts and Tornadoes are anticipated.

A mid-level trough is moving into the northern Plains and will continue to advance eastward.  The trough should reach the upper Mississippi and Missouri Valleys by tonight.  This trough will bring several smaller disturbances across the Plains and mid to upper Mississippi Valley today.

In the western portions of the risk area, from Central and Eastern Oklahoma as well as northern Texas, there will be strong capping in place.  That cap will prevent storms from forming earlier in the day but as lifting forces increase throughout the afternoon, some storms will form and develop rapidly due to favorable profiles.   The overall risk is lower from the Red River Valley up into Northeastern Oklahoma due to this cap, which will allow the cold front to form a line of storms, but any supercells that form before the passage of the front has the potential to be dangerous.  Strong tornadoes and giant hail are risks in these supercells, though the risk becomes more limited the further south you go into Texas.

Further north and east, The potential exists for a swath of damaging wind gusts to occur from eastern Kansas to the mid Mississippi Valley this afternoon and evening.  There are some questions about the development of storms along an outflow boundary this morning from the current storms taking place.  Additional storms this morning would help limit the risk in this area, but capping over the area is expected to keep the number of early morning storms low and keep the risk higher this evening.  Do not be surprised if the Storm Prediction Center puts out an area of high risk later on this morning if only small amounts of convection form and a better location for the deep convection is ascertained.

This convection will all begin to take a linear form as the cold front continues to push east and a convective complex is possible along the cold and warm front that’s will be in the region.  This will approach the Mississippi Valley this evening and into tonight.

 

Rob

Severe weather shifts east into the River Valleys

An upper low currently crossing eastern Kansas is forecast to accelerate eastward across Missouri and into the Midwest by tonight.  This system, along with a shortwave trough moving into the Gulf of Mexico will quickly shift a cold front across the southeast.  This front is expected to be span from the Ohio Valley down to the Florida panhandle by Friday morning.

Current Conditions

 

Currently, the last of the Tornado Watches has expired.   Strong to severe thunderstorms continue to shift east through Louisiana and Mississippi with a few strong storms up in Illinois.  The storms in Illinois should weaken this morning,  but the southern storms across the gulf states will remain locally severe.

Cloud cover from the current storms will help limit some of the day time heating this afternoon.  The Storm prediction center had a moderate risk area in the forecast yesterday.   This has been downgraded to enhanced this morning.  Do not be surprised if a smaller area of moderate risk re-appears this afternoon as the location of the most destabilization becomes obvious.   The entire area should see at least some instability along and ahead of the cold front, which should be along the Mississippi River by Midday. This front will shift east and provide the mechanism by which storms will form.

Severe Risk

New storm development is expected my early to mid afternoon.  Rotation should be limited with height, but speed shear should generate enough rotation to make tornadoes a risk for a large area as rotating supercells and small bow echoes become possible, particularly over the lower Ohio Valley.

Expect hail and strong winds to remain a risk from this afternoon into the overnight hours near the Appalachians.  The risk will shift even further east into the D.C. area by Friday.  The system should be much weaker with a lower risk for severe weather at that time.  The northeast will even be experiencing snow Friday into the weekend.

Hermine continues to slam the East Coast

Hermine, still a tropical storm, is moving toward the northeast near 22 mph, and this general motion is expected to continue with some decrease in forward speed through Saturday night. A gradual turn toward the north is expected on Sunday.  On the forecast track, the center of Hermine will continue to move across eastern North Carolina during the next several hours and emerge over the Atlantic later today.  Maximum sustained winds remain near 60 mph with higher gusts.  Strengthening is forecast after the center moves over water, and Hermine could be near hurricane intensity by Sunday.  Tropical storm force winds extend outward up to 185 miles mainly to the south and east of the center.   The estimated minimum central pressure is 997 mb.Hermine

 

SUMMARY OF WATCHES AND WARNINGS IN EFFECT FOR TROPICAL STORM HERMINE:

A Tropical Storm Warning is in effect for…

Surf City, North Carolina to Sandy Hook, New Jersey, including Pamlico and Albemarle Sounds, Chesapeake Bay from Drum Point southward, the Tidal Potomac from Cobb Island eastward and  Delaware Bay

A Tropical Storm Watch is in effect for…

North of Sandy Hook, New Jersey to west of Watch Hill, Rhode Island, including Long Island.

 

Tropical storm conditions will continue to spread northward within the warning area along the Atlantic coast through Sunday.  Tropical storm conditions are possible in the watch area by
late Sunday or Sunday night.   The combination of a storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline.  There is a danger of life-threatening inundation during the next 24 hours in the Hampton Roads area as a storm surge of 3-5 feet comes ashore.  Persons within this area should take all necessary
actions to protect life and property from rising water.  There is also the possibility of life-threatening inundation during the next 48 hours at most coastal locations between the North Carolina/Virginia border and Bridgeport, Connecticut as storm tides of 2-4 feet come ashore.  These tides will combine with expected rainfall accumulations of 4-7 inches from Southeastern Virginia and Atlantic Coastal Maryland and may contribute to additional flooding.

Storm surge Hampton Roads storm surge New york Philly New England

Hermine is beginning to undergo an extra tropical transition, but once back over open waters, may redevelop her tropical characteristics and should approach Hurricane Strength off the Delmarva while south of New England.   Areas north of Virginia under a Tropical Storm Warning or Watch should prepare for conditions to worsen throughout the weekend, as should coastal areas of Massachusetts and Rhode Island.

Major severe risk across Ohio Valley

A moderate severe risk will bring widespread Damaging Wind gusts in excess of 70 miles per hour along with tornadoes and isolated large hail are expected this afternoon and evening from Northeast Iowa into extreme Southern Wisconsin, Northern Illinois, Southwest Michigan, North and Central Indiana and Western Ohio.  The wind damage threat will affect the Upper Ohio Valley Late this evening into the Central Appalachian Mountains during the overnight period. 

severe risk

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 50,489 17,159,246 Chicago, IL…Fort Wayne, IN…Aurora, IL…Dayton, OH…Rockford, IL…
ENHANCED 75,211 14,071,627 Indianapolis, IN…Columbus, OH…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…
SLIGHT 114,349 25,466,262 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
MARGINAL 242,590 39,815,217 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

A belt of stronger westerly winds will persist across the northern tier states including the Great Lakes and Ohio Valley.  There is a shortwave trough embedded within the stronger winds aloft.  This trough will move from Northern North Dakota to the Upper Great Lakes by this evening.  This trough, along with a surface low over Nebraska.  A warm front extends from this low through Southern Iowa and Southern Iowa into Southern Indiana.  This warm front will move north into Northern Illinois today as the low moves into Eastern Iowa this afternoon. 

Strong storms from this morning, which had prompted several Severe Thunderstorms this morning, shifted southeastward along the convectively enhanced warm front.  This movement was in response to a strong southwesterly low level jet stream.  As the Warm front moves north, moist low level air will bring dew points into the 70s from the Mid-Mississippi Valley to the Ohio Valley.  Storms will develop in the vicinity of and north of this warm front with supercells being the primary initial mode of storm.  Very Large Hail will be likely with the initial storms. 

Colin4

Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 25,480 10,316,848 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
30 % 12,213 4,222,164 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
15 % 90,996 18,409,308 Chicago, IL…Indianapolis, IN…Minneapolis, MN…St. Paul, MN…Fort Wayne, IN…
5 % 191,529 34,507,995 Detroit, MI…Columbus, OH…Milwaukee, WI…Cleveland, OH…Raleigh, NC…

 

There is a significant risk of Tornadoes with these storms, especially across Northeastern Iowa, Southern Wisconsin and Northern Illinois west of Chicago.  But the risk extends across the Ohio Valley into the Appalachians into the overnight hours. 

tornado outlook

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 24,082 6,403,348 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
10 % 41,673 13,277,336 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
5 % 71,076 14,627,057 Indianapolis, IN…Columbus, OH…Milwaukee, WI…Toledo, OH…Cincinnati, OH…
2 % 105,218 19,386,926 Detroit, MI…Cleveland, OH…Pittsburgh, PA…Lexington-Fayette, KY…Akron, OH…

 

Storms will grow upscale into a fast moving mesoscale convective system and Derecho.  The primary threat across the Ohio Valley into the Southern Great Lakes will be strong and damaging straight line winds.  Conditions appear favorable for a swath of significant damaging winds during the late afternoon and early evening. 

severe watch

Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 82,916 22,731,124 Chicago, IL…Indianapolis, IN…Columbus, OH…Cincinnati, OH…Fort Wayne, IN…
45 % 51,341 17,323,133 Chicago, IL…Columbus, OH…Fort Wayne, IN…Aurora, IL…Dayton, OH…
30 % 75,230 13,798,843 Indianapolis, IN…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…Akron, OH…
15 % 114,507 25,961,856 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
5 % 241,275 39,436,728 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

Robert Millette

Staff Meteorologist

Firsthand Weather