National Weather Service Storm Prediction Center outlooks for September 18, 2026, placed only a marginal severe thunderstorm risk across the Carolina Piedmont into northern Georgia, northern Iowa, the central High Plains, and Intermountain West, driven by a southward-moving cold front, moderate instability from surface dewpoints in the 60s to near 70°F, and weak upper impulses. Early Day 1 probabilistic tornado graphics showed a narrow 2% contour over parts of Iowa near Des Moines and Ames amid modest shear, but subsequent updates removed all tornado risk areas as convection favored damaging winds and isolated hail instead. No elevated or higher tornado probabilities appeared, consistent with limited low-level shear and the absence of strong supercell-favorable setups that day.
Tóm tắt AI thử nghiệm tham chiếu dữ liệu Polymarket. Đây không phải tư vấn giao dịch và không ảnh hưởng đến cách thị trường này được giải quyết. · Cập nhậtWhich cities face tornado risk on September 18?
Chicago, IL
1%
Houston, TX
<1%
San Antonio, TX
49%
Dallas, TX
<1%
Austin, TX
1%
Fort Worth, TX
49%
Columbus, OH
90%
Charlotte, NC
1%
Indianapolis, IN
<1%
Denver, CO
1%
Nashville, TN
1%
Oklahoma City, OK
1%
Memphis, TN
1%
Louisville, KY
1%
Atlanta, GA
1%
Kansas City, MO
<1%
Omaha, NE
1%
Minneapolis, MN
25%
Wichita, KS
<1%
New Orleans, LA
<1%
Tampa, FL
1%
St. Louis, MO
1%
Birmingham, AL
1%
Des Moines, IA
<1%
Little Rock, AR
24%
$376 KL.
Chicago, IL
1%
Houston, TX
<1%
San Antonio, TX
49%
Dallas, TX
<1%
Austin, TX
1%
Fort Worth, TX
49%
Columbus, OH
90%
Charlotte, NC
1%
Indianapolis, IN
<1%
Denver, CO
1%
Nashville, TN
1%
Oklahoma City, OK
1%
Memphis, TN
1%
Louisville, KY
1%
Atlanta, GA
1%
Kansas City, MO
<1%
Omaha, NE
1%
Minneapolis, MN
25%
Wichita, KS
<1%
New Orleans, LA
<1%
Tampa, FL
1%
St. Louis, MO
1%
Birmingham, AL
1%
Des Moines, IA
<1%
Little Rock, AR
24%
The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If the city's coordinates fall inside any area rated 2% or higher, that city resolves "Yes". If a city is outside all tornado probability areas, or only within areas rated below 2%, that city resolves "No".
The SPC outlook is published as machine-readable geographic data (GeoJSON) at spc.noaa.gov. Each city's coordinates and the polygon boundaries are publicly verifiable. Borderline cases can be independently confirmed using the polygon data (excluding the hatched SIGN overlay, which is not a probability rating) and the city's listed coordinates. The point-in-polygon test is performed on unprojected WGS84 (EPSG:4326) coordinates, which is the native coordinate system of the SPC GeoJSON data.
Resolution is based on the scheduled 01:00 UTC Day 1 Convective Outlook update issued on the following UTC calendar day. The SPC Day 1 outlook covers a 24-hour period from 12:00 UTC to 12:00 UTC the following day. Subsequent revisions published after that scheduled update will not be considered. If the SPC Day 1 Convective Outlook has not been published by the time the market closes, this market will resolve to "No".
The resolution source for this market is the NOAA Storm Prediction Center at spc.noaa.gov.
This market uses coordinates 41.8781, -87.6298 for Chicago, IL.
Thị trường mở: Sep 18, 2026, 8:13 AM ET
Nguồn giải quyết
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlNgười giải quyết
0x65070BE91...The SPC Day 1 Convective Outlook assigns tornado probability percentages (2%, 5%, 10%, etc.) to geographic areas across the US. If the city's coordinates fall inside any area rated 2% or higher, that city resolves "Yes". If a city is outside all tornado probability areas, or only within areas rated below 2%, that city resolves "No".
The SPC outlook is published as machine-readable geographic data (GeoJSON) at spc.noaa.gov. Each city's coordinates and the polygon boundaries are publicly verifiable. Borderline cases can be independently confirmed using the polygon data (excluding the hatched SIGN overlay, which is not a probability rating) and the city's listed coordinates. The point-in-polygon test is performed on unprojected WGS84 (EPSG:4326) coordinates, which is the native coordinate system of the SPC GeoJSON data.
Resolution is based on the scheduled 01:00 UTC Day 1 Convective Outlook update issued on the following UTC calendar day. The SPC Day 1 outlook covers a 24-hour period from 12:00 UTC to 12:00 UTC the following day. Subsequent revisions published after that scheduled update will not be considered. If the SPC Day 1 Convective Outlook has not been published by the time the market closes, this market will resolve to "No".
The resolution source for this market is the NOAA Storm Prediction Center at spc.noaa.gov.
This market uses coordinates 41.8781, -87.6298 for Chicago, IL.
Nguồn giải quyết
https://www.spc.noaa.gov/products/outlook/day1otlk.htmlNgười giải quyết
0x65070BE91...National Weather Service Storm Prediction Center outlooks for September 18, 2026, placed only a marginal severe thunderstorm risk across the Carolina Piedmont into northern Georgia, northern Iowa, the central High Plains, and Intermountain West, driven by a southward-moving cold front, moderate instability from surface dewpoints in the 60s to near 70°F, and weak upper impulses. Early Day 1 probabilistic tornado graphics showed a narrow 2% contour over parts of Iowa near Des Moines and Ames amid modest shear, but subsequent updates removed all tornado risk areas as convection favored damaging winds and isolated hail instead. No elevated or higher tornado probabilities appeared, consistent with limited low-level shear and the absence of strong supercell-favorable setups that day.
Tóm tắt AI thử nghiệm tham chiếu dữ liệu Polymarket. Đây không phải tư vấn giao dịch và không ảnh hưởng đến cách thị trường này được giải quyết. · Cập nhật

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