Yes, a Dense Fog Advisory means that there will be fog, and it will be dense. Yes, a Dense Fog Advisory means that there will be fog, and it will be dense. The normal end of the growing season is mid to late October west of the Blue Ridge and early November east of the Blue Ridge. Pronósticos, Education/Outreach Tour Requests When this happens, visibilities frequently drop to one-quarter of a mile or less. CallUrl('www>weca>orghtml',0), ~TildeLink() A ~TildeLink() is issued when fog that reduces visibility to 1/4 mile or less is possible in the advisory area. Small Craft Advisories are issued for the Tidal Potomac River and the Chesapeake Bay when one or both of the following conditions is expected to begin within 36 hours: 1) sustained winds of 18 knots to 33 knots. A Wind Chill Warning is issued when wind chills of -20F or lower are expected east of the Blue Ridge Mountains, and when wind chills of -25F or lower are expected along and west of the Blue Ridge Mountains and in Frederick and Carroll Counties in Maryland. Please select one of the following: National Oceanic and Atmospheric Administration. 3)  a life threatening or damaging combination of snow and/or ice accumulation with wind. CallUrl('www>pepperridgenorthvalley>comphp',0), ~TildeLink()- Issued when fog is expected to reduce visibility to 1/4 mile or less over a widespread are for at least 3 hours.Density Of Air- The mass of air divided by its volume. Such flooding would potentially pose a serious risk to life and property. It does not mean that significant and hazardous winter weather will occur...it only means it is possible. In this way, a fender bender between two cars on the highway can quickly become a deadly multi car pile-up. A High Wind Watch is issued when the following conditions are possible: 1) sustained winds of 40 mph or higher for one hour or more . And so, in my quasi weekly 'What’s that Warning?’ series, I will be discussing some of the more obscure warnings, hoping to give you a better idea as to what you should do when and if one is issued for your area. Samantha-Rae Tuthill, AccuWeather staff writer. Storm Warnings are issued for the Tidal Potomac River and the Chesapeake Bay when one or both of the following conditions is expected to begin within 36 hours and not directly associated with a tropical cyclone: 1)  sustained winds of 48 knots to 63 knots, 2) frequent gusts (duration of two or more hours) of 48 knots to 63 knots. NWS A Red Flag Warning is issued to alert fire officials and firefighters of potentially dangerous fire weather conditions within the next 12 to 24 hours. These winds may be accompanied by storm surge, coastal flooding, and/or river flooding. AND AND/OR A Flood Warning is issued when flooding is imminent or occurring. The outlook contains two segments: One segment for the marine zones and adjacent land-based (i.e., coastal) zones and the other segment for the rest of the land-based zones. An Extreme Wind Warning is issued for surface winds of 100 knots (115 MPH) or greater associated with non-convective, downslope, derecho (NOT associated with a tornado), or sustained hurricane winds are expected to occur within one hour. Gale Warnings are issued for the Tidal Potomac River and the Chesapeake Bay when one or both of the following conditions is expected to begin within 36 hours and not directly associated with a tropical cyclone: 1)  sustained winds of 34 knots to 47 knots. A Frost Advisory is issued in the spring at the start of the growing season (when it is late enough to cause damage to new plants and crops). All NOAA, Definitions of Weather Watch, Warnings and Advisories. A Blizzard Warning means that the following conditions are occurring or expected within the next 12 to 18 hours. Powerful storm likely to lash eastern US after Thanksgiving, EF2 tornado left widespread damage in Dallas-Fort Worth area, Daily coronavirus briefing: US records 2 million new cases in 2 weeks, Macy’s Thanksgiving Day Parade to march on through pandemic. It only means they are possible. A Coastal Flood Advisory is issued when minor or nuisance coastal flooding is occurring or imminent. Virtual Tour 2) wind gusts of 46 to 57 mph for any duration. When a tornado warning is issued, seek safe shelter immediately. High Wind Watch. 1) Snow and/or blowing snow reducing visibility to 1/4 mile or less for 3 hours or longer The snow/sleet criteria for a Winter Storm Warning for the five westernmost counties (Allegany, Mineral, Grant, Pendleton, and Highland) is higher (6 inches or more within a 12-hour period; 8 inches or more within a 24-hour period). An Excessive Heat Watch is issued when there is a potential for the heat index value to reach or exceed 110 degrees (east of the Blue Ridge) or 105 degrees (west of the Blue Ridge) within the next 24 to 48 hours. Contractions Dew Point ... CallUrl('www>wunderground>com