Every year hundreds of outdoor enthusiasts succumb to the effects of overexposure to extreme heat and cold. Sudden onsets of snow and ice storms trap hunters and hikers in remote areas, but also play a part in countless vehicle accidents when outdoor adventurers drive into conditions they are not prepared for. Anglers are near the top of the list of those hit by lightning each year in the U.S. Flash floods washout roads and trails in backcountry areas, and mudslides can cut off access to remote regions for long periods. These are just a few of the reasons why everyone venturing into the wilderness should check the forecast before doing so and have a means of monitoring the weather for changes.
Fortunately, there are more tools available today for keeping up to date on changing weather than there ever have been. These tools can be divided into two groups – those that provide real-time weather information from the National Oceanic and Atmospheric Administration (NOAA) and those that provide outdoor enthusiasts with basic information to assist in making a personal forecast.
NOAA Weather Radio is a network of transmitters set up around the United States that broadcast constant weather information 24 hours a day, seven days a week. There are several models of handheld GPS units and FRS/GMRS two-way radios that are able to receive NOAA information in either audio form or text in the unit display. The extent of such information can be as minimal as a weather icon indicating that a severe weather bulletin has been issued for your area or as detailed as a complete audio summary of conditions transmitted by the nearest NOAA station. There are even some GPS units that can overlay Doppler radar and weather satellite imagery over maps of your location, but such features are only useful if the person looking at the display is capable of correctly analyzing and interpreting the images correctly. The advantage to these units is that they can provide very detailed and current information. The disadvantage to the radio receivers is that there are remote areas of American wilderness not covered by NOAA transmissions and personal electronics equipped with NOAA receivers cannot be counted on to provide information 100% of the time everywhere your adventures take you.
The second group of tools you can use to monitor the weather includes devices with built-in portable weather sensors. This group would include handheld portable weather stations and personal gear, such as watches, outfitted with weather sensors. The effectiveness of these items is directly related to the amount and accuracy of information they provide. A watch with a barometer and thermometer will not be as useful as a fully equipped handheld weather station showing a dozen or more weather parameters, but some information is better than none at all.
Access to a barometer is valuable when trying to predict what the weather may do, and having a barometric pressure display that shows the pressure tendency (whether it has been falling, rising or steady for the past several hours) is especially helpful. The sharper the change in barometric pressure the greater the chance of a major change in weather with high winds. Rapidly falling pressure is usually a good indication of a major front or storm heading your way. Nature will supply her own indicators such as birds and insects flying at lower altitudes, darkening and lowering clouds, increasing winds and stronger odors when pressure falls. When you encounter these and confirm that pressure tendency in downward with a barometer, you'll know it's time to get to shelter.
Handheld weather stations can provide pressure, wind speed, humidity, wind chill factor, dew point and many more pieces of information to help construct an "in-the-field" forecast. Every piece of information gathered enhances the forecast's accuracy. Falling pressure combined with increased humidity, a dew point closing in on the air temperature and increasing wind all would point to an approaching storm or front. If you're hunkered down in a shelter waiting for a storm to let up and notice rising pressure, decreasing humidity, and a major change in wind direction, chances favor a change in the weather for the better.
Choose the methods and tools you're most comfortable with for monitoring changing weather in the field. The important thing is to remember to keep an eye on the sky and what's happening around you. Contrary to the phrase often used, weather never "strikes without warning." There are always signals about what is coming and it's up to everyone who ventures into the fields, forests and mountains to know how to read them in order to avoid becoming another statistic in a tragic news story.