weather, weather safety/preparedness

Nate Targeting Louisiana-Northwest Florida Coast (H. Michael Mogil, CCM, CBM, NWA-DS*)

Hurricane Nate is nearing peak intensity (strong Category 1 hurricane with sustained winds of 90 miles per hour) as it races toward landfall on the Mississippi-Alabama coast tonight (Fig. 1). However, with the strongest winds and the greatest push of water toward the coast on its eastern flank, places from extreme eastern Louisiana to northwest Florida stand to take the greatest beating.

At 4:00 p.m. C.D.T., pm, the National Hurricane Center (NHC) had posted a hurricane warning from Grand Isle Louisiana to the Alabama/Florida border, Metropolitan New Orleans, and parts of the Lake Pontchartrain shoreline. NHC has also posted storm surge warnings from Grand Isle, Louisiana to the Okaloosa/Walton County line in Florida (Fig. 2).

NHC expects maximum flooding of seven to 11 feet above ground level is expected in portions of southeastern Louisiana and along the Mississippi coast. A similar surge (or greater) could affect parts of Mobile Bay and the rivers that feed the Bay from the north, as well (Fig. 3). Note that surge values are for locations at or near the interface of land and water. The surge can extend across inland locations, but its depth will be tempered by how much the elevation rises. As a result, there may be significant variations of storm surge depth across small distances.

While sustained winds are expected to remain at category 1 levels as the storm makes landfall, it is the push of water onto the land, the dreaded storm surge, that is, perhaps, the most ominous part of the forecast.

Several factors are at play this evening and overnight.

First, the storm is expected to push water across coastal areas from extreme eastern Louisiana to the Florida panhandle. However, Mobile Bay, with its relatively wide Gulf opening (even with barrier islands and peninsulas offering some protection), narrows to a small region just east of Mobile, where several low-lying rivers occupy a broad flood plain. This region lies in the path of the expected surge.

Meteorologists and other scientists know that when a fluid is constrained horizontally, it must rise vertically. This means that a 10-foot coastal surge could grow many feet as it moves northward through Mobile Bay, before it reaches the city of Mobile and the rivers to the north and east of Mobile.

The fast forward speed of the storm will also enhance the push of water onto land.

And, it now appears that the storm will be making landfall close to the time of high tide (shortly after midnight C.D.T.).

Add heavy rainfall, a large area of tropical force winds well inland, and the risk for tornadoes (mainly on the eastern side of the storm’s path) and a large swath of the southeast and middle Atlantic can experience stormy conditions during the next 48 hours.

There are numerous web sites, TV station meteorologists and NWS forecasters that have been sharing (and are continuing to share) needed weather safety information in the face of this tropical onslaught. If anyone reading this article is located in high or moderate risk areas associated with this storm, your window of opportunity to take action is rapidly narrowing. Get to a safe place (above expected storm surge levels) quickly.

© 2017 H. Michael Mogil

Originally posted 10/7/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

Dangerous Irma Targeting Naples (H. Michael Mogil, CCM, CBM, NWA-DS*)

As of late yesterday afternoon, downtown Naples, U.S. Highway 41 (Tamiami Trail), and Naples/Collier County beaches resembled a ghost town. One could drive down Gulfshore Boulevard (a thoroughfare about a block or so from the beach) and perhaps see one or two cars. Fig. 1 shows the scene sans vehicles.

It was eerie.

But there was good cause for the lack of humankind. After a week of Hurricane Irma track uncertainty across the state of Florida (the large-scale storm track was “spot on;” the details across Florida, not so), computer and human thinking centered on a track along the west coast of Florida. Now, early Saturday morning (Sept. 9, 2017), the expected storm track is actually slightly west of Naples (i.e., with the center remaining over water). This is reminiscent of Donna (which destroyed the Naples Pier in 1960) and Charley (which slammed into Punta Gorda, north of Fort Myers in 2004).

This sets the stage for a worst-case scenario for Collier and Lee Counties.

Specifically,

high winds – much of Collier and Lee Counties will be impacted by triple digit sustained winds because the eye wall will be passing directly over both counties. Wind gusts can easily reach speeds that are 20 percent higher than sustained winds. Even though Irma has weakened slightly this morning (due in part to interaction with topography across Cuba), reintensification is expected later today (once Irma leaves Cuba).

heavy rainfall – since the right side (i.e., the wet side) of the storm will be affecting the two counties, roughly eight to 12 inches of rainfall (with locally higher amounts) is anticipated. Given recent heavy rainfall and flooding, these two-day rainfall totals may help replicate the recent flooding.

tornadoes – again the right side of the storm (mainly, the leading front right quadrant) is where tornadoes are most likely to form. That storm quadrant will be passing directly over Collier and Lee counties during the day on Sunday. Fortunately, most hurricane-generated tornadoes are weak and short-lived.

storm surge – is not an instantaneous (or wall-like) rise of water. Rather, it is the relentless onslaught of waves pushing water onshore, without the corresponding opportunity for water to flow back to the ocean. As a result, water levels can rise and push far inland.

Clearly storm surge will be a major risk for many areas. With a storm center over land, Naples and Fort Myers would not receive as much of an initial surge; with a storm offshore, an initial surge from the south is likely. Under either scenario, as the storm moves north of Collier and Lee Counties, hurricane force westerly winds will push additional salt water onto land areas for a longer period of time. Expected surge values will be in the six to 12 feet range.

High tides can add to the expected storm surge. Unfortunately, the turn to westerly winds will be occurring near the time of high tide (about 4:00p.m. E.D.T. on Sunday). Note that expected surge height values do not include any waves that may occur during the time of the storm surge.

Large areas of Collier County (and lesser areas in Lee and other west coast counties) are in the high surge flood risk. The map in Fig. 2 shows at surge risk areas due to a CAT 2 hurricane. Generally speaking the highest risk areas are south and west of State Highway 41.

This is a very large and very dangerous hurricane, one that can cause extensive damage to structures, trees, power lines and signs.

Since it’s too late to evacuate the area, it’s best for local residents and visitors to take shelter in sturdy structures or county-operated storm shelters. People living in mobile homes or manufactured housing should definitely leave these well in advance of the hurricane’s arrival.

© 2017 H. Michael Mogil

Originally posted 9/9/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

Getting Ready For A Hurricane and more… (H. Michael Mogil, CCM, CBM, NWA-DS*)

There are plenty of “to do” lists out there addressing what to do to prepare for a hurricane, undertake during a hurricane, and address following a hurricane. Some of the more detailed lists can be found at the following web pages:

Weather Ready Nation

FEMA – Hurricane Harvey

American Red Cross

• Your local TV stations (if you are in hurricane country)

At each of these, be sure to look for sub-page links that may provide even more detailed information. FEMA’s – Hurricane Harvey web page (found under the main page “Navigation” menu bar) provides considerable tailored information specifically for Texans. Look for a similar FEMA (Federal Emergency Management Agency) page to surface as Irma starts impacting the U.S. The Red Cross web site includes information about many topics, including how to locate loved ones who may be within a disaster area. In addition, many local TV stations distribute hurricane guides (Fig. 1), tracking charts and other informational items via local supermarkets and drug stores.

Today, I’m going to expound upon these lists a little, providing some insights as to WHY certain things are recommended. I’ll also add a few “out the eye wall” ideas. Note that no list can be totally inclusive.

Regardless of what you read or hear, hopefully, you’ll employ common sense and logic to your actions. Also, be sure you get your information from reliable sources. It’s at times like these that well-thought out plans need to be put into play. And remember that governmental and volunteer service organizations may not have the resources or the capabilities to assist you for days, maybe even weeks, after a major hurricane strike.

• If you don’t have an emergency kit, create one. It should include items that can be placed in heavy duty, sealable, freezer storage bags. Group items to facilitate finding what you may need. For example, you might have individual, labeled, plastic bags that contain medical records, medicines (may not able to refill after the storm), identification (e.g., passports, birth certificates), small denominational cash (ATM machines may not be working, if power loss occurs), cell phones and electronic appliances (sealed to keep out water) and even food and snacks (to avoid contamination with ground water). If possible, put these smaller plastic bags into larger sealable plastic bags or sealable containers.

• Although many companies (e.g., banks, credit cards, utilities) may work with you after the storm to accept late payments (without late fees), it’s just easier to make payments in advance.

• You will want to ensure that certain food items are refrigerated and/or frozen even if you lose power. One way is to ensure that temperature settings in both fridge compartments are set as low as possible BEFORE the storm strikes. If you have created frozen plastic soda or water bottles or sealable containers/freezer bags in advance, these can be used to chill the refrigerator or freezer compartments. Large chunks of ice stay colder longer than bags of individual ice cubes.

Another way is to cook some of the frozen food beforehand. It will be easier for cold hamburgers to survive, for example, than to keep ground beef frozen.

• The same chilling factor can be said for your home. Chill your home as low as possible before power is lost so you’ll have at least a slightly more comfortable environment for a longer period of time.

• Stock up on non-perishables. This includes water, crackers, nutrition/energy bars, breads, cereals, pretzels, chips, snacks, chocolate (my favorite), canned food (e.g., tuna fish), peanut butter (doesn’t require refrigeration), and even astronaut food (possibly available at a local science store). Don’t forget toilet paper, tissues, paper towels and plasticware.

• Speaking about toilet paper, be sure to fill a bathtub or two with water to help with toilet flushing.

• If you lose power and want hot water for coffee, hopefully you’ll have an accessible natural gas line or propane canister. We have a small camping stove and some small propane canisters that we plan on using in an outside location, if needed.

• If you have power banks or power sticks, be sure these are fully charged before the storm strikes. These low-cost power supplies can help power smaller appliances during power outages. Be sure your appliances are fully charged in advance, too. If you have an emergency generator (note that many condo associations don’t allow these), be sure it is charged and/or you have fuel available.

• Bring any lose or liftable objects indoors. This includes hanging or potted plants, patio furniture, trashcans and toys.

• DON’T use any type of tape to protect windows. Most tapes are not strong enough to prevent glass breakage or shattering. Even if you aren’t in a flood zone, consider the flooding potential. Move valuable or important objects, non-refrigerated or non-frozen foods, furniture and electronics to higher levels in your home.

• If you need to evacuate (either by car, mass transit or plane), consider doing this during daylight hours. It is easier to see roads, obstacles and other vehicles, especially if you wind up on local roadways. Be careful of evacuating into the projected path of the storm. You might wind up leaving a secure structure only to stay the night in a less structurally secure motel or other building (or find yourself stuck on clogged roadways).

Also, turn off gas lines, water lines and electricity before leaving.

If you can’t evacuate (or chose not to), then plan to “hunker down,” hopefully in a safe place (e.g., non-flood zone) and with neighbors or relatives. Be sure to move your car to higher ground (away from trees and power lines), if possible.

• If you are elderly, or are in a senior facility, moving out of a flood zone early is better than waiting. Several such facilities in the Houston area failed to evacuate and were flooded, putting the elderly patients at risk.

• Before the rains arrive, consider cleaning roof gutters and downspouts to facilitate the moving of water away from your home. If there are storm drains near your home, take a few moments (even it’s not your responsibility) and clean out any leaves, twigs and other debris), to enable faster drainage.

• If you have kids or pets and evacuate (and you know that pets are welcome at the evacuation center), think about bringing games, toys, books and other items that can add fun and psychological stability to the situation.

• And, just in case, think about board games, cards, and jigsaw puzzles as things to do to pass the time in a potentially non-electrical home universe. This list is long and getting longer. I will be updating it periodically, including valuable suggestions that may come from my readers. In advance, thanks for your comments and feedback.

© 2017 H. Michael Mogil

Originally posted 9/5/17

weather, weather safety/preparedness

More Naples, FL area wildfires (H. Michael Mogil, CCM, CBM, NWA-DS*)

Late Thursday, Apr. 20, 2017, two wildfires of unknown origin broke out in the Golden Gate Estates area of east Naples, FL. Although fire fighters jumped into action quickly, dry and windy conditions allowed the fire to spread. By this morning, the combined blazes had grown to about 2,500 acres.

Collier County Emergency Management issued evacuation orders for some limited areas yesterday and expanded areas affected during today. As of late this afternoon, the boundaries of the evacuation area extended from the south side of Golden Gate Boulevard south to the east-west portion of I-75 and from Collier Boulevard east to Wilson Boulevard.

Jim Dickey, WZVN-TV (CH 7 – ABC, Fort Myers) Certified Broadcast Meteorologist, posted radar imagery at around 10:00 a.m. E.D.T. today of the dual fires at his Twitter page (@WxDockey). Dickey noted that “Now that A.M. inversion has lifted, smoke plumes from #30thStFire and #FrangipaniFire visible on radar” (Fig. 1).

     Images from the Immokalee Fire Control District showed the scope of the fires and their associated large billowing smoke clouds (Fig.2 and Fig. 3). Overnight and during Friday morning, the smoke reached the Naples City limits, lowering visibility at the Naples Airport (KAPF) to 3 miles. Based on the trajectory of the plume this morning (WZVN-TV radar imagery and video), and the fact that the smoke plume is still showing up on the Miami National Weather Service radar late this afternoon, most of western Collier County (including the city of Naples) and parts of southern Lee County are going to be experiencing smoky conditions through tonight and into early Saturday morning.

Thus, smoke from the fire will be affecting many more people than the fire itself. Small airborne particles from the fire may lead to respiratory problems, even for healthy people. Check out Fig. 4, a wildfire poster from http://www.ready.gov, republished by Florida Health. It contains some useful tips for dealing with smoky air.

© 2017 H. Michael Mogil

Originally posted 4/21/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

The winds win! (H. Michael Mogil, CCM, CBM, NWA-DS*)

Today through tomorrow evening, large areas of the Nation and some nearby ocean water areas are under various types of wind warnings. From hurricane-force wind warnings in New England’s offshore waters (large-scale winter storm and intense pressure gradient) to Santa Ana (canyon-channeled) winds in southern California (Fig. 1), the winds win!

In New England, for added measure, heavy snow and bitter cold will add to the misery. Across parts of west Texas, a wintry mix will develop. In the mid-Atlantic, it’s a combination of large-scale vertical mixing (high speed winds from higher altitudes mixed down to the ground) and the effects of downslope winds.

In all of these land areas, winds will be high enough to affect the travel of high-profile vehicles and even passenger cars. Offshore from New England, waves will build to heights of more than 30 feet. As noted in National Weather Service marine warnings, “seas are given as significant wave height…which is the average height of the highest 1/3 of the waves. Individual waves may be more than twice the significant wave height.” Hence, if a 60-foot wave does form, it would take on the scope of the self-proclaimed “George Clooney Memorial Wave” in “The Perfect Storm” movie.

Winds will die down in many locales by Tuesday, as a more tranquil weather pattern establishes itself. Until then, drive safely, act cautiously, and stay in safe places.

© 2017 H. Michael Mogil

Originally posted 2/12/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

One New England Blizzard…Two New England Blizzards… (H. Michael Mogil, CCM, CBM, NWA-DS*)

On Feb. 9, 2017, southeastern New England experienced a significant snowstorm. Within the storm’s circulation, blizzard conditions lasted for some three to almost six hours and affected many areas. The National Weather Service (NWS) Office in Taunton, MA summarized the storm in a lengthy weather release on the evening of Feb. 9, 2017. Excerpts from that release have been provided here (all times Eastern Standard Time).

The storm responsible for the blizzard (Fig. 1 – left) was a “meteorological bomb,” a storm that undergoes rapid pressure falls (or “explosive deepening”) of at least 24 millibars (0.71 inches of mercury) in 24 hours. Bombs typically contain some “thundersnow,” which often means locally heavier snowfall. This bomb was no exception.

First, it’s important to reiterate what a blizzard actually is. According to the NWS, a blizzard involves falling and/or blowing snow, sustained or frequent wind gusts of 35 miles per hour or more and visibilities frequently reduced to less than a quarter of a mile. All of these conditions must last for three hours or more.

For purposes of this summary, the NWS meteorologists used only official airport reporting stations (since all of the above weather conditions are routinely reported at these). For visibilities, they decided to use reported values of one-quarter mile or less since, “…that is quite low for an automated sensor to detect.” Obviously, blizzard conditions occurred elsewhere across the area.

  • Providence, RI wins the competition with 5 hours and 18 minutes of blizzard conditions (10:51 a.m. to 4:09 p.m.).
  • Hyannis, MA was a close second with 5 hours and 4 minutes (12:56 p.m. to 6:00 p.m.).
  • Boston, MA netted blizzard conditions for 4 hours and 34 minutes (12:20 p.m. to 4:54 p.m.).

Other locations reporting blizzard conditions (in decreasing length of time of blizzard conditions) included Martha’s Vineyard, MA; Block Island, RI; Beverly, MA; Marshfield, MA; New Bedford, MA; and Westerly, RI.

As the region digs out, another storm system looms on the western horizon. This one, much like its predecessor, promises to involve “explosive deepening” as it passes by the region from late Sunday into late Monday (Fig. 1 – right). However, its movement will be significantly slower, allowing heavy snowfall and blizzard conditions to last longer. Already, local snowfall forecasts are pegged at approaching two feet.

This will be a “hunker down” storm. So stay home, dress in layers if you venture out, and, unless you have a snowblower, consider letting a local teenager shovel your driveway.

© 2017 H. Michael Mogil

Originally posted 2/11/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

Long duration lake-effect snow event underway (H. Michael Mogil, CCM, CBM, NWA-DS*)

The National Weather Service has issued “lake effect” snow warnings and advisories for areas to the east of Lakes Erie and Ontario through Sunday evening (Fig. 1). These forecasts call for locally heavy snow and wind-blown snow with associated hazardous driving conditions. Forecasts for areas in New York State downwind of these lakes indicate that snowfall amounts will be within a 15 and 40 inch range (locally higher amounts expected) along with wind gusts to 45 miles per hour. The heaviest snowfalls are expected in the Tug Hill Plateau area (downwind from Lake Ontario, near Watertown and Montague, NY), with 12-hour snowfalls, throughout the period, frequently in the six to 12 inch range. Already, early this Friday morning, Watertown reported wind gusts in excess of 40 miles per hour.

While not yet issued, look for similar forecasts to be posted for other downwind areas of the entire Great Lakes region during the next several days.

This entire weather scenario is linked to a quasi-stationary surface and upper air low-pressure system across eastern Canada (Fig. 2). The system’s counter-

clockwise circulation will send winds across the Great Lakes, mostly from a west to northwest direction.

With the Great Lakes mostly ice free (Fig. 3), colder air, moving over relatively warmer water, can gain heat and moisture. This allows clouds (often low-topped) to develop in bands across the lakes (Fig. 4). As these bands make landfall, the air they are riding on experiences increased frictional drag

(friction is higher as winds blow over land than water). The result is a low-level convergence effect, adding uplift to the clouds. In areas where terrain increases inland, there is an added orography-lift effect (e.g., the Tug Hill Plateau area). In a snowfall event earlier this winter season, parts of the Tug Hill Plateau were targeted with over four feet of snow in a three-day period.

Due to the nature of “lake effect” snow events, the National Weather Service in Buffalo, NY noted early this Friday morning that, “…in lake effect snow, the weather can vary from locally heavy snow in narrow bands to clear skies just a few miles away. If you will be traveling across the region, be prepared for rapid changes in road and visibility conditions.”

© 2017 H. Michael Mogil

Originally posted 1/27/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

Enhanced severe weather threat for southeast U.S. (H. Michael Mogil, CCM, CBM, NWA-DS*)

Batten down the hatches (and be prepared to take shelter today and tonight) if you live or are traveling across the southeast U.S. The Storm Prediction has issued a highly unusual severe weather outlook for the region – calling for a moderate to high severe weather risk for South Carolina, Georgia, a small part of southeast Alabama and much of northern and

central Florida (Fig. 1). According to news reports, the storm system behind today’s severe weather threat has already claimed the lives of at least six people across Mississippi and Georgia.

Fig. 2 and Fig. 3 show the radar and satellite images, respectively, late this Sunday morning. What is most telling is that the current strong thunderstorm activity is occurring in a region of dry air aloft (the oranges and blacks on the water vapor satellite image – Fig. 3). This means that rising air

inside the thunderstorms must be moving at very high velocity to counter this dryness. Hence, many of the stronger thunderstorms are already likely acting as “supercells (isolated storms ahead of a line of storms).” Two apparent supercells can be seen in the northern Gulf of Mexico (Fig. 2).

As a new low-pressure system develops across the southeast today, and moves to northern Georgia and eastern Tennessee by tonight,

(Fig. 4), a very strong jet stream aloft (winds greater than 130 miles per hour) and a very warm and unstable air mass (dew points above 70 degrees F) will all be factoring into the storm evolution as the day and night progress.

The local storm potential graphic (Fig. 5) indicates just how strong the storms may be, even removed from the main threat region.

As the newly forming low develops, it will move to the northeast and spread a large shield of rain along the entire east coast during the next several days. Except for parts of New England, the atmosphere is just too warm for snow.

Although winds will be strong across the southeast today, coastal wave action, higher than average tides,

rip current danger and other coastal and boating dangers (including offshore gale warnings in the Gulf of Mexico) will be the watchwords across the west coast of the Florida peninsula into the Gulf beginning tonight and continuing until Tuesday (Fig. 6). That is because strong west and northwest winds will arrive once the cold front clears the area (Fig. 4).

Although skies may be sunny to partly cloudy across much of the Florida peninsula now, conditions will rapidly deteriorate during the latter part of the calendar day and early Monday morning.

Stay tuned to the National Weather Service, local broadcast media outlets and any tailored private weather subscriptions you may have for watches, warnings and advisories.

If you have loose objects outdoors, consider bringing these inside before the storms arrive.

© 2017 H. Michael Mogil

Originally posted 1/22/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

weather, weather safety/preparedness

Ground fog! (H. Michael Mogil, CCM, CBM, NWA-DS*)

Dense fog advisories (Fig. 1) as well as the fog they describe (Fig. 2), covered southwest Florida early this Friday morning (Jan. 6, 2017). Some places had 0-0 visibility (that is, zero feet both horizontally and vertically); other places had visibilities of several miles horizontally and several hundreds of feet vertically (Fig. 3). Visibility is defined as how far one can see cloud bases (vertically) or known ground-based objects (horizontally).

   

It is the variation in fog thickness horizontally (and associated visibility) that came to the forefront this morning as I walked my dog, Pepper, around our southwest Florida neighborhood.

  

First, looking up my street, visibility was about a half mile, the measured length of my street (Fig. 4). As soon as Pepper and I walked onto the golf course, fog density increased and visibility decreased (Fig. 5). As we approached the location of my COCORAHS (Community Collaborative Rain Hail and Snow Network) rain gage, which is adjacent to a large pond, the fog density increased further and visibility tumbled down to a few hundred feet (Fig. 6). All images were taken within 10 minutes of one another.

These three scenarios are described in the table below:

Location Fog density Visibility
Street light ½ mile
Golf course dense ~ ¼ mile
Near pond very dense few hundred feet

For the street, warmer air temperatures resulted in less dense fog. Over the golf course, temperatures were slightly cooler, allowing for somewhat dense fog to develop. In the pond area, cooler air temperatures and higher atmospheric moisture contributed to the densest fog.

Note that these conditions contribute to the formation of fog. But, local winds, drainage winds, and other factors can allow fog areas to move. Not surprisingly, this can result in highly variable fog density along roadways. Common sense dictates that motorists of all types of vehicles (cars, buses, trucks) drive more slowly and pay even greater than average attention to potentially rapidly changing visibility.

While the dense fog has lifted already, it will be back again, especially during the upcoming winter months.

– – – – –

© 2017 H. Michael Mogil

Originally posted 1/6/17

* The National Weather Association Digital Seal (NWA-DS) is awarded to individuals who pass stringent meteorological testing and evaluation of written weather content. H. Michael Mogil was awarded the second such seal and is a strong advocate for its use by weather bloggers.

 

weather, weather safety/preparedness

Chilly wind chills for south Florida (H. Michael Mogil, CCM, CBM, DMS)

Once a strong Pacific cold front barrels through south Florida later today, attention will shift to windier weather and much chiller temperatures. The combined effect of wind and temperature will contribute to unusually low wind chills for the area. Wind chill is a measure of heat loss from exposed skin.

For Friday morning, wind chills across south Florida will range from the mid 40’s in more northern inland locales to the lower 60’s along southeast and southern locations (Fig. 1).  By Saturday morning, wind chills from Collier County northward, along the west coast, will likely dip into the 30’s and lower 40’s. The combined effect of nearby warm Atlantic waters and a northerly wind flow across Lake Okeechobee (whose waters are still quite warm) will keep East Coast southeast inland locations mostly in the mid 40’s to near 60 degrees (Fig. 2).

Then the chill vanishes, almost as quickly as it came.  Winds will quickly turn to east and allow warmer, more humid air from over the Atlantic to move back into the area. Hence, by Saturday afternoon, many western areas of southwest Florida will see temperatures skyrocket into the mid 70’s.

As noted in yesterday’s post, for the fireworks and other outdoors activities on New Year’s Eve, look for temperatures across southwest Florida to fall back into the mid to upper 60’s with light (5 to 10 mile per hour) southeasterly winds.

© 2016 H. Michael Mogil

Originally posted 12/29/16