climate change, education, mathematics, weather

On Misrepresenting Hurricane Statistics (H. Michael Mogil, CCM, CBM, NWA-DS*)

There’s data and there’s statistics. There’s also the misrepresentation of these.

We all know that statistics themselves don’t lie, but the people who use statistics may intentionally or unintentionally do so. A Tweet late yesterday by Eric Holthaus (@EricHolthaus) was the most recent example to catch my eye. With the Atlantic Ocean region bustling with intense hurricanes at this time, it would be easy for some people to draw an incorrect conclusion from Holthaus’ data (Fig. 1) – i.e., that intense hurricane activity is escalating. But that’s not necessarily what is happening.

While Holthaus’ initial post was misleading (and implied that NOAA data supported the trend line), it is important to recognize that the hurdat (hurricane data) values are the “best” historical hurricane data that scientists may have. However, hurdat contains known errors and omissions and is only as good as the observations that were used to generate the data set. Holthaus continued with additional comments and a link to the Geophysical Fluid Dynamics Laboratory (GFDL) suggesting that climate change was either the culprit now or would soon be the culprit – “Additional context: There was likely undercounting pre-1960. We expect more Cat 5’s in the future, if not already.”

First, research conducted by some scientists (e.g., Ryan Maue, Matt Bolton, and myself) indicates that the long-term global hurricane trend is “steady” and that hurricanes are not becoming more intense. Then, one must recognize that there has been a dramatic change in global observing and forecasting systems since the mid 19th century.

In fact, it wasn’t until the latter part of the 1800’s that hurricane warning offices were established and it wasn’t until the mid 20th century before the National Hurricane Center was created. Hurricane hunter aircraft were not employed until the 1940’s and the first weather satellite didn’t arrive on the scene until 1960. Since 1960, satellite observation systems have evolved to be highly powerful, high frequency, and high resolution observing tools (Fig. 2). These satellites can now see entire ocean basins; in earlier years, point ship and island reports were all that meteorologists had available. To say that “There was likely undercounting pre-1960,” would be an understatement.

The bottom line is that the data table and reference links offered by Eric Holthaus are misleading. Such data and associated statistics need to be viewed with a consistent (or at least a clearly stated discussion of the) data and how it was obtained. Apples must be compared to apples!

© 2017 H. Michael Mogil

Originally posted 9/19/17

* 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.

consumerism, weather

Insurance Matters – Post Irma and Post Harvey (H. Michael Mogil, CCM, CBM, NWA-DS*)

During the past two weeks, I spent many hours helping Dave Elliott and his team at WGUF-FM (98.9) radio here in Collier County, FL. Stephen Johnson (control room) and Scott Fish (101.9 – Gator Country radio, simulcast with WGUF) rounded out the team.

While my focus was weather, I also did some research and reporting on preparedness and post storm recovery matters. I also listened to discussions among our team and calls from listeners. I’d like to start sharing some these here to help Irma victims (and also those in Texas affected by Harvey).

This article will address a few hurricane-related insurance matters. Before beginning, let me note that I am not an insurance adjuster or a structural engineer. The items described here are simply to get readers to think things through before they either ignore insurance or go crazy about dealing with it. Always, get professional advice before addressing any matters involving insurance.

(1) Read your insurance policy BEFORE contacting your agent (Fig. 1). If you don’t have a clue about policy coverages and exclusions, I predict that you will get frustrated quickly.

(2) Take pictures BEFORE cleanup. Make sure you show water levels and the wrack (debris) line, tree damage, roof tiles or shingles lying on your lawn (where they fell) with your house in the background of the image. These pictures can help your adjuster piece things together long after the storm’s visual impacts disappear.

(3) Call your insurance agent, but, be prepared for long wait times. Insurance companies typically have agents available to help you. However, when the number of potential claimants becomes large, agent access can become difficult. Some companies are setting up mobile customer support centers in affected communities. Check with your insurance company, if they haven’t already e-mailed you information.

(4) Find out what you can do to mitigate further damage, even before your claim is approved. Often, putting blue tarp on a roof and covering damaged windows are encouraged. Be sure that anyone you contract with is a reliable, certified and bonded contractor. In Florida, you can contact the Florida Department of Business and Professional Regulation (850-487-1395). To report unlicensed activity, call 1-866-532-1440). In Texas, you can contact the Texas Department of Licensing and Regulation or American Contractors – Texas; however, not all contractor and building licenses seem to be listed here.

(5) File a claim with FEMA for either uninsured or uninsured losses online, or by phone (800-621-3362). While the focus is on homeowners, there is a question that should direct your application to the Small Business Administration for possible small business coverage.

I filed this morning and it takes less than 20 minutes to do this online. You can also call FEMA directly to file a claim. Even if you don’t qualify for assistance, you should still file a claim.

If you have a FEMA flood insurance policy, check the policy for filing procedures.

(6) Remember that if you don’t file a claim and do things to facilitate its successful conclusion (in your favor), the answer will always be “denied.”

I hope this helps some people get a better handle on their insurance matters in the wake of these two destructive storms. I will update this article as I come across additional insurance information.

For those in disaster areas, please take care and recover safely and quickly.

For those in any area, please think about contributing to reliable and effective charities. Remember, that after the initial rush to get utilities restored, cleanup begun, properties secured, and finding water, ice and food, people will need money to put their lives back together.

© 2017 H. Michael Mogil

Originally posted 9/15/17

* 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

Uncategorized, weather

Tropical system affecting Florida (H. Michael Mogil, CCM, CBM, NWA-DS*)

While ex-hurricane Franklin dissipated quickly over Mexico yesterday, a much weaker tropical system began affecting Florida (Fig. 1). On Wednesday, the system was located over the Bahamas and all its storminess remained well east of Florida. In fact, thanks to the dynamics of these “tropical waves,” places west of the wave (in the Northern Hemisphere) are typically afforded sunny skies.

That was the dichotomy across Florida yesterday. The wave was located across southeast Florida late in the morning. As a result, southeast Florida was under a dense cloud canopy with numerous showers and thunderstorms (Fig. 2); at the same time, southwest Florida was experiencing scattered cumulus clouds and some high-altitude cirrus clouds, blow off from the storms to the east (Fig. 3).

East of the wave, southerly wind flow at low levels was convergent (winds blowing together). This forced air to rise, and rising air often yields clouds and precipitation. West of the wave, low-level northeasterly winds were divergent, yielding sinking air and clearer skies.

As of mid-morning yesterday (Aug. 10, 2017), Fort Lauderdale / Hollywood Airport (FLL) had logged record-breaking rainfall (at least 3.36” versus the old record of 3.35” set in 2003; records for FLL date back to 1912). To highlight the variability of rainfall, nearby Fort Lauderdale Executive Airport (FXE), just 9 miles away, received a scant 0.69” during roughly the same time period.

The “tropical wave” headed westward yesterday and brought some heavy thunderstorms to southwest Florida. One thunderstorm moved from north to south across Lee, Hendry, and Collier Counties, bringing  locally rainfall amounts, of an inch to more, to the area. The storm had a very pronounced outflow boundary, with a multi-layer “shelf cloud” marking its arrival (Fig. 4).

Today, with the tropical wave remaining over south Florida, more widespread shower and thunderstorm activity can be expected. Again, rainfall amounts may be locally heavy, with ponding of water possible in usually vulnerable low-lying areas and on roadways.

© 2017 H. Michael Mogil

Originally posted 8/11/17

* 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.

oceanography, weather

A major source of a hurricane’s energy

Everyone knows something about tropical cyclones, the broad class of tropical low-pressure systems that includes hurricanes and typhoons (Fig. 1). Many of us know when and where they are more likely to form and how they are named. If you were asked about the most favorable conditions under which these tropical systems develop, among the first things you would probably say would be sea surface temperature. Some of you may also know that a sea surface water temperature above about 80oF is a very favorable factor. No wonder that hurricanes form over low-latitude ocean areas.

A hurricane or its antecedent weather system could be thought as an engine, drawing heat energy from the water body underneath it. The system does this in two ways. First, air touching warm water is warmed by contact (conduction), and air heated from below wants to rise (convection)*. Second, water evaporates from the warm ocean surface (with latent heat trapped in the water vapor) and is then carried upward by rising air currents (updrafts). The latent heat is released during the phase change from water vapor to water droplets (condensation and cloud formation) and that heat is then distributed vertically within the updraft (Fig. 2).

Now, think about a weather situation modeled in your kitchen. Imagine that you have a bowl with hot, steaming soup. Would you rather cool it down by blowing on the whole bowl or a small portion of the soup in a spoon? Almost everybody would choose the second option. Well, now think about the force of the winds in a hurricane. Don’t you think they are strong enough to lower the water temperature? And if you take also into account the large amounts of chilled precipitation that falls on the ocean surface, then you would realize that we need something else to keep providing the necessary energy for hurricanes.

The depth of the isothermal layer (a layer in the ocean that has an almost constant temperature) plays an important role in sustaining and intensifying hurricanes and tropical cyclones. Considering its depth and its temperature, we could then estimate the available potential energy for the hurricane’s heat engine. It is important to note that the hurricane circulation is strong enough and its pressure low enough to actually lift the surface of the ocean, causing deeper layers with a lower temperature to rise, thereby squeezing this isothermal layer somewhat. Depending on the strength of the storm’s circulation, how low the atmospheric pressure is in the center of the storm, and the storm’s speed of motion, the effect can be quite strong. It could possibly even generate a cool surface water “footprint.”  Obviously, such cool “footprints” can weaken a hurricane.

Conversely, we can say that there must be certain areas where a tropical cyclone could intensify. Tropical meteorologists call these “warm pools.” Forecasters can monitor these and ascertain how they affect a hurricane’s growth and/or intensification.

*Sensible heat is almost negligible, since it depends of the temperature difference between the water surface and the air, which in the tropics is usually less than 1oC ( Emanuel, K: The theory of hurricanes, 1991).

© 2017 Mayguen Ojeda

Originally posted 6/17/17

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

Extremely dangerous Nicole aims for Bermuda (H. Michael Mogil, CCM, CBM, DMS)

fig001-goes-e-eir-rainbow-161013-0745zGiven her size and strength, Category 4 (EXTREMELY DANGEROUS) Hurricane Nicole is likely to bring major impacts to Bermuda today (Oct. 13, 2016). As of 5:00 a.m. Atlantic Standard Time (A.S.T.) or 5:00 a.m. E.D.T., Nicole was located about 100 miles to the southwest of the tiny island Nation of Bermuda and was moving to the north-northeast at 15 miles per hour. According to the National Hurricane Center (NHC), Nicole is expected to be at major hurricane strength when it moves near Bermuda later today. It is easy to see how close Nicole is to Bermuda in this enhanced overnight infrared GOES satellite image (Fig. 1).

NHC’s early morning advisory notes that Nicole is a large tropical cyclone. Hurricane-force winds extend outward up to 65 miles from the center and tropical-storm-force winds extend outward up to 175 miles. With the storm already so close to Bermuda, it is no surprise that Bermuda International Airport (KTXF) has recently reported sustained winds of 43 miles per hour with a gust to 62 miles per hour.

The last Category 3 storm to strike Bermuda was Fabian on Sept. 5, 2003 (with sustained winds of 120 miles per hour and gusts to 164 miles per hour). Prior to Fabian, the most destructive storm to strike the island was back in 1926 (prior to the start of storm naming).

In addition to hurricane force winds, NHC forecasters are concerned about the following hazards for Bermuda:

  • a dangerous storm surge will raise water levels by as much as 6 to 8 feet above normal tide levels in Bermuda. The surge will be accompanied by large and destructive waves.
  • total rainfall accumulations of 5 to 8 inches through this evening.
  • swells associated with Nicole will create dangerous surf conditions and rip currents.
  • isolated tornadoes are possible on Bermuda.

Swells will also spread to the U.S. East Coast during the next few days, creating similar coastal risks of dangerous surf conditions and rip currents. Some beach erosion is also possible. With a full moon slated for Oct. 16, 2016, tides will be higher than at other times during the month. This could add to coastal flooding risks.

© 2016 H. Michael Mogil

Originally posted 10/13/16

weather

Scheduling the arrival of Matthew’s winds (H. Michael Mogil, CCM, CBM, DMS)

fig001-sfl-watch-warning-map-161006-1145amedtNational Weather Service (NWS) offices from Florida northward to the Carolinas have been publishing numerous “local action statements” and other information about Category 4 (Major Hurricane) Matthew (Fig. 1). Included are probabilities of various weather hazards, flooding maps, storm track maps and much more. Local media outlets, reliable weather bloggers, private sector weather providers and others are sharing this information. So, too, are we here at the Global Weather and Climate Center. Our bloggers / weather correspondents will also be trying to add the scientific underpinnings for some of the information.

A short while ago, the NWS Miami office provided it’s latest thinking on the timing of the onset of hurricane and tropical storm force winds across south Florida. Rob Molleda, the Warnings Coordination Meteorologist for the office, emphasized that, “these are on the earlier side and are for SUSTAINED (at least 1 minute in duration) winds. Gusts to tropical storm force (39 mph or greater) in periodic squalls will begin early this afternoon over east coast locations and over interior and western sections of South Florida starting mid-afternoon. These GUSTS are for short-duration winds, those not sustained for more than 1 minute.” This is important because some news media outlets use gusts to define the worst weather. Yet, “hurricane force wind gusts” do not mean that hurricane conditions occurred!

Period of sustained tropical storm force winds (39 mph or greater) for far south Florida locations (not including the Keys):

Palm Beach County: 3:00 p.m. Today – 8:00 a.m. Friday

Broward County: 3 PM Today – 3 AM Friday

Miami-Dade County: 3:00 p.m. Today – 1:00 a.m. Friday (most likely north and east/coastal sections)

Hendry/Glades/Interior Collier County/Lake Okeechobee: 8:00 p.m. Today – 8:00 a.m. Friday, ending earlier in Collier County

Coastal Collier County: no hurricane force winds are forecast. If storm tracks more to the west, timing of onset of hurricane force winds would be between 8:00 p.m. – 10:00 p.m. tonight, lasting through 5:00 a.m. Friday.

Period of sustained hurricane force winds (74 mph or greater):

Palm Beach County: 9:00 p.m. Tonight – 6:00 a.m. Friday

Broward County: none forecast, but potential from 9:00 p.m. Tonight – 3:00 a.m. Friday, if Matthew’s track shifts to the west.

© 2016 H. Michael Mogil

Originally posted 10/6/16

 

weather, weather safety/preparedness

Matthew heading for Florida… (H. Michael Mogil, CCM, CBM, DMS)

There’s an old expression about, “proximity.” It goes, “close, but no cigars.” That was clearly contrived in another era. However, in the case of Matthew, close may be close enough.

fig001-matthew-nhc-track-fcst-map-161005-8amedtThe latest National Hurricane Center’s (NHC) projected track for Matthew brings him very close to the Florida east coast near Jupiter Beach, FL by early Friday (Fig. 1). Given the size of the tropical force wind zone (sustained winds up to and including 73 miles per hour), which has been focused to within about 45 miles from the storm’s eye (with tropical storm force winds extending outward some 175 miles outward from the eye), many places in Florida will be very windy on Thursday and Friday. Locations closest to the east coast of Florida will be at the highest risk of hurricane force winds; many inland locales will experience tropical storm force winds.

fig002-sfl-watch-warning-map-161005-8amedtAs a result of Matthew’s closer approach to the east coast of Florida, hurricane and tropical storm watches and warnings have been posted for much of southern and eastern Florida (Fig. 2).

Don’t be misled by some TV meteorologists and news folks who prefer to focus on wind gusts. Wind gusts are not the measure of tropical storm or hurricane wind force conditions. They may be good for inciting excitement that the storm is stronger than it is, but…

The entire suite of hurricane dangers can be expected along the east coast of Florida. This includes high winds, torrential rains, coastal wave action, storm surge, beach erosion, local flooding and even a risk (albeit low) of tornadoes. Inland locations of south Florida, as far west as the north-south I75 corridor, can expect high winds. There will likely be a very significant rainfall gradient between coastal and inland locales, with the heaviest rainfall closer to the coast.

West coast Florida coastal areas can expect some rough surf and beach erosion.

Obviously, winds and waves over nearshore and offshore areas and Lake Okeechobee will make any water-based activities extremely dangerous.

In addition to state-declared states of emergency from Florida northward to the Carolinas, airlines have begun implementation of no-charge rebooking programs, especially for flights departing from east coast Florida airports. Note that some airlines will charge the current price of a ticket, not the price paid months ago (please read the fine print to be sure).

Florida Power and Light (FP & L), the state’s major energy supplier, has sent e-mail notices to its business customers advising them that FP &L was ready for the storm. No doubt, supermarket shelves will soon be stripped of toilet paper, milk, eggs, break and water. Hardware store will soon have no plywood for sale. And gas station lines have been reported as being long.

A safe rule, espoused by emergency management agencies, especially for hurricane warning areas, is to have a 3-day supply of water and non-refrigerated food on hand.

In some places along the southeast coast (particularly South Carolina) coastal evacuations are being ordered. This includes the state’s lane reversal evacuation plan to lessen gridlock. Under the plan, Interstate 26 will only allow traffic flow away from the coast. In other places, county evacuations are being urged, especially for low-lying coastal areas and/or sand bags are being provided by local government agencies.

As I have noted for the past several days, tropical cyclone forecast position errors grow with time. NHC has willingly shared its error values: around 175 miles at day 4 (96 hour forecast) and 230 miles at day 5 (120 hours forecast). Hence, Matthew could wind up being positioned anywhere within or near the “cone of uncertainty.”

With a storm, roughly paralleling the coast, even a slight shift is track can produce significant changes to expected weather and water conditions. One has only to think back to Hurricane Charley in 2004. For that event, a slight jog toward Florida’s west coast yielded a landfall just north of Fort Myers, rather the expected landfall 150-200 miles further north, near Tampa.

fig003-4-5-matthew-modle-forecasts-valid-161011-00z-8amedtLooking well into the future, where forecast errors continue to grow, Matthew has transitioned from a New England/eastern Canada landfall to one in which the storm was expected to race across the north Atlantic toward western Europe to the current scenario in which Matthew stays roughly in place off the southeast coast and returns to the Miami area later next week. This is all the result of changes in upper level wind forecasts (because upper level winds steer hurricanes). Figures 3 through 5 showcase a few of these long-range solutions (all valid for the same time – 8:00 a.m. E.D.T. on Oct. 11, 2016).

With this long-term solution scatter in mind, it’s best to key on the first five days of the forecast. Get ready if you are in a watch or warning area and stay tuned to reliable weather updates through the period of risk.

© 2016 H. Michael Mogil

Originally posted 10/5/16