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

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.

technology, weather

Rain temporarily leaves Southwest Florida (H. Michael Mogil, CCM, CBM, NWA-DS*)

The focus during tropical cyclone events is typically on high winds, coastal storm surge, heavy coastal and inland rainfall, and possible flooding. However, if one is located far enough away from the storm’s circulation, atmospheric processes may lead to less rainfall. Such is the case for southwest Florida during the past few days. And while rainfall didn’t vanish entirely from the southwest Florida area, it certainly dropped off dramatically.

Fig. 1 shows the upper level wind flow as determined by weather satellite and radiosonde (weather balloon) data. Computer programs can track cloud elements and compute their motion (and, hence, winds). Combining radiosonde wind and temperature data and infrared satellite cloud temperature measurements, computer programs can assign winds into specific altitude bands.

Late on Jun. 21, 2017, it is easy to see this altitudinal variation near Tropical Storm Cindy (located just offshore from the Texas-Louisiana coast). Winds shown in green show a counterclockwise (low-pressure) circulation. Mid-altitude winds are tagged to be between 20,000 feet to 25,000 feet above ground level or at pressure altitudes of 350mb to 500mb. Pressure is measured in millibars (mb) and decreases as one goes higher in the atmosphere (due to less air above).

To the north and east of Cindy’s mid-altitude circulation, higher altitude winds (shown in blue) actually spin slightly clockwise (indicating a high-pressure system). This differential circulation pattern is often found in well-developed tropical storms and hurricanes.

This upper-level circulation leads to a ridge or high-pressure system to the east of the storm’s circulation. In this high-pressure system, sinking air dominates. This is in contrast to the rising air motion (and associated clouds and precipitation) within Cindy’s circulation. Note that precipitation can still extend quite a distance from the storm’s center, but is mostly confined within the low- and mid-level counter-clockwise circulation pattern (Fig. 2). As a result of these upper and lower level circulation considerations, southwest Florida experienced less cloudiness and less shower and thunderstorm activity during the past two days.

As Cindy landfalls, weakens and moves to the northeast (see Fig. 2 – the elongated shape of the storm’s circulation is oriented in the direction of future movement), the upper ridge over Florida will slowly weaken and a more usual daytime shower and thunderstorm pattern will return to southwest Florida.

© 2017 H. Michael Mogil

Originally posted 6/22/17

* 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.

hydrology, weather

South Florida Rainfall Records Going Under Water (H. Michael Mogil, CCM, CBM, NWA-DS*)

A few days ago, I noted that southwest Florida “rainfall for June 2017 (now almost only half over) was at rarified levels.” Since I’ve had a chance to compare observed rainfall to longer-term records (using the NOAA Regional Climate Center data base), it is clear that the deluge so far this month has started to submerge many existing records.

Recognize, however, that many locations do not have official long-term records; hence, the numbers shown for record comparisons are limited to only a few sites. And, even for some of these, records are rather short-term. Regardless, the numbers are more than impressive across the entire region. They are even more impressive when one realizes that less than a month ago, everyone was worried about drought and forest fires!

Looking at a radar – rain gauge data mix (Fig. 1), it is easy to see where the heaviest rainfall has occurred. Collier and Broward Counties have some locations with an excess of 20 inches so far this month.

Thus far this month (through early morning on Jun.18, 2017), Naples Airport, FL (APF) has received 11.40 inches of precipitation. The average for the entire month of June is about 8.80 inches. Based on the Naples area period of record (1942-2017), the 11.40 inches ranks 17th on the list of highest monthly amounts. The record June rainfall occurred in 2005 (20.51 inches); the second highest amount was recorded in 1947 (17.97 inches).

Regional Southwest Airport (RSW) in Fort Myers has received 12.96 inches so far this month, making this the 5th wettest June at RSW (records have been kept there only since 1998). The record occurred in 2005 (20.85 inches).

With an even shorter period of record, Marco Island has already measured 20.90 inches of rain this June. The record (25.21 inches) also occurred in 2005.

Rainfall, year-to-date, at Marco Island is now at roughly 60% of the total average yearly rainfall of about 50 inches.

Given the weather pattern that we are in and the abundant tropical moisture supply, it is likely that some of these long-term records could be challenged and broken as the month continues. And, to think, there’s still 13 days left in the month!

© 2017 H. Michael Mogil

Originally posted 6/18/17

* 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

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

Description of the four-panel GWCC home page display (H. Michael Mogil, CCM, CBM, NWA-DS*)

The GWCC home page contains a four-panel graphic containing satellite and radar observations and a severe weather outlook (all from NOAA). The following is a brief overview of these graphics (organized by column from left to right):

  • GOES Enhanced Infrared satellite image (upper left) – This image, obtained by a GOES (Geostationary Operational Environmental Satellite) measures the “heat” given off by clouds, large water bodies, land surfaces, and clouds. Using a special “enhancement” scale (see color bar at the bottom of the image, just below the NOAA logo), warmer colors appear as blues and greens and colder temperatures appear as yellows and reds. Note, that GOES satellite images on different web pages (or in different GWCC posts) may use different enhancement or “false color” image temperature scales. Colorized images, such as these, should always have their own color key.
  • GOES Water Vapor satellite image (lower left) – This geostationary satellite image also measures “heat,” but the satellite sensors used are more sensitive to the amount and distribution of atmospheric water vapor. When the atmosphere at the middle and high altitudes is dry, infrared energy from lower altitudes (where temperatures are normally warmer) is able to escape to space and be detected by the GOES (Geostationary Operational Environmental Satellite) sensors. This image has been false-colored using a special “enhancement” scale: dry (black and orange), mid- and high-level moisture (white), and cloud-laden at mid- and high-levels (blue and green through red and purple).
  • Storm Prediction Center (SPC) convective outlook (upper right) – SPC issues a wide array of severe weather and other thunderstorm-related guidance and outlook products. They also issue tornado and severe thunderstorm watches and fire weather outlooks. This image, which is often updated several times a day, shows expected thunderstorm and severe thunderstorm activity for “Day 1.” “Day 1” extends from the forecast time until the next 1200 GMT (Greenwich Mean Time or 8:00 a.m. E.D.T / 7:00 a.m. E.S.T. Favored areas for thunderstorm / severe thunderstorm activity are depicted as, “to the right of a line,” as shown by an arrow at the end of any line.
  • National radar composite image (lower right) – This image brings together radar reflectivity data from some 100 plus radar sites throughout the contiguous 48 states. Radars measure how much energy atmospheric solids and liquids (hydrometeors such as snow, hail, and rain, as well as particles such as dense smoke and volcanic ash) reflect back to a radar site. The greater the reflectivity value (shown in dBz units), the greater the concentration of so-called “hydrometeors,” solids and other objects (e.g., birds, bats), the radar beam may intercept. The color scale ranges from blues and greens (the lowest reflectivities) to reds and purples (the highest reflectivities).

© 2017 H. Michael Mogil

Originally posted 4/7/17

* 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.

climate, humor, weather

Southwest Florida winter to continue (H. Michael Mogil, CCM, CBM, NWA-DS*)

BULLETIN: Four Naples groundhogs spied their shadows early Thursday morning. Hence, look for six more weeks of south Florida winter. Yahoo!

Punxsutawney Phil does not have a sterling record of furcasting the weather for the last six weeks of winter, even though the official Punxsutawney web site says otherwise. I know because an intern and I analyzed about 100 years of Phil’s forecasts in the late 1990’s. During our research, we discovered that, at best, Phil was accurate only about 10 percent of the time. Phil just kept getting it wrong…and getting it wrong…and getting it wrong, much like Bill Murray did in the movie, Groundhog Day.

Phil’s forecast accuracy is far below chance and offers stark testimony to the inability of the Groundhog legend to really offer any hint about upcoming weather. Still, the legend is fun and offers a great escape for mid-winter blues. And even with a spate of Johnny-come-lately Marmota Monax’s (Phil has many ancestors and bretheren), groundhog weather prediction simply doesn’t cut it.

One reason these groundhogs keep getting it wrong is because of media coverage. No, the furry critters aren’t creating fake news. Rather, as Al Roker noted on the Today Show, Thursday morning, there are simply too many camera lights. Hence, the only forecast possible is ongoing winter. Not surprisingly, even with cloudy skies (Fig. 1), Punxsutawney Phil saw his shadow on Thursday (Fig. 2). I didn’t even bother to see what the other nationally known groundhogs predicted. I knew the answer.

Instead, my focus was on four Naples groundhogs. Okay, so they are Ty babies™. They are still groundhogs! And I can report, unequivocally, that no camera lights were at play. It was pure sunshine that allowed these marmots to see their shadows (Fig. 3).

While folks in northern climes are dreading six more weeks of winter, we in Naples are thrilled about winter’s continuance. The reason is that in southwest Florida, winter means lovely weather. Average daily climatological temperatures start in the mid-60’s in early February and only rise into the lower 70’s by the end of March. The daily range spans about ten degrees above and below these values. In short, it’s almost like late Spring in northern states. With minimal rainfall chances, it’s the weather southwest Floridians crave.

The only drawback to the lovely weather is that southwest Florida could use a few days of steady rainfall. Southwest Florida and much of the Florida peninsula, according to the National Drought Mitigation Center, has been (and is expected to continue to be) abnormally dry.

Wherever you may live, and whatever the weather brings, please, enjoy. Summer heat and humidity, for most of us, are just over the distant horizon.

© 2017 H. Michael Mogil

Originally posted 2/4/17

* 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.