Category: Tropical Weather

A cold front is the major weather-maker today as it settles into the Southern Plains and Southeast. The front will continue to push through the Southern Plains on Monday producing additional showers and thunderstorms. The main threat for those storms will be gusty winds, hail and heavy rain. As the front stalls out across the Southeast over the next few days, it will have ample opportunity to create showers and storms with the possibility of heavy rain, wind, and possibly some hail. This is not to say that showers and thunderstorms are expected the entire time, as cloud cover and dry air will both remain in place nearby. So watching for when energetic disturbances move into those regions will be key for storm initiation. One such disturbance looks to push through today in Texas while an upper level low serves as a center for storms on Monday in the Southeast.

Meanwhile, in the tropics there are a few areas that bear watching. The strongest is in the Atlantic Ocean as Tropical Storm Ida continues its northwestward movement at 17 mph. As an area of high pressure strengthens to the north of Ida, it should slow down the storm’s forward motion and models indicate that it may become stationary as well. Ida’s low-level center remains exposed because of the westerly shear. This shear is expected to weaken in the next day or two, allowing for the possibility of strengthening. However, the shear is expected to pick back up as an upper level trough helps to increase it. This may stall or even decrease the intensity of the storm. Another area of interest in the Atlantic resides about 325 miles east of northeast Florida. Because it is not showing signs of being tropical or even subtropical, the reconnaissance mission into the storm that was scheduled for today was canceled. The storm resides in an area that is not conducive to development while its low level center remains exposed. All of these factors give low tropical formation chances within the next few days.

In the Eastern Pacific, an area of storms located west of the Baja Peninsula has been tagged as Tropical Depression Sixteen-E. As it moves north-northwestward at 14 mph, it looks to enter an area less conducive to development tonight with cooler waters and strong upper level winds. It will also spread heavy rain into the Baja Peninsula and northwestern Mexico today and into portions of southern California and Arizona on Monday and Tuesday. Once again, be aware of flash floods and mud slides in mountainous areas of Mexico and the Southwest.

In the Central Pacific, Tropical Depression five-C continues to battle shear on its western side, shifting all the convection to the eastern side and exposing the low level center. The depression is moving toward the north-northeast and is expected to increase its speed today as steering flow increases. As it moves along its track, a shift from a northeastward movement to more northward and then northwestward movement is expected as it gets caught in the upper level pattern. Some model disagreement occurs with the intensity of the storm itself, but it is expected to increase in intensity from a tropical depression to a tropical storm later tonight, even as shear increases. However, the system should transition into an extratropical storm over the next 2-3 days. Tropical Storm watches and warnings are in effect for some of the Central Pacific islands located well to the west of the Hawaiian Islands.

Drought conditions persist across the Western United States, in some places the drought is extreme. Because of the dryness, along with lightning from thunderstorms among other causes, wildfires have been sparked all over the region. A few wildfires have burned property including the well-known “Valley Fire” in California, which has even claimed lives.

Some welcome relief was also seen this past week as a low pressure system and cold front moved onto the United States from the Pacific Ocean. This produced rainfall from the San Francisco Bay Area northward to Washington State. A report detailing the fire situation quoted an official with Cal Fire saying, “Crews have made continued good progress on several fires burning in California. A little bit of rain has helped along with cooler temperatures and higher humidity.” Of course, as a cold front pushes through an area where a wildfire is ongoing, forecasters and firefighters are also aware of increasing winds and wind direction changes that may help to spread the fire even further.

Elsewhere, as we get into the climatological peak of hurricane season, the tropics are becoming active again. In the Atlantic there are three areas that are being monitored. Tropical storm Ida is centered a little more than 1100 miles west of the Cape Verde Islands and is moving west-northwest at 14 mph. It has maximum sustained winds at 40 mph. Ida should remain a tropical storm for the next few days while crossing the Central Atlantic.

A little farther to the west. Tropical Depression Nine dissipated late Saturday afternoon. Conditions are not favorable for the storm to redevelop over the Central Atlantic. The third area being watched is an area of disturbed weather a few hundred miles off the Southeast coast.. There, conditions are marginally favorable for tropical development during the next few days. The system should move off tho the northeast, staying off the East Coast, with some strengthening possible.

In the Eastern Pacific Ocean, an area of disturbed weather located about 275 miles south-southwest of the Cabo San Lucas, Mexico is being monitored for development. Some development is possible over the next few days, but the main threat from this system will be heavy rainfall across northwestern Mexico and southern portions of Arizona and California as the system moves toward the north-northwest.

In the Central Pacific Ocean, Tropical Depression Five-C is centered about 360 miles northwest of Johnston Island, moving toward the north-northeast at 15 mph. Top winds are near 35 mph, and some strengthening is possible over the next day or two. After that, gradual weakening is expected as the system moves across open waters.

A tropical system is expected to threaten the United States late this weekend and early next week. Unlike the past several days however, the state that is threatened is Hawaii, not Florida.

Hurricane Ignacio was centered about 550 miles east-southeast of Hilo, Hawaii at 2pm HST, moving toward the northwest at 9 mph. Maximum sustained winds were near 135 mph, making Ignacio a Category 4 Hurricane on the Saffir-Simpson Scale. Ignacio is expected to continue on a northwesterly track for the next few days, passing about 150 miles northeast of Hawaii Monday and Tuesday. It should gradually weaken as it approaches Hawaii.

A tropical storm watch has been issued for the Big Island. Although Ignacio will remain offshore, since it is a large storm, tropical storm force winds may impact the Big Island Sunday night and Monday. Heavy rainfall is likely, especially on the windward side of the islands, with totals of 3-6 inches possible.

Ignacio isn’t the only tropical system being monitored in the Pacific. Hurricane Kilo and Hurricane Jimena are both over open waters.

Kilo is centered about 400 miles west of Johnston Island, moving toward the west at 13 mph. It rapidly intensified Friday night and now has top winds near 125 mph. Some additional strengthening is possible over the next 24-36 hours as it turns more toward the northwest. Kilo should cross the International Date Line early next week, at which point it will be referred to as Typhoon Kilo.

Hurricane Jimena remains a powerful system in the Eastern Pacific with maximum sustained winds near 140 mph. As of 2pm PDT Saturday, Jimena was centered about 1300 miles west-southwest of Cabo San Lucas, Mexico, moving toward the west-northwest at 9 mph. Jimena is expected to continue on  this track for the next few days with some fluctuations in intensity possible. Jimena is not a threat to land at this time.

To the north, a storm system that is not tropical in nature is bringing heavy rain and very strong winds to the Pacific Northwest. Up to half an inch of rain has fallen in western portions of Washington, and another 1-2″ is expected through Sunday. The rain is welcome news as dozens of wildfires continue to burn across the state, and any rainfall will assist the firefighting effort. What’s not welcome are the strong winds the storm is producing. Sustained winds of 30-50 mph have been reported, with gusts to 80 mph or higher.

Sustained #wind of 79 mph, with #gust to 87 on #DestructionIs. off #WA. #Coast. Fitting name for it. #wawx #windstorm

— NWS Seattle (@NWSSeattle) August 29, 2015

With the rain will come much cooler temperatures, which will also be welcome after a record-hot summer. Snow levels will drop to 8000 feet in the area, with several inches of snow possible across the higher peaks of the Cascades.

In the Atlantic, Tropical Storm Erika degenerated into an open wave earlier on Saturday. The combination of wind shear and the mountainous terrain of Hispaniola ripped the circulation apart. However, Erika’s story may not be over yet. What’s left of Erika will pass near or just south of Florida tonight and Sunday, bringing heavy rain and occasionally gusty winds to parts of Florida and Cuba. After that, it should move into the eastern Gulf of Mexico and turn more toward the north. Conditions should be more favorable in this region, and Erika could regenerate into a Tropical Storm early next week. Whether it redevelops or not, rainfall totals of 2-4 inches are expected across much of the Sunshine State through early next week. Flash flood watches are in effect for much of the region.

Well to the east, a well-defined tropical wave moved off the coast of Africa on Saturday. Conditions are favorable for development of this system, and it could become a tropical depression on Sunday. This system should head on a northwesterly track towards the Cape Verde Islands while slowly strengthening over the next few days.

After bringing gusty winds and flooding rains to portions of the Lesser Antilles, Virgin Islands, and Puerto Rico, Erika is passing south of Hispaniola this afternoon. As of 2pm EDT, Erika was centered just off the south coast of the Dominican Republic, and still stubbornly heading westward at 16 mph.

Erika remains weak, with maximum sustained winds near 50 mph. Strong wind shear and its proximity to the mountainous terrain of the Dominican Republic are keepING the storm weak.

For several days, computer models have been forecasting Erika to turn toward the west-northwest and eventually northwest, around a ridge of high pressure anchored over the central Atlantic Ocean. Erika has defied the models, and continues moving toward the west. As Erika nears the western edge of the high pressure ridge, and a trough of low pressure enters the Gulf of Mexico, Erika should finally start to turn more towards the northwest over the next 24 hours. Eventually, a turn toward the north should happen, bringing Erika closer to the state of Florida. Since Erika has traveled much farther to the west than anticipated, the risk to the Southeast has been greatly diminished. The main question now is – what part of Florida is at the greatest risk?

Most of the models are now showing a threat to the Gulf Coast of Florida. However, most of these models also show Erika spending a lot of time over parts of Hispaniola and/or Cuba. Tropical systems depend on warm water (over 26 degrees C) to maintain their strength. A track over land could result in the dissipation of Erika before it even reaches Florida. Of the models that do keep the circulation of Erika intact, most of them keep it at tropical storm strength. As a result, it appears as though the biggest threat to Florida would be heavy rainfall and flooding. This is both good and bad, depending on which part of Florida you are talking about. Much of South Florida is in a severe drought, so rainfall would be welcome across the area. Meanwhile, the west coast of Florida, especially near Tampa Bay, has seen severe flooding and record rainfall this summer, so additional heavy rain would not be welcomed.

Erika has also produced flooding across portions of the eastern Caribbean. Over 12 inches of rain was reported in Dominica, with devastating flooding resulting in at least 12 deaths on the island. Across Puerto Rico and the Virgin Islands, which have also been in a severe drought this year, rainfall totals were mainly under 2 inches. Erika did produce strong winds across the region, however. Some of the highest reported winds were as follows:

Elsewhere in the Atlantic, a tropical wave will move off the coast of Africa this weekend, and conditions could be favorable for it to slowly develop as it makes its way across the ocean.

The Pacific, especially the Central Pacific, remains active. Tropical Storm Kilo is centered about 160 miles west-northwest of Johnston Island, moving toward the west at 10 mph. Maximum sustained winds are near 70 mph, and additional strengthening is expected. A tropical storm warning is in effect for Johnston Island, but conditions should start to improve over the next 12-24 hours as Kilo pulls away. Kilo is expected to turn more towards the northwest and strengthen into a hurricane as it heads across open waters towards the International Date Line.

Hurricane Ignacio is centered about 840 miles east-southeast of Hilo, Hawaii, moving toward the west-northwest at 10 mph. Maximum sustained winds are near 90 mph, and some additional strengthening is expected over the next 24-36 hours. After that, Ignacio should start to weaken and continue west-northwestward. The current track brings Ignacio just north of the Hawaiian Islands early next week. Residents of Hawaii should monitor Ignacio’s progress this weekend.

In the Eastern Pacific, Hurricane Jimena is centered about 1075 miles southwest of Cabo San Lucas, Mexico, moving toward the west at 12 mph. Maximum sustained winds are near 90 mph, and Jimena could strengthen into a major hurricane over the next 24-48 hours. Jimena will remain over open waters, and is no threat to any land areas.

As Tropical Storm Erika continues to approach the Lesser Antilles, the questions remain the same as they were a few days ago: Where will Erika go and how strong will it get?

The first question is somewhat easier to answer in the storm term. As of 2pm EDT on Wednesday, Erika was centered about 245 miles east of Antigua, moving toward the west at 17 mph. It seems fairly likely that Erika will impact the islands of the northeastern Caribbean. As a result, Tropical Storm Warnings remain in effect from Puerto Rico and the Virgin Islands eastward to Montserrat, and a Tropical Storm Watch is in effect for Guadeloupe. A warning means that tropical storm conditions are likely within the next 36 hours, while a watch means that tropical storm conditions are possible within the next 48 hours.

How strong Erika will be when crossing the islands is still a big question. Currently, Erika has winds of 45 mph. The official forecast from the National Hurricane Center, is for Erika to maintain its current strength or strengthen slightly over the next 48 hours. However, there are some indications that it may actually weaken before then.

In the last few frames of the satellite picture, if you look closely, you can see the lower-level circulation of Erika pulling away from the western edge of the thunderstorm activity. This is a tell-tale sign that wind shear is still impacting the storm. For Erika to strengthen, the wind shear will need to lighten up, and allow the thunderstorm activity to redevelop near the center of the storm. Until that occurs, Erika will not gain strength. Some of the computer models are showing the possibility that Erika degenerates into a tropical wave as it nears or passes the Leeward Islands, similar to Tropical Storm Danny a few days ago. This would bring some much-needed rainfall to the drought-stricken region, without the sustained strong winds that normally accompany a tropical storm.

In the longer term, things become a bit murkier in terms of the track and strength of Erika. It seems fairly likely that what’s left of Erika will continue on a west to west-northwest track and could start to strengthen (or redevelop, if Erika dissipates), as it nears the Bahamas this weekend. At this point, there is no consensus as to what will happen.

The National Hurricane Center forecast (pictured above) brings the storm into South Florida as a weak hurricane early Monday. However, on the various forecast models, the solutions range from a track into the Eastern Gulf of Mexico to one the keeps it near or east of the Bahamas and then out to sea. There are some that show a potential threat to Florida or the Southeast, but since this is still at least 5-7 days away, the odds are fairly low at this point. Still, residents of the region should keep an eye on Erika, as it could have some impact early next week.

In addition to the track questions, there are plenty of questions as to how strong Erika will get. Erika should remain a weak tropical storm for the next 48-72 hours (unless it dissipates into a tropical wave). Beyond that, the uncertainty becomes large. Many of the forecast models keep it a tropical storm, while some strengthen it into a hurricane, in some cases a very powerful hurricane (see image below).  Assuming it survives the journey toward the Bahamas, conditions should be favorable for Erika to start to strengthen towards the end of the week. The track it ultimately takes will determine if it is able to get there.

If Erika does make landfall in Florida as a hurricane, it will be the first storm to do so since Hurricane Wilma did on October 24, 2005, nearly 10 years ago. In the hurricane database that goes back to 1851, the 10-year drought for Florida is the longest on record. The previous record was 6 years, between 1979 and 1985. While some may argue that the lack of landfalls is a good thing, in many ways, it’s also bad. Reports have indicated that over a million people have moved to Florida since 2005, and the vast majority of those people have likely never experienced a hurricane, let alone a major hurricane.  They may not know how to prepare for a storm that could leave them without power for a week or more. They may not know what a mandatory evacuation means or if they are in a mandatory evacuation zone. They may not know where the nearest shelter is located. Now would be a good time for residents of the region to brush up on this, in case Erika does threaten the region this weekend.

8-26-2015 2:41pm EDT