SW Louisiana Forecast Discussion...The end of August marks the end of meteorological summer, but of course, the official end to summer is still a few weeks away. However, here in SW Louisiana we could have typical summer weather into October, it just kind of varies from year to year. No telling what's in store for this year, but I can tell you that our typical summer pattern will carry over into the month of September. Today was very much a standard summer day with Partly Cloudy skies and some scattered afternoon and evening shower and thunderstorm activity. After a bout of early morning low clouds and patchy fog, the hot August sun came out and did its magic. Temperatures began in the mid 70s, and topped out in the lower 90s this afternoon. This cites another example of how close to normal it was. Heat indices were near the 100 degree mark with plenty of low level moisture in place. Shower and thunderstorm activity occurred, but to a lesser extent than the previous days because some drier air filtered into the mid and upper levels as a ridge to our NE begins to retrograde towards the forecast area. Any shower and storm activity from earlier today will completely fizzle out within an hour or two after sunset, and a state of quietide is in store for the overnight hours with just Partly Cloudy skies and lots of humidity. Overnight minimums as the page of the calendar turns to September will be in the middle 70s yet again. Here's a brief aside...On this date, August 31, 10 years ago back in 2000, the all-time record high temperature was set at Lake Charles. The mercury that incredibly hot Thursday afternoon soared to an amazing 107 degrees. This was during one of the worst heat waves to ever effect SW Louisiana.
The forecast for this entire period will be very similar. Drier air will continue to take over in the mid and upper levels, and some drier air will mix down into the lower levels as well as high pressure continues to backbuild into the forecast area. This persistent ridge will dominate the weather across the Gulf Coastal Plain. This will keep rain chances in the slight category through the entire Labor Day Holiday Weekend, and beyond. Generally Partly Cloudy skies are to be expected during the day with the chance for late night/early morning low clouds each day as well given the high amounts of low-level moisture. A few thermally driven storms will be possible during the peak heating hours as the persistent onshore flow at the surface will favor the development of the afternoon sea breeze. Rain chances will remain less than average through the period, and there will be slight day to day fluctuations through the forecast period. There will be very little in the way of synoptic scale features to produce anything significant in the way of rainfall. However, there will be a weak, late summer cool front sagging into the northern half of the forecast area. This feature could ultimately raise rain chances in the Friday-Saturday time frame, however, the mid and upper levels of the atmosphere will remain largely capped thanks to the controlling ridge. Still, one or two storms will fire during the afternoon hours. Overall, the Labor Day Holiday Weekend looks like a winner with seasonable temps, and minimal rain chances. All weekend activities including all the area football games will be fine, just a little hot with lots of humidity. Temperatures will be seasonal for early September with mid 70s for lows, and highs in the low to mid 90s each day. Heat indices will average right around 100, give or take a degree. Hurricane Earl will have no effect on our weather, but the building ridge and digging trough will ultimately steer Earl towards the Mid-Atlantic States in the latter half of the week as a formidable hurricane. It remains to be seen on the severity of the impacts to that region. More on that in the tropical section.
Preliminary Numbers & Zone Forecast:
LCH 76/93 75/93 76/93 10 20 10 20 10 10
LFT 75/92 76/93 75/93 10 20 10 20 10 10
BPT 76/92 76/93 76/94 10 20 10 20 10 10
AEX 73/94 73/95 74/95 10 20 10 20 10 10
POE 73/94 73/95 74/95 10 20 10 20 10 10
ARA 77/91 76/92 76/92 10 20 10 20 10 10
Wednesday...Partly Cloudy with a 20% chance of scattered afternoon showers and thunderstorms. High 93. SSE wind 10-15 mph.
Wednesday Night...Partly Cloudy. Low 75. Light SSE wind.
Thursday...Partly Cloudy with a 20% chance of scattered afternoon showers and thunderstorms. High 93. SSE wind 10 mph.
Thursday Night...Mostly Clear. Low 76. Light SSE wind.
Friday...Partly Cloudy. High 93. SSE wind 10 mph.
Drew's 7 Day Outlook
Wednesday
9-1-10
2 Year Anniversary of Hurricane Gustav
High: 93
Rain: 20%
Wind: SSE 10-15
H.I.: 98-103
U.V.: 11- Very High
Thursday
9-2-10
Low: 75
High: 93
Rain: 20%
Wind: SSE 10
H.I.: 98-103
U.V.: 11- Very High
Friday
9-3-10
Low: 76
High: 93
Rain: 10%
Wind: SSE 10
H.I.: 100-105
U.V.: 11- Very High
Saturday
9-4-10
Low: 75
High: 94
Rain: 10%
Wind: SSE 10
H.I.: 100-105
U.V.: 11- Very High
Sunday
9-5-10
Low: 76
High: 95
Rain: 20%
Wind: SSE 10-15
H.I.: 100-105
U.V.: 11- Very High
Monday
9-6-10
Labor Day
Low: 75
High: 95
Rain: 20%
Wind: SSE 10-15
H.I.: 100-105
U.V.: 11- Very High
Tuesday
9-7-10
Low: 76
High: 94
Rain: 20%
Wind: SSE 10
H.I.: 100-105
U.V.: 11- Very High
...Tropical Update...
Earl...Hurricane Earl is the big story tonight, and will continue to be through the weekend. Earl is a very powerful and dangerous category 4 hurricane tonight as it makes its closest approach to the Turks and Caicos Islands. The threat to the East Coast of the United States from the Mid-Atlantic to the New England states continues to increase. The jury is still out on exactly how adverse the weather conditions will get across that area, but it is possible that the eye of Earl could make 2 or 3 landfalls along the East coast from the Outer Banks of North Carolina to Long Island to Cape Cod and maybe even Coastal Maine. Future adjustments to the track are expected over the next few days. Earl will continue to move NW away from the Turks and Caicos Islands and brush by the SE Bahamas on Wednesday. The threat to the U.S. East Coast will come Thursday through Friday, and the storm will begin to move into the Canadian Maritimes over the weekend. Earl continues to be steered around the periphery of a large Eastern Atlantic subtropical ridge. An additional synoptic feature will come into play as we head into the latter half of the week. It is in the form of a deepening trough over the Great Lakes and Mid West. This trough and associated cold front will be approaching the East Coast of the United States as we head into the latter half of the work week. The flow out ahead of said trough will have a direct impact on the future track of Earl. Earl's intensity has leveled off for now, but it could strengthen a bit more over the next 24 hours before conditions become less favorable, at which time Earl should begin to weaken. Earl has remained at category 4 intensity, despite looking a bit less impressive tonight when compared to earlier today. The overall structure of the storm remains the same, but the eye is less visible. This is usually indicative of an eyewall replacement cycle. These are very common in the larger, more intense hurricanes.
Earl will remain a formidable hurricane, and while it is currently at a very potent category 4 state, some weakening will occur as Earl begins to move further North and start to parallel the Eastern Seaboard. The cooler SSTS to its North, and wind shear associated with the advancement of the early September trough will lead to a weakening trend beyond the next 24 hours. Earl will likely maintain itself at category 4 intensity through Wednesday, and then begin to weaken slowly by Thursday. Earl will begin to turn more to the NE as the influence of the trough increases. The current forecast intensity keeps Earl a major hurricane as it nears the Outer Banks of North Carolina on Thursday, and as a strong category 2 hurricane as it makes its closest approach to Long Island and Cape Cod in the Friday afternoon-Friday night time slot. The transition to a strong extratropical cyclone likely of hurricane intensity will begin beyond this point with Earl moving into the Canadian Province of Nova Scotia Saturday evening. Again, the actual track of Earl is still very uncertain, but it now appears that it will track close enough to the East Coast from the Mid-Atlantic to New England to spread gusty winds and squally weather over a large portion of the area. It seems increasingly likely that hurricane force winds may impact the coastline of North Carolina, and tropical storm conditions will make their presence felt further North in Coastal New England. A track further to the left (West) would increase the impacts greatly, and would increase the chances of hurricane conditions for many of the big cities along the East Coast. It is also possible that Earl could make that turn a bit sooner than currently forecast, and that would lessen the effects to the East Coast. It is pretty certain that Earl will be influenced by the incoming trough, but we shall wait and see as to how much of the United States is to be impacted by this season's second major hurricane. Earl has been moving swiftly throughout his journey, and as it is picked up by the advancing trough Earl's forward motion will increase. Evacuations will begin Wednesday morning for coastal sections of North Carolina. Many other areas will likely follow suite Wednesday and Thursday as Earl approaches. Hurricane Watches have already been issued for portions of the North Carolina Coast, and I fully expect additional Watches/Warnings to be posted on Wednesday.
Hurricane Earl Advisory
10p.m. CDT Tuesday, August 31, 2010
...Earl Maintains Category 4 Strength...Impacts to East Coast of U.S. Likely Thursday and Friday...
Latitude: 23.0 N
Longitude: 69.9 W
This is about 130 miles NE of Grand Turk Island & 910 miles SE of Cape Hatteras, NC.
Maximum Sustained Winds: 135 mph w/ higher gusts- category 4. Very little change in strength is expected through Wednesday, and Earl should remain a major hurricane in the high end category 3 or low end category 4 range. The large wind field of Hurricane Earl is producing hurricane force winds outward to 90 miles from the eye, while tropical storm force winds extend outward to 200 miles from the eye.
Movement: NW or 315 degrees @ 15 mph. This general motion is forecast to continue on Wednesday, with a gradual turn towards the NNW expected thereafter. On this track, the core of Hurricane Earl will be passing well to the E and NE of the Turks and Caicos Islands tonight, and to the NE of the Bahamas on Wednesday.
Minimum Central Pressure: 27.76" or 940 mb.
Watches/Warnings....A Hurricane Watch is in effect for the Coast of North Carolina from Surf City Northward to the Virginia Border. This includes Pamlico and Ambermarle Sound.
A Tropical Storm Warning is in effect for the Turks and Caicos Islands, while a Tropical Storm Watch is in effect for the SE Bahamas, and for the Coast of North Carolina from Surf City Southward to Cape Fear.
A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued about 48 hours before the expected onslaught of tropical storm conditions. These conditions make outdoor preparations difficult.
Everyone from the Carolinas to New England needs to closely monitor the progress of Earl.
Wind...The Turks and Caicos are probably experiencing Tropical Storm conditions as of this writing. Conditions will improve over this area Wednesday as Earl moves further away.
Storm surge...Above normal tides accompanied by large, dangerous and battering waves are possible in the Turks and Caicos Islands and the SE Bahamas tonight.
Rainfall...Rainfall totals of 1-3" with isolated higher amounts to 6" are expected in the SE Bahamas and over the Turks & Caicos Islands through Wednesday.
The next intermediate advisory from the National Hurricane Center will come around 1a.m. CDT Wednesday, with the next complete advisory to follow at 4a.m. CDT Wednesday.
Fiona...Tropical Storm Fiona has been struggling to survive. It maintains its tropical storm intensity, but barely. Fiona is following very closely on the heels of Earl. This is having a significant impact on the circulation. While, most of the conditions in place are favorable for the fickle Fiona to strengthen further, this process has been negated by significant wind shear out ahead of Fiona. This wind shear is being created by the circulation around Earl, and the current left behind by Earl. In fact, Fiona has been eaten up so much by the wind shear in its vicinity, that it doesn't even take on the shape of a classic tropical system anymore. However, the center of circulation remains clearly evident tonight. There is some deep convection near the center, so keeping this classified as a tropical system is justifiable for the time being. The intensity of Fiona is 40 mph, a minimal tropical storm. Fiona will continue to struggle to survive for the next several days.
The ongoing wind shear could lead to the demise of Fiona especially given the fact that the shear is forecast to increase in the days ahead as the circulation of enormous Earl wraps into the flow of Fiona. Fiona will ingest the increasing shear, and will likely not get much stronger at all. In fact, dissipation seems more likely than anything at this juncture. There is a small window of opportunity for Fiona to marginally strengthen through Wednesday, but this window will close rather quickly as the cyclone moves into the highly sheared environment. Fiona is expected to remain a weak storm, and is forecast to dissipate over the open waters of the Atlantic in about 4-5 days. This can certainly change especially if Fiona can get further removed from the circulation around the back side of Earl. Fiona is following so closely on the heels of Earl, that it will be affecting the Northern Leeward Islands Wednesday, thankfully, with minimal effects when compared to her predecessor on Monday. Fiona is currently being steered around the southern edge of the same anti-cyclone which has been controlling Earl. However, as Fiona moves further West, it will begin to take on a more NW to NNW heading. This is as the result of a Southerly flow that has developed in the wake of Earl, and the building Bermuda High. Fiona poses no threat to land, and dissipation is forecast as we head into Labor Day weekend.
Tropical Storm Fiona Advisory
10p.m. CDT Tuesday, August 31, 2010
...Fickle Fiona Following Closely Behind Earl...Remains a Minimal Tropical Storm...
Latitude: 16.9 N
Longitude: 59.4 W
This is about 260 miles ESE of the Northern Leeward Islands.
Maximum Sustained Wind: 40 mph w/ higher gusts. Very little change in strength is expected through Wednesday, with weakening forecast to occur beyond that point. Tropical storm force winds extend outward to 140 miles from the center of circulation.
Movement: WNW or 290 degrees @ 20 mph. A turn to the NW is expected to occur on Wednesday. On the forecast track, Fiona is expected to pass near or just NE of the Northward Leeward Islands on Wednesday.
Minimum Central Pressure...29.71" or 1006 mb.
Watches/Warnings...A Tropical Storm Warning is effect for the islands of St. Martin & St. Barthelemy . A Tropical Storm Watch is in effect for the following islands: Antigua, Barbuda, Montserrat, St. Kitts, Nevis, Anguilla, St. Maarten, Saba, & St. Eustasius.
Wind...Tropical storm conditions may overspread the Northern Leeward Islands on Wednesday.
The next intermediate advisory on Fiona will be issued at 1a.m. CDT Wednesday, while the next complete advisory will follow that at 4a.m. CDT Wednesday.
Elsewhere, we continue to watch another Cape Verde tropical wave that has the potential to develop down the road. The environment over the Far Eastern Atlantic is conducive for environment, so it seems likely that this system will come Gaston in the days ahead. It is still an organizing system, and it's far too early to speculate on whether or not this would pose a threat to any landmasses. Of all the cyclones that have emerged off of Africa so far, this one is further South, and will have a better chance of threatening the Gulf of Mexico down the road. However, there is no way to tell for sure. The storm is on board as Invest 98L, and models have initialized the system as well. It is not a classified system as of yet, and that's why it is hard to discern any significant pattern. There is a low chance of development with this system for the next 24 hours.
No other tropical entities are expected to develop through Wednesday.
...Marine Forecast...
Tonight...East winds 10 to 15 knots. Seas 2 feet. A slight chance of showers and thunderstorms.
Wednesday...East winds 10 to 15 knots. Seas 2 to 3 feet. A chance of showers and thunderstorms.
Wednesday Night And Thursday...Southeast winds 10 to 15 knots. Seas 2 to 3 feet. A slight chance of showers and thunderstorms.
Thursday Night...Southeast winds 10 to 15 knots decreasing to 5 to 10 knots after midnight. Seas 2 to 3 feet.
Friday...East winds around 5 knots becoming southeast in the afternoon. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.
Have a great Wednesday & God Bless!
-DM-
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