SW Louisiana Forecast Discussion...September 2010 started off on a benign note across the forecast area. A typical late summer day or first day of meteorological autumn was experienced. Skies were generally Partly Cloudy with some Mostly Cloudy intervals. There was still plenty of moisture in place at the lower levels of the atmosphere, but some drier air worked into the mid and upper levels in response to a ridge off to our NE. A few afternoon storms developed, and were scattered at random across the landscape of the forecast area. Temperatures were very near seasonable values with readings starting out in the mid 70s, while afternoon highs reached the lower 90s. Afternoon heat indices topped out near 100. Mostly Clear skies with no mention of rain is on the slate for the overnight hours into Thursday morning. Expect Thursday morning minimums to range from the lower to middle 70s across the forecast area with a very light and subtle onshore flow in place. This weather pattern is much quieter than it was across the forecast area two years ago today. That's when Hurricane Gustav moved ashore in SE Louisiana near Houma and paralleled the Hwy. 90 corridor to near Lafayette. The storm sliced through the forecast area as it weakened. Most of SW Louisiana experienced at least tropical storm conditions.
The latter half of this work week will be rather benign as well. High pressure will continue to build in aloft, and at the surface. A mostly dry forecast will be maintained with generally Mostly Sunny to Partly Cloudy skies in place for Thursday. A few showers and storms will be scattered at random during the afternoon hours with the moisture in the low levels in place, and the favorable set up for another sea breeze type feature. Seasonable temperatures will be expected once again with highs in the lower 90s easily sustainable. The next synoptic feature comes into play on Friday. It is in the form of a deepening trough currently situated from the Red River Valley through the Mid West and up into the Great Lakes. This feature has a cold front associated with it. The upper level pattern across the country will favor a continued SE progression of said cold front, and there is enough upper level support to help pull this cold front through the entire forecast area. A few showers and storms will be possible out ahead of this boundary on Friday, but with the high pressure in place aloft the atmosphere will remain largely capped. A small chance of rain is indicated for this period for the reasons cited above. Temperatures on Friday will be nearly a carbon copy of Thursday with lows in the low to mid 70s and highs in the low to mid 90s. The cold front should push through the area during the day entering the Northern sections in the morning, and pushing offshore by Friday night. The atmosphere will dry out significantly beginning Friday night in the wake of the front. Go Bucs! Clear skies, a refreshing Northerly breeze, and somewhat cooler temperatures can be expected to lead us into Labor Day weekend. It won't feel too bad for the first Friday night of football this season considering its early September.
The forecast for the entire Labor Day weekend looks mighty nice. maybe verging on spectacular for early September standards in our part of the world. High pressure will build in in the wake of the front, and the atmosphere will continue to dry out at all levels. Humidity values will drop to below normal for early September, so no complaints there. Temperatures will be quite comfortable as well for the Saturday-Monday period. The drier and cooler air will be most noticeable first thing in the morning with morning lows dropping into the 60s for most locations. Readings as cool as the lower 60s will be possible by Sunday morning over the coolest locations across SW Louisiana. Here, in the immediate Lake Charles area expect minimums in the upper 60s on Saturday morning, mid 60s on Sunday morning, and upper 60s again on Monday morning. Afternoon highs each day will top out near 90, which is normal, and is still hot. However, with the dew points dropping into the 50s during the day, humidity values will be quite low and the heat index will be out of the equation. Hardly any clouds will be found for the entire Labor Day weekend. A little bit more moisture will hover near the coast which will closer to the frontal boundary, and that might conjure up an isolated storm or two on Saturday, but eventually the drier air will win out down there as well. Get out there and enjoy the holiday weekend. It will feel pleasant out at all of the football games as well. Go Cowboys & Tigers!
The end of the forecast period will offer up a transition back into a standard late summer pattern. Humidity values will increase again by Tuesday as a return flow is established across the area. The persistent Bermuda High will re-established itself over the SE United States early next week, and this will help the return flow kick in. This pattern will favor the development of an afternoon shower, and as such a chance for some scattered activity in the afternoon hours due to the effects of daytime heating. While the rain chances return to the forecast, the chances won't be any higher than average due to the continuation of drier air in the mid and upper levels. Temperatures will return to near normal for both highs and lows with morning lows reaching back into the low to mid 70s, while afternoon highs reach near the normal of lower 90s. The return of the humidity will make it feel more like late summer once again as heat indices near the century mark. This overall forecast pattern will continue to be dry with no significant opportunities for much needed rainfall anytime soon. Long range projections suggest an extended period of dry weather, this does not bode well for the ongoing drought conditions. We will continue to monitor the tropics this month as well. Earl is aimed at the East Coast this week, and is no threat to us. Fiona is no threat to land, and Gaston formed today. More on these systems in the tropical section below.
Preliminary Numbers & Zone Forecast:
LCH 75/93 76/94 69/91 10 20 10 20 0 0
LFT 75/92 76/94 68/92 10 20 10 20 0 0
BPT 76/93 76/95 70/92 10 20 10 20 0 0
AEX 73/95 73/96 66/91 10 20 10 20 0 0
POE 73/95 73/96 66/91 10 20 10 20 0 0
ARA 77/92 76/93 71/91 10 20 10 20 0 0
Tonight...Mostly Clear. Low 75. Light SSE wind.
Thursday...Partly Cloudy with a 20% chance of scattered afternoon showers & thunderstorms. High 93. SSE wind 10-15 mph.
Thursday Night...Mostly Clear. Low 76. Light SSE wind.
Friday...Partly Cloudy with a 20% chance of scattered afternoon showers & thunderstorms. High 94. SSE wind 10-15 mph.
Friday Night...Mostly Clear and Cooler. Low 69. NNW wind 10 mph.
Saturday...Mostly Sunny. High 91. NNW wind 10-15 mph.
Drew's 7 Day Outlook
Thursday
9-2-10
High: 93
Rain: 20%
Wind: SSE 10-15
H.I.: 98-103
U.V.: 11- Very High
Friday
9-3-10
High: 94
Rain: 20%
Wind: SSE 10-15
H.I.: 98-103
U.V.: 11- Very High
Saturday
9-4-10
Low: 69
High: 91
Rain: 0%
Wind: NNW 10-15
H.I.: 88-93
U.V.: 11- Very High
Sunday
9-4-10
Low: 66
High: 90
Rain: 0%
Wind: N 10
H.I.: 87-92
U.V.: 11- Very High
Monday
9-5-10
Labor Day
Low: 68
High: 92
Rain: 0%
Wind: NNE 10
H.I.: 90-95
U.V.: 11- Very High
Tuesday
9-7-10
Low: 71
High: 93
Rain: 20%
Wind: SSE 10-15
H.I.: 98-103
U.V.: 11- Very High
Wednesday
9-8-10
Low: 73
High: 94
Rain: 20%
Wind: SSE 10-15
H.I.: 100-105
U.V.: 11- Very High
...Tropical Update...
The tropics continue to heat up. The pattern favors what could turn out to be a September to remember in the tropics. Earl continues to be the main weather story as the calendar turns to September. Fiona is the least interesting of the tropical entities at this time, and should not be threat to land except for Bermuda as a weak storm in a few days. We have a new storm today as well with the emergence of Gaston in the Far Eastern Atlantic, and yet another wave is just emerging off the West Coast of Africa, and will certainly have a decent chance to develop over the next few days. The parade of storms typifies that it is indeed prime time hurricane season, and that all signs point to a very active Cape Verde season here in 2010. The slow start to the tropics is a fast, fading memory now as we've had the 4th storm in the last 11 days form in the Atlantic. Earl will continue to garner much of the attention for now, but by next week most of the focus will likely be on Gaston. Let's take a look at each system one by one.
East Coast Earl...Earl remains a very impressive looking hurricane on satellite imagery tonight. Earl has a very large, concentric eye. Earl has not began to feel the effects of wind shear over the Western Atlantic just yet. The environment over Earl is one that should allow the cyclone to maintain its current category 4 intensity tonight. There really isn't much change in the forecast philosophy from the previous forecast I laid out for you last night. Earl continues to be steered around the base of a large Atlantic anti-cyclone. A strong trough for early September will be approaching the Eastern U.S. over the next couple of days, and this will ultimately help dictate where the future track of Earl will be. Hurricane hunter aircraft have been flying through Earl tonight, and have found that Earl is strengthening as per a significant drop in barometric pressure would suggest. Earl is now at its peak intensity so far, and I suppose that the conditions are favorable enough to support some additional strengthening through the night. However, Earl is running out of time to mature much more, and it should be near its peak intensity at this juncture. Earl is currently a very dangerous category 4 storm. While the confidence in the overall track of Earl is high, it is still highly uncertain how much of the area from the Mid-Atlantic States to New England will be directly affected by Earl.
The aforementioned synoptic features will steer Earl, and Earl will begin to turn more Northerly sometime Thursday. It will be a very close call for the Outer Banks of North Carolina as far as a direct hit from the eye of Earl is concerned. Earl will begin to weaken as he moves further North as well given some wind shear developing out ahead of the approaching trough, and some cooler SSTs over North of the 30th parallel. Earl is forecast to begin the weakening trend, and will also accelerate its forward speed. Earl will likely still be major hurricane when its in the vicinity of the Outer Banks Thursday night. Again, it remains to be seen whether or not the Outer Banks Region will sustain a direct hit, but Earl will certainly be close enough to create some wind and rain over Coastal Carolina, and tropical storm force winds should certainly be realized. A large portion of the U.S. East Coast is under some sort of Hurricane or Tropical Storm Advisory given the uncertainty of the official track. Earl will continue accelerating to the N and NE beyond Thursday night as the trough magnifies over the Mid-Mississippi Valley into the Great Lakes. Earl will move parallel to the coastline, and give a glancing blow to Long Island and Cape Cod Friday into Friday night. It is also possible that these areas could sustain a direct hit from the eye of Earl, but it appears a bit less likely that far North. Certainly, still, tropical storm conditions could be realized well into New England and the Canadian Maritimes over the weekend. Earl will complete a transition to an extratropical cyclone over the weekend as he merges with the approaching trough somewhere in the vicinity of Hudson Bay. Everyone along the Eastern Seaboard from North Carolina into Canada needs to pay close attention and take the proper precautions. Evacuations are ongoing along the Outer Banks region of North Carolina. Earl will be out of the picture as we get into the Labor Day Holiday weekend, but many along the East Coast will likely spend it cleaning up from the storm.
Hurricane Earl Advisory
10p.m. CDT Wednesday, September 1, 2010
...Earl at its Strongest Intensity Yet...Poised to Threaten the Mid-Atlantic and New England Late Thursday through Late Friday...
Latitude: 27.8 N
Longitude: 73.8 W
This places the large eye of Hurricane Earl about 520 miles SSE of Cape Hatteras, NC.
Maximum Sustained Winds: 140 mph w/ higher gusts- category 4. Some fluctuations in intensity are possible overnight and on Thursday, but gradual weakening is expected to commence sometime on Thursday. Hurricane force winds extend outward to 90 miles from the center, while tropical storm force winds extend outward to 230 miles from the center.
Movement: NNW or 330 degrees @ 18 mph. This motion is expected to continue tonight with a turn towards the North expected on Thursday. On this track, the core of Hurricane Earl will pass very near or over the Outer Banks of North Carolina Thursday night. The eye of Earl should pass near or just offshore of the Delmarva Peninsula on Friday.
Minimum Central Pressure: 27.52" or 932 mb.
Watches/Warnings...A Hurricane Warning is in effect from Bogue Inlet, NC to the NC/VA border including Pamlico and Ambermarle Sound.
A Hurricane Watch is in effect from the NC/VA border to Cape Henlopen, DE and from Woods Hole, MA to Sagamore Beach, MA including Martha's Vineyard and Nantucket.
A Tropical Storm Warning is in effect from Cape Fear, NC to Bogue Inlet, NC and from the NC/VA border Northward to Sandy Hook, NJ including Delaware Bay South of Slaughter Beach and Chesapeake Bay South of New Point Comfort.
A Tropical Storm Watch is in effect from Sandy Hook, NJ to Woods Hole, MA including Block Island and Long Island Sound, and from Sagamore Beach to the Mouth of the Merrimack River, MA.
Interests in New England and SE Canada should continue to closely monitor the progress of Earl.
Wind...Tropical Storm force winds should reach the coast of North Carolina Thursday afternoon with hurricane force winds reaching that area Thursday night. Tropical storm force winds will likely spread up the coast from Virginia to New Jersey late Thursday through early Friday.
Storm Surge...Dangerous storm surge flooding will occur as water levels rise by as much as 3-5' within the hurricane warning area and Lower Chesapeake Bay. Elsewhere, water rises by as much as 1-3' will be possible in the tropical storm warning area.
Rainfall...Rainfall amounts of 2-4" with isolated amounts of over 6" will be possible over Eastern portions of North Carolina including the Outer Banks. Rainfall amounts of 1-2" are expected further North along the coast up into New England.
Surf...Large swells will continue to affect the Bahamas and the U.S. East Coast through Thursday. These swells will lead to dangerous rip currents and surf conditions.
Fiona...Feeble Fiona actually fought through the wind shear on Wednesday, and strengthened into a strong tropical storm. However, the environment out ahead of Fiona is not very conducive for continued strengthening at all. Little change in strength has occurred tonight after the burst of intensification on Wednesday. Strong upper level winds out ahead of Fiona are forecast by each of our global forecast models. The wind shear will be created by the steering pattern leftover in the wake of Earl. Fiona has been following very closely behind Earl, and as long as she does she will struggle to survive. Fiona close proximity to Earl, and the wind flow around the edge of the Atlantic ridge will lead to the highly sheared environment. I don't believe we will have to discuss Fiona much longer. Fiona is no threat to land save for Bermuda, but even still it will be a minimal storm at best, so the tiny island should receive no more than occasional squalls and some gusty winds. It appears that the center of Fiona (if there's anything left at that time) will pass just West of Bermuda over the weekend. Given the hostile environs that await Fiona, this tropical cyclone should disintegrate into an open tropical wave over the weekend.
Tropical Storm Fiona Advisory
10p.m. Wednesday, September 1, 2010
...Fiona Strengthens a Bit Temporarily...Degeneration Expected Over the Weekend...
Latitude: 21.8 N
Longitude: 64.1 W
This places the center of Fiona about 270 miles from San Juan, PR.
Maximum Sustained Winds: 60 mph w/ higher gusts. A gradual weakening trend is forecast through Friday. Tropical storm force winds currently extend outward to 140 miles from the center.
Movement: NW or 320 degrees @ 23 mph. This general motion is expected to continue with a decrease n forward speed expected through Friday. A turn to the North is expected Thursday.
Minimum Central Pressure: 29.53" or 1000 mb.
Now, there's Gaston...Gaston developed quickly from another wave that emerged off the West Coast of Africa. The formed Invest 98L is a long way out there in the Atlantic, and there is ample amount of time to watch this one. Gaston is further South than its predecessors, and it will be steered around the Southern flank of an Eastern Atlantic/Western Sahara High through between the Cape Verde Islands and the Leeward Islands through this forecast period. Models indicate steady state strengthening with Gaston, and this seems reasonable given the very conducive environment ahead of Gaston. Gaston will continue to strengthen, and likely become a hurricane sometime over the Labor Day weekend. It is conceivable that Gaston will become the season's third major hurricane down the road. The season's seventh named system will move nearly due Westward between 10-15 mph for the next few days.
Models indicate that Gaston may slow down as the steering currents weaken over the weekend. It is far too early to get a firm grip on where Gaston will be going, but there are certainly a couple of scenarios laid out by the models. Each one seems feasible at this time given the synoptic set up over the open waters of the Atlantic. Gaston could threaten the Lesser Antilles and the Caribbean next week, and then possibly continue further W or WNW and threaten the Gulf down the road. Gaston could feel a weakness in the ridge to its North, and begin to be pull Northward and eventually re-curve out to sea as it feels the influence of a trough next week. We should know a lot more about the future track of Gaston as he approaches the Caribbean next week. Earl is the main focus for now, but as Labor Day approaches, Gaston, will likely become the weather headline. This storm is a long way away from any portion of the continental United States. Don't worry about it at all this Labor Day weekend.
Tropical Storm Gaston Advisory
10p.m. CDT Wednesday, September 1, 2010
...Ghastly Gaston Growing in the Eastern Atlantic...
Latitude: 13.4 N
Longitude: 37.7 W
This is 935 miles W of the Cape Verde Islands and 1,585 miles E of the Lesser Antilles.
Maximum Sustained Winds: 40 mph w/ higher gusts. Strengthening is expected through Friday. Tropical storm force winds extend out to 70 miles mainly to the NW of the center.
Movement: W or 280 degrees @ 12 mph. This motion is expected to continue with a decrease in forward speed through Friday.
Minimum Central Pressure: 29.68" or 1005 mb.
Are you keeping up with me, here? A new tropical wave has emerged off the West Coast of Africa in the seemingly endless parade of tropical systems. The system is currently over the Cape Verde Islands at present. The system is not currently on the board with models just yet, but it should be within a day or two. Slow strengthening is expected through Friday, and this system sure seems poised to become our next tropical entity within a few days. The next name on the list is Hermine.
Elsewhere, no tropical cyclone formation is expected through Friday.
...Marine Forecast...
Tonight...East winds 10 to 15 knots. Seas 1 to 3 feet. A slight chance of showers and thunderstorms.
Thursday...East winds 10 to 15 knots. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.
Thursday Night...Southeast winds 5 to 10 knots. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.
Friday...East winds 5 to 10 knots. Seas 1 to 2 feet subsiding to 1 foot in the afternoon. A slight chance of showers and thunderstorms.
Friday Night...Southeast winds 5 to 10 knots becoming east after midnight. Seas 1 foot. A slight chance of showers and thunderstorms.
Saturday...Northeast winds 10 to 15 knots. Seas 1 to 2 feet.
Have a Great Thursday & God bless!
-DM-
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