SW Louisiana Forecast Discussion...The drier air has taken over, and now encompasses the entire forecast area. It will be nice to have a reprieve from the excessively hot and humid weather that has dominated the forecast all summer for a couple days. The temperatures being experienced during this breath of fresh air are certainly not earth-shattering by any means. In actuality, this weak cool front has only set us back to normal for late August. In this awful summer of 2010, normal is a good thing. The downside is that there is virtually no chance of any much needed rainfall from the typical daily dose of showers and thunderstorms we depend on this time of year. The high pressure in the wake of the feeble frontal zone has suppressed any vertical growth from any cumulus clouds that form during the heat of the day. Clouds were even a rare item on Wednesday with the drier air in place. Afternoon highs reached the low to mid 90s for most locations, but again this is normal in late August. The drier and somewhat cooler air will be more noticeable overnight and through sunrise Thursday morning. Temperatures will cool off at a faster than usual clip thanks to the lower dew points as initiated by the offshore flow. Many locations will dip below the 70 degree mark for the first time since May. While it's not much, it's a step in the right direction as we head towards September. The rest of us will easily see lower 70s with clear skies and nearly calm winds in place.
A similar weather regime is slated for Thursday with the dry, subsident flow in place. The early morning upper 60s and lower 70s will warm into the low to mid 90s by the afternoon hours, but the heat index will literally be non-existent thanks to the lower humidity. Cloud cover will be at a minimum, and there will be no chance of any rainfall yet again. While it will be nice by late August standards over land areas, there will be some action ongoing in the Gulf waters. The old frontal boundary remains nearly stationary over that area, and there is a persistent area of showers and storms as well. There are still some signs of weak cyclogenesis occurring within the next 24-48 hours as the frontal zone meanders about. An elongated trough will co-exist with the quasi-stationary boundary, and this will ultimately essentially cause the front to turn into a warm front. This transition will begin on Thursday, having virtually no effect on our weather in the short-term. An offshore flow will continue through Thursday night and into Friday morning, thus the pleasant late August weather will continue for a short while longer with upper 60s to around 70 for minimums under clear skies once again. Don't get used to the comfort!
The moisture will continue to pool in the offshore waters on Friday, but land areas will continue to remain dry. Initially, a subtle increase in low-level moisture will occur as the transitioning boundary lifts slowly Northward, and the weak surface low drifts Westward. This will keep all shower and thunderstorm activity confined to the coastal waters mainly to the South and East of the aforementioned synoptic scale features. Another pleasantly hot (if there is such a thing) afternoon is on tap for Friday with highs in the lower to middle 90s easily amassed. I suppose an isolated shower or storm or two could occur during the peak heating hours especially nearest the coast where the deeper moisture will be in closer proximity with the boundary lifting Northward, but this is a minuscule proposition, and is not worth noting in the official forecast at this time. The weather looks good for all the High School Football Jamborees across the area. It will be warm, but no threat of rain exists. Expect temperatures during this time frame to be in the 80s during the evening hours, before falling into the upper 60s to lower 70s across the scope of the forecast area heading into the final Saturday of August. This will be the last of the late August pleasantry.
The complex portion of the forecast lies within the weekend. The complexities come from the developments in the Gulf. The warm front like feature will continue lifting Northward through Saturday ushering in a return of the deep tropical air. This will bring back rain chances to the forecast across the area, with the best chances initially along and South of the I-10 corridor. It appears now that most of the widespread and heavier activity will remain suppressed over the coastal waters for one more day on Saturday as the weak surface low traverses the warm Gulf waters from East to West. It is certainly within the realm of possibility that this aforementioned low could garner some tropical characteristics, and try to develop further. Though, it seems unlikely to happen at this point, it is something we must watch closely for. This time of year it is always possible that a tropical system can form from an old frontal boundary if it sags into the Gulf waters, so this idea can't be ignored. Nevertheless, the weak surface reflection should evolve, and move slowly W or WSW towards SE Texas through Sunday. This will aid in moisture increase across the area, thus another reason to validate the return of rain chances. Showers and thunderstorms on Saturday will mostly be scattered in nature, and will be thermally induced for the most part. It should essentially be a normal late August day. The pleasant air of the early morning hours will quickly go by the wayside, and the humidity returns in earnest during the afternoon as maximums reach the lower 90s. Heat indices will be around 100, so it'll be back to feeling all nasty and junk. Rain chances increase further for Sunday, and this seems like the most likely day to receive rain over the course of this forecast period. The moist axis will be well established by this time with the weak surface low situated to the West of the area. This will keep a deep, moist, tropical air mass in place across the area, and the end result will be off and on rain and storms on Sunday. Rain chances will be in the likely category, and the area could stand to see 1-2" of rain at this time, but given the ongoing drought conditions in place a flooding problem is not expected. Further fine tuning is expected as we head into the weekend. The morning lows will be in the mid 70s, while afternoon highs remain just shy of the 90 degree mark. A stiff onshore flow is expected as well given the associated pressure differences associated with the Gulf low and re-building high pressure to our North.
The end of the forecast period Monday-Wednesday is more straightforward. Monday will still offer up a decent chance of showers and thunderstorms as the deep moisture influx hangs around for another day. The actual surface reflection should be over Central Texas. This will keep the Gulf wide open to send more rich tropical air in the lower levels over the area. The effects of daytime heating will also help conjure up an above normal crop of mainly afternoon showers and storms. The rainfall should not be as widespread or as heavy Monday due to the fact that a re-building ridge will be in transit over the area. This will begin to dry out the atmosphere in the mid and upper levels initially. More sunshine is on tap for Monday, and temperatures should respond accordingly. After highs at or just below the 90 degree mark on Sunday, temperatures will creep back into the lower to middle 90s by Monday. This will come after morning lows in the usual mid to upper 70s. All in all, it should be a fairly typical late August day. August comes to an end on Tuesday, and it will likely end on a dry and hotter than normal note. High pressure will build in at the surface as well by this time, and this will essentially shut off any chance of any natural air conditioning. An isolated storm or two is possible Tuesday, but if you get rain consider yourself mighty lucky. The chances of rain for Tuesday are too negligible to mention at this time. Expect lows in the mid 70s, and highs in the mid 90s with heat indices exceeding the 100 degree mark and likely at least approaching the danger category during peak heating hours. Wednesday is the start of September, if you can believe that! September should start with high pressure in control, with virtually no chance for showers and storms and above normal temperatures. It will be very resemblent of the summer of 2010 with lows in the mid to upper 70s and highs in the mid to upper 90s, and heat indices at or exceeding the 105 degree danger threshold. In the extended, dry and hotter than usual weather should prevail as we head into the all important Labor Day weekend.
Preliminary Numbers & Zone Forecast:
LCH 70/95 68/94 71/92 0 0 0 10 10 30
LFT 70/95 69/95 70/93 0 0 0 10 10 30
BPT 71/96 70/95 73/94 0 0 0 10 10 30
AEX 66/94 63/94 66/93 0 0 0 10 10 20
POE 66/94 63/94 67/93 0 0 0 10 10 20
ARA 72/95 70/95 73/91 0 0 0 10 10 40
Tonight...Mostly Clear and Refreshing for late August. Low 70. Calm wind.
Thursday...Mostly Sunny. High 95. NE wind 10 mph.
Thursday Night...Clear with Another Pleasant Night. Low 68. Light NE wind.
Friday...Mostly Sunny to Partly Cloudy. High 94. East wind 10 mph.
Friday Night...Clear. Low 71. Light SE wind.
Saturday...Partly Cloudy with a 30% chance of scattered afternoon showers and thunderstorms. High 92. SSE wind 10-15 mph.
Thursday 8/26/10 Daily Planner
6a.m.
Weather: Clear, Refreshing.
Temp: 70
Rain: 0%
Wind: Calm
9a.m.
Weather: Sunny
Temp: 82
Rain: 0%
Wind: NE 5
Noon
Weather: Mostly Sunny
Temp: 88
Rain: 0%
Wind: NE 8
H.I.: 91
3p.m.
Weather: Mostly Sunny
Temp: 95
Rain: 0%
Wind: NE 10
H.I.: 96
6p.m.
Weather: Mostly Sunny
Temp: 89
Rain: 0%
Wind: NE 5
H.I.: 92
9p.m.
Weather: Clear
Temp: 83
Rain: 0%
Wind: E 5
Drew's 7 Day Outlook
Thursday
8-26-10
18 Year Anniversary of Hurricane Andrew
High: 95
Rain: 0%
Wind: NE 10
H.I.: 93-98
U.V.: 11- Very High
Friday
8-27-10
Low: 68
High: 94
Rain: 0%
Wind: E 10
H.I.: 93-98
U.V.: 11- Very High
Saturday
8-28-10
Low: 71
High: 92
Rain: 30%
Wind: SSE 10-15
H.I.: 95-100
U.V.: 10- Very High
Sunday
8-29-10
5 Year Anniversary of Hurricane Katrina
Low: 75
High: 89
Rain: 70%
Wind: SSE 15-20
H.I.: 95-100
U.V.: 9- High
Monday
8-30-10
Low: 75
High: 91
Rain: 60%
Wind: SSE 15-20
H.I.: 95-100
U.V.: 9- High
Tuesday
8-31-10
Low: 75
High: 95
Rain: 10%
Wind: SSE 10-15
H.I.: 100-105
U.V.: 11- Very High
Wednesday
9-1-10
2 Year Anniversary of Hurricane Gustav
Low: 75
High: 96
Rain: 0%
Wind: SSE 10-15
H.I.: 100-105
U.V.: 11- Very High
...Tropics...
The tropics are quickly heating up. A week ago, you remember, I said it was eerily deceptive. We are certainly working our way through prime time hurricane season now right on schedule. We now have two named systems. Let's start with Danielle first.
Hurricane Danielle continues to churn and strengthen in the open waters of the Atlantic between the Lesser Antilles and the Cape Verde Islands. It has strengthened fairly quickly this evening considering the environment isn't a completely favorable one. There is still some shear in the general vicinity, but Danielle has been able to strengthen regardless as the shear begins to relax. Danielle looks a classic maturing hurricane on the satellite imagery tonight with a very symmetrical signature, and the first signs of a visible eye. Not only is Danielle's strength increase, it is also increasing in size. Danielle seems poised to become the season's first major hurricane by Friday. The official forecast reflects a continued strengthening from the current 100 mph winds, and Danielle is currently expected to be approaching major hurricane status sometime Friday or Friday night. The official forecast intensity of 110 mph may be a bit conservative considering the largely favorable environment in which Danielle will be moving over in the coming days. What little bit of shear that currently exists will cease within 24 hours.
Hurricane Danielle Advisory
10p.m. Wednesday, August 25, 2010
...Danielle Continues to Strengthen...Could Become Season's First Major Hurricane By Friday...
Latitude: 22.4 N
Longitude: 54.1 W
This places the eye of Hurricane Danielle about 650 miles East of the Northern Leeward Islands, and about 945 miles SE of Bermuda.
Maximum Sustained Winds: 100 mph w/ higher gusts- Category 2. Further strengthening is expected through Friday, and Danielle could be approaching major category 3 hurricane status by Friday. Hurricane force winds currently extend out 40 miles from the eye, while tropical storm force winds extend out to 175 miles from the eye.
Movement: NW or 320 degrees @ 17 mph. This general direction of motion is expected through Friday, while a reduction in forward speed is likely to occur.
Pressure: 28.79" or 975 mb.
Now onto the newly formed, Earl...The former Invest 96L that has been mentioned in preceding days has become better organized today, and been was officially classified as Tropical Depression 7 Wednesday morning. It continued to get better organized through the day, and has officially become the season's 5th named storm, Tropical Storm Earl. Earl has maintained itself tonight, and it hasn't changed all that much in appearance since its inception this afternoon. Earl is still most certainly a maturing storm, and has a very small structure at this time when compared to the larger Danielle. The atmospheric conditions ahead of Earl are conducive for development even though it is following closely on the heels of Danielle. The current forecast shows the anticipated further strengthening trend, however, it is possible that Earl may have a hard time getting his act together until Danielle moves further away. This is due to the environment left behind by Danielle, and the effects of possible lingering shear Danielle left behind. However, given the fact that Earl emerged a bit further South than Danielle, it could negate any shear and have no trouble in its maturation process.
All models indicate that Earl will become a hurricane by this weekend, and the current forecast laid out by the National Hurricane Center reflects this idea as well. Earl is being steered by the same subtropical ridge that has been controlling Danielle. The current nearly due Westward motion should continue for the next couple of days, before Earl veers to the WNW around the edge of the Subtropical Western Africa/Eastern Atlantic anti-cyclone. All of the models initialize this solution very well, and I see no reason to deviate from this philosophy. The future track of Earl beyond this period is a bit more cloudy. The most likely scenario that I see based on data that I have looked at suggests that Earl will become a fish storm as well, following very closely in Danielle's footsteps. Some models suggests that a ridge will build in to the North of Earl replacing the trough that will ultimately steer Danielle to the North. If this happens then the threat to the United States will be increased sometime around Labor Day. In the coming days, Earl could also pose a threat to some of the Lesser Antilles since it formed at a point further South than its predecessor. There is still a lot of time to watch Earl, and since it's in the formative stages often times models still have difficulty getting a good read on a particular system. Certainly though, Earl is poised to become the 3rd hurricane of 2010, and will likely grow in size as well. Here is the latest advisory on Earl so you can keep track at home, although you won't be able to plot him just yet on most hurricane tracking charts as he's way out there.
Tropical Storm Earl Advisory
10p.m. Wednesday, August 25, 2010
...Tropical Storm Earl forms & becomes the season's 5th named storm...Strengthening to a Hurricane by This Weekend is Expected...
Latitude: 14.7 N
Longitude: 33.6 W
This places the center of Tropical Storm Earl about 615 miles W of the Southernmost Cape Verde Islands.
Maximum Sustained Winds: 40 mph w/ higher gusts. Some strengthening is expected through Friday, and Earl could approach hurricane status by the weekend. Tropical storm force winds currently extend outward to 60 miles from the center.
Movement: W or 275 degrees @ 16 mph. This motion is expected to continue through Friday, and Earl will remain over the open waters of the Eastern Atlantic through the period.
Minimum Central Pressure: 29.71" or 1006 mb.
Elsewhere, in the tropics...A disorganized area of showers and thunderstorms along an old frontal boundary in continues to persist in the Central Gulf of Mexico. If any tropical development were to occur it would be a slow process. This weak area of disturbed weather will move slowly Westward over the next couple of days, and help to increase rain chances across the Northern Gulf coast this weekend. No additional tropical cyclone formation is expected through Friday.
...Marine Forecast...
Tonight...Northeast winds 10 to 15 knots increasing to 15 to 20 knots after midnight. Seas 1 to 2 feet.
Thursday...Northeast winds 15 to 20 knots decreasing to 10 to 15 knots in the afternoon. Seas 1 to 2 feet. A slight chance of showers and thunderstorms.
Thursday Night...Northeast winds 10 to 15 knots. Seas 1 to 2 feet. A chance of showers and thunderstorms.
Friday...Northeast winds 10 to 15 knots becoming east in the afternoon. Seas 1 to 2 feet.
Friday Night...East winds 10 to 15 knots. Seas 2 to 3 feet. A chance of showers and thunderstorms.
Saturday...Southeast winds 15 to 20 knots. Seas 2 to 3 feet building to 3 to 4 feet in the afternoon. Showers and thunderstorms likely.
...Tide Data...
Thursday Tides @ Calcasieu Pass
Low: 10:38a.m. 10:39p.m.
High: 4:35a.m. 4:22p.m.
...Toledo Bend Pool Level...
167.58'
...Lake Charles Climate Summary...
Wednesday, August 25, 2010
Low: 74
Normal Low: 73
Record Low: 59-1917
High: 94
Normal High: 91
Record High: 102-1924
Rainfall
Today: 0.00"
Month to Date: 2.52"
Normal Month to Date: 3.78"
Year to Date: 24.90"
Normal Year to Date: 37.02"
Record: 1.40"- 1974
Sensible Weather Observed Today:
None
One Year Ago (2009)
Low: 71
High: 91
Rain: 0.00"
5 Years Ago (2005)
Low: 77
High: 95
Rain: 0.00"
10 Years Ago (2000)
Low: 72
High: 96
Rain: 0.00"
Sunrise Thursday: 6:46a.m.
Sunset Thursday: 7:42p.m.
...Lunar Table...
Last Quarter- Wednesday September 1
New Moon- Wednesday September 8
First Quarter- Wednesday September 15
Full Moon- Thursday September 23
Have a Great Thursday & God Bless!
-DM-
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