SW Louisiana Forecast Discussion...Before I get to the discussion, here's an aside...The annual Perseid Meteor Shower is occurring this week. Tonight should be the peak of what is typically a great show. Peak viewing times will be between 2 and 5a.m., but you could spot a meteor really at any time over the course of the night. It is best to look off to the NE. It should be a great night for viewing as clear skies are expected. Now onto the discussion...A weak front in the vicinity helped usher in some drier air across much of the forecast area. Shower and thunderstorm was limited to Lower Acadiana and the offshore waters. Big thunderstorms developed along and out ahead of the boundary across SE and Central Texas...areas that desperately need the rain. The drier air across SW Louisiana helped to limit shower and thunderstorm activity unlike forecast models suggested. The original forecast for today suggested decent rain chances with said frontal boundary in close proximity, and the effects of daytime heating aiding in development of shower and thunderstorm activity.
High pressure is building in as the boundary washes out along the coastline. Shower and thunderstorm activity has been shunted into the offshore waters by this boundary. This will set the stage for drier weather for the next couple of days. High pressure at the surface will induce Northerly winds at the surface, and this will lower humidity values somewhat during the afternoon. The end result is drier air, therefore, rain chances will be limited for the end of the work week. Only an isolated storm or two is expected for both Thursday and Friday. Temperatures will be above normal as well for daytime maximum in response to the drier air. Average highs will be in the mid to upper 90s. Morning lows may actually be a few degrees cooler as well. The coolest locations in Northern portions of the forecast area should see lows right around 70, with mid 70s along I-10, and upper 70s still expected at the coast.
The dry pattern will continue into the weekend with no more than a 20% chance of an afternoon shower or thunderstorm as the continued Northerly surface flow inhibits sea breeze formation during the peak heating hours. One or two thermally induced thunderstorms certainly can't be ruled out. Expect temperatures to remain a category or two above normal with mid to upper 90s expected with a 100 degree reading or two possible towards Alexandria or Fort Polk. The drier air in place should allow for heat index values to remain below heat advisory criteria with readings up to 105 expected in the afternoon.
The drier pattern should continue early into next week, before a transition occurs. A shift in which high controls our weather is forecast to occur. The prevailing Desert High will slide back to the West where it belongs, and the dominant Bermuda High will build in from the East by Tuesday. This will bring back our typical mid-August weather pattern with an average chance of scattered shower and thunderstorm activity as sea breeze generation occurs with the return of the onshore flow. Deeper moisture will linger offshore through the weekend thanks to the offshore flow, but it will be poised to surge Northward across the area as soon as the onshore flow redevelops. The increase in moisture will decrease daytime highs back to normal levels to the low to mid 90s.
Nothing out of the ordinary is expected in the long-term with the ongoing battle between high pressure systems continuing for the second half of the month. The big weather story will be the tropics as we are heading into prime time now. More on the tropics below:
Tropical Weather Discussion:
The 2009 Hurricane Season is heating up as we head into mid-August now. Tropical Depression 2 formed on Tuesday, and is struggling to survive over the open Atlantic tonight. It is ingested a lot of dry air, and this has it fighting for survival tonight. Here's the latest advisory from the National Hurricane Center:
Tropical Depression 2- 10PM CDT 8/12/09
14.0 N
36.3 W
This is about 800 miles W of the Southernmost Cape Verde Islands.
Movement: West at 14 mph & this motion is forecast to continue for the next several days.
Maximum Sustained Winds: 35 mph- it appears that the depression is weakening tonight, but it still has some potential to intensify into a tropical storm over the next couple of days. If so, it's name would be Ana.
Pressure: 29.71" or 1006 mb.
Other notes of interest: The system was on the verge of becoming Ana this afternoon after a burst of convection fired up, but all of this has since diminished tonight, and the system is barely holding on. The low-level center is exposed to the East of whatever convection there is present. The dry air that is present, and marginal sea-surface temperatures will likely keep this system from developing much at all the next couple of days. It is possible that if convection does not redevelop Thursday, that advisories on the system may be terminated. As of now, this system is still forecast to become Ana within 24-48 hours, but only a slow intensification is expected, if any at all. Based on what has occurred tonight, I would say that the chances of termination or more likely than intensification. The official forecast track and satellite image is below. Some forecast models have also been included:
The next advisory on Tropical Depression 2 will be issued by the National Hurricane Center at 4 a.m. CDT, Thursday.
Elsewhere in the tropics, a vigorous tropical wave trailing behind TD 2 has emerged off the West Coast of Africa. This system has potential to develop over the next few days, and is forecasted by models to become a much more serious system than its predecessor. This one is located further South than TD 2 was at this location. It will pass South of the Cape Verde Islands on Thursday. It is moving to the West at 10-15 mph. It will be monitored for development in the coming days.
Stay tuned for more on the tropics in the coming days. Preliminary Numbers and Zone Forecast Follows:
LCH 74/95 73/97 72/96 0 10 0 10 0 20
LFT 75/95 73/96 73/96 0 10 0 10 0 20
AEX 70/97 70/98 71/98 0 10 0 10 0 10
BPT 74/96 74/98 73/97 0 10 0 10 0 20
ARA 76/95 74/96 74/96 0 10 0 10 0 20
POE 71/97 70/98 71/97 0 10 0 10 0 10
Tonight...Clear. Low 74. Light and Variable wind.
Thursday...Mostly Sunny. High 95. Light and Variable Wind.
Thursday Night...Clear. Low 73. Light wind.
Friday...Mostly Sunny and Hot. High 97. Light and Variable Wind.
Friday Night...Clear. Low 72. Light wind.
Saturday...Mostly Sunny with a 20% chance of an afternoon shower or thunderstorm. High 96. Light SE wind.
7 Day Outlook for Lake Charles & Vicinity
Thursday
8-13-09
74/95/10
Wind: Variable 5-10
H.I.: 100-105
U.V.: 11- Very High
Friday
8-14-09
73/97/10
Wind: Variable 5-10
H.I.: 100-105
U.V.: 11- Very High
Saturday
8-15-09
72/96/20
Wind: SE 5-10
H.I.: 100-105
U.V.: 11- Very High
Sunday
8-16-09
74/94/20
Wind: SE 5-10
H.I.: 100-105
U.V.: 11- Very High
Monday
8-17-09
74/94/20
Wind: SE 10-15
H.I.: 100-105
U.V.: 11- Very High
Tuesday
8-18-o9
74/94/30
Wind: SE 10-15
H.I.: 100-105
U.V.: 11- Very High
Wednesday
8-19-09
75/93/30
Wind: SE 10-15
H.I.: 100-105
U.V.: 11- Very High
Marine Forecast:
Tonight...Southwest winds around 5 knots becoming west after midnight.
Seas 1 foot. Isolated showers and thunderstorms.
Thursday...North winds around 5 knots becoming east in the afternoon.
Seas 1 foot. A slight chance of showers and thunderstorms.
Thursday Night...Southeast winds around 5 knots becoming east after midnight.
Seas 1 foot.
Friday...East winds around 5 knots becoming southeast in the afternoon.
Seas 1 foot. A slight chance of showers and thunderstorms.
Friday Night...Southeast winds around 5 knots. Seas 1 foot.
Saturday...South winds 5 to 10 knots. Seas 1 foot. A slight chance of showers and thunderstorms.
Tides Thursday:
Low: 5: 22a.m.
High: 4:02p.m.
Lake Charles Climate Summary for Wednesday, August, 12, 2009
Low: 78 Normal Low: 74 Record Low: 61-1967
High: 96 Normal High: 92 Record High: 102-1951
Rainfall Today: 0.00"
Month: 1.08" Normal Month to Date: 1.75"
Year: 34.79" Normal Year to Date: 34.99"
Sunrise Thursday: 6:39a.m.
Sunset Thursday: 7:56p.m.
-DM-
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