SW Louisiana Forecast Discussion...It was a day much like we've had for the majority of this month...warm, breezy, & humid. Temperatures approached 80 degrees once again, but all this will be changing overnight as much cooler & drier air will take over thanks to a strong Pacific cold front. Morning lows were well above normal with readings in the upper 60s. An early morning low cloud deck gave way to Partly Cloudy skies by late morning. Areas of increased subsidence ahead of the front allowed for a good deal of sunshine this afternoon. The pressure differences ahead of the front continued with a strong onshore flow over 20 mph at times through the day.
The aforementioned front is currently beginning to push into the forecast area. Multiple lines of showers and embedded thunderstorms exist along and ahead of this frontal boundary, but the good news is there is very little in the way of severe weather ongoing at this time. No severe weather is occurring in the forecast area, and this will likely be the case for the duration of the event tonight. The atmosphere remains largely capped, and it is strictly the forcing associated with the front that is generating rainfall across the area. The capped atmosphere will likely preclude any severe weather threat across the forecast area, although there will be the possibility of an isolated severe cell or two mainly across the Northern and Western portions of the area where the cap is weaker. Better dynamics are in place further NE up into the Mid Mississippi Valley and parts of the Mid West, and the severe weather threat should be confined to this area. Some thunder and lightning will occur with the stronger storms across our forecast area along some gusty winds at times, but for the most part just general thunderstorms are expected. If the instability and dynamics were phased in together across the forecast area then we'd be talking about a significant severe weather outbreak. There is more than enough low-level moisture, but instability is marginal at best, and the dynamics are nearly non-existent across the area. The linear shower and thunderstorm activity will propagate Eastward overnight, and will weaken as they do so due to a stronger cap in place. The front will make steady progress and be pushing into the Lake Charles area by midnight, and into Acadiana by 2a.m. The chance of showers and thunderstorms will end shortly after frontal passage with just a brief window of post-frontal rain possible until drier air enters the mid and upper levels of the atmosphere. CAA will take over behind the front as well putting an end to the prolonged onshore flow with winds reversing to offshore at that time. This will begin to cool things down with temperatures falling into the mid 50s by sunrise Thursday. The threat for rain will end before dawn, and you need not bring your umbrella with you Thursday. Conditions will rapidly improve behind the front early Thursday, and we'll see skies clearing at that time. Rainfall totals will not be much at all, with generally 1/2" or less across the forecast area. It almost sounds crazy to say it, but we could stand to use some rain right now, if nothing else to wash away some of the persistent pollen problem. We should get off scott free once again as far as the severe weather aspect is concerned, so thank God for that.
The front will clear out all this 'gunk', and in its wake we'll see some chamber of commerce initiate on Thursday. High pressure will be in control in all levels of the atmosphere by Thursday afternoon. Any lingering clouds early Thursday morning will make like a magician and disappear by afternoon. Spring sunshine will be abundant, and temperatures will be more tolerable. Expect highs under modest CAA to be in the lower 70s. Refreshing offshore breezes will blow on the order of 15-20 mph at times Thursday before subsiding late in the day as the high pressure moves closer to SW Louisiana. CAA will cease by Thursday night as winds go near calm and with clear skies in place the stage will be set for maximum radiational cooling conditions. It will be the coolest night since the end of March. Overnight lows will drop into the low to mid 40s across the forecast area. This is trending below normal to start our Friday. It will feel chilly what with the prolonged stretch of unseasonable warmth so far this month. Super dry air will be in place with wall to wall sunshine, and we'll see a fast warm up into the mid 70s...just shy of early April norms! The great weather continues for this second weekend of April, however, a slow modification of temperatures will commence Saturday. The controlling high that will be right over head Friday will slowly push Eastward deep into the heart of Dixie, and this will bring back a weak onshore flow by Saturday. It will non-influential at first as the air will remain very dry with another day of Absolutely Awesome April weather expected. Morning lows will be a bit cool once again in the mid to upper 40s across the area, while afternoon highs should reach the very pleasant mid 70s once again. The latter half of the weekend will be almost as beautiful, but there could perhaps be a few clouds in the making for Sunday with a more established return flow in place by that time. The deeper low-level moisture will only slowly creep back into the area. Sunday morning temperatures should be in the lower 50s while Sunday afternoon temperatures should be a tad warmer in the mid to upper 70s...sounds like seasonable to me! Get out there and enjoy it!
The remainder of the forecast period (Monday-Wednesday) looks dry. High pressure will be in control in all levels of the atmosphere especially the mid and upper levels. The surface high will remained anchored over the Gulf South with slight day to day variations in its orientation. This is a pattern very similar to what has dominated the Southern U.S. for the last month or so. A very slow but steady modification of temperatures is in store during this time frame. Both highs and lows will be very close to seasonable for mid April for the Monday-Wednesday period. No mention of rain is forecast, and skies will generally be Mostly Sunny to Partly Cloudy at times. The presence of early morning low clouds and/or fog could possibly return by the end of the forecast period as more low-level moisture will be present at that time. The dry Spring of 2010 looks to continue with an overall dry pattern suggested by the long range models through mid April, but another rain chances will loom somewhere in the 8-12 day time frame. We'll just have to wait and see how all of this evolves.
Preliminary Numbers & Zone Forecast:
LCH 53/71 45/73 48/74 60 0 0 0 0 0
LFT 55/71 45/74 47/74 60 0 0 0 0 0
BPT 52/72 46/73 49/75 40 0 0 0 0 0
AEX 49/70 42/71 44/74 70 0 0 0 0 0
POE 49/70 43/71 45/75 70 0 0 0 0 0
ARA 57/72 47/74 49/75 70 0 0 0 0 0
Tonight...Cloudy with scattered showers & thunderstorms. Turning Cooler & Windy. Clearing late. Low 53. SSW wind 10-15 mph, becoming NNW 15-20 mph and gusty. Chance of rain 70%.
Thursday...Sunny, Breezy, & Cooler. High 71. NNW 10-15 mph.
Thursday Night...Clear & Cool. Low 45. Light North wind.
Friday...Sunny. High 73. NE wind 5-10 mph.
Friday Night...Clear. Low 48. Light East wind.
Saturday...Sunny. High 74. SE wind 5-10 mph.
Drew's 7 Day Outlook
Thursday
4-8-10
Low: 53
High: 71
Rain: 0%
Friday
4-9-10
Low: 45
High: 73
Rain: 0%
Wind: NE 5-10
Saturday
4-10-10
Low: 48
High: 74
Rain: 0%
Wind: SE 5-10
Sunday
4-11-10
Low: 52
High: 76
Rain: 0%
Wind: SE 5-10
Monday
4-12-10
Low: 54
High: 77
Wind: S 10
Tuesday
4-13-10
Low: 56
High: 78
Rain: 0%
Wind: S 10-15
Wednesday
4-14-10
Low: 60
High: 80
Rain: 0%
Wind: SSE 10-15
...Marine Forecast...
*Small Craft Advisory.*
Tonight...South winds 10 to 15 knots becoming northwest 20 knots after midnight. Seas 2 to 3 feet building to 3 to 6 feet after midnight. Scattered thunderstorms late in the evening. Scattered showers. Scattered thunderstorms after midnight.
Thursday...North winds 20 knots decreasing to 10 to 15 knots in the afternoon. Seas 3 to 5 feet subsiding to 2 to 4 feet in the afternoon.
Thursday Night...North winds 10 to 15 knots becoming northeast after midnight. Seas 2 to 4 feet building to 3 to 4 feet after midnight.
Friday...Northeast winds 10 to 15 knots becoming east 5 to 10 knots in the afternoon. Seas 1 to 3 feet.
Friday Night...Southeast winds 5 to 10 knots. Seas 1 to 3 feet.
Saturday...Southeast winds 10 to 15 knots. Seas 2 to 3 feet.
Good night and God bless!
-DM-
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