Before I get to the forecast, I wanted to give you a link to an update on the Gulf of Mexico Oil Spill. Of course we're all hoping and praying for the best, but it looks like a very serious ecological and economical disaster may be imminent for the Gulf Coast. Also, I continue to send my thoughts & prayers to the victims and their families of last week's oil rig fire. God bless everyone!
Oil Spill Update
Another Site for Oil Spill Information
The blog will be in severe weather mode through Sunday...
SW Louisiana Forecast Discussion...You can observe the much advertised changes just by gazing out the window this evening. This was right on track with what was laid out for you last night. It is windy, clouds and humidity have increased in earnest across the forecast area. This is all in response to a deep Southerly flow which is well established across the forecast area now as we lie in between weather systems. The controlling high of the last couple days is over the SE U.S., and a potent elongated Pacific trough resides out to our West. It is the squeeze play between the said systems that results in the tightening pressure gradient across the area. The windy conditions will prevail as the high over the SE acts as a blocking mechanism (something also discussed last week). The Pacific system over the Rockies and Great Plains will slowly move our way. Quiet weather is in store tonight with just the very humid air and windy conditions prevailing. Skies should range from Partly to Mostly Cloudy through the overnight hours. The air mass is soupy enough that an isolated streamer shower is certainly possible. However, without much of a trigger mechanism any rain would be luck of the draw tonight, so for this reason I will not officially mention it. Temperatures will be much above normal for Friday morning lows. After some very pleasant mornings in the 50s, lows tonight will be right around the 70 degree isotherm.
The mention of rain will certainly need to be mentioned on Friday. There really isn't much change in forecast philosophy from the previous forecast package. Let me elaborate...the much advertised potent Pacific storm will creep closer to the forecast area. The long fetch of deep Gulf moisture will continue. The associated cold front with the Pacific trough will slow and stall out somewhere to our NW. A strong Jet and SW flow aloft will allow for periodic perturbations to traverse the SW flow, and move NE across the forecast area out ahead of the stalling front. This should result in the development of scattered showers and thunderstorms across the area. However, there is a limiting factor that comes into play. The presence of an upper level cap exists tonight, and while this cap is beginning to weaken there is some question as to whether or not it will weaken enough by Friday afternoon to allow for storm development. Even if it does break, and storms fire this is still a set up that favors just scattered activity. It is not a given that everyone will get rain, but someone will...roughly about 30% of you. Now, the set up is one that does favor the possibility of some severe storms. The emanating short wave will engender shower activity over the coastal waters Friday, and these showers will move quickly to NE and intensify as they feed off of decent Jet Stream dynamics over land. The strong winds at the surface will also be veering with height and that suggests wind shear will be present. That means the possibility of some rotating storms which could produce isolated tornadoes. The short waves will generate cold pockets of air aloft as well, and this suggests the probabilities of some hail with any individual storm that develops. Winds increase with height as well, and every thunderstorm has updrafts and downdrafts. These downdrafts are strong surges of gusty winds that can often be translated down to the surface in a thunderstorm. This can lead to damaging wind in excess of 60 mph. All of these are possible with the scattered storms on Friday. Partly to Mostly Cloudy skies will prevail, and any sunshine we get will aid in storm development as that means we will reach our convective potential temperature easier. The current forecasted high is in the low to mid 80s. The severe weather threat will encompass a wide area Friday, expanding from over the Central Plains tonight. The severe weather threat area will extend from the Rio Grande Valley all the way to the Canadian border. The highest risk for severe weather will come right in the middle of this zone from the ARK-LA-TEX into the Mid West. A graphical representation follows (Severe Weather Outlook Day 2). You shouldn't let your guard down even though the severe weather possibilities will likely transpire further North. We aren't out of the woods here by any means. The best window of opportunity for severe weather to occur across the forecast area will be between 2p.m. and 8p.m. Friday. It will also remain very windy, with the pressure gradient force strengthening even a bit more. One thing I don't want to overlook as the likelihood that the persistent strong Southerly flow will lead to tidal backup on area rivers, and higher astronomical tides along the coast. The full moon factors into that equation as well. Astronomical tides are expected to be 1-2' above normal, and this could lead to see coastal flooding. For this reason, the National Weather Service has issued a Coastal Flood Watch for Jefferson County and Cameron, Vermilion, Iberia, and St. Mary Parishes. This is effect for Friday and Saturday. The strong, gusty winds will also create adverse conditions on inland waterways, and a Lake Wind Advisory is in effect for Friday. Rainfall totals could be in the 1-2" range wherever storms do occur, but the majority will see less than that. Rain chances will continue into Friday night with the front stalled out to our NW, and more disturbances likely to rotate through the established SW flow. The severe weather chances should be lessened mainly because of the loss of daytime heating. Activity will remain of the scattered variety.
Stay with me here, I know you want to know about the weekend forecast! There's a plethora of activities going on around our beautiful part of the world...Contraband Days, Fast Pitch 56, just to name a couple! These events will be able to roll, but could be impeded at times by shower or thunderstorm activity. Saturday appears to be the better weekend day as it stands right now. The same synoptic features will be in place as we start the weekend and the month of May. The stalled front will continue to be a player in the weather with a slight Southward progression possible during the day as the Eastern ridge shifts a bit. This will keep rain chances going across the area, and perhaps induce a slightly better coverage of activity. Intensity will be nearly the same, and the threat for severe storms may be realized once again. However, the best dynamics may shift a bit further NE to lessen the severe chances across the area when compared to Friday. All modes of severe weather will be possible once again, however, I would surmise that damaging wind and large hail will be the bigger threats. The set up will favor no organized convective, but it will be on a scattered basis once again. Also, the main time frame for convective activity will come in the afternoon hours. It will remain windy and very humid with high temperatures in the low to mid 80s after morning lows in the 70s once again.
Sunday will likely bring the highest chance of rain around these parts in a month. The stalled cold front will finally get an extra jolt from a dip in the Pacific trough, and it should surge through the area during the day Sunday. However, as it does so chances for showers & thunderstorms ramp up into the likely category. The synoptic set up will change a bit such that a line of showers & thunderstorms will likely develop, and with the copious amounts of low-level moisture in place multiple lines are possible. It is just waiting to be wrung out like a sponge. A severe weather possibility can't be ruled out, but at this time it appears that as the front comes through Sunday the set up will tend to favor a heavy rain event. Rainfall amounts could exceed 2" through the weekend, and the majority of that should come on Sunday since activity will be more widespread. Rain chances may ultimately end up maxing out, but for now placing chances in the likely category will suffice. The unseasonably warm low temperatures will continue with 70s for minimums once again while afternoon highs in the lower 80s. The highs will be a bit cooler because of more rainfall. The prolonged long deep Southerly flow will continue ahead of the boundary with gusty winds over 20 mph at times once again. Rain chances diminish Sunday Night as the front clears the area, and takes this nasty air mass with it. A refreshing breeze will take over, and some much nicer and drier air will be en route as well.
Improved weather is on tap beginning Monday in the wake of the early May cold front. Clouds will linger into Monday, but as high pressure builds in towards the Gulf coast during the day clouds will thin, and skies will become Mostly Sunny. It is the time of year now where it won't cool off much when we get a cold front, and that is the case here. Temperatures will really only drop to about seasonal for highs and lows. Some marvelous May weather will round out this forecast period Tuesday-Thursday with high pressure anchored over the Gulf. Temperatures will be fairly uniform each day with lows near seasonal values, but with increased subsidence and dry air in place afternoon highs will reach above normal levels into the upper 80s...almost hot! Summer isn't too far away now! A dry pattern looks to become re-established in the wake of our significant rain chances on Sunday, so if that is indeed the case let's hope we do get our much needed rain this weekend. The second weekend of Contraband Days looks dry and warm. Stay tuned!
Preliminary Numbers & Zone Forecast:
LCH 70/84 73/85 75/82 10 30 30 40 40 70
LFT 69/84 72/85 75/82 10 30 30 40 40 70
BPT 71/85 74/86 76/82 10 30 30 40 50 70
AEX 67/85 71/87 74/80 10 40 40 60 60 80
POE 67/85 71/86 75/80 10 40 40 50 60 80
ARA 71/83 74/84 76/81 10 30 30 40 40 70
*Lake Wind Advisory in effect Friday.*
*Coastal Flood Watch in effect for Friday & Saturday.*
Overnight...Mostly Cloudy & Windy. Low 70. SSE wind 15-20 mph and gusty.
Friday...Mostly Cloudy & Windy with a 30% chance of showers & thunderstorms. Some severe storms possible during the afternoon. High 84. SSE wind 20-25 mph and gusty.
Friday Night...Mostly Cloudy & Windy with a 30% chance of showers & thunderstorms. Low 73. SSE wind 20 mph and gusty.
Saturday...Mostly Cloudy & Windy with a 40% chance of showers & thunderstorms. Some severe storms possible during the afternoon. High 85. SSE wind 20-25 mph and gusty.
Saturday Night...Mostly Cloudy & Windy with a 40% chance of showers & thunderstorms. Low 75. SSE wind 20 mph and gusty.
Sunday...Cloudy & Windy with showers & thunderstorms likely. Heavy rainfall possible. 1-2" of rain expected. Isolated severe weather possible. High 82. SSE wind 20-25 mph and gusty, becoming SSW in the afternoon.
Friday 4/30/10 Daily Planner
6a.m.
Weather: Mostly Cloudy
Temp: 70
Precip: 10%
Wind: SSE 17
9a.m.
Weather: Partly Cloudy
Temp: 76
Precip: 20%
Wind: SSE 21
Noon
Weather: Mostly Cloudy, Windy
Temp: 80
Precip 30%
Wind: SSE 25
3p.m.
Weather: Scattered T-Storms, Windy
Temp: 84
Precip: 30%
Wind: SSE 25
6p.m.
Weather: Scattered T-Storms, Windy
Temp: 80
Precip: 30%
Wind: SSE 23
9p.m.
Weather: Mostly Cloudy
Temp: 77
Precip: 30%
Wind: SSE 21
Drew's 7 Day Outlook
Friday
4-30-10
Low: 70
High: 84
Rain: 30%
Wind: SSE 20-25
Saturday
5-1-10
Low: 73
High: 85
Rain: 40%
Wind: SSE 20-25
Sunday
5-2-10
Low: 75
High: 82
Rain: 70%
Wind: SSE/SSW 20-25
Monday
Low: 64
High: 81
Rain: 0%
Wind: NNW 10-15
Tuesday
5-4-10
Low: 61
High: 85
Rain: 0%
Wind: WNW 10
Wednesday
5-5-10
Low: 62
High: 85
Rain: 0%
Wind: W 5-10
Thursday
5-6-10
National Day of Prayer
Low: 64
High: 88
Rain: 0%
Wind: WSW 5-10
...Marine Forecast...
*Small Craft Advisory in effect until Sunday Morning.*
Tonight...Southeast winds 20 to 25 knots. Seas 5 to 6 feet. A slight chance of showers.
Friday...Southeast winds 20 to 25 knots. Seas 4 to 6 feet. A slight chance of showers and thunderstorms.
Friday Night...Southeast winds 15 to 20 knots. Seas 4 to 6 feet building to 5 to 6 feet after midnight. A slight chance of showers and thunderstorms.
Saturday...South winds 15 to 20 knots. Seas 5 to 6 feet. A slight chance of showers and thunderstorms.
Saturday Night...South winds 15 to 20 knots decreasing to 10 to 15 knots after midnight. Seas 4 to 6 feet. A chance of showers and thunderstorms.
Sunday...West winds 10 to 15 knots. Seas 4 to 6 feet. A chance of showers and thunderstorms.
Have a Great Friday & God Bless!
-DM-
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