SW Louisiana Forecast Discussion...Good morning. Can you believe it's the last day of June, and the last day of the first half of the year? 2010 is flying by. This week is flying by, yet it has seemed so long already with the extensive coverage of newly upgraded Hurricane Alex in the Gulf. Alex has been and will continue to be the weather story for the next couple of days. He will have an impact on our weather here in SW Louisiana, but we will certainly dodge the bullet escaping the brunt of the storm. The specifics of what kind of weather we can expect and when are to be highlighted in this blog. For the most up to date information on Hurricane Alex see the preceding blog.
The rich tropical air mass associated with Alex is in place, and a large rain shield associated with Hurricane Alex is creeping towards the coast early this Wednesday morning. This will change the weather across the forecast area today when compared to the first half of the work week. Activity has been strictly on a scattered basis thus far this week, but with Alex advancing towards the Rio Grande Valley of South Texas and Northeast Mexico the stage is set for numerous to widespread showers and thunderstorms today. Rain will be off and on throughout the day today, and it will be in the likely category for the entire forecast area. Although, in this situation the rain chances will certainly be highest at the coast, and lowest at the far inland areas of the forecast area. Rain chances at the coast will nearly be maxed out, while they will be tapered downward to near 60% across the extreme north. Considering this, we take the average to create a rainfall chance for the day. This stands at a healthy 80%, and the occasional squalls will produce periods of heavy rain. Some localized flooding can't be ruled out, thus the National Weather Service in Lake Charles has issued a Flash Flood Watch for the Southern half of the forecast area. This includes all parishes and counties along and South of I-10. Rainfall totals could exceed 2" today in some areas, but will average 1-2" area wide. Mostly Cloudy skies are expected with the advancement of the large cloud mass associated with Alex moving over the area. This cloud cover along with the high likelihood of rainfall will keep temperatures down several categories from what has been experienced lately. In fact, high temperatures will be hard pressed to even reach normal values. A maximum in the upper 80s shall suffice. In this situation, rainfall is not limited to the afternoon hours, but this is the time when the chance of getting wet will certainly be at its highest point due to the added effects of daytime heating in the rich, tropical air mass. This rich, tropical air mass is conducive for rainfall to occur at any point during the day, and pinpointing exactly when it may rain at your location is near impossible. It just depends on the movement of the outer rain bands. Alex will be making landfall sometime tonight most likely in South Texas or Northeast Mexico, and the slug of moisture on its East side will continue to be pumped into our area. Therefore, rain chances will remain in the likely category for tonight as well. The only other effect from Alex on our area worth mentioning is an increase in surface winds. A long fetch SE flow will develop around the circulation from Alex, and winds will be on the order of 20-30 mph at times especially in squalls. Also adding to the complexity of the forecast is a weakening and stalled frontal boundary to our North. This is the same front that I first mentioned last week, that some models had suggested would push through and give us a breath of fresh air for the 4th of July, but because of Alex this front will not make it through. It will undergo frontlysis (dissipation) to our North. However, with the boundary still in the vicinity, other areas of showers and thunderstorms are expected to occur. Throw that into the equation and it certainly spells a wet end to the month of June.
Alex moves inland and begins to decay Thursday, but the rains from Alex will continue thanks to the large slug of moisture over the Gulf. Therefore, rain chances remain very high for Thursday, although they should be a bit less than that of today. Another 1-2" of rainfall on average is expected Thursday, but again some areas could see as much as 4". It all hinges on the final movement of Alex, and the progression of his outer rain bands. Either way, our weather is certainly going to be much better than it will be for the folks in South Texas. The rainfall will be beneficial for our area as we remain in moderate drought conditions. The Flash Flood Watch and Coastal Flood Watch is in effect through Thursday morning based on the current forecast from the NHC on the official track of Alex. The continued high likelihood of rain, and generally Mostly Cloudy skies will keep temperatures down somewhat into the upper 80s once again. For the same period, morning lows will be very warm as well in this soupy atmosphere. The minimums will struggle to fall below the 80 degree threshold. Upper 70s seems reasonable in this atmosphere. The winds will begin to decrease somewhat as the storm spins down inland over Mexico or West Texas. Slow improvement is likely the best way to describe the progression of this forecast. Rain chances will continue on the high side for the Thursday night period as well, but slowly decrease in response to the decaying Alex. The decaying boundary will not as much of a factor across the area on Thursday, but could still conjure up additional storm development across parts of the forecast area.
Friday-4th of July weekend...Friday starts the improvement of our weather just in time for the holiday weekend. Deep tropical moisture will still be in place, and will be slow to leave with no boundary to come through and shear it out. As such, the decaying Alex combined with daytime heating will again produce rain chances in the likely category. However, the rainfall should not be near as widespread as it will be for the next couple of days as we start to transition back to the typical summer pattern. High temperatures will respond as well with more in the way of sunshine expected. Expect maximums to reach to near 90 or just above. By the weekend itself, Alex will be fast, fading memory, and we will be working our way back to a normal summer regime. The deep tropical moisture will be very slow to leave, and without any boundary to push it out of here coming down anytime soon, we will be hard pressed to get rid of it entirely. Thus, a continued chance of scattered showers and storms is expected for both Saturday and Sunday. As we try to complete the transition from a tropical system to a typical summer style regime, rain chances will decrease incremently each day. Saturday will be more likely to see rain as opposed to Sunday, the 4th itself. Saturday's coverage stands at about 40% while values near climatology are expected for Sunday at 30%. Temperatures will also respond with plenty more sunshine especially in the morning before the sea breeze and all the usual malarky that goes on. Expect highs to range from the low to mid 90s area wide, while morning lows will range in the mid to upper 70s. This forecast is not really much different at all compared to last night's forecast package. Of course, there is a plethora of events activities this weekend as we celebrate our Independence. While there will be chances for showers and thunderstorms, I certainly wouldn't cancel any 4th of July plans you may have. Just be aware that you may have to slightly alter them for a bit should a scattered storm move in your general direction.
Monday-Tuesday...The end of the forecast period, and the extra weekend day for most should be fairly uneventful. The new week should start on a much quieter note than this week did. Both Monday and Tuesday offer continued opportunities for scattered afternoon sea breeze shower and thunderstorm activity, but nothing out of the ordinary for July. July is the wettest month of the year in SW Louisiana, and we shall see if July 2010 will live up to that moniker. The controlling upper level ridge that has dominated the weather for the most part around here this summer should remain further out West where it belongs, to allow us to feel more of an influence from the persistent Bermuda high in the Western Atlantic and over the SE U.S. This will keep us in a favorable synoptic set up for the scattered afternoon storms Monday and Tuesday. You know how it is, there's no way to pinpoint exactly who will receive a nice cooling present from Mother Nature, and who will be left to burn to a crisp in the hot July sun. It's all about being in the right place at the right time, but at least it's no tropical system. The temperature scheme for the end of the forecast period is one that we've seen all too often as well. Morning lows will remain in the mid to upper 70s, while the early July maximums will try to trend above normal once again with the average rain chances in place. Expect the maximums for the end of the forecast period to be in the low to mid 90s each day. Model data hints at more of the same weather beyond this forecast period barring any tropical turmoil which may churn up along the way. Models do hint at some tropical activity over the first couple weeks of July, but this is just speculation at this point, and we must look for and recognize any trends or definitive patterns before trying to pound out any specifics. We should also get rid of Alex before discussing that idea. In closing, here's one bit a climatology for you...Alex is first Atlantic tropical system in 15 years (1995) to become a hurricane in June.
Preliminary Numbers & Zone Forecast:
LCH 78/88 79/88 77/91 60 80 60 70 40 60
LFT 77/88 78/89 77/92 60 80 60 70 40 60
BPT 78/87 79/88 78/90 60 80 70 80 50 60
AEX 75/91 76/90 75/93 40 70 40 60 40 50
POE 75/90 76/91 75/93 40 70 40 60 40 50
ARA 79/87 78/88 78/90 70 80 60 70 40 60
*Flash Flood Watch in effect through Thursday morning.*
*Coastal Flood Advisory in effect until Thursday morning.*
Today...Cloudy with tropical rains likely. Rain heavy at times. 1-2" of rain possible. High 88. SSE wind 15-20 mph and gusty. Chance of rain 80%.
Tonight...Cloudy with off and on tropical rain likely. Rain heavy at times. An additional 1" of rain possible. Low 79. SSE wind 20-25 mph and gusty. Chance of rain 60%.
Thursday...Continued Cloudy with off and on tropical rain likely. Rain heavy at times. 1-2" of additional rainfall expected. High 88. SSE wind 15-25 mph and gusty. Chance of rain 70%.
Thursday Night...Cloudy with scattered tropical rain. Low 77. SSE wind 10-15 mph. Chance of rain 40%.
Friday...Partly to Mostly Cloudy with showers & thunderstorms likely. High 91. SSE wind 10-15 mph. Chance of rain 60%.
Drew's 7 Day Forecast
Wednesday
6-30-10
Low: 78
High: 88
Rain: 80%
Wind: SSE 15-20
H.I.: 92-97
7-1-10
Low: 79
High: 88
Rain: 70%
Wind: SSE 15-25
H.I.: 92-97
Friday
7-2-10
Low: 77
High: 91
Rain: 60%
Wind: SSE 10-15
H.I.: 95-100
Saturday
7-3-10
Low: 76
High: 92
Rain: 40%
Wind: SSE 10-15
H.I.: 98-103
Sunday
7-4-10
Low: 75
High: 93
Rain: 30%
Wind: SSE 10-15
H.I.: 100-105
Monday
7-5-10
Low: 76
High: 94
Rain: 30%
Wind: SSE 10-15
H.I.: 100-105
Tuesday
7-6-10
Low: 75
High: 95
Rain: 30%
Wind: SSE 10-15
H.I.: 100-105
...Tropical Update...
See the preceding post for the latest on the season's first hurricane, Alex. Alex will make landfall well to our SW along the coast of South Texas or NE Mexico later tonight or early Thursday. Elsewhere, in the tropics all is quiet for the time being.
...Marine Forecast...
*Small Craft Advisory in effect through Thursday evening.*
High seas and large swells will prevail over the coastal waters in response to the circulation around Hurricane Alex.
Today...East winds around 20 knots. Seas 4 to 6 feet. Showers and thunderstorms.
Tonight...East winds 10 to 15 knots. Seas 4 to 6 feet. Showers and thunderstorms likely.
Thursday...East winds 10 to 15 knots decreasing to 5 to 10 knots in the afternoon. Seas 5 feet. Showers and thunderstorms likely.
Thursday Night...East winds 5 to 10 knots. Seas subsiding to 3 feet. A chance of showers and thunderstorms.
Friday...North winds 10 to 15 knots. Seas 3 feet. A chance of showers and thunderstorms.
Good night and God bless! Have a great Wednesday, & until next time may even your cloudy days be filled with sunshine!
-DM-
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