There is no video blog for this update, and this blog entry is in short form due to my impinging travel schedule. I will be away for the next few days, but I will post as I deem necessary over the coming weekend. I wanted to at least post something tonight to give you a heads up on the rain chances and Gulf storm that will develop late in the weekend into early next week. The regular format of the blog will resume next Tuesday, November 16. Thanks & sorry for the inconvenience.
SW Louisiana Forecast Discussion...As you have likely sensed the last couple of days, the muggies are back in full force across our part of the world. This is just a harbinger of things to come. You may recall in my post earlier this week I mentioned we would likely have rain chances in the offing for this second weekend of November, and that remains unchanged. As we head towards another weekend, we have experienced Partly to Mostly Cloudy skies with an occasional brief shower the last of couple of days thanks to the enhanced Gulf moisture. Patchy early morning fog and low clouds have been a staple as well since Tuesday. Most of the forecast area has remained rain-free on this Thursday with some showers noted in deeper moisture over East Texas. The lack of a trigger mechanism and a proverbial cap on the upper levels of the atmosphere has precluded most of the rainfall potential up to this point. It will still be a little while before this changes, but as the next system takes shape downstream we will head towards a weekend full of rain chances. I will get in depth into the ingredients coming together for this rain event in just a moment, but first you can expect the benign and stagnant weather pattern to persist in the short-term with generally Mostly Clear skies tonight along with some potential for patchy fog formation after midnight through first thing Friday morning. It will be on the mild side by November standards with low temperatures not unlike the past few nights with readings generally in the mid 50s to lower 60s across the region. The onshore flow will persist as well.
Friday should be another benign weather day with Mostly Sunny to Partly Cloudy skies across the area. There could be a renegade shower or two in the afternoon with the effects of daytime heating in the moist air mass, but overall the atmosphere will remain largely capped for one more day. The onshore flow will strengthen as our next weather maker gets its act together downstream. It is already present on satellite interpretations. A large autumn trough is digging Southward towards the Desert SW, and the active Jet Stream will force the attendant cold front towards the Gulf coast as we get into the weekend. Moisture will continue to pool over the area ahead of said trigger mechanism Friday, and this will lead to the introduction of rain chances by Friday night. The daylight hours of Friday should continue to be quiet as I said with the main focus for any rainfall remaining in the deeper moisture over East Texas once again. Afternoon high temperatures will trend above normal once again with the mercury topping out close to the 80 degree threshold. Then comes Friday night, which is very important for many of our area high schools. This is the first round of the 2010 State Playoffs. I don't anticipate any real weather problems for any of the games in our area. The slower evolution of this system should preclude most of the shower activity until later in the night Friday. It will be on the mild side with temperatures likely around 70 at kickoff and falling into the 60s for the remainder of the evening. Skies should generally by Partly to Mostly Cloudy, and an increase in cloud cover is likely over the area Friday night. Rain chances stand at 20% for mainly after midnight as the aforementioned cold front approaches.
The string of nice weekends will be broken it appears. There is a plethora of events including some big football games on the docket Saturday, so deriving an accurate forecast is essential here. While the concept of rain chances for the weekend remains unchanged, the extent of and the timing of said rain chances has changed a bit. This will certainly lead to some implications on your weekend plans, and for the football games which I will discuss thoroughly in a minute. The cold front will have no problem reaching our area, but models are incredibly consistent with the idea of a slowing down or stalling of this latest front during the day Saturday. It looks like it will push past the immediate forecast area, but will stall out in area that will cause repercussions on this forecast area. Rain chances will ramp up during the day Saturday in response to the front. Moisture in the lower levels will continue pooling over the area until frontal passage, and the front will not only add lift, but instability to the atmosphere thus allowing an erosion of the cap to occur. This will generate shower and thunderstorm activity across the forecast area Saturday. No severe weather is expected as the best dynamics will be steered away from the area by the active Jet Stream. This doesn't appear to be a significant or widespread rain event initially since the best lift and dynamics will bypass the area. Scattered convection appears to be the nature of this game this go around, but there could certainly be some heavier activity briefly as the front makes its pass through the area. The most likely time frame to see rain with this front will come between 6a.m. and noon Saturday. Winds will shift from offshore to onshore during the afternoon in the wake of the front.
A cooler air mass will be ushered in, but unfortunately not a drier one. We will see a brief drying in the wake of the front, but the clouds will hang tough. The front will stall out somewhere along a line from the Atchafalaya Basin to near Galveston Bay. The front will be detached from the mean flow across the contiguous states at this time, and will be bumping into a strong SW flow out ahead of it over the Gulf. This will lead to the front pulling up stationary. What happens next is something we are oh so familiar with around these parts as we get later and later into fall...the overrunning effect! The stalled front will cause the cool surface air to be overrun by a warm, moist flow aloft in the boundary layer. At the same time, the energy from the stalled front, and an additional upper level low rotating around the base of the digging trough will trigger cyclogenesis in the latter stages of the weekend. Weak isentropic lift (overrunning) will be in place Saturday afternoon and evening, and periods of mostly light rain or drizzle will occur during this time. Rain chances will be reduced during this period with the brief drying of the boundary layer, but I can't promise that the McNeese or LSU game will be entirely dry. It will certainly be overcast and cooler for the McNeese game with temperatures in the 60s at kickoff, and near 60 by game's end. The threat for rain during the LSU game will be a bit higher since they will be very near the stalled out front. It may very well be a wet Homecoming in Baton Rouge. The temperature forecast there is more of a crapshoot because pinpointing the exact location where the front will stall out is like trying to figure out which Tiger team will show up. It will be near 70 at kickoff and near 60 by game's end with the threat for showers and thunderstorms.
Rain chances will increase in earnest for Sunday and Monday as the isentropic lift strengthens. The stalled front will remain in nearly the same location. It may waver one way the other, but it seems as though this forecast area will remain in the cool sector. The Jet Stream energy and stalled front will ignite cyclogenesis, and the surface low will ride along the frontal boundary through the NW Gulf. This will throw moisture up and over the frontal boundary over our area. This will increase the threat for rain across the area, and it could be heavy at times. Thunderstorms are not out of the question, but with a cool, stable air mass in place at the surface these should be elevated in nature. Any threat for severe weather will remain to the SE of the stalled front, and to the right of the surface low over the Gulf waters. This set up is prime for a steady, soaking rainfall. This will help the ongoing drought that is plaguing SW Louisiana. Rainfall totals could be close an inch on Sunday. The timing of the surface low should put the worst of the weather over this forecast area Sunday night into Monday. It will be a slow evolution. Best rain chances and heaviest rainfall will be closer to the coast as is typical in this scenario. CAA will continue during this time as well, and temperatures will struggle to reach the 60 degree mark Sunday afternoon. So, it will be raw and dreary out there with a stiff NE wind adding misery. Rain chances continue in the likely category for Sunday night into Monday, and may very well max out for the Sunday night period as the low slides slowly Eastward. With the widespread rain expect temperatures to remain cool with a small diurnal range expected. Minimums heading into Monday morning will generally be in the upper 40s to lower 50s with the cool Pacific air mass locked in.
The overrunning rains continue Monday, but will slowly taper during the day as the surface low pulls away. It will also re-ignite the quasi-stationary boundary, and kick start it to the SE once again. A secondary front will also follow the surface low, so the cool air mass will remain in place. Rain will still have the potential to be heavy during the morning hours, but with boundary layer moisture decreasing in the afternoon, rain will begin to become more sporadic before ultimately ending Monday night. It will cool and raw with the rain continuing as well. Temperatures will struggle to the 60 degree mark once again. A stiff Northerly flow will be present as well to make it feel cooler. Total rainfall amounts from Saturday through Monday will range in the 2-4" range, and this looks to be a good soaker for our drought stricken region. It won't completely eliminate the drought by any means with a double digit deficit still in place across the area, but it will alleviate the severity of it. We are heading into our secondary wet season. The dreariness will be replaced with high pressure for the remainder of the forecast period. The rain ends Monday night, but the clouds may hang around into Tuesday before the sun makes an appearance once again. Strengthening CAA will result in a cool night Monday night into Tuesday with morning lows well down into the 40s. This air mass doesn't appear to be as cool as the one that we came out of last weekend, but it will still be below normal for mid-November nonetheless.
As mentioned a moment ago, high pressure replaces the low pressure for the rest of the forecast period. Some of the nicest weather all fall will be in store. High pressure nosing in from the Great Plains will provide a continuation of CAA, and lower humidity values will accompany that as well. Any lingering clouds go by the wayside Tuesday morning, and we'll see nothing but wall to wall sunshine through Thursday. CAA will continue, and temperatures will be about the same as well. The cool mornings will give way to pleasant afternoons. Temperatures will remain below normal through this period, and any talk of highs near 80 will just be an afterthought. CAA will cease after Thursday morning as winds go nearly calm with the high right overhead. The coolest period of the forecast period should come at that time when lows reach the lower 40s with some 30s in the coolest locations north of the interstate. A favorable pattern will be established after we kick this low outta here Monday for those who want an extended period of nice, dry, comfortable weather once again. This should continue into the following weekend as a zonal flow (W to E) becomes the dominant pattern across the Southern half of the U.S. Temperatures will warm up in that time frame, and moisture will begin to increase ahead of what models depict to be another slowly evolving storm early during Thanksgiving week.
Preliminary Numbers & Zone Forecast:
LCH 57/79 60/72 53/62 0 10 20 40 30 70
LFT 56/78 60/74 54/63 0 10 20 40 30 60
BPT 59/81 62/72 52/63 0 10 20 30 40 70
AEX 52/80 57/70 48/58 0 10 30 40 20 60
POE 52/80 58/70 48/59 0 10 30 40 20 60
ARA 58/77 61/75 55/65 0 10 20 40 30 60
Tonight...Mostly Clear. Low 57. Light East wind.
Friday...Mostly Sunny to Partly Cloudy. High 79. East wind 10 mph.
Friday Night...Partly to Mostly Cloudy with a 20% chance of showers and thunderstorms mainly after midnight. Low 60. SSE wind 10 mph.
Saturday...Mostly Cloudy with a 40% chance of showers and thunderstorms. Turning Cooler. Windy. High 72. SSW wind 15-20 mph and gusty becoming NNW in the afternoon.
Saturday Night...Mostly Cloudy with a 30% chance of rain. Cooler. Low 53. NNW wind 15-20 mph and gusty.
Sunday...Cloudy & Cool with rain likely. High 62. NNE 15-20 mph and gusty. Chance of rain 70%.
Friday 11/12/10 Daily Planner
6a.m.
Weather: Mostly Clear
Temp: 57
Rain: 0%
Wind: E 5
9a.m.
Weather: Mostly Sunny
Temp: 62
Rain: 0%
Wind: E 7
Noon
Weather: Partly Cloudy
Temp: 70
Rain: 10%
Wind: E 7
3p.m.
Weather: Partly Cloudy
Temp: 79
Rain: 10%
Wind: ESE 10
6p.m.
Weather: Partly Cloudy
Temp: 74
Rain: 10%
Wind: SE 5
9p.m.
Weather: Partly Cloudy
Temp: 68
Rain: 10%
Wind: SSE 10
Drew's 7 Day Outlook
Friday
11-12-10
Low: 57
High: 79
Rain: 10%
Wind: E 10
Saturday
11-13-10
Low: 60
High: 72
Rain: 40%
Wind: SSW/NNW 15-20
Sunday
11-14-10
Low: 53
High: 62
Rain: 70%
Wind: NNE 15-20
Monday
11-15-10
Low: 50
High: 60
Rain: 80%
Wind: NNE 15-20
Tuesday
11-16-10
Low: 45
High: 64
Rain: 0%
Wind: NNW 10-15
Wednesday
11-17-10
Low: 42
High: 68
Rain: 0%
Wind: N 10
Thursday
11-18-10
Low: 40
High: 70
Rain: 0%
Wind: N 5-10
...Marine Forecast...
Tonight...East winds 10 to 15 knots. Seas 2 to 3 feet.
Friday...Southeast winds 10 to 15 knots. Seas 2 to 3 feet.
Friday Night...Southeast winds 5 to 10 knots. Seas 2 feet. A slight chance of showers and thunderstorms.
Saturday...South winds 5 to 10 knots becoming west in the afternoon. Seas 1 to 2 feet. A chance of showers and thunderstorms.
Saturday Night...North winds 5 to 10 knots becoming northeast after midnight. Seas 1 to 2 feet. A slight chance of showers.
Sunday...Northeast winds 10 to 15 knots. Seas 1 to 2 feet. Showers likely and a slight chance of thunderstorms.
-DM-
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