SW Louisiana Forecast Discussion...At least it felt like winter today! The sun teased us for a few minutes this afternoon. One more day until we can see some much needed sunshine. It's been a week since we last saw it, so come Friday it will be a welcome site. However, first we have another El Nino system to get through on Thursday. High clouds blanketed the landscape today ahead of the next "float" in the never-ending parade. Unlike a typical parade though, these floats aren't throwing shiny objects and edible treats. In Mother Nature's parade it's more of the same ole cold and wet weather scenario that we've seen play out so many times this season. It was noticeably colder than the previous days as strong CAA controlled the weather over the area. A strong ridge of Arctic high pressure was settled over the Northern half of the U.S. We're on the Southern fringe of this, so we're experiencing below normal temperatures, but it's not as cold as it could be if the high was centered right over us. Temperatures across the region today struggled to reach the 50s, and with the wind it felt like the 40s all day long.
The Subtropical Jet Stream or "Pineapple Express" (not the goofy comedy) continues to take up residence across the forecast area. The cold front from Tuesday morning has stalled over the Gulf waters, and at the same time an embedded short wave in the flow across the Southern U.S. is moving towards the area tonight from the West. This short wave energy has helped to energize the Subtropical Jet Stream, and has led to cyclogenesis over the Western Gulf once again. This surface low has formed off the coast of South Texas, and will be trekking to the ENE paralleling the coast of the forecast area on Thursday. As the low moves closer, its associated warm pocket of air will lift up and over the cold air in place at the surface. As a result, a prolonged period of isentropic lift (overrunning) is expected through Thursday. The end result will be that nagging nuisance we are accustomed to in the winter months around these parts. Widespread light rain and drizzle will begin overnight, and spread NE across the forecast area on Thursday. Rain will mostly be light for the entire forecast area, but some moderate to occasionally heavy rain can't be ruled out especially closer to the coast in the areas which will in closest proximity to the advancing surface low. Rain chances will be highest near the coast, and much less across Central Louisiana. The surface low will remain offshore, and that is where the worst of the weather will occur, however, it looks like the low will track a bit closer to the coast than forecasted last night. Rain has developed downstream of the forecast area tonight as the low strengthens and begins to move NE over the coastal waters. A solid shield of light rain is inching its way up the Texas coast, and will begin across SW Louisiana before sunrise Thursday. Patchy drizzle is already ongoing across the forecast area. Rain will stand the chance to be at its heaviest between noon and 6p.m. on Thursday as the low makes its closest approach to SW Louisiana. The isentropic lift will continue through the day. The expected steady light rain shouldn't create another flooding issue, but if the rain is heavy some flooding problems will occur especially near the coast. The grounds remain very saturated across the entire area, but a persistent light rain or drizzle shouldn't exacerbate flooding problems. Forecasted rainfall totals should be less than 1" for most locations, but 1-2" is possible near the coast and over lower Acadiana. To add insult to injury, it won't be warm at all on Thursday as CAA continues across the area. After lows in the lower 40s tonight, highs on Thursday should remain in the 40s with upper 40s at best for the entire forecast area. Stiff NE winds over 15 mph at times will create wind chill readings in the 30s. Conditions in the offshore waters will be much worse than that over land. Mariners should expect treacherous conditions with high winds and seas as the low moves by.
Conditions improve drastically to round out the work week. The surface low will be over Dixie by Thursday night with rain coming to an end across the forecast area. A chance of light rain and drizzle will carry over into the evening hours, but as drier air filters into the region at all levels the rain will end, and skies will clear thanks to high pressure building in from the North. It will continue on the chilly side as temperatures head down into the 30s area wide for Friday morning. Wind chills will remain in play as well with strong Northerly winds in the wake of the low. Friday morning wind chill values should be in the 20s. Friday should provide a fantastic finish to a fast but dreary work week with the controlling high in place (finally some goodies from Mother Nature's parade). Seasonably cool temperatures in the mid 50s are expected for Friday afternoon under sunny skies.
Benign weather is expected for pre-Christmas weekend at least as far as rain goes. It was still be somewhat eventful with a strong cold front expected to push through on Saturday. After a chilly start with morning lows in the mid to upper 30s, afternoon highs will be similar to Friday, however, it will becoming increasingly windy during the day as the strong front pushes into the coastal waters. The front will come through dry, and it is the wind that will be the only sensible weather that occurs with it. A few clouds may be noted ahead of the boundary, but moisture will remain limited across the area as a large dome of high pressure controls the weather regime along the Gulf Coast for a change. A glancing blow of Arctic will infiltrate the region behind Saturday's front, and the stage will be set up for the second significant freeze of the season. Lows for the Saturday night/Sunday morning period should range from the mid 20s to lower 30s across the forecast area. The immediate coast may avoid freezing temperatures, but it's going to be cold wherever you are, nonetheless. Skies will remain clear, there will still be a bit of a Northerly breeze, and the atmosphere will dry out even further with a re-enforcing high taking effect. Frost should not be an issue on Sunday morning with the dew points extremely low. A satellite TV and a fireplace are required for Saturday night as the cold sets in. Find a good place to stay warm and watch the Saints game. Sunny skies prevail for church on Sunday, and for anything else as well. Granted, it will continue to be cold with highs in the low to mid 50s. Sunday night will bring about the risk for widespread frost as winds go near calm with a large high right overhead. Upper 20s could be experienced as far South as the I-10 corridor with mid 20s expected for the coldest locations. Even at the coast, temperatures will be right around 32. This will be similar to our freeze after the snow 2 weeks ago.
The much-needed quiet weather regime will carry over into the beginning of Christmas week 2009. The strong Arctic high will loosen its grip on SW Louisiana as it slides to the East. A modest modification trend will begin Monday afternoon. I should note here that the overall pattern for the remainder of 2009 is one that favors very cold temperatures in the coming days. The exact timing of the Arctic fronts that will usher in the unseasonably cold weather is TBD. However, there is much confidence that this will not be Monday. Monday will be another dry day with plenty of sunshine in place. Afternoon temperatures will be seasonable with mid to upper 50s expected. Beyond Monday, the forecast confidence declines...it is certain that the much colder pattern will be dominant for the second half of this month, but the confidence is lacking as to when the next Arctic front will arrive. Some models suggest Tuesday as was reflected in yesterday's forecast, however, some suggest the next sharp cold front to arrive late in the day on Wednesday. Arctic front often tend to be faster than indicated by models. Models are underestimating the strength of the cold air as judging by temperatures between -40 and -50 in parts of South Central Canada. This is the air mass that is poised to enter the contiguous 48 states next week, sending the Eastern 2/3 of the nation into the deep freeze. These Arctic air masses are typically very shallow, and the models don't handle shallow cold air very well at all. When does it reach the Gulf coast is the question? I have blended the forecast models for this package to account for my forecast philosophy that the Arctic air will arrive faster, and be stronger than indicated by models. That being said, I expect that the main thrust of this potential Arctic outbreak will still come just beyond this forecast period (maybe Christmas Eve or Christmas Day itself...give or take day). It's still a bit early to specifically elaborate on temperatures for Christmas, but needless to say any thoughts of a warm Christmas in 2009 should not come to fruition.
For Tuesday, brief moderation is expected as we await the arrival of the next surge of Arctic air. Clouds will increase, but it should remain dry for much of the day. It should be a seasonable day temperature wise with upper 30s to lower 40s during the morning while afternoon temperatures peak close to the 60 degree threshold. By Tuesday night into Wednesday morning, the cold front will be sweeping through the forecast area. Arctic fronts typically move faster than Pacific cold fronts. Moisture will pool ahead of the front, and bring our next decent shot of rain and perhaps a few thunderstorms as there appears to be a good deal of instability shown by the models in the Tuesday night-Wednesday time frame. I don't anticipate any severe weather at the moment, but we'll analyze this further as we get into the weekend and early next week when timing will become more confident. Wednesday's temperatures could be "confused". That is, another one of those days were temperatures fall during the day as opposed to rising like you would typically expect. This depends on the timing of the front. This will be reflected in the current forecast. A brief rise in temperatures during the morning, before readings plummet in the afternoon as the Arctic air begins to spew into the region. Rain should come to an end Wednesday afternoon as the cold Arctic air infiltrates the forecast area. The clouds will likely remain, however, as this is often a pattern that keeps cold air stratus in place for a while behind a front. This occurs especially with these shallow air masses, when temperature inversions are present in the upper levels. Christmas Eve and Christmas Day are just beyond the forecast period tonight, but we'll get our first official crack at a forecast for Christmas Eve tomorrow and for Christmas Day on Friday. I expect another surge of Arctic air to arrive during the day Christmas Eve with temperatures getting progressively colder into Christmas Day itself. Hard freezes seem likely for the entire Gulf Coast for Christmas and Christmas weekend. Surges of Arctic air look to continue moving Southward to the Gulf Coast through New Year's, and if this pattern sets up just right we could see the coldest temperatures we've seen in years at some point before the end of the year. The active southern stream of the Jet Stream could rear its ugly head down the road as well. The cold air coming down next week will likely lead to a winter storm somewhere in the South, which could create headaches for Christmas traveling. The bottom line is that the 70 degree weather we had on Monday was likely an anomaly for December 2009, and all signals point to cold, cold, cold, and more cold to close out 2009. Stay tuned!
Preliminary Numbers & Zone Forecast:
LCH 42/48 40/55 38/53 40 80 30 0 0 0
LFT 43/48 40/56 39/52 30 80 30 0 0 0
BPT 44/48 41/56 40/54 60 80 20 0 0 0
AEX 38/45 37/53 35/48 20 40 20 0 0 0
POE 39/45 37/54 36/49 20 40 20 0 0 0
ARA 44/48 40/56 39/53 30 90 30 0 0 0
Tonight...Cloudy with a40% chance of rain after midnight. Low 42. NE wind 10-15 mph. Wind chill 30-35 by sunrise.
Thursday...Cloudy with light rain and drizzle likely. Some heavier rain at times. Up to 1" of rain expected. Cold. High 48. NNE wind 15-20 mph and gusty. Wind chill 35-40. Chance of rain 80%.
Thursday Night...Cloudy with a 30% chance of light rain or drizzle early, then Clearing overnight. Low 40. NNW wind 10-15 mph.
Friday...Sunny. High 55. North wind 10 mph.
Friday Night...Clear. Low 39. Light North wind.
Saturday...Mostly Sunny, Turning Cooler and Windy. High 53. NNW wind 15-20 mph and gusty.
Drew's 7 Day Outlook for Lake Charles & Vicinity
Thursday
12-17-09
Low: 42
High: 48
Rain: 80%
Wind: NNE 15-20
W.C.: 30-40
Friday
12-18-09
Low: 40
High: 55
Rain: 0%
Wind: N 10
Saturday
12-19-09
Low: 39
High: 53
Rain: 0%
Wind: NNW 15-20
W.C.: 40s
Sunday
12-20-09
Low: 31
High: 54
Rain: 0%
Wind: N 10-15
Monday
12-21-09
Winter Solstice
Low: 30
High: 57
Rain: 0%
Wind: NE 5-10
Tuesday
12-22-09
Low: 37
High: 61
Rain: 0%
Wind: SE 10-15
Wednesday
12-23-09
Low: 44
High: 56
Falling to 40 in the afternoon
Rain: 60%
Wind: SSE/NNW 20-25
...Marine Forecast...
*Small Craft Advisory in effect through Thursday.*
Tonight...Northeast winds around 20 knots. Seas 4 to 6 feet. A chance of rain.
Thursday...Northeast winds 15 to 25 knots becoming 20 to 25 knots in the afternoon. Seas 4 to 6 feet. Rain likely in the morning. Isolated thunderstorms. A chance of rain in the afternoon.
Thursday Night...North winds 15 to 25 knots becoming 15 to 20 knots after midnight. Seas 4 to 5 feet subsiding to 3 to 5 feet after midnight. A chance of rain in the evening.
Friday...North winds 10 to 15 knots. Seas 3 to 5 feet subsiding to 2 to 4 feet in the afternoon.
Friday Night...Northwest winds 10 to 15 knots becoming north 15 to 20 knots after midnight. Seas 2 to 3 feet building to 3 to 4 feet after midnight.
Saturday...North winds 15 to 20 knots. Seas 2 to 4 feet.
...Tide Data...
Thursday Tides @ Calcasieu Pass
Low: 8:50a.m. 9:11p.m.
High: 4:47a.m. 11:11p.m.
Good night and God bless!
-DM-
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