The forecast discussion is coming up, and it'll be quite lengthy as we have 3 systems on the docket this week including one in the short-term. First, I wanted to take some time to rehash the historical day we had on Friday with our earliest snowfall on record. It was a day none of us will ever forget no matter how much snow you got at your particular location.
As I begin to rehash this event, I guess I should first state that things really began coming together last Monday (30 November). Forecast models, mainly the GFS, began latching onto the idea of snow along the Gulf coast sometime in the Friday/Saturday time frame. I scoffed at this idea at first for umpteen reason. One being that it rarely happens in the South anyway. Secondly, it seemed premature beings it was only early December, and would come a week earlier than the record snowfall set last year on December 11. Thirdly, as is often the case in an El Nino pattern, the models can overdo things. Next, I questioned how much moisture would be available at said time because of a cold dry period in place. Lastly, I thought perhaps it was some bad data incorporated into the model algorithm. However, this was not the case after all...
The model was very persistent in the idea of some snow as another system embedded in the quick upper level flow in this El Nino would form. The model suggested a low would form in the Gulf as well, and at the same time a blast of Arctic air would be dislodged over Canada and spew Southward towards the Gulf coast. At first, it could've been construed as a fluke or a mistake, but after several model runs showed the idea of snow occurring, it simply couldn't be ignored. The models run four times a day, and the longer it persisted with each run, it seemed as though the likelihood of some snow was increasing. I began to address the idea of some winter precipitation, albeit loosely, on the blog beginning Tuesday. On Wednesday, confidence increased further as more models were insistent on some snow. It began to seem logical to me at this point after analyzing the expected upper level data for the Friday afternoon forecast period. So, I went for it, and began mentioning the s word in the forecast at this point. It was certainly a set up that favored snow as opposed to sleet or freezing rain, which is a tad more likely around here.
I was still strongly skeptical because forecasting winter precipitation, much less snow, around these parts is simply no easy feat. It became a question of whether or not the cold air would arrive in time before the precipitation ended or not. There was no doubt that there would be another system coming across the area via the Jet Stream, and that it would rain on Friday. More often than not with winter weather situations across our area, it is often a case of will the precip hang around long enough or will the cold air be delayed until after the precip vacates the premises. The confidence in seeing some snow continued to increase into Thursday as everything seemed to be setting up perfectly for history to occur in the forecast area. The confidence was high enough that the National Weather Service issued a Winter Storm Watch for the forecast area on Thursday morning. This suggested that some accumulation of snow was possible across the forecast area Friday into Friday night. As the event drew nearer, the forecast was revised further, which is always expected to happen with winter weather. The Winter Storm Watch was upgraded to a Winter Storm Warning for all parishes and counties north of I-10, while all parishes and counties to the South of I-10 were placed under a Winter Weather Advisory. By Friday, it was just simply a matter of looking out the window, and just a lot of watching and waiting. Snow began falling in the Houston area Friday morning...
Cold air was in place as the event began, but the cold air was a bit deeper back to our West, therefore, mostly snow occurred in the Houston area, while upstream across our area, it began as a cold rain. Based on forecast data, the time line was for rain Friday morning, mixing with snow Friday afternoon, before becoming all snow Friday evening before ending in the overnight hours into early Saturday. This was very close to what actually occurred. Total accumulations were expected to be an inch or less along and South of I-10 while as much as 2-3" of snow could occur North of I-10. Forecast models suggested that the heaviest snow would occur in the Winter Storm Warning area. It would all depend on the track of the Gulf low.
Temperatures on Friday morning under overcast skies were generally around 40 to the mid 40s across the area. As rain overspread the forecast area before noon, temperatures would slowly fall into the 30s throughout the day as the cold Arctic high settled into North Texas. Rain was expected for the duration of the day as the Gulf low and attendant upper level disturbance moved through. As the colder air moved in, snow began mixing in with the rain by late morning across the Western and Northern portions of the area with the first snowflakes in Lake Charles spotted around noon. A transition to all snow would occur early to mid-afternoon for Northern and Western areas, while it took a little longer for the rest of the area. Precipitation transitioned to all snow around 5p.m. in the Lake Charles area, and by 7p.m. for Acadiana. There's no such thing as a perfect forecast when dealing with winter weather, but the set up was perfect for accumulating snow. Limiting factors were the wet, warm ground, and the movement of the system. The system began speeding up as it approached the Sabine River as it got an extra kick from the Jet Stream. This limited snowfall amounts across the area. If the system had continued moving at the pace it was earlier in the day, then we would have seen quite a bit more snow. Since, the system sped up, the precipitation ended sooner than expected. However, enough snow fell that many records were established. Snow fell all the way to the coast, even though only trace amounts occurred there. The accumulation amounts were right in the line with the expected forecast for up to an inch along I-10 and 2-3" North of I-10. Snow fell for up 4-6 hours across the Northern half of the forecast area, and 2-4 hours for the remainder of the area. Snow ended in Lake Charles around 8p.m. Friday evening. It snowed long enough in town to coat car tops and roofs with plenty of snow, and many yards across town were white. Much of the snow melted shortly after the precip ended since temperatures were just above freezing, and the ground was a bit warm. However, much of the snow that collected on cars and other surfaces above the ground remained into Saturday morning. Where the snow was heavier, in places such as DeRidder, Oakdale, and Eunice, snow remained on the ground through Saturday morning. Very cold Arctic air was in place behind the snow with freezing temperatures experienced all the way to the coast. All of the snow is now just a memory engraved in our minds and hearts forever. I hope everyone had a chance to enjoy it. The snow was historic for SW Louisiana, where it is more of an anomaly than anything to begin with. It marks the earliest such occurrence of accumulating snowfall in SW Louisiana since records began back in 1891. Here are some notes about the snowfall from Friday, December 4. This information comes courtesy of the National Weather Service Lake Charles.
Lake Charles:
Earliest recorded snowfall on record---0.2" at the LCH Airport (old record 0.4" on 12/11/08)
Snowfall totals across Lake Charles range from 0.2" to near 0.6". I recorded 0.4" of snow here at my house.
Ties for second heaviest December snowfall on record (0.2" on 12/22/89)
Only the third time in recorded history that measurable snow has occurred n Lake Charles during the month of December.
First such occurrence of measurable snow in back-to-back years in Lake Charles during the month of December. Snow was recorded in back-to-back years in January of 1948 and 1949.
Alexandria:
Second earliest measurable snowfall on record. All-time record for earliest snowfall @ AEX is 12/2/1896.\
Fifth highest snowfall total for the month of December (0.2").
Only the fifth such occurrence of measurable snow in December.
Lafayette:
Earliest measurable snowfall on record (0.3" @ LFT) Old record established just last year on 12/11/08 (1").
Second highest snowfall amount for the month of December @ 0.3".
Only second such occurrence of measurable snow in December. (2008).
Only trace amounts of snow occurred at the official reporting sites in Beaumont and New Iberia.
Selected snowfall amounts across SE Texas/SW Louisiana via NWS LCH.
5 Miles N of Silsbee, TX 2.5"
Kountze, TX 2"
Lumberton, TX 1"
Beaumont, TX 0.3"
Eunice, LA 3"
Fort Polk, LA 2.5"
Rosepine, LA 2.5"
Anacoco, LA 2"
DeQuincy, LA 2"
Leesville, LA 2"
Ville Platte, LA 2"
Lacassine, LA 1.5"
Welsh, LA 1.5"
Carencro, LA 1"
Plaisance, LA 1"
Jennings, LA 0.8"
Lake Arthur, LA 0.5"
Lafayette, LA 0.3"
Lake Charles, LA 0.2"
Alexandria, LA 0.2"
Moss Bluff, LA 0.2"
There's nothing like pictures to help illustrate how beautiful this snow was. Here are some submitted by some friends.
Nice Snowman in South Lake Charles...submitted by Jessica Lofton, Lake Charles.
More snow pics from South Lake Charles...submitted by Amanda Guidry, Lake Charles
Tiny snowman. in LC- Amanda Guidry
Writing the date in the snow in Lake Charles---Amanda Guidry
Thank you for your pics! If anyone out there has pics they would love to share, please do. E-mail me @ BestWxMan1980@yahoo.com. I will post them here as I get them.
The following comes from the National Weather Service:
This map shows the snowfall accumulations across the area.
This image may be hard for you to see, but if you look closely you can see the snow on the ground across the area on Saturday morning with clear skies.
I hope to have more pics in the coming days of this historic event. As is, so often the case with a snow event, whether it be here or anywhere, there are often many people who are beyond elated, and others who are disappointed, but that's just the way it goes with snow. If you missed out on snow this go around, or wanted more than you got, don't give up hope, maybe we'll have another chance before the winter is over. After all, it has snowed 2 years in a row now after nearly a 20 year drought. I thank all of you who trusted my forecast for snow. I am humble enough to admit that I still have much to learn when forecasting winter weather, and I hope I get that chance later on in the winter. I am up to that challenge, and I will strive to always do my best for you. See the forecast below!
SW Louisiana Forecast Discussion...The snow is a distant memory now! It will be a very active week weather wise across the Gulf Coast, but no snow. The entrenched Arctic air mass is eroding tonight as milder Gulf moves into the area ahead of our next weather maker. This will be the first of three systems to affect the area this week. A zonal flow (W to E) is established across the area at this time. The very progressive El Nino pattern will continue as yet another Gulf low and associated frontal boundary will work in tandem to bring rain back into the area. Clouds increased across the area over the weekend while the chilly weather prevailed. Since the area wide freeze on Saturday morning, air mass modification has occurred with highs reaching the mid 50s this afternoon. The first weather system is ongoing tonight with a shield of rain and embedded thunderstorms moving up the Texas coast as the low progresses through the Gulf waters. Rain will be likely across the area after midnight through early Monday as a result of this system. Rain chances will be highest near the coast, and be tempered downward further inland. Temperatures reached the mid 50s this afternoon, and really won't change much tonight, maybe or degree or two. Temperatures could even rise a bit as a WAA regime strengthens over the forecast area. Rainfall totals between now and 6a.m. Monday should be an inch or less. This will be a fast mover, and it should be out of the area shortly after sunrise Monday. The associated Pacific front with this system will sag into the Gulf waters Monday morning before stalling.
The rain ends temporarily on Monday morning, and clouds remain entrenched as the front stalls in the Gulf as advertised. Temperatures will reach the 60s with ease on Monday. Rain chances return late Monday afternoon through Monday night as the staled front retreats Northward as a warm front. This will quickly bring the chance for showers and thunderstorms back to the forecast area. This should set the stage for a more significant system across the area as we get into the warm sector and strong WAA. This round of rain will commence by late afternoon, and continue through the night into Tuesday in the warm sector. Another Pacific cold front will be in transit at this time. This will be a more robust system, and by far the strongest of the three systems to affect us this week. Some severe weather in the warm sector can't be ruled out overnight Monday into Tuesday. Monday highs will continue to moderate with expected maximums well into the 60s, and could very well reach the 70s Tuesday believe it or not...5 days after accumulating snow!
The overnight Monday through Tuesday period also offers the threat for some severe weather. To what extent remains to be seen, but the set up is favorable for thunderstorms to ride along the warm front perhaps billowing up into a supercell thunderstorm with a hail and tornado threat. An additional threat for severe weather will come during the day Tuesday ahead of the Pacific front. This may be more a damaging wind/tornado threat, but there should be a severe weather possibility for the entire area for Tuesday. The forecast area is highlighted by the Storm Prediction Center for a Slight Risk of Severe Weather for Day 3 (Tuesday). Severe weather certainly seems possible in this system with a Pacific storm system moving in against a strong El Nino zonal flow in early December. Severe weather or not, there is the potential for heavy rainfall with a couple inches of rain not out of the realm of possibility. A re-assessment of the situation will be given on Monday, but rain chances will nearly max out for this time frame. The most likely time to see some severe storms on Tuesday will be between noon and 6p.m. as the Pacific frontal boundary works into the area. The storms come to an end Tuesday as the driving force ahead of the front, an upper level impulse pushes into the Mid West to Ohio Valley. The front will clear everything out for a couple of days.
A cooler and drier air mass will be ushered in behind this front in an established NW flow aloft. This flow will help tap into a bit of Canadian air, so a nice cool down is anticipated by mid-week with high pressure established for the Wednesday/Thursday period. Cool and dry weather will prevail for this period, and while a significant cool down is expected no freezing temperatures are anticipated except maybe at locations such as Fort Polk and Alexandria by Thursday morning. Starting with Tuesday night it will be drier and cooler with the temperatures by Wednesday morning running from the upper 40s to mid 50s. Wednesday will be sunny, but with decent amounts of CAA across the area, only a modest warm up is expected with highs reaching the mid 60s. The coldest night of the week should come on Wednesday night/Thursday morning as high pressure is in place right overhead. Readings should be in the 30s at most locations with lower 30s for Alexandria, mid 30s for Lake Charles, and upper 30s at Cameron. High pressure in place will provide for near perfection Thursday, albeit a bit on the cool side. Highs should be shy of the 60 degree mark. CAA will cease at this time as the NW flow aloft switches to zonal once again. The controlling high shifts to the East, and clouds return by Thursday night with yet another system waiting in the wings for Friday.
The end of the week system will be yet another very similar system to some of its predecessors. However, at this time it appears to be much weaker, and only a small chance of rain is retained for right now. Moisture could be somewhat limited with the departing mid-week high slow to move. Gulf cyclogenesis is anticipated once again along the old front, but how strong remains to be seen. A small chance of showers and a few thunderstorms is inserted in this time frame, but this one should also be a fast mover. It should remain on the cool side Friday. Morning temperatures will have moderated considerably into the mid to upper 40s while afternoon highs reach the mid to upper 50s. This third system should be a quick mover with conditions improving to start the weekend Friday night. At this time, next weekend is looking fairly nice with seasonably cool temperatures with highs in the 50s and 60s and sunny skies. Another round of 30s seems feasible for Sunday as the high pressure behind this system builds directly overhead. The timing is great for any weekend activities whether it be Christmas related or something else. The progressive pattern doesn't come to an end with this system, as they will remained lined up to affect the region about every 3-4 days through mid-month at least. There are signs of some extremely cold weather entering the contiguous 48 states soon, but it is too early to speculate if it will reach the Gulf coast. The established zonal flow may keep it from doing so, but only time will tell. No snow anytime soon, that much is for sure.
This date in history will resume Monday.
Preliminary Numbers & Zone Forecast:
LCH 54/64 57/72 50/64 70 60 80 100 0 0
LFT 55/65 56/73 52/63 60 60 70 100 0 0
BPT 56/66 59/73 54/65 70 70 80 100 0 0
AEX 52/63 55/70 47/61 40 70 70 90 0 0
POE 53/63 56/71 48/62 40 70 70 90 0 0
ARA 56/65 60/74 50/65 60 60 70 100 0 0
Tonight...Cloudy with showers and a few thunderstorms likely. Near steady temperatures in the mid 50s. East wind 10-15 mph. Chance of rain 70%.
Monday...Cloudy with showers and a few thunderstorms early. A brief respite from the rain during the day. Rain re-developing late in the afternoon. High 64. Light East wind. Chance of rain 60%.
Monday Night...Cloudy with showers and thunderstorms likely. Some severe storms possible along with heavy rainfall. Low 57. East wind 10 mph. Chance of rain 80%.
Tuesday...Rain and thunderstorms likely. Some severe weather and locally heavy rainfall possible. Rainfall ending in the afternoon. High 72. SSW wind 10-15 mph. Chance of rain 100%. 1-2" of rainfall expected.
Tuesday Night...Clearing and Cooler. Low 50. NNW wind 15 mph and gusty.
Wednesday...Sunny. High 64. North wind 5-10 mph.
Drew's 7 Day Outlook for Lake Charles & Vicinity
Monday
12-7-09
Pearl Harbor Day
Low: 54
High: 64
Rain: 60%
Wind: E 5-10
Tuesday
12-8-09
Low: 57
High: 72
Rain: 100%
Wind: SSE/SSW 15-20
Wednesday
12-9-09
Low: 50
High: 64
Rain: 0%
Wind: NNW 10-15
Thursday
12-10-09
Low: 37
High: 55
Rain: 0%
Wind: N 5-10
Friday
12-11-09
Low: 46
High: 59
Rain: 40%
Wind: E 10-15
Saturday
12-12-09
Low: 42
High: 56
Rain: 0%
Wind: NNW 10-15
Sunday
12-13-09
Low: 35
High: 60
Rain: 0%
Wind: N 5-10
Monday...Southeast winds 5 to 10 knots. Seas 2 to 3 feet. Numerous showers and isolated thunderstorms in the morning...then scattered showers in the afternoon.
Monday Night...East winds 10 to 15 knots becoming southeast 5 to 10 knots after midnight. Seas 2 to 3 feet. Numerous showers and isolated thunderstorms.
Tuesday...South winds 15 to 20 knots becoming southwest 20 to 25 knots in the afternoon. Seas 2 to 4 feet building to 4 to 5 feet in the afternoon. Numerous showers and thunderstorms.
Tuesday Night...Southwest winds 15 to 20 knots becoming west 10 to 15 knots after midnight. Seas 3 to 5 feet subsiding to 2 to 4 feet after midnight. Isolated showers and thunderstorms in the evening.
Wednesday...Northeast winds 15 to 20 knots. Seas 2 to 3 feet.
The complete blog will return on Monday.
Good night and God bless!
-DM-
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