Sunday, November 15, 2009

Strong Cold Front Arrives Monday Morning...Chance of Showers & Thunderstorms, but No Severe Weather...Coolest Weather of the Season for Mid-Week...

Sunday, November 15, 2009

SW Louisiana Forecast Discussion...It was a dry, fairly nice weekend across the forecast area. A warming trend ensued as high pressure slid off to our East. Gulf moisture increased as winds returned to a Southerly component in response to the departing high. Aside from some areas of patchy fog, and high clouds on Saturday, and an increase in mid and low level clouds today (Sunday) the string of nice weekends continued. An increase in low-level moisture and humidity was noted. Temperatures were unseasonably warm with highs in the upper 70s both days, while lows moderated from the lower 50s on Saturday to the lower 60s this morning. Our next cold front is in transit at this hour stretching from the Rio Grande Valley into the Mid-West. The front is making very good progress to the SE, and will be moving into our area during the day Monday. Ahead of this boundary, low-level moisture will continue to increase. Skies will become Overcast overnight. Some patchy fog can't be ruled out with relatively light winds in place across the forecast area. A few light showers will develop and be scattered at random across the forecast area by sunrise. Mild temperatures will remain in place with fairly uniform low temperatures bottoming out around 60. A slight chance of a shower will be indicated in the official forecast for the early morning hours of Monday.

Rain chances will increase Monday morning as the front nears the area. It will continue making steady progress from NW to SE, and have no trouble pushing through. The upper level flow favors a quick moving front, and this is what is forecast. As the front feeds into the moisture over the area from the Gulf of Mexico, showers and some thunderstorms will become more numerous and reach the likely category. Instability is present for some thunderstorm development, but dynamics with this system will be displaced well North of the forecast area, so no severe weather is anticipated. Due to the fast moving nature of the front, rainfall totals will not be overly heavy. Average amounts should be around .5", but some locations could see as much as an inch. Rainfall should begin impacting the area around mid-morning Monday as the front approaches. The best chance of a thunderstorm will come along and ahead of the front most likely between 9a.m. and noon. The front will quickly move through the forecast area, entering NW portions of the forecast area by sunrise, and into SE Texas by mid-morning, pushing through Lake Charles before noon, and then into Acadiana early afternoon. Showers will continue for a few hours behind the front, as the dry air aloft lingers for a bit behind the departing trough and front. An upper level low on the back side of the system will be moving through the Red River Valley during the day, and this will hold up the arrival of the drier air in the upper levels for a short time. Rainfall will come to an end Monday evening. The onshore flow will continue until frontal passage, and by noon Monday winds will shift from onshore to offshore with strong Cold Air Advection taking shape. Temperatures will rise only slightly with the expected rainfall, and early arrival of the front. Highs should reach the upper 60s to lower 70s, with some mid 70s possible for Acadiana, where the colder air will arrive last. Temperatures will fall off during the afternoon behind the front, so I expect highs to occur from late morning to around noon. Temperatures should be in the 50s by Monday evening. It will turn quite windy behind the front with wind gusts as high as 25 mph at times in response to the pressure differential with the advancement of the front. Clear skies and colder temperatures will take over Monday night.
















The coldest weather thus far this season will be ushered in with this front, and to illustrate this just compare temperatures on each side of the boundary. Here in Lake Charles, at 9p.m. it is 64 while in the Texas Panhandle at Amarillo it is 34 with some snow expected later on. Of course, we won't see any snow here, but certainly may need a coat or jacket by Tuesday morning. As skies clear overnight Monday into Tuesday morning, and strong Canadian high pressure begins to build in temperatures will fall off into the low to mid 40s by sunrise Tuesday. With gusty NNW winds on the order of 15-20 mph continuing, we'll be talking about a wind chill for Tuesday morning. It feel like its in the 30s, so there will certainly be a definitive nip in the air. The strong high pressure will build in over Texas Tuesday while the backside ULL resides over the Ozarks. The winds will slacken during the day. Despite sunny skies, temperatures will struggle to warm up much with strong CAA in place. Afternoon highs will range from the upper 50s across the Northern extremities of the forecast area, to the mid 60s along the coast. Lower 60s seem like a feasible value for the I-10 corridor. The coldest night of the season is on tap for Tuesday night/Wednesday morning as high pressure builds in right overhead. Winds will drop off to very light or dead calm. This will set the stage for maximum radiational cooling conditions. With dew point temperatures dropping well into the 30s Tuesday afternoon, overnight lows will range from the upper 30s for Fort Polk and Alexandria to the mid 40s at the coast. Lower 40s are forecast for the I-10 corridor from Beaumont to Lafayette. Oft times temperatures in the upper 30s can be cold enough for frost, but with the low dew points and dry air in place, frost is not anticipated at this time for Northern portions of the forecast area.

Wednesday-Friday...Great fall weather is expected for Wednesday and Thursday as the large Canadian high pressure dominates. Wall-to-wall sunshine is expected, with temperatures remaining below normal. After the upper 30s to lower 40s on Wednesday morning, maximums will reach the mid 60s. Modification begins by Thursday as the high pressure begins to slide East of the Mississippi River. Another chilly morning well down into the 40s is in store for Thursday, but as a light return commences during the day expect afternoon highs to reach near 70. Modification of the Canadian air mass continues Thursday night as the high slides further East, and the onshore flow become more prominent. Low temperatures will be in the low to mid 50s across the area. Clouds will increase on Friday as another front approaches the area. There is still some deliberation from the models as to how much moisture availability there will be. This is certainly part of the forecast that will likely be fine tuned as the week progresses. At this time, I believe there will be enough low-level moisture return, to insert a small chance of showers into the forecast for Friday, but no thunderstorms with no dynamics present. It is the lifting mechanism itself that will displace the available moisture. Timing of this front is still uncertain as well, but at present it looks to occur between late morning and early afternoon. A fresh air mass will move in behind this front, though it will contain more of a Pacific air mass, so temperatures should not cool off as dramatically behind this second front. Friday high temperatures will be in the low to mid 70s...very near seasonable for the second half of November.

Saturday-Sunday...The pre-Thanksgiving weekend is looking decent at this time. Seasonable weather is expected both days with lows in the upper 40s to lower 50s, and highs in the lower 70s. Sunny skies should prevail for Saturday with high pressure in control, but a very progressive weather pattern will become established across the contiguous 48 states later this week. The high will quickly slide East of the state on Saturday afternoon inducing the onshore flow once again. Models indicate a vigorous trough, and associated cold front and surface low moving into the Rockies at this time. This system may continue intensifying as it comes out the Rockies and into the Great Plains on Sunday. Sunday should remain dry for our area with plenty of sunshine, but clouds and Southerly winds will increase during the day. Some return flow showers could occur by the end of the day Sunday, but this is not forecast at this time. The aforementioned vigorous storm system will likely effect our area Monday the 23rd. There has been much consistency in this idea from the forecast models. This is 8 days out, and it is hard to be specific about what to expect at this point, but some indications are that there will be a severe weather and heavy rain threat with this system. I'll analyze this system further later this week, as I get a better idea on its evolution. This will take us into Thanksgiving week, and the weather pattern appears to stay progressive, and perhaps favor colder just in time for Thanksgiving, but again its hard to be specific at this point, and I use the usual disclaimer with anything beyond 7 days....subject to change!!! We'll have the first sneak peek of an official Thanksgiving forecast later this week.


Tropics: Unlike a week ago tonight, the tropics are quiet, and will stay that way.


Preliminary Numbers & Zone Forecast:

LCH   61/71   45/62   42/65   20 70 0 0 0 0
LFT    61/74   44/61   41/66   20 70 0 0 0 0
BPT    63/68   46/63   43/66   30 70 0 0 0 0
AEX   60/65   41/59   37/63   20 70 0 0 0 0
POE   60/64   42/60   38/63   20 70 0 0 0 0
ARA   62/75   45/64   43/66   20 70 0 0 0 0


Tonight...Increasing Cloudiness. Becoming Mostly Cloudy with a 20% chance of showers towards sunrise. Low 61. SSE wind 5-10 mph.

Monday...Cloudy with showers and thunderstorms developing in the morning, and becoming likely by late morning. Rain ending late afternoon. Turning Windy and Cooler. High 71 with temperatures falling into the upper 50s to lower 60s by late afternoon. Rainfall totals an inch or less. SSW wind 10 mph early, becoming NNW at 15-25 mph and gusty by afternoon. Chance of rain 70%.

Monday Night...Decreasing Cloudiness, Windy, and Much Colder. Becoming Clear overnight. Low 45. NNW wind 10-15 mph. Wind chill readings 35-40 by sunrise Tuesday.

Tuesday...Sunny and Breezy. High 62. NNW wind 10-15 mph diminishing in the afternoon.

Tuesday Night...Clear. Low 42. NW wind 5-10 mph.

Wednesday...Sunny. High 65. North wind 5-10 mph.


Drew's 7 Day Outlook for Lake Charles & Vicinity


Monday
11-16-09







Low: 61
High: 71
Rain: 70%
Wind: SSW/NNW 15-25


Tuesday
11-17-09







Low: 45
High: 62
Rain: 0%
Wind: NNW 10-15
W.C.: 35-40 AM


Wednesday
11-18-09







Low: 42
High: 65
Rain: 0%
Wind: N 5-10


Thursday
11-19-09

Low: 47
High: 71
Rain: 0%
Wind: NE/SE 5-10


Friday
11-20-09

Low: 52
High: 73
Rain: 30%
Wind: SSE?/NNW 10-15


Saturday
11-21-09

Low: 48
High: 70
Rain: 0%
Wind: N 5-10


Sunday
11-22-09

Low: 53
High: 75
Rain: 0%
Wind: NE/SE 10-15


...Marine Forecast from NWS Lake Charles...

*Small Craft Advisory from Noon Monday through Noon Tuesday.*

Tonight...South winds around 10 knots. Seas 2 to 3 feet. A slight chance of showers and thunderstorms.

Monday...Southwest winds 10 to 15 knots becoming northwest 15 to 25 knots in the afternoon. Seas 2 to 3 feet building to 3 to 5 feet in the afternoon. Showers and thunderstorms likely.

Monday Night...Northwest winds 20 to 25 knots becoming north 15 to 20 knots after midnight. Seas 4 to 6 feet.

Tuesday...Northwest winds 15 to 20 knots decreasing to 10 to 15 knots in the afternoon. Seas 4 to 5 feet.

Tuesday Night...Northwest winds 10 to 15 knots becoming north 5 to 10 knots after midnight. Seas 2 to 4 feet.

Wednesday...Southeast winds 10 to 15 knots. Seas 2 to 3 feet.


...Tide Data...

Monday Tides @ Calcasieu Pass:

Low:    7:57a.m.
High:    3:26p.m.


...Toledo Bend Pool Level...
    172.37'


...Lake Charles Climate Summary...

Low:                61
Normal Low:   50
Record Low:   25-1969
High:               80
Normal High:  71
Record High:  88-1917

Rainfall
Today:                            0.00"
Month to Date:               0.05"
Normal Month to Date:  2.23"
Year to Date:               61.99"
Normal Year to Date:  50.21"
Record:                         4.05"-1914


Sunrise Monday:     6:39a.m.
Sunset Monday:      5:16p.m.

Hunting Times:        6:09a.m.-5:46p.m.


...Lunar Table...

New Moon- November 16

First Quarter- November 24

Full Moon- December 2

Last Quarter- December 9


Good night and God bless!
-DM-

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