SW Louisiana Forecast Discussion...As we close out the Thanksgiving holiday weekend, I hope everyone had a great time with family and friends. What kind of weather can we expect as we close out November, reach the end of the 2009 Atlantic hurricane season, and the start of meteorological winter? As we close out the Thanksgiving holiday weekend changes are bountiful. After a cold and clear start to the holiday weekend, a significant warming trend has occurred on the back end with a pronounced return flow off the Gulf out ahead of a vigorous trough and attendant cold front. Clouds increased at all levels across the forecast area today, and as people head home from the holiday conditions are dry, but it is overcast the entire forecast area. Temperatures warmed from the 30s for lows at the beginning of the holiday weekend, to the 50s this morning, while afternoon highs warmed from the upper 50s and lower 60s to the unseasonably mild mid to upper 70s. The mild trend will continue overnight as the cold front impinges on the forecast area. Expect temperatures to hold in the 60s overnight for most, but as the cold front enters the extreme Northern portion of the forecast area, temperatures will fall into the 50s in this area. The front currently stretches from near San Antonio to Tyler to Texarkana to near Jonesboro, AR. Rain and a few thunderstorms are occurring along and behind the boundary. The front will make steady progress to the SE overnight, and be near a Houston to Shreveport line overnight, and from a Lake Charles to Monroe line by 6a.m. and a Lafayette to Jackson, MS line by 10a.m. A few showers will be noted across the forecast area overnight ahead of this boundary, but the majority of rainfall should occur behind the front. A few sprinkles or light showers are beginning to develop at this time as moisture continues to increase ahead of the boundary. For the most part, conditions should be dry until after midnight.
A significant rainfall event unfolds as we get into Monday. Showers and a few thunderstorms will become more prominent as the boundary nears and convergence increases. Behind the front, CAA will take over and temperatures will begin to decline. Rain chances will ramp up significantly around daybreak, first for the convergence zone ahead of the front, and then for the overrunning that will occur behind it. A strong SW flow aloft will remain in place in the upper levels behind the front, and this is what will result in our rain event for Monday. The significant rainfall expected this week is really a two-parter. The first part is with the front, and the overrunning behind it for Monday. The persistent SW flow will hang around for awhile, because of a slow moving Upper Level cut off from the main flow across the country. This low is currently over Baja California. The SW flow aloft will keep warm air riding up and over the cool air filtering in at the surface. The cool air will filter into the forecast area during the day Monday, and as a strong CAA pattern is established temperatures will begin to fall Monday morning as the rain falls. The morning temperatures will be in the lower 60s, and Monday will be a day where the high occurs between midnight and 6a.m. most likely. Temperatures will fall from the lower 60s to the lower 50s by the end of the day. The first round of rain will taper off Monday afternoon as the front slips further into the Gulf, and drier air temporarily filters into the mid and upper levels. Rain chances will not be eliminated entirely as a moist layer will remain in place as winds remain from the SW aloft, and CAA with NNE winds continues at the surface. Cloudy skies will remain even after the rain tapers off Monday. It will become quite breezy as well with a significant pressure differential behind the front. CAA continues Monday night and temperatures fall off into the 40s, but the cooling potential will be limited due to the cloud cover and periodic showers. Rainfall percentages will be highest Monday morning through early afternoon as periodic perturbations embedded in the SW flow aloft rotate through behind the front. For the remainder of the day, rain chances will be tempered downward with only a small chance in place for Monday night with the brief reprieve. Rainfall amounts across the area for the first round should be about an inch or so with isolated higher amounts up to 3" possible.
Cold, wet, and windy will be the weather conditions through mid-week. Tuesday will be almost the opposite of Monday as far as the timing of rainfall. The ULL will slowly trudge Eastward across the Rio Grande Valley of South Texas and Old Mexico through Monday. It will work in tandem with energy from the Subtropical Jet to initiate cyclogenesis off the Texas coast late Monday night. This will cause an additional surge of Gulf moisture to override the cool layer of air at the surface. CAA will be continuing all the while. Tuesday should start dry for the most part with just cool and overcast conditions in place. The wind remain an issue as well. In fact, it will likely only get stronger Tuesday as the Gulf low strengthens and treks towards South Louisiana. The end result will be a very small diurnal range with temperatures likely not exceeding 50. Rain will overspread the area by Tuesday afternoon as the low lifts NE. The low will track NE along the frontal boundary, which will stall, over the Gulf. The eventual track of this low will dictate how much rainfall we see for the second go-around. Rain will certainly heavier and more likely across the Southern tier of the forecast area, but rain chances will be on the high side for the entire forecast area. As of right now; based on the prognosticated track of the low the worst weather with this system should remain over the Gulf, but certainly heavy rain will be possible along and south of the I-10 corridor. Severe weather isn't anticipated at this time with either event. That being said, some thunderstorms can't be ruled out even in the cool, stable atmosphere over the forecast area with the CAA continuing. Some elevated convection could develop, and some rumbles of thunder may occur. Rain will become likely Tuesday afternoon, and remain high overnight Tuesday into early Wednesday as the low approaches the coast before evacuating to our NE. Rain chances will nearly max out during this time frame. Windy conditions will prevail as mentioned previously with winds out of the NNE in the 20-30 mph at times. Even stronger winds are expected in the offshore waters with high waves and seas. This will be the type of system that is very definitive of an El Nino regime along the Northern Gulf Coast. Rainfall amounts with the secondary part of this rain maker should be on average of 1-2" with higher amount up to 4" possible by the time the event winds down on Wednesday. There could be some coastal flooding issues as well as some localized urban flooding depending how much rain we get, but this is something that will be fine tuned on Monday.The graphic below depicts the expectant rainfall amounts for the week.
The rain will end on Wednesday, but the cold weather will stick around. It will truly feel like early December. Can you believe it's going to be December already? CAA will remain in place, but drier air will move in at all levels as the low moves up into the Central Gulf Coast region Wednesday morning. The rain will end in a graduated fashion from West to East across the forecast area on Wednesday. In its wake, the clouds will hang tough for the remainder of the day, and it will be another cold and blustery day with a small diurnal range expected. I don't expect temperatures to get out of the 40s on Wednesday either with lows in the low 40s and highs in the mid to upper 40s. The strong winds will produce a wind chill for the Tuesday-Wednesday period as well. While the actual temperature will be in the 40s, wind chill readings for each day will be in the 30s at times. High pressure will replace the departing low for the latter half of the work week, and this will help to erode the cloud cover across the forecast area in the Wednesday night time frame. A cold Canadian high pressure building in out of the Canadian Provinces will result in the coldest weather so far this season. Temperatures for Wednesday night will be in the 30s area wide with Northern portions of the area getting very close to freezing by sunrise Thursday morning. The remainder of the area should be in the frosty category with the exception of the coast. Mid 30s seem logical for the I-10 corridor, similar to this past Friday. As the high pressure builds in, winds will calm down as well, however, it won't be until Thursday that they go nearly calm. Wednesday night/Thursday morning will still feature a wind chill with winds out of the North at 10-15 mph. Wind chill readings could be in the 25-30 degree range by sunrise Thursday.
Thursday and Friday will be beautiful and cool. Thursday will remain quite cool. Under sunny skies, temperatures will not eclipse the 60 degree mark, likely topping out somewhere in the 50-55 range. Thursday night/Friday morning will bring the coldest temperatures so far this season as high pressure penetrates the Northern Gulf Coast. I would expect a pretty good freeze for the Northern portions of the area with some upper 20s not out of the realm of possibility. 30s will be experienced elsewhere, with the chance for a light freeze down to I-10. I will keep temperatures above freezing for the time being for Friday's minimum at least for Lake Charles & Vicinity, but a freeze is very likely at locations like Alexandria, Fort Polk, Oakdale, DeRidder, Jasper, Silsbee, Bunkie, Opelousas, and Marksville. Either way it will be cold, and I'll refine this forecast as we go through the week. A modest warming trend begins Friday afternoon with readings reaching the 55-60 degree range.
Benign weather remains in place for the Friday night/Saturday time frame. The high will slide Eastward during the day Friday with a return flow commencing Friday night. Therefore, temperatures will not be as cold Friday night. Temperatures should remain well above freezing across the area with upper 30s to mid 40s expected. A more pronounced return flow and warming trend ensues Saturday as the high keeps moving Eastward, and yet another front develops in the lee of the Rockies. Saturday should remain dry, but clouds will increase as we get into the afternoon. Temperatures will reach the low to mid 60s for Saturday afternoon with Southerly winds intensifying ahead of the next front. The next rain chance enters into the scheme of things at the end of the forecast period next Sunday. This, as the next cold front works through. A decent shot of rain is possible with this front, but it looks like a quick mover. The air behind this front doesn't look near as cold since this should be more of a Pacific air mass. Sunday temperatures will be mild ahead of the boundary with morning lows around 50 to the lower 50s, and highs a tad warmer than Saturday ahead of the front. The usual timing differences are present this far out, so I'll be more specific as we get closer. Beyond the forecast period, an active weather pattern should remain in place through the first half of December. December is rarely a boring weather month around here, and this should hold firm in an El Nino year.
Tropics: The season officially ends Monday. So, does this section of the blog until June 1, 2010.
Preliminary Numbers & Zone Forecast:
LCH 66/51 45/48 42/46 70 70 30 90 100 60
LFT 63/52 45/50 41/46 70 70 30 80 100 70
BPT 66/50 46/49 42/47 70 70 30 90 100 60
AEX 63/49 43/47 40/45 80 70 20 80 90 60
POE 63/49 44/48 40/45 80 70 20 80 90 60
ARA 64/53 46/51 43/48 70 70 30 80 100 70
Tonight...Mostly Cloudy with showers and thunderstorms likely after midnight. Mild with temperatures holding in the mid 60s. SSW winds 10-15 mph. Chance of rain 70%.
Monday...Cloudy, Windy, and Turning Colder with showers and thunderstorms likely, tapering off in the afternoon. High around 62 early with temperatures falling through the day into the lower 50s by late afternoon. SSW wind 15-20 mph and gusty early, becoming NNW at 15-20 mph and gusty in the morning. Chance of rain 70%. Rainfall totals around 1" on average with higher amounts up to 3" possible.
Monday Night...Cloudy and Windy with a 30% chance of rain. Low 45. NNE wind 15-20 mph and gusty.
Tuesday...Cloudy, Windy, and Cold with rain becoming likely by afternoon. Heavy rain at times. High 48. NNE wind 15-20 mph and gusty. Chance of rain 90%.
Tuesday Night...Cloudy and Windy with Rain likely. Rain heavy at times. Low 42. NNE wind 15-20 mph anf gusty. Chance of rain 100%. Wind chill readings 30-35 by morning.
Wednesday...Cloudy and Windy with Rain Likely in the morning. Rain ending in the afternoon. Cold. High 48. North wind 20-25 mph and gusty. Chance of rain 60%.
Drew's 7 Day Outlook for Lake Charles & Vicinity
Monday
11-30-09
Low: 66
High: 51
Rain: 70%
Wind: SSW/NNW 15-20
Tuesday
12-1-09
Low: 45
High: 48
Rain: 90%
Wind: NNE 15-20
W.C.: 30-40
Wednesday
12-2-09
Low: 42
High: 46
Rain: 60%
Wind: N 20-25
W.C.: 30-40
Thursday
12-3-09
Low: 36
High: 53
Rain: 0%
Wind: N 10-15
W.C.: 25-40
Friday
12-4-09
Low: 33
High: 56
Rain: 0%
Wind: NE 5-10
Saturday
12-5-09
Low: 40
High: 62
Rain: 0%
Wind: SE 10-15
Sunday
12-6-09
Low: 52
High: 65
Rain: 60%
Wind: SSE/NNW 15-20
...Marine Forecast...
*Small Craft Advisory Monday through Wednesday.*
Monday...Northwest winds 15 to 20 knots becoming northeast 20 to 25 knots in the afternoon. Seas 2 to 3 feet building to 3 to 4 feet in the afternoon. Showers and isolated thunderstorms in the morning...then a chance of showers in the afternoon.
Monday Night...Northeast winds 15 to 20 knots. Seas 3 to 4 feet. A chance of showers in the evening...then showers likely after midnight.
Tuesday...Northeast winds 15 to 20 knots becoming 15 to 25 knots in the afternoon. Seas 4 to 6 feet. Showers likely.
Tuesday Night...Northeast winds 15 to 20 knots becoming northwest after midnight. Seas 3 to 5 feet subsiding to 2 to 3 feet after midnight. Showers likely.
Wednesday...Northwest winds 15 to 20 knots. Seas 3 to 5 feet. A chance of showers.
...Tide Data...
Monday Tides @ Calcasieu Pass:
Low: 6:40a.m. 8:17p.m.
High: 2:15a.m. 9:28p.m.
...Toledo Bend...
171.44'
...Lake Charles Climate Summary...
Sunday, November 29, 2009
Low: 56
Normal Low: 46
Record Low: 22-1911
High: 77
Normal High: 67
Record High: 88-1912
Rainfall
Today: 0.00"
Month to Date: 1.93"
Normal Month to Date: 4.46"
Year to Date: 63.87"
Normal Year to Date: 52.44"
Record: 3.14"-1977
Sunrise Monday: 6:51a.m.
Sunset Monday: 5:12p.m.
Monday Hunting Times: 6:21a.m.-5:42p.m.
...Lunar Table...
Full Moon- Wednesday December 2
Last Quarter- Wednesday December 9
New Moon- Wednesday December 16
First Quarter- Thursday December 24 (Christmas Eve)
Good night and God bless!
-DM-
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