SW Louisiana Forecast Discussion...A very moist, unstable tropical air mass resides across the forecast area tonight. The rich tropical air mass will remain in place through the weekend. Showers and thunderstorms were numerous across the area today, and this trend will only increase for Friday through the weekend. With the deep moisture in place temperatures were held down to near normal to below normal levels, but the humidity was oppressive, look for this to continue as well for the next few days.
A large area of tropical moisture over the Western Gulf of Mexico remains in place tonight, and with an established Southerly flow this influx of moisture will continue streaming across the area through the weekend, with the entire area only moving slowly off to the NNE. A weak surface low appears to be developing in the vicinity of Brownsville, Texas. This area will be watched closely for possible tropical development on Friday. Models diverge on whether or not this system will develop into something tropical, but it should be noted that all the models do indicate a surface reflection of some sort. Conditions over the Gulf of Mexico are only marginally favorable for tropical development at this time with wind shear present at this time. The weak low will have to fight off the wind shear to develop into a tropical system. While there may be a surface low present at this time, there is some question as to whether or not it is a tropical low or not. The low is forming in response to energy from a surface trough over the Rio Grande Valley, and an approaching upper level disturbance coming out of the Rockies. The origin of the low may come over land, therefore, it may be a cold core system, whereas tropical lows are warm core systems. As the low attempts to strengthen it will try to garner tropical characteristics. It is uncertain what type of low and what degree this low will be as it moves slowly off to the NE over the weekend. It really won't make that much difference as far as our weather goes....wet! wet! wet! I would strongly suggest bringing your rain gear with you to any football games you may be attending this weekend. All the High School games on Friday stand a chance to be played in a downpour as does LSU on Saturday night. McNeese plays out of town this week, so rain won't be an issue for them.
The best forecast right now is that this low will be a hybrid system...that is, a subtropical low. What this means is that the low will not be fully tropical. It will have some of the characteristics of a tropical system, and some that are not typical of tropical systems. It will have a hard time getting going thanks to the shear that is present over the Gulf, but stranger things have happened in September in the Gulf, and if you remember it is prime time right now. In fact, today is the historical peak of hurricane season. This low will be affecting the area on the 12th and 13th, and we have had some notable storms during this time in recent years...Humberto in 2007 and Ike in 2008...both of which made landfall on September 13. The low will work in tandem with the upper level low over Texas to produce the heavy rainfall event. If the low strengthens, it may reach tropical depression or even weak tropical storm status over the weekend before it moves inland over the area Sunday. Winds and seas in the coastal waters would increase the more this low strengthens, and wind would become an issue for coastal areas as well as the low approaches. However, genesis of a tropical system is not expected at this time as the shear environment over the Gulf should preclude such an occurrence. As it typical with low pressure systems, the worst of the weather will be on the NE side of the low. This is, of course, the position we will be in the next 3 days. We will be in prime position to receive several inches of rain across the entire area. Rainfall amounts will vary from location to location, but average amounts should be 4-8". It won't be out of the realm of possibility that some locations receive upwards of 12" of rain through Sunday. We could use a little bit of rain, as it has been a dry September so far, but areas that desperately need the rain i.e. Central and South Texas will benefit greatly from this system. This will likely lead to localized flooding initially, and then depending on how much rain falls a river flooding situation as well.
While convective activity has waned during the evening hours, showers and thunderstorms persist over the Gulf especially in closer proximity to the area of cyclogenesis. Additional showers and thunderstorms will develop overnight offshore, and work their way inland during the early morning hours. In this weather pattern, rainfall is not limited to the afternoon and evening hours. It could rain at any time of the day, and it is very possible that it will be raining around dawn on Friday. For Friday, rainfall will be widespread, but the chances will still be a bit higher from late morning through the afternoon. Sunshine will be very limited the next few days, and with all the moisture and expected rainfall temperatures will be held at bay with lows in the mid 70s and highs only in the low to mid 80s through Sunday. Conditions will likely be slow to improve. The upper level low and the Gulf low will both be slow movers, and rain chances will remain above normal through at least Monday. I still believe its possible that rain chances will max out at 100% this weekend, and decrease some on Monday.
The deep tropical air mass will remain in place even after the lows vacate the area, and the humidity will remain oppressive. With no large scale weather system coming along behind the departing low to scour out the humidity, expect it to remain very humid and warm through mid-week. For the Tuesday and Wednesday periods, a typical late summer day is forecast with sea breeze activity sparking off scattered showers and thunderstorms during the afternoon at the height of daytime heating each day. Temperatures will be seasonable during this time. By the end of the foreacst period on Thursday, some changes for the better should be in the offing. A cold front will be approaching the area, and while there is still some question as to whether or not it will push through and give us a taste of fall, drier air should filter into the region producing lower humidity values and somewhat cooler mornings because of the drier air. Rain chances will also be removed from the forecast at this time. Stay tuned for further revisions to the forecast over the next couple of days.
Tropics: Hurricane Fred is in a weakening state in the Far Eastern Atlantic as it feels the effect of SWly wind shear. Fred has weakened to a category 1 storm tonight. Fred is also moving into an area where sea surface temperatures are only marginal to support intensification. Fred has not only weakened today, but has also decreased in forward speed due to collapsing steering currents. This will likely continue into the weekend with Fred expected to only nudge slowly to the NNE as Fred comes under the influence of a trough to its North. A weakening trend will continue, and Fred will likely be a tropical storm again on Friday. Further weakening will occur over the weekend, and Fred will be a remnant low by the end of the 5 day forecast period, and at this time will likely turn more to the WNW again and accelerate in forward speed as new steering currents around the Atlantic ridge are established.
Hurricane Fred 10p.m. Thursday, September 10, 2009
Latitude: 17.4N
Longitude: 35.1W
This is about 740 miles West of the Cape Verde Islands.
Winds: 85 mph w/ higher gusts---Category 1. Further weakening is expected and Fred should become a tropical storm on Friday. Hurricane force winds extend outward to 30 miles from the center while tropical storm force extend outward to 115 miles from the center.
Motion: North @ 3 mph. Fred is forecast to drift to the NNE through Saturday.
Pressure: 28.94" or 980 mb.
Elsewhere in the tropics...An area of widespread showers and thunderstorms over the NW Gulf of Mexico is associated with a surface trough interacting with a mid to upper-level low. Conditions in this area are only slightly conducive to development due to upper level winds, but this area will have a chance to slowly develop into a weak tropical low over the next couple of days. It will move very little over the next couple of days and hover near the Texas coast. Regardless of development, heavy rainfall is expected along the Gulf coast from Mexico to Louisiana through the weekend.
That's all for a look at the tropics tonight.
Preliminary Numbers & Zone Forecast:
LCH 74/82 75/82 75/83 30 90 60 90 60 80
LFT 73/83 74/83 74/84 30 90 60 90 60 80
BPT 75/82 75/83 76/85 30 90 60 90 60 80
AEX 71/84 73/84 73/87 20 80 50 90 50 80
POE 71/84 73/84 73/86 20 80 50 90 50 80
ARA 75/82 76/82 76/83 30 90 60 90 60 80
Tonight...Mostly Cloudy with a 30% chance of showers and thunderstorms. More likely towards morning. Low 74. SE wind 5-10 mph.
Friday...Cloudy with showers and thunderstorms likely. Heavy rainfall at times. High 82. SE wind 10-15 mph. Chance of rain 90%.
Friday Night...Cloudy with showers and thunderstomrs likely. Locally heavy rainfall at times. Low 75.SE wind 10 mph.
Saturday...Cloudy with showers and thunderstorms likely. Locally heavy rainfall at times. High 82. SE wind 15-20 mph and gusty.
Saturday Night...Rain Continuing. Heavy at times. Low 75. SE wind 10-15 mph. Chance of rain 60%.
Sunday...Cloudy with showers and thunderstorms likely once again. Heavy rainfall at times. High 83. SE wind 10-15 mph. Chance of rain 80%.
7 Day Outlook for Lake Charles & Vicinity
Friday
9-11-09
8 Year Anniversary of the 9/11 Terrorist Attacks
74/82/90
Wind: SE 10-15
H.I.: 87-92
U.V.: 7- Medium
Saturday
9-12-09
75/82/90
Wind: SE 15-20
H.I.: 87-92
U.V.: 7- Medium
Sunday
9-13-09
1 Year Anniversary of Hurricane Ike & 2 Year Anniversary of Hurricane Humberto
75/83/80
Wind: SE 10-15
H.I.: 88-93
U.V.: 8- High
Monday
9-14-09
75/87/60
Wind: SE 10-15
H.I.: 90-95
U.V.: 9- High
Tuesday
9-15-09
74/90/30
Wind: SE 10-15
H.I.: 95-100
U.V.: 10- High
Wednesday
9-16-09
72/90/20
Wind: SW 10-15
H.I.: 95-100
U.V.: 11- Very High
Thursday
9-17-09
68/91/0
Wind: NW 10-15
H.I.: 88-93
U.V.: 11- Very High
...Marine Forecast....
Tonight...East winds 10-15 knots. Seas 1-2 feet.
Numerous showers and thunderstorms.
Friday...Southeast winds 10-15 knots. Seas 1-3 feet.
Rain likely and scattered thunderstorms.
Friday Night...Southeast winds 10-15 knots. Seas 1-3 feet.
Showers and thunderstorms likely.
Saturday...South winds 10- 15 knots. Seas 1-4 feet.
Showers and thunderstorms.
Saturday Night...Southwest winds 10-15 knots. Seas 2-4 feet.
Showers and thunderstorms.
Sunday...Southwest winds 10-15 knots. Seas 1-3 feet.
Showers and thunderstorms.
Friday Tides:
Low: 3:25p.m.
High: 4:01a.m.
Climate Data for Lake Charles...
Thursday, September 9, 2009
Low: 73
Normal Low: 71
Record Low: 61-1943
High: 88
Normal High: 89
Record High: 101-1912
Precipitation:
Rain Today: 0.05"
Month to Date: 1.13"
Normal Month to Date: 2.02"
Year to Date: 42.85"
Normal Year to Date: 40.11"
Sunrise Friday: 6:55a.m.
Sunset Friday: 7:23p.m.
Good night and God bless!!!
-DM-
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