SW Louisiana Forecast Discussion...The expected afternoon convection never really materialized today with isolated cells at best. The likely culprit was dry air in place after yesterday's activity in association with the departing Upper Level Low. This cutoff ULL was in our general vicinity last night, and moved ESE tonight and is currently centered over the coastal waters of SE Louisiana near the Mouth of the Mississippi River. The movement of the ULL also kept us on its dry side today, increasing subsidence across the forecast area. The air was still relatively dry at the surface as well this afternoon with humidity readings in the 40-50% range once again. With just a few isolated showers and thunderstorms across the forecast area, it was an average day temperature wise with maximums in the lower 90s.
The drier air will remain in place tonight into Friday. Generally, quiet but humid conditions are in the offing tonight with low temperatures in the 68-73 range. The drier air will be replaced on Friday by moist air moving from W to E across the area out ahead of another late August deep trough. Rain chances will be present during the afternoon hours, but initiation may begin later than usual due to increase subsidence early on. The advancing trough will drive another rare August cool front towards the area. The approaching weather feature will give the ULL the boot overnight. This front is currently en route tonight, and is located from West Texas to the Mid West. The best dynamics to support advancement of the front will slide from W to E across the country to our North, so the tail end of this front will slow to a crawl overnight into Friday. This is typical for a front this far South in the Summer. However, the front will eventually move through our area over the weekend as it gets additional support later on. The front will be close enough by late in the day Friday to increase rain chances to just above normal. All in all, it will be a typical late August day with temperatures into the low 90s again with Partly Cloudy skies for much of the day.
The best rain chances this forecast period come on Saturday as the frontal boundary labors its way into and through the area. Shower and thunderstorm activity will not necessarily be limited to the afternoon hours on Saturday, but this time frame will be the most likely time to see some convective activity. I will advertise higher than average rain chances with more than half the area likely seeing some rainfall during the course of the day. It won't be an all day rain event by any means. Temperatures will be around 90 once again. The second half of the weekend will offer much better weather as drier air trickles in behind the front beginning late Saturday, and becoming more pronounced on Sunday as the front penetrates further into the Gulf. I can't rule out a few showers or thunderstorms Sunday especially near the coast as the front struggles to clear the area, but rain chances will be much lower for the second half of the weekend. Temperatures will be a tad cooler Sunday with Partly Cloudy skies, but just wait...
Drier and even some cooler air filters into the forecast area to close out August on Monday. This will persist for the remainder of the forecast area with high pressure dominating. Rain chances will be absent from the forecast during this time, and the humidity will be quite bearable once again. The coolest air arrives at mid-week as the Canadian high in the wake of the front positions itself closer to our area providing fresh Northerly breezes. Low temperatures are expected to fall into the low to mid 60s at this time, with some of the coolest locations in Northern portions of the forecast area possibly reaching the upper 50s. This will be the coolest temperatures we've seen since May. Afternoon maximums will be warm, and a large daily diurnal range is expected since it will be early September. High temperatures for days 5 through 7 will be in the 85 to 90 degree range, with the humidity the most noticeable difference. It should be a string of refreshing days, and a nice reminder to us that fall ins't too far away now.
Tropics:
The tropics remain active. Tropical Storm Danny is hanging on for survival tonight, and in all honesty it looks more like a Subtropical system. Danny is very disorganized with its low-level center still exposed to the left of all the convection. The strongest winds are displaced well to the NE of the center of circulation. Hurricane Hunters continue to investigate the system tonight. Danny is feeling the effects of the Gulf coast Upper Level Low, and as a result of this strong SSWly shear is present at this time. The storm should continue to struggle into the day on Friday, before conditions become a bit better to support development. The period of favorable conditions for intensification is forecast to be brief at this point as the trough advances towards the East coast. At this time, Danny is expected to remain a Tropical Storm with a similar forecast track to my discussion from last night with a track near the Outer Banks of North Carolina Saturday. The storm has not moved much today, but a slow N to NW drift has been noted tonight. T.S. Danny should generally move Northward on Friday, and it will increase in forward speed over the next couple of days as it feels the effects of the trough. The storm will parallel the East coast, and could come very close to Long Island or Cape Cod over the weekend as it transitions into an extratropical entity. Based on the current forecast track, a Tropical Storm Watch is in effect for the coast of North Carolina from Duck to Cape Lookout. Additional watches and/or warnings are possible for portions of the East coast on Friday especially if the forecast track shifts further West.
Here is the 10p.m. Advisory on Tropical Storm Danny:
Tropical Storm Danny 10p.m.- Thursday, August 27, 2009
28.4N
73.5W
This is about 485 miles SSE of Cape Hatteras, NC.
Maximum Sustained Winds: 45 mph w/ higher gusts---some strengthening is possible through Friday. Tropical Storm force winds extend outward to 205 miles mainly to the NE of the center.
Movement: NNW @ 8 mph---A general motion towards the North, and an increase in forward speed is expected Friday.
Pressure: 29.77" or 1,008 mb.
Large swells and dangerous rip currents will affect the East Coast through the weekend.
Danny is currently the only active named storm out there, but it looks more and more likely tonight like we will have another one by this weekend. It is the vigorous tropical wave that I talked about last time. It emerged off the coast of Africa earlier this week. It is currently located about 450 miles SW of the Cape Verde Islands in the Far Eastern Atlantic. It is moving off to the West at 15-20 mph, and this will likely continue through Saturday. Further development of this system is expected over the next few days, and I expect this system to become Erika in the coming days. Forecast models have been initiated on this system, and I will display those in just a moment. It is far too early to predict where this system is going, but it will be the system to watch next week.
Elsewhere, no tropical storm formation is expected through Saturday.
Preliminary Numbers & Zone Forecasts:
LCH 71/89 71/90 70/89 10 40 20 60 30 30
LFT 69/88 70/90 71/90 10 40 20 60 30 30
BPT 73/88 72/89 69/90 10 40 30 50 30 20
AEX 67/90 69/88 66/89 10 50 40 30 20 10
POE 68/89 69/88 67/89 10 50 40 30 20 10
ARA 70/88 72/90 71/90 10 40 30 60 30 30
Tonight....Mostly Clear to Partly Cloudy. Low 71. Light SE wind.
Friday...Partly to Mostly Cloudy with a 40% chance of showers and thunderstorms mainly late in the day. High 89. SE wind 10-15 mph.
Friday Night...Partly Cloudy with a 20% chance of showers and thunderstorms. Low 71. SE wind 10 mph.
Saturday...Partly to Mostly Cloudy with a good chance of showers and thunderstorms. High 90. SE to SW wind 10-15 mph.
Saturday Night...Mostly Cloudy with a 30% chance of showers and thunderstorms. Low 70. SW wind becoming NW at 10-15 mph.
Sunday...Partly Cloudy with a 30% chance of showers and thunderstorms mainly in the morning. High 89. NW wind 10-15 mph.
7 Day Outlook for Lake Charles & Vicinity
8-28-09
Friday
71/89/40
Wind: SE 10-15
H.I.: 95-100
U.V.: 10- High
Saturday
8-29-09
4 Year Anniversary of Hurricane Katrina
71/90/60
Wind: SE/SW 10-15
H.I.: 93-98
U.V.: 9- High
Sunday
8-30-09
70/89/30
Wind: NW 10-15
H.I.: 88-94
U.V.: 11- Very High
Monday
8-31-09
67/88/0
Wind: NW 10-15
H.I.: 85-90
U.V.: 11- Very High
Tuesday
9-1-09
1 Year Anniversary of Hurricane Gustav
65/86/0
Wind: North 5-10
H.I.: 85-90
U.V.: 11- Very High
Wednesday
9-2-09
63/88/o
Wind: NW/SW 10
H.I.: 85-90
U.V.: 11- Very High
Thursday
9-3-09
66/90/0
Wind: SW 10
H.I.: 88-93
U.V.: 11- Very High
Marine Forecast from NWS Lake Charles
Tonight...S-SW winds 5-10 knots. Seas 1 foot. A slight chance of showers
and thunderstorms.
Friday...Southwest winds around 5 knots. Seas 1 foot.
A chance of showers and thunderstorms.
Friday Night...Southwest winds 5-10 knots. Seas 1 foot.
A chance of showers and thunderstorms.
Saturday...W-SW winds 5-10 knots. Seas 1-2 feet in the afternoon.
A chance of showers and thunderstorms.
Saturday Night...SW-W winds 5-10 knots. Seas 1-2 feet.
A slight chance of showers and thunderstorms.
Sunday...Southeast winds 5-10 knots. Seas 1-2 feet.
A slight chance of showers and thunderstorms.
Friday Tides:
High: 2:22a.m.
Low: 5:53p.m.
Climate Data- Courtesy of NWS Lake Charles
Thursday, August 28, 2009
Low: 71 Normal Low: 73 Record Low: 64- 1968
High: 92 Normal High: 91 Record High: 101- 1913
Precipitation:
Rain Today: 0.00"
Month to Date: 4.95" Normal Month to Date: 4.12"
Year to Date: 38.66" Normal Year to Date: 37.36"
Sunrise Friday: 6:48a.m.
Sunset Friday: 7:40p.m.
Good Night and God bless all!!!
-DM-
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