Tuesday Morning Forecast

Forecast issued by Justin Gibbs on 08/29/06 at 1:05:27 am CDT

Mobile, Alabama 5 Day Forecast
Today	Wednesday	Thursday	Friday	Saturday
91°F	88°F	89°F	90°F	91°F
	74°F	72°F	72°F	74°F
Var 5-10 mph	Var 5-10 mph	Var 5-10 mph	Var 5-10 mph	Var 5-10 mph
30%	40%	20%	20%	20%

Mobile, Alabama 5 Day Detailed Forecast

Today... Partly cloudy with scattered showers and thunderstorms. High 91. Winds variable 5-10 mph. Chance of rain is 30 percent. Tonight... Variable cloudiness with scattered showers and thunderstorms. Low 74. Winds west 5-10 mph. Chance of rain is 40 percent. Wednesday... Partly cloudy with scattered showers and thunderstorms. High 88. Winds variable 5-10 mph. Chance of rain is 40 percent. Wednesday Night... Mostly clear with isolated showers. Low 72. Winds variable 2-4 mph. Chance of rain is 20 percent. Thursday... Partly cloudy with isolated showers and thunderstorms. High 89. Winds variable 5-10 mph. Chance of rain is 20 percent. Thursday Night... Mostly clear. Low 72. Winds variable 5-10 mph. Friday... Partly cloudy with isolated showers and thunderstorms. High 90. Winds variable 5-10 mph. Chance of rain is 20 percent. Friday Night... Mostly clear. Low 74. Winds variable 5-10 mph. Saturday... Partly cloudy with isolated showers and thunderstorms. High 91. Winds variable 5-10 mph. Chance of rain is 20 percent.

Technical Discussion

Synopsis: Very light sfc flow exists across the region this morning. Sfc analysis indicates cold front draped from KPOF to KTKX to just west of KSHV at 05z. Aloft WV/RAOB indicates light ridging persists to our east while an unseasonably strong s/wv trof is evident throughout much of the column with the trof axis aross WRN KS and the TX/OK Panhandle. 12z KLIX/KTLH soundings show a fairly seasonable tropical airmass in place with just a touch of drier air working in around 500mb as it rides around the WRN periphery of the afforementioned UL ridge. Forecast Discussion (Tuesday through Saturday): Short Term... Tuesday through Wednesday evening prove to be the main focus of this forecast package. Main forecast concerns revolve around timing of sfc frontal boundary and the coverage of SHRA/TSRA as the system moves through. GFS/NAM/UKMET/ECMWF all are in acceptable agreement this morning on a ~6z Wednesday FROPA, which appears rather reasonable given the strength of the UL s/wv pushing the main cyclone. Upper air modeling however does show the wind fields aloft weakening through the first 24-36 hours and vort maps at 500mb show a rather substantial decrease in PVA as the s/wv moves across KY/TN and drapes further southwest. This however does appear to be a little bit too conservative given the strength and breadth of the system and the lack of any real stopping force as it barrels to the east. Very meager lapse rates have prevented much areal coverage in our convection over the past 48 hours and that will be factored into the coverage pops and the handling of first period. Will stick with the going 30 pops mainly for the afternoon period as the s/wv appraoaches. Despite the strength of the wave will not go above 40 pops for the Tuesday evening period as the most organized and widespread convection will likely be limited to the breif window of improved lapse rates (up from invof 5c attm) as the shortwave nears and passes, which will be well after peak heating (between 6-9z.) 700mb omega charts, and lower level moisture analysis indicates the frontal system will also likely be quite a bit more diffuse the further south you go, leading to the likelihood of increased convection across middle AL while we stay relatively dry. Day shift may need to tweak this however if the model consensus proves to not verify. Wednesday will leave the going 40 pop in to prepare for the possibility of the boundary stalling as it moves east as the GFS appears to suggest. This solution is somewhat discounted but if the system is slower than currently forecast (which has been the trend for the past few days) we could see some AM showers fire once heating begins. Long Term... Once the system clears gudiance points towards a split-flow regime aloft across the ERN CONUS and heights stay relatively low. This solution appears to be a bit unlikely given climo and will assume a slowed weakening shortwave shortly after it punts Ernesto from the ERN coast of Florida. MOS doesn't seem to reflect the slightly lower projected heights, which do appear reasonable, and has been a touch too warm for the past few days. Going MOS -1 to line up with going forecast for the extended period temperaures. Thursday the extended guidance gets a bit murky. ECMWF/GFS stall the s/wv a bit and GFS cuts off another powerful ULL into the central CONUS. This relatively new and climatologically obscene maneuver will be discounted for now and we will lean more towards climo which appears to be working fairly well below 300mb on the GFS run which builds another weak to moderate ridge over the extreme SERN CONUS which should warm us back up and return us to an airmass very similar to what we are in now. Drier air behind the trof will allow us to remove overnight pops for the Thursday night and Friday night period. For now will also go below climo pops and get in line with mos (as current forecast does) keeping a SLGHT CHC dinural pop in each day period as opposed to the 40/50% coverage we were seeing late last week. Ernesto... Latest NHC 5-day continues to indicate Ernesto will remain well east of the area, latest suite of guidance builds forecast in that solution. If the slightly slower trend continues amongst the guidance suite it is possible the storm may move slightly further eastward, however it is still expected the system will remain far enough east to not bring any noticable weather to the Mobile area.

Hazardous Weather

Short Term (Tuesday through Monday): There is a chance of thunderstorms today, tonight, and early Wednesday as a cold front appraoches from the northwest. Coverage of these thunderstorms is currently expected to be rather limited with maximum activity in the overnight and early morning hours Wednesday. Where storms occur expect gusty winds, dangerous lightning, and very heavy rainfall, with rainfall rates up to 3/4 of an inch per hour. Widespread severe weather is not anticipated at this time. Long Term (Tuesday through Saturday): No hazardous weather is expected.

Astronomical and Climatological Data
Moon Phase First Sunrise 6:26 AM Sunset 7:19 PM	08/29/06 Normal High Record High Normal Low Record Low Temperature 90°F 105°F (2000) 71°F 61°F (1992) August Normal Wettest Driest Precipitation 6.20 in. 15.22 in. (1881) 1.04 in. (1997)

08/29 in Mobile Area Weather History

In 2003 a large waterspout formed in Mobile Bay and moved northwest towards downtown Mobile in Mobile County, AL before weakening. Many workers in downtown high rise buildings had an excellent view of the funnel. Also, in 2005 powerful hurricane Katrina made landfall 90 miles west of Mobile on the west Mississippi coastline. Katrina, although a category 3 storm at landfall, produced an enormous storm surge that inundated areas from the southeast coast of Louisiana to downtown Mobile. Its broad circulation allowed hurricane-force winds to extend over 90 miles from the center, impacting portions of Mobile and Baldwin Counties in Alabama. The outer feeder bands produced an F0 tornado near Huxford in Escambia County, AL where it downed trees and power lines. (Data compiled from NWS Mobile, NWS Birmingham, newspaper articles, USA Archives and HurricaneCity.com)