Wednesday Night Forecast

Forecast issued by Randy Bowers on 10/18/06 at 5:17:10 pm CDT

Mobile, Alabama 5 Day Forecast
Tonight	Tomorrow	Friday	Saturday	Sunday
	84°F	73°F	79°F	79°F
71°F		63°F	54°F	65°F
SE 4-8 mph	SW 5-10 mph	NW 5-10 mph	NE 4-8 mph	S 5-10 mph
40%	60%	0%	20%	30%

Mobile, Alabama 5 Day Detailed Forecast

Tonight… Mostly cloudy with scattered showers and thunderstorms. Low 71. Winds southeast 4-8 mph. Chance of rain is 40 percent. Tomorrow... Mostly cloudy with rain and thunderstorms. High 84. Winds southwest 5-10 mph. Chance of rain is 60 percent. Thursday Night... Mostly cloudy with scattered showers and thunderstorms in the evening. Then, decreasing cloudiness after midnight. Low 63. Winds west 5-10 mph. Chance of rain is 50 percent. Friday... Partly cloudy. High 73. Winds northwest 5-10 mph. Friday Night... Partly cloudy. Low 54. Winds north 4-8 mph. Saturday... Partly cloudy with isolated showers. High 79. Winds northeast 4-8 mph. Chance of rain is 20 percent. Saturday Night... Mostly cloudy with scattered showers and thunderstorms. Low 65. Winds east 4-8 mph. Chance of rain is 30 percent. Sunday... Mostly cloudy with scattered showers and thunderstorms. High 79. Winds south 5-10 mph. Chance of rain is 30 percent. Sunday Night... Mostly cloudy with scattered showers and thunderstorms. Low 57. Winds west 5-10 mph. Chance of rain is 30 percent.

Technical Discussion

Synopsis: Surface analysis indicates somewhat diffuse sfc boundary lifting northward across the region this afternoon. Sfc winds expected to veer to the south/southeast this evening/early tonight before further veering toward morning. SWrly, sfc flow will be dominate across the region tomorrow. In the mean time, WAA regime resulting in ongoing SHRA/TSRA just off-shore and further west across Louisiana. This activity seems to be focused along theta-e gradient which will continue to move Nwrd into the area overnight. Have placed a 40 PoP in overnight to account for this. Forecast concerns center around shortwave now seen in WV over Rocky Mountain region. Models are similar with timing/intensity with Ewrd progression, though NAM is the strongest/slowest. GFS doesn't lag by much but is a little quicker, showing a fropa at or just after 00z. NAM, on the other hand, shows a little slower fropa, around or just before 06z. NGM sides with the NAM showing a slower fropa. Given this, am inclined to go with the NAM/NGM timing. However, previous forecaster suggested that GFS had a better handle overall as it initialized better. Will therefore split the difference in NAM and GFS with regard to timing. Different setup than last so expect convective mode to be different. Last system brought convective showers which brought a tornado/enhanced wind threat given high-shear/low CAPE environment. Models indicate LLJ/H8-H9 winds to be about half as intense as with previous system--indicating roughly 30-40 kt LLJ tomorrow afternoon. Result is less ovrall shear, both directional and speed, with 0-6km speed shear certainly still favorable for organized convection. With that said, instability appears to be higher with this system per guidance--although still rather weak given poor mid-level lapse rates. All things considered, a severe threat will exist tomorrow afternoon/early tomorrow night, though with best mid-upper dynamics lagging behind sfc boundary, feel that severe threat will be marginal and limited to multi-cell and bow structures with primary threat of damaging winds. Adequate shear for mid-level rotation may enhance hail threat somewhat, especially in the most robust updrafts. Post-fropa air mass much drier and cooler. Generally followed MOS for temperatures Fri-Sat. During that time, boundary becomes parallel to mean flow and stalls just off the coast. NAM and GFS both indicate a wave developing along this boundary and WAA regime expected again by late Saturday. For now, have add a small PoP Saturday to cover timing uncertainties. GFS is more aggressive with mstr return than NAM--showing QPF by late Saturday which NAM holds it off at least another 12 hours.

Hazardous Weather

Short Term (Today through Thursday) The probability for thunderstorms will increase overnight tonight and especially tomorrow. The best chance of thunderstorms will come late tomorrow afternoon as a cold front approaches. Although widespread significant severe weather is not anticipated, a few marginally severe thunderstorms are possible. Damaging winds will be the primary severe weather threat. Long Term (Friday through Sunday): No hazardous weather is expected at this time.

Astronomical and Climatological Data
Moon Phase Crescent Waning Sunset 6:17 PM Sunrise 6:57 AM	10/18/06 Normal High Record High Normal Low Record Low Temperature 79°F 89°F (1972) 55°F 35°F (1948) October Normal Wettest Driest Precipitation 3.25 in. 13.20 in. (1985) 0.00 in. (1874)