Thursday Morning Forecast

Forecast Issued by Randy Bowers on 04/19/2006 at 11:48:57 pm CT

Mobile, Alabama 5 Day Forecast
Today	Friday	Saturday	Sunday	Monday
87°F	85°F	84°F	84°F	86°F
	68°F	67°F	56°F	57°F
S 5 mph	SW 5-10 mph	SW 5-10 mph	VAR 5 mph	S 5-10 mph
10%	20%	30%	0%	0%

Detailed Forecast

Today... Areas of fog in the morning. Otherwise, partly cloudy. High 87. Winds south at around 5 mph. Thursday Night... Partly cloudy. Low 68. Winds south at around 5 mph. Friday... Partly cloudy with isolated thunderstorms during the afternoon. High 85. Winds southwest 5-10 mph. Chance of rain is 20 percent. Friday Night... Partly to cloudy with a chance of thunderstorms. Low 67. Winds southwest 5-10 mph. Chance of rain is 30 percent. Saturday... A chance of thunderstorms, mainly in the morning. Otherwise, mostly cloudy early with partial clearing during the afternoon. High 84. Winds southwest 5-10 mph. Chance of rain is 30 percent. Saturday Night... Partly cloudy. Low 56. Winds variable 5 mph. Sunday... Partly cloudy. High 84. Winds variable 5 mph. Sunday Night... Partly cloudy. Low 57. Winds variable 5 mph. Monday... Partly cloudy. High 86. Winds south 5-10 mph.

Technical Discussion

One concern earlier this evening was that activity over central Alabama would be able to generate a substantial enough cold pool, with time, to begin propagating more quickly southward/southeastward. Thus far, this has not happened. The thought was that even if it were to happen, it would propagate with mean flow and remain near parallel to NW-to-SE oriented surface boundary which was located well to our east and thus not being much of a threat to Mobile. Latest trends are for a more westward building of convection behind a westward propagating outflow boundary. Despite stabilizing boundary layer, thunderstorms should continue to develop behind this westward moving outflow boundary through the evening and into the overnight --likely becoming increasingly more elevated in nature. Believe this process will continue long enough for convective cluster to at least reach a Carrollton, to Camden, to Enterprise line. Believe with decrease in instability as a result of nocturnal cooling that westward moving boundary will become less and less effective at convective generation as time goes by. Rather substantial low level temperature inversion has developed along the coast this evening, evident on KMOB 88d with AP returns oriented parallel to the coast. Inversion was not yet evident at 00z on the KLIX sounding and has likely only recently strengthened with nocturnal cooling of the boundary layer now well underway. Fog formation is a concern later tonight with strong inversion coupled with light winds and T/Td spread rather small. Will mention fog for the first part of period one. Forecast for the next few days will weigh heavily on the behavior of diurnal convective development invof boundaries and their effect on said boundaries. Additionally, convectively generated boundaries will also be a factor as sfc/near sfc winds will likely prove insufficient to displace /mix out/ these outflow boundaries. This is very much a summer-like pattern with weak ridging aloft resulting in relatively light winds throughout the column. Unseasonably warm temperatures will continue as well with near record highs once again tomorrow. Will forecast a high one degree below the record which is still slightly above MOS consensus but seems reasonable given ridging aloft and similar thickness and sky cover as today. Only concern with respect to temperatures would be if clouds were a little more prevalent limiting insolation. This seems to be the cause for MOS' somewhat cooler temperatures. For now will forecast partial sky cover and go slightly above MOS for consistency sake, if nothing else. Synoptically, NAM shows a weak perturbation at H5 passes just north of Mobile during peak heating tomorrow. Thinking any convection will be focused just north of the city and will only go with a silent 10 PoP attm. A more substantial wave crosses the area Fri night/Sat. An associated cold front attempts to make it to Mobile and per coordination with pervious shift, models were considerably more aggressive with sfc features in the 12z run. New 00z run seems comparatively aggressive and am apt to buy into this. Regardless, even without full fropa, diurnal convection along and ahead of front would likely be enough to justify the going PoPs in the forecast. In fact, going PoPs may be on the low side but will not alter as of yet given lack of confidence in surface features, timing, and effect of more recent convective activity. Beyond Saturday, surface ridge takes over with a slight releif from heat and humidity. Deep moisture shifts east with progression of mid/upper trough and PWAT values fall substantially despite some lingering low level moisture. Therefore, will leave PoPs out beyond Saturday. 0-6km shear of AOA 30 kts should be enough to favor some storm organization late Fri into early Sat. Additionally, at least marginal lapse rates and weak to moderate instability may favor intense convective updrafts. Isolated severe multi-cells seems possible with trough passage late Fri into Sat, but given pulse-like nature due to vertical/near-vertical updrafts, any severe events will likely be marginal hail or wind, and brief. Will mention this in the HWO product. Generally kept the same theme as going forecast with only a few changes, mainly to PoPs and wording for timing. Also, the introduction of HWO highlighting isolated marginal severe threat Fri-Sat. I stuck close to MOS, though I discounted FWC's low temperature for second period as Tds initialized way to low and remain way to low through the forecast period. For second period temperatures, went with MET.

Hazardous Weather

A weak weather system will pass through the area late Friday into early Saturday. Although some rainfall is expected, this system is not expected to bring widespread relief to the dry conditions as not everyone will see rain. The rain is expected to come in the form of isolated to scattered thunderstorms beginning as early as Friday afternoon and lasting until late Saturday morning. A few of these storms may become rather intense and produce hail and gusty winds. An isolated severe thunderstorm with large hail and damaging winds cannot be ruled out. Although the severe weather threat is not particularly high, persons in the Mobile area are encouraged to remain alert and monitor the weather conditions between now and Saturday. You should be ready to take action in order protect life and property should severe weather threaten your area.

Astronomical and Climatological Data
Moon Phase Half Full (Waning) Sunrise 6:20 AM Sunset 7:24 PM	04/20/06 Normal High Record High Normal Low Record Low Temperature 78°F 88°F (1968) 56°F 40°F (1953) April Normal Wettest Driest Precipitation 5.06 in. 17.69 in. (1955) 0.08 in. (1999)