Storms Firing Up…

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A quick check shows the current dewpoint in Birmingham at 71, and the precipitable water from the 12Z sounding was 2.08″… all of that means a very moist airmass remains in place, with with little in the way of a capping inversion look for scattered to numerous showers and thunderstorms this afternoon into the nighttime hours. You know the deal; the stronger storms will produce very heavy amounts of rain due to their slow forward motion, lots of lightning, and in some cases the potential for wet microbursts.

LOOKING AHEAD: No real change in our weather tomorrow; a good chance of showers and storms during the afternoon and evening hours with a high in the 86 to 90 degree range. Some model madness begins on Friday; the GFS hints at drier air moving in here from the north, but the NAM keeps the air very moist and juicy. I think in this case the NAM is the correct model; the leading edge of the drier air north of Alabama should hang up somewhere near the Tennessee Valley. So, scattered showers and storms remain possible on Friday.

FRIDAY NIGHT LIGHTS: For the first big night of the high school football season, there will be scattered thunderstorms around here Friday evening, but they will diminish by 8:00 to 10:00. Some games might be delayed where lightning is an issue. The kickoff temperature should be around 85 degrees, but expect upper 70s where showers form.

COLLEGE GAME DAY: Both Alabama and Auburn are playing home games Saturday evening. Pretty much the same situation at both Tuscaloosa and Auburn; a thunderstorm is possible mainly during the first half. The kickoff temperature will be in the mid to upper 80s.

LABOR DAY WEEKEND: I really don’t think the air over Alabama will dry very much, so on all three days we will have the risk of scattered, mainly afternoon and evening showers and thunderstorms. Afternoon highs will be close to 90 degrees. There will be some good intervals of sunshine also during the midday hours.

TROPICS: Beginning to heat up……

*A disturbance east of Charleston has the potential to become a tropical depression during the next 24 hours. This will drift southward, and with little in the way of steering currents, this thing will probably meander around, just off the South Atlantic coast of the U.S., for the next four to five days. One model, the Florida State MM5, brings it to the Atlantic coast of Florida, a little south of Cape Canaveral, in 72 hours. But, most of the models keep it over the open water through Saturday.

*The wave about 800 miles east of the Windward Islands has the potential to become a tropical depression during the next 48 hours. Most of the models keep this one moving west/northwest, through the Caribbean over the weekend. It will encounter increasingly warmer SSTs on the journey, so it will be one to watch.

*A tropical storm is forming in the Pacific, south of Baja California. This system will be forced northward, and could make landfall on the southern tip of Baja, or somewhere on the main Mexican coast, over the weekend as a significant hurricane. This batch of moisture is then headed for the Southwest U.S., where some flooding might become a problem early next week.

FYI… the next named storms in the Atlantic basin will be Felix, Gabrielle, and Humberto. “We don’t name em, we just forecast them.”

LONG RANGE: The 12Z GFS does show two really nice shots of cool, Canadian air moving southward into the U.S. in the medium range period (September 8-15), but both seem to run out of gas before reaching Alabama. Our time will come, but we might have to wait until the latter half September before we get down into the 40s and 50s.

BIRMINGHAM NEWS FRONT PAGE: I have several e-mail messages from people wanting to know my opinion on the article on the front page of the Birmingham News this morning about the possibility of an extended drought due to La Nina conditions. Here is the response I wrote one reader:

“That makes a good headline, but there is inherent danger in any seasonal forecast… so I would take it with a “grain of salt”.

I think the bigger issue is that we are in a warm AMO phase now (Atlantic Multidecadal Oscillation), which is the reason for the warmer global temperatures in the last decade and increased tropical activity. That in itself would suggest warmer than normal temps for much of the nation through 2008, with a sharp cool down in the following years.

But again, not much skill in being too specific here.”

I do think there is a very real chance Alabama will be impacted by one or more tropical systems during the next two months, and that will sure be a nice short term drought-buster.

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