Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Birmingham Alabama
1105 am CDT Friday Aug 22 2014
Middle level ridge was centered just west of the area this morning. A
slight enhancement of the mean moisture will rotate north to south
over central Alabama this afternoon. This will put the best rain chances in
a band from southwest to northeast over south central Alabama.
This was already depicted well in the forecast and no change
warranted. Did make minor adjustments to the temperature trend as things
were heating up quickly this morning. Adjusted dew points
too...and this made the heat indices rise a degree or so
south...and still remains in the advisory range.
12z taf discussion.
Only some isolated MVFR fog this morning...which should be gone
shortly with the sun rising and mixing. Otherwise...expecting hot
temperatures and VFR conditions. Will forgo the mention of thunderstorms and rain for now
as chances will be low.
/issued 519 am CDT Friday Aug 22 2014/
We've been able to escape temperatures near the century mark for the
most part this Summer...but those trends have officially ended. With
the upper ridge now entrenched and 1000-850mb thicknesses continuing
to rise...we should see at least scattered reports of 100 degrees
over the next few days. The big question will be if our climate
sites are able to reach 100...as was stated yesterday have a long
streak on the line of less than 100 degrees. Montgomery will have
the best chance both today and on Saturday. The heat advisory
remains in effect for all of central Alabama through 9pm Saturday
evening. Folks should take the proper precautions to protect
themselves from heat related illnesses. Heat index values will range
from just over 100 degrees in the northern counties...to as high as
108 degrees in the southern counties.
So the heat isn't in question when it comes to the forecast over the
next few days...but the chance of convective development in the
afternoon could be challenging. Looking back at the radar
yesterday...there was a higher amount of convection developing
despite the rising upper heights due to weakly capped
soundings...low-level moisture...and plenty of heat for rising
parcels. The convection was isolated to scattered but still higher
coverage than was forecast. We'll see a very similar situation
today...with convection developing along the periphery of the upper
ridge centered just to our west. Once any storms initiate they will
cause outflow boundary interactions that will keep a few storms
going through the evening hours. Currently...the best chance of
scattered storms will be generally from Demopolis...to Clanton...to
Wedowee and points southward. However...an isolated storm can't be
ruled out across all of central Alabama. Chances will be much lower
west and northwest closer to the upper ridge.
Low level thicknesses increase just a bit once again on Saturday
afternoon...which will be the warmest afternoon for everyone. We
could see quite a few locations reaching the 100 degree mark.
Convective development should be reduced down to a minimum.
Still...have included an isolated chance of a storm or two across
much of central Alabama. We'll re-evaluate those chances on the
Saturday morning package from the latest high-res model guidance and
sounding data...as low-level moisture will remain relatively high.
Heat index values will range from the low 100s north to as high as
109 degrees in the far southern counties.
Sunday will be a sort of transition day...as a relatively cooler
easterly flow will work into central Alabama. The easterly flow
might not reach our western counties soon enough to prevent upper
90s to close to 100 degrees for highs...and we've decided to extend
the heat advisory for locations generally along and west of a line
from Double Springs...to Centreville...to Montgomery through 9pm
Sunday evening. Locations east will see rain chances go up as upper
level impulses move in from the northeast around the retrograding
Fortunately...the above normal temperatures shouldn't last into next
week as the easterly flow continues on Monday and Tuesday. Near
climatology temperatures are expected both days with scattered showers and storms
possible each afternoon. Will forecast upper level ridging
continuing late next week which will keep central Alabama near or
just above climatology on temperatures. No big weather impacts are expected for
much of the southeast through the end of the forecast period with
near zonal flow at 500mb across the eastern Continental U.S..
Preliminary point temps/pops...
Gadsden 96 72 98 73 93 / 20 10 10 10 30
Anniston 97 73 98 74 94 / 20 10 10 10 30
Birmingham 98 75 98 75 96 / 20 10 10 10 20
Tuscaloosa 99 73 99 73 99 / 10 10 10 10 20
Calera 97 74 99 75 96 / 20 10 10 10 20
Auburn 94 74 98 75 94 / 30 20 10 10 50
Montgomery 99 75 100 75 98 / 30 20 10 10 30
Troy 97 73 99 74 96 / 20 10 10 10 40
heat advisory until 9 PM CDT Sunday for the following counties:
Heat advisory until 9 PM CDT Saturday for the following