Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Birmingham Alabama
646 am CDT Thursday Aug 21 2014
for 12z aviation.
The radar is all clear early this morning after a fairly eventful
evening yesterday across our eastern counties. The radar should stay
fairly quiet today as the upper ridge really starts to take
control. On the periphery of the ridge we could see a few isolated
storms develop during the peak heating of the day across our
eastern counties. Otherwise...rising upper heights should limit
convective development. If any isolated storm develops...it could
pack a punch with gusty winds due to dry air still existing aloft.
However...since coverage is expected to be so low today...will not
highlight any isolated severe threat in the severe weather potential statement at this time.
What will be highlighted in the severe weather potential statement is the building heat today
through the weekend. Although we aren't planning on issuing a heat
advisory for today at this time...1000-850mb thicknesses are
supportive of middle to upper 90s...with a few spots across our
southern counties close to heat advisory criteria. We'll continue
to just highlight today's heat in the severe weather potential statement for now. Friday and
Saturday are the days of most concern for central Alabama...as
temperatures will easily rise into the upper 90s to perhaps 100 degrees
for several locations. Even if we're able to mix dew points into
the middle 60s which would lower the heat index below 105
degrees...we still could reach 99 to 100 degrees in terms of the
actual temperature. Therefore...even though some locations might
not reach heat advisory criteria we're going to go ahead and issue
a heat advisory. The advisory will be for all of central Alabama
starting at 11am Friday morning and lasting through 9pm Saturday.
Temperatures are going to be the hottest that we've seen so far
this Summer...and with lots of outdoor activities going on this
weekend we wanted folks to make sure to plan accordingly and take
the proper precautions. We'll see if we break the streak of
consecutive days below 100 degrees...which is 780 days for
Birmingham and 751 days for Montgomery.
After another very hot day on Saturday...the upper ridge looks to
weaken just a bit with northerly flow aloft by Sunday. At the
surface...easterly flow will move into the state by the afternoon
hours with a weak surface low expected to move westward along the
Gulf Coast. The increase in moisture along with upper level impulses
moving southward around the upper ridge will increase rain
chances across eastern Alabama...and lower high temperatures.
Western Alabama will still be very hot...and we may need to
consider a heat advisory at least for counties west of I-65 over
the next day or so. Easterly flow at the surface will continue
into Monday...with highs dropping close to seasonal levels once
again and a good chance of showers and storms during the
afternoon. The end of the forecast period features near to just
above climatology temperatures with upper ridging remaining in control for much
of the southeast states.
12z taf discussion.
Except for a couple of spots with MVFR fog for an hour or so
possible...VFR conditions are expected across the c Alabama tafs.
Although there is a chance for some isolated heat induced convection
this afternoon across the far eastern sections (ie...anb)
probability is low and not high enough to mention in taf. Even
less chance for fog tonight with even less boundary layer moisture
expected to work with tonight and very low rain chances overall.
Overall...this package light west/northwest winds and fair
weather cumulus/maybe some towering cumulus in the east in the
Preliminary point temps/pops...
Gadsden 95 71 97 72 96 / 20 10 10 10 10
Anniston 96 71 97 73 97 / 20 10 10 10 10
Birmingham 97 74 98 75 98 / 10 10 10 10 10
Tuscaloosa 97 72 99 73 99 / 10 10 10 10 10
Calera 96 73 98 74 98 / 10 10 10 10 10
Auburn 96 73 97 74 96 / 20 10 10 10 10
Montgomery 98 75 99 75 100 / 10 10 10 10 10
Troy 97 72 98 73 98 / 20 10 10 10 10
heat advisory from 11 am Friday to 9 PM CDT Saturday for all of