Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Birmingham Alabama
356 am CDT sun Jul 31 2016


Alabama is currently located at the very edge of the base of an
upper-level trough which is moving slowly across the Ohio Valley and
Great Lakes. Weakly cyclonic curvature is evident in the 500mb flow
which is generally favorable for summertime afternoon showers and
storms. Also a remnant mesoscale convective vortex is drifting eastward from MS and could be
somewhat of a focus for convective development later today, though
the hrrr has very little development through 21z. However, this
seems a bit underdone given the 70s dewpoints in place across the
region and the aforementioned factors. Scattered showers and storms
are expected with 30-40 pops mainly during the afternoon.


Monday through Sunday...we start the period with a wave moving through
the upper levels. Cyclonic flow was exhibited by models from at
least 850mb to near 500mb. Precipitable water values will be 1.80
inches or higher with mean relative humidities values of 70
percent. Therefore, increased rain chances on Monday with the
highest values in the south. Will have to monitor these
developments as it is possible the rain chances may need to be
increased farther northward and earlier in the day depending on
the timing.

After this wave, central Alabama becomes under more northerly flow
aloft as a main weakness in the ridge slides eastward and a ridge
builds over the plains. This ridge will oscillate and build around
the mid section of the conus until another wave moves through the
westerlies next weekend. Additionally, a low is progged to move
into the Bay of Campeche area at this time also.

So overall, models are in relatively good agreement and also
agree with the ongoing forecast. Although it appears moisture
values drop or at least move up and down periodically, highs in
the low to mid 90s and scattered thunderstorms (climatology) remain
each day. Boundary layer guidance these days suggest some hefty
mixing but am not inclined to bite on this just yet. This would
drop heat indices and potential give US some stronger storms. Will
keep mention of heat indices 100 to 105 degrees. Isolated storms
may produce wind gusts 30 to 40 mph and heavy downpours due to
light mean winds.



06z taf discussion.

VFR conditions are prevailing this evening for all terminals, and
should continue for a majority of the night. Patchy fog will be
possible around terminals that received rainfall, such as keet,
but confidence remains low of any major vis restriction below
MVFR. Surface winds will be calm or light and variable through the
night, with light westerly winds expected during the afternoon
hours on Sunday. Thunderstorms in the vicinity remains in all tafs with scattered showers
and storms expected to develop once again Sunday afternoon.



Fire weather...

Generally scattered showers and thunderstorms are expected over
the next several days with highs low/mid 90s. Surface winds will
be less than 10 mph and generally from the southwest/west through
the first of the week. Since surface dew points are so high,
critical fire weather thresholds are not expected to be met, with
no watches or warnings anticipated.


Preliminary point temps/pops...
Gadsden 92 72 92 71 93 / 30 30 50 40 30
Anniston 92 73 92 71 93 / 30 30 50 40 30
Birmingham 93 75 92 73 92 / 30 30 50 40 30
Tuscaloosa 94 74 93 74 94 / 30 30 50 40 40
Calera 93 74 93 73 93 / 30 30 50 40 40
Auburn 93 74 91 73 93 / 30 30 60 40 40
Montgomery 96 75 94 74 94 / 30 30 60 40 40
Troy 94 73 94 72 92 / 30 30 60 40 40


Bmx watches/warnings/advisories...



National Weather Service Glossary of Abbreviations