Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Birmingham Alabama
436 am CDT Thursday Apr 2 2015

Discussion...

Will this unsettled pattern ever end. For the short term the
answer is yes...for the longer pattern the answer is no. Hey this
is Spring after all. You remember the saying April showers bring
may Flowers...well just expect a bunch of Flowers in may.

So what is in store? Well today will be a transition day and
primer for the strong cold front that will work into the area on
Friday afternoon and swing through Friday evening. There will be
plenty of activity along the front and will likely result in
strong to severe thunderstorms for the northern half of the
forecast area Friday afternoon into Friday night. Models have been
fairly consistent with an overall timing of 4 PM to midnight for
the greatest concern of severe storms. After midnight the main
dynamics leave the area and the activity will begin to dwindle
down as the front moves into the southeastern portions of the
area. Storm Prediction Center has placed the northwestern 5 counties into the enhanced
risk with a 30 percent chance at seeing severe weather...meanwhile
the areas generally along and north of the I-20 corridor is in the
slight risk. Areas along and south of the I-85 is just in the
general thunderstorms expectation. Looking at just a few NAM
forecasted severe parameters to increase or decrease my confidence
on the threat levels. Right at 00z Friday night/Saturday...cape
values of 1000 to 1500 j/kg...lifted indices of -4 to -5...dewpoint in the
middle 60s...increasing low and middle- level lapse rates...the best
0-1km helicity remains to our north and exits northeast as the
front pushes through. With what has been advertised by the
models and overall synoptic setup...have no qualms about the
overall placement of the slight and enhanced risks by Storm Prediction Center at this
time.

Most of the stronger activity will be ending by midnight across
the east and the front will continue to slide south. Most of the
rain will out by Saturday morning and dry weather will be in place
for most of Saturday and Sunday along with cooler temperatures.

As we work into next week...another baroclinic low will develop
and slide along the previous cold front and move into the area
late Sunday night into Monday morning as the southern stream of
the jet remains active. This southern stream will remain active
through the week with scattered showers and storms each day
through next Thursday. Another strong cold front by Friday but
more on that in the upcoming days.

16

&&

Aviation...
06z taf discussion.

No showers or thunderstorms currently in central Alabama. With
several boundaries moving through the area...can not rule out an
isolated shower or storm overnight...but confidence and rain chances
at any one terminal are too low to include at this time.

Surface moisture remains high overnight...and a period of reduced
visible and low ceilings is possible later tonight and near sunrise. Given
the lack of rainfall today...do not expect conditions below MVFR.
Looking at near term model guidance...low stratus deck attempts to
build into central Alabama early Thursday morning from east while
fog spreading northward from the Gulf reaches far south central
Alabama. Not confident in either of these solutions as there is not
any current visible reductions to our south...and the stratus deck to
the east is near the Atlantic coast at this hour. Will maintain
tempos for MVFR conditions for now. Fog and any low stratus will
diminish after sunrise. Winds will increase from the south...with
gusts to 18kts possible. Isolated to scattered ts will be possible again
Thursday.

14



&&

Preliminary point temps/pops...
Gadsden 77 59 78 47 62 / 50 20 40 80 10
Anniston 79 59 79 49 62 / 50 20 20 80 10
Birmingham 80 61 79 47 63 / 50 20 30 80 10
Tuscaloosa 82 63 80 48 66 / 50 20 40 80 10
Calera 81 60 80 49 65 / 50 20 20 80 10
Auburn 80 57 81 52 66 / 40 10 10 50 20
Montgomery 83 58 83 54 68 / 30 10 10 50 20
Troy 83 58 84 55 68 / 30 10 10 30 20

&&

Bmx watches/warnings/advisories...
none.
&&

$$

National Weather Service Glossary of Abbreviations