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Area forecast discussion 
National Weather Service Birmingham Alabama
331 PM CDT Monday Jul 28 2014

Discussion...

A cold front is currently moving southward across the forecast area
and looks to be near the I-85 corridor. Showers and thunderstorms
have developed south of the front. Storms have been pulsing up and
down with a few stronger storms and one severe storm so far in Pike
and Barbour counties. Dewpoints south of the front are in the middle to
upper 70s with temperatures in the low to middle 90s. This combination
has yielded SBCAPE values south of the front in the neighborhood of
3000 j/kg. The deep layer shear is weak with only 10-20 kts of 0-6
km bulk shear. Storms will continue to pulse up and down and a few
storms could briefly become severe along and south of the front
through 7 PM. Models indicate the activity will decrease rapidly
around 7 PM as the front moves through with drier air moving into
the forecast area. After the front moves through there will be a
noticeable difference associated with the drier air.

Tuesday and Wednesday will be dry with precipitable water values two Standard
deviations below normal for late July. Dewpoints will drop down into
the 50s bringing in a break from the muggy conditions over the
last few days. The coldest morning will be on Wednesday morning with
forecast temperatures already below record lows. Cold air advection
and the dry airmass will cause temperatures to drop down into the
upper 50s and low 60s on Wednesday morning.

The upper level pattern remains stagnant throughout the extended
forecast with a trough across the eastern Continental U.S. And a ridge across
the west. The lower heights aloft will keep conditions cooler than
average throughout the forecast period. The question remains when
will the moisture return. Models indicate that precipitable water values will
increase to above normal by Thursday as a shortwave trough pivots
across the southeast. This combination will lead to the next chance
of rain across central Alabama as moisture values continue to creep
up late in the week. Higher precipitation chances will continue late in
the week and into the weekend with a series of shortwaves rotating
through the broad scale trough.

05/Massachusetts

&&

Aviation...
18z taf discussion.

The front is through the northern tafs...so rain chances have been
removed. Mgm and toi still have a chance at seeing an isolated
storm this afternoon so went with thunderstorms in the vicinity with only tempo low MVFR
clouds for 2 hours. Best storm chances will be after 20z through
23z. With absolutely zero coverage at the time of taf issuance I
do not have enough confidence to include any temperature thunderstorms and rain at this
time for mgm or toi. Will amend as needed.

As for tonight...winds finally calm down after 6z and there is an
outside chance at seeing some patchy fog develop. Really depends
on how quickly the dry air can work in. Not enough confidence to
include at this time.

16



&&

Climate...

Wednesday 7/30

Station forecast temperature record low(year)

Birmingham 59 61 (1994)
Montgomery 61 66 (1889)
Tuscaloosa 60 67 (1954, 1960, 1965, 1969)
Anniston 57 61 (1903)

05/Massachusetts

&&

Preliminary point temps/pops...
Gadsden 63 83 57 84 63 / 0 0 0 0 0
Anniston 64 83 57 83 63 / 0 0 0 0 0
Birmingham 65 84 59 84 64 / 0 0 0 0 10
Tuscaloosa 65 86 60 86 65 / 0 0 0 0 10
Calera 66 85 60 85 64 / 0 0 0 0 10
Auburn 67 87 60 86 64 / 0 0 0 0 0
Montgomery 68 89 61 88 65 / 10 0 0 0 0
Troy 67 89 60 87 63 / 30 0 0 0 0

&&

Bmx watches/warnings/advisories...
none.

&&

$$

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