Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 282358

Area Forecast Discussion
National Weather Service Birmingham AL
658 PM CDT Fri Apr 28 2017

For 00Z Aviation.


Rest of this afternoon through Saturday.

Central Alabama will be under the influence of a 500mb ridge
centered just offshore of the southeastern U.S., of which is
forecast to amplify a bit as a 500mb trough deepens over the
southwestern U.S. We`ll have a varied presence of clouds today
through Saturday, with rain-free weather dominating the period;
however, it`s plausible that we could have a stray shower/weak
pulse t`storm across central Alabama during the hours of peak
daytime heating (both today and Saturday). The chance of such
activity is `slim`/about 20%.

High temperatures today should max in the mid-upper 80s, slightly
warmer on Saturday with upper 80s becoming more common + a few
90s possible (F). With dew points in the mid-upper 60s (F),
there`ll be a bit of a muggy feel to the air mass. Additionally,
we`ve had wind gusts this afternoon in the 15-20 knot range across
the region and, with a slightly tighter upstream pressure
gradient, wind gusts of 20-25 knots are probable on Saturday
(perhaps an instance or two just over 25-knots) post erosion of
the morning inversion given warmth and anticipated mixing of low-level
southerly flow. The breeziest of winds will exist with closer
proximity to the Mississippi River, arching toward the Gulf Coast.
Given projected max gusts numbers, we`re below Wind Advisory
criteria (35-knots).

An active weather pattern is set to evolve as we head into late
Sunday afternoon, continuing into the nighttime hours -- outlined


Sunday through Thursday.

Conditions will deteriorate late in the afternoon and into the
evening as a QLCS marches across Mississippi and into Alabama.
Instability in advance of the QLCS should be confined to a
relatively narrow corridor with SBCAPE as high as 1200 J/kg across
our West and slowly diminishing with eastward extent through the
event. A strong low-level jet of 45-60kt will support a potential
for brief embedded tornadoes and damaging wind gusts. Directional
shear in the early part of the event appears rather poor with
south-southwest winds at 500mb. These vectors are expected to
become more westerly around 06z Monday, which could actually
enhance the threat across our central and eastern counties through
12z Monday as the QLCS gains momentum. For now the best chance of
severe weather will be advertised across the West, but could be
expanded eastward.

Dry conditions will return for Tuesday behind the front, but this
may be short-lived as disturbances in the northern and southern
streams combine on Wednesday. We could be looking at an extended
period of rain Wednesday afternoon through Thursday due to the
slow progression of a positively-tilted northern stream trough.



00Z TAF Discussion.

Somewhat similar conditions to last night expected overnight.
Some high clouds will be around, but expected the MVFR ceilings
developing rather quickly around 8-10z. A few spots could once
again experience IFR for a hour or so and have added some mention.
Do not think fog will be an issue anywhere tonight as the winds
will stay above 6kts at most terminals. The pressure gradient
between a high to the east and a developing low to the west will
produce gusty winds for an hour or so this evening and again on
Saturday. Winds will generally be southeast to south throughout.




Rain chances will remain low through Sunday afternoon before
increasing rapidly Sunday night into early Monday. There are no
fire weather concerns at this time.


Gadsden     68  88  69  86  61 /  10  20  10  20  90
Anniston    68  88  69  86  63 /  10  20  10  20  90
Birmingham  70  89  70  87  60 /  10  20  10  40  90
Tuscaloosa  71  90  70  86  58 /  10  20  10  60  90
Calera      70  88  69  86  60 /  10  20  10  40  90
Auburn      69  87  69  84  66 /  10  20  10  20  70
Montgomery  71  90  68  88  65 /  10  20  10  20  90
Troy        70  89  69  86  67 /  10  20  10  20  90




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