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fxus64 kbmx 131847 

Area forecast discussion
National Weather Service Birmingham Alabama
147 PM CDT sun Oct 13 2019

midday update and 18z aviation.


Short term...
/updated at 1256 PM CDT sun Oct 13 2019/

Similar to what we observed yesterday, more widespread rainfall
has developed than what guidance was indicating due to stronger
isentropic lift and a more potent upper level shortwave. On our
12z kbmx sounding this morning, a 50kt jet was recorded at 500mb
with over 100kts in the upper levels. That's certainly a distinct
pattern change from what we've observed earlier this month. The
rainfall will remain on the light side, since most of the rain is
falling from mid-level cloud cover due to drier air present at the
surface. Observations in Mississippi have only recorded a couple
hundredths of an inch per hour at best. Still, it will be enough
rain to cause impacts to outdoor events as we go through the rest
of the afternoon and into the early evening hours. Pops were
increased earlier to likely across much of the area, with lower
chances far to the south. As the shortwave quickly moves across
central Alabama overnight tonight, rainfall should diminish with
time, but a few leftover showers will certainly be possible across
our southern counties. Otherwise due to the widespread
cloudcover, temperatures should remain in the 50s and 60s for
most. If clouds are allowed to clear across our far northwest
counties as is currently advertised, lows could drop into the 40s
for locations such as Hamilton, Haleyville, and Double Springs.

The long-term forecast remains on track this afternoon, with
rainfall pushing southward during the day on Monday for most
locations and warmer temperatures into the 70s. Significant
rainfall amounts are still in the forecast starting Monday night
through the day on Tuesday with good agreement amongst the global
models of 1-3 inches of rain with isolated higher amounts.


Long term...
/updated at 0356 am CDT sun Oct 13 2019/

Monday through Saturday.

On the heels of a shortwave trough over the Carolinas on Monday
morning, a transient ridge will be associated with subsidence and
rain-free conditions across the northern half of the forecast area
as 700-500 mb flow gains more of a northerly component. For the
daylight ours on Monday, isolated showers cannot be ruled out in
our southern counties in closer proximity to the stalled front
near the Gulf Coast.

An upstream shortwave will begin impacting the region Monday night
into Tuesday morning as the front to our south is encouraged
northward as a warm front. Rain should overspread the area from
southwest to northeast after midnight Monday night with heavy rain
and embedded thunder possible later on Tuesday morning through
Tuesday evening. Models have introduced some uncertainty regarding
the placement higher rainfall totals with the GFS and European model (ecmwf)
showing a slight southward trend keeping the highest amounts south
of I-20. However, many of the GFS and European model (ecmwf) ensemble members more
closely resemble the NAM, with the highest amounts along the I-20
corridor. Either way, we are still expecting 1 to 3 inches of
rain for most locations through Wednesday morning.

The passage of a strong cold front will be associated with drier
conditions for Wednesday afternoon with cool mornings expected on
Thursday and Friday. The return of southerly flow on Saturday ahead
could mark the early stage of another rainy period as another large
storm system begins to take shape to our west over the weekend.



18z taf discussion.

Most terminals have finally risen above MVFR category early this
afternoon except for some temporary reductions in vis at kmgm due
to a passing heavier shower and drizzle. Meanwhile, widespread
light rain with mid-level clouds of 8 to 10k feet continue to move
into the state from the west. Widespread light rain will move over
most northern terminals from 17z to 19z and could last through
much of the early evening hours. The good news is that ceilings
shouldn't be low with this activity and should remain VFR
category. Rain should gradually taper off with time into the
evening hours, but ceilings will likely drop as well into at least
MVFR category during the early morning hours based on the latest
model guidance. At this time, IFR ceilings have not been included
due to low confidence, but trends will be monitored through the



Fire weather...

Widespread light rains are currently moving from west to east
across central Alabama. Rainfall amounts should be light,
generally less than one tenth of an inch but will help to
increase surface moisture a bit. Rain chances will shift to our
southern counties for Monday. Rain should become widespread and
potentially heavy for Tuesday morning through Tuesday evening as a
more significant disturbance moves across the region.

The Alabama forestry commission continues to have a fire alert in
effect that includes all of central Alabama. For more information
about restrictions, visit their web site at forestry.Alabama.Gov.


Preliminary point temps/pops...
Gadsden 49 77 60 68 62 / 30 10 30 90 70
Anniston 53 78 61 69 63 / 50 10 40 90 80
Birmingham 54 77 63 70 64 / 50 10 50 100 70
Tuscaloosa 53 77 64 71 65 / 50 10 70 100 70
Calera 54 76 63 70 64 / 50 10 60 100 80
Auburn 59 77 65 72 67 / 40 30 60 90 90
Montgomery 60 79 66 75 68 / 40 30 70 90 90
Troy 61 79 67 77 68 / 30 30 60 90 90


Bmx watches/warnings/advisories/...

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